Background: Reduced flexion following knee arthroplasty (TKA) may compromise patient's function and outcome. The timing of manipulation under anaesthesia (MUA) has been controversial. We present our experience in a high volume practice and analyse the impact of timing.
Methods: All TKA patients requiring MUA from February 1996 to June 2015 under the care of a single surgeon were analysed. MUA was offered to patients who had ≤ 75° of flexion post-op, providing that they had 30° more flexion preoperatively. To address the impact of timing from primary surgery to MUA on flexion gain we looked at 3 groups: Group I ≤ 90 days, Group II 91-180 days and Group III > 180 days.
Results: Sixty two out of 7,423 (0.84%) underwent MUA. The MUA patients were significantly younger than the overall TKA cohort 61.2 vs 70.5 years (p = < 0.01). The median duration between arthroplasty and MUA was 3.9 months (IQR 3.4, Range 1.6-72.5 months). Overall flexion gained at 6-12 Weeks and 1 year post MUA showed significant improvements of 20.9° (p = <0.01) and 25° respectively (p = < 0.01). The flexion gain in group I (≤ 90 days) was significantly better than group III ( > 180 days) both at 6 weeks and 1 year following MUA but not better than group II (90-180 days).
Conclusions: MUA is an effective treatment for reduced flexion following TKA and should be the first line of management after failed physiotherapy. It can still have benefit beyond 6 months but the gains become less effective with time.
Keywords: Arthroplasty; Knee; Manipulation; Reduced flexion; Timing.