Quadriceps or hip exercises for patellofemoral pain? A randomised controlled equivalence trial

Key Points

1. Exercise therapy has been shown to be beneficial in the treatment of patellofemoral pain in the short and medium term.
2. Hip strengthening and quadriceps strengthening exercises have shown similar improvements in anterior knee pain intensity and patient-function in the short term.
3. The short-term pain and functional improvements were also sustained at 26 weeks since initiation of both exercise protocols.

BACKGROUND & OBJECTIVE

The 2018 Consensus statement on exercise therapy and physical interventions for treating patellofemoral pain identified several areas of uncertainty (1). These included the preference for hip exercises over knee exercises, the efficacy of combined interventions for adolescents with patellofemoral pain, the effectiveness of patellar taping and bracing, and the potential benefits of adjunctive treatments like acupuncture and manual soft tissue therapy (1).

While exercise therapy is known to be the preferred treatment for improving pain and function in individuals with patellofemoral pain in the short and medium term, this study aimed to compare the effectiveness of a quadriceps exercise (QE) protocol versus a hip exercise (HE) protocol on symptoms and function in these patients.

The 2018 Consensus statement on exercise therapy and physical interventions for treating patellofemoral pain identified several areas of uncertainty.

Exercise therapy focusing on hip and quadriceps muscle groups can also be combined with other treatment interventions such as orthotics, taping, or bracing.

METHODS

• The study adhered to CONSORT guidelines for non-pharmacological treatments and utilized the TIDieR checklist for intervention description. Assessments were conducted at baseline and 12 weeks, with additional online patient-reported outcomes at 26 weeks.

• Eligible participants had a clinical diagnosis of patellofemoral pain (PFP) in one knee, verified by a sports medicine physician without imaging.

• They also reported an average knee pain intensity of ≥ 3/10 during daily activities, symptom onset without trauma, persistent pain for at least four weeks, and knee pain associated with at least three of the following actions: activity, prolonged sitting, stair climbing or descending, or squatting. Exclusion criteria included other knee pathologies, recurrent patellar subluxation or dislocation, and previous knee surgery.

• Participants were randomly assigned to either the QE or HE group.

• Physiotherapists and participants were not blinded to treatment allocation, but investigators and outcome assessors were blinded. The interventions lasted 12 weeks with three home exercise sessions (8 -12 repetitions x 3 sets, each exercise) per week.

• The HE program included specific exercises (clam shell, side-lying/ standing hip abduction and prone/standing hip extension using elastic bands, while the QE program included different exercises (seated knee extension, squat and forward lunges) using elastic bands or ankle weights or dumbbells (see video).

QUADRICEPS-FOCUSED AND HIP-FOCUSED EXERCISE PROGRAMMES FOR PATELLOFEMORAL PAIN

• Adherence was monitored with an exercise diary, and satisfactory adherence was defined as completing at least 24 out of 36 scheduled training sessions.

• Primary outcome for the study was the change from baseline in the anterior knee pain scale (AKPS) at week 12 and 26 (minimally clinical important change was considered as 8 to 10 points). Secondary outcomes were changes in KOOS pain score, KOOS function score, KOOS quality of life score at week 12 and 26.

RESULTS

• 200 out of 288 participants were included in the study after screening for eligibility, predominantly women (69%). 100 participants each were grouped in QE and HE groups, respectively. The participants had a mean age of 27.2 years and mean BMI of 22.6. Participants completed 28/36 exercise sessions.

• Mean change in the AKPS score (primary outcome) was 7.6 in the QE group and 7.0 in the HE group from baseline to week 12. The estimated treatment differences in the secondary outcomes were 2.9 for KOOS pain score, 1.0 for KOOS function, and - 1.2 for KOOS quality of life score.

• The results in the primary and secondary outcomes remain unchanged at week 26. Some participants experienced adverse events like muscle soreness, knee pain exacerbation, headache, and back pain. The study also reported 10% to 11% increase in hip abduction and knee extension muscle strength after 12 weeks in both exercise groups.

LIMITATIONS

The limitations of this study include home-based exercise programs with limited supervision, potentially leading to incorrect performance. The self-reported exercise adherence data may be overestimated due to social desirability and recall bias. The study was conducted at a single center, limiting external validity. Contamination of the interventions may have occurred due to unsupervised exercises.

CLINICAL IMPLICATIONS

The 2019 clinical practice guidelines for patellofemoral pain (PFP) recognized four sub-categories of impairments in patients with PFP. These categories were based on impairments presented in PFP patients which were due to overload or overuse, muscle performance deficits, movement co-ordination deficits, and mobility impairments (2). They recognized that the group of patients who present with muscle performance deficits, observed mostly in the hip and quadriceps muscle respond well to hip and knee strengthening exercises (2). The findings of this study are most applicable to this sub-group of patients.

This study informs clinicians about similar treatment effects with the application of either exercise protocols, therefore, clinicians can rely on their ability to recognize unique risk factors for each patient and individualize interventions accordingly. Exercise therapy focusing on hip and quadriceps muscle groups can also be combined with other treatment interventions such as orthotics, taping, or bracing; as no single intervention has shown to be effective in isolation for patients with PFP (3).

Prevalence of PFP has been recorded to be highest in two ranges of age groups i.e. 12 years to 19 years and 50 to 59 years (2). However, the findings of this study may not be directly applicable to these age groups as age range in this study population was from early 20s to early 30s.

+STUDY REFERENCE

Hansen R, Brushøj C, Rathleff M, Magnusson S, Henriksen M (2023) Quadriceps or hip exercises for patellofemoral pain? A randomised controlled equivalence trial. Br J Sports Med, 57(20), 1287-1294.

SUPPORTING REFERENCE

1. Collins NJ, Barton CJ, van Middelkoop M, Callaghan MJ, Rathleff MS, Vicenzino BT, Davis IS, Powers CM, Macri EM, Hart HF, de Oliveira Silva D, Crossley KM. 2018 Consensus statement on exercise therapy and physical interventions (orthoses, taping and manual therapy) to treat patellofemoral pain: recommendations from the 5th International Patellofemoral Pain Research Retreat, Gold Coast, Australia, 2017. Br J Sports Med. 2018 Sep;52(18):1170-1178.
2. Willy RW, Hoglund LT, Barton CJ, Bolga LA, Scalzitti DA, Logerstedt DS, et al. Patellofemoral pain: clinical practice guidelines linked to the international classification of functioning, disability and health from the Academy of Orthopaedic Physical Therapy of the American Physical Therapy Association. J Orthop Sports Phys. 2019; 49:CPG1–CPG95.
3. Sisk D, Fredericson M. Update of Risk Factors, Diagnosis, and Management of Patellofemoral Pain. Curr Rev Musculoskelet Med. 2019 Dec;12(4):534-541.