The kneecap or patella is located in the front of the knee and articulates with the femur in a groove called the trochlea groove. It actually lies within the tendon of the quadriceps muscle and due to this, how the patella moves and tracks is determined by how the quadriceps muscle pulls. This matching of puzzle pieces (bony restraint) along with soft tissue stabilizers (mainly the medial patella femoral ligament (MPFL)), holds the patella in place and helps it to run smoothly through the centre of the knee.
Due to certain predisposing factors, such as a shallow trochlea groove or high riding patella, or due to trauma, the patella can dislocate laterally (be pushed to the outside of the knee joint). This causes extreme pain and the knee swells considerably. At the time of injury, the medial soft tissue supporting structures, including the MPFL, are torn.
The majority of cases can be treated conservatively with 75% of first time patella dislocations, not progressing to further dislocations.
Conservative treatment entails:
- RICE (Rest, Ice, Compression, Elevation) for about the first 10 days. Analgesia and anti-inflammatories are used to alleviate the symptoms. A brace may be used in the initial 2 weeks until the pain has settled.
- A graduated rehabilitation program once the pain has settled (usually from 2 weeks on). This entails obtaining a full range of movement (soft tissues heal better with movement) and rehabilitating the quadriceps muscle.
Surgery is needed in the following scenarios:
- Recurrent patella dislocations (more than 2 dislocations)
- When a large piece of cartilage with or without is pulled of the patella by the MPFL. This can lead to locking and a loose body in the knee.
In general the procedure performed is to reconstruct the MPFL using one of your hamstring tendons thereby stabilising the patella. The chondral lesion or loose body is treated on its own merits at surgery with either removal or fixation if able.
Patella tendonitis is inflammation that occurs in the patella tendon (just under the kneecap). It is also known as jumper’s knee. It is caused by overuse and putting too much strain through the patella tendon and is common in jumping sports (such as tennis, volleyball) and running. It can however occur due to an acute injury (sudden hard contraction of the quadriceps muscle causing a tear in the tendon).
- Ice and anti-inflammatories
- Avoid precipitating cause
- Rehabilitation is cornerstone of treatment with specific attention paid to eccentric quadriceps training and core stability exercises. This is the most important.
- Cortisone injection into the inflamed area
- PRP injections (see PRP section)
- Extra-corporeal shock wave therapy
- Surgery (rare)
These injuries heal better with movement so rest is not advocated.