Marc Darrow, M.D.
Over the years we have seen many people with varying degrees of knee problems. Among them, a diagnosis of “Jumper’s knee” or patellar tendinopathy. What is causing the knee pain and instability that these people complain of, are small tears in the patellar tendon. Most of these people have developed this knee problem as a result of playing sport or activity that requires a lot of jumping. Hence the name “jumper’s knee.”
Many people are basketball players, volleyball players, for the younger athlete track and field specialties such as triple jump, log jumps or high jumps may cause this problem. Distance runners are also prone because of the wear and tear involved in thousands of foot strikes to a road surface. Which brings us to the next point. Jumper’s knee or patellar tendinopathy, is not a problem of inflammation. It is a problem of degenerative war and tear. One aspect of patient characteristics that is being challenged is that this knee problem more impacts men than women.
Women make for a larger percentage of patellar tendinopathy than previous thought.
A June 2022 paper (1) questions this: “Patellar tendinopathy is one of the most common musculoskeletal problems associated with sport. While commonly perceived as a predominantly male problem, recent epidemiological studies revealed that it also affects a large number of sport-active women . . . Women represent only a minority of patients studied for this topic (this paper) showed a gender blindness in sports medicine when investigating a common problem like patellar tendinopathy.”
Physical therapy and exercise for Patellar tendinopathy
A May 2022 study (4) suggests that “Despite a dearth of studies on preventative interventions for athletes with Patellar tendinopathy, resistance training may be a useful prophylactic method. Eccentric, heavy slow and isometric resistance training have been found to be feasible and clinically beneficial in-season. There are a lack of studies showing that extracorporeal shock wave therapy offers any additional benefit over resistance training in competing athletes. Patellar strapping and taping may offer short-term pain relief during training and competition.”
Platelet-rich plasma injection in the treatment of patellar tendinopathy
A May 2022 paper (2) compared PRP injection with other ‘active treatment’ interventions (‘Non-PRP’ injection and ‘No-injection’ treatments) or ‘No-active treatment’ interventions. To do this the researchers examined eight published studies. They suggest “assessment of these studies revealed that there were no significant differences in pain relief, functional outcomes, and quality of life in the short, medium, and long term between PRP injection and Non-PRP injection interventions. Similarly, comparison of PRP injection to the No-active treatment intervention showed no differences in short- and medium-term pain relief. However, when PRP injection was compared to the No-injection treatment intervention extracorporeal shock wave therapy , the former was found to be more effective in terms of pain relief in the medium term and long term and functional outcomes in the medium term and long term. Conclusions: “In terms of pain relief and functional outcomes, the PRP injection did not provide significantly greater clinical benefit than Non-PRP injections in the treatment of patellar tendinopathy. However, in comparison with ESWT, there was a significant benefit in favor of PRP injection.”
Is PRP no better than a placebo? “IT’S UNCLEAR.”
One of the problems in understanding if PRP works for patellar tendinopathy is that empirically, doctors have seen good results. However, there is very little research to support this. In May 2022 a paper in The Journal of family practice (3) wrote:
Does platelet-rich plasma (PRP) injections improve patellar tendinopathy symptoms? “IT’S UNCLEAR. High-quality data have not consistently established the effectiveness of platelet-rich plasma (PRP) injections to improve symptomatic recovery in patellar tendinopathy, compared to placebo (strength of recommendation A), based on 3 small randomized controlled trials. The 3 small randomized controlled trials included only 111 patients, total. One found no evidence of significant improvement with PRP compared to controls. The other 2 studies showed mixed results, with different outcome measures favoring different treatment groups and heterogeneous results depending on follow-up duration.”
PRP is effective for patellar tendinopathy
However an April 2022 (5) also reviewed the previous research and said this: “Four studies investigated the efficacy of PRP injection on various outcome measures of patellar tendinopathy. All the selected studies reported a significant positive impact of PRP injection on patellar tendinopathy symptoms.” The researchers also noted “significantly improved” pain and functional scores at the 6- and 12-month follow-up assessments. Another study “reported that PRP accelerated the recovery compared to dry needling in a short-term follow-up. However, this benefit dissipated over time.” Further PRP showed better outcomes in short-term, medium-term, and long-term follow-ups compared to normal saline injection. The researchers here as well concluded there is not enough published research, stating: “However, because of the limited number of studies and the disparities in the study populations and protocols, it is not possible to make a firm conclusion on the efficacy of these injection methods, and these results should be inferred with care.”
UCLA doctors present a case history
Doctors at UCLA presented this September 2021 case history (6). It tells the story of a 19-year-old FEMALE Division-1 collegiate soccer player who came to the training room with a slowly developing and worsening onset right front knee pain. According to the case: “The pain started while she was doing rehabilitation following a right anterior cruciate ligament (ACL) reconstruction using a contralateral patellar tendon autograft. She has point tenderness over her right medial proximal patellar tendon, and she describes pain that worsens with repetitive loading of her knee during activities such as squats and running. She is diagnosed with patellar tendonitis via diagnostic ultrasound and starts physical therapy with a specific focus on eccentric and concentric loading of the quadriceps. She fails to improve following 3 months of compliant physical therapy and is frustrated by her continued pain. ” The patients was recommended to PRP injections. “Using ultrasound guidance, the athlete underwent a patellar tendon LP-PRP injection without the use of local anesthetic. She was restricted from lower body activities for 2 weeks to allow tissue recovery. She then resumed her rehabilitation program with a focus on eccentric loading in addition to her post-ACL reconstruction exercise regimen. At 15-month follow-up, she was ready to play in the season opener for her collegiate team.”
1 Mondini Trissino da Lodi C, Landini MP, Asunis E, Filardo G. Women Have Tendons… and Tendinopathy: Gender Bias is a “Gender Void” in Sports Medicine with a Lack of Women Data on Patellar Tendinopathy—A Systematic Review. Sports Medicine-Open. 2022 Dec;8(1):1-8.
2 Barman A, Sinha MK, Sahoo J, Jena D, Patel V, Patel S, Bhattacharjee S, Baral D. Platelet-rich plasma injection in the treatment of patellar tendinopathy: a systematic review and meta-analysis. Knee surgery & related research. 2022 Dec;34(1):1-5.
3 Wolfenden E, Vukelic B, DeMarco M, Knox J, Ose D. Does platelet-rich plasma improve patellar tendinopathy symptoms? J Fam Pract. 2022 May;71(4):188-189. doi: 10.12788/jfp.0402. PMID: 35730711.
4 Burton I. Interventions for prevention and in-season management of patellar tendinopathy in athletes: A scoping review. Physical Therapy in Sport. 2022 Mar 7.
5 Nuhmani S, Ahsan M, Bari MA, Malhotra D, Al Muslem WH, Alsaadi SM, Muaidi QI. Patellar Tendinopathy—Does Injection Therapy Have a Role? A Systematic Review of Randomised Control Trials. Journal of clinical medicine. 2022 Apr 3;11(7):2006.
6 Fahy KE, Miller EM, Kobayashi Y, Gottschalk AW. Efficacy of Platelet-Rich Plasma on Symptom Reduction in Patellar Tendinopathy. The Ochsner Journal. 2021;21(3):232.