BACKGROUND/ PURPOSE:Quadriceps-sparing minimally invasive total knee arthroplasty (TKA) has been proposed to limit surgical dissection without compromising surgical outcome. We conducted a prospective and randomized study to compare the outcomes of patients who underwent quadriceps-sparing TKA with the outcomes of those who underwent standard medial parapatellar TKA, after a 2-year follow-up period. METHODS:Eighty primary TKA procedures that were to be performed in 60 osteoarthritis patients were randomly assigned to either a quadriceps-sparing (40 knees) or a standard medial parapatellar (40 knees) group. All surgeries were designed to set the prosthesis with a femoral component alignment of 7° valgus and a tibial component alignment that was perpendicular to the tibial shaft. Surgical time and tourniquet time were recorded. Outcome variables included knee function, as defined by a hospital for special surgery knee score; quadriceps muscle strength, which was measured by an isokinetic dynamometer; pain, as indicated on a visual analog scale; prosthetic position, which was measured on plain radiograph; and range of motion. RESULTS:Patients who underwent the 38 quadriceps-sparing and 37 standard TKA procedures completed the 2-year follow-up period without any infection or revision. The mean surgical time and tourniquet time were significantly longer in the quadriceps-sparing group. The mean peak quadriceps muscle strength, hamstring muscle strength, normalized muscle balance (hamstring/quadriceps ratio), pain score, function score, and range of motion were comparable in both groups at 2 months and 2 years. In the quadriceps-sparing group, both the femoral and the tibial components were significantly more varus-deviated from the expected position. CONCLUSIONS: Patients undergoing quadriceps-sparing and standard medial parapatellar TKA had comparable outcomes for quadriceps muscle strength, hamstring-quadriceps balance, and knee function; however, the quadriceps-sparing TKA was more time consuming surgically and resulted in a less accurate prosthesis position.
RCT Entities:
BACKGROUND/ PURPOSE: Quadriceps-sparing minimally invasive total knee arthroplasty (TKA) has been proposed to limit surgical dissection without compromising surgical outcome. We conducted a prospective and randomized study to compare the outcomes of patients who underwent quadriceps-sparing TKA with the outcomes of those who underwent standard medial parapatellar TKA, after a 2-year follow-up period. METHODS: Eighty primary TKA procedures that were to be performed in 60 osteoarthritispatients were randomly assigned to either a quadriceps-sparing (40 knees) or a standard medial parapatellar (40 knees) group. All surgeries were designed to set the prosthesis with a femoral component alignment of 7° valgus and a tibial component alignment that was perpendicular to the tibial shaft. Surgical time and tourniquet time were recorded. Outcome variables included knee function, as defined by a hospital for special surgery knee score; quadriceps muscle strength, which was measured by an isokinetic dynamometer; pain, as indicated on a visual analog scale; prosthetic position, which was measured on plain radiograph; and range of motion. RESULTS:Patients who underwent the 38 quadriceps-sparing and 37 standard TKA procedures completed the 2-year follow-up period without any infection or revision. The mean surgical time and tourniquet time were significantly longer in the quadriceps-sparing group. The mean peak quadriceps muscle strength, hamstring muscle strength, normalized muscle balance (hamstring/quadriceps ratio), pain score, function score, and range of motion were comparable in both groups at 2 months and 2 years. In the quadriceps-sparing group, both the femoral and the tibial components were significantly more varus-deviated from the expected position. CONCLUSIONS:Patients undergoing quadriceps-sparing and standard medial parapatellar TKA had comparable outcomes for quadriceps muscle strength, hamstring-quadriceps balance, and knee function; however, the quadriceps-sparing TKA was more time consuming surgically and resulted in a less accurate prosthesis position.