Muscular strength after total hip arthroplasty: A prospective comparison of 3 surgical approaches

ResultsDifferences in maximal strength change were greatest after 2 and 8 days. The posterior and anterior approaches produced less decrease in muscular strength than the direct lateral approach. 6 weeks postoperatively, the posterior approach produced greater increase in muscular strength than the direct lateral approach, and resulted in a greater increase in abduction strength than the anterior approach. At 3-month follow-up, no statistically significant differences between the groups were found. The operated legs were 18% weaker in leg press and 15% weaker in abduction than the unoperated legs, and the results were similar between groups.InterpretationThe posterior and anterior approaches appeared to have the least negative effect on abduction and leg press muscular strength in the first postoperative week; the posterior approach had the least negative effect, even up to 6 weeks postoperatively. THA patients have reduced muscle strength in the operated leg (compared to the unoperated leg) 3 months after surgery.Regaining muscular strength is important for postoperative function after hip arthroplasty. Inactivity reduces muscular strength and physical function (McGuire et al. 2001, Suesada et al. 2007, Kortebein et al. 2008), and muscular strength decreases substantially in the first week after total hip arthroplasty (THA) (Holm et al. 2013). Early recovery and rehabilitation of the weakened musculature is therefore of importance (Sicard-Rosenbaum et al. 2002). The type of surgical approach used has a major impact on THA stability and muscle function (Masonis and Bourne 2002).The direct lateral approach (DLA) is associated with a low dislocation risk (Witzleb et al. 2009), but of concern is that it traumatizes the abductor muscles, which can lead to permanent postoperative limp and weakness (Edmunds and Boscainos 2011). The posterior approach (PA) has been associated with postoperative dislocations (Edmunds and Boscainos 2011, Brooks 2013), mainly owing to the small femoral heads used to prevent wear (Bystrom et al. 2003). However, the introduction of highly cross-linked polyethylene into the articulation has reduced wear independently of head diameter (Bragdon et al. 2007), leading to increased use of larger head diameters (Lombardi et al. 2011). It has also been shown that a posterior soft-tissue repair following PA reduces the dislocation rate (van Stralen et al. 2003, Suh et al. 2004). The anterior approach (AA), first described by Robert Judet in 1947 as a modified Smith-Petersen approach, follows the principles of minimally invasive surgery. This approach provides intermuscular and internervous exposure to the hip (Wojciechowski et al. 2007), leading to reduced soft-tissue dissection and trauma (Bergin et al. 2011). Concerns have been related to higher complication rates owing to wound complications, intraoperative fracture, and compromised fixation after minimally invasive surgery, with increased risks of early revision surgery (Graw et al. 2010).There is no consensus on the relative functional advantages of different surgical approaches (Gulati et al. 2008, Edmunds and Boscainos 2011), and differences in maximal strength have not been examined. To our knowledge, there have been no studies comparing the DLA, the PA, and the AA in terms of early maximal muscular strength. We compared these 3 surgical approaches with regard to regaining of maximal muscular strength by 3 months postoperatively in patients undergoing THA.