Patella Instability: When Should Surgery Be Considered?
by Seth Sherman, MD
Patella dislocation is the second most common cause of traumatic knee injury behind an anterior cruciate ligament (ACL) tear. The patella or “kneecap” may dislocate (i.e., pop out of place) during sports participation. This may be the result of a contact/collision or a non-contact injury while cutting or pivoting. Sometimes, the patella comes partially out of its groove, termed a subluxation. Other times, the patella fully dislocates and either goes
back into place spontaneously or it may require a physician on the field or in the emergency room putting it back in place. The initial treatment of patella instability is to follow the RICE protocol (Rest, Ice, Compression, Elevation) and to consider a brief period of crutches, bracing, and anti-inflammatory medication. The decision to operate following a patella instability event is often complex. Below are some pearls to help you determine when a consultation with a surgeon may be recommended.

First of all, the vast majority of visits to the doctor for patellofemoral issues are for pain and NOT for instability
(i.e., dislocation, subluxation). There is no role for surgical stabilization for patellofemoral pain syndrome. Rehabilitation is the recommended treatment. For patients with a subluxation event or even multiple minor events, a trial of non-surgical treatment is also highly recommended. This should include a comprehensive “core to floor” rehabilitation plan. Temporary use of a patella stabilization brace or sleeve may be helpful. Activity modification is followed by clearance for return to sport once range of motion, strength, and functional movements are optimized to help prevent recurrent injury. Surgical stabilization is only considered after failure of conservative treatment.

The majority of first time patella dislocation events may also be treated non-surgically, with the recurrent dislocation rate ranging from 17–44%. In patients with otherwise normal bone alignment, higher energy is required for dislocation (i.e., football collision). These patients may present with large knee swelling suspicious for fracture or cartilage injury. An MRI is recommended for this type of injury, as early surgery may be needed to manage the fracture or cartilage injury. If there is no major cartilage or bony injury, non-surgical treatment of the first time contact dislocation has a good success rate. After a second dislocation event, surgery is recommended to improve function and to decrease the risk of recurrence.

Non-contact dislocation (i.e., cutting or pivoting) hints towards underlying bone and soft tissue abnormalities that may predispose to further dislocation events. Several risk factors for recurrent dislocation have been identified, including younger age, open growth plates, sports injury, and anatomic abnormalities (i.e., flat kneecap groove, high patella). Surgery is indicated for recurrent dislocation to stabilize the knee and to prevent worsening soft tissue or cartilage injury. In this subset of patients, surgery may also be considered after the first dislocation.

To find a Physical Therapy Clinic located in the Treasure Valley – Boise Idaho to help with your knee pain call 208-367-3315!

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Liebensteiner MC, Dirisamer F, Balcarek P, Schoettle P. Guidelines for Treatment of Lateral Patella Dislocations in Skeletally Mature Patients. Am J Orthop (Belle Mead NJ). 2017. Mar/Apr;46(2):E86-E96.

Weber AE, Nathani A, Dines JS, Allen AA, Shubin-Stein BE, Arendt EA, Bedi A. An Algorithmic Approach to the Management of Recurrent Lateral Patellar Dislocation. J Bone Joint Surg Am. 2016. Mar 2;98(5):417-27. doi: 10.2106/JBJS.O.00354.