INTRODUCTION — Overuse tendinopathy is a clinical syndrome characterized by chronic pain and tendon thickening. It commonly results from overuse and occurs in workers and athletes from recreational to elite. The majority of tendinopathies present in the chronic stage, with symptoms over three months in duration.
Normally, tendon consists of tightly packed collagen fibers. In tendinopathies, the collagen matrix is in a state of disrepair, with proliferation of collagen and proteoglycans and angioblastic hyperplasia (disordered tissue repair with vascular and fibroblastic components) in the tendon and its linings (paratendon and endotendon). This pattern is similar in most tendinopathies of the upper and lower extremity. Although complete or partial tendon ruptures may result from overuse, their treatment principles differ markedly from overuse tendinopathies and are therefore discussed separately. Paratendinopathies (eg, de Quervain tenosynovitis) are also distinct in that the primary pathology is the paratendon rather than the tendon proper and are not discussed here.
The general management of chronic tendinopathy is discussed here. The pathophysiology of tendinopathy, the use of biologic therapies, and the management of specific tendinopathies are reviewed separately:
●Pathophysiology of tendinopathy and biologic therapies (See "Overview of overuse (persistent) tendinopathy" and "Biologic therapies for tendon and muscle injury".)
●Upper extremity tendinopathies (See "Rotator cuff tendinopathy" and "Calcific tendinopathy of the shoulder" and "Biceps tendinopathy and tendon rupture" and "Elbow tendinopathy (tennis and golf elbow)" and "de Quervain tendinopathy".)
●Lower extremity tendinopathies (See "Achilles tendinopathy and tendon rupture" and "Non-Achilles ankle tendinopathy" and "Calf injuries not involving the Achilles tendon" and "Quadriceps muscle and tendon injuries" and "Overview of running injuries of the lower extremity".)
PATIENT HISTORY AND ASSESSMENT — The patient's history should elucidate what type of training or activity led to the tendinopathy and clarify the level of function to which the patient aims to return. Most often, the patient has substantially increased the volume or intensity of their activity, producing a rapid increase in the tensile or compressive loading of the tendon, or has returned to their previous exercise or activity level too quickly after a significant period of unloading (eg, holiday, injury). The history may also provide clues to alternative diagnoses, such as gout, fluoroquinolone toxicity, seronegative arthropathies, systemic lupus erythematosus, or tendon xanthoma.
Validated, reliable, and simple functional assessment scores, such as the Victoria Institute of Sport Assessment (VISA) for patellar tendinopathy or VISA-A for Achilles tendinopathy, can help the clinician to grade symptoms and determine patient function (figure 1 and figure 2) [1,2]. Such scores also provide a useful means of monitoring longer-term recovery during rehabilitation. The VISA and VISA-A questionnaires can be completed in five minutes or less and have been translated into many languages.
APPROACH TO TREATMENT — Tendinopathies are chronic injuries that are slow to resolve, often requiring months for complete resolution. Patience and careful adherence to an active rehabilitation program emphasizing heavy-load exercise and a return to full activity implemented in progressive steps are the keys to successful treatment. An algorithm summarizing our approach to treatment is provided (algorithm 1). (See 'Heavy-load resistance training' below.)
Clinicians should take adequate time to explain to patients that a prolonged recovery (often three to six months) is likely and that they should not be discouraged by ongoing symptoms during rehabilitation. Indeed, symptoms often worsen during the initial stages of exercise therapy as loads placed on the tendon increase, but this does not necessarily mean the tendon injury is being aggravated. Educating patients about the benefits of mechanical load in stimulating tissue repair is important to successful treatment [3].
Maintaining a realistic view of rehabilitation is essential to patient engagement and treatment success. With challenging cases, careful oversight by a physiotherapist or exercise specialist is important to ensure that loads are heavy enough to promote tendon adaptation [4] but not so heavy as to exacerbate injury, impair function, cause excessive pain, or demoralize the patient.
The treatment steps outlined immediately below are based upon the algorithm developed for Achilles tendinopathy [5]. The exact steps may vary depending upon clinical circumstance, but the principles of controlled, progressive tendon loading and gradual resumption of activity remain central to any program. Time frames are approximate.
●Assess patient with mid-tendon pain: evaluate structures and joints that function in concert with involved tendon (ie, kinetic chain); examine peritendinous structures; rule out complete or partial tendon rupture.
●If tendinopathy is the leading diagnosis, reduce or modify activities that provoke tendon pain and, guided by symptoms, begin a controlled exercise program using progressively heavier loads under appropriate supervision (6 to 12 weeks); a short course of oral or topical analgesics may be helpful early in treatment. (See 'Antiinflammatory medications' below and 'Topical nitroglycerin (glyceryl trinitrate)' below.)
●If patient improves, continue exercise program (6 to 12 months) and gradually introduce higher tendon-loading activities (running, jumping, and throwing activities as relevant to the tendinopathy and patient goals).
●If no improvement, modify exercise program (adjust tendon load); reassess the kinetic chain and technique, volume, and intensity of provocative activities, such as running or jumping, making modifications as indicated; may trial adjunct therapies (eg, topical nitroglycerin [TNG]; 6 to 12 weeks).
●If still no improvement after modifications in exercise program, reassess diagnosis or possible contribution of systemic comorbidities, altered biomechanics, and loading parameters; modify exercise program; continue TNG; and add adjunct therapies (eg, tissue mobilization, extracorporeal shock wave therapy; 6 to 12 weeks).
●If still no improvement, continue exercise program, consider other pain-reducing adjunct treatments; depending upon clinician comfort and experience and available resources, may add investigational treatments or opt for rheumatologic or surgical referral as appropriate (4 to 6 weeks).
TREATMENTS — A variety of approaches have been advocated for the treatment of tendinopathy. The most common and well-supported strategies are presented here. Less well-established and investigational approaches are discussed below. An algorithm summarizing our approach to treatment is provided (algorithm 1). (See 'Unproven and investigational treatments' below.)
Of note, the medical literature describes a number of differences among tendon types and specific tendons such that caution is warranted before generalizing treatment effects across conditions. Reported differences include sensitization of the central nervous system in upper limb but less with lower limb tendinopathies [6,7], variable function in energy storage and postural control [8], and unique anatomic and biomechanical features of specific tendons. Such differences may explain in part why clinical studies seldom identify a universal effect for a given intervention across all tendinopathies.
The success of conservative treatment frequently depends upon a coordinated program of education, relative rest, including a reduction of aggravating activities, correction of any underlying biomechanical faults, active rehabilitation, and then a gradual increase in tendon-loading activities.
Activity modification and tendon load — For patients who engage in activities that place high loads on tendons (eg, sports involving sprinting and jumping) or that involve prolonged lower-intensity loads, particularly on tendons of the upper extremities, it is important that coaches and employers be aware of activity modifications in the treatment plan. Activity modification requires limiting the volume and intensity of loads placed upon the injured tendon for a designated period to allow for symptoms to resolve.
Normally, fluid within the extracellular matrix enables tendons to absorb force, making them more resistant to strain [9-11]. However, with sustained repetitive loading, fluid is displaced (or "wrung out") from the tendon, reducing its capacity to absorb force, thereby increasing susceptibility to injury. In addition, loading of a fatigued tendon (so-called "fatigue loading") induces a "loosening" of the tightly packed collagen-proteoglycan matrix, without evidence of collagen tearing [12,13]. As a result, a load that was historically manageable can subsequently produce tendon damage with excessive repetition. To minimize further matrix changes, increases in training load or functional activity should be gradual.
It is important to recognize the contribution of training (ie, loading) errors to the development of tendinopathy and the role of appropriate loading during treatment [14]. Rapid increases in training volume, intensity, and/or frequency are well-recognized factors in the development of tendinopathy, while others (eg, a low level of tissue loading at baseline) may also play a role [15,16]. Establishing a moderate-to-high chronic training load is protective against tendon injury, while chronic underloading is thought to increase susceptibility [15,16]. The onset of tendinopathy frequently occurs during rapid reloading after a period of deloading (eg, return to intense training following a holiday, illness, or another injury). Consistently maintaining moderate, repetitive loads is necessary for tendons to retain resilience. Rehabilitation essentially seeks to rebuild tolerance for higher volumes of tendon loading through a graduated progression of resistance training [17]. Depending on patient activities and aspirations, the ultimate goal is to tolerate high rates of loading, as occur during sprinting, jumping, or throwing. The key to successful rehabilitation of tendon injury appears to be determining the optimal load for exercises as well as the desired rate of progression of the load.
Biomechanical modification — In general, the biomechanics of major tasks possibly contributing to the tendinopathy should be analyzed and optimized by an ergonomics specialist, a trained physiotherapist or kinesiologist, a knowledgeable sports medicine clinician, or a comparable expert. This approach has not been studied in large, randomized trials but is supported by clinical experience and biomechanical modeling.
Studies have found mixed associations between abnormal biomechanics or specific performance characteristics and the development of tendinopathy [18-22]. As an example, computer users in one study were randomly assigned to use four different keyboard types [23]. A reduction in tendon and other musculoskeletal complaints occurred after several months in patients using an ergonomic keyboard. In another small, prospective cohort study of auto workers, epicondyle tendinopathy was strongly associated with the amount of time spent with the wrist out of neutral position during work [22]. A systematic review of prospective and cohort studies concluded that specific biomechanical faults (eg, increased eversion range of motion of the rearfoot or increased duration of the gait cycle spent in rearfoot eversion) during running may predispose to Achilles tendinopathy, and that biomechanical assessment of running may be helpful in making treatment decisions for those with an overuse tendinopathy stemming from running [24,25]. As another example, cohort studies have found that limited ankle dorsiflexion is associated with patellar tendinopathy [26-28]. (See "Clinical assessment of walking and running gait".)
Heavy-load resistance training — Controlled, progressive resistance training using relatively heavy loads should serve as the cornerstone of treatment for most cases of chronic tendinopathy, including Achilles, patellar, and lateral elbow tendinopathy. This approach is supported by the results of nearly all studies of tendinopathy management where a well-designed, resistance exercise program was considered the primary intervention.
Specific instructions for implementing a resistance exercise program for the treatment of tendinopathy are beyond the scope of this review. The performance of specific rehabilitative exercise programs in the management of Achilles tendinopathy, patellar tendinopathy, and lateral epicondyle tendinopathy are discussed in the topics devoted to those injuries, as are the rehabilitation of common musculoskeletal injuries of the knee and shoulder; our fundamental approach to the management of tendinopathy is described above. (See "Achilles tendinopathy and tendon rupture" and "Quadriceps muscle and tendon injuries" and "Elbow tendinopathy (tennis and golf elbow)" and "Rehabilitation of common knee injuries and conditions" and "Rehabilitation principles and practice for shoulder impingement and related problems" and 'Approach to treatment' above.)
There are several types of resistance exercise. Eccentric exercise involves the application of a load to a lengthening muscle; concentric exercise is the application of a load to a shortening (or contracting) muscle; isometric exercise is the maintenance of tension within a muscle held in a static position (neither lengthening nor shortening). Studies of tendinopathy treatment have generally focused on exercises that emphasize eccentric movement or a combination of eccentric and concentric movement. No approach (eg, eccentric-focused) has demonstrated greater effectiveness.
The strain from exercising with progressively heavier tensile loads, moved in a slow, controlled manner, stimulates tissue remodeling. This process is termed mechanotransduction [3]. Such exercise may be uncomfortable when initially performed, but done properly, it should not cause severe pain or result in any worsening of symptoms (eg, pain or joint swelling the next day). During rehabilitative exercise, discomfort should be kept within moderate levels that do not reflect further injury [29]. The type and amount of loading prescribed should be tailored to the patient, taking into consideration their injury, pain and fatigability, and the level of function ultimately required (based on vocational or sporting demands). Progression (ie, increases in load or volume) should be gradual and carefully monitored.
Regardless of the tendon involved, it is important that a knowledgeable therapist supervise the patient beginning a rehabilitation regimen involving heavy-load resistance exercise. Such supervision is most important for the rehabilitation of lower limb tendons as the loads placed on these tendons frequently reach multiples of body weight during athletic activity. The therapist must ensure that exercise technique is biomechanically sound, and the intensity and frequency of the program are appropriate to the patient and clinical circumstance [30]. As an example, for rotator cuff tendinopathy, an exercise program that addresses not only the injured muscle-tendon unit (eg, supraspinatus) but also the coordination and function of the scapulothoracic and scapulohumeral joints should be prescribed [31]. In addition, the therapist should be able to supervise a graduated transition from the heavy, slow muscle-tendon loading program emphasized early during rehabilitation to the higher rate of loading required later during rehabilitation as an athlete prepares for return to full sport. If this progression is too rapid, symptoms frequently recur.
Several randomized and observational studies, performed primarily in patients with midportion Achilles tendinopathy, have found unilateral, eccentric exercise performed in a controlled manner using heavy loads to be an effective treatment for overuse tendinopathy [29,32-38]. The results of subsequent studies suggest that bilateral exercise involving both eccentric and concentric movements performed in a similar fashion (ie, controlled movement using heavy loads) may be equally effective [39-42]. Two meta-analyses were unable to determine the superiority of one exercise type over another for Achilles tendinopathy [43,44] or in both Achilles and patellar tendinopathy [41]. A systematic review of studies of patellar tendinopathy found that loaded isometric exercise may be useful for pain control, whereas heavy resistance exercise, whether bilateral using eccentric and concentric movements or unilateral emphasizing eccentric movement, produces more sustained pain reduction and improved function [45].
Studies of treatment for tendinopathy of the upper limb report similar results for such an exercise-based approach. A systematic review of eight studies of lateral elbow tendinopathy found statistically significant short-term improvements in pain and function for patients treated with eccentric strengthening exercises, although long-term results were inconclusive [46]. A systematic review of ten studies of low to moderate quality that assessed exercise treatment for shoulder tendinopathy reported greater improvements in function compared with placebo or no treatment [47]. Another review found no conclusive evidence supporting the superiority of any particular exercise program (eg, eccentric versus eccentric plus concentric) for the condition [48]. In a randomized trial involving 100 patients that compared high-versus low-load strength exercises for rotator cuff tendinopathy, no significant differences between groups were noted in pain, range of motion, or strength at 12 weeks [49].
Antiinflammatory medications — The majority of tendinopathies demonstrate minimal or no cellular inflammation [50]. However, there may be a low level of biochemical inflammation present that contributes to pain and which can be reduced with antiinflammatory medications, particularly during the early phases of tendinopathy [51]. This may in part explain why glucocorticoid injection is effective for the short-term relief of pain but not for long-term healing.
Nonsteroidal antiinflammatory drugs (NSAIDs) — Oral NSAIDs (and acetaminophen) may be helpful for short-term (eg, five to seven days) pain relief. In addition, NSAIDs may reduce tenocyte motility and activity [52], which may be useful during early phases of tendinopathy. Given the absence of prominent inflammation in most cases of tendinopathy and the known systemic side effects associated with chronic use, we prefer to avoid long-term NSAID use in the treatment of tendinopathy. (See "Nonselective NSAIDs: Overview of adverse effects".)
Multiple controlled trials support the effectiveness of topical NSAID gel or iontophoresis for short-term pain control [53-57]. Topical NSAIDs may cause fewer systemic side effects than oral NSAIDs and systematic reviews have found no difference in long-term treatment outcomes [56,58]. Should patients require ongoing treatment with high doses of analgesics despite optimal conservative management, the clinician should consider alternative diagnoses, such as significant tendon tear or inflammatory arthropathy.
Glucocorticoids — The effectiveness and risks associated with glucocorticoid treatment of tendinopathy appear to vary with the duration of symptoms and the mode of drug delivery (eg, local injection versus systemic treatment). For ongoing treatment of chronic tendinopathy, glucocorticoids are potentially harmful and we suggest they be avoided [59]. Glucocorticoids inhibit tendon adaptations to load [60] and collagen synthesis, possibly increasing the risk of tendon rupture, more so in the lower limb [61]. In patients with chronic symptoms of patellar or Achilles tendinopathy, glucocorticoid injections have not proven effective [39,62]. A systematic review concluded that subacromial injections are effective at reducing symptoms, but the patients included suffered from a variety of pathologies (eg, adhesive capsulitis, labral injuries) so it is difficult to draw meaningful conclusions [63]. According to another systematic review, glucocorticoid injections for lateral epicondyle tendinopathy reduce pain initially but ultimately increase recurrence rates and lead to inferior long-term outcomes [58,64]. A subsequent systematic review of randomized trials involving glucocorticoid injections for patients with lateral epicondyle tendinopathy or tendinopathy of the rotator cuff or Achilles tendon reported similar findings [65].
Local glucocorticoid therapy may be useful for treating symptoms in patients with acute tendinopathy. Judicious use of local glucocorticoid injection to reduce pain and improve function acutely can be a reasonable part of a comprehensive treatment plan. Multiple trials report reductions in acute pain from local glucocorticoid injection [59,63,65,66]. Glucocorticoid may also be administered via iontophoresis. As examples, in a small randomized trial, glucocorticoids delivered by iontophoresis improved pain and stiffness in patients with Achilles tendinopathy of less than three months duration [67], while a similar trial found that iontophoresis with glucocorticoid and lidocaine improved pain and function in patients with lateral elbow tendinopathy [68]. When considering glucocorticoid injection for patellar and lateral elbow tendinopathy, clinicians must balance short-term pain reduction with the increased risk of worse long-term outcomes [39,65]. (See "Elbow tendinopathy (tennis and golf elbow)", section on 'Secondary management'.)
Topical nitroglycerin (glyceryl trinitrate) — Nitroglycerin (also referred to as glyceryl trinitrate) patches are placed directly over affected tendons to deliver nitric oxide, a potent signaling molecule that stimulates collagen synthesis in tendon cells, among its many effects. The dose used in most trials has been either one-fourth or one-half of a 5 mg/24 hour or 10 mg/24 hour patch left on continuously for 24 hours. Evidence primarily drawn from two small randomized trials performed by the same research group in people with chronic tendon pain, one for the Achilles [69] and one for the rotator cuff [70], supports the use of topical nitroglycerin (TNG). Given its low cost, relative safety, and limited evidence of benefit for a condition that is not easy to treat, TNG may be a reasonable adjunct therapy for patients being managed with physical therapy or if other conservative measures have failed. Additional high-quality studies are needed to determine the effectiveness of TNG.
Nitric oxide therapy should be used in conjunction with an active rehabilitation regime emphasizing heavy resistance exercise, and patients should be advised that it may take 12 to 24 weeks to experience significant improvement. When using TNG, the skin should be monitored for signs of irritation and the patient should be made aware that dizziness and headaches are potential side effects. Contraindications include patients with hypotension, migraine headaches, rosacea, head injury, severe anemia, and those taking any other source of nitrates (eg, nitroglycerin, phosphodiesterase inhibitors such as sildenafil). Overall nitric oxide therapy is safe; the dropout rate averages approximately 18 percent (generally headache and skin rash) [71].
Evidence supporting the use of TNG remains preliminary, and the results of future studies are likely to influence the decision to use TNG. A 2018 systematic review and meta-analysis [71] identified 10 randomized controlled trials of TNG of variable quality, of which two were not placebo controlled [72,73]. Among the most notable findings in the meta-analysis were the increase in satisfaction rates and in the number who became asymptomatic with activities of daily living among patients in the treatment group [71]. The review concluded that "randomized controlled trials in all tendinopathies reveal improved midterm (up to six months) improvements in pain, strength, and patient satisfaction." Pain at rest was unaffected. However, in spite of positive overall findings, the results of the individual studies showed limitations in clinical benefit. Examples include the following:
●In the only controlled trial for patellar tendinopathy, 33 patients were randomized to TNG or placebo and no differences between groups were found in pain reduction, condition severity, or patient satisfaction over a 24-week period [74].
●In a placebo-controlled trial for Achilles tendinopathy, 65 patients were randomized and significant reductions in activity-related pain were observed with TNG compared with placebo at 12 and 24 weeks (mean difference <1 point on a four-point scale) [69].
●A randomized placebo-controlled trial of 154 adult patients with chronic lateral elbow tendinopathy found that "in the short term, there is little therapeutic effect of continuous topical nitroglycerin treatment, at any dosage, in chronic lateral epicondylosis when combined with a daily stretching programme" [75]. This study was discontinued at eight weeks, and resistance exercise was not included among the interventions.
Shock wave therapy — The use of extracorporeal shock wave therapy (ESWT) as an adjunct for treating chronic soft tissue injury is evolving, although study results continue to be mixed. We believe it is reasonable to use ESWT in cases of chronic tendinopathy that are not improving adequately with a high-load resistance exercise program. Many trials of ESWT have been limited by inconsistent treatment protocols, small sample size, and other methodologic issues. Future controlled trials of ESWT should focus on specific tendon (and fascial) injuries and use newer methods and consistent protocols for shock wave administration to assess whether this treatment improves patient-important clinical outcomes.
A number of early clinical trials examined the efficacy of ESWT in tendinopathy and found marginal improvements over placebo [76-79]. These trials involved a range of treatment protocols. Subsequent systematic reviews have reached mixed conclusions about the effectiveness of ESWT for treating tendinopathy. Two reviews concluded that there is insufficient evidence to recommend shock wave therapy for lateral elbow tendinopathy or noncalcific rotator cuff tendinopathy [58,80], while a 2011 review concluded there was insufficient evidence to recommend ESWT for the treatment of midportion Achilles tendinopathy [81]. In addition, a few small, limited, randomized trials investigating the combination of exercise therapy and ESWT in the treatment of rotator cuff and patellar tendinopathy have found no added benefit from ESWT [82-84].
Other trials have reported positive results. A 2015 systematic review concluded that there is moderate evidence for the effectiveness of ESWT for the treatment of three lower limb tendinopathies: greater trochanteric pain syndrome, patellar tendinopathy, and Achilles tendinopathy [85]. Research included in this review of lower limb tendinopathies consisted primarily of case-control studies and lower-quality, controlled trials. A subsequent meta-analysis limited to randomized trials (n=29) with a minimum PEDro quality score of six assessed the use of ESWT for lower limb tendinopathies and reported a pooled reduction in pain (standardized mean difference -1.41; 95% CI -2.01 to -0.82) and improvement in function (standardized mean difference 2.59; 95% CI 1.54 to 3.64) immediately following treatment [86]. These improvements were retained at 3 months, 6 months, and beyond 12 months. Of note, not all studies were limited to tendinopathy; medial tibial stress syndrome, Osgood-Schlatter, Achilles bursitis, and iliotibial band syndrome were included in some. The meta-analysis found that focused, high dose (HD) ESWT was more effective than radial, HD ESWT. Another meta-analysis of moderate-quality evidence found that radial ESWT was more effective than conservative treatment in the management of proximal hamstring tendinopathy [87].
UNPROVEN AND INVESTIGATIONAL TREATMENTS — A number of therapies for chronic tendinopathy, even some that are used relatively often, lack supporting evidence and may be the subject of ongoing research. These therapies include the following:
Joint mobilization and friction massage — Although there is little evidence to support their use across the board, certain manual techniques specific to an anatomic location may serve as a useful adjunct to active rehabilitation. Clinical experience suggests that joint or muscle dysfunction may contribute to altered muscle activation and movement patterns, and abnormal tendon loading. This dysfunction may be amenable to treatment with manual therapy techniques performed by an appropriately trained therapist.
In one randomized trial, patients with chronic tendinopathy of the lateral epicondyle were randomly assigned to receive physiotherapy including joint mobilization (mobilization with movement [MWM]), corticosteroid injections, or a wait-and-see approach [88]. Patients in the MWM group recovered more quickly than those in the wait-and-see group and had significantly better long-term outcomes than the corticosteroid group. Several case studies also support the use of MWM for other upper extremity tendinopathies [89].
Historically, friction massage applied directly to the painful tendon (the Cyriax approach) was considered an important treatment for tendinopathy [90]. Animal studies demonstrate that friction massage can increase tendon fibroblast activity [91]. However, a systematic review concluded that friction massage combined with other physiotherapy modalities (not including therapeutic exercise) does not consistently improve pain, grip strength, or functional status in tendinopathy patients [92]. This is in line with our clinical experience and subsequent clinical trials, which show minimal benefit from friction massage compared with exercise therapy [93,94].
Ice or heat — Neither ice nor heat are important treatments after the acute phase of injury but may serve as useful adjuncts for reducing symptoms in some patients during ongoing treatment of chronic tendinopathy. Controversy surrounding the use of ice or heat to treat chronic tendinopathy stems from historical debates about the role of inflammation in the condition. One small study found that ice provided no benefit when added to a program of eccentric exercise to treat lateral epicondyle tendinopathy [95]. Conversely, one small randomized trial found that heat (delivered by microwave diathermy) led to improved patient satisfaction with treatment [96]. Heat may be useful for treating muscle spasm associated with tendinopathy.
Stretching — The most effective means of increasing a muscle's optimum length (reflecting the addition of sarcomeres in series within the myotendinous unit) appears to be through the remodeling that occurs in response to heavy-load eccentric exercise performed through a full, functional range of motion [97,98]. However, stretching may be used as an adjunct treatment for tendinopathy patients, both for symptomatic relief of muscle spasm and for lengthening functionally shortened muscle-tendon units. (See 'Heavy-load resistance training' above.)
Larger tendons, like the Achilles, may be stretched manually by a therapist if peritendinous adhesions (a rare occurrence) are suspected of limiting tendon movement. However, emphasis should be on the patient regularly performing stretching as part of a comprehensive rehabilitation program. These exercises should incorporate a steady hold to maximize muscle lengthening. Of note, stretching of insertional tendinopathy (eg, Achilles enthesopathy) may exacerbate the condition due to entheseal compression. Partial tears of a tendon can also be exacerbated by stretching.
Stretching has long been advocated to prevent tendinopathy. However, a systematic review found insufficient evidence to support or refute the use of stretching to treat or prevent Achilles tendinopathy [99]. Another systematic review found no clear evidence that stretching prevents sports-related injury [100].
Despite the absence of definitive studies, many sports clinicians and physiotherapists routinely include stretching in their programs for the prevention and treatment of tendinopathies. If stretching is prescribed, we suggest the following guidelines:
●Perform stretching exercises following activity, when muscles are warm; stretching before activity does not prevent injury and may cause transient decreases in strength [100,101]. Before activity, perform a gradual active warm-up that involves the major muscles to be used. Stretching of warm muscles induces greater gains in flexibility than stretching without warming [102].
●Stretch regularly (three to five days per week); flexibility gains from a single stretching session last 90 minutes, but gains from regular regimens persist for weeks after cessation [103].
Alternatives to static stretching, such as proprioceptive neuromuscular facilitation (which incorporates brief periods of muscular contraction during stretching) and dynamic stretching (which involves active movement of the joint), may be beneficial, but studies are limited and further research is needed. Supervised forms of yoga or similar approaches, performed over months or years, may improve general or specific flexibility in a more strategic and controlled manner. Hatha yoga has been shown to produce improvements in mobility equivalent to dynamic stretching [104].
Prolotherapy — Prolotherapy involves the injection of a substance, usually dextrose and lidocaine, intratendinously or at the enthesis, with the intent of stimulating a repair response. While several small trials noted below report positive results, additional, well-performed randomized trials are needed to assess this treatment before it can be recommended. Prolotherapy is associated with few side effects [105].
One small randomized trial in patients with chronic epicondylalgia found that prolotherapy provided significant pain relief and improvement in grip strength 16 weeks after the initiation of treatment [106]. A small, single-blind randomized trial in patients with chronic Achilles tendinopathy found greater improvement in the Victoria Institute of Sport Assessment for Achilles tendinopathy (VISA-A) score at 6 weeks and 12 months with prolotherapy plus eccentric exercise compared with eccentric exercise alone [107]. Another small, double-blind randomized trial found that a greater percentage of patients with chronic rotator cuff tendinopathy experienced significant pain relief after receiving dextrose-lidocaine (16 out of 27) compared with patients receiving a superficial injection of saline (7 out of 26) [108]. There was no difference in sonographic appearance between the groups [109,110]. A meta-analysis of 18 heterogeneous trials found that prolotherapy was better than other injectables for long-term (>24 weeks) relief of pain and improvement in function for rotator cuff tendinopathy [66].
Sclerotherapy — Chronic tendinopathy is associated with neovascularization of affected tendons. Injections of a sclerosing substance (eg, polidocanol) to reduce neovascularity have shown promise in a number of earlier small clinical trials for chronic midportion Achilles and patellar tendinopathy [111,112]. However, studies are limited and larger, well-performed trials are needed to determine the effectiveness of sclerotherapy [105,113]. The technique does appear to be safe as very few adverse events have been reported.
Injections target abnormal peritendinous blood vessels using ultrasound guidance. Pilot studies have demonstrated the feasibility of this technique for patients with de Quervain's tenosynovitis, flexor carpi ulnaris tendinopathy, supraspinatus tendinopathy, and midportion Achilles tendinopathy [106,114-116]. A retrospective observational study of 113 Achilles tendinopathy patients failed to confirm the initial reports of clinical benefit with polidocanol treatment [117].
Autologous blood and platelet-rich plasma injection — The injection of autologous blood or platelet-rich plasma (PRP), often under ultrasound guidance, is performed with the intention of stimulating a healing response in patients with chronic tendinopathy. High-quality evidence of the efficacy of these treatments is sparse, and well-performed trials are needed. The use of biologic therapies such as PRP for the treatment of tendon and muscle conditions is reviewed in detail separately. (See "Biologic therapies for tendon and muscle injury".)
Dry needling — Needling, with or without injection of other substances, has generally been investigated in patients with tendinopathy that has not responded to conservative management. A narrative review of studies of dry needling in treatment of tendinopathy considered three systematic reviews, seven randomized trials, and six cohort studies of both upper and lower limb tendons [118]. Most studies reported statistically significant improvements in patient symptoms and the authors concluded that available, albeit limited, evidence suggests that dry needling is safe, inexpensive, and effective treatment for tendinopathy. Heterogeneity in treatment protocols, including needling frequency and use of ultrasound guidance, and use of other therapies limit the generalizability of these findings. Dry needling requires training and experience to perform properly, and results may vary in part depending on clinician skill.
Acupuncture — Studies of acupuncture for the treatment of tendinopathy are limited, and the technique should be considered an adjunct for pain relief while the patient performs an appropriate exercise program that stimulates tendon repair. The patient and clinician may wish to consider the cost versus benefit of multiple acupuncture treatments versus fewer but more intensive sessions or versus the one to two that may be used with dry needling interventions. The use of acupuncture for analgesia is discussed separately. (See "Acupuncture".)
A systematic review of four small, limited, randomized trials found acupuncture to be of short-term benefit for the reduction of acute pain in patients with lateral epicondyle tendinopathy, but there was insufficient evidence to support or refute its effect upon long-term outcomes [119].
An unblinded randomized trial of 64 patients with chronic Achilles tendinopathy who received either 24 treatments of acupuncture or a progressive, eccentric resistance exercise program over eight weeks reported improved pain and function (VISA-A score) at 8, 16, and 24 weeks after, with the eight-week difference between the groups of 18.6 points narrowing to an 11.8 point difference in VISA at 24 weeks [120].
A study of 22 patients who had recently failed an eccentric exercise protocol for Achilles tendinopathy compared acupuncture to sham acupuncture [121]. Treatment was delivered in four 30-minute sessions spaced fortnightly over a six-week period and follow up assessment was completed at week 12. Although the VISA-A score improved more in the true acupuncture group and the difference reached statistical significance, these results should be interpreted cautiously given the small number of patients.
Ultrasound therapy — Ultrasound therapy has been available for several decades, but definitive evidence supporting its efficacy in treating tendinopathy is lacking. A systematic review of 13 randomized controlled trials (RCT) involving patellar tendinopathy patients concluded, based upon limited evidence, that ultrasound can likely be excluded as a treatment due to marginal efficacy [122]. Another systematic review of RCTs of physical interventions for lateral elbow tendinopathy found insufficient evidence to support or refute the effectiveness of ultrasound as a lone treatment [58]. A single RCT comparing hyperthermia treatment to continuous ultrasound therapy in patients with either Achilles or patellar tendinopathy concluded that ultrasound treatment was inferior [96]. A systematic review of three trials of interventions for rotator cuff tendinopathy found therapeutic ultrasound to be inferior to laser therapy and of no greater benefit than placebo [47].
Laser therapy — Low-level laser therapy (LLLT; also known as "cold laser") has been available for many years, but convincing evidence of its clinical efficacy is lacking. Despite the development of LLLT dosing guidelines for the treatment of tendinopathies by the World Association of Laser Therapy (WALT), a systematic review of controlled clinical trials reported inconsistent results with 12 studies showing some benefit while 13 reported inconclusive results or no effect [123]. Studies varied in quality and in the laser doses used.
A 2005 systematic review of studies of LLLT for patients with lateral epicondyle tendinopathy concluded that there was no clinically significant effect, either short or long term, compared with placebo [58]. Several controlled trials in which patients were randomly assigned to treatment with LLLT or placebo laser reported that active laser treatment did not improve outcomes beyond those achieved with eccentric exercise [124,125]. Another randomized trial reported no effect of LLLT (using WALT guidelines) as an adjunct to eccentric exercise [126]. However, some trials have reported significant symptom improvement in patients treated with active laser versus placebo [127,128].
INDICATIONS FOR SURGERY — The treatment of chronic tendinopathies involves rehabilitation combined with conservative medical management. Surgical consultation is reasonable if there is no improvement after 6 to 12 months of diligent physical therapy using a well-designed program in combination with adjunct medical treatments and after other conditions have been excluded or managed. (See 'Approach to treatment' above and 'Treatments' above.)
A variety of operative treatments have been advocated, depending upon the location of the tendinopathy and the preferences of the surgeon. Referring clinicians should carefully assess the risks and benefits of surgery. A systematic review concluded that the degree of success claimed in surgical studies of tendinopathy repair correlates inversely with the quality of the study [129,130].
Open surgical procedures for treatment of tendinopathy involve incising the paratendon and removing adhesions, followed by debridement of macroscopically degenerate tissue, or in the case of the shoulder, calcific deposits [131]. Sometimes longitudinal incisions are made in the tendon, with the goal of promoting a repair response [132]. A similar strategy of longitudinal incision and debridement may be achieved arthroscopically [133-135]. Resection or drilling of the tendon's attachment points have also been described [131,136]. This procedure necessarily entails a prolonged recovery (approximately 6 to 12 weeks) due to the time needed for tendon and bone healing.
Minimally invasive surgical procedures have been developed. The advantage of such procedures is that the tendon itself is not disturbed, and thereby, lengthy rehabilitation may be avoided. For the patellar tendon, an arthroscopic procedure involves debriding the area of neovascularization on the posterior surface of the tendon until flow in the neovessels is no longer seen [137]. For midportion Achilles tendinopathy, a similar approach involves stripping or debriding the neovascular area on the anterior surface of the tendon. This procedure may include resection of the associated pathologic plantaris tendon or bursae, if indicated [138]. (See "Achilles tendinopathy and tendon rupture".)
Among the minimally invasive techniques is percutaneous ultrasonic tenotomy (eg, Tenex), which uses a needle to apply high-intensity ultrasound waves to debride tissue, with concurrent tissue lavage. The technique has been used for lateral elbow [139,140], gluteal [141], and other tendinopathies. Further research is required to determine the effectiveness of this approach.
Studies comparing surgery to rehabilitation programs (such as those described above) in the treatment of tendinopathy report equivalent long-term results for function, pain, and overall quality-of-life measures. In a systematic review of 12 randomized trials (two rated good quality and four moderate quality), surgery was found to yield superior results when compared with no treatment or placebo but equivalent results compared with sham surgery and exercise therapy [142]. The authors recommend conservative exercise-based interventions for 12 months before surgery is considered. However, caution should be exercised when interpreting the direct comparisons included in these disparate studies as in many cases surgery was an intervention of last resort and patient cohorts were not equivalent.
Should surgery be needed, limited evidence suggests that arthroscopy yields modestly better results in patient satisfaction and allows for a more rapid return to sport and full activity [143,144]. Minimally invasive and arthroscopic procedures have lower complication rates [145]. A large systematic review of studies of the surgical management of mid-Achilles tendinopathy investigated open, minimally invasive, and endoscopic procedures and noted the wide range of surgical techniques, which made meaningful comparisons difficult [145]. None of the included studies involved a placebo or nonsurgical comparator. Among minimally invasive procedures (five studies), complication rates ranged from 2.9 to 30.6 percent and success rates from 69 to 100 percent.
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: General issues in muscle and tendon injury diagnosis and management" and "Society guideline links: Muscle and tendon injuries of the upper extremity (excluding shoulder)" and "Society guideline links: Muscle and tendon injuries of the lower extremity (excluding Achilles)".)
SUMMARY AND RECOMMENDATIONS
●Presentation and evaluation – Overuse tendinopathy is a clinical syndrome characterized by chronic pain and tendon thickening with a history of repetitive tendon loading. It commonly results from overuse and occurs in workers and athletes. Most patients present after three months of symptoms.
The patient's history should elucidate the changes in training or activity (eg, frequency, duration, intensity) that led to the tendinopathy, and determine the level of function to which the patient aims to return. Validated functional assessment scores can help the clinician to grade symptoms and determine function.
Abnormal biomechanics and/or significant fluctuations in tendon loading while performing common tasks (eg, running, jumping, throwing, or typing on a keyboard) often contribute to tendinopathy. Ideally, these factors should be assessed by an expert and corrected wherever possible. (See 'Patient history and assessment' above and 'Biomechanical modification' above.)
●Management – We suggest that physical rehabilitation, emphasizing slow, progressive, heavy-load exercise, be used to treat chronic tendinopathy (Grade 2B). This approach is preferred to physical therapy without heavy-load exercise, medication or other interventions without physical therapy, or rest alone. A suggested treatment approach is described in the text and summarized in the following algorithm (algorithm 1). During rehabilitation, it is important to limit the volume, intensity, and rate of increase in the loads placed upon the injured tendon outside of the therapeutic exercise program. (See 'Heavy-load resistance training' above and 'Activity modification and tendon load' above.)
A short course of antiinflammatory medication, including glucocorticoids, may be given at the onset of treatment to relieve pain. For the longer-term treatment of chronic tendinopathy, glucocorticoids are potentially harmful and consistently produce poorer outcomes; we suggest they be avoided (Grade 2B). Adjunct therapies to the exercise-based approach described may include stretching, tissue mobilization, ice or heat, topical nitroglycerin, and shock wave therapy. (See 'Treatments' above.)
Multiple alternative therapies for chronic tendinopathy are under investigation. These therapies, many of which involve intratendinous or peritendinous injections designed to stimulate a repair response, have not been studied in large clinical trials, and clear proof of efficacy is lacking. Examples of alternative treatments include prolotherapy, dry needling, sclerotherapy, and injection with autologous blood or platelet-rich plasma. (See 'Unproven and investigational treatments' above and "Biologic therapies for tendon and muscle injury".)
●Indications for surgical consultation – The initial treatment of chronic tendinopathy consists of nonsurgical management. However, it is reasonable to obtain surgical consultation if after 6 to 12 months of diligent physical therapy using a well-designed program in combination with adjunct medical treatments there has been no improvement in symptoms or function. (See 'Indications for surgery' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Karim Khan, MD, who contributed to an earlier version of this topic review.
