Patellar tendinopathy

Patellar tendinopathy, often called “patellar tendinitis”, is a painful condition of the patellar tendon, most often located at its origin, at the inferior pole of the patella (kneecap). It is particularly common in sports involving repeated jumps, accelerations, decelerations, changes of direction, landings and explosive movements, which has earned it the nickname “Jumper’s knee”.

The term tendinopathy is now preferred to “tendinitis”. In chronic forms, the changes observed within the tendon correspond more to remodelling and alteration of the tendon structure (collagen disorganisation, changes in the extracellular matrix, cellular and vascular changes) than to simple inflammation. This is why purely anti-inflammatory treatments are not the core treatment: the main goal is to restore the mechanical capacity of the tendon.

The patellar tendon connects the patella to the tibial tuberosity. Together with the quadriceps, the patella and the quadriceps tendon, it forms the knee extensor mechanism. This tendon, which is usually a few centimetres long, is subjected to considerable stresses during explosive activities. Its proximal part, at the inferior pole of the patella, is the most common site of tendinopathy.

🔍 Click on the image to enlarge it

Function and biomechanics

The patellar tendon transmits the force generated by the quadriceps to the tibia (quadriceps → patella → patellar tendon → tibia). It thus enables knee extension, acceleration, jumping, landing, braking and changes of direction. It also acts as a structure capable of storing and then releasing elastic energy, a function that is particularly important in explosive movements.

During a jump, the force transmitted can be considerable; on landing, the tendon must absorb part of the mechanical energy before helping to release it during the next jump or acceleration. It is this capacity to store → release → repeat that explains why sports involving many jumps are particularly exposed to this condition.

Patellar tendinopathy is particularly common in jumping and pivoting sports: volleyball, basketball, handball, football, athletics. It can also affect runners, CrossFit athletes, weightlifters, people who do strength training and athletes who perform heavy squats.

A recent meta-analysis estimates its prevalence at around 18% in the athletic populations studied, with particularly high rates in jumping sports.

The tendon normally adapts to the stresses placed on it: when load increases gradually, its capacity increases accordingly (load → adaptation → increased tendon capacity). But if load increases too quickly relative to the tendon’s capacity to adapt, overload sets in and symptoms appear. This typically happens when there is a sudden increase in the number of jumps, intensity, training frequency, strength work, sprint volume or specific training.

Training-related factors

Sudden increase in training volume, increase in the number of jumps, return after a break, change of programme, increase in explosive sessions, sprint work or heavy squats.

Muscular factors

Quadriceps strength deficit, lower limb capacity deficit, muscle fatigue, posterior chain strength or endurance deficit.

Individual factors

Age, level of sport, history of tendinopathy, body composition, metabolic factors, certain medications. However, these individual factors should not be considered as sole causes.

The classic scenario

An athlete suddenly increases their training — for example, returning to basketball combined with more training sessions and extra jumping sessions. They then experience a typical progression: pain after training → pain during jumps → pain on stairs or when squatting. Gradually, the tendon becomes painful under lower and lower loads.

The pain is usually anterior, very localised and situated at the inferior pole of the patella: the patient often points precisely to the painful area with one finger, and this very precise location is characteristic. In some forms, the pain may also be felt lower down the tendon.

The mechanical nature of the pain is key: it appears during activities that place heavy demands on the extensor mechanism (jumping, landing, sprinting, squatting, lunging, climbing stairs, fast running) and may also be felt after training. In more advanced forms, pain may occur when walking, when squatting, or even at rest.

Jumping is particularly useful for assessing the tendinopathy (vertical jump, single-leg jump, horizontal jump, countermovement jump): the clinician looks for pain, loss of power, asymmetry or apprehension. Reduced jumping performance can be a useful functional indicator.

Clinical examination

On palpation, there is localised pain at the inferior pole of the patella, at the origin of the patellar tendon. On contraction, pain is sought during resisted extension, a squat or a jump. On stretching, deep knee flexion can reproduce the pain by putting the extensor mechanism under tension.

The squat test assesses pain, strength, knee control, tolerated depth and movement quality; the load can be increased gradually, as a deep squat considerably increases the load on the tendon. The single-leg decline squat is classically used in the assessment and monitoring of patellar tendinopathy: it reproduces the pain, assesses load tolerance and allows progress to be tracked, but it places a high load on the tendon and should therefore be used with caution in very irritable forms — recent biomechanical studies show that it is among the exercises that place the highest loads on the patellar tendon.

It is also useful to assess the strength of the quadriceps, hamstrings, triceps surae and hip muscles (dynamometer, isokinetic testing, functional tests, force platform), ideally comparing the painful side with the healthy side, and the current level with the athlete’s usual level.

Surgery is generally reserved for chronic, disabling forms that are resistant to well-conducted rehabilitation or associated with significant structural damage. It may involve debridement, excision of the pathological tissue or repair, using open or arthroscopic techniques.

A systematic review published in 2025 on surgery for refractory patellar tendinopathy reports a significant improvement in functional scores and an average return-to-sport rate of around 87%, while highlighting the considerable heterogeneity of the available studies and the lack of high-quality trials.

A patellar tendon rupture (in a healthy tendon after violent trauma, or in an already weakened tendon) is a different condition, causing sudden pain, a snapping sensation, loss of extension strength and difficulty lifting the straight leg: it is an orthopaedic emergency. A partial rupture can be more difficult to diagnose; treatment strategies are then very heterogeneous and depend in particular on the extent of the injury and the level of sport.

Improvement can be achieved within a few weeks, but full recovery often takes several months; chronic forms may require long, progressive rehabilitation. Return to sport should not be based solely on the number of weeks elapsed, but on several criteria: low, stable pain with no worsening the next day; satisfactory recovery of quadriceps strength with good symmetry and sufficient endurance; the ability to perform a single-leg squat, a lunge, a jump, a landing or changes of direction; and, depending on the sport, appropriate performance (jump height, power, speed, acceleration, repeated jumps).

The VISA-P (Victorian Institute of Sport Assessment – Patella) is a questionnaire specifically developed to assess the severity of patellar tendinopathy, covering pain, function and sporting capacity, with a score ranging from 0 (very poor functional status) to 100 (no significant limitation). It is particularly useful for tracking progress during rehabilitation.

After surgery, rehabilitation is progressive: protecting the repair and controlling oedema, then muscle recovery (quadriceps, hamstrings, hip, calf), strengthening (squats, leg press, single-leg work, progressive loads), impact work (jumps, landings, bounds) and finally return to sport (sprinting, changes of direction, sport-specific jumps, technical skills). The timeline depends heavily on the surgical procedure performed.

Prevention is mainly based on load progression, maintaining strength, sufficient recovery, varying intensities and monitoring symptoms. In jumping athletes, the capacity to absorb jumps must be trained as much as the capacity to jump: a sudden return to high plyometric volume after a period without jumping is indeed a classic overload scenario.