The tendons in the human body are made of strong fibrous tissue and connect the bones with the muscles. The patellar tendon transfers forces from the quadriceps to the anterior surface of the tibia, so that the knee can be extended.
Partial ruptures in the tendon make it difficult to walk and participate in daily activities. A total rupture of the patellar tendon is a serious injury that usually requires surgical treatment and subsequent physiotherapy to restore knee function.
The patellar tendon connects the lower pole of the patella to the upper part of the tibia and is essentially a joint that connects two different bones, the femur to the tibia.
The patella attaches to the quadriceps muscle through the quadriceps tendon. Working together, the patellar tendon, the tendon of the quadriceps and the quadriceps itself extend the knee.
The patellar tendon ruptures may be complete or partial.
Partial ruptures: Many ruptures do not extend to the entire length of the tendons. For example, when a rope is stretched along its length, some of its fibers are stretched excessively but the rope is still intact, in the sense that hasn’t broken yet.
Complete ruptures: A complete rupture cuts the tendon into two pieces. When the patellar tendon is completely ruptured, it gets detached from the patella. Without the integrity of the tendon, knee extension is impossible. Sometimes, a bone fragment along with the tendon may be detached at the rupture. But when the rupture is the result of a pathological condition, such as in tendonitis, then the rupture occurs in the middle of the tendon.
Injury: Patella tendon ruptures require very strong forces.
Falls: Immediate injury on the anterior surface of the knee, as occurs in a fall, is a frequent cause of ruptures. In this case, the rupture may be accompanied by an open wound.
Jumps: The patellar tendon is often injured when the knee is bent and the foot rests on the ground, such as during landing from a jump or during a jump.
Chronic conditions: A weak patellar tendon is more likely to rupture. Several causes can lead to tendon degeneration and weakness.
Tendonitis of the patellar tendon: Inflammation of the patellar tendon weakens the tendon and can even cause small ruptures. This condition, also called the jumper’s knee, often occurs in activities that require running or jumping. Injections of corticosteroids to treat this condition are not indicated, as they may lead to further weakening of the patellar tendon. These injections are avoided in or around the tendon area.
Chronic disease: Tendon weakness can even be caused by conditions that reduce blood flow to the tendon. These are:
- Chronic kidney failure
- Rheumatoid arthritis
- Systemic lupus erythematosus
- Diabetes Mellitus
- Chronic Infections
- Metabolic Disease
Use of Steroids: The use of corticosteroids and anabolic steroids to treat tendonitis has been found to lead to increased muscle and tendon weakness.
Surgery: Surgery on or around the patellar tendon, such as total knee arthroplasty or anterior cruciate ligament repair, may increase the chance of rupture.
When the patellar tendon is ruptured there is often a feeling of “tearing” or a “click” that the patient perceives. In most cases pain and edema follow and the patient cannot extend the knee.
Additional symptoms are:
- A palpable gap in the lower part of the patella where the patellar tendon is ruptured
- Bruising – Redness
- Local sensitivity
- The patella can be moved upward, over the thigh, because it is not held in place as it is pulled by the quadriceps tendon.
- Difficulty in walking, because the knee is unstable or loose
The treating physician will discuss with the patient the general state of their health and symptoms. He will then receive a detailed medical history. Questions may include:
- Has the patient previously had similar or other knee injury?
- Does he/she suffer from tendonitis of the patellar tendon?
- Are there any medical problems that may predispose to a knee or patellar tendon injury?
- Has the patient previously undergone knee surgery or anterior cruciate ligament rupture?
After completing the above procedure, the Orthopedist will examine the knee in detail. To determine the exact cause of the condition, the treating physician will check the joint extended. Although this part of the examination is painful, it is very important in the diagnosis of a patellar tendon rupture.
To confirm the diagnosis, the physician will order a series of tests, such as simple radiographs or magnetic resonance imaging.
X-rays: The patella moves out of position when the patellar tendon is ruptured. This is very evident in the lateral X-rays of the knee. Complete ruptures can only be confirmed with these shots.
Magnetic resonance imaging (MRI): This method can provide better images of soft tissues, such as the patellar tendon. Magnetic resonance imaging will depict the extent and morphology of the rupture. Often magnetic resonance imaging is required to exclude injuries with similar symptomatology.
The orthopedist will consider several things before heading to definitive treatment. These include:
- The type and size of the rupture
- The level of activity of the patient
- The age
Conservative treatment: Very small and partial ruptures respond very well to conservative treatment, which usually involves the use of splints and physiotherapy.
Immobilization: The treating physician may recommend the use of a splint, which will keep the knee extended to assist in the healing procedure. The patient will probably need crutches to avoid charging the affected leg for 3-6 weeks.
Physiotherapy: When the initial pain and edema subsides, physiotherapy can begin. Specific exercises can restore muscle strength and range of motion.
During splint use, the treating physician may suggest exercises to strengthen the quadriceps. Knee lifts are often recommended with the lower extremity extended. Over time, the physician will unlock the splint to allow wider range of motion. Gradual strengthening exercises will be recommended during healing.
Surgery: Many patients need to undergo surgery to restore knee function. The surgical treatment consists of suturing the tendon to the patella. Patients who undergo surgery report better results when surgery is performed as soon as possible after the injury. Quick treatment prevents tendon scarring and shrinkage.
Hospital Stay: Although the patellar tendon rupture suturing can be performed as a one-day outpatient procedure, it is preferred that the patient stays in the hospital for one night. This of course depends on the treating physician. The surgery is performed either under regional anesthesia (epidural) or even under general anesthesia.
Surgical Procedure: The tendons are restored by using sutures placed on the tendon, as well as on the bone, at its origin, with the surgeon properly adjusting the applied tension. This will restore the rupture to the pre-injury condition.
Newer technique: A new development in the field of repairing this type of injury is the use of anchors. Because it is a completely new technique, there is still not much data on its effectiveness.
In order to hold the patella in place and prevent the tendency of the materials to break, many surgeons use other materials to strengthen the suture, such as wires, which however need to be removed in a second surgery in the future.
If the tendon is significantly shortened prior to surgery, then reattachment can be a difficult task. In this case, a tendon graft may be used to lengthen the tendon. The latter may be an autograft or allograft.
Complications: The most common complications of patellar tendon repair include weakness and loss of movement. New ruptures can occur and the fixed tendon can be detached again. In addition, the position of the patella may be different after surgery. As with any surgery, other possible complications are: inflammation, trauma re-opening, thrombosis or even anesthesia problems.
Remedy: Some type of analgesia will be required after surgery, including ice pads and analgesics. Two weeks after surgery, the sutures will be removed by the treating physician.
In all likelihood, the knee will be protected by a splint or a long splint-boot. Initially, the doctor may recommend only minimal contact and no load-charging activities. Partial (50%) charge shall be permitted in 2-4 weeks, while full charge is safe only after 4-6 weeks.
Over time, the orthopedist can loosen the splint to allow wider range of motion. Strengthening exercises will be added later to the original plan. Complete recovery takes about 6 months, although some patients claim that it took them 12 months to reach their desired goal.
Most patients return to pre-injury levels in terms of lifestyle habits. There are many who report knee stiffness, while most regain full range of motion. In case of an athlete, the surgeon must examine the injured knee before allowing the patient to return to sporting activities. The goal is for the affected leg to reach 85-90% of normal functionality. In addition to all of the above, the treating physician will work to restore balance, endurance, and check for persistent edema.