Patellar dislocations can be categorized as either being acute or chronic. With acute dislocations there is excessive lateral displacement of the patella (knee cap moves outwards) and usually occurs in the athlete population. In males, it is associated with direct trauma from a sport or activity. With chronic dislocations, repeated episodes of dislocation occur rather than an isolated incident and it may be due to abnormal structural or dynamic factors in the person.
When the patella dislocates it moves (tracks) laterally or to the outside of the knee. In chronic or recurrent cases, it is more prevalent in the teenage female population often due to abnormal alignment, athletes, and ⅓ involve both extremities (bilateral).
The dislocated patella immediately causes acute pain, swelling due to tearing of the medial stabilizing structures (medial capsule) and there is medial joint line tenderness due to stretching of the medial structures. There is also limited range of motion (ROM) and an audible snapping or popping occurs at the time of injury. With recurrent dislocations, it is common to see atrophy of the Vastus Medialis Oblique (VMO) which is the medial portion of the distal quadriceps. This is a critical component of keeping the patella in its place or stabilized. I like to tell my patients that the patella is like a train on a train track when you bend or extend your knee. It follows a specific path and when the surrounding structures are not doing its job the patella (train) can go off its tracks. The VMO plays a large role in this as does the IT Band.
So once you are diagnosed with a patellar dislocation, what happens next ? What are the treatments?
It is important to reduce the amount of activities involving high or prolonged patellofemoral compressive loads by modifying your activities and selecting alternative ones in the meantime until you are back to 100%.
Pharmaceutical management may be necessary and prescribed by your doctor in some cases if there is inflammation and swelling, such as taking NSAID’s (Nonsteroidal anti-inflammatory drugs), iontophoresis or cortisone injections.
Physical therapy is likely the best option to treat the injury and if it’s an acute type of dislocation, therapy prevents this from becoming a chronic case in the future. Make sure to go to a state- licensed physical therapist who has training in manual therapy.
Your physical therapist will first try to get the swelling and inflammation down by using such modalities as ice, iontophoresis, ultrasound, and manual therapy techniques such as myofascial release or massage. Another component that is often overlooked is the importance of the patella to obtain normal movement again by using patellar mobilizations which is performed by the physical therapist. This allows the patella to move properly when the knee is flexed or extended. Once the pain and swelling subsides it is critical that strengthening exercises for the quadriceps and VMO is targeted with specific exercises. Also stretching the hamstrings, quadriceps and especially the IT Band is very important.
Next, educating the patient and correcting the soft tissue biomechanics is important. It may be necessary to correct foot pronation with orthotics, train supinators, correct imbalances in strength and flexibility and taping the foot. Studying the sport you may be participating in on a regular basis is a good idea. Pay attention and analyze your body mechanics using video recording. Make sure proper training techniques are being used. Bracing and patellar taping will be a possible option once you return to your activity and sport.
Author: Avi Bregman, PT, MPT