Strengthening of the Hip and Core Versus Knee Muscles for the Treatment of Patellofemoral Pain: A Multicenter Randomized Controlled Trial

Abstract

Context: Patellofemoral pain (PFP) is the most common injury in running and jumping athletes. Randomized controlled trials suggest that incorporating hip and core strengthening (HIP) with knee-focused rehabilitation (KNEE) improves PFP outcomes. However, no randomized controlled trials have, to our knowledge, directly compared HIP and KNEE programs.Objective: To compare PFP pain, function, hip-and kneemuscle strength, and core endurance between KNEE and HIP protocols after 6 weeks of rehabilitation. We hypothesized greater improvements in (1) pain and function, (2) hip strength and core endurance for patients with PFP involved in the HIP protocol, and (3) knee strength for patients involved in the KNEE protocol.Design: Randomized controlled clinical trial. Setting: Four clinical research laboratories in Calgary, Alberta; Chicago, Illinois; Milwaukee, Wisconsin; and Augusta, Georgia.Patients or Other Participants: Of 721 patients with PFP screened, 199 (27.6%) met the inclusion criteria (66 men [31.2%], 133 women [66.8%], age ¼ 29.0 6 7.1 years, height ¼ 170.4 6 9.4 cm, weight ¼ 67.6 6 13.5 kg).Intervention(s): Patients with PFP were randomly assigned to a 6-week KNEE or HIP protocol.Main Outcome Measure(s): Primary variables were selfreported visual analog scale and Anterior Knee Pain Scale measures, which were conducted weekly. Secondary variables were muscle strength and core endurance measured at baseline and at 6 weeks.Results: Compared with baseline, both the visual analog scale and the Anterior Knee Pain Scale improved for patients with PFP in both the HIP and KNEE protocols (P , .001), but the visual analog scale scores for those in the HIP protocol were reduced 1 week earlier than in the KNEE group. Both groups increased in strength (P , .001), but those in the HIP protocol gained more in hip-abductor (P ¼ .01) and -extensor (P ¼ .01) strength and posterior core endurance (P ¼ .05) compared with the KNEE group.Conclusions: Both the HIP and KNEE rehabilitation protocols produced improvements in PFP, function, and strength over 6 weeks. Although outcomes were similar, the HIP protocol resulted in earlier resolution of pain and greater overall gains in strength compared with the KNEE protocol.

Hip and Knee Strengthening Is More Effective Than Knee Strengthening Alone for Reducing Pain and Improving Activity in Individuals With Patellofemoral Pain: A Systematic Review With Meta-analysis

“…7,17,21,25 Eleven trials compared hip and knee strengthening with knee strengthening alone, providing data to answer the second study question. 3,10,12,14,16,17,19,20,27,36,38 Additional information on 8 papers was requested from the authors. Quality The mean PEDro score of the trials was 5.8 (range, 3-8) (TABLE 3).…”

“…Strength The effect of hip and knee strengthening, compared with knee strengthening alone, on strength was examined by pooling postintervention data from 6 trials (n = 359) 10,12,14,19,27,38 with a mean PEDro scale score of 6.7. Hip and knee strengthening did not significantly change strength compared with knee strengthening alone (SMD, 0.2; 95% CI: -0.1, 0.4; I 2 = 0%) (FIGURE 5).…”

“…12,38 No significant change was found in strength of the hip and knee muscles between the groups 4 weeks beyond the intervention period (mean difference, 0.4 Nm/kg; 95% CI: -0.4, 1.3) 12 or 6 weeks beyond the intervention period (mean difference, -2 Nm/kg; 95% CI: -10, 6). [ research report ] activity level was examined by pooling postintervention data from 8 trials 10,12,14,16,17,19,20,38 (n = 471) with a mean PEDro scale score of 6.5. There was substantial statistical heterogeneity (I 2 = 87%).…”

The outcome of hip exercise in patellofemoral pain: A systematic review

“…www.casp-uk.net Beneficial effect of hip exercise in PFP Baldon et al, 2014Coppack et al, 2011Ferber et al, 2014Fukuda et al, 2010Fukuda et al, 2012Ismail et al,2013Nakagawa et al, 2008Dolak et al, 2011Khayambashi et al, 2012Avraham et al, 2007Boling et al, 2006Earl & Hoch 2011Ferber et al, 2011Khayambashi et al, 2014Lowry et al, 2008Mascal et al,2003Noehren et al .,2011Razheghi et al, 2010Tyler et al,2006Willy et al, 2012 No benefit of hip exercise in PFP Song et al, 2009 www.cebm.net/ocebm-levels-of-evidence…”

“…Nine trials had mixed gender groups, including two out of the three studies investigating knee versus hip protocols, which may confound the outcome as a recent study demonstrated knee extensor deficits but no hip weakness in males with PFP (Bolgla et al, 2014). Additionally, it has been shown that there are gender specific differences in hip abduction strength (Brent et al,2013;Ramskov et al, 2014), gluteal activation (Nakagawa et al, 2012) and trunk and lower limb kinematics (Nakagawa et al, 2012, Willy et al, 2012a in both the normal and PFP population.…”