Patellar Dislocations: Treatment

Cryotherapy and Elevation: Ice,rest, and elevation above the heart are effective interventions to reduce pain and inflammation following an acute dislocation. Reduction of swelling will help the quadriceps return to function as quickly as possible.

image[55]    image[54]image[53]

Left: McConnell Taping    Center: lateral patella     Right: Centered patella during taping

Taping: McConnell taping may be an effective intervention in preventing dislocations and reducing pain post dislocation, as it may reduce lateral tracking of the patella and has been shown to increase VMO activation. Furthermore, as shown above McConnell taping also helps in patello-femoral pain by distributing forces through the entire trochlea, as opposed to a localized force to the patella when the patella tracks laterally. Basic physics tells us that the redistribution of force will assist in symptom relief. Be sure to pull the tape medially and wrap to the posterior side of the knee for maximal effect, in my experience

Recently, the Medial Patellar Femoral Ligament (MPFL) has been thought to be a primary pain producer with abnormal tracking of the patella. The MPFL is normally torn in a patellar dislocation, which will usually result in scarring that assists in reconnecting the patella to the femur.

Hip strengthening: The primary physical therapy intervention for the prevention of a patellar dislocation is hip external rotator strengthening. Reducing eccentric femoral internal rotation will keep the patella from tracking laterally (see previous post on etiology of dislocations). Reduction of laterally tracking will help pain, as an overstretch phenomenon to the MPFL (a primary pain producer in the knee) will occur with lateral tracking.

Medial Arch Supports: This would be similar in concept to the hip strength in that you want to decrease the tibial external rotation that accompanies femoral internal rotation, in order to decrease the lateral pull on the patella during activities. An orthotic with medial arch support would reduce pronation and therefore reduce the strain of the patella and the MPFL.

Core Strength & VMO strength: Core strength, specifically of the lower abdominals (transverse abdominus, external obliques) provides a stable base that not only allows for stronger lower extremity performance, but specifically has been shown to decrease femoral internal rotation.

VMO strength is a classic treatment in patellar instability from MDs, and although VMO activation may help reduce lateral tracking the efficacy of exercises to target the VMO is questionable. The quadriceps muscles (including the VMO) are all innervated together, therefore general quadriceps strengthening should help VMO strength.

Another point that should be mentioned is research done by Senavongse et al showed that simulated muscle tension has little effect on patellar mobility, which indicates that the MPFL, not the VMO is the primary restraint to lateral patellar tracking.

mpfl

Operative Treatment:

In the case of chronic dislocators, surgical intervention may be necessary. The recent research are trending away from a release of the lateral retinaculum and towards MPFL reconstruction and possibly a tibial tubercle transfer to reduce the Q angle (shown below).

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In regards to surgical intervention after a single dislocation, it’s been reported that the results are equivocal, with 67% re-dislocation rate in the operative group, and 71% in the non-operative group.

Surgical Reconstruction should be considered in the presence of patellar instability due to excessive laxity of the MPFL. This can be seen on physical examination, in an MRI, or in an arthrotomy. Surgical intervention should not be used for pain in isolation. Although surgery does result in significant increases in function in episodic dislocators, it should be noted that rehabilitation for an MPFL Reconstruction is a long and potentially painful process that can leave patients with significant quadriceps weakness. Potential surgical candidates should get all the facts before going ahead with surgery.

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