Knee manipulation for reduced flexion after Total Knee Arthroplasty. Is timing critical?

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.

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.

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).

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.