Patellar Tendinopathy

Daniel B. Whelan, M.D., FRCSC
Toronto, ON

The patellar tendon is a relatively long tendon that acts through an indirect extended lever arm (with the patella as a fulcrum) to allow the quadriceps muscle to extend the leg.  It is relatively mechanically disadvantaged compared with other tendons. With repeated strain - as can occur in jumping sports such as basketball - micro-tears as well as collagen degeneration may occur in the tendon. The blood supply to the tendon is tenuous at its insertion to the patella and it is in this area that chronic patellar tendinopathy, or Jumper's Knee, can manifest (Figure 1).

 

WHELAN_FIG1

Figure 1: Saggital T2 MRI cut demonstrating common location of chronic patellar tendonopathy. Note the associated bone marrow edema, often postulated as an 'impingement' lesion in the pathogenesis of the disorder.

Many nonsurgical modalities have been described for the treatment of recalcitrant patellar tendinopathy. RCT's have demonstrated limited success (in terms of return to sport, pain relief, etc.) with eccentric exercise, injections, and ultrasound1-4. Surgery is usually reserved for recalcitrant cases. Prior to 2000, surgical series reported varying degrees of success (50 - 100%) with both open and arthroscopic approaches 5-10.

With the advent of the evidence-based movement, well conducted systematic reviews highlighted the huge variation in indications, techniques and effectiveness of surgical treatments10,11. One such study by Coleman et al (1999) evaluated the quality of evidence in support of surgery for patellar tendinopathy11. Not surprisingly, the published retrospective studies were all weak methodologically (Figure 2). Based on their findings, the investigators went so far as to question the benefit of surgery for the condition and established a list of methodological guidelines that would be essential for any future investigations to follow.

WHELAN_FIG2

Figure 2: Plot from the study of Coleman et al (1999) 13 demonstrating the (inverse) relationship between the adequacy of study methodology and reported surgical success.

The gauntlet laid down by Coleman et al was not challenged until recently. In 2006 a group of Norwegian investigators (Bahr et al) published a randomized trail comparing a regimen of eccentric training versus open surgery12. Using a validated disease specific outcome, surgery (either primary or secondarily after a failed course of therapy) was not found to be any more effective than the eccentric training protocol (Figure 3). Furthermore, both treatments gave relatively poor outcomes with only half of the patient's outcomes deemed 'successful'.

WHELAN_FIG3

Figure 3: From the randomized trial by Bahr et al. (2006) 14. Utilizing a validated, disease specific outcome measure, significant differences were not demonstrated between open surgical tendon debridement and eccentric muscle training.

Although many different surgeries have been described for patellar tendinopathy, there remains uncertainty as to their relative success given the poor methodology of predominantly respective studies. Furthermore, under the scrutiny of a randomized trial, surgery was not shown to impart any additional benefit over nonsurgical care. This trial was, admittedly, small and future investigations are required before definitive conclusions can be drawn. Nonetheless, the evolution of the surgical literature pertaining to Jumper's Knee does give one pause for caution in making firm recommendations based on low level evidence.

References

  1. Kongsgaard M., Kovanen V., Aagaard P., Doessing S., Hansen P., Laursen A.H., Kaldau N.C., Kjaer M., Magnusson S.P.  Corticosteroid injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy. Scand J Med Sci Sports 2009; 19:790-802
  2. Wang C.J., Ko J.Y., Chan Y.S., Weng L.H., Hsu S.L. Extracorporeal Shockwave for Chronic Patellar Tendinopathy. Am. J. Sports Med. 2007;35:972
  3. Hoksrud A., Ohberg L., Alfredson H., Bahr R.  ultrasound-Guided Sclerosis of Neovessels in Painful Chronic Patellar Tendinopathy: A Randomized Controlled Trial. Am J sports Med 2006;34:1738
  4. Frohm A., Saartok T., Halvorsen K., Renstrom P. Eccentric treatment for patellar tendinopathy: a prospective randomized short term pilot study of two rehabilitation protocols. Br J Sports Med. 2007 July; 41(7): e1 - e6.
  5. Griffiths G.P., Selesnick F.H. Operative treatment and arthroscopic findings in chronic patellar tendonitis. Arthroscopy. 1998;14:836-9
  6. Raatikainen T., Karpakka J., Puranen J., Orava S.  Operative treatment of partial rupture of the patellar ligament. A study of 138 cases.  Int J Sports med. 1994;15:46-9
  7. Karlsson J. et al.  Partial rupture of the patellar ligament. Results after operative treatment. Am J Sports med 1991;19(4):403-8
  8. Orava S., Osterback L., Hurme M.  Surgical treatment of patellar tendon pain in athletes. Br J Sports Med 1986;20(4):167-9
  9. Johnson D.P., Arthroscopic surgery for patellar tendonitis. Arthroscopy 1998;14(Suppl. 1):pS44
  10. Cucurulo T., Louis M.-L., Thaunat M., Franceschi J.P.  Surgical treatment of patellar tendinopathy in athletes.  A retrospective multicentric study. Orthopaedics & Traumatology:surgery & Research 2009;955:578-584
  11. Coleman B.D., Khan K.M., Kiss Z.S., Bartlett J., Young D.A., Wark J.D.  Open and arthroscopic patellar tenotomy for chronic patellar tendinopathy.  A retrospective outcome study.  Victorian Institute of Sport Tendon Study Group. Am J sports med. 2000;28:183-90
  12. Bahr R., Fossan B., Loken S., Engebretsen L.  Surgical Treatment Compared With Eccentric Training for Patellar Tendinopathy (Jumper's Knee). Journal Bone and Joint Surgery. 2006; 88:1689-98

 

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