Pullen v Basildon and Thurrock University Hospitals NHS Foundation Trust

In a clinical negligence claim, the claimant must prove the most likely causal mechanism before breach of duty can be assessed. Where experts disagree, the court must evaluate and explain why it prefers one opinion, rather than treating compliance with the Bolam test as conclusive. A secure acetabular fixation is required, and failure to perform the fixation test within an acceptable range of force may constitute negligent technique even where the surgeon is competent and unaware of the error. A subsequent dislocation will not displace that conclusion where the evidence makes alternative post-operative causes remote.

The claimant alleged that an acetabular cup loosened during or immediately after total hip replacement surgery, causing an anterior dislocation and requiring revision surgery. The defendant accepted that damages were £37,500, subject to liability.

The central issues were whether the cup was inadequately fixed during the operation or became loose because of a subsequent event, and, if fixation was inadequate, whether the surgical technique fell below the required standard of care.

1. Liability established. Judgment was entered for the claimant for the agreed sum of £37,500.
2. The claimant bore the burden of proving, on the balance of probabilities, the causal mechanism by which the cup loosened. The court had to determine that issue before considering breach, since no breach arose if the cup had loosened through an unrelated post-operative event.
3. The court accepted the radiological and factual evidence that the hip had dislocated anteriorly. The claimant experienced instability and popping immediately when mobilisation began. The later finding that the cup was excessively anteverted and could be removed with little pressure supported the conclusion that the cup had loosened before the dislocation.
4. The suggested alternatives—obesity, abnormal leg movement, haematoma and soft-tissue impingement—were remote or unsupported. They did not explain the timing, direction or circumstances of the dislocation.
5. Although the surgeon was experienced and had recorded an excellent press fit, the fixation test could have involved either excessive or insufficient force. Excessive force could loosen the cup, while insufficient force could fail to reveal inadequate fixation. Either possibility represented a technique below an acceptable standard. The finding did not imply that the surgeon was generally incompetent or knowingly permitted substandard surgery.
6. In addressing the conflict between the experts, the court applied the guidance in Smith v Southampton University Hospital NHS Trust [2007] EWCA Civ 387: it was necessary to explain why one expert’s evidence was preferred, rather than simply invoke the range of responsible medical opinion.

The parties were invited to agree consequential orders, with written submissions to follow if agreement was not reached.