The San Antonio Spurs lost point guard Tony Parker to a quadriceps tendon tear in the fourth quarter of game two in their series against the Rockets on Wednesday. Parker, who now faces surgery, was a big reason that San Antonio evened up the series that night at one apiece. Like the Clippers’ loss of Blake Griffin to a season-ending playoff injury, this one could cost the Spurs the ability to advance.

At age 34, Parker’s numbers this season were at a career low (10.1 ppg), though he’d ramped that up to an eight game playoff average of 15.9 on 53 percent shooting. Now he faces a long road back and, with his age and overall declining regular season numbers, a questionable return to the NBA.

The Extensor Mechanism

The quadriceps is a vital part of what is called the extensor mechanism of the knee, with the muscles acting in unison for that purpose. One of the four muscles, the Rectus Femoris (RF) also serves as a hip flexor because of its origin at the pelvis.

The extensor mechanism includes much more than just the quadriceps muscle and the quad tendon. It 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). Another important ligament in the extensor mechanism is really misnamed – the patellar tendon – which connects the base of the kneecap to the tibia of the lower leg. The final component is the tibial tubercle, a prominence on the upper tibia that serves as its attachment.

The Quadriceps

The four muscles of the quad are the Rectus Femoris (RF), the Vastus Medialis (VM), the Vastus Lateralis (VL), and the Vastus Intermedius (VI). The lowermost fibers of the VM are more horizontal in their orientation, and are traditionally known as the VMO (Vastus Medialis Obliquus). In addition to their role as knee extenders, these fibers have a distinct function in helping to maintain patellar alignment. A relatively new study points to the fact that a fifth muscular component, the Tensor Vastus Intermedius, also contributes to the quad tendon.

The Quad Tendon

Tendons connect muscle to bone enabling the muscles to function. Though the quad is made up of distinct muscles with differing attachments at the pelvis, hip region and femur (thigh bone) the tendons fuse to form a layered insertion at the patella.

The majority of quad tendons are three-layered, though studies show some variability. The quad tendon inserts at the base and sides of the patella in addition to having fibers that attach to the patellar ligament.

Quad Tendon Rupture

Quad tendon tears are painful injuries that are not as common as those of the patellar tendon in younger athletes (less than 40 years of age). They can be either partial or complete (rupture), and occur far more often amongst men than women. Rupture may be associated with weakened tissue (such as with a history of prior injury or tendinitis) and may be due to diminished circulation in the area. Increased risk is also a factor with a history of local cortisone injections, and medical issues such as diabetes, gout and others.

Injury generally occurs on a loaded limb with the foot planted and the knee in some degree of flexion (bent). The specific location of a tear is reported to correspond with the amount the knee is bent at the time it is injured.

A person is not able to walk following quad tendon rupture, as the ability to extend the knee is lost. After partial rupture the knee can be extended, though not fully. This is known as an extensor lag.

Rupture entails bleeding into the joint (hemarthrosis) that is often experienced as a burning sensation, and swelling is present. A complete rupture must be treated surgically to restore function. The tendon is repaired as well as anchored to the bone. It is preferable for surgery to take place within a week after injury in order to prevent retraction of the tissue.

There are various protocols for treatment following surgery. Some entail periods of immobilization for four to six weeks during which a hinged brace progressively restricts the amount of bending that is permitted. This allows the quad tendon to heal without being unduly stretched. Others involve earlier mobility and functional rehab.

Passive and active range of motion activities are important either way. Full weightbearing is now recommended, though with a progression from crutches to without, as pain and function allow.

Soft tissue mobilization is employed throughout to minimize adhesive scarring and restriction. Restoring strength is paramount as is restoring range of motion, muscle flexibility and ultimately, muscle endurance and power.

Studies done comparing the more conservative post-op approach with that of earlier functional rehab show no appreciable difference in outcomes. This affirms the safety of the latter.

In the case of a partial rupture, treatment is often non-surgical, involving immobilization and therapy to preserve/restore joint mobility followed by addressing other facets of muscle function as noted above.

More specifics regarding quad tendon rupture and surgery can be found here.

About the author

Abby serves as the Injury Expert for CBS New York where, since 2010, her Injury Breakdown Blog examines injuries in professional sports. She also blogs on health & fitness as well as sports injuries for Huffington Post, and Recovery Physical, where her blog earned a top ten mention for physical therapy blogs in 2012 @ In a ranking of the Top 30 Healthcare Blogs for 2012, Top Masters in Healthcare also rated Abby’s blog in the top three in Physical Therapy! Abby is the founder of Fit-Screen and she welcomes your comments and questions!