Dislocated Kneecap: Medical Reduction, Rehabilitation, and Prevention

How do you put a kneecap in place?

Putting a kneecap (patella) back in place after a dislocation is a medical procedure that should only be performed by a trained healthcare professional. Attempting to self-reduce a dislocated kneecap can lead to further injury and complications.

Understanding Patellar Dislocation

A patellar dislocation occurs when the kneecap slips out of its groove (the trochlear groove) at the end of the thigh bone (femur). This is a painful injury that can result in significant instability and damage to the surrounding structures.

• Anatomy of the Knee Joint: The patella is a sesamoid bone embedded within the quadriceps tendon, acting as a pulley to increase the mechanical advantage of the quadriceps muscle. It glides within the trochlear groove during knee flexion and extension. The medial patellofemoral ligament (MPFL) is a crucial stabilizer, preventing the patella from dislocating laterally.
• Causes of Dislocation:
  • Traumatic Injury: A direct blow to the knee or a sudden twisting motion of the leg, especially when the foot is planted and the knee is slightly bent.
  • Anatomical Predisposition: Shallow trochlear groove, patella alta (high-riding patella), genu valgum (knock-knees), muscle imbalances (e.g., weak vastus medialis obliquus or tight lateral retinaculum), or general ligamentous laxity can increase susceptibility.
• Symptoms:
  • Sudden, severe pain in the knee.
  • Visible deformity, often with the kneecap shifted to the outside of the knee.
  • Inability to straighten or bend the knee.
  • Swelling and bruising around the knee joint.
  • A popping sensation at the time of injury.

The Critical Importance of Professional Medical Intervention

Given the complexity of the knee joint and the potential for associated injuries, professional medical intervention is paramount for a dislocated kneecap.

• Why Self-Reduction is Dangerous:
  • Further Injury: Attempting to force the patella back can damage the articular cartilage on the back of the kneecap or the trochlear groove, tear ligaments (especially the MPFL), or cause fractures.
  • Incomplete Reduction: The patella might appear to be back in place but could be misaligned, leading to ongoing pain and instability.
  • Misdiagnosis: Other severe injuries, such as an osteochondral fracture (a piece of bone and cartilage breaking off), can occur simultaneously and require specific treatment that self-reduction would not address.
• When to Seek Immediate Medical Attention: If you suspect a patellar dislocation, or any significant knee injury, seek emergency medical care immediately. Do not attempt to move the leg or force the kneecap back into place. Keep the leg as still as possible and apply ice if available.

The Medical Reduction Process

Healthcare professionals follow a systematic approach to safely reduce a dislocated patella.

• Assessment and Diagnosis:
  • A thorough physical examination to assess the position of the patella, swelling, and range of motion.
  • X-rays are crucial to confirm the dislocation, rule out any associated fractures (e.g., osteochondral fractures), and evaluate the knee's alignment. Sometimes, an MRI may be ordered to assess soft tissue damage, particularly to the MPFL.
• Reduction Techniques:
  • The patient is often given pain medication and sometimes sedation to relax the muscles around the knee, making the reduction easier and less painful.
  • The medical professional will typically perform a gentle manipulation. This often involves slowly extending the knee while applying gentle pressure to the side of the patella to guide it back into the trochlear groove. The goal is to reverse the path of dislocation.
  • A noticeable "clunk" may be felt or heard as the patella returns to its correct position.
• Post-Reduction Care:
  • After reduction, the knee is typically immobilized in a brace or splint for a period (e.g., 2-4 weeks) to allow initial healing and reduce the risk of re-dislocation.
  • Pain management and RICE (Rest, Ice, Compression, Elevation) protocols are initiated.
  • Referral to physical therapy is almost always recommended to prevent recurrence and restore full function.

Rehabilitation and Prevention

Effective rehabilitation is crucial after a patellar dislocation to regain strength, stability, and prevent future episodes.

• Goals of Rehabilitation:
  • Reduce pain and swelling.
  • Restore full knee range of motion.
  • Strengthen the muscles around the knee and hip.
  • Improve proprioception (body's sense of position and movement).
  • Return to prior activity levels safely.
• Key Exercises (Guided by a Physical Therapist):
  • Quadriceps Strengthening: Emphasis on the vastus medialis obliquus (VMO) to help stabilize the patella. Exercises like straight leg raises, terminal knee extensions, and inner range quads.
  • Hip Strengthening: Strengthening the hip abductors and external rotators (e.g., glute medius, glute max) helps control lower limb alignment and reduce stress on the knee.
  • Hamstring and Calf Strengthening: To ensure overall lower limb balance.
  • Balance and Proprioception Training: Single-leg standing, wobble board exercises.
  • Stretching: Addressing any tightness in the quadriceps, hamstrings, or IT band.
• Preventative Measures:
  • Address Muscle Imbalances: Work with a physical therapist or trainer to identify and correct any strength or flexibility deficits.
  • Proper Movement Mechanics: Learn and practice correct form for exercises and sports-specific movements, avoiding excessive valgus collapse (knees caving inward).
  • Appropriate Warm-up and Cool-down: Prepare the muscles for activity and aid recovery.
  • Consider Bracing: For individuals with recurrent dislocations or during return to sport, a specialized patellar stabilizing brace may be recommended.

When is Surgery Considered?

While many patellar dislocations are managed non-surgically, surgery may be recommended for recurrent dislocations or when specific anatomical issues are present.

• Indications:
  • Recurrent patellar dislocations despite conservative management.
  • Significant osteochondral fractures that require fixation or removal.
  • Severe anatomical abnormalities contributing to instability (e.g., trochlear dysplasia, patella alta).
  • Complete rupture of the MPFL.
• Types of Procedures:
  • Medial Patellofemoral Ligament (MPFL) Reconstruction: The most common surgical procedure, involving reconstructing the torn MPFL using a graft (from the patient or a donor) to restore medial stability to the patella.
  • Tibial Tubercle Osteotomy: Involves cutting and repositioning the bony prominence on the shin bone (tibia) where the patellar tendon attaches, to improve the tracking of the patella.
  • Trochleoplasty: A procedure to deepen the trochlear groove if it is too shallow.

Conclusion and Key Takeaway

A dislocated kneecap is a serious injury requiring immediate medical attention. While the idea of "putting it back in place" might seem straightforward, the process of reduction, and the subsequent rehabilitation, is complex and best handled by trained medical professionals. Prioritizing proper diagnosis, safe reduction, and comprehensive rehabilitation is essential for restoring knee function and preventing future instability.