Hip plus knee exercise is an effective treatment for patellofemoral pain, but hip weakness does not predict who develops it
Interpretation
Treatment evidence is consistent: 14 trials (673 participants) found hip and knee strengthening beat knee strengthening alone for pain and activity (Nascimento 2018), a 199-patient RCT found similar outcomes with faster pain relief from a hip and core protocol (Ferber 2015), and an international consensus recommends combined hip and knee exercise (Crossley 2016). Prevention evidence points the other way for hips: 18 prospective studies (4,818 participants) found hip weakness was not a risk factor (Neal 2019; Rathleff 2014), and the one large prevention trial used a mixed strengthening and stretching programme in 1,502 army recruits (Coppack 2011). Graded moderate because the treatment trials are small to mid-sized, improvements occurred without measured strength change, and no trials included triathletes.
Practical implication
Use combined hip and knee exercise, ideally guided by a physiotherapist, as a first step if knee pain develops, but don't rely on glute work alone to prevent runner's knee. Manage run-load increases and include quadriceps work. Extrapolated from recreational runners, recruits and mixed patient groups, not triathletes.
Sources
7 sources, independently verified.
Hip and knee strengthening reduced pain (MD -3.3, 95% CI -5.6 to -1.1) and improved activity (SMD 1.4) vs no training or placebo, and beat knee strengthening alone for pain (MD -1.5, -2.3 to -0.8) and activity (SMD 0.7). Benefits maintained after the intervention. Strength did not change significantly with any intervention.
Six weeks of a hip and core protocol or a knee-focused protocol: both groups improved pain, function and strength similarly; pain fell about a week earlier with the hip and core protocol, which also produced greater hip abductor and extensor strength and posterior core endurance gains.
Recommends exercise therapy for pain (short, medium and long term) and function (medium and long term), and combining hip and knee exercises over knee exercises alone; combined interventions for adults in the short and medium term; foot orthoses for short-term pain only; manual therapy and electrophysical agents not recommended; role of taping and bracing undetermined.
Hip weakness was not a risk factor for patellofemoral pain (moderate evidence). Quadriceps weakness was a risk factor in military recruits (BMI-normalised SMD -0.69). Higher hip abduction strength was a risk factor in adolescents. Age, height, weight, BMI, body fat and Q angle were not risk factors. Incidence about 10%.
Moderate-to-strong prospective evidence that isometric hip strength is not associated with developing patellofemoral pain; moderate cross-sectional evidence that people with the condition have weaker hips; limited evidence that adolescents lack the deficit. Reduced hip strength may be a consequence rather than a cause.
Adding four lower-limb strengthening and four stretching exercises to supervised training over 14 weeks reduced anterior knee pain from 4.8% to 1.3% (unadjusted HR 0.25, 95% CI 0.13-0.52). Mixed programme, so the hip contribution can't be isolated; recruits, not runners.
Overall running injury incidence 40.2% (SD 18.8%). The knee, ankle and lower leg had the highest incidence; anterior compartment tendinopathy, patellofemoral pain and Achilles tendinopathy were the pathologies with the highest incidence. Methodological issues limit interpretation.