default header

Knee Tendon Rupture

Background and Etiology

The knee is the largest joint in the body. It is built for weight bearing, stability and mobility. The knee complex is composed of four bones and three osseous bone-to-bone joints. The most common injury or condition of the knee is knee tendonitis. There are several groups of tendons that attach near and control the knee. A tendon is the cord-like part of the muscle that attaches the muscle to the bone. The two primary tendons located in the front of the knee are the patellar tendon and the quadriceps tendon. Although rare, it is possible to rupture both the patellar and quadriceps tendons.

Patellar and Quadriceps Tendon

The patellar tendon is the large tendon in the front of the knee that runs from the patellar (knee cap) to the tibia (lower leg bone). The patellar is located within the quadriceps tendon. The quadriceps tendon is formed where the four quadriceps muscles on the front of the thigh meet. This complex is called the extensor mechanism of the knee. It is responsible for straightening the knee and plays a vital role in walking, stair climbing, running and jumping activities.

Quadriceps Tendon Rupture

Quadriceps tendon tears are more common than patellar tendon tears and can be either partial or complete. Partial tears, if small, can sometimes be managed conservatively without surgery. Surgery will be recommended for complete tears.

Causes

  • An injury to the knee or a direct blow to the tendon.
  • When a heavy load of weight and stress is applied while the foot is planted and the knee is bent. This is common while landing from a jump, for example while playing basketball.
  • As a result of a fall where an individual lands awkwardly or directly on the knee.
  • Laceration of the tendon
  • Weakness of the quadriceps muscle in people with quadriceps tendonitis places increased stress on the quadriceps tendon. This is common in individuals who participate in athletic activities that require jumping like volleyball or basketball.
  • Steroid use has been linked to quadriceps tendon weakness
  • Certain systemic diseases have been associated with quadriceps tendon weakness.

Symptoms of Quadriceps Tendon Tears

  • Knee pain and swelling or feeling that the knee has “given out” after falling or stumbling.
  • Possible audible pop when the knee is injured.
  • Patient may have a history of prior knee pain or tendonitis, and may be active in sports where jumping is necessary.
  • Swelling, tenderness and possible discoloration above the patellar.
  • Indentation above the patellar where the torn tendon may be present.
  • Difficulty moving around or walking.
  • Individual has difficulty or is unable to straighten their knee all the way.
  • MRI can confirm disruption or tear in the tendon.

Patellar Tendon Rupture

The patellar tendon runs from the lower part of the patellar to the tibia (lower leg bone.) It attaches the quadriceps muscle to the lower leg and transfers the forces of the quadriceps. This allows for knee extension or straightening. Patellar tendon rupture is rare and usually occurs in individuals below the age of 40 as a result of an athletic injury.

Causes

  • The progression of or the final result of longstanding patellar tendonitis or an overuse injury.
  • A heavy load of weight or stress is applied while the foot is planted and the knee is bent. This is common while landing from a jump, for example while playing basketball.
  • A sudden deceleration or stopping motion can sometimes rupture the patellar tendon.
  • Injection of steroids to the patellar tendon or the excessive use of steroids has been known to weaken the tendon and make it susceptible to rupture.
  • An injury or direct blow to the patellar tendon.
  • Laceration of the patellar tendon.
  • Certain systemic diseases have been associated with patellar tendon weakness.
  • Patellar tendon ruptures can also occur as post surgical complications (for example following an ACL reconstruction or a total knee replacement.)

Symptoms of a Patellar Tendon Tear

  • Immediate pain at time of injury.
  • A loud audible pop at the time of injury.
  • Swelling and bruising or ecchymosis is present in the front of the knee.
  • There is a gap where the tendon has ruptured
  • It is difficult to put weight on the leg.
  • Inability to straighten the knee actively by yourself.

Treatment of Quadriceps and Patellar Tendon Rupture

Early diagnosis and treatment is the key to a successful outcome for both quadriceps and patellar tendon ruptures. If diagnosis or treatment is delayed the integrity of the healing tissue can be compromised as a result of scarring and decreased blood flow. Surgical repair followed by structured and aggressive physical therapy is the treatment of choice for complete ruptures. In the case of a small partial quadriceps tendon tear conservative treatment without surgery is an option.

Partial (small) Quadriceps Tendon Tear

  • Immobilization of the knee for 3-6 weeks to rest and promote healing. Individual will be placed in an immobilizer or brace and will move around with crutches to keep weight off of the leg.
  • Physical Therapy: following the period of immobilization your physician will decide when you are ready for physical therapy. Treatment will emphasize gradual weaning off the immobilizing device, increasing weight bearing, restoration of knee range of motion and strengthening of the quadriceps. It is important that the physician and therapist communicate during the early stages and progress your recovery program based on the principles of healing so as not to compromise the quadriceps tendon.
  • Patient will be progressed to more functional activities as normal knee range of motion and strength is restored.

Complete Quadriceps and Patellar Tendon Rupture

  • Immediate surgical repair of the tendon is indicated in complete tears. Delaying surgery can lead to shortening of the tendon, formation of scar tissue and decreased blood flow, which can lead to a poor outcome.
  • In the case of the quadriceps tendon the surgeon will suture or anchor the tendon to the top of kneecap or patellar.
  • With patellar tendon repairs the tendon is sutured together anchored to the lower part of the patellar or kneecap.
  • Following surgery your knee will be put in an immobilizing device and you will be instructed to use crutches to limit weight bearing and protect the joint.
  • Over the next 2-4 weeks weight bearing will be increased and physical therapy will be initiated.
  • The surgeon will determine the physical therapy timeline and program.
  • Physical Therapy: treatment will emphasize gradual weaning off the immobilizing device, increasing weight bearing, restoration of knee range of motion and strengthening of the quadriceps. It is important that the physician and therapist communicate during the early stages and progress your program based on the principles of healing so as not to compromise the quadriceps or patellar tendon.
  • Patient will be progressed to more functional activities as normal knee range of motion and strength is restored.

Physical therapy for a tendon rupture must remain conservative at the onset in order to protect the repair. Emphasis will be on rest, tendon protection, reducing the inflammation and increasing the blood circulation for healing. Following the surgeon’s timeline and protocol, a program of progressive weight bearing, stretching and strengthening will be initiated.

Physical Therapy Interventions

Common Physical Therapy interventions in the treatment of Knee Tendon Rupture include:

  • Manual Therapeutic Technique (MTT): hands on care including soft tissue massage, stretching and joint mobilization of the knee and patellar by a physical therapist to improve joint mobility and range of motion of the knee. Use of mobilization techniques also helps to modulate pain.
  • Therapeutic Exercises (TE) including stretching and strengthening exercises to regain range of motion and strengthen the quadriceps and muscles of the knee and lower extremity.
  • Neuromuscular Reeducation (NMR) to restore stability, retrain the lower extremity and improve movement techniques and mechanics (for example, running, kneeling, squatting and jumping) of the involved lower extremity to reduce stress on the tendons in daily activities. Taping, strapping or bracing may be indicated to rest tendon and promote healing.
  • Modalities including the use of ultrasound, electrical stimulation, ice, cold, laser and others to decrease pain and inflammation of the involved tendon and burse.

Prognosis

If repair and treatment are initiated immediately, individuals with patellar and quadriceps tendon tears generally do well. Delay can result in the formation of scar tissue and retraction of the tendons. Other factors that can affect recovery are:

  • Age: Older individuals are generally weaker and take longer to heal affecting the functional outcome.
  • Strength: Individuals who are strong and in good condition prior to the injury generally do better following surgical repair.
  • Tissue: Tissue quality prior to the surgical repair will effect healing and recovery following surgery. Poor circulation and presence of scar tissue will interfere with the healing process.

The healing time for a tendon repair will take up to 8-12 weeks but restoration of function and ability to accept full activity, load and stress can take up to one year.