Changes in total lower limb support moment in middle-aged patients undergoing arthroscopic partial meniscectomy - A longitudinal observational cohort study.

BACKGROUND: Patients with a meniscal tear are frequently treated with arthroscopic partial meniscectomy (APM) which may alter the net extension moment across the entire lower limb - known as the total support moment (TSM).

PURPOSE: To investigate changes in TSM during walking in patients undergoing APM.

METHODS: Three-dimensional motion analysis of walking was performed in individuals with meniscal tear prior to APM and 12 months after. Peak TSM, positive ankle (ASM), knee (KSM), and hip (HSM) moments at the time of peak TSM were calculated together with corresponding angular impulses.

RESULTS: Patients (n = 20) were middle aged (45.9 ± 6.3 years) and the majority male (70%). At baseline a lower KSM (mean [95%CI]; 0.59 Nm/BM · HT% [-1.93; 3.11], P = 0.048) and a trend towards lower peak TSM (0.46 Nm/BM · HT% [-1.82; 2.78], P = 0.099) were observed for the APM leg compared with the contralateral. Pre- versus post-APM change scores indicated a relative decrease in loading of the contralateral leg for peak TSM (-0.49 Nm/BM · HT% [-0.96; -0.01], P = 0.047) and a trend towards a relative increase in loading of the APM leg for peak KSM (-0.41 Nm/BM · HT% [-0.92; 0.09], P = 0.105). No differences were observed in angular impulse variables.

CONCLUSIONS: Prior to APM a strategy to unload the injured knee was manifested by reduced KSM and a tendency to a reduced peak TSM. A more equal distribution of joint moments between injured and contralateral legs was observed 12 months following APM.