Cochrane: Patellofemoral
pain syndrome (PFPS) is a common knee problem, which particularly
affects adolescents and young adults. PFPS is characterised by
retropatellar (behind the kneecap) or peripatellar (around the kneecap)
pain. It is often referred to as anterior knee pain. The pain mostly
occurs when load is put on the muscles that extend the leg when climbing
stairs, squatting, running, cycling or sitting with bent knees.
Exercise therapy is often prescribed for this condition.
Results of the search and description of studies
We searched the medical literature until May 2014 and found 31
relevant studies involving 1690 participants with patellofemoral pain.
The studies varied a lot in the characteristics of their study
populations (e.g. activity levels and duration of their symptoms) and
type of exercises. We assessed most trials as being at high risk of bias because the people, often the trial participants, who assessed outcome knew what treatment group they were in.
The included studies, some of which contributed to more than one
comparison, provided evidence for the following comparisons: exercise therapy versus control (10 trials); exercise therapy
versus other conservative interventions (e.g. applying adhesive tape
over the knee; eight trials evaluating different interventions); and
different exercises or exercise programmes. The latter group comprised:
supervised versus home exercises (two trials); foot fixed (closed
kinetic chain) versus foot free (open kinetic chain) exercises (four
trials); variants of closed kinetic chain exercises (two trials making
different comparisons; other comparisons of other types of kinetic chain
or miscellaneous exercises (five trials evaluating different
interventions); hip and knee versus knee exercises (seven trials); hip
versus knee exercises (two studies); and high- versus low-intensity
exercises (one study). There were no trials testing the exercise medium (land versus water) or duration of exercises.
Quality of the evidence
The evidence, where available, for each of seven main outcomes for
all comparisons was of very low quality. This means that we are very
unsure about the reliability of these results.
Results of the two largest comparisons
The evidence for the comparison of exercise therapy versus control (e.g. no treatment) showed that exercise therapy
may provide a clinically important reduction in pain during activity
and usual pain in the short term (three months or less) and in the long
term (more than three months). The review also found evidence that exercise therapy
may provide a clinically important improvement in functional ability in
both the short and long term, as well as resulting in greater numbers
reporting recovery from their symptoms in the long term.
The review
found evidence that hip plus knee exercises may provide a clinically
important reduction in pain during activity and usual pain in the short
term and pain during activity in the long term, when compared with knee
exercises only. There was inconclusive evidence to say whether
functional ability or recovery was better in either group.
Conclusions
This review has found very low quality but consistent evidence that exercise therapy
for PFPS may result in clinically important reduction in pain and
improvement in functional ability, as well as enhancing long-term
recovery. However, we cannot say what is the best form of exercise therapy
nor whether this result would apply to all people with patellofemoral
pain. There is some very low quality evidence that hip plus knee
exercises may be more effective in reducing pain than knee exercise
alone.
Before further studies are done, research is needed to identify priority questions and achieve better consensus on diagnostic criteria and measurement of outcome.