Michael Murphy1, Simon Journeaux2, Julie Hides3, Trevor Russell4. 1. Mater Medical Research Institute, Mater Health Services, Raymond Terrace, South Brisbane, Australia, 4101. Electronic address: michael.murphy@mater.org.au. 2. School of Health and Rehabilitation Science, University of Queensland, St Lucia, Australia, 4076. 3. Faculty of Health Sciences, Australian Catholic University, Banyo, Australia, 4014. 4. Mater Medical Research Institute, Mater Health Services, Raymond Terrace, South Brisbane, Australia, 4101.
Abstract
INTRODUCTION: Prosthetic and operative modifications in total knee arthroplasty (TKA) have been proposed to maximise post-operative knee flexion as it is essential in routine functional activities. METHODS: We performed a double blind randomised controlled trial to compare clinical outcomes of primary cruciate-retaining TKA for osteoarthritis with the femoral component implanted in either 4° flexion in the sagittal plane (F) or in a neutral position (C). The primary outcome of knee flexion and secondary outcomes knee extension, quadriceps strength, WOMAC, SF-12v2, timed stand test, stair climb test and satisfaction were assessed at 1 year. Knee flexion and extension were also assessed intra-operatively. Implant flexion was measured from true lateral radiographs. RESULTS:Thirty-nine participants (40 knees) were recruited, 20 knees per group. Three subjects from the control group and two from the flexed group were lost to 1 year follow-up but numbers were sufficient to satisfy the sample size calculation. Significant differences were found between the groups in knee flexion (F: 113.6±8.8° pre-operative, 122.4±6.0° intra-operative, 110.2±7.5° 1 year, C: 117.4±11.7°, 117.4±7.6°, 103.5±10.7°. p=0.031) and mental component score of the SF12-v2 (F 53.3±13.2, C 61.1±7.3, p=0.009) but there were no significant differences in other outcomes and patients were equally satisfied. CONCLUSION: Flexing the femoral implant in this cruciate retaining TKA system provided a significant difference in knee flexion compared to a neutral position. The improvement appears to occur predominantly at surgery and was not associated with a clinical or functional benefit at 1 year. (ACTRN12606000325505). LEVEL OF EVIDENCE: Level 1; randomised controlled trial.
RCT Entities:
INTRODUCTION: Prosthetic and operative modifications in total knee arthroplasty (TKA) have been proposed to maximise post-operative knee flexion as it is essential in routine functional activities. METHODS: We performed a double blind randomised controlled trial to compare clinical outcomes of primary cruciate-retaining TKA for osteoarthritis with the femoral component implanted in either 4° flexion in the sagittal plane (F) or in a neutral position (C). The primary outcome of knee flexion and secondary outcomes knee extension, quadriceps strength, WOMAC, SF-12v2, timed stand test, stair climb test and satisfaction were assessed at 1 year. Knee flexion and extension were also assessed intra-operatively. Implant flexion was measured from true lateral radiographs. RESULTS: Thirty-nine participants (40 knees) were recruited, 20 knees per group. Three subjects from the control group and two from the flexed group were lost to 1 year follow-up but numbers were sufficient to satisfy the sample size calculation. Significant differences were found between the groups in knee flexion (F: 113.6±8.8° pre-operative, 122.4±6.0° intra-operative, 110.2±7.5° 1 year, C: 117.4±11.7°, 117.4±7.6°, 103.5±10.7°. p=0.031) and mental component score of the SF12-v2 (F 53.3±13.2, C 61.1±7.3, p=0.009) but there were no significant differences in other outcomes and patients were equally satisfied. CONCLUSION: Flexing the femoral implant in this cruciate retaining TKA system provided a significant difference in knee flexion compared to a neutral position. The improvement appears to occur predominantly at surgery and was not associated with a clinical or functional benefit at 1 year. (ACTRN12606000325505). LEVEL OF EVIDENCE: Level 1; randomised controlled trial.
Authors: Marco A Marra; Marta Strzelczak; Petra J C Heesterbeek; Sebastiaan A W van de Groes; Dennis Janssen; Bart F J M Koopman; Nico Verdonschot; Ate B Wymenga Journal: Knee Surg Sports Traumatol Arthrosc Date: 2018-03-20 Impact factor: 4.342