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An expert eye

01 January 2014

Mrs K was 58 when she saw Mr B, a consultant orthopaedic surgeon, because of her right hip pain. She was finding walking difficult and suffered with night pain: both common symptoms of osteoarthritis. The x-rays only showed mild degenerative changes and Mr B felt it was too early in the course of the disease for an operation.

However, Mrs K’s symptoms worsened and three years later she returned for another consultation. Mr B now felt that a total hip replacement was indicated and Mrs K consented to surgery. Prior to surgery he explained the benefits and risks of a hip replacement. Complications, including a change in leg length, were discussed, though this was not specifically documented on the consent form. Mrs K understood that she should hopefully be pain-free within two months of surgery and go on to make a full recovery by six months post-surgery.

At surgery, several different component sizes of the femoral neck and head were trialled. The final implant was chosen to ensure appropriate soft tissue tension, in order to ensure maximum stability of the hip and minimise the risk of dislocation.

The operation went well and there were no postoperative problems. Mrs K was recovering as expected when she was seen for review at one month. After three months, however, she complained of discomfort over the lateral aspect of her hip. An x-ray showed that her right leg was 9mm longer than her left, but Mr B felt a shoe raise was not indicated. This lateral pain persisted though, and Mrs K was provided with a shoe raise to equalise the leg lengths at a further review.

Mrs K sought a CT scan, which confirmed the leg length discrepancy, and she also had injections in her lumbar spine for pain relief, which did not help. Due to these ongoing problems Mr B organised an aspiration of her right hip replacement, which did not show any evidence of infection, and also referred her to Mr L, an expert in revision hip surgery, for a second opinion.

After reviewing the history of ongoing pain post-surgery, a clinical examination and a new set of x-rays, Mr L could not see any obvious problem with the hip replacement that would account for her symptoms. Mr L explained to Mrs K that the hip was “only very slightly long”. He felt that maybe she was getting some impingement pain from her psoas tendon.

Mrs K was becoming increasingly frustrated and upset, believing that her problems all stemmed from an increase in her leg length, and returned to see Mr B again. She enquired whether further surgery might resolve the pain. Mr B, as well as obtaining a second opinion from Mr L, had discussed the case with other colleagues.

They agreed that a 1cm leg length discrepancy should not cause such problems, and that even lengthening by 3 to 4cm is regularly tolerated well by patients. He advised against further surgery, as did his colleagues, but he organised an MRI scan of the hip and spine to try and find a source of Mrs K’s pain.

The MRI showed some degenerative changes in her lumbar spine and also a ‘hot spot’ around the total hip replacement indicating, once again, the possibility of an infection. Another hip aspiration was arranged. For a second time the aspiration grew no organisms on culture, which confirmed that an infection was most unlikely. Mr B also reiterated his view that Mrs K’s leg length discrepancy was minimal.

Mrs K was now finding walking for more than an hour impossible. After five minutes she developed steadily worsening pain in her hip, and she struggled with stairs. She brought a claim against Mr B, citing a leg length discrepancy of two and a half centimetres, and failure to plan and perform the surgery adequately.

Mr B denied negligence and the experts involved upheld this. There was only minimal leg length discrepancy, less than had been claimed, and it is a recognised complication. Mr B performed both the surgery and subsequent investigations in an appropriate manner, and sought a second opinion from an expert. The claim was discontinued.

Learning points

  • Limb length discrepancy is the second most common cause of litigation in arthroplasty surgery, behind nerve injury.1
  • Approximately 15% of hip replacement surgery results in a limb length discrepancy. Less than 1cm discrepancy2 is the ideal goal,3 but up to 2cm is reported to be tolerable by patients.4
  • The importance of good documentation concerning consent of all common and serious complications is vital. Specific complications should be included on the consent form. In this case limb length discrepancy was discussed with the patient and mentioned in the GP letter.
  • Explaining to a patient why a complication might arise helps them to understand and accept it if it happens. In this case, having a stable hip replacement and adequately tensioned soft tissues is more important than a leg length discrepancy, and should be emphasised.
  • This case highlights the importance of having strong experts. In this case, expert opinion found some of Mrs K’s claims inaccurate and found Mr B had dealt with the patient in an appropriate manner. MPS robustly defends non-negligent claims.

References

  1. Upadhyay A, York S, Macaulay W et al, Medical malpractice in hip and knee arthroplasty, J Arthroplasty 22(6 Suppl 2):2-7, 2007
  2. Briggs T, Miles J, Aston W (eds), Operative Orthopaedics: The Stanmore Guide, Chapter: Surgery of the Hip. Miles J, Skinner J (chapter editors)
  3. Ranawat CS, Rodriguez JA., Functional leg-length inequality following total hip arthroplasty, J Arthroplasty 12(4):359-64, 1997
  4. Vitale MA, Choe JC, Sesko AM et al, The effect of limb length discrepancy on health-related quality of life: Is the ‘2 cm rule’ appropriate? J Pediatr Orthop B 15(1):1-5, 2006