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PATELLAR INSTABILITY                                         KANDILNOTES


  • Patellar instability, or kneecap instability, occurs when the kneecap doesn't stay in its groove with knee motion

  • Primary structure injured is the medial patellofemoral ligament (MPFL) which connects the thigh bone to the kneecap and keeps it in its groove

  • Usually occurs in patients in their teens or twenties

  • There are two main types of patellar instability

  • Traumatic: occurring from an injury

  • Generalized laxity: occurring in patient with lax soft tissues. Includes habitual dislocators

  • Up to 50% chance of recurrence in young patients with kneecap dislocation


  • Kneecap dislocations usually occur after noncontact twisting injuries during sports, or less commonly a direct blow to the kneecap

  • Risk factors include generalized laxity, previous dislocation, and other anatomic factors such as patella alta, trochlear dysplasia, etc.


  • Patellar dislocations are almost always associated with immediate pain and swelling

  • Instability of the kneecap is common after patellar dislocations

  • Anterior knee pain


  • Patellar instability patients who are first time dislocators without complicating features are often treated with a course of anti-inflammatories, rest, bracing, followed by a course of physical therapy. Physical therapy is focused on strengthening the core, hip, and quadriceps

  • Patients with multiple dislocations and pain are usually treated with surgery often consisting of an MPFL reconstruction. Depending on other anatomic factors, other procedures may be added including cartilage procedures, bony osteotomy, etc.


  • The best way to prevent patellar instability is to work on strengthening the core, hip, and quadriceps

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