Evidence-Based Patellar Tendinopathy Rehab
Many athletes in running and jumping sports develop knee pain over the course of their career. When that pain is located in the tendon just below your patella (kneecap) it is commonly diagnosed as a patellar tendinopathy (see picture on the right for location of pain). Patellar tendinopathy is a common chronic tendon injury that is characterized by load-related pain in the patellar tendon. As many as 45% of elite athletes in jumping sports (i.e. basketball and volleyball) suffer from patellar tendinopathy. This can result in prolonged pain, disability and sport absence.
Most of the general population would refer to this as ‘tendinitis’. The suffix ‘itis’ refers to an ongoing inflammatory process. However, the histopathological studies confirm structural degenerative changes of the tendon tissue as the key feature, with minimal presence of inflammatory cells. Therefore, the term ‘tendinitis’ has been replaced by ‘tendinopathy’. For this reason, anti-inflammatory treatment options are discouraged and have proven to be ineffective for tendinopathy.
Eccentric exercises have strong evidence for effectively treating patellar tendinopathy, and have largely been the gold-standard for tendinopathy rehabilitation exercises. However, they are pain-provoking and the therapeutic effects on pain and functional outcomes are debated when it is applied during the competitive season. In a recent study published in the British Journal of Sports Medicine, Breda et al. studied the effectiveness of treating patellar tendinopathy using an alternate method called “Progressive Tendon Loading Exercises”. The new protocol had better outcomes than eccentric exercises after 24 weeks on the Victorian Institute of Sports Assessment for Patellar Tendons (a questionnaire measuring pain, function, and the ability to return to sports).
The Progressive Tendon Loading Exercises consist of 4 distinct stages that the athlete progresses through. The first stage consists of Daily Isometric Exercises. Isometric exercise involves a static contraction of the muscle without movement at the corresponding joints. It effectively creates load through the muscle, tendon and connective tissue without creating joint motion. Isometric exercises have also been shown to induce analgesia and decrease cortical inhibition. This is an important distinction from the eccentric exercise protocols which are known to temporarily increase pain. In this first stage the athlete performs single leg press or single leg extension exercises for 5 repetitions of 45 seconds, held at a mid-range (approximately 60° knee flexion) quadriceps isometric hold at 70% of the maximum voluntary contraction. The athlete can progress on to stage 2 once they can perform a single leg squat with a pain intensity of ≤ 3/10 and they have performed the stage 1 exercises for at least 1 week.
Stage 2 consists of different exercises on a two-day cycle. On day 1, the isometric exercises from Stage 1 are performed. On day 2, single leg press or single leg extension isotonic exercises are performed. The athlete begins at 4 sets of 15 repetitions between 10-60° of knee flexion and progresses to 4 sets of 6 repetitions with increasing load and knee angle (almost full extension to 90° flexion). After being able to complete a single leg squat with a pain intensity of ≤ 3/10 and performing Stage 2 for at least 1 week, athletes can progress to Stage 3.
Stage 3 is a three-day cycle involving plyometric and running exercises on every 3rd day. Day 1 and 2 will remain the same. The plyometric exercises (i.e. jump squats and box jumps) should be performed with 3 sets of 10 repetitions using both legs and slowly progressing to 6 sets of 10 repetitions using one leg. Once the athlete can perform a single leg squat and have completed the exercises in week 3 for at least one week they can progress to stage 4 (Sport-Specific Exercises).
The Stage 4 exercises will be dependent on the sport the athlete is competing in. However, they should only be performed every 2-3 days to allow for recovery from the high tendon load. The isometric exercises from Stage 1 should be performed on days that the sport-specific exercises are not being performed. When the athlete can perform all of the sport-specific exercises with a pain intensity of ≤ 3/10, they should return to competition. At that point stage 1 and 2 maintenance exercises are recommended 2x/week.
Patellar tendinopathy can be a stubborn injury to fully recovery from. It will undoubtedly require an active component to create load through the affected tendon. Please feel free to use the document below as a guide to structure your rehabilitation protocol. If you have any question feel free to contact me.
Breda SJ, Oei EHG, Zwerver J, et al. Effectiveness of progressive tendon-loading exercise therapy in patients with patellar tendinopathy: a randomised clinical trial. Br J Sports Med. 2020;0:1-9.
Rio E, Kidgell D, Purdam C, et al. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. Br J Sports Med. 2015;49:1277-1283.