Muscle recovery following knee arthroplasty

Investigators assessed changes in quadriceps and hamstring strength and flexibility through 12 months following total knee arthroplasty.

To evaluate quadriceps and hamstring strength and flexibility changes following total knee arthroplasty over a 12-month period.

Study Design: A prospective, longitudinal single-center study involving patients aged 50 to 80 years with severe knee osteoarthritis scheduled for total knee arthroplasty.
Participants: 77 patients were enrolled, with follow-up completed by 77 at 6 weeks and 3 months, 54 at 6 months, and 26 at 12 months.
Assessment Methods: Quadriceps and hamstring strength were evaluated using handheld dynamometry, and flexibility was assessed through passive knee extension and a modified Thomas test.
Rehabilitation Program: Patients underwent a standardized postoperative rehabilitation program including progressive strengthening, mobility, stretching, functional training, balance training, and aerobic conditioning.

Mean quadriceps strength decreased from 12 lbs preoperatively to 7 lbs at 6 weeks, then increased to 30 lbs at 3 months, 38 lbs at 6 months, and 43 lbs at 12 months.
Mean hamstring strength decreased from 20 lbs preoperatively to 13 lbs at 6 weeks, then increased to 30 lbs at 3 months, 42 lbs at 6 months, and 58 lbs at 12 months.
At 12 months, quadriceps and hamstring strength remained lower compared with control values of 75 lbs and 68 lbs, respectively.

Attrition at 12 months may limit generalizability.
Absence of blinded outcome assessment may introduce bias.
Analysis did not account for postoperative pain, rehabilitation adherence, or physical activity.