Clinical Negligence - Expert Witness Case

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On 20 June 2022, professional footballer Roger Johnson’s high-profile claim against specialist knee surgeon, Andrew Williams, was heard by the High Court (Queen’s Bench Division). The Roger Johnson v Andrew Williams [2022] EWHC 1585 (QB) judgment contains invaluable commentary on the analysis of expert evidence, providing key learnings for expert witnesses. 


In January 2017, the Claimant,  Roger Johnson (C), suffered a left knee meniscal tear whilst training. The Defendant, Andrew Williams (D), a specialist knee surgeon, performed a synovectomy on 31 January to treat the tear. The surgery appeared to have gone well. However, C developed an infection in his knee, which required further surgery on 17 March to remove infected material.

Unfortunately, C suffered with a tear/rupture to his medial retinaculum, a tendon that crosses the inner side of the knee joint. According to C, the evidence for such damage was twofold.  First, a fluid-filled egg-shaped lump, which appeared on the medial left knee a few days after surgery and persisted despite repeated aspirations on 27 and 30 March and 6 April. Secondly, a 3cm diameter tear, which was shown on an MRI scan on 11 April (25 days after surgery).

C claimed the only possible and likely cause of the medial retinaculum tear was surgical error on 17 March. D’s explanations – of infection weakening the retinaculum and C’s failure to follow post-operative instructions – were so remotely unlikely they could be rejected.

D asserted the damage occurred after the surgery, probably after an ultrasound scan on 27 March.

The Issue

There was a single issue for the Court to consider and determine: did D cause a large tear in C’s medial retinaculum on 17 March 2017 in the course of the surgery? D accepted that, if he did cause such damage without noticing and repairing it during surgery, he would have been negligent. 

The Factual Evidence

The operation note from 17 March recorded “excellent views”. D had not recorded he had seen any tear to the retinaculum, nor any extravasation of fluid from a tear.

On 19 March, D performed a left knee wash-out. Again, good views were obtained and, again, no defect or fluid extravasation was recorded.

On 21 March, some moderate medial left knee swelling was noted. Following discharge, a home-visit physiotherapy note on 23 March suggested C was not complying with post-operative instructions.

Between 23 and 25 March, an egg-shaped lump was noted on the knee.

On 27 March, this lump, a haematoma, was aspirated under ultrasound guidance. The radiologist reported a separate effusion in the knee joint but no damage to the retinaculum. This effusion was aspirated separately to the haematoma.

On 30 March, D aspirated the extracapsular haemarthrosis in the knee joint, which he thought had been caused by small vessel damage intra-operatively.

On 3 April, the physiotherapist again documented concern with C’s compliance with instructions.

On 6 April, a further aspiration took place of the lump and on 11 April an MRI was performed. This revealed the 3cm medial retinaculum tear, with fluid which had herniated into a subcutaneous fluid collection with communication between the intra-articular space and extra-capsular region.

The Expert Evidence

In analysing the expert evidence, the judge reminded himself of C v North Cumbria University Hospitals NHS Trust [2014] EWHC 61, specifically but not limited to:

  • The need for expert evidence to be “tendered in good faith”;
  • “Whether the expert is "responsible", "competent" and/or respectable”; and,
  • “Whether the opinion is reasonable and logical”.

The orthopaedic experts agreed in their Joint Statement that causing a large rupture to the medial retinaculum, whilst possible, was “an extremely rare and unusual complication following synovectomy”.

The claimant’s expert

C relied upon Mr Ashok Paul. His CV made the claim that he had been “the Manchester United Orthopaedic Surgeon for 20 years”. However, after extensive cross-examination on the point, it was apparent he was not, and never had been, the exclusive surgeon for Manchester United. He had done some work for the club but had never been employed by them and there were other surgeons who also did orthopaedic work. The judge considered that, “Such concessions extracted only after repeated questions highlighted a theme of his evidence which was a degree of overstatement and inflexibility with respect to the views he expressed...”

Mr Paul accepted that such a tear was very rare and would usually be obvious immediately, although he asserted it could still occur in “some cases”. Under cross-examination, it became apparent that those “some cases” were neither in the literature nor in Mr Paul’s own personal experience, and his statement was based on the fact it had happened in this case.

Mr Paul asserted that there was no possible other explanation than negligence - “absolutely none” - even though he could not adequately explain why the tear had not been seen immediately or during the subsequent washout, why there was no evidence D had used excessive force and why no immediate swelling had occurred.

The judge considered that Mr Paul’s assertion, namely the fact the injury had happened meant D must have missed it and every other explanation was impossible, was “far too extreme and inflexible a position for such an unusual complication” and that none of his partial explanations “were compelling either as a matter of opinion or logic”.

The defendant’s expert

D relied upon Mr Anand. The judge found him to be “more balanced and cautious” in his view that the tear occurred after the surgery, otherwise it would have been seen at surgery or extravasated fluid would have been seen during the subsequent washout under pressure.

Nevertheless, there were some aspects of his evidence that were less than satisfactory. For example, a change in position between his report and trial as to the date of when the rupture occurred. The judge considered that this “did undermine both the credibility and reliability of some of [his] evidence”. The judge found against him (and D) on the point that the radiologist’s report on 27 March was conclusive proof that there was no communication between the haematoma and the knee joint at that point.

The Judgment

The judge concluded that at least some tear had occurred before 23/24 March, when the egg-shaped lump appeared, and even before 21 March, when the medial knee swelling was first noticed. However, that did not mean that a large rupture had occurred during surgery, because:

  • D would have had to have used excessive force repeatedly to cause such a large hole;
  • it would have been immediately apparent;
  • to fail to see it would suggest a “high degree of inadvertence”;
  • fluid would have extravasated immediately from the hole;
  • swelling would have occurred between 18-20 March when the drains had been removed; and,
  • there was no extravasation during the high pressure wash-out on 19 March.

All of these meant it was “highly improbable” that D had caused the large hole at surgery, although it was not impossible.

As such, “the evidence adduced by the Claimant and his expert has not been sufficiently cogent or compelling to allow me to conclude on the balance of probabilities that the Defendant caused a 3cm diameter defect to the Claimant’s medial retinaculum on 17th March 2017 in the course of the synovectomy procedure”. 

The Conclusion

The judgment is yet another of many that quotes and applies key passages from Green J.’s judgment in the C v North Cumbria case in 2014 with respect to the analysis of expert evidence.

It emphasises the importance of experts not being inflexible, not overstating matters, not adopting extreme positions, not changing their opinion at trial (certainly if no new evidence has emerged to justify that change) and, most importantly, having an opinion that is logical.

Author: Dr Jock Mackenzie