Rehabilitation following first-time patellar dislocation: a randomised controlled trial of purported vastus medialis obliquus muscle versus general quadriceps strengthening exercises.
BACKGROUND
We aimed to define whether distal vastus medialis (VM) muscle strengthening improves functional outcomes compared to general quadriceps muscle strengthening following first-time patellar dislocation (FTPD).


METHODS
Fifty patients post-FTPD were randomised to either a general quadriceps exercise or rehabilitation programme (n=25) or a specific-VM exercise and rehabilitation regime (n=25). The primary outcome was the Lysholm knee score, and secondary outcomes included the Tegner Level of Activity score, the Norwich Patellar Instability (NPI) score, and isometric knee extension strength at various knee flexion ranges of motion. Outcomes were assessed at baseline, six weeks, six months and 12months.


RESULTS
There were statistically significant differences in functional outcome and activity levels with the Lysholm knee score and Tegner Level of Activity score at 12months in the general quadriceps exercise group compared to the VM group (p=0.05; 95% confidence interval (CI): -14.0 to 0.0/p=0.04; 95% CI: -3.0 to 0.0). This did not reach a clinically important difference. There was no statistically significant difference between the groups for the NPI score and isometric strength at any follow-up interval. The trial experienced substantial participant attrition (52% at 12months).


CONCLUSIONS
Whilst there was a statistical difference in the Lysholm knee score and Tegner Level of Activity score between general quadriceps and VM exercise groups at 12months, this may not have necessarily been clinically important. This trial highlights that participant recruitment and retention are challenges which should be considered when designing future trials in this population.


LEVEL OF EVIDENCE
Therapeutic study, Level I.
['Smith|T O|TO|', 'Chester|R|R|', 'Cross|J|J|', 'Hunt|N|N|', 'Clark|A|A|', 'Donell|S T|ST|']
D005260:Female D005500:Follow-Up Studies D006801:Humans D007719:Knee Joint D065466:Lysholm Knee Score D008297:Male D053580:Muscle Strength D031222:Patellar Dislocation D052097:Quadriceps Muscle D016059:Range of Motion, Articular D055070:Resistance Training D012189:Retrospective Studies D013997:Time Factors D016896:Treatment Outcome D055815:Young Adult
Patellar dislocation Trial Quadriceps Exercise Vastus medialis oblique