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Address correspondence and reprint requests to: K.M. Crossley, School of Allied Health, College of Science, Health and Engineering La Trobe University, Bundoora, Victoria 3086, Australia. Tel: +61-3-9479-3902; Fax: +61-3-9479-5768.
Affiliations
Physiotherapy, School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, Queensland, AustraliaDepartment of Mechanical Engineering, The University of Melbourne, Parkville, Victoria, AustraliaSchool of Allied Health, College of Science, Health and Engineering La Trobe University, Bundoora, Victoria 3086, Australia
Centre for Health Exercise and Sports Medicine, Department of Physiotherapy, School of Health Sciences, The University of Melbourne, Parkville, Victoria, Australia
Patellofemoral joint osteoarthritis (PFJ OA) contributes considerably to knee OA symptoms. This study aimed to determine the efficacy of a PFJ-targeted exercise, education manual-therapy and taping program compared to OA education alone, in participants with PFJ OA.
Methods
A randomised, participant-blinded and assessor-blinded clinical trial was conducted in primary-care physiotherapy. 92 people aged ≥40 years with symptomatic and radiographic PFJ OA participated. Physiotherapists delivered the PFJ-targeted exercise, education, manual-therapy and taping program, or the OA-education (control condition) in eight sessions over 12 weeks.
Primary outcomes at 3-month (primary) and 9-month follow-up: (1) patient-perceived global rating of change (2) pain visual analogue scale (VAS) (100 mm); and (3) activities of daily living (ADL) subscale of the Knee injury and Osteoarthritis Outcome Score (KOOS).
Results
81 people (88%) completed the 3-month follow-up and data analysed on an intention-to-treat basis. Between-group baseline similarity for participant characteristics was observed. The exercise, education, manual-therapy and taping program resulted in more people reporting much improvement (20/44) than the OA-education group (5/48) (number needed to treat 3 (95% confidence interval (CI) 2 to 5)) and greater pain reduction (mean difference: −15.2 mm, 95% CI −27.0 to −3.4). No significant effects on ADL were observed (5.8; 95% CI −0.6 to 12.1). At 9 months there were no significant effects for self-report of improvement, pain (−10.5 mm, 95% CI −22.7 to 1.8) or ADL (3.0, 95% CI −3.7 to 9.7).
Conclusion
Exercise, education, manual-therapy and taping can be recommended to improve short-term patient rating of change and pain severity. However over 9-months, both options were equivalent.
, PFJ OA can adversely affect quality of life, economic productivity and daily function in younger adults with critical career and childcare responsibilities.
Clinical guidelines prioritise conservative (non-pharmacological) treatments as a first line knee OA management and recommend tailoring treatments to the location of joint damage
American College of Rheumatology 2012 recommendations for the use of nonpharmacologic and pharmacologic therapies in osteoarthritis of the hand, hip, and knee.
, supporting the recommendation for targeted interventions. Only two clinical trials specifically assessed treatments for PFJ OA, with no positive effects reported for either combined exercise therapy with patellar taping
Physiotherapy, including quadriceps exercises and patellar taping, for knee osteoarthritis with predominant patellofemoral involvement: randomized controlled trial.
Physiotherapy, including quadriceps exercises and patellar taping, for knee osteoarthritis with predominant patellofemoral involvement: randomized controlled trial.
Association of severity of coexisting patellofemoral disease with increased impairments and functional limitations in patients with knee osteoarthritis.
. This provides a rationale to consider treatments designed for PFJ pain in younger adults for older people with PFJ OA. Our previous clinical trials proved the effectiveness of quadriceps and hip muscle retraining exercises, patellar taping, and patellar mobilisation for PFJ pain in younger adults
We aimed to evaluate whether a PFJ-targeted program that combined (1) exercise, (2) education, (3) manual therapy and (4) taping, results in greater improvements in patient rated change, pain and physical function than physiotherapist-delivered OA education in participants with symptomatic and radiographic PFJ OA. We hypothesised that the PFJ-targeted program of exercise, education, manual-therapy and taping would be superior to the OA-education at 3 months, and that beneficial effects would not be present at 9-months.
Methods
Design overview
We conducted a randomised, assessor- and participant-blinded controlled clinical trial, as described previously
. The trial was prospectively registered in the Australian New Zealand Clinical Trials Registry (ACTRN12608000288325). The study had ethical approval (HREC number: 0721163) and all participants provided written informed consent prior to commencement, and all human testing procedures undertaken conformed to the standards of the Declaration of Helsinki.
Setting and participants
The clinical trial was conducted in primary care physiotherapy practices. Volunteers from the greater Melbourne (Australia) area responded to advertisements in print and radio media, posters in sporting clubs, health and medical practices and referrals from practitioners. Potential participants underwent telephone screening, followed by a physical screening by an experienced physiotherapist and standardised weight-bearing semi-flexed, standing, posteroanterior and skyline radiographs to assess the severity of TFJ and PFJ OA.
To be included, volunteers were required to be aged at least 40 years; have anterior or retro-patellar pain that was aggravated by two or more PFJ-loaded activities (e.g., stair ambulation, rising from sitting or squatting); have an average pain score of at least 3 on an 11-point scale (0 = no pain; 10 = worst pain possible) during aggravating activities and on most days during the past month; and have evidence of lateral PFJ osteophytes
. Participants were excluded if they had pain from other lower-limb sites; predominantly TFJ joint symptoms on clinical examination (e.g., location of pain, tenderness on palpation); current or previous (prior 12 months) physiotherapy for knee pain; recent knee injections (prior 3 months); previous or planned (following 6 months) knee surgery; physical inability to undertake testing; other medical conditions; inability to understand written and spoken English; and a body mass index (BMI) greater than 34 kg m−2. Additionally, individuals with medial >lateral PFJ osteophytes or moderate-to-severe concomitant TFJ OA (Kellgren and Lawrence
The randomisation sequence (computer-generated permuted blocks of 8–12) was generated a priori and kept external (University of Queensland) to the administration site (University of Melbourne) by an independent investigator. Participants were randomly allocated to either exercise, education, manual-therapy and taping or OA-education and were informed that two types of physiotherapist-delivered treatments were being compared, but the types of intervention and study hypotheses were concealed. A research assistant, not involved in outcome assessment, revealed the allocation to the physiotherapist delivering the intervention following baseline assessment and prior to the first appointment.
Each participant attended the private practice of one of eight trained project physiotherapists, at various Melbourne metropolitan sites. Physiotherapists were experienced in treating patients with knee and PFJ conditions and underwent 6 h of training (with KMC) to standardise the treatment elements and their prescription, as described in the published protocol
. Physiotherapists provided both the active and control interventions and thus were not blinded to group allocation. Eight treatments (approximately 60 min duration) were provided once a week for 4 weeks and then once every 2 weeks for 8 weeks for each group. The interventions have been described in detail previously
The PFJ-targeted exercise, education, manual-therapy and taping program was standardised to consist of (1) functional retraining exercises for the quadriceps and hip muscles; (2) quadriceps and hip muscle strengthening; (3) patellar taping; (4) manual-therapy (PFJ, TFJ and soft tissue mobilisation); and (5) OA-education (Supplementary Table). The standard elements of the treatment were then tailored, such that each participant's clinical presentation (e.g., strength, pain severity, swelling) as well as the presence of co-morbidities (e.g., back and hip pain or pathology) were taken into consideration, and exercises were chosen and progressed by the physiotherapist based on each participant's response to exercise load. This approach ensured that the highest level of load could be applied, whilst keeping the participant's pain to a minimal level (≤2 on a 0–11 numerical rating scale). Exercises were taught and supervised by the physiotherapist during each visit with a home exercise program prescribed, to be performed independently at home four times per week. An exercise manual was provided for participants with clear instructions and diagrams to ensure correct and safe performance of all exercises. At the completion of the 3-month intervention period and outcome assessment, participants were encouraged to continue with their home exercise program.
The OA-education intervention (control group) was a physiotherapist-delivered series of single-patient sessions, designed to control for the patient–therapist interaction and psychosocial contact inherent with the PFJ-specific physiotherapy intervention. The information was obtained from the Arthritis Victoria patient information sheets (http://www.arthritisvic.org.au), and at each session different topics were discussed (1): introduction to OA; (2): maintaining physical activity; (3): medicines; (4): complementary therapies; (5): healthy eating; (6) dealing with chronic pain; (7): emotions and depression and (8): summary, revision of key concepts.
Participants in both groups were encouraged to continue regular physical activity that did not provoke their pain. The use of adjunctive treatments (including prescription and over-the-counter medicines) were permitted and recorded in weekly log books.
Outcome measurements
A blinded examiner administered all outcome measures. In those with bilateral symptoms, the most symptomatic eligible knee was assessed. Participant characteristics were recorded at baseline. The principal time-point for efficacy analyses was at treatment completion (3 months), with a secondary follow-up time-point included after 6 months of no treatment to assess maintenance of effects (9 months).
Primary outcomes were patient-perceived global rating of change (from baseline) on a 5 point Likert scale (5 = much worse; 4 = worse; 3 = same; 2 = improved; 1 = much improved)
Validation study of WOMAC: a health status instrument for measuring clinically-important patient-relevant outcomes following total hip or knee arthroplasty in osteoarthritis.
, and a normalised score was calculated (100 represents no symptoms and 0 represents maximum symptoms). Secondary outcome measures included the pain, symptoms, sport and recreation and quality-of-life subscales of the KOOS. Adherence was measured from attendance at physiotherapy and completion of home exercise log books. Adverse events and medication use were recorded in log books. Participants were considered to be adherent with the home exercises if they completed three of the required four times per week (i.e., 75%).
Sample size
Based on our previous RCT of PFJ-targeted physiotherapy for PFJ pain
, we required 38 people per group to detect 49% of people in the physiotherapy group reporting much improvement on the global rating of change, compared with 19% of people in the education group, with 80% power (α = 0.05). A sample size of 90 also enabled detection of the minimal clinically important improvements of 19.9 (21.5) mm on a 100 mm pain VAS and 9.1 (13.9) normalised units on the WOMAC physical function subscale
, with 90% power (α = 0.05) and accounting for approximately 10% dropouts.
Statistical analysis
All analyses were performed with SPSS for Windows 21.0 software (SPSS, Chicago, IL, USA), conducted on an intention-to-treat basis. Global rating of change was dichotomised as no success (much worse, worse, same, moderate improvement) and success (marked improved), and expressed as relative risk reduction and Numbers Needed to Treat (NNT). Worst-case scenario imputation of missing values was performed, with targeted physiotherapy assigned much worse and OA-education assigned much improved. We analysed continuous outcome measures using linear mixed regression models, including their respective baseline scores as a covariate, participants as a random effect, treatment condition as a fixed factor and the covariate by treatment interaction. Analyses were repeated with participant characteristics (age, gender, BMI and radiographic disease severity) included as covariates to evaluate their impact. Regression diagnostics were used to check for normality of the measures and homogeneity of variance, where appropriate. Statistical significance was set at P = 0.05.
Results
Between August 2008 and December 2010, 365 people volunteered to participate in the study. In total, 92 people (Fig. 1) fulfilled the eligibility criteria and were randomised to the PFJ OA-targeted exercise, education, manual-therapy and taping protocol (n = 44) and OA-education control (n = 48) groups; 81 people completed the 3-month follow-up (39 physiotherapy and 42 OA-education; 88%) and 73 people completed the 9-month follow-up (35 physiotherapy and 38 OA-education; 79%). The two groups were similar at baseline for all participant characteristics (Table I). The characteristics of the 11 participants lost to follow-up were not different to those who completed the study.
Fig. 1CONSORT 2010 Flow Diagram (modified for individual randomized, controlled trials of non-pharmacologic treatment) Participants lost to follow-up at 3 months were not followed up at 9 months.
The exercise, education, manual-therapy and taping resulted in more people being much improved (20/44) than the OA-education group (5/48) at 3-months (relative risk 4.31; 95% confidence interval (CI): 1.79–10.36; NNT 3 (95% CI: 2–5) (Fig. 2)). The worse-case scenario imputation of missing values, with the exercise, education, manual-therapy and taping intervention assigned much worse and the OA-education assigned much improved, did not change the outcome substantially or statistically beyond 0.05. People in the combined exercise, education, manual-therapy and taping group reported significantly greater reductions in pain than those in the OA-education group (mean difference: −15.2 mm, 95% CI: −27.0 to −3.4). However, there were no significant effects on physical function as measured using the KOOS-ADL (5.8; −0.6–12.1). Including age, gender, BMI and radiographic disease severity as covariates did not affect the outcomes and hence, the unadjusted data are presented (Table II).
Fig. 2Percentage of participants reporting perceived improvement across categories from ‘much improved’ to ‘much worse’.
Table IIMean (SD) scores for continuous primary and secondary outcomes at baseline, 3 months and 9 months (adjusted for baseline scores), according to group
At 9-months, more people in the exercise, education, manual-therapy and taping group than in the OA-education group reported being much improved (relative risk 3.26 (95% CI 1.46–7.26); NNT 3 (95% CI 2–7)) (Fig. 2). However, imputing missing data (21%) on a worse-case scenario, the results were no longer statistically significant. No significant between-group differences were observed for participant-reported knee pain (10.5 mm; 95% CI −1.8–22.7), KOOS-ADL (3.0; 95% CI −3.7–9.7).
Secondary outcomes
At 3-months, the exercise, education, manual-therapy and taping intervention and the OA-education control resulted in similar outcomes for all secondary outcome measures (Table III) except for KOOS-pain, where those in the exercise, education, manual-therapy and taping group reported significantly greater reductions in KOOS-pain than those in the OA-education group (6.0; 95% CI 0.1–12.6). After 6-months of no treatment, there were no significant between-group differences (Table III).
Table IIIEstimated between-group differences, adjusted for the baseline value of the measure (mean difference and 95% CIs), in the change scores from baseline to 3 months and from baseline to 9 months
Baseline – 3 months
Baseline – 9 months
Primary outcomes
Knee pain on aggravating activity (0–100)
−15.2 (−27.0 to −3.4)*
−10.5 (−22.7 to 1.8)
KOOS-ADL (100–0)
5.5 (−0.6 to 11.2)
3.0 (−3.7 to 9.7)
Secondary outcomes
KOOS-Pain (100–0)
6.0 (0.1 to 12.6)*
1.4 (−5.2 to 8.0)
KOOS-Symptoms (100–0)
3.0 (−3.1 to 8.9)
−0.6 (−6.9 to 5.8)
KOOS-SR (100–0)
8.7 (−1.2 to 18.6)
6.2 (−4.2 to 16.5)
KOOS-QoL (100–0)
−0.1 (−7.1 to 7.0)
−0.9 (−8.3 to 6.5)
Knee pain on aggravating activities measured with a VAS (mm: 100 = maximal pain possible).
KOOS-ADL = ADL subscale of the KOOS (100 = best possible score).
KOOS-Pain = Pain subscale of the KOOS (100 = best possible score).
KOOS-Symptoms = Symptoms subscale of the KOOS (100 = best possible score).
KOOS-SR = Sport and recreation subscale of the KOOS (100 = best possible score).
KOOS-QoL = Quality of Life subscale of the KOOS (100 = best possible score).
No significant differences were observed between groups for attendance (mean (SD) number of sessions: Physiotherapy: 8 (2); OA-education 8 (1)). Log-books for exercise adherence were obtained from 31 (71%) of the participants in the physiotherapy group. Adherence with home exercises was recorded by 24 (77%) participants. Adverse events were noted in seven of the participants receiving the exercise, education, manual-therapy and taping intervention (skin reaction to tape wearing (n = 2)); swelling after treatment (n = 2); and pain in other areas after exercises (back n = 1; ankle n = 1; other knee n = 1). All adverse events were mild, did not require medical treatment, nor cause cessation of treatment (some adjustments to taping and/or exercises were made by the treating physiotherapist). Use of co-interventions, including medications, was similar between groups. In the group undertaking exercise, education, manual-therapy and taping, medication use was recorded in 10 people: analgesics (n = 7), non-steroidal anti-inflammatory drugs (n = 4) and glucosamine (n = 2). Similar medication use was recorded in the OA-education group: analgesics (n = 7), non-steroidal anti-inflammatory drugs (n = 4), glucosamine (n = 2) and fish oil (n = 1).
Discussion
Exercises, education, manual-therapy and taping, targeted to the PFJ resulted in superior outcomes for patient-perceived change in condition and pain, compared to physiotherapist-delivered OA-education. However physical function was not different between groups. There were no differences at 9-months.
Our study fills a gap in the literature, where most evidence exists for medial TFJ OA. The importance of our targeted intervention is underpinned by recent recommendations to tailor non-pharmacological management for knee OA
. Considering that approximately 70% of people aged above 50 with knee pain with or without radiographic OA have PFJ involvement, and the differences between the PFJ and TFJ compartment in joint biomechanics
Risk factors for magnetic resonance imaging-detected patellofemoral and tibiofemoral cartilage loss during a six-month period: the joints on glucosamine study.
Association of severity of coexisting patellofemoral disease with increased impairments and functional limitations in patients with knee osteoarthritis.
, a PFJ OA-focussed intervention is appropriate. Furthermore, people with PFJ OA derive lesser benefits than those with TFJ OA from a non-specific exercise therapy
that does not consider the unique functional and biomechanical impairments associated with PFJ OA. Our study shows that three patients with PFJ OA would need to be treated with our targeted physiotherapy intervention compared to OA-education, for one person to report a marked improvement in their condition.
Implications for management of PFJ osteoarthritis
Current management of PFJ OA remains problematic for most health and medical practitioners due to the lack of trials evaluating treatments tailored to this condition. Our treatment protocol addressed shortfalls of previous trials. We included information and education that addressed pacing of activity and discussion of weight management. Most importantly, the exercise program addressed the impairments commonly observed in PFJ OA (quadriceps and hip muscle weakness), tailoring the prescription and progression of exercises to individual abilities and co-morbidities. Patellar malalignment, a prominent feature of PFJ OA
, was assessed for each individual and addressed with patient-specific mobilisations and taping.
The lack of benefit following an additional 6 months of no treatment might indicate that interventions involving exercise, education, manual-therapy and taping for this patient population need to be extended. The targeted physiotherapy group was instructed to maintain their home exercise programme. However, the programme was not supervised or progressed over the following 6 months. Furthermore, adherence to the unsupervised programme is unknown. Considering that OA is a chronic disease, our results indicate the need for trials with either an extended supervised treatment duration, or additional means to ensure adherence to an unsupervised programme.
This study has a number of important strengths. To facilitate recruitment of those with predominant PFJ OA, our eligibility criteria included history, examination and radiographic criteria. The studied treatment was evidence-based and incorporated recommendations from clinical guidelines. Our comparison group (physiotherapist-delivered OA-education) controlled for the patient–therapist interaction inherent within our targeted physiotherapy intervention and sought to reduce performance bias. Participants and assessors were blinded to treatment allocation, to reduce the treatment bias and/or response bias. Adherence to the interventions was high and adverse events were mild.
There are some limitations to our study, with the main one being a loss of 21% of participants to follow up at 9-months. The worse-case scenario imputation for missing data implemented in the analysis lead to a conclusion of no benefit of exercise, education, manual-therapy and taping over OA education alone. The impact on the interpretation of the long-term outcomes might undermine the potentially real benefits of the exercise, education, manual-therapy and taping, because analysis without worse case scenario imputation showed a beneficial effect of the education, exercise, manual-therapy and taping program. While there was a 12% loss of participants to follow up on the primary outcome at 3 months, the effect of the exercise, education, manual-therapy and taping program was still present on imputing missing data on a worst-case scenario basis. As with other non-pharmacological trials, it is not possible to blind the physiotherapists providing the treatment. Furthermore, the results of this trial cannot be extrapolated to those with different clinical features or patterns of radiographic OA, and the long-term effects cannot be assumed and should be evaluated.
In conclusion, after 3-months an 8-session multi-modal treatment of exercise, OA education, manual-therapy and taping that was targeted to the PFJ and tailored to individual patients resulted in superior outcomes for patient-perceived change and pain compared to OA-education alone in people with predominant PFJ OA. However, there was no significant difference in physical function and the positive effects observed after 3 months of treatment were not maintained after 6 months of no treatment. Conservative management of PFJ OA may be enhanced by targeting interventions to the PFJ compartment.
Author's contributions
KMC, RSH, BV, MGP, and AGS conceived the project and KMC co-ordinated the trial. KMC, RSH, BV, MGP, and AGS developed the protocol and procured the project funding. KMC, RSH and BV designed the physiotherapy and control treatments and KMC trained the physiotherapists. BV performed the sample size calculations and designed the statistical analyses. JL and HO recruited and screened participants. BV randomised participants to groups. All authors provided feedback on drafts of this paper and read and approved the final manuscript.
Role of the funding source
The funding body (Australian National Health & Medical Research Council) had no role in the study design or data analyses.
Competing interests
The authors declare that they have no competing interests.
Acknowledgements
This trial was funded by the National Health and Medical Research Council (NHMRC, Project #508966). RSH (FT#130100175) is funded in part by Australian Research Council Future Fellowship. The physiotherapists who delivered the physiotherapy and control treatments were Ann Ryan, Cameron Bicknell, Steve Hawkins, Cate Boyd, Daniel Zwolak, Sharbil Wehbe, Peter Thomas, and George Tsai. We wish to thank the patients for participating in the project.
Appendix A. Supplementary data
The following is the supplementary data related to this article:
American College of Rheumatology 2012 recommendations for the use of nonpharmacologic and pharmacologic therapies in osteoarthritis of the hand, hip, and knee.
Physiotherapy, including quadriceps exercises and patellar taping, for knee osteoarthritis with predominant patellofemoral involvement: randomized controlled trial.
Association of severity of coexisting patellofemoral disease with increased impairments and functional limitations in patients with knee osteoarthritis.
Validation study of WOMAC: a health status instrument for measuring clinically-important patient-relevant outcomes following total hip or knee arthroplasty in osteoarthritis.
Risk factors for magnetic resonance imaging-detected patellofemoral and tibiofemoral cartilage loss during a six-month period: the joints on glucosamine study.
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