Knee arthroscopy and exercise versus exercise only for chronic patellofemoral pain syndrome: 5-year follow-up
- Jyrki A Kettunen1,2,
- Arsi Harilainen2,
- Jerker Sandelin2,
- Dietrich Schlenzka2,
- Kalevi Hietaniemi3,
- Seppo Seitsalo2,
- Antti Malmivaara4,
- Urho M Kujala5
- 1Arcada University of Applied Sciences, Jan-Magnus Janssonin aukio 1, Helsinki, Finland
- 2The ORTON Orthopaedic Hospital, ORTON Foundation, Helsinki, Finland
- 3The Helsinki University Central Hospital, Jorvi Hospital, Espoo, Finland
- 4Centre for Health and Social Economics, CHESS, National Institute for Health and Welfare, Helsinki, Finland
- 5The Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland
- Correspondence toDr Jyrki A Kettunen, Arcada University of Applied Sciences, Jan-Magnus Janssonin aukio 1, FIN-00550 Helsinki, Finland;
- Accepted 5 January 2011
- Published Online First 25 February 2011
Objective To study the long-term outcome of arthroscopy in patients with chronic patellofemoral pain syndrome (PFPS), the authors conducted a randomised controlled trial. The authors also investigated factors predicting the outcome in patients with PFPS.
Methods Fifty-six patients with PFPS were randomised into two groups: an arthroscopy group (N=28), treated with knee arthroscopy and an 8-week home exercise programme, and a control group (N=28), treated with a similar 8-week home exercise programme only. The primary outcome was the Kujala score on pain and function at 5-year. Secondary outcomes were visual analogue scales (VASs) to assess activity-related symptoms.
Results According to the Kujala score, both groups showed a marked improvement during the 5-year follow-up: a mean improvement of 14.7 (95% CI 9.9 to 19.4) in the arthroscopy group and 13.5 (95% CI 8.1 to 18.8) in the controls. No differences between the groups in mean improvement in the Kujala score (group difference 1.2 (95% CI –8.4 to 6.1)) or in the VAS scores were found. None of the investigated factors predicted the long-term outcome, but in most of the cases the treatment result immediately after the exercise programme remained similar also after the 5-year follow-up.
Conclusion Our RCT, being the first of its kind, indicates that the 5-year outcome in most of the patients with chronic PFPS treated with knee arthroscopy and home exercise programme or with the home exercise programme only is equally good in both groups. Some of the patients in both groups do have long-term symptoms.
Trial registration Current Controlled Trials ISRCTN 41800323.
Patellofemoral pain syndrome (PFPS) is a common problem, especially among physically active adolescents and young adults. The possibly multifactorial aetiology of PFPS is still partly unknown, and many conservative and surgical procedures have been used to treat patients with the syndrome.1
There is some evidence that exercise therapy reduces anterior knee pain in patients with PFPS.2 Although there is general consensus that the initial treatment should be conservative, in chronic cases and after failure of conservative treatment, arthroscopy is often carried out. Some randomised controlled trials (RCTs) have compared the effects of various operative techniques,3 4 but to our knowledge our previously published study5 was the first RCT which compared surgical interventions with conservative therapy in the treatment of PFPS. We found that both groups, the first treated with knee arthroscopy and a home exercise programme, and the second treated with the home exercise programme only showed equally marked improvement during the 9-month and 24-month follow-ups. The aim of the present study was to investigate the 5-year results of these patients. We also investigated factors possibly predicting the long-term outcome in patients with chronic PFPS.
The study methods and short-term follow-up results have been previously published.5 Briefly, orthopaedic surgeons identified female or male PFPS patients between May 2003 and February 2005 in the Helsinki area. These patients participated in a clinical examination at the ORTON Orthopaedic Hospital in Helsinki and answered a structured questionnaire. All 56 patients who fulfilled the inclusion criteria signed an informed consent. The trial profile is presented in figure 1.
Randomisation process and treatment groups
The patients were randomised into two treatment groups: an arthroscopy group, which was treated with knee arthroscopy and 8-week home exercise programme, and a control group, which was treated with the same 8-week home exercise programme only.
The 8-week home exercise programme was started 3 weeks after randomisation in all patients. Patients visited a physiotherapist twice, and the patients were given instructions on lower-limb muscle strengthening and stretching exercises to be performed daily at home. The duration of each daily home exercise session was approximately 30 min. Patients were told to avoid symptom-producing activities during the intervention.5
All the patients who were randomised into the arthroscopy group received arthroscopy. All the knee compartments were examined systematically, and pathological findings were recorded. The stage of cartilage lesions in the patellofemoral joint was recorded on a standard form according to the Outerbridge classification.6 During arthroscopy, the treatment procedures were performed, if justified on the basis of the arthroscopic findings and according to our predetermined, generally accepted recommendations.5 7
The 5-year follow-up outcome measures were collected using self-administered postal questionnaires. The primary outcome measure was the Kujala score,8 which is considered to be reliable, valid and responsive outcome measure for PFPS.9 According to Crossley et al,9 a clinically significant improvement is 8–10 points.
As secondary outcome measures, we used visual analogue scales (VASs) to assess activity-related pain during the previous 2 days when ascending stairs, descending stairs and standing up from a sitting position. Also, a global rating of the change between the baseline and follow-up (overall assessment) was evaluated with an additional six-point scale: 1=asymptomatic knee to 6=marked worsening. The scale was later on modified to: (1) marked worsening, moderate worsening or no change from baseline versus (2) moderate improvement, marked improvement or asymptomatic knee.
The baseline characteristics age, gender, body mass index (BMI), duration of knee symptoms, presence of bilateral symptoms and volume of leisure-time physical activity were analysed for their prognostic value. We also dichotomised the Kujala score to evaluate the relationship between the treatment result immediately after the 8-week home exercise programme and the result after the 5-year follow-up. For that purpose, the Kujala score was dichotomised and analysed as follows: 0=not improved (at most 9 points' improvement) and 1=improved (at least 10 points' improvement).
The statistical analysis was carried out with Statistical Package for the Social Sciences 17.0. The primary analysis was intention-to-treat, and the primary follow-up time was 5 years from randomisation. Comparisons between the groups were performed with analysis of covariance using the baseline scores as a covariate. The secondary follow-up period was from 24 months to 5 years from randomisation. The possible prognostic factors were analysed using univariate regression analyses.
Fifty-six patients underwent randomisation, and at the 5-year follow-up, 24 (86%) patients in the arthroscopy group and 20 (71%) in the control group responded to the questionnaire (figure 1). The mean follow-up time in the arthroscopy group was 5.2 years, and the corresponding time in the control group was 5.3 years (p=0.293). Three patients in the control group insisted on having an arthroscopy carried out after the exercise intervention. These patients participated in the follow-up, and they were analysed according to their original group assignment based on to the intention-to-treat principle. The mean change in the Kujala score in these three patients was 5.3, while among the remaining patients in the control group, the mean improvement was 13.6. The baseline characteristics were similar between the groups (table 1).
The mean improvement in the Kujala score between randomisation and follow-up was 15.6 (95% CI 11.1 to 20.1, p<0.001)) in the arthroscopy group and 12.3 (95% CI 5.1 to 19.9, p=0.002) in the control group. No baseline-adjusted difference between the two groups was observed in mean improvement according to the Kujala score or VAS scores (table 2). While the 5-year Kujala score was missing for some patients, the available data from the nearest time point (ie, shorter follow-up) were used, and based on this additional intention-to-treat analysis, there was no group difference in Kujala score improvement (mean group difference 3.3, 95% CI −3.2 to 9.8, p=0.310).
In the arthroscopy group, 79%, and in the control group, 74% of the patients reported at least a moderate improvement at the end of the follow-up period (p=0.47). When the arthroscopy and control groups were combined, the mean change in Kujala score among those patients who reported no improvement during the 5-year follow-up was 6.7 (SD 6.3), and among those with at least moderate improvement it was 16.4 (SD 13.2) (p=0.003).
Arthroscopy findings and outcome
The Kujala score improved between randomisation and 5-year follow-up in the arthroscopy group in those without a cartilage lesion by 17.8 points and in those with a cartilage lesion by 14.9 points (p=0.330 for the difference). Four of the five patients with a normal finding in arthroscopy answered to the 5-year questionnaire, and the mean improvement in these patients was 18.8 points. The Kujala score improved by 14.8 points among the 16 patients who had at least one abnormality, and who had surgical procedures owing to their abnormalities, and by 18.5 points among those who had some abnormalities documented at arthroscopy, but did not have any surgical procedure (N=4).
None of the baseline characteristics was associated with the 5-year treatment result. However, when the both groups were combined in 81% of the patients who had improved at least 10 points in the Kujala score immediately after the 8-week home exercise programme, the result had remained also after the 5-year follow-up. Furthermore, 77% of the patients who had not improved (<10 points in Kujala score) immediately after the exercise programme had poor treatment results also after the 5-year follow-up.
As seen in our shorter follow-up5 the present study confirmed that arthroscopy did not provide any additional advantage in the long term for chronic PFPS patients when carried out in addition to the training programme. None of the investigated baseline characteristics predicted the long-term outcome, but the treatment results immediately after the 8-week exercise programme remained also at the 5-year follow-up in most of the cases.
It is noteworthy that in 81% of the subjects who reported a clinically significant improvement after the 8-week exercise programme by at least 10 points in the Kujala score, the treatment result had remained for over 5 years. Because we did not have a group with no treatment in our study, we could not control the natural course of the PFPS. However, only patients with chronic symptoms were included in our study, and it would have been difficult and perhaps unethical to leave some of the patients without any treatment. Our results confirm earlier findings of exercise therapy reducing knee pain in patients with PFPS.2 10
Some of our patients had not improved after the 8-week exercise programme, and the poor treatment results had remained in three of the four during the 5-year follow-up. This finding supports the earlier view that some patients have long-term PFPS symptoms.11 While PFPS is common especially in physically active people, one explanation for the recovery may have been that the patients have reduced their physical activity. Therefore, we computed the volume of physical activity at the baseline and at the 5-year follow-up using a previously validated method12 (data not shown). On average, the patients who reported to have improved according to Kujala score at 5 years continued their physical activities at the same level as at the baseline. In contrast, those patients who had not improved had reduced the volume of physical activity.
What is already known on this topic
▶ Patellofemoral pain syndrome (PFPS) is a common problem, especially among physically active adolescents and young adults.
▶ The initial treatment of PFPS is conservative, but in chronic cases and after failure of conservative treatment, arthroscopy is often carried out.
▶ No randomised controlled trials (RCTs) have previously assessed the long-term effect of arthroscopy for PFPS.
What this study adds
This RCT indicates that treatment of patients with chronic PFPS with knee arthroscopy and a home exercise programme compared with treatment with a home exercise programme only results in a similar overall improvement in 5-year follow-up. Arthroscopy with generally recommended finding-specific surgical procedures does not provide any additional advantages for these patients.
In the arthroscopy group, all knee compartments were systematically evaluated, and possible knee pathologies were treated following generally accepted recommendations. Our primary aim was to study the efficacy of arthroscopy in patients with chronic PFPS, and the number of patients with various arthroscopy findings did not allow us to investigate in detail the association between different arthroscopy findings and long-term outcome. However, in the arthroscopy group, the improvement in Kujala score was especially high both in patients with normal findings and in those with abnormalities but did not have any surgical procedure.
Competitive athletes, and also patients younger than 18 and those over 40 years of age were excluded from this study. Therefore, our results are valid for young adults who do not participate in competitive sports. A simple 8-week home exercise programme instructed by a PT, and advice to avoid symptom-producing activities during the intervention may reduce symptoms in patients with chronic PFPS.
In conclusion, our 5-year follow-up of a randomised trial indicates that chronic patients with PFPS treated with a knee arthroscopy and home exercise programme or home exercise programme only show a similar overall improvement. Arthroscopy does not provide any additional advantages for these patients. Despite adequate treatment, some of the patients continue to have symptoms.
The authors wish to thank the personnel at the ORTON Orthopaedic Hospital and at the hospitals of the Hospital District of Helsinki and Uusimaa for their contributions to the study.
Funding Supported by a grant from The Social Insurance Institution of Finland.
Competing interests None.
Ethical approval Ethics approval was provided by the Hospital District of Helsinki and Uusimaa and the review board of the ORTON Orthopaedic Hospital.
Provenance and peer review Not commissioned; externally peer reviewed.