Purpose: A stiff total knee replacement can severely limit a patient's post-operative function, but there remain few prospective trials identifying those patients at risk, nor the efficacy of manipulation. We analysed our prospectively collected database to assess predictors of stiffness and outcomes following manipulation.
Methods: Using prospectively collected knee arthroplasty data, including preoperative and post-operative range of knee movement, SF-12 (physical and mental) and The Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores, patients requiring manipulation were compared to a matched group of patients not requiring manipulation, with a detailed statistical analysis undertaken to assess potential risk factors and the post-manipulation outcome.
Results: Of the 1313 arthroplasty patients, 69 required manipulation. Patients with less than 80° of flexion at discharge, diabetes or on warfarin were more likely to require manipulation, but flexion at discharge was the overwhelming predictive factor for stiffness. Forty per cent of the range of movement gained during manipulation was maintained at 1 year, with earlier manipulation deriving greater improvements. While the WOMAC scores improved post-manipulation, there was no significant difference in either of the SF12 scores.
Conclusion: Flexion at discharge is the overwhelming predictive factor for the requirement for manipulation.
Keywords: knee; knee replacement; manipulation under anaesthesia; stiffness.