Comparison of postoperative isokinetic quadriceps and gluteal muscular strength after primary THA: is there an early benefit through enhanced recovery programs?

PURPOSE: Although total hip arthroplasty (THA) is expected to result in a postoperative loss of muscular strength, no study investigated the benefit of an enhanced-recovery-after-surgery (ERAS) concept on the hip muscles in detail. We evaluated if (1) an ERAS-concept for primary THA results in reduced loss of muscular strength five days and four weeks postoperative. We (2) compared the two groups regarding Patient-Related-Outcome-Measures (PROMs), WOMAC-index (Western-Ontario-and-McMaster-Universities-Osteoarthritis-Index), HHS (Harris-Hip-Score) and EQ-5d-3L-score. METHODS: In a prospective, single-blinded, randomized controlled trial, we compared isokinetic muscular strength of 24 patients receiving primary THA with an enhanced recovery concept with early mobilization (n = 12, ERAS-group) and such receiving conventional THA (n = 12, non-ERAS). Isokinetic muscular strength was measured with a Biodex-Dynamometer before, as well as five days and four weeks after surgery (peak-torque, total-work, power). Furthermore, WOMAC, HHS, PROMs and EQ-5d-3L were imposed. RESULTS: The ERAS group revealed significant higher isokinetic strength (peak-torque, total-work, power) at both time points. Both groups showed a significant pain decrease at both time points meeting very high rates of patient satisfaction resembled by good results in PROMs, WOMAC, HHS, EQ-5d. There was no significant difference in any of the scores between both groups. CONCLUSION: We proved a significant reduced loss of muscular strength five days and four weeks after primary THA in combination with an ERAS concept. However, the reduced loss of muscular strength is not reflected by patient’s functional outcome and quality of life, showing no significant differences in WOMAC, HHS, EQ-5d-3L, PROMs and NRS. Therefore, this study supports the implementation of an ERAS concept for primary THA in terms of isokinetic strength. Further studies are needed to evaluate the development of muscular strength over a long period.