Primary Patellar Dislocation: Management

Patellar dislocation accounts for 2 – 3% of all knee injuries, however, is the second most common cause of knee haemarthrosis (Aglietti et al., 2001). Patellar dislocation is most commonly associated with sports injuries, and therefore, is encountered commonly by the sports physiotherapist. In recent times there has been controversy on the most appropriate forms of management following primary (or first time) patellar dislocation.

Management-

A CASE FOR PRIMARY SURGERY:-

Stefancin and Parker (2007), suggest that surgery is indicated in the following cases:
*.Significant chondral injury
*.Osteochondral fractures
*.Large medial patellar stabilizer defects (i.e. MPFL, medial retinaculum, VMO)
*.Subsequent dislocation
*.Failure to improve with conservative management

CONSERVATIVE MANAGEMENT:-

The physiotherapy management of patellar dislocation should include the following:

A period immobilisation/bracing in extension (at least 3 weeks). This follows the results of Maenpaa and Lehto (1997) who found a 3-fold higher risk of redislocation in those treated with immediate mobilization, rather than a period of immobilisation.This should be followed by functional rehabilitation, with the aims of:
*.Quadriceps strengthening
*.VMO Biofeedback – aimed at reducing inhibition*.Restoration of ROM
*.Stretching of lateral structure tightness
*.Mobilisation for cartilage nutrition

The outcomes of conservative management are quite favourable. The systematic review (Stefancin and Parker, 2007) showed an excellent to good results in 76% of patients, with an average re-dislocation rate of about 48%.

ASPIRATION:-

In patients who present with significant effusion, aspiration may aid both therapy and diagnosis (Stefancin and Parker, 2007). This is because:
*.It can decrease pain and local anaesthetic injection can improve both clinical and radiographic assessment
*.It will achieve joint depression
*.Larger haemarthrosis volume will be related to a larger injury to the medial patellar stabilizers and/oran osteochondral injury
*.Analysis of the aspirate may identify the presence of fatty globules, which is indicative of an osteochondral fracture.

SURGICAL MANAGEMENT:-

As stated above, there are a number of cases in which surgical management is indicated. If the osteochondral fracture is greater than 10% of the patella articular surface, or if it is a part of the weight-bearing portion of the lateral femoral condyle, open repair is indicated (given that the fragment is amendable to fixation). Any large defects in the medial patellar stabilisers should under repair/reconstruction. A lateral release can also be performed to release tight lateral structures.The results of surgical management are positive. Subjectively there has been excellent to good results in 69% of patients, with a lower re-dislocation rate of 12%.