On Monday night, the San Antonio Spurs bowed to the Golden State Warriors in Game 4 of the Western Conference Finals. It wasn’t much of a contest. After another stellar regular season, early playoff injuries robbed the Spurs of veteran point guard, Tony Parker (quad tendon rupture), and the electric small forward, Kawhi Leonard (ankle sprain). On Saturday, when Spurs’ center/power forward, David Lee partially tore his patellar tendon, it was all but over. This wasn’t the first time that the 34 year-old Lee underwent significant post season surgery. He’d had a torn hip flexor repaired in May of 2013 having seen very limited playoff action once sustaining the injury the month prior.
The Patellar Tendon & Extensor Mechanism
Because tendons connect muscle to bone, and ligaments connect bone to bone, the patellar tendon is actually misnamed. The structure is actually a ligament, connecting the base of the patella (kneecap) to a prominence at the upper tibia of the lower leg. The patellar tendon is one component of the extensor mechanism of the knee.
The quadriceps muscle – which attaches to the patella via the quad tendon – is the featured player of the extensor mechanism. However, the functional unit is also comprised of bands of fibrous tissue known as the medial & lateral retinaculum, which help maintain the alignment of the patella (kneecap), as well as ligaments that provide patellar stability by connecting the patella to the femur and tibia (patellofemoral and patellotibial ligaments). The tibial tubercle, the prominence on the upper tibia that serves as the attachment for the patellar tendon completes the extensor mechanism.
Ruptures of the extensor mechanism occur either to the quadriceps tendon or patellar tendon and may be complete or partial. Patellar tendon ruptures generally occur in those younger than 40 years of age, while quad tendons are more likely to rupture in those over 40. Prolonged steroid use (resulting in tendon weakness) is thought to increase the risk of complete rupture, as are chronic diseases that adversely impact blood supply, such as Diabetes, Rheumatoid Arthritis, Lupus, or infection.
Patellar Tendon Ruptures
When either the quad or patellar tendons are completely ruptured, the knee cannot be actively straightened at all. With a partial tear, it is generally possible to extend it at least somewhat.
Most ruptures of the patellar tendon occur when the knee is bent and subject to more demand than it can tolerate. Ruptures occur more frequently at the upper part of the tendon and its attachment to the patella than at the lowermost portion where it attaches to the tibia. A patellar tendon rupture may also be referred to as an avulsion, which is the term used to describe the tearing away of a body part. In the case of a tendon tear, a portion of the attaching bone may be torn away as well. Without the tendon to anchor it, when someone has a torn patellar tendon, the kneecap will ride upward and remain there. Interestingly, there is a greater incidence of patellar tendon ruptures amongst those of African decent. The reason for this is not absolutely clear.
Complete rupture of the patellar tendon requires surgical repair, and surgery is best if performed promptly to optimize outcomes. Partial tears may heal sufficiently depending on the degree of disruption and the demands placed on the muscle tendon unit. Newer operative procedures allow patients to avoid prolonged immobilization in a cast and work on mobility of the knee in the post-operative period. This generally accelerates recovery. However, healing and rehab is a process that cannot be rushed. A gradual restoration of full range of motion, soft tissue and muscle flexibility, strength and endurance as well as balance and agility is all a part of that process.