Does the length of incision in the quadriceps affect the recovery of strength after total knee replacement?

This prospective randomised clinical trial by K. Chareancholvanich, MD, and C. Pornrattanamaneewong, MD, from Siriraj Hospital, Department of Orthopaedic Surgery, Mahidol University, Bangkok, Thailand was short and interesting.
(Bone Joint J 2014 – 96B)

They compared the time to recovery of quadriceps strength after total knee replacement (TKR) using three different lengths of incision in the quadriceps. 60 patients were randomly divided in to three groups according to the length of incision in the quadriceps above the upper border of the patella – 2 cm, 4 cm or 6 cm. The quadriceps strength was measured pre-operatively and every month post-operatively until the peak quadriceps torque returned to its pre-operative level.

All other parameters were the same in the 3 groups – mean operating time, blood loss, hospital stay, alignment or pre-operative quadriceps strength. Using the Kaplan–Meier method, group A had a similar mean recovery time to group B (2.0 ± 0.2 vs 2.5 ± 0.2 months, p = 0.176). Group C required a significantly longer recovery time (3.4 ± 0.3 months) than the other groups (p < 0.03). However, there were no significant differences in the mean Oxford knee scores one year post-operatively between the groups. They concluded that an incision of up to 4 cm in the quadriceps did not delay the recovery of its isokinetic strength but anything over 6 cms delayed the recovery of strength after TKR.