Background There are no accepted objective criteria for return to activity after a first time lateral patella dislocation.

Objective To define the characteristics of first time lateral patallofemoral dislocation (PFD) patients and their timeline for return to activity.

Design Prospective observational.

Setting University and private clinic.

Patients 31 patients were identified between Sept 2008 and 2010; confirmed by MRI (87%) or requiring reduction maneouver (13%). 23 agreed to non-operative treatment and structured physical therapy. Activity level was recorded.

Intervention The independent variable was redislocation.

Results There were 15 males and 16 females. Average age was 20. The majority of injuries occurred playing sports and were non-contact (70%).

The 23 patients all returned to full activity with no time off to nine months. 12 had no re-dislocations at 1 year. One re-dislocation occurred in a 15 year old male at 18 months. 10 patients had formal clearance for a full return to activity. Seven patients completed physical therapy.

KOOS data demonstrated minimal change between time of injury and month 3, and no change between 6 and 12 months.

Conclusion All patients were on a structured physical therapy program with clearly defined functional parameters for return to activity. Most patients choose not to complete therapy and used self defined parameters for return to activities. Follow up indicates that most returned to previous level of function without known adverse sequelae.

This high rate of non-compliance with physical therapy and lack of physician clearance prior to return to activity is disconcerting. There is a disparity between the clinician's and patient's perceived seriousness and need for time off and rehabilitation.

KOOS outcome tool may not be capturing the disability associated with lateral PFD.

More attention is warranted to optimise management of this injury, to better understand the degree of impairment and timing of safe return.