Patellar tendonitis, also known as jumper’s knee, patellar tendinopathy or tendinitis is an overuse injury that affects the knee and is usually a result of the patellar tendon being overstressed. Patella tendinopathy can be a debilitating disease and results in prolonged absence and potential retirement from sports.
Prevalence & risk factors of patellar tendonitis
Patellar tendonitis usually occurs in those who are relatively young (between 15 to 30 years old), in athletes, especially men who are involved in sports such as basketball, volleyball, track and field jumping events, tennis, and football which requires repeated use of the patellar tendon.
These sports require repeated bursts of energy for jumping, landing, cutting and pivoting. Repetition of this activity can cause damage and change in the tendon. It has been reported to be the most common injury in volleyball, reaching as high as 40% among high-level volleyball players.
It is one of the most common injuries in sports and up to 40% of professional players have experienced symptoms of this condition during their career. It was also found that chronic patellar tendinopathy leads to athletes abandoning their careers and still suffer mild but long lasting symptoms in a 15-year follow-up study.
Symptoms of patellar tendonitis
Patients usually present with anterior knee pain that is localized to the inferior pole of the patella. It may be described as a sharp and aching pain. The pain is also aggravated by activities that require the patient to jump, land after jumping, running and sometimes prolonged sitting. The pain is gradual in its onset and increases with activity.
Localized tenderness is found over the inferior pole of the knee and it may feel stiff in the morning. The affected tendon may also appear thickened compared to the unaffected side.
Other associated symptoms include swelling due to inflammation of the tendon, either at the superior or inferior pole of the kneecap, crepitus or the occurrence of the knee “giving way” or momentary weakness.
Diagnosis for patellar tendonitis
The diagnosis of patellar tendonitis is usually made via the patient’s history and examination of the patient. Palpation of the knee was found to be reliable in identifying patellar tendonitis. It is important to rule our other knee tendon disorders that may have a similar presentation and this can be aided with the use of an MRI scan around the knee area, computed tomography (CT) scan, ultrasound or a standard radiograph test.
Classification for jumper’s knee (patellar tendonitis) include:
Stage 0 – No pain
Stage 1 – Pain only after intense sports activity; no undue functional impairment
Stage 2 – Pain at the beginning and after sports activity; still able to perform at a satisfactory level
Stage 3 – Pain during sports activity; increasing difficulty in performing at a satisfactory level
Stage 4 – Pain during sports activity; unable to participate in sport at a satisfactory level
Stage 5 – Pain during daily activity; unable to participate in sport at any level
Treatment for patellar tendonitis
The pain-rest-reinjury cycle is important in regards to patellar tendinopathy treatment. It is vital that patients do not return to sport or vigorous activities before there is adequate healing of the knee tendon. Conservative management is usually recommended in phases 1 to 3.
Patellar tendonitis in its early stages is usually treated through:
- restriction or modification of activity
- applying ice packs
- using analgesics or anti-inflammatories
The non-operative treatment of patellar tendonitis may not be effective in all cases despite months of treatment depending on the health of the knee.
In patients with phase 1, treatment includes adequate warm up, cryotherapy after sports, using non-steroidal anti-inflammatory drugs (NSAIDs) as an anti-inflammatory and pain relief, bracing, and strengthening exercises.
In phase 2, moist heat before an activity is added to phase 1 treatment protocol. Corticosteroid injections are no longer administered as it has been associated with detrimental side effects and have no significant improvement. Corticosteroid injections can also provide pain relief leading to the continuation of damage on the tendon.
In phase 3, the phase 2 protocol is used with the addition of prolonged rest. It is also at this stage that surgery is considered.
Studies comparing surgical and conservative treatment found that both groups showed significant improvement over a twelve-month period with no statistical significance between the two groups.
Due to the long time needed for patients to recover for both surgical and conservative therapy, a study was conducted on arthroscopic (endoscopic surgery on the joint) surgery and patients were able to return to their activities within two months in the majority of cases.
There are multiple types of open surgical procedures that can be done for patellar tendonitis but the most common one involves the open excision of the diseased portion of the patellar tendon. The negative aspects of an open surgery are not related to the success rate but rather the amount of time needed for rehabilitation
The time to recover post open surgery can range from six to ten months. With arthroscopic surgery, studies have reported up to 85% of symptom improvement, a return to sporting function from 46% to 85% of patients and the time taken to return to activities was found to be between two and six months.
Exercise for patellar tendinopathy
Rehabilitative exercise is usually recommended once adequate healing of the knee tendon is achieved. Some of the stretches that can help improve knee health, stability and tendon strength include:
- Standing hamstring stretch – with the affected leg on a raised stool, keep it straight and lean forward (bending at the hips). Hold for 15-30 seconds, repeat 1 or 2 times
- Quad stretch – stand on one leg next to a wall and pull from the ankle of the injured leg towards your buttocks. There should be a stretch felt in the quadricep and knee muscles, hold for 15-20 seconds.
- Rectus femoris stretch – kneel the injured knee on an exercise pad, if there is pain immediately, then it is not yet ready to exercise. Place the other leg on the floor (foot flat). Then gently grab and pull the ankle on the injured side towards the buttocks. Hold for 10-20 seconds, repeat 3-4 times.
- Straight Leg Raise – lying on your back with legs straight, bend the uninjured knee with the foot flat on the floor. Lift the injured leg about 5-8 inches off the ground and slowly lower, tightening the muscles in the thigh and keeping the leg straight. Repeat 10-15 times
- Side-lying Leg Lift – lying with legs straight, sideways on the uninjured side, lift the injured leg away from the body. Do this slowly for 10-15 repetitions.
- Prone Hip Extension – lie face down on your stomach with legs straight. With the arms resting under the head, raise the affected leg slowly above the floor, hold for 5 seconds then lower. Do this for 10-15 repetitions.
- Clam Exercise – lay on the uninjured side with hips and knees bent and feet together. Slowly raise the injured leg toward the ceiling while keeping the heels touching each other. Hold for 2 seconds and lower slowly. Repeat 10-15 times
- Step-up – stand with the foot of the injured leg on a raised step or platform keeping the other foot on the floor. Shift your weight onto the injured leg on the support, straightening it as the other leg comes off the floor, repeat this for 15-20 repetitions.
- Wall Squat with a Ball – with your back against a wall place a medium sized exercise ball or even a football behind your back. Keeping the back straight, slowly squat to a 45-degree angle, hold this for 10 seconds and then slowly slide back up the wall. Repeat 15 times.
 Malliaras P, Cook J, Purdam C, Rio E. Patellar tendinopathy: clinical diagnosis, load management, and advice for challenging case presentations. Journal of Orthopaedic & Sports Physical Therapy. 2015; 45(11):887-898.  Lian ØB, Engebretsen L, Bahr R. Prevalence of jumper’s knee among elite athletes from different sports: a cross-sectional study. Am J Sports Med. 2005; 33:561-567.  Alexander RM. Energy-saving mechanisms in walking and running. J Exp Biol. 1991; 160:55-69.  Cook JL, Khan KM, Kiss ZS, Coleman BD, Griffiths L. Asymptomatic hypoechoic regions on patellar tendon ultrasound: a 4-year clinical and ultrasound followup of 46 tendons. Scand J Med Sci Sports. 2001; 11:321-327.  Malliaras P, Cook J, Ptasznik R, Thomas S. Prospective study of change in patellar tendon abnormality on imaging and pain over a volleyball season. Br J Sports Med. 2006; 40:272-274.  Ferretti A, Papandrea P, Conteduca F. Knee injuries in volleyball. Sports Med. 1990; 10: 132-138.
 Malliaras P, Cook J, Purdam C, Rio E. Patellar tendinopathy: clinical diagnosis, load management, and advice for challenging case presentations. Journal of Orthopaedic & Sports Physical Therapy. 2015; 45(11):887-898.
 Lian ØB, Engebretsen L, Bahr R. Prevalence of jumper’s knee among elite athletes from different sports: a cross-sectional study. Am J Sports Med. 2005; 33:561-567.
 Alexander RM. Energy-saving mechanisms in walking and running. J Exp Biol. 1991; 160:55-69.
 Cook JL, Khan KM, Kiss ZS, Coleman BD, Griffiths L. Asymptomatic hypoechoic regions on patellar tendon ultrasound: a 4-year clinical and ultrasound followup of 46 tendons. Scand J Med Sci Sports. 2001; 11:321-327.
 Malliaras P, Cook J, Ptasznik R, Thomas S. Prospective study of change in patellar tendon abnormality on imaging and pain over a volleyball season. Br J Sports Med. 2006; 40:272-274.
 Ferretti A, Papandrea P, Conteduca F. Knee injuries in volleyball. Sports Med. 1990; 10: 132-138.