Manipulation under anaesthesia post total knee replacement: long term follow up

A reduced range of motion post total knee replacement (TKR) is a recognised problem. Manipulation under anaesthesia (MUA) is commonly performed in the stiff post-operative TKR. Long-term results are variable in the literature. We retrospectively reviewed, prospectively collected data on 48 patients followed up since 1996 from one centre, over an average of 7.5 years, (range 1 to 10 years) and report on the long-term results. During the study period 2.3% of TKRs underwent MUA. The mean time to MUA post TKR was 12.3 weeks (range 3 to 48). Pre MUA, the mean flexion was 53°. The mean immediate passive flexion post MUA was 97°, an improvement of 44° (Range 10° to 90°, p<0.05). By 1year, the mean flexion was 87°, an improvement of 34°, (range -15° to 70°, p<0.05). At 10 years the mean flexion was 86°, (range 55° to 100°, p<0.05). We found no difference in the gain in range of motion (ROM) between knees manipulated before or after 12 weeks. Additionally, the gain was no different in stiff knees with a pre TKR ROM <90°, compared to a pre TKR ROM >90°. There were no complications as a result of MUA. However, one patient was eventually revised at 2 years secondary to low grade infection. Our findings show that MUA is a safe and effective method at improving the ROM in a stiff post-operative TKR. The improvement is maintained in the long term irrespective of time to MUA and range of motion pre TKR.