Epidemiology Patellar tendinopathy (Jumpers knee)

Epidemiology Patellar tendinopathy (Jumpers knee)

Patellar tendinopathy (Jumpers knee) Patellar tendinopathy (jumper’s knee) is a condition usually associated with activities requiring repetitive forceful quadriceps contraction, and it is characterized by localized pain and tenderness of the patellar tendon at its origin on the inferior pole of the patella.16,17,18,19, 20, 21
Incidence Volleyball reports the highest prevalence rates where more than 40% of the male elite volleyball players report that they currently have or have had earlier complaints. Another study reported a prevalence of 34.5% among male elite junior volleyball players compared to 7.1% among the female elite volleyball players.13
Prevalence Chronic tendinopathy are common in both recreational and elite athletes. The prevalence of jumper’s knee is high in sports characterized by high demands on leg extensor speed and power, such as volleyball, basketball, soccer and athletics, where as many as 40-50% of participants are affected.’1,3,12
Sex Male > Female13
Age Most patients with jumper’s knee are between 20 and 40 years. It is almost exclusively occurs in intensive sportsmen,14 but the it may also affect patients with hyperparathyroidism.15
Etiology and pathogenesis The etiology and pathogenesis of chronic tendon pain is not fully understood, although histopathological and biochemical evidence indicates that it is not an inflammatory condition.5,6

The incomplete understanding of the underlying pathology limits our ability to establish effective treatment options. Surgery is advocated by some authors in recalcitrant cases,1,7,8 although the benefits of open tenotomy can be questioned on the basis of the result of a recent randomized, controlled study.9 Conservative treatment for patellar tendinopathy may include rest, use of anti‐inflammatory drugs, taping, massage, electrotherapy, ultrasound, laser therapy, extra‐corporeal shock wave therapy and other modalities.10, 11 However, non‐surgical treatment methods also need to be evaluated in well‐controlled clinical studies.

Histopathology Histopathologic changes associated with tendinopathy include degeneration and disorganization of collagen fibers, increased cellularity, and minimal inflammation.24,29 Macroscopic changes include tendon thickening, loss of mechanical properties, and pain.29 Recent work demonstrates several changes occur in response to overuse including the production of matrix metalloproteinases (MMPs), tendon cell apoptosis, chondroid metaplasia of the tendon, and expression of protective factors such as insulin-like growth factor 1 (IGF-1) and nitric oxide synthetase (NOS).22, 23, 25, 26, 27, 28, 30, 31
Risk factors Other risk factors which are associated with the disorder are: reduced strength of the calf, quadriceps, and buttock muscles, reduced trunk stability, reduced hamstring and quadriceps flexibility and excessive pronation of the foot. Also a reduced possibility of dorsiflexion in the ankle, for example after an ankle sprain, may play a role.13
Prognosis The symptoms are often serious, resulting in chronic impairment of athletic performance, and the condition can severely limit or even end an athletic career.1,4
  1. Cook J L, Khan K M, Harcourt P R. et al A cross sectional study of 100 athletes with jumper’s knee managed conservatively and surgically. The Victorian Institute of Sport Tendon Study Group. Br J Sports Med 1997. 31332-336.336.
  2. Adebajo AO, Nash P, Hazleman BL. A prospective double blind dummy placebo controlled study comparing triamcinolone hexacetonide injection with oral diclofenac 50 mg TDS in patients with rotator cuff tendinitis. J Rheumatol. 1990;17:1207-1210.
  3. Akgun K, Birtane M, Akarirmak U. Is local subacromial corticosteroid injection beneficial in subacromial impingement syndrome? Clin Rheumatol. 2004;23:496-500.
  4. Kettunen J A, Kvist M, Alanen E. et al Longterm prognosis for jumper’s knee in male athletes. A prospective followup study. Am J Sports Med 2002. 30689-692.692.
  5. Alfredson H. The chronic painful Achilles and patellar tendon: research on basic biology and treatment. Scand J Med Sci Sports 2005. 15252-259.259.
  6. Shalabi A, KristoffersenWiberg M, Aspelin P. et al Immediate Achilles tendon response after strength training evaluated by MRI. Med Sci Sports Exerc 2004. 361841-1846.1846.
  7. Kongsgaard M, Aagaard P, Roikjaer S. et al Decline eccentric squats increases patellar tendon loading compared to standard eccentric squats. Clin Biomech (Bristol, Avon) 2006. 21748-754.754.
  8. Popp J E, Yu J S, Kaeding C C. Recalcitrant patellar tendinitis. Magnetic resonance imaging, histologic evaluation, and surgical treatment. Am J Sports Med 1997. 25218-222.222.
  9. Bahr R, Fossan B, Loken S. et al Surgical treatment compared with eccentric training for patellar tendinopathy (Jumper’s knee). A randomized, controlled trial. J Bone Joint Surg Am 2006. 881689-1698.1698.
  10. Fredberg U, Bolvig L. Jumper’s knee. Review of the literature. Scand J Med Sci Sports 1999. 966-73.73.
  11. Peers K H, Lysens R J. Patellar tendinopathy in athletes: current diagnostic and therapeutic recommendations. Sports Med 2005. 3571-87.87.
  12. Philadelphia Panel evidence-based clinical practice guidelines on selected rehabilitation interventions for shoulder pain. Phys Ther.2001;81:1719-1730.
  13. Besseling RW, Biomechanical determinants of the jumper’s knee in volleyball [proefschrift]. Groningen: Rijksuniversiteit Groningen; 2008.
  14. Burgstein M. Zur Larsen-Johanssonschen Krankheit. Arch Orthop Unfall-Chir 1944; 43: 298-302
  15. Maddox PA, Garth WP. Tendinitis of the patellar ligament and quadriceps (jumper’s knee) as an initial presentation of hyperparathyroidism. J Bone Joint Surg (Am J Sports Med 1978; 6: 362-8
  16. Andres BM, Murrell GAC. Treatment of tendinopathy. Clin Orthop Relat Res. 2008;466:1539-1554.
  17. Ferretti A. Epidemiology of jumper’s knee. Sports Med. 1986;3:289-295.
  18. Ferretti A, Ippolito E, Mariani P, Puddu G. Jumper’s knee. Am J Sports Med. 1983;11:58-62.
  19. Peers KH, Lysens RJ. Patellar tendinopathy in athletes: current diagnostic and therapeutic recommendations. Sports Med. 2005;35:71-87.
  20. Rees JD, Maffuli N, Cook J. Management of tendinopathy. Am J Sports Med. 2009;37:1855-1867.
  21. Schmid MR, Hodler J, Cathrein P, Duewell S, Jacob HA, Romero J. Is impingement the cause of jumper’s knee? Dynamic and static magnetic resonance imaging of patellar tendinitis in an open-configuration system. Am J Sports Med. 2001;30:388-395.
  22. Archambault JM, Jelinsky SA, Lake SP, Hill AA, Glaser DL, Soslowsky LJ. Rat supraspinatus tendon expresses cartilage markers with overuse. J Orthop Res. 2007;25:617-624.
  23. Jones GC, Corps AN, Pennington CJ, Clark IM, Edwards DR, Bradley MM, Hazleman BL, Riley GP. Expression profiling of metalloproteinases and tissue inhibitors of metalloproteinases in normal and degenerate human achilles tendon. Arthritis Rheum. 2006;54:832-842.
  24. Khan KM, Cook JL, Bonar F, Harcourt P, Astrom M. Histopathology of common tendinopathies. Update and implications for clinical management. Sports Med. 1999;27:393-408.
  25. Lian O, Scott A, Engebretsen L, Bahr R, Duronio V, Khan K. Excessive apoptosis in patellar tendinopathy in athletes. Am J Sports Med. 2007;35:605-611.
  26. Longo UG, Franceschi F, Ruzzini L, Rabitti C, Morini S, Maffulli N, Forriol F, Denaro V. Light microscopic histology of supraspinatus tendon ruptures. Knee Surg Sports Traumatol Arthrosc. 2007;15:1390-1394.
  27. Scott A, Cook JL, Hart DA, Walker DC, Duronio V, Khan KM. Tenocyte responses to mechanical loading in vivo: a role for local insulin-like growth factor 1 signaling in early tendinosis in rats. Arthritis Rheum. 2007;56:871-881.
  28. Scott A, Khan KM, Duronio V. IGF-I activates PKB and prevents anoxic apoptosis in Achilles tendon cells. J Orthop Res. 2005;23:1219-1225.
  29. Soslowsky LJ, Thomopoulos S, Tun S, Flanagan CL, Keefer CC, Mastaw J, Carpenter JE. Neer Award 1999. Overuse activity injures the supraspinatus tendon in an animal model: a histologic and biomechanical study. J Shoulder Elbow Surg. 2000;9:79-84.
  30. Szomor ZL, Appleyard RC, Murrell GA. Overexpression of nitric oxide synthases in tendon overuse. J Orthop Res. 2006;24:80-86.
  31. Yuan J, Murrell GA, Wei AQ, Wang MX. Apoptosis in rotator cuff tendonopathy. J Orthop Res. 2002;20:1372-1379.


Physical Examination

Four phases of patellar tendinopathy1
The therapist asks about the cause and proces of the complaint and checks its clinical phenomena. These can be divided into the following phases:

Phase 1: Sport practitioner experiences pain or infrapatellar suprapatellar region after a workout or competition.

Phase 2: Sport practitioner experiences pain at the start of training which gradually disappears after warming up and reappears after finishing the training.

Phase 3: This phase is divided into:

– Sport practitioner experiencer pain during and after training, but they can participate at the same level, and;

– Sport practitioner experiences pain during and after training, but cannot participate at the same level.

Phase 4: Rarely occuring complete rupture of the tendon.

Single-leg decline squat:2
A function test described by Zwerver (2008) to heavily load the patellar tendon and provoke pain is called “single-leg decline squat”. There is no gold standard, but this test is sometimes used to support the diagnosis of patellar tendinopathy. Under an angle of 25 ° the athlete gradually drops a leg through.

Isolated isometric resistance test of the quadriceps:
To confirm the diagnosis, an isometric resistance test can be used to differentiate between the joint capsule and the joint of the muscle tendon unit. Because there is no movement in the joint while doing this test, recognizable pain is indicated on the tendon below the patella, it can be assumed that the problem is not in the capsular ligaments or joint.

VISA questionnaire3
To quantify the severity of the patellar tendinopathy you can use the ‘Victorian Institute of Sport Assessment (VISA)-score during the treatment process . The VISA questionnaire consists of eight questions that give an evaluation about the pain, function and the possibility of practicing sport. 100 points is an optimal healthy knee, to diagnose a patellar tendinopathy about 50 to 70 points is needed (Zwerver, 2008)1.

It is shown that the VISA score is a valid and reliable instrument for the diagnosis and to determine the prognosis in restoring the patellar tendon. The VISA score can determine the severity of the tendinopathy which can result in a rapid communication from therapist to the patient. Also, the VISA score has a quick test-retest which allows the progress of the patellar tendinopathy to be closely watched and a good intra-rater reliability both r = 0.95 (Visentini et. Al 1998).2

  1. Besseling RW, Biomechanical determinants of the jumper’s knee in volleyball [proefschrift]. Groningen: Rijksuniversiteit Groningen; 2008.
  2. Zwerver J. Patellatendinopathie (‘jumper’s knee’); een veelvoorkomende en lastig te behandelen sportblessure. Nederlands Tijdschrift voor Geneeskunde. 2008;152:1831-7.
  3. Visentini PJ, Khan KM, Cook JL, Kiss ZS, Harcourt PR, Wark JD. The VISA score: an index of serverity of symptoms in patients with jumper’s knee (patellar tendinosis). Journal of Science and Medicine in Sport 1998: Vol.1 (1): 22-28.


 Treatment for Patellar tendinopathy (Jumpers knee)

Eccentric training
According to Jonsson and Alfredson eccentric quadriceps training on a decline board gave a better result than concentric quadriceps training. At the 12‐week follow‐up, pain scores were significantly lower and VISA scores significantly higher in the eccentric training group compared with the concentric training group, and the patients were satisfied with treatment for 9 of 10 tendons. In the concentric group, pain levels remained high and no patient was satisfied with the result of the treatment.1

No study has made a direct comparison of the effect of slow eccentric training based on the Alfredson program.2

In a randomised trial on competitive volleyball players, Visnes et al3 used a similar treatment program to the decline groups in the studies by Purdam et al4 and Young et al.5

The main difference was that the athletes were allowed to train and compete as usual during the treatment period. Otherwise, the same principles with slow, painful decline squats were applied by the eccentric training group. The control group continued to train as normal. The results showed that there was no change in VISA score during the intervention period in the training or control group, nor was there any change during the follow‐up period at 6 weeks or 6 months. This indicates that it may not be possible to combine sports participation and eccentric exercises twice daily, and that the total load on the tendon was too high, resulting in increasing tendon soreness.

  1. Jonsson P, Alfredson H. Superior results with eccentric compared to concentric quadriceps training in patients with jumper’s knee: a prospective randomised study. Br J Sports Med 2005. 39847-850.850.
  2. Alfredson H, Pietila T, Jonsson P. et al Heavyload eccentric calf muscle training for the treatment of chronic Achilles tendinosis. Am J Sports Med 1998. 26360-366.366.
  3. Purdam C R, Jonsson P, Alfredson H. et al A pilot study of the eccentric decline squat in the management of painful chronic patellar tendinopathy. Br J Sports Med 2004. 38395–397.397.
  4. Young M A, Cook J L, Purdam C R. et al Eccentric decline squat protocol offers superior results at 12 months compared with traditional eccentric protocol for patellar tendinopathy in volleyball players. Br J Sports Med 2005. 39102-105.105.
  5. Visnes H, Hoksrud A, Cook J. et al No effect of eccentric training on jumper’s knee in volleyball players during the competitive season: a randomized clinical trial. Clin J Sport Med 2005. 15227-234.234.


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