Progressive tendon loading may achieve greater improvements in pain, function and ability to play sports than eccentric exercise
Progressive tendon loading may be a good option if eccentric exercise is too pain-provoking
After progressive tendon loading more patients report an “excellent satisfaction”
Eccentric exercises for patellar tendinopathy (PT) have received strong recommendations but may be pain-provoking. The authors therefore evaluated the effectiveness of progressive tendon-loading in patellar tendinopathy (PTLE), which have been proposed in the management of PT earlier on, compared to eccentric exercise therapy (EET) as recommended by several guidelines.
A prospectively registered RCT was designed to compare PTLE and EET in recreational, competitive and professional athletes with PT aged 18-35. PT had to be associated with training and competition. Diagnosis of PT was based on pain provocation on palpation or during single-leg squat, and confirmed by abnormalities on ultrasound and Doppler. Patients were allocated to receive either PTLE or EET.
Patients were instructed to perform progressive loading exercises based on pain response in four different stages of rehabilitation.
Progressions through the stages were based on pain provocation during the single-leg squat. If pain during this test was in the acceptable range (VAS ≤ 3/10) and the exercises of the stage had been performed for at least one week, the next stage could be commenced.
Progression to stage 2 was allowed if there was complete adherence to stage 1 and when pain during eccentric exercises with additional weights was acceptable (VAS ≤ 3/10). Return to sport (RTS) was allowed after 4 weeks and when pain during a single-leg squat was acceptable (VAS ≤ 3/10).
Both groups received additional exercises targeting PT risk factors. The additional exercises were flexibility exercises of hamstrings, quadriceps, gastrocnemius and soleus, strength exercises for hip abductors and extensors using resistance bands, calf strengthening exercises and core stability. Advice and education was given to both groups explaining PT, the expected management, the positive influence of exercise and the importance of gradual RTS. The relationship between load and pain was also explained. Patients in both groups were advised to modify their athletic activities when pain-provoking. A substantial reduction of the activity or a complete stop for at least 4 weeks were recommended. Performing activities within the limits of acceptable pain was advised.
At 24 weeks, but not at 12 weeks, a significant difference was found favoring PTLE. Sensitivity analyses revealed consistent results, except when missing results were replaced by the worst outcome of the treatment group. Both groups had equal numbers of patients achieving the minimal clinically important difference (MCID).
No significant difference in RTS rate between PTLE and EET was found. Patients in both the PTLE and EET groups reached similar levels of patient satisfaction at 12 and 24 weeks. However, the PTLE group had a significantly higher percentage of patients with satisfaction reaching “excellent” (38% vs 10%). RTS and satisfaction were not influenced by symptom duration. No between group difference was found for patient satisfaction at 12 or 24 weeks. At 24 weeks, pain in the PTLE group was significantly lower (2/10 vs 4/10 in the EET group).
Several strengths can be noted. This investigator-blinded RCT was a priori registered which is good since this way protocol deviations are unlikely. A thorough screening for PT was performed prior to inclusion of subjects into the study. The allocation was concealed for the main investigator and sports-physician, so they were unbiased in their assessment. The authors made a distinction between acute and chronic PT by stratifying the randomisation based on early or longstanding PT. Adjustment for baseline variables were predefined. Good results for both programs were found notwithstanding the fact that they were unsupervised.
As with all research, this study shows some limitations. First of all pain was significantly lower after PTLE, but this difference is not clinically relevant, since a reduction of at least 3 points on the VAS scale is proposed to be an important change. The ultrasound evaluation of the patellar tendon was performed, however it was unclear whether findings were compared bilaterally. Overall low adherence rates were observed in both groups, suggesting an unsupervised program may not be suitable for every subject. It would have been interesting to see a subanalysis comparing the most adherent subjects in both groups.
Some precautions should be taken into consideration. The return to sports was low: at 24 weeks less than half of subjects returned to sports at their preinjury level and an equal percentage of patients in both groups reached the MCID, suggesting there is still room for improvement (for example with a supervised program). The authors indicated that when adjusting for missing values in the best case and most likely scenario the PTLE was superior regarding the primary outcome. However this was not true when the worst case scenario (which replaced the missing value in the PTLE group with the worst value observed in this group) was analysed. Therefore the result favoring the PTLE group for the VISA-P score may not be fully trustworthy. A large spread for the outcome was observed so not every subject had the same benefit from the exercise programs, indicating the importance of an individualized treatment approach.
PTLE may be a good option if EET is too pain-provoking in young recreational, competitive and professional athletes with PT. This PTLE may achieve greater improvements in pain, function and ability to play sports (as measured by the VISA-P) than the EET. The PTLE group reached equal improvements in RTS rate, patient satisfaction and pain compared to the EET program. After PTLE more patients report an “excellent satisfaction” score. There may be room for improvement when the PTLE program is performed in a supervised environment.
Breda SJ, Oei EHG, et al. Effectiveness of progressive tendon-loading exercise therapy in patients with patellar tendinopathy: a randomised clinical trial. Br J Sports Med. 2021 May;55(9):501-509. doi: 10.1136/bjsports-2020-103403. https://pubmed.ncbi.nlm.nih.gov/33219115/