Patella (Kneecap) Stabilisation
The kneecap can be the cause of many symptoms in the knee, the majority of which can be treated without surgery.
However, when the kneecap is unstable or dislocates surgery may be helpful.
In general, when the kneecap dislocates more that once or continues to feel unstable Mr Sethi would discuss potential surgical treatment to prevent pain, instability and future degeneration in the joint.
Medial Patello-Femoral Ligament (MPFL) Reconstruction
The MPFL is almost always torn at the time of a patella dislocation.
If the ligament doesn’t heal after the initial dislocation, ‘delayed’ repair is not successful.
Mr Sethi routinely reconstructs the MPFL using a graft from the hamstring tendons from the back of the thigh.
Following general anaesthesia (you are asleep), a tight inflatable band (tourniquet) is wrapped around your thigh to restrict bleeding into and around the knee during the operation. A telescope with a camera (arthroscope) is then introduced into your knee through 2 small incisions (approximately 1cm long) which allows a thorough examination of the knee / patella joints and assessment of patella tracking.
Once the arthroscopy has been done the graft (hamstring tendon) is collected (harvested), usually from the same leg.
An incision is then made over the inner aspect of the femur the loose end of the graft is passed into this tunnel. Another incision is then made on the inside border of the patella and the graft is secured in place. The tracking of the patella and the limits of the side-to-side glide are confirmed by the camera on the arthroscope.
The wounds are then closed and a bandage is applied to the knee.
Patients who undergo a MPFL reconstruction can put weight through their leg immediately after surgery, though crutches will be required for the first couple of weeks. Knee motion is encouraged immediately and the physiotherapists will ensure that a full range of motion of the knee is regained in the first few weeks. The use of a stationary bike is also initiated at 6 weeks after surgery and endurance and agility exercises are initiated at 3 months after surgery. Most patients without any arthritis in their kneecap can return to full sporting activities at between 5-6 months after surgery.
What are the risks?
Potential risks and complications of surgery
Anterior knee pain / Quadriceps wasting - Surgery that involves the patella frequently causes anterior knee pain, with subsequent
wasting of the quadriceps muscle. This may cause some difficulty with kneeling, squatting etc. Your physiotherapist will use techniques to reduce this pain and strengthen the muscles.
Blood clots (Deep Vein Thrombosis) - These can occur in the lower legs following such surgery and can occasionally enlarge and
move through the blood stream to the lungs (pulmonary embolus) making it difficult to breath (rare). Early movements are important to help prevent this from occurring.
Numbness - You may experience some mild numbness on the anterior of your shin, close to your scars following surgery.
Swelling / Bleeding into the knee - Post-operatively blood can collect in the knee joint. In most cases it will be absorbed by the joint itself.
Infection- The wound sites may become infected - this usually settles with antibiotics. Very occasionally a further operation may be needed. Deep infection within the knee joint is very rare.
Unsightly scarring of the skin - Most wounds heal to a neat scar but thickened, red and painful scars occasionally occur, especially in Afro-Caribbeans.
Damage to the skin under the tourniquet - This may require dressing or rarely surgery. There may also be numbness of the skin which is usually temporary.
Graft rupture - The graft may rupture after further trauma. Further surgery may be necessary.
Loss of balance reactions /proprioception (your ability to balance) - Despite it being functionally stable, the knee may feel different for quite sometime. Regular balance exercises and a tubigrip may reduce this feeling.
Severe pain - Pain, stiffness and loss of use of the knee (complex regional pain syndrome) is rare and the cause is unknown. If this happens you may need further treatment including painkillers and physiotherapy. The knee can take months or years to fully recover.
Tibial Tuberosity Transfer
Patients who have patellofemoral instability (unstable patella / kneecap) may be candidates for a tibial tubercle osteotomy. In this circumstance, the tibial tubercle is either elevated or moved to try to restore a more normal position of the patella.
A thorough history and examination is necessary to determine which patients may be candidates for a tibial tubercle osteotomy. In patients with patellar instability who also have a Tibial Tubercle-Trochlear Groove (TT-TG) distance of 2 cm or greater, a tibial tubercle osteotomy may be indicated.
Description of a Tibial Tubercle Osteotomy
In a tibial tubercle osteotomy, the tibial tubercle and the patellar tendon are detached and moved to a pre-calculated new position on the anterior tibia. The moved tubercle is held in place by two screws and washers. Usually, patients have a secure fixation which allows for early knee motion of up to 90 degrees of knee flexion.
With this procedure, patients need to be on crutches for 6 weeks and the osteotomy itself can take up to 4 months to heal before significant stress can be placed across the quadriceps mechanism in order to make sure that they do not go on to have a full fracture of their tibia. This complication is rare, a sudden fall or stress to the knee could put the area of the tibial tubercle osteotomy under significant stress, which could lead to a fracture.