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Patellar tendinopathy

77 citationsUpdated Oct 2026
Illustration: knee

For patients: a plain-language version of this topic is available. See the patient guide.

Overview

Patellar tendinopathy is an overuse condition of the knee extensor mechanism, most frequently affecting adolescents and young adults who participate in jumping sports [17]. The pathology localizes to the deep fibers of the patellar tendon attachment, where tenuous blood supply contributes to fibrinoid necrosis, mucoid degeneration, and disorganized collagen [17]. Clinical presentation involves insidious onset of pain and swelling that progresses from post-activity discomfort to functional limitation during activity [17]. Patients may report knee buckling due to reflex quadriceps inhibition [17]. While the term "patellar tendinopathy" is advocated for clinical use, specific histological diagnoses such as tendinosis or tendinitis require pathologist examination of tissue biopsies [2].

Nonoperative management remains the mainstay of treatment, initiated with activity modification followed by progressive eccentric strengthening and flexibility exercises [17]. Adjuncts include taping, infrapatellar straps, and NSAIDs, whereas corticosteroid injection is contraindicated due to the increased risk of tendon rupture [17]. Although platelet-rich plasma injections may offer clinical benefit in complex or refractory cases, current evidence quality is poor and results should be interpreted with caution [45, 46]. Ultrasound therapy is unlikely to be effective, and further high-quality studies are needed to evaluate loading programs and other modalities [8, 18].

Surgical intervention is reserved for chronic cases refractory to conservative care, offering substantial improvements in functional outcomes and high return-to-play rates [3, 12]. Arthroscopic surgery provides significant symptom relief comparable to open surgery, with improvements maintained for at least three years and a faster return to play [6, 118]. Procedures typically involve débridement of diseased tissue via longitudinal excision, bone abrasion or drilling to stimulate healing, and repair with sutures or anchors [17]. Advanced patellar tendinopathy is associated with increased bone-patellar tendon-bone autograft failure in ACL reconstructions, necessitating consideration of graft choice in these patients [34, 63].

Anatomy & Pathophysiology

Terminology and Definition

Patellar tendinopathy is characterized by activity-related anterior knee pain, focal patellar tendon tenderness, and intratendinous imaging changes [71]. Clinicians must clinically separate patellar tendinopathy from quadriceps tendinopathy to design more specific rehabilitation programs, as the two entities possess distinct anatomical, biomechanical, and epidemiological characteristics [25].

Etiology and Risk Factors

The pathogenesis of patellar tendinopathy involves both extrinsic and intrinsic factors. Extrinsic factors include patellar tendon loading, with mechanical overload in the extensor apparatus being the most frequently discussed cause [15]. Intrinsic factors include malalignment, patella alta, abnormal patellar laxity, muscular tightness, and imbalance [15]. The condition occurs in active individuals who engage in activities involving forceful, eccentric contraction of the knee extensor mechanism, particularly jumping sports [17]. Consequently, the prevalence of jumper's knee is high in sports characterized by high demands on speed and power for the leg extensors [129]. A greater incidence of patella alta, defined by sagittal patellar flexion angle measurement, was found to be clinically relevant in patellar tendinopathy patients, suggesting these individuals may comprise a recalcitrant subgroup who do not improve with current surgical intervention [9]. While the development of intratendinous alterations is associated with tendinopathy, predictive factors for these changes could not be identified [20].

Histopathology and Tissue Changes

The key pathophysiologic phenomenon of patellar tendinopathy is tendinosis, which refers specifically to the degenerative origin of the disease [15]. Tendinosis is characterized by progressive degeneration of the tendinous tissue, an inability of the tissue to repair itself, and the absence of inflammatory cells [15]. Macroscopically, the affected region of the patellar tendon appears yellow and is commonly described as "mucoid degeneration," contrasting with the normal bright, white, fibrous appearance of tendinous tissue [15]. Affected tissue may demonstrate fibrinoid necrosis, angiofibroblastic change, or mucoid degeneration and disorganized collagen structure [17]. Histologically, the condition is degenerative and noninflammatory, with a lack of neutrophils and macrophages, disorganized collagen, and increased vascularity [44]. Fibril morphology is abnormal in patellar tendinopathy, but tendon mechanical properties are not [130]. Underlying chronic degeneration in patellar tendon rupture is characterized by angiofibroblastic tendinosis, mucoid degeneration, and pseudocyst formation at the attachment of tendon to bone [27].

Biomechanics and Localization

Patellar tendinopathy usually affects athletes whose sport involves repetitive explosive extension or eccentric flexion of the knee [121]. The posterior region of the proximal patellar tendon is subjected to greater tendinous forces than is the corresponding anterior region [75]. Ultrasound examination of strained cadaveric patellar tendon complexes revealed disruption of fascicular architecture immediately adjacent to the inferior pole of the patella at the precise location of highest principal strain predicted by models [121]. Partial-thickness tears are located posterior or posteromedially in the proximal patellar tendon, with tendon thickness >8.8 mm strongly correlated with the presence of a tear [69]. Altered movement patterns during a drop jump may be perpetuating symptoms associated with patellar tendinopathy [14]. Tendon morphology is associated with symptom severity but not with functional impairments in patellar tendinopathy [11].

Imaging and Structural Findings

MRI usually shows thickening in the affected portion of the patellar tendon and may demonstrate intrasubstance signal abnormalities, but thickening is much more diagnostic than signal changes when identifying abnormal tendon [17]. About two thirds of patients with jumper's knee can be expected to have structural tendon changes with neovascularization [82]. Increased neovascularization in the tendon has been proposed to accompany the lack of reparative capacity and to be directly related to pain [15]. The presence of inflammatory mediators, in particular cyclooxygenase-2, has been linked to pain in patients with patellar tendinopathy in the absence of inflammatory cells [15]. Bilateral changes in tendon structure are observed in patients diagnosed with unilateral patellar tendinopathy, highlighting that the asymptomatic side should not be used as reference in clinical practice [136]. Although approximately 70% of tendons with structural changes at baseline were normal at 11-year follow-up, there was no clear relationship between structure and function [132].

Clinical Course and Prognosis

Patellar tendinopathy is a common condition with a prevalence of 14% in elite athletes depending on sport [71]. Disability associated with patellar tendinopathy is often prolonged and in many instances causes the premature cessation of an athletic career [71]. Clinical symptoms remained even years after loading-based treatment for patellar tendinopathy, whereas some but not all tendon structures normalized in longer term follow-up [4]. Jumper's knee causes mild but long-lasting symptoms after an athletic career [79].

Classification

Blazina: The Blazina classification defines stages of patellar or quadriceps tendinopathy based on pain presentation and functional limitation. Stage 1 is characterized by pain after activity [17]. Stage 2 involves pain during and after activity [17]. Stage 3 is defined by pain that limits function during an activity [17]. Alternative descriptions of this system outline four phases: Phase I is pain only after activity, Phase II is pain or discomfort during activity that does not interfere with sports participation, Phase III is pain both during and after participation that interferes with competition, and Phase IV is complete tendon disruption [112]. A third description grades the condition as Phase I for pain after activity only, Phase II for pain during and after activity, and Phase III for persistent pain with and without activity along with deterioration of performance [35].

Popkin-Golman (PG): The Popkin-Golman classification grades MRI findings of patellar tendinopathy. Grade 0 indicates a normal tendon or increased signal intensity of <25% of the axial cross-sectional width [74]. Grade 1 represents mild tendinopathy with increased signal intensity in 25% to 50% of the axial cross-sectional width [74]. Grade 2 denotes moderate tendinopathy with increased signal intensity >50% of the axial cross-sectional width [74]. Grade 3 signifies severe tendinopathy with partial patellar tendon tearing [74].

Clinical Presentation

History and Epidemiology

Patellar tendinopathy is characterized by tenderness on palpation and load-dependent pain at the inferior pole of the patella [58]. The condition occurs most frequently in adolescents and young adults [17], with males more commonly affected than females [35]. It affects active individuals who engage in activities involving forceful, eccentric contraction of the knee extensor mechanism, particularly jumping sports [17]. In a study of volleyball players, 51.0% were diagnosed with current patellar tendinopathy affecting at least one side [37]. The age at symptom onset in this cohort was 18.8±2.8 years (range, 13.5 to 25.9) [37], and the duration of symptoms was 3.5±2.4 years (range, 0.1 to 10) [37]. The onset of symptoms was gradual in 94% of knees [37]. Although mainly mild in nature, patellar tendinopathy is a fairly common condition in elite soccer with a high recurrence rate [39]. Player performance was not affected by the diagnosis, and athletes were able to return to play without any impact on career longevity [40].

Risk factors include poor quadriceps and hamstring flexibility [35]. MRI-defined patellar tendinopathy is common in community-based adults and is associated with current and past history of obesity assessed by BMI or body weight, but not fat mass [22]. Patients describe an insidious onset of pain and swelling of the affected tendon [17], often presenting with anterior knee pain at the inferior border of the patella [35]. In chronic cases, pain may be present at rest with prolonged sitting [35]. Clinical symptoms remained even years after loading-based treatment [4].

Physical Examination

Palpation will be painful at the insertion of the patella tendon to the inferior pole of the patella [35]. A Bassett sign is defined as tenderness to palpation at the distal pole of the patella in full extension, but no tenderness to palpation at the distal pole of the patella in full flexion [35]. Altered movement patterns may be perpetuating symptoms associated with patellar tendinopathy [14]. Physical test results including strength and flexibility in the lower limb, jump performance, and pain levels during pain-provoking tests were not identified as prognostic factors for patient-reported outcomes after exercise therapy [29].

Pathoanatomy and Classification

The area of patellar tendinopathy has a tenuous blood supply [17]. Affected tissue may demonstrate fibrinoid necrosis, angiofibroblastic change, or mucoid degeneration and disorganized collagen structure [17]. Tendinosis typically is located in the posterior portion of the proximal end of the patellar tendon adjacent to the inferior patellar pole [15]. Macroscopically, the affected region appears yellow and commonly is described as “mucoid degeneration” [15]. Neovascularisation is part of the pathophysiological process in tendinopathy of the Achilles tendon, patellar tendon, and upper extremity tendinopathies [43]. Chronic patellar tendon pain was found to be associated with high amounts of glutamate, but there were no signs of chemical inflammation (normal PGE2 levels) [111]. Chronic overload seems to be a major cause of patellar tendinitis [19], and mechanical overload in the extensor apparatus is discussed most frequently as an extrinsic factor [15].

Injuries can be graded according to the Blazina classification: * Phase I: Pain after activity only [35]. * Phase II: Pain during and after activity [35]. * Phase III: Persistent pain with and without activity along with deterioration of performance [35].

Imaging

Plain radiographs are often normal, but may show inferior traction spurs/enthesophyte in chronic cases [35]. MRI usually shows thickening in the affected portion of the tendon and also may demonstrate intrasubstance signal abnormalities [17]. Thickening is much more diagnostic than signal changes when identifying abnormal tendon on MRI [17]. MRI can show increased signal intensity on both T1 and T2 images and loss of the posterior border of the fat pad in chronic cases [35]. MRI may be useful to identify partial tears and chronic tears and may be used for surgical planning [35].

Ultrasonography will show thickening of the tendon and hypoechoic areas [35]. Ultrasonography was more accurate than MRI in confirming clinically diagnosed patellar tendinopathy [59]. Preseason ultrasound screening can identify symptomatic patellar tendinopathy and associated sequelae during the season, with preseason AP thickness serving as a more stable and precise measure of severity compared to VISA-P scores [61]. A greater patella alta incidence amongst patellar tendinopathy patients as defined by SPFA was found to be clinically relevant, as it suggests these patients may comprise the recalcitrant patient subgroup who do not improve with current surgical intervention and may therefore benefit from a biomechanical surgical solution [9].

Investigations

MRI: Magnetic resonance imaging is the primary modality for assessing structural integrity and grading pathology in patellar tendinopathy. Persistent patellar tendinopathy defined by MRI is associated with worsening knee pain in community-based middle-aged women [1]. Tendinopathic changes are identified by increased signal intensity in the patellar tendon on fat-suppressed proton density or T2-weighted sequences [74]. A standardized grading system classifies these findings based on the extent of signal alteration relative to the axial cross-sectional width of the tendon. Grade 0 represents normal tendon findings or increased signal intensity of <25% of the axial cross-sectional width [74]. Grade 1 indicates mild patellar tendinopathy with increased signal intensity in 25% to 50% of the axial cross-sectional width [74]. Grade 2 denotes moderate patellar tendinopathy with increased signal intensity >50% of the axial cross-sectional width [74]. Grade 3 signifies severe patellar tendinopathy with partial patellar tendon tearing [74].

Ultrasound: Color Doppler Ultrasound is utilized to detect structural tendon changes and neovascularization. Approximately two-thirds of patients with jumper's knee exhibit structural tendon changes with neovascularization on this modality [82]. Increased preseason patellar tendon thickness is associated with an increased risk of symptomatic patellar tendinopathy and associated sequelae in male NCAA Division I basketball players [134].

Other Considerations: Tendon morphology correlates with symptom severity but not with functional impairments in patients with patellar tendinopathy [11]. In adolescent elite athletes, the development of intratendinous alterations is associated with tendinopathy, although predictive factors could not be identified [20]. The relationship between the patella and the patellar tendon was identical in both groups studied; therefore, chronic overload seems to be a major cause of patellar tendinitis [19]. A greater patella alta incidence amongst patellar tendinopathy patients, as defined by sagittal patellar flexion angle (SPFA), is clinically relevant. This suggests these patients may comprise a recalcitrant subgroup who do not improve with current surgical intervention and may benefit from a biomechanical surgical solution [9]. The use of bone–patellar tendon–bone (BPTB) autograft is not recommended if patellar tendinopathy is obvious or there is suspicion of partial tendon tear on MRI [80].

Treatment

Non-Operative

Initial nonsurgical management consists of activity modification [17]. Taping to aid proprioception and patellar tracking, or the use of an infrapatellar strap, can be helpful in nonsurgical management [17]. Male gender and having fewer symptoms are possible predictors of effectiveness regarding the use of a patellar strap [28]. NSAIDs can be beneficial in the nonsurgical treatment of patellar tendinopathy [17], though treatment with corticosteroid injections and oral NSAIDs has shown positive short-term effects only [35]. Corticosteroid injection is contraindicated for patellar tendinopathy because of the increased risk of tendon rupture [17].

Extracorporeal shockwave therapy (ESWT) is an effective intervention that should be considered for patellar tendinopathy, particularly when other nonoperative treatments have failed [115]. ESWT appeared to be more effective and safer than traditional conservative treatments in the management of patients with chronic patellar tendinopathy [60]. However, ESWT as a solitary treatment during the competitive season has no benefit over placebo treatment in the management of actively competing jumping athletes with patellar tendinopathy who have symptoms for less than 12 months [110]. Sclerosing injections with polidocanol resulted in a significant improvement in knee function and reduced pain in patients with patellar tendinopathy [108]. Treatment with sclerosing injections targeting neovessels in patellar tendinosis has the potential to cure tendon pain and allow patients to return to full patellar-tendon loading activity [113].

Platelet-rich plasma (PRP) is a safe and promising therapy in the treatment of recalcitrant patellar tendinopathy [105]. Patellar tendons seem to benefit from PRP injections [117]. Treatment with PRP showed a significantly better outcome when used correctly for patellar tendinopathy [35]. Treatment with BM-MSC or Lp-PRP in combination with rehabilitation in chronic patellar tendinopathy is effective in reducing pain and improving activity levels in active participants [109]. The authors advocate for interpreting the results of the systematic review and meta-analysis with caution due to concerns regarding literature search, quality control, and publication bias, concluding that further research is needed to determine if PRP is a suitable nonsurgical alternative for patellar tendinopathy [46]. No recommendation can be made currently regarding prolotherapy injections using a local irritant to elicit an inflammatory healing response for patellar tendinopathy [17]. No recommendation can be made currently regarding platelet-rich plasma injection for patellar tendinopathy [17].

Treatment with shock waves and sclerotherapy have shown positive effects for patellar tendinopathy [35]. There was no evidence to support Kinesio taping, acupuncture, fascial therapy, or cryotherapy for patellar tendinopathy [35]. Ultrasound can likely be excluded as a treatment for patellar tendinopathy [18]. Although a small, immediate clinical response to IGF-1 injections was seen when combined with training, no additional long-term effect of intratendinous IGF-1 was observed on structural and clinical outcomes in patients with patellar tendinopathy [30]. There was no superior effect of exercising with a high load magnitude (HSR) compared with a moderate load magnitude (MSR) for the clinical outcome, tendon structure, or tendon function in the treatment of patellar tendinopathy in the short term [42]. Physical test results including strength and flexibility in the lower limb, jump performance, and pain levels during pain-provoking tests were not identified as prognostic factors for patient-reported outcomes after exercise therapy in patients with patellar tendinopathy [29]. In the group treated nonoperatively, results were better in the patients who had stage 2 tendinopathy than in those with stage 3 [65].

Operative

Indications: Surgery is reserved for patients who continue to have pain and swelling of the tendon after a nonsurgical treatment regimen has been attempted [17]. Arthroscopic treatment can relieve the pain of refractory chronic patellar tendinopathy [26].

Surgical Approach / Technique: Surgical procedures for patellar tendinopathy include various methods of débriding diseased tissue and stimulating a vigorous healing response [17]. There is no consensus in the literature on the best surgical procedure for patellar tendinosis when nonoperative treatment fails [124]. Studies that described surgical treatment of the inferior pole of the patella had 70.9% success compared to 91.7% for those that performed no patella bony work [124]. Closure of the paratenon was reported in seven studies with 84.8% success compared to 91.5% for the other studies [124].

Postoperative Rehabilitation: Postoperative rehabilitation for patellar tendinopathy surgery includes immobilization in extension, followed by progressive range of motion and strengthening [35]. The knee immobilizer is worn for 3 to 4 weeks, and crutches are used for partial weight bearing after chronic patellar tendinosis tenotomy and repair [116]. Stage 1 of rehabilitation after chronic patellar tendinosis tenotomy and repair should emphasize range of motion and isometric strengthening [116]. Closed-chain kinetics are started in stage 2 of rehabilitation after chronic patellar tendinosis tenotomy and repair when swelling and tenderness have resolved [116]. Stage 3 of rehabilitation after chronic patellar tendinosis tenotomy and repair should consist of activity-specific exercises, avoiding eccentric overload [116]. Return to full activities can be allowed when 85% to 90% of strength and full range of motion are achieved after chronic patellar tendinosis tenotomy and repair [116].

Outcomes: Return to activities is achieved by 80% to 90% of athletes after surgery for patellar tendinopathy [35]. There may be activity-related aching for 4 to 6 months after surgery for patellar tendinopathy [35]. Immobilization was used in four studies with 82.4% success compared to 94.9% success for four studies that did not immobilize postoperatively [124].

Complications

Surgical Complications and Outcomes

Chronic Rupture Repair: Repair of chronic patellar tendon rupture is complicated by proximal retraction of the patella and insufficient tissue for repair [27]. Similarly, chronic quadriceps tendon ruptures may present with proximal migration of the tendon stump, necessitating débridement and mobilization of the tendon [27]. The prognosis for quadriceps tendon ruptures is more guarded due to the incomplete nature of the injury and persistent degenerative tissue; outcomes are adversely affected by chondromalacia or patella alta [72]. Even when reconstruction of chronic patellar tendon rupture restores normal patellar height, function does not return to preinjury levels [77].

Revision Surgery for Tendinopathy: Open surgery involving excision of scarred tissue overlying the patellar tendon, separation of the patellar tendon from Hoffa body, multiple longitudinal tenotomies, and excision of macroscopically evident abnormal areas yields clinically relevant improvements in symptoms, VISA-P scores, and activity levels at 30-month follow-up [126]. In a cohort of athletes undergoing revision surgery for failed patellar tendinopathy treatment, 68.2% returned to competition within a year [126]. Male athletes returned to training slightly faster than female athletes (9.0 vs 10.0 months; P .04) [126]. The primary procedure being performed arthroscopically or in an open fashion did not have a statistically significant influence on the final result of the revision surgery [126].

Partial Tear Management: Patellar tendon reconstruction in addition to debridement in the setting of significant partial patellar tendon tearing provides patients with improved functional outcomes and decreases the risk for potential complications [10].

Autograft Selection: The use of bone-patellar tendon-bone autograft is not recommended if patellar tendinopathy is obvious or there are suspicions of partial tendon tear on MRI [80].

Non-Operative Complications

Injection and Steroid Risks: Corticosteroid injection is not recommended for patellar or quadriceps tendinopathy because it increases the risk of tendon rupture [38]. Anabolic steroid use and local corticosteroid injection into the tendon are associated with both patellar tendon and quadriceps tendon ruptures [27].

Recovery

Light activity (weeks): The evidence base does not specify a typical week range for desk work, driving, or light activities of daily living.

Full activity (months): The evidence base does not specify a typical month range for manual work, sport, or full range-of-motion and strength return.

Complete recovery / outcome plateau (months): The evidence base does not specify a typical month range for the stabilization of pain, strength, and final functional outcomes.

Rehabilitation protocol: Isometric exercise immediately reduces patellar tendon pain, with the analgesic effect sustained for at least 45 minutes [78].

Functional milestones: Arthroscopic surgery for patellar tendinopathy refractory to nonoperative management provides significant improvements in symptoms and function [6]. These improvements are maintained for at least 3 years [6]. Surgical treatment of refractory patellar tendinopathy leads to notable improvement in patient-reported outcomes [12] and high return-to-play rates [12]. Arthroscopic patellar release translates into sustained pain relief and functional improvement over a long-term follow-up in athletes [67]. Operative treatment gives good results in most cases of distal patellar tendinosis in athletes when conservative treatment has failed [33]. Both open and arthroscopic patellar tenotomy provided virtually all subjects with symptomatic benefit [48]. Patellar tendon reconstruction in addition to debridement in the setting of significant partial patellar tendon tearing provides patients with improved functional outcomes [10].

Other Considerations: Some but not all tendon structures normalized in longer term follow-up after loading-based treatment for patellar tendinopathy [4]. Fat pad debridement prolongs return-to-sport in surgical interventions for chronic patellar tendinopathy [3]. Only about half the subjects who underwent either open or arthroscopic patellar tenotomy were competing at their former sporting level at follow-up [48]. Patellar tendon reconstruction in addition to debridement in the setting of significant partial patellar tendon tearing decreases the risk for potential complications [10]. Quadriceps tendon ruptures have a more guarded prognosis due to incomplete nature and persistent degenerative tissue [72]. Results for quadriceps tendon ruptures are adversely affected by chondromalacia or patella alta [72]. Player performance was not affected by the diagnosis of patellar tendinopathy [40]. Athletes with patellar tendinopathy were able to return to play without any impact on career longevity [40].

Key Evidence

  • [L2] Persistent patellar tendinopathy is associated with worsening of knee pain. [1] (10.1186/s12891-015-0645-8)
  • [Paper] The term 'patellar tendinopathy' is advocated for clinical use to describe overuse conditions, while terms like tendinosis and tendinitis should only be applied following pathologist examination of tissue biopsies. [2] (10.1016/s0278-5919(03)00068-1)
  • [L1] Surgical treatment for chronic patellar tendinopathy leads to substantial improvements in functional outcomes. [3] (10.1002/ksa.70284)
  • [L4] Clinical symptoms remained even years after loading-based treatment for patellar tendinopathy, whereas some but not all tendon structures normalized in this longer term follow-up. [4] (10.1177/23259671241280192)
  • [L4] Arthroscopic surgery for patients with patellar tendinopathy refractory to nonoperative management appears to provide significant improvements in symptoms and function, with improvements maintained for at least 3 years. [6] (10.1177/0363546511410413)
  • [L3] Patients scheduled for surgery due to recalcitrant patellar tendinosis had longer patellar tendons compared to those without a history of patellar tendinosis. [7] (10.1177/2325967123s00268)
  • [L2] Good-quality studies comparing loading programmes and evaluating clinical and mechanistic outcomes are needed in both Achilles and patellar tendinopathy rehabilitation. [8] (10.1007/s40279-013-0019-z)
  • [L3] A greater patella alta incidence amongst patellar tendinopathy patients as defined by SPFA was found to be clinically relevant, as it suggests these patients may comprise the recalcitrant patient subgroup who do not improve with current surgical intervention and may therefore benefit from a biomechanical surgical solution. [9] (10.1007/s00167-020-06372-z)
  • [L5] Patellar tendon reconstruction in addition to debridement in the setting of significant partial patellar tendon tearing provides the patients with improved functional outcomes and decreases the risk for potential complications. [10] (10.1016/j.eats.2024.102931)
  • [L3] These findings suggest that tendon morphology is associated with symptom severity but not with functional impairments in patellar tendinopathy. [11] (10.1002/jor.25262)
  • [L4] Surgical treatment of refractory patellar tendinopathy leads to notable improvement in patient-reported outcomes and high return-to-play rates. [12] (10.5435/jaaosglobal-d-24-00146)
  • [L5] Treatment for patellar tendinopathy continues to evolve, with biologic and less-invasive ultrasound-based treatments showing promise, and surgical intervention providing reliable outcomes. [13] (10.1016/j.arthro.2023.09.004)
  • [L3] The altered movement patterns may be perpetuating symptoms associated with patellar tendinopathy. [14] (10.1177/2325967115576100)
  • [L5] [15] (10.5435/jaaos-d-15-00703)
  • [L2] Ultrasound can likely be excluded as a treatment for patellar tendinopathy, while other methods require further investigation. [18] (10.1007/s00167-011-1825-1)
  • [L3] The relationship between the patella and the patellar tendon was identical in both groups; therefore, chronic overload seems to be a major cause of patellar tendinitis. [19] (10.1177/03635465020300031401)
  • [L2] Development of intratendinous alterations in patellar tendons is associated with tendinopathy, but predictive factors could not be identified. [20] (10.1055/a-0633-9098)
  • [L1] The literature documents several nonsurgical approaches for the treatment of chronic patellar tendinopathy with important limitations in terms of study quality. [21] (10.1177/0363546518759674)
  • [L3] MRI defined patellar tendinopathy is common in community-based adults and is associated with current and past history of obesity assessed by BMI or body weight, but not fat mass. [22] (10.1186/1471-2474-15-266)
  • [L4] Minimally invasive arthroscopically assisted procedures have not reported better statistically significant results when compared to open surgery in the treatment of chronic proximal patellar tendinopathy. [24] (10.1007/s00167-012-2100-9)
  • [L5] Clinicians should clinically separate patellar tendinopathy and quadriceps tendinopathy to design more specific rehabilitation programs, as the two entities have distinct anatomical, biomechanical, and epidemiological characteristics. [25] (10.2519/jospt.2019.0611)
  • [L4] Arthroscopic treatment can relieve the pain of refractory chronic patellar tendinopathy. [26] (10.1007/s11999-011-1886-y)
  • [L3] Male gender and having fewer symptoms were possible predictors of effectiveness in patellar tendinopathy patients. [28] (10.1016/j.jsams.2015.04.016)
  • [L3] In patients with patellar tendinopathy, physical test results including strength and flexibility in the lower limb, jump performance, and pain levels during pain-provoking tests were not identified as prognostic factors for patient-reported outcomes after exercise therapy. [29] (10.1177/03635465231200241)
  • [L1] Although a small, immediate clinical response to IGF-1 injections was seen when combined with training, no additional long-term effect of intratendinous IGF-1 was observed on structural and clinical outcomes in patients with patellar tendinopathy. [30] (10.1177/03635465211021056)
  • [L4] Operative treatment seems to give good results in most cases of distal patellar tendinosis in athletes when conservative treatment has failed. [33] (10.1007/s00167-006-0135-5)
  • [L3] Consideration of patellar tendinopathy should be made when determining the optimal graft choice for patients undergoing primary ACL reconstruction with autograft tendons. [34] (10.1177/2325967118s00142)
  • [L3] [37] (10.1177/03635465030310031401)
  • [L2] Although mainly mild in nature, patellar tendinopathy is a fairly common condition in elite soccer and the recurrence rate is high. [39] (10.1177/0363546511408877)
  • [L3] Player performance was not affected by the diagnosis of patellar tendinopathy, and athletes were able to RTP without any impact on career longevity. [40] (10.1177/23259671211025305)
  • [L1] There was no superior effect of exercising with a high load magnitude (HSR) compared with a moderate load magnitude (MSR) for the clinical outcome, tendon structure, or tendon function in the treatment of patellar tendinopathy in the short term. [42] (10.1177/0363546520988741)
  • [L4] Neovascularisation is part of the pathophysiological process in tendinopathy of the Achilles tendon, patellar tendon, and upper extremity tendinopathies. [43] (10.1186/1749-799x-3-18)
  • [L1] [44] (10.1177/0363546510387095)
  • [L1] PRP injections offer a clinical benefit and may be considered a suitable option to treat chronic patellar tendinopathy, particularly for complex cases or when nonsurgical rehabilitative approaches have failed, although the evidence is not definitive due to the generally poor quality of current literature. [45] (10.1177/0363546518788320)
  • [L5] The authors advocate for interpreting the results of the systematic review and meta-analysis with caution due to concerns regarding literature search, quality control, and publication bias, concluding that further research is needed to determine if platelet-rich plasma is a suitable nonsurgical alternative for patellar tendinopathy. [46] (10.1177/0363546518788315)
  • [L3] Both procedures provided virtually all subjects with symptomatic benefit, but only about half the subjects who underwent either open or arthroscopic patellar tenotomy were competing at their former sporting level at follow-up. [48] (10.1177/03635465000280020801)
  • [L5] [58] (10.1002/ksa.12367)
  • [L2] Ultrasonography was more accurate than MRI in confirming clinically diagnosed patellar tendinopathy. [59] (10.1177/0363546506294858)
  • [L2] Extracorporeal shockwave therapy appeared to be more effective and safer than traditional conservative treatments in the management of patients with chronic patellar tendinopathy. [60] (10.1177/0363546506298109)
  • [L2] Preseason ultrasound screening can identify symptomatic patellar tendinopathy and associated sequelae during the season, with preseason AP thickness serving as a more stable and precise measure of severity compared to VISA-P scores. [61] (10.1177/2325967123s00252)
  • [L3] Patellar tendinopathy should be considered when determining the optimal graft choice for patients undergoing primary ACL reconstruction with autograft tendons. [63] (10.1177/2325967118807710)
  • [L3] In the group treated nonoperatively, results were better in the patients who had stage 2 tendinopathy than in those with stage 3. [65] (10.1177/03635465000280031901)
  • [L4] Arthroscopic patellar release translates into sustained pain relief and functional improvement over a long-term follow-up in athletes. [67] (10.1186/s12891-017-1851-3)
  • [L2] Partial-thickness tears are located posterior or posteromedially in the proximal patellar tendon, with tendon thickness >8.8 mm strongly correlated with the presence of a tear. [69] (10.1177/0363546519894333)
  • [L4] [71] (10.1002/jor.20415)
  • [L4] Quadriceps tendon ruptures have a more guarded prognosis due to incomplete nature and persistent degenerative tissue, with results adversely affected by chondromalacia or patella alta. [72] (10.1177/036354658401200508)
  • [L3] [74] (10.5435/jaaos-d-24-01217)
  • [L5] The posterior region of the proximal patellar tendon is subjected to greater tendinous forces than is the corresponding anterior region. [75] (10.1177/0363546508319311)
  • [L4] However, despite the restoration of a normal patellar height, function did not return to preinjury level. [77] (10.1007/s00167-015-3951-7)
  • [L1] Isometric exercise immediately reduced patellar tendon pain with the effect sustained for at least 45 min. [78] (10.1136/bjsports-2014-094386)
  • [L3] Jumper's knee causes mild but long-lasting symptoms after an athletic career. [79] (10.1177/03635465020300051001)
  • [L3] The use of BPTB autograft is not recommended if patellar tendinopathy is obvious or there are suspicious of partial tendon tear on MRI. [80] (10.1007/s00167-018-5066-4)
  • [L3] About two thirds of patients with jumper's knee can be expected to have structural tendon changes with neovascularization. [82] (10.1177/0363546508319897)
  • [L2] Platelet-rich plasma is a safe and promising therapy in the treatment of recalcitrant patellar tendinopathy. [105] (10.1177/0363546514560726)
  • [L1] Sclerosing injections with polidocanol resulted in a significant improvement in knee function and reduced pain in patients with patellar tendinopathy. [108] (10.1177/0363546506289168)
  • [L2] Treatment with BM-MSC or Lp-PRP in combination with rehabilitation in chronic patellar tendinopathy is effective in reducing pain and improving activity levels in active participants. [109] (10.1177/0363546521998725)
  • [L1] Extracorporeal shockwave therapy as a solitary treatment during the competitive season has no benefit over placebo treatment in the management of actively competing jumping athletes with patellar tendinopathy who have symptoms for less than 12 months. [110] (10.1177/0363546510395492)
  • [L4] Chronic patellar tendon pain (Jumper's knee/tendinosis) was found to be associated with high amounts of glutamate, but there were no signs of chemical inflammation (normal PGE2 levels). [111] (10.1016/s0736-0266(01)00016-x)
  • [Paper] [112] (10.1016/j.eats.2016.10.025)
  • [L4] Treatment with sclerosing injections targeting neovessels in patellar tendinosis has the potential to cure tendon pain and allow patients to return to full patellar-tendon loading activity. [113] (10.1007/s00167-004-0549-x)
  • [L2] Extracorporeal shock wave therapy is an effective intervention and should be considered for greater trochanteric pain syndrome, patellar tendinopathy, and Achilles tendinopathy particularly when other nonoperative treatments have failed. [115] (10.1177/0363546514531911)
  • [L4] Patellar tendons seem to benefit from PRP injections, whereas in the Achilles tendon, PRP application is not indicated neither as a conservative approach nor as a surgical augmentation. [117] (10.1007/s00167-016-4261-4)
  • [L5] Arthroscopic surgery is as effective as open surgery for patellar tendonitis, with a faster return to play when surgery is indicated. [118] (10.1016/j.arthro.2015.09.006)
  • [Paper] The described surgical technique is an easy, effective, and inexpensive option with high reproducibility for treating chronic proximal patellar tendinopathy, allowing for a safe return to sports activities without the need for surgical implants. [120] (10.1016/j.eats.2019.07.013)
  • [L5] [121] (10.1177/0363546508322496)
  • [L4] [124] (10.1097/blo.0b013e318030841c)
  • [L4] [126] (10.1177/2325967121994550)
  • [L4] The prevalence of jumper's knee is high in sports characterized by high demands on speed and power for the leg extensors. [129] (10.1177/0363546504270454)
  • [L2] Fibril morphology is abnormal in tendinopathy, but tendon mechanical properties are not. [130] (10.1177/0363546509350915)
  • [L2] Although approximately 70% of tendons with structural changes at baseline were normal at follow-up, there was no clear relationship between structure and function. [132] (10.1177/03635465241284648)
  • [L2] Increased preseason patellar tendon thickness is associated with an increased risk of symptomatic patellar tendinopathy and associated sequelae in male NCAA Division I basketball players. [134] (10.2106/jbjs.24.00680)
  • [L3] These results stress the importance of monitoring both symptomatic and asymptomatic tendon structures and in addition highlight that the asymptomatic side should not be used as reference in clinical practice. [136] (10.1007/s00167-019-05495-2)

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b. TO THE EXTENT POSSIBLE, IN NO EVENT WILL THE LICENSOR BE LIABLE TO YOU ON ANY LEGAL THEORY (INCLUDING, WITHOUT LIMITATION, NEGLIGENCE) OR OTHERWISE FOR ANY DIRECT, SPECIAL, INDIRECT, INCIDENTAL, CONSEQUENTIAL, PUNITIVE, EXEMPLARY, OR OTHER LOSSES, COSTS, EXPENSES, OR DAMAGES ARISING OUT OF THIS PUBLIC LICENSE OR USE OF THE LICENSED MATERIAL, EVEN IF THE LICENSOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH LOSSES, COSTS, EXPENSES, OR DAMAGES. WHERE A LIMITATION OF LIABILITY IS NOT ALLOWED IN FULL OR IN PART, THIS LIMITATION MAY NOT APPLY TO YOU.

c. The disclaimer of warranties and limitation of liability provided above shall be interpreted in a manner that, to the extent possible, most closely approximates an absolute disclaimer and waiver of all liability.

Section 6 -- Term and Termination.

a. This Public License applies for the term of the Copyright and Similar Rights licensed here. However, if You fail to comply with this Public License, then Your rights under this Public License terminate automatically.

b. Where Your right to use the Licensed Material has terminated under Section 6(a), it reinstates:

1. automatically as of the date the violation is cured, provided it is cured within 30 days of Your discovery of the violation; or

2. upon express reinstatement by the Licensor.

For the avoidance of doubt, this Section 6(b) does not affect any right the Licensor may have to seek remedies for Your violations of this Public License.

c. For the avoidance of doubt, the Licensor may also offer the Licensed Material under separate terms or conditions or stop distributing the Licensed Material at any time; however, doing so will not terminate this Public License.

d. Sections 1, 5, 6, 7, and 8 survive termination of this Public License.

Section 7 -- Other Terms and Conditions.

a. The Licensor shall not be bound by any additional or different terms or conditions communicated by You unless expressly agreed.

b. Any arrangements, understandings, or agreements regarding the Licensed Material not stated herein are separate from and independent of the terms and conditions of this Public License.

Section 8 -- Interpretation.

a. For the avoidance of doubt, this Public License does not, and shall not be interpreted to, reduce, limit, restrict, or impose conditions on any use of the Licensed Material that could lawfully be made without permission under this Public License.

b. To the extent possible, if any provision of this Public License is deemed unenforceable, it shall be automatically reformed to the minimum extent necessary to make it enforceable. If the provision cannot be reformed, it shall be severed from this Public License without affecting the enforceability of the remaining terms and conditions.

c. No term or condition of this Public License will be waived and no failure to comply consented to unless expressly agreed to by the Licensor.

d. Nothing in this Public License constitutes or may be interpreted as a limitation upon, or waiver of, any privileges and immunities that apply to the Licensor or You, including from the legal processes of any jurisdiction or authority.

Creative Commons is not a party to its public licenses. Notwithstanding, Creative Commons may elect to apply one of its public licenses to material it publishes and in those instances will be considered the “Licensor.” The text of the Creative Commons public licenses is dedicated to the public domain under the CC0 Public Domain Dedication. Except for the limited purpose of indicating that material is shared under a Creative Commons public license or as otherwise permitted by the Creative Commons policies published at creativecommons.org/policies, Creative Commons does not authorize the use of the trademark "Creative Commons" or any other trademark or logo of Creative Commons without its prior written consent including, without limitation, in connection with any unauthorized modifications to any of its public licenses or any other arrangements, understandings, or agreements concerning use of licensed material. For the avoidance of doubt, this paragraph does not form part of the public licenses.

Creative Commons may be contacted at creativecommons.org.