Wilson v IPN Medical Centres Pty Ltd t/as Health Manly

CERTIFICATE OF DETERMINATION OF MEMBER
CITATION:	Wilson v IPN Medical Centres Pty Ltd t/as Health Manly [2021] NSWPIC 92
APPLICANT:	Sally Anne Wilson
RESPONDENT:	IPN Medical Centres Pty Ltd t/as Your Health Manly
MEMBER:	Ms Kerry Haddock
DATE OF DECISION:	22 April 2021
CATCHWORDS:	WORKERS COMPENSATION- Claim for weekly benefits and medical expenses, including the cost of proposed resection of the trapezium and suspension arthroplasty of the left and right thumbs; agreement by parties on award of weekly benefits if an award for the applicant was made; concession by respondent that proposed surgery is an appropriate treatment; application of section 4(b)(ii) of the 1987 Act; Federal Broom Co Pty Ltd v Semlitch, Cant v Catholic Schools Office and Murray v Shillingsworth applied; Held- the applicant sustained injury due to aggravation of osteoarthritis of both thumbs; award for the applicant of agreed weekly benefits and for past medical expenses and cost of surgery; liberty to the parties to apply in respect of the period of weekly benefits.
DETERMINATIONS MADE:	1. That there is an award for the applicant pursuant to section 36 of the Workers CompensationAct 1987 at the rate of $100 per week from 1 February 2018 to 3 May 2018; and pursuant to section 37 of the Workers Compensation Act 1987 at the rate of $100 per week from 4 May 2018 to 30 July 2020. 2. That there is an award for the applicant pursuant to section 60 of the Workers Compensation Act 1987 in respect of past medical expenses; and for the costs of proposed surgery, being a resection of the trapezium and suspension arthroplasty of the left and right thumbs. 3. That the parties have liberty to apply with respect to the award of weekly benefits.

STATEMENT OF REASONS

BACKGROUND

The applicant, Sally Anne Wilson (Ms Wilson), is employed by the respondent, IPN Medical Centres Pty Ltd t/as Your Health Manly (IPN), as a registered nurse.
Ms Wilson claims to have sustained injuries to her left and right thumbs as a result of the aggravation, acceleration, exacerbation or deterioration of a disease, the deemed date of injury being 1 December 2016.
The respondent’s workers’ compensation insurer, AAI Limited trading as GIO (GIO) issued the applicant with a notice pursuant to section 74 of the Workplace Injury Management andWorkers Compensation Act 1998 (the 1998 Act) on 18 April 2018.
GIO disputed liability for the applicant’s claim for left thumb suspension arthroplasty and resection of the trapezium, on the basis that the proposed surgical procedure was not a result of a work-related injury, but the applicant’s condition was constitutional and pre-existing.
GIO issued a further notice pursuant to section 74 of the 1998 Act on 22 May 2018. It disputed liability for “ongoing workers compensation benefits” for the applicant’s alleged thumb injuries.
GIO disputed that the applicant had suffered any work-related injury or aggravation. It disputed that her employment had been the main contributing factor to the onset, or aggravation, acceleration, exacerbation or deterioration of a disease, pursuant to sections 4(b)(i) and 4(b)(ii) of the Workers Compensation Act 1987 (the 1987 Act); that any incapacity for employment resulted from a work injury, pursuant to section 33 of the 1987 Act; and that any medical or related treatment was required as a result of a work injury, pursuant to section 60 of the 1987 Act. In the event that the applicant claimed that any specific incident was the sole cause of her injury, GIO disputed that she had sustained injury arising out of or in the course of her employment, pursuant to section 4 of the 1987 Act; and that employment was a substantial contributing factor to any such injury, pursuant to section 9A of the 1987 Act.
The applicant brought previous proceedings in Matter Number 4169/19. Those proceedings were discontinued.
The applicant lodged an Application to Resolve a Dispute (the Application) on 22 December 2020. She claimed weekly benefits from 1 February 2018 ongoing; past medical expenses of $2,773.86; and future medical expenses of $7,750, in respect of a resection of the trapezium and suspension arthroplasty to both thumbs.
The respondent lodged its Reply on 12 January 2021.

ISSUES FOR DETERMINATION

The parties agree that the following issues remain in dispute:

(a) whether the applicant sustained injury arising out of or in the course of her employment with the respondent;
(b) whether the applicant’s employment was the main contributing factor to the aggravation, acceleration, exacerbation or deterioration of any disease condition, and

(c) whether the proposed surgery is reasonably necessary as a result of a work-related injury, the appropriateness of the treatment itself not being in dispute.

PROCEDURE BEFORE THE COMMISSION

The matter was listed for conciliation/hearing on 1 April 2021. Mr Stephen Hickey of counsel, instructed by Mr David Dickinson, appeared for the applicant, who was present. Ms Kavita Balendra of counsel, instructed by Mr Mitchell Strachan, appeared for the respondent. Ms Jade Mallard of GIO also attended.
The Application was amended to claim weekly benefits from 1 February 2018 to 1 August 2020. The parties agreed that, should the applicant succeed in her claim, the agreed amount of the weekly benefits to be awarded pursuant to sections 36 and 37 of the 1987 Act is $100 per week.
The parties agreed that, should the applicant succeed in her claim, a general order pursuant to section 60 of the 1987 Act for past medical expenses, and a specific order for the cost of the proposed surgery, should be made.

I am satisfied that the parties to the dispute understand the nature of the application and the legal implications of any assertion made in the information supplied. I have used my best endeavours in attempting to bring the parties to the dispute to a settlement acceptable to all of them. I am satisfied that the parties have had sufficient opportunity to explore settlement and that they have been unable to reach an agreed resolution of the dispute.

EVIDENCE

Documentary evidence

The following documents were in evidence before the Commission and considered in making this determination:

(a) The Application and attachments;
(b) Reply and attachments;

(c) Application to Admit Late Documents dated 5 March 2021, filed by the applicant and admitted by consent, and

(d) Application to Admit Late Documents dated 26 March 2021, filed by the applicant and admitted by consent.

Oral evidence

The respondent sought leave to cross-examine the applicant with respect to leisure activities and hobbies, to which she has referred in her statement. The applicant did not object to this limited cross-examination, and the possibility of such an application had been foreshadowed at the telephone conference on 4 February 2021.
Leave was granted to the respondent to cross-examine the applicant.

FINDINGS AND REASONS

Evidence of the applicant, Sally Anne Wilson

The applicant’s first statement is dated 27 July 2018. She has provided evidence about her employment as a registered nurse and the hospitals and practices where she was employed.
Since 1990, the applicant has worked with a number of employers, using her hands in cannulating veins, preparing and loading infusions and then regulating the intravenous flow to the patient.
The applicant worked for the respondent at the same time as she worked for various other employers. She has worked solely for the respondent since April 2013, initially for 16 hours per week, increasing to 30 hours per week in November 2013.
In April 2016, the respondent decreased the applicant’s hours to 24 per week, but she still saw the same number of patients, that is, 10 to 12 per day.
The applicant began to experience pain in her left thumb in late 2016. She informed her manager that the pain was becoming unmanageable in September 2017. In February 2018, her hours decreased to 16 hours per week as both her thumbs were very painful.
In the main, apart from some brief periods, the applicant’s work in centres other than IPN was not as heavy and did not involve as much pressure on her wrists and thumb joints.
On a typical day, between 80% and 90% of the applicant’s work at IPN involved the use of both hands, especially her thumbs. She had been doing this type of work for over 18 years. The rest of her work involved administration, such as patient bookings by computer; writing up costing sheets and order documents; phone calls; and re-stocking stores. She writes with her right hand, but part of her regular work is using her left hand, so her right is not as dominant in her work for the respondent.
The applicant provided a detailed description of a typical day’s work. She highlighted activities that placed strain on her thumbs or involved strong thumb use. They include tearing tape to prepare kidney dishes; turning the valve to check oxygen cylinder levels; removing blood; using a roller to establish infusion rate (prolonged use of left thumb); adjusting and regulating flow of infusion; applying pressure to infusion site (using both hands and thumbs); cleaning with a pump spray; checking infusion rates; drawing fluid from bottles or ampoules (using thumbs on both hands); cutting open boxes and tearing open bags of stock (using hands and thumbs); checking and removing cannula (using hands and thumbs); tearing or peeling open syringes and equipment for Port-a-Cath access and infusion using syringes (repeated use of thumbs, with inability to wear splints, as this must be a sterile procedure); and cleaning up at the end of the day (using fingers and thumb).
The applicant stated that infusion rates must be adjusted from 8 to 10 times per patient, with longer infusions requiring at least 10 adjustments over three hours, using her thumbs. With 8 to 10 patients, that is about 80 to 100 times per day, using the thumb. It places a lot of stress on the joints of both thumbs.
Towards the end of 2016, the applicant began to notice pain and discomfort in both thumbs, first on the left. During 2017 the pain and discomfort worsened, and she had issues performing normal domestic tasks. She believed the problem was work-related.
The applicant consulted Dr Emmanuel Varipatis in October 2017 and had x-rays of both hands on 6 October 2017. She was then referred to Dr Claudia Gschwind, orthopaedic hand surgeon. She saw orthopaedic hand surgeon Dr Mark Hile in May 2018.
On 7 November 2017, the applicant submitted a claim for compensation that was initially accepted. She was referred for MRI and physiotherapy on Dr Gschwind’s recommendation and was prescribed anti-inflammatories and splints. She has been issued with two section 74 notices. She had not received any weekly payments even before the notice denying them to her.
The applicant believed her condition was worsening and she would have to cease work altogether. She wished to have the surgery recommended by her treating doctors. She suffers from osteoarthritis in the CMC (carpometacarpal) joint of both thumbs, but believed the condition was caused, aggravated or exacerbated by her employment.
The applicant’s statement includes Appendices A and B, which provide details of the work involved in preparing infusion bags and cannulation of patients.
On 11 September 2019, the applicant stated that she continued to work for IPN two days per week, with increased difficulty due to pain.
The applicant had seen Dr Frank Machart and told him about the problems she was having, the pain in both thumbs and the history of the onset of pain initially in her left thumb in 2016 and later in her right.
The applicant was being treated conservatively with physiotherapy from Dr Anne Wajon, osteopathy and some naturopathic treatments. This helped her to manage her condition but surgery, initially in the worst affected thumb joint, appeared to be necessary.
The applicant was unable to participate in some of her pre-injury leisure activities including ceramics, basket weaving, knitting and tennis. She still did some light gardening but was limited in what she could do.
The applicant could not lift anything over two kgs, which significantly restricted her performing any nursing duties. She had tried to find other nursing work. She worked for two days at Delmar Private Hospital but realised she could not do the work because of her injuries. Her last day of work there was 22 February 2018.
The applicant stated that all nursing work involves lifting, fine motor skills and changing dressings and drains. Even giving pills and administering drugs involves use of the hands, with the thumbs as part of the grasping action.
The applicant still saw the same number of patients, but was slower, as she had to take off both splints to wash her hands before and after attending to them. The most difficulty she had was attending to procedures for Port-a-Cath access, to enable infusion of fluids to the superior vena cava on the right side of the heart. As access must be aseptic, she cannot wear her splints, which greatly aggravates her condition.
On 17 February 2021, the applicant stated that she had managed to continue working 16 hours per week (two days per week) at Your Health Northern Beaches, though with increased difficulty due to pain.
Since her last statement, the applicant’s right thumb CMC joint had gradually become more painful. She had an MRI of her right thumb on 17 July 2020.
Ms Wilson saw Dr Gschwind on 9 September 2020. She reviewed the latest MRI and suggested the applicant wear a longer splint, which extended past the wrist, to fully rest her hand. When she became aware that this meant the applicant could not use her hands for work, she agreed that the longer splint would best be used after work hours, to rest the joint.
The applicant was seen by Dr Gschwind’s physiotherapist, who designed the splint, but it was too uncomfortable. She adjusted it, but Ms Wilson was still unable to wear it.
The applicant returned to Dr Wajon, who designed an extended splint that she could wear after work to rest her hands fully.
The applicant stated that she was unable to grasp anything pain free, without the protection of her bilateral splints, so Dr Gschwind’s recommendation for surgery seemed to be the only option, as steroid injections had failed to make any difference when tested on her left CMC thumb joint.
Ms Wilson again saw Dr Machart at the request of her solicitor on 6 November 2020. She told him about the problems she was having and the pain she was experiencing in both thumbs.
The applicant’s original position at the IV clinic Your Health Manly was transferred to Brookvale and was then known as Your Health Northern Beaches. This clinic closed on 17 December 2020. Ms Wilson began to work for two days (16 hours) per week at the IV clinic Nature Care Wholistic & Medical Centre, Crows Nest, on 21 December 2020.

Applicant’s oral evidence

The applicant was cross-examined about what she had described as her pre-injury leisure activities.
The applicant gave evidence that she had done ceramics about 20 years ago. She has a wheel under the house that she hasn’t used for about 20 years. She did a course in basket weaving at Moss Vale about 15 years ago and made three baskets. She had not done anything probably for the last 10 or 12 years. It needs a lot of strength in the thumb and fingers.
The applicant knitted half a scarf last year, “just quietly over the year”. She had tried it for a little bit and it started to hurt, so she could not continue. This was with her splints on. She knitted in the winter last year, maybe once or twice a week, just for maybe half an hour or an hour.
Before 2016, the applicant didn’t knit very much at all. She gave it a try to see whether she could, because she wasn’t able to do the baskets or the ceramics.
The applicant was asked whether she partook in knitting at all pre-injury. She responded that she did, many years ago, but she did try it last year. “They” asked her what activities she wasn’t able to do, so she named the activities she wasn’t able to do any more. It was put to her that ceramics and basket weaving were not activities she was doing anyway. She answered, “not for a long while, no”.
The applicant gave evidence that she last played tennis two or three years ago. She played maybe once per fortnight, social tennis for maybe half an hour or an hour. She stopped because she had no strength in her hands with the splints on. If somebody served a bit hard “it’s pretty hopeless. You can’t return the ball.”
The applicant agreed that you need to grip the racket hard, which was not easy for her to do. She used to be able to play with just one hand holding the racket but ended up having to try it with two. Then it was just too uncomfortable, so she didn’t try to do it any more.
The applicant’s evidence was that she last played tennis probably in 2018, because it was starting to get uncomfortable in 2016, so “it would have been… the end of 2017, beginning of 2018”.

Medical evidence
Dr Claudia R Gschwind – Hand Surgeon

Dr Gschwind reported to Dr Varipatis on 1 December 2017. She recorded that the applicant had had pain at the base of both thumbs since the end of 2016.
On examination, the applicant clearly had pain in the STT (scapho-trapezium/trapezoid) and CMC joints in both thumbs. Her x-rays showed osteoarthritis, even though it was very mild. Radiological changes are not early signs of osteoarthritis.
Dr Gschwind was to start with a CMC protection splint on the left side and see how the applicant progressed over the next three weeks. If her symptoms did not improve, she would proceed to an intra-articular steroid injection. Next time, she would decide if she could start splinting the right side, which was less symptomatic.
On 27 December 2017, Dr Gschwind reported that the applicant was quite comfortable in the splint and the pain in her left thumb was controlled. As soon as she took off the splint, she again had pain.
Dr Gschwind had injected the applicant’s CMC joint. The STT joint was not as irritable as it used to be. In four weeks’ time they would discuss splinting the right side.
Dr Gschwind again reported on 29 January 2018. Despite wearing a splint and having a steroid injection into the CMC joint, the applicant was still exquisitely tender in the same joint and in the STT joint.
Dr Gschwind was not satisfied with the applicant’s progress. She thought Ms Wilson needed an MRI of her left wrist to see if there were signs of a more systemic inflammatory change. She had also been given a CMC protection splint for her right hand.
On 26 February 2018, Dr Gschwind reported that the applicant was not in any pain when wearing the splint, but she could “clearly not wear the splint for the rest of her life”. The applicant was still exquisitely tender in the CMC joint and to a lesser degree the STT joint on the left. The MRI showed severe CMC joint and moderate STT joint arthritis.
Dr Gschwind opined that the applicant’s only way forward would be a resection of the trapezium and suspension arthroplasty. This would “put her out of her usual work routine for about three months”. She should be fit for desk type activities after about six weeks.
On 25 March 2021, Dr Gschwind reported to the applicant’s solicitors. She referred to her review of the applicant in September 2020, with her MRI from July 2020 and x-rays taken in September 2020.
Dr Gschwind opined that, given the long duration of pain in the bases of both the applicant’s thumbs and the lack of conservative management to eliminate it, surgery to both thumb bases is now reasonably necessary.
There are different surgical solutions, but Dr Gschwind preferred a resection of the trapezium and suspension arthroplasty with an FCR (flexor carpi radialis) tendon as the most reliable option. She estimated her fee as $2,765. In addition, there would be an anaesthetist fee and the excess for private insurance payable to North Shore Private Hospital

Professor William J Cumming – Orthopaedic Surgeon

Professor Cumming was qualified by the respondent and reported first on 13 April 2018.
Prof Cumming recorded that the applicant is right-hand dominant, and the area of injury was to her left upper extremity, although her right upper extremity was also involved to a lesser degree.
The applicant’s condition related to pain in the thumb base region, which commenced slowly, without significant incident, over several weeks. It commenced in her left hand and subsequently her right hand became painful because she felt she was favouring her left side.
Prof Cumming recorded that there were no mechanical symptoms, although the applicant had a sharp electric pain from time to time. The pain was worse with thumb use, particularly at work, where she was involved with a particular task. She also had night pain and pain with activities outside the workplace.
As the applicant’s condition did not improve, she attended a doctor at work, who thought it may have been muscular or an inflammation and arranged an x-ray.
The applicant was referred to Dr Gschwind, who arranged splintage for three weeks. This assisted to a degree. A cortisone injection was given into the dorsal aspect of the left thumb base, which did not assist. It was suggested that the injection be given from the volar aspect, but Ms Wilson declined this.
The applicant had had an MRI, which she stated showed there was no cartilage left in the CMC articulation. She had continued with splintage and Dr Gschwind had suggested she undergo excision of the trapezium and the use of tendon to provide a suspension arthroplasty. The applicant wished to proceed with that treatment.
Prof Cumming recorded a history that the applicant was working three days per week, in an organisation related to allergy care. There was a detox clinic where patients had an intravenous drip of Vitamin C and other measures. There were 10 to 12 patients each day and the applicant adjusted the drips approximately 100 times per day. She demonstrated this for the doctor.
Since January (2018) the applicant had been working two days per week, but there was [sic: no] improvement and her condition was progressive. She was wearing hard thumb base splints, encircling her wrists and thumb to the IP (interphalangeal) articulation.
Prof Cumming recorded that the applicant had had a right shoulder repair. She was not diabetic and did not suffer from anxiety or depression. Her father had osteoarthritis in the joints of his hands, but he was a farmer, and she believes the problem was due to his hands being caught in the farm gates.
The applicant had difficulty with pulling up her pants or putting on her bra, as she had to pinch and pull. She could not garden and her partner needed to help with opening jars. Such tasks as using a screwdriver or a key in a lock were very painful. She drove a manual car, which she preferred, with the gearstick on the left. She found gripping the steering wheel painful. She had needed to cease tennis and yoga.
Prof Cumming noted that the applicant had provided him with significant information about the two sets of drips she used at work.
Prof Cumming performed an examination, finding some limitation of cervical movement. He considered Ms Wilson had moderate to significant degenerative changes in her cervical spine. She had some limitation of movement in her right shoulder, but there was a reasonable range, and a full range on the left.
The applicant had a full range of thumb movement on the right, but on the left, the thumb base movement appeared diminished by 10 degrees to 15 degrees in abduction and opposition. On circumduction test of her thumb bases, she had a sharp pain on the right, so the test on the left was carried out extremely carefully. On the left, there was limitation of movement of the CMC articulation at the thumb base. The clinical findings were of significant osteoarthritis of the bilateral CMC articulation.
Prof Cumming had access to an x-ray report dated 6 October 2017 and MRI report dated 14 February 2018. He opined that the MRI study was conclusive of significant osteoarthritis at the thumb bases.
The applicant had brought two infusion sets. Prof Cumming noted that the drip rate is controlled by rolling a wheel inside a channel, gradually occluding the fine tubing and allowing for drip rate control.
Prof Cumming reported that it was quite difficult for the first wheel to be moved down to a full turn off position without significant thumb finger grip rolling with the thumb. The applicant demonstrated how she now performed this by holding the instrument in the palm of her hand, with her fingers, not using the thumb, and rolling it with the contralateral index.
Prof Cumming noted pre-existing disease of the bilateral basal joints. The applicant’s employment was not a substantial contributing factor to the presence of this condition, and there was no specific injury. He opined that the nature of her employment and the specific tasks were an aggravating factor on a symptomatic basis, as were activities outside the workplace, such as driving, pinching a key, using a screwdriver, opening jars etc.
In Prof Cumming’s opinion, the condition would have happened at about the same time in Ms Wilson’s life whether she had or had not been at work. Her father had the condition, which is constitutional and familial. It is the most common form of osteoarthritis in the upper extremity and more common in females. The presence of the other degenerative conditions noted on MRI, and the presence of DIP (distal interphalangeal) joint arthritis on x-ray confirmed the constitutional nature of the problem.
Prof Cumming opined that the applicant had not suffered a work-related injury. The proposed surgery was reasonable and medically necessary, but not for any work-related condition. Further treatment may be required but it was not the responsibility of the employer or insurer. He emphasised that the applicant’s condition was purely constitutional and was aggravated by workplace activities and those outside the workplace that were equally distressing. Pain with activity is a protective mechanism for patients with osteoarthritis.
Prof Cumming provided a supplementary report dated 10 May 2018. He had been asked to clarify whether the applicant’s employment had, or had not been, the main contributing factor to the alleged aggravation of a disease.
Prof Cumming responded that it is necessary to differentiate between the painful symptoms that occur in any inflammatory condition, including osteoarthritis, and the question of aggravation, acceleration, exacerbation or deterioration of a disease subsequent to activities that have produced symptoms.
In Prof Cumming’s opinion, the applicant’s condition was constitutional, and the pain was a warning that she had osteoarthritis, and activity would be painful whether it occurred inside or outside the workplace. Ms Wilson’s occupation, including the specific activities that she noted aggravated her condition, are not the cause of the condition; and nor did they alter the pathology of it when she carried them out.
Prof Cumming noted that the applicant’s initial and major problem was in her left, non-dominant, hand. He opined that “if it is argued that this is a disease injury situation”, her occupation was not the main contributing factor to the aggravation. Her symptoms occur also with activities outside the workplace.
The particular activity (performed by the applicant) required a pinch between the thumb and fingers; and Prof Cumming spent some time with her assessing it. There was a range of activities outside of employment that also contributed. They are painful, but it was not determined that each individual activity inside or outside the workplace altered the pathology in the joint – this was constitutional and pre-existing. The symptoms such as pain were a warning sign that the pathological process was significant, but it was not appropriate to attribute even the activity at work to producing a change in the pathology of the articulation.
Prof Cumming opined that the applicant’s activities outside the workplace were not the main contributing factor to any aggravation of the disease. It was not necessary to postulate that her condition must be related to something either inside or outside the workplace. It is constitutional and its causation was irrelevant to where she was or what she was doing, as was its natural progression and relentless progress in many patients.
Prof Cumming further opined that it is necessary not to make the presumption that because an activity produces pain, it is causing alteration in an already existing degenerative joint. By that, he meant the disease process that was producing the actual pathology within the joint.
Prof Cumming opined that the proposed surgery was required as a result of the constitutional condition of osteoarthritis. He commented on the applicant’s contralateral hand, where she had considered she was favouring one hand, causing overload of the other. There is extensive literature that does not support this phenomenon.
The nature of the proposed surgery was to remove the trapezium bone. If the arthritic process was as described on MRI, many surgeons introduce a tendon that is a portion of the FCR tendon as a suspension arthroplasty. This was conjecture on his part, but was in fact correct, as that was the procedure favoured by Dr Gschwind.
The proposed surgery was designed to treat the loss of articular cartilage, that is, the osteoarthritis at the CMC articulation. The pathology was caused by a constitutional condition, and not by any work-related aggravation. It would have occurred had the applicant been at work or not, as would the symptoms caused by that pathology.

Prof Cumming provided a further supplementary report dated 28 October 2019. He had been provided with a video of a nursing sister attending to a drip system.
Prof Cumming reported that Ms Wilson had described the tasks in detail, and as he had been involved in general and hospital practice for 65 years, he was very and completely aware of the duties. He had carried them out himself on many occasions. Having viewed the video three times, his opinion had not altered.
Prof Cumming was asked whether or not the applicant’s actions caused her to develop pathology. He responded that “you are quite right” in stating that that is the question, and “in relation to that by stating whether these actions were the main contributing factor to increasing the pathology” that was present at the thumb base. His opinion in the negative remained unchanged.
Prof Cumming maintained his view that Ms Wilson’s employment was not a substantial contributing factor to the presence of her condition; or the main contributing factor to any negative alteration in pathology in her thumb base, that is, an increase in pathology.

Dr Ann Wajon – Physiotherapist

Dr Wajon wrote to Dr Hile on 17 May 2018. She reported that the applicant had presented that day with a diagnosis of bilateral CMC OA (CMC osteoarthritis). She was right hand dominant.
The applicant had reported a history of pain in both thumbs, aggravated by cannulating and rolling the infusion pump, which she performed repeatedly throughout the day. She had had a left thumb CSI (corticosteroid injection), without relief, was reluctant to have another, and was certainly keen to avoid surgery.
Dr Wajon noted that the applicant was initially accepted as a workers’ compensation claim, but independent medical examination with Prof Cumming had resulted in that being cancelled. The applicant was “keen” to seek Dr Hile’s opinion about whether this could be disputed. The increased pain in her thumbs had resulted in her having to drop from working four days per week to two.
The applicant had local tenderness at the base of both thumbs. She had a positive grind test and tenderness on palpation of the joint margins. She had been provided with volar thumb and wrist splints, which she wore when she was able, but was unable to wear them at work.
Dr Wajon had provided advice and education about avoiding aggravating activities. She did “not doubt that her work tasks aggravate her symptoms”; and had attempted to provide splints that Ms Wilson would be able to wear at work. She had also encouraged the applicant to use heat, massage, nerve glides and address ergonomic concerns.
Dr Wajon was to review the applicant in a fortnight, but there are no further reports from her.

Dr Mark Hile – Orthopaedic Surgeon

Dr Hile reported on 30 May 2018. He recorded a history that the applicant had been having problems with both thumbs since 2016. Through 2017, she started to be assessed and have treatment.
The applicant’s treatment had consisted largely of splints and activity modification. She had had an injection on the left side but felt it did not provide any benefit. She continued to be troubled by pain and felt she had to wear splints reasonably continuously. Surgery had been recommended for her left side.
Dr Hile recorded that the applicant had pain throughout the day when she did grasping or holding tasks. She had pain at night unless she was wearing her splints. She could not recall any clunking symptoms or significant swelling. She did not have any neurological symptoms.
Dr Hile examined the applicant and recorded tenderness around both CMC joints. There was pain and crepitus on grinding both. There was only mild tenderness more proximally around the STT joint. On the right, there was tenderness around the pisotriquetral joint, with crepitus on grinding.
Dr Hile reported that x-rays and MRI confirmed the applicant had isolated CMC joint arthritis. The MRI of her right side also showed the pisotriquetral arthritis. There were other incidental findings that were not of great relevance.
Dr Hile opined that the applicant had arthritis of her thumbs. He had gone over some simple measures to manage that. Whether her arthritis was caused by her employment “is always a very difficult question”. The applicant had seen an insurance company independent medical examiner. One question he raised was why she had arthritis in her non-dominant hand. Dr Hile thought this showed a lack of appreciation of the amount of use people make of both hands. Not uncommonly, it is the non-dominant hand that presents with more symptomatic or worse arthritis.
Dr Hile opined that if the applicant wished to pursue the issue of causation, that was something she needed to do herself, probably through a solicitor. If she wished to have treatment based on her pain reaching an intolerable level, surgery would be her best option; and a trapeziectomy and suspension would be the appropriate treatment.

Dr Frank Machart – Orthopaedic Surgeon

Dr Machart was qualified by the applicant and reported first on 12 November 2018.
Dr Machart recorded a history of the onset of pain in the applicant’s left thumb in 2016, in the region of the CMC joint, and gradually increasing in severity. She experienced pain when operating IV lines, using a small wheel on the thumb. She showed Dr Machart the 50 ml syringes used to draw up the drugs. About six months later she developed pain in the right thumb.
The applicant reported the condition in 2017 and her work was reduced from three days to two days per week. She was referred to Dr Gschwind and treated with physiotherapy and splintage. She had a cortisone injection that did not help. There was talk of surgery, which Dr Machart assumed to be arthrodesis; and the applicant had seen Dr Hile for a second opinion.
Dr Machart recorded the applicant’s symptoms as pain in both thumbs at the base, equal in severity and of variable intensity. It was aggravated by physical activities, usual work duties, putting on clothes, and making a cup of tea.
On examination, Dr Machart found tender swelling at the base of each thumb. Movement was painful; and reduced at the CMC joint by a quarter, slightly more reduced on the left. He noted the x-ray and MRI reports that confirmed osteoarthritis.
Dr Machart had reviewed the video, “presumably example of what she is doing”, demonstrating nursing duties as per her description, operating IV lines, drawing up drugs and controlling flow with thumb control. The applicant said this was a stressful physical situation, she used both thumbs, and used her right hand for writing.
Dr Machart diagnosed osteoarthritis at the base of each thumb’s CMC joint, which was a symptomatic lesion. The STT joint arthritis was mild and not symptomatic. The condition was predominantly constitutional. Having reviewed carefully the nature of Ms Wilson’s duties, “there is a case to be made for aggravation without structural injury, through physical activities of her day-to-day work”.
Dr Machart opined that the applicant’s condition was not caused by the injury. The injury was aggravation of constitutional osteoarthritis. The arthritic symptoms were exacerbated and aggravated by the nature and conditions of employment, to the extent where symptoms of osteoarthritis were evident earlier than they would have been otherwise, and “now severe”. Work was a substantial contributing factor to the aggravation of osteoarthritis. The aggravation was ongoing.
The applicant’s treatment options included arthrodesis of the CMC joint. The arthritic condition would continue to be symptomatic and increase in severity, particularly if she continued the same work.
Dr Machart responded to some questions from the applicant’s solicitor in a report dated 6 March 2020. He opined that the applicant’s employment was the main contributing factor to the acceleration of osteoarthritis. Aggravation was evident. He saw no other factors contributing to aggravation.
Given the longevity and duties of the applicant’s employment, Dr Machart opined that employment was the main contributing factor to the development of osteoarthritis. He conceded that it could be argued that osteoarthritis is a constitutional condition. Given the longevity of the applicant’s employment, it could equally be argued that employment was the main contributing factor. On the balance of probability, he would argue the latter.
Dr Machart again saw the applicant on 6 November 2020 and reported on 11 November 2020. He reviewed the applicant’s history and treatment.
Dr Machart reported that he had diagnosed osteoarthritis at the base of each thumb, in the CMC joint, which was symptomatic. STT arthritis was mild and not symptomatic. Osteoarthritis in the CMC joint was deemed to be constitutional; and there was aggravation from employment.
The applicant’s symptoms had remained much the same. The right thumb was worse than the left. She continued to work two days per week, with a 2 kg lifting restriction. Her current treatment was thumb splints.
The applicant had new x-rays and MRIs, dated 9 September 2020. They showed predominantly CMC joint arthritis at the base of the thumb, almost down to the bone, and subluxation of the joint, in keeping with the diagnostic features that were clinically evident.
Dr Machart recorded symptoms of pain at the base of each thumb, right worse than left, of variable intensity. The applicant was unable to participate in basket weaving, weeding and ceramics. Knitting was difficult.
Dr Machart’s diagnosis was of osteoarthritis at the base of each thumb at the CMC joint, the right symptomatically worse than the left, with aggravation through the work practices described – IV administering nurse over several years.
Dr Machart opined that causation was a combination of constitutional osteoarthritis. Aggravation through work practices caused the condition to be symptomatic. He had diagnosed aggravation through the nature and conditions of employment. Work was the main and only contributing factor to the aggravation. He did not see any other aggravating factors, and the aggravation was ongoing. The applicant’s symptoms had not resolved.
The applicant’s treatment needs included splintage, anti-inflammatories and modification of activities. A case could be made for arthrodesis of the CMC joint at the base of each thumb, which Dr Machart recommended.

SUBMISSIONS

Counsels’ submissions have been recorded and a transcript is available. I will therefore refer only briefly to the submissions.

Applicant

The applicant submitted that she claims injury on the basis of the nature and conditions of her employment. She referred to her evidence about her duties and her detailed description. She considered her work for the respondent as the work that gave her most bother with her thumb joints.
The applicant submitted that her work was repetitive, busy and detailed, requiring significant use of her hands, because of the number of patients she had to attend to. She referred to the Appendices to her first statement. She had given evidence about the activities involved in all nursing work.
The applicant referred to the various investigations and treatment she has undergone and to Dr Gschwind’s evidence about the proposed surgery.
The applicant submitted that Dr Wajon had reported that she had no doubt her work tasks aggravated her symptoms.
The applicant referred to Dr Machart’s evidence. She submitted that, consistently with Prof Cumming, he said the condition was predominantly constitutional. However, having reviewed carefully the nature of her duties – which she submitted was important – he opined that there was a case to be made of aggravation without structural injury, through physical activities of her day-to-day work.
The applicant submitted that it was significant that Dr Machart reported that her symptoms were evident earlier than they would have been, because Prof Cumming reported that what she was exhibiting was what she would have exhibited otherwise. Dr Machart was referring to the aggravation, or as he put it, the exacerbation and the aggravation by the nature of the work.
The applicant submitted that there was a question as to whether the symptoms or aggravation were ongoing, and that on her evidence I would accept that was so. This is particularly important in the context of a section 4(b)(ii) (of the 1987 Act) injury case. She need only prove employment was the main contributing factor to the aggravation, exacerbation or acceleration, not to the underlying condition.
The applicant relied on the High Court decision of Federal Broom Co Pty Ltd v Semlitch [1964] HCA 34; (1964) 110 CLR 626 (Federal Broom) and the decision of his Honour Judge Burke of the Compensation Court in Cant v Catholic Schools Office [2000] NSWCC 37; (2000) 20 NSWCCR 88 (Cant), in which his Honour summarised what the applicant was submitting in relation to Federal Broom. His Honour referred to the need only to prove the aggravation of the underlying condition, not the disease itself. The thrust of the comment is there is aggravation of the disease if the symptoms and restrictions emanating from it have increased and become more serious to the injured worker.
The applicant referred also to the decision of Einstein J in Murray v Shillingsworth [2006] NSWCA 367 (Shillingsworth). She submitted that it deals with the need to look only at the aggravation of the underlying condition and not the need to show that the condition itself has increased pathologically or by way of some physical sign.
The applicant then referred to Dr Machart’s evidence. He is at odds with Prof Cumming in that the aggravation is continuing. It’s not just a short-term aggravation every time the applicant does something physical. She has an increased aggravation, but Dr Machart’s view is that it is earlier in terms of its ongoing nature than it would have been otherwise and is now severe. That fortifies her position with regard to what was said in Cant, Federal Broom and Shillingsworth.
Dr Machart has said that he saw no other factors contributing to the aggravation. The applicant said in her evidence that she did basket weaving, played tennis and knitted. She perceived that the respondent would submit that this must be taken into account as something that perhaps the doctors haven’t had drawn to their attention in detail. Prof Cumming has said what the applicant exhibits is what she would exhibit without work. She submitted that this may be seen as a little unrealistic and one-eyed, when the detail of her work history over the years is considered.

146.The applicant referred to Dr Machart’s apparent change of course from a section 4(b)(ii) injury to a section 4(b)(i) injury in his report dated 6 March 2020. She submitted that his final opinion seems to be that what she suffers from is a section 4(b)(ii) injury – “he’s come back to that”. But he has done that in the light of supporting also a section 4(b)(i) injury in that second report, because he obviously thought the applicant’s work history was very significant in terms of the development, perhaps, of her osteoarthritic condition. We have to be mindful that he doesn’t deny that it’s a somewhat constitutional problem.

The applicant referred to Dr Machart’s last report, in which he said aggravation through work practices caused her condition to be symptomatic – section 4(b)(ii). He thought work was the main contributing factor to the full extent. He didn’t see any other aggravating factors.
The applicant submitted that Prof Cumming denies the crucial consideration of cases like Cant, Shillingsworth and Federal Broom. She asked if he was hard and fast to his opinion because he was not looking at the matter in detail? She submitted that he did look at it but didn’t come out with the proper consideration. All you need to have is work being the main contributing factor to the aggravation of the underlying condition only. It is only to the extent of that aggravation that you apply the main contributing factor to deal with the causality problem raised by section 4. The applicant submitted that Prof Cumming looked at it but did not deal with it in the way it needs to be properly considered.
The applicant made submissions on the reasonable necessity of the proposed surgery, which it is unnecessary to consider, given the respondent’s concession in this regard.
The applicant submitted that I would make an award in her favour on the finding of a section 4(b)(ii) injury to both thumbs, as pleaded, principally the CMC joint, persuaded by the evidence of Drs Hile, Gschwind and Machart. All three recommend surgery and she wishes to have it.
In reply to the respondent, the applicant submitted that, contrary to its submission that one must show a structural or pathological change as result of injury, it being aggravation, exacerbation or acceleration, the authorities differ.
The applicant again referred to the decisions in Shillingsworth and Cant. She submitted that all one needs to show, irrespective of whether the pathology has been accelerated, is that there is relevant aggravation etc or exacerbation of the disease if the symptoms and restrictions emanating from it have been increased or become more serious to the injured worker.
The applicant accepted that once symptoms stop, there may no longer be an aggravation, but Dr Machart said there had been an exacerbation and aggravation and the symptoms were ongoing.

Respondent

The respondent submitted that the issue of whether or not the proposed surgery is reasonable and medically necessary is a “non-issue”. Prof Cumming says the proposed surgery is reasonable and medically necessary but not for any work-related condition. So, the real question is whether or not it is for a work-related condition.
The respondent referred to Prof Cumming’s evidence that the applicant’s employment is an aggravating factor, but similar aggravating factors can be found in driving, pinching a key and using a screwdriver. He expressed the opinion that the condition would have happened around the same time if the applicant had or had not been at work.
The respondent submitted that Prof Cumming’s reason for saying the applicant’s condition is not work-related can be found in his opinion that “this is a constitutional condition aggravated by workplace and activities outside the workplace which are equally distressing and pain with activity is a protective mechanism in such patients with osteoarthritis”.
The respondent submitted that the distinction drawn by Prof Cumming is between pain or symptomatic pain that is caused by various activities, and an aggravation of the actual underlying constitutional condition. He said the specific activities that the applicant has noted aggravate her condition are not the cause of the condition, and nor do they alter the pathology of it when she carries them out. He explained the difference between an activity that produces pain and one that causes an alteration in a degenerative joint.
The respondent submitted that Prof Cumming’s evidence is that the natural history of the condition is that it produces symptoms with activities, and becomes progressively symptomatic, even in the absence of such activities. That is precisely the description of what has been occurring with the applicant’s injury. Her evidence is that it has gotten to a stage where she is now unable to do a whole range of activities because she is almost always symptomatic.
The respondent referred to Dr Hile’s report, in which he said that the applicant got pain through the day when she did grasping or holding tasks. These are precisely the sort of tasks Prof Cumming said would create pain symptoms. A splint managed the night symptoms. The respondent submitted that this suggests it is a range of activities that caused the applicant’s symptomatic pain, rather than specific work activities.
The respondent submitted that it is clear from cases such as Federal Broom and Shillingsworth that what is required is some increase in actual progression of the disease. Dr Machart said there hasn’t been a structural injury. There hasn’t been that required increase in or acceleration in the pathology of the disease. The only thing Dr Machart has suggested is that there is an aggravation, and he hasn’t drawn a distinction, as Prof Cumming has, between a pain aggravation and an actual pathological aggravation, as a result of the applicant’s work activities.
The respondent submitted that Dr Machart says employment is the main contributing factor to acceleration of osteoarthritis without actually suggesting there is any acceleration of the pathological condition; and suggests longevity of employment is a basis for suggesting there is an aggravation of a constitutional condition. It submitted there was some confusion in the doctor’s mind, which may be the result of the question he was asked, but the answer was too confusing to be relied on.
The respondent submitted that the applicant’s evidence was that playing tennis required strength in her grip. She had no longer been able to do that since 2018. Dr Machart has not commented at all on those sorts of activities where she was continuously holding her hand in a particular position, requiring grip strength.
The respondent finally submitted that what I need to be satisfied about is whether or not the alleged aggravation has resulted in a change in pathology or acceleration of the pathology of the disease. Given that both Dr Machart and Prof Cumming stated that there hasn’t been a structural change as a result of the work, the respondent submitted that I cannot be satisfied that work has caused a relevant aggravation or acceleration of the underlying osteoarthritic condition.

SUMMARY

Section 4 of the 1987 Act provides:
“‘injury’ --
(a) means personal injury arising out of or in the course of employment,
(b) includes a
‘disease injury’, which means--
(i) a disease that is contracted by a worker in the course of employment but only if the employment was the main contributing factor to contracting the disease, and
(ii) the aggravation, acceleration, exacerbation or deterioration in the course of employment of any disease, but only if the employment was the main contributing factor to the aggravation, acceleration, exacerbation or deterioration of the disease, and
…”
For convenience, I will use the term “aggravation” where the phrase “aggravation, acceleration, exacerbation or deterioration” appears in section 4(b)(ii) of the 1987 Act.
In Austin v Director General of Education (1994) 10 NSWCCR 373, Clarke JA, applying Federal Broom, said a judge, faced with the potential application of the “disease” provisions, should ask the following questions:
“(a)    Was the applicant suffering from a disease?
(b)     If so, was there an aggravation, acceleration, exacerbation or deterioration of it?
(c)     If so, was her (his) employment a contributing factor?
(d)     If so, did a total or partial incapacity for work result from such aggravation, acceleration, exacerbation or deterioration?”
There is no dispute in this matter that the applicant is suffering from the disease of osteoarthritis.
Sections 4(b)(i) and (ii) of the 1987 Act now provide that a worker must establish that employment was the main contributing factor to the contraction of the disease, or its aggravation.
The respondent has conceded that, if the dispute is determined in the applicant’s favour, she had a partial incapacity for work during the period from 1 February 2018 to 1 August 2020; and that she is entitled to weekly benefits of $100 per week during that period, pursuant to sections 36 and 37 of the 1987 Act. I note that the period of 130 weeks expired on 30 July 2020.
The applicant relies on section 4(b)(ii) of the 1987 Act, asserting that she has sustained aggravation of the disease of osteoarthritis, to which her employment with the respondent was the main contributing factor.
The respondent disputes that the applicant’s employment has aggravated the disease, and that her employment with it was the main contributing factor to such aggravation.

The medical evidence in this matter essentially comes down to a contest between Dr Machart and Prof Cumming, as there is no evidence from the treating specialist, Dr Gschwind, as to causation. Dr Hile’s evidence in this regard is of limited assistance. I have also had the benefit of evidence from Dr Wajon.
The applicant’s evidence, which is uncontested, and which I accept, is that her work activities involve repetitive use of her hands and thumbs, and what she has described as “strong” thumb use. She has provided a very detailed description of a typical day’s activities and two appendices to her first statement.
Both Dr Machart and Prof Cumming were aware of the activities required of the applicant in her employment with the respondent, and in fact each viewed a video recording of similar activities. Prof Cumming pointed out that, having been in practice for 65 years, he was well aware of what was involved in adjusting a drip system and had done it himself many times.
It is first necessary to consider whether the applicant has sustained injury due to the aggravation of a disease.
In Federal Broom, Kitto J agreed with what Moffitt J had said in the Court of Appeal:
“There is an exacerbation of a disease where the experience of the disease by the patient is increased or intensified by an increase or intensifying of symptoms. The word is directed to the individual and the effect of the disease upon him rather than being concerned with the underlying mechanism”. (Emphasis added).
Windeyer J said in Federal Broom:
“The question that each poses is, it seems to me, whether the disease has been made worse in the sense of more grave, more grievous or more serious in its effects upon the patient.”
Burke CCJ applied Federal Broom in Cant, where he said:
“The thrust of these comments is that irrespective of whether the pathology has been accelerated there is a relevant aggravation or exacerbation of the disease if the symptoms and restrictions emanating from it have increased and become more serious to the injured worker.” (Emphasis added).
The proper test is whether the aggravation impacted the individual concerned. It is not necessary for the particular disease to be made worse: Cabramatta Motor Body Repairers (NSW) Pty Ltd v Raymond [2006] NSWWCCPD 132; (2006) 6 DDCR 79 (Raymond) applying Federal Broom and Cant.
Moore ADP referred to Raymond in Rural Press Limited v Hancock [2009] NSWWCCPD 160 [at 67], where she said:
“The proper test then is whether the aggravation to which the employment was a contributing factor had some tangible effect on the worker. It is not necessary for the particular disease to be made worse…” (emphasis in original); and [at 74]:
“It is clear that symptoms or pain brought on by a work activity may constitute a relevant aggravation even though no pathological change in the underlying condition has occurred (Commonwealth of Australia v Beattie [1981] FCA 88; (1981) 35 ALR 369). What is necessary is to decide whether the manifestation of symptoms is sufficient to establish ‘injury’, or, in other words, whether the symptoms were made worse by the work duties described (Mellor v Australian Postal Corporation [2009] FCA 504.” (Emphasis added).
I am satisfied that the applicant has sustained an aggravation of the disease of osteoarthritis of her left and right thumbs in the course of her employment with the respondent.
As the applicant has submitted, her work for the respondent was repetitive, busy and detailed, requiring significant use of her hands. Her evidence is that her work for IPN was heavier than elsewhere and involved more pressure on her wrists and thumb joints. She estimated that between 80% and 90% of her work at IPN involved the use of both hands, especially her thumbs.
It is clear that Dr Hile, Dr Machart and Prof Cumming agree that the applicant’s osteoarthritis is a constitutional condition. Dr Machart and Prof Cumming differ on the question of whether the condition has been aggravated by her work for the respondent. Dr Hile believes causation “is always a very difficult question”, but appears to have been considering the causation of a section 4(b)(i) injury, rather than a section 4(b)(ii) injury,
The case law is clear that the applicant need not establish that the pathology of her condition has been aggravated by her employment. As Burke CCJ said in Cant, there is a relevant aggravation if her symptoms have increased and become more serious.
I accept that the applicant’s symptoms have increased and become more serious as a result of her employment; and those symptoms are ongoing. In addition to the applicant’s evidence of increasing pain and symptoms at work, there is the evidence of Dr Gschwind of her lack of satisfaction with the applicant’s progress and the long duration of her symptoms. Dr Wajon did not doubt that her work tasks aggravated her symptoms. Dr Machart recorded pain of increasing severity; and aggravation through work practices caused the condition to be symptomatic. Prof Cumming accepted that the nature of the applicant’s employment and the specific tasks were an aggravating factor on a symptomatic basis (as were activities outside the workplace).
The medical evidence supports the proposition that the aggravation is ongoing; and the applicant now requires surgery, which the respondent concedes is an appropriate form of treatment.
Prof Cumming opined that the applicant’s work activities did not cause her condition or alter its pathology when she carried them out. There was a range of activities both at work and outside the workplace that were painful, but it was not determined that each activity altered the pathology. The symptoms, such as pain, (which he accepted the applicant had) were a warning that the pathology was significant, but the activity at work had not produced a change in pathology.
Prof Cumming opined that the “quite right” question was whether the applicant’s actions at work caused her to develop pathology. That may be the right question if one is considering a section 4(b)(i) injury, but not when one is considering a section 4(b)(ii) injury.
Prof Cumming’s opinion that there was no pathological change as a result of the applicant’s employment has influenced his conclusion that she has not sustained an injury. As has been made clear, that is not the basis on which such a decision is to be made.

Dr Machart’s opinion has varied as to whether the applicant contracted osteoarthritis in the course of her employment, or whether her employment aggravated the disease. However, as the applicant submitted, he appears to have “come back to” a section 4(b)(ii) injury. She submits that he has done that in also supporting a section 4(b)(i) injury.
In my view, Dr Machart’s evidence is more supportive of a section 4(b)(ii) injury. He opined that aggravation through work practices caused the condition to be symptomatic. In expressing this opinion, he did not fall into Prof Cumming’s error of considering whether the applicant’s employment was responsible for any change in the pathology of her condition. He also opined that the aggravation was ongoing.
The applicant certainly experienced pain with other pinching or grasping activities and gave up tennis because she had insufficient strength in her hands while wearing her splints. However, the fact that she had pain with other activities does not mean that her condition was not aggravated by her employment, or that the work-related aggravation was not ongoing.
The next issue to be considered is whether the applicant’s employment was the main contributing factor to the aggravation of the disease.
The definition of “main contributing factor” was discussed at length in AV v AW [2020] NSWWCCPD 9 at [65]-[78].
Deputy President Snell discussed the previous authorities, including Flanagan v NSW PoliceForce [2017] NSWWCCPD 33; State Transit Authority of New South Wales v El-Achi [2015] NSWWCCPD 71; Mannie v Bauer Media Pty Ltd [2016] NSWWCCPD 47; and Lilyvale Hotel Pty Limited v Bradley [2016] NSWWCCPD 62. He summarised the discussion as follows:
“It follows that the test of ‘main contributing factor’ involves consideration of whether there were competing causal factors (both work and non-work related) of the aggravation, and whether on a consideration of relevant causal factors the employment represented the main contributing factor.

The following may be taken from the above:

(a)The test of ‘main contributing factor’ in s 4(b)(ii) is more stringent than that in s 4(b)(ii) in its previous form, which applied in conjunction with the test in s 9A. There will be one ‘main contributing factor’ to an alleged aggravation injury.

(b)The test of ‘main contributing factor’ is one of causation. It involves consideration of the evidence overall, it is not purely a medical question. It involves an evaluative process, considering the causal factors to the aggravation, both work and non-work related. Medical evidence to address the ultimate question of whether the test of ‘main contributing factor’ is satisfied is both relevant and desirable. Its absence is not necessarily fatal, as satisfaction of the test is to be considered on the whole of the evidence.

(c)In a matter involving s 4(b)(ii) it is necessary that the employment be the main contributing factor to the aggravation, not to the underlying disease process as a whole.” (at [77]-[78]).
As Snell DP found, the issue of “main contributing factor” is not purely a medical question. Both Dr Machart and Prof Cumming have provided an opinion as to whether the applicant’s employment with the respondent was the main contributing factor to the aggravation of the disease. Prof Cumming, of course, does not accept that her employment aggravated the disease in any event.
Once again, it is necessary to refer to the applicant’s comprehensive evidence about what her work for the respondent actually entailed. She estimated she made 80 to 100 adjustments of infusions per day. Many of her tasks involved use of her thumbs. While she would of course be required to use her thumbs for domestic tasks and activities of daily living, it is unlikely that she would be required to, for example, use a screwdriver, pinch a key, open a jar, drive, put on her clothing, or make a cup of tea as often as she was required to perform her work activities.
The applicant’s evidence is that she ceased doing ceramics or basket weaving many years ago and she gave up tennis because she was wearing splints that made her an ineffective player. She said in her oral evidence that she stopped playing tennis at the end of 2017 or beginning of 2018. She told Prof Cumming in April 2018 that she had ceased playing tennis.
Prof Cumming’s opinion as to “main contributing factor” appears to have been influenced by his opinion that the applicant’s condition is constitutional, and its causation is irrelevant. He also opined that her employment was not the main contributing factor to any increase in pathology in her thumb base. Once again, that is not the issue. The issue is whether the applicant’s employment was the main contributing factor to the aggravation of the disease. It did not have to have to be the main contributing factor to an increase in her pathology.
Dr Machart opined that the applicant’s employment was the main and only contributing factor to the aggravation of her disease. It is of course not necessary that employment be the only contributing factor, but his opinion strongly supports the applicant. I prefer his opinion, as he has more accurately addressed the issue; and in considering the whole of the evidence I am satisfied that the applicant’s employment with the respondent was the main contributing factor to the aggravation of the disease of osteoarthritis.
The parties have agreed that, if the applicant is successful in her claim, then she should be awarded weekly benefits compensation at the rate of $100 per week pursuant to sections 36 and 37 of the 1987 Act. She amended the Application to claim weekly benefits from 1 February 2018 to 1 August 2020. The period of 130 weeks, during which weekly benefits are payable pursuant to sections 36 and 37 of the 1987 Act, expired on 30 July 2020.
I will make an award of weekly benefits pursuant to sections 36 and 37 of the 1987 Act to 30 July 2020 and give the parties liberty to apply with respect to the award.
There will be an award for the applicant pursuant to section 60 of the 1987 Act with respect to past medical expenses.
The respondent having conceded that the proposed surgery is reasonable and medically necessary to treat the applicant’s condition, there will be an award in her favour pursuant to section 60 of the 1987 Act for the cost of surgery to both thumbs, being a resection of the trapezium and suspension arthroplasty.

Kerry Haddock
MEMBER

22 April 2021

CaseChat Overview and Summary

Orders of the court

Background to the litigation

Evidence Before The Court

Reasons for decision

Legal Principle Established