Results of Surgical Treatment of Chronic Patellar Tendinosis (Jumper's Knee): A Systematic Review of the Literature

Role of orthobiologics in managing patellar tendinopathy: A narrative review

Patellar tendinopathy is a relatively common cause of anterior knee pain in athletes. It is predominantly seen in sports involving jumping, running, abrupt change in direction like basketball, volleyball, soccer, sprinting and jumping. The main pathophysiology is considered to be repetitive microtrauma at the inferior pole of patella along with a poor healing response. Although eccentric exercises have shown to be beneficial, the improvement is often slow and may result in a less than satisfactory outcome. There is a growing interest of orthobiologics, mainly platelet-rich plasma (PRP) in multiple chronic musculoskeletal pathologies. This narrative review aimed to analyse the current evidence on the role of orthobiologics in the management of recalcitrant patellar tendinopathy. Multiple studies have shown significant clinical improvement with negligible adverse effects on PRP injection for patellar tendinopathy. Most studies assessed report that the effects of PRP are sustained. However, among all studies evaluated, there is a considerable heterogeneity in terms of PRP composition, number of injections, dosage interval and postinjection rehabilitation protocol, pointing to the need for further research to enable standardisation of PRP therapy. Stem cells too have shown potential to be effective as a treatment modality for chronic patellar tendinopathy, but there is limited data to recommend its use outside of research setting or to enable a meaningful comparison to PRP. There is a promising role of orthobiologics in management of chronic patellar tendinopathy not responding to conventional treatment.

Level of Evidence

Not applicable (narrative review).

Patellar Tendon Open Debridement and Reconstruction With Hamstring Tendon Autograft for Severe Patellar Tendinopathy

Patellar tendinopathy is an overuse injury of the patella tendon common in jumping sports or activities. Degeneration of the patellar tendon fibers causes microtears in the tendon, leading to partial patellar tendon tears. If nonoperative treatment fails and the tears are mild, a debridement of the detached tissue with a patella tendon repair can help to reduce pain, promote healing, and improve function. However, if more than 50% of the patella tendon attachment to the inferior pole of the patella is detached, a debridement with a patellar tendon reconstruction is indicated to restore the strength of the patellar tendon. This reconstruction technique uses gracilis and semitendinosus autografts to surround and reconstruct the patellar tendon. Tunnels are drilled horizontally at the tibial tubercle and through the midpoint of the patella for graft passage. This technique can help to improve patient outcomes and reduce some of the risk of failure associated with performing only the debridement when significant partial patellar tendon tearing is present.

Ultrasound-guided electrocoagulation of neovascularisation for persistent patellar tendinopathy in athletes: a cohort study of 25 patients with a mean follow-up of 5 years from the SANTI Study Group

Background

Patellar tendinopathy (PT) is a common condition characterised by persistent patellar tendon pain and dysfunction, particularly in athletes. Neovascularisation is frequently observed in the PT and is associated with increased pain. Ultrasound-guided electrocoagulation of neovascularisation has emerged as a minimally invasive alternative treatment for recalcitrant PT.

Hypothesis/purpose

The purpose of this study was to evaluate the clinical outcomes of ultrasound-guided electrocoagulation of neovascularisation in athletes with persistent PT.

Study design

Case series; level of evidence, IV.

Methods

A retrospective analysis of prospectively collected data was performed on 25 athletes who underwent ultrasound-guided electrocoagulation of neovascularisation for recalcitrant PT. Clinical outcomes including complications, reinterventions and patient-reported outcome measures were recorded. Comparisons between variables were assessed using χ2 test or Fisher's exact test for categorical variables and Student's t-test or Wilcoxon test for quantitative variables.

Results

25 patients were included in the final analysis. 96% returned to their preoperative activity level at a mean of 3.8 months. At a mean follow-up of 5 years 4% did not receive significant benefit from electrocoagulation therapy. Significant improvements were observed in outcome measures, including the Victorian Institute of Sport Assessment Questionnaire for Patients with Patellar Tendinopathy, Kujala score, modified Blazina score and Visual Analogue Scale for pain.

Conclusion

Ultrasound-guided electrocoagulation of neovascularisation for persistent PT in elite athletes resulted in a low complication rate, a high rate and rapid return to sport and a significant improvement in outcome measures.

Surgical treatment of chronic proximal patellar tendon tears grades 3 and 4 using augmentation with quadriceps tendon-bone graft

BACKGROUND

Chronic proximal patellar tendinosis with partial tendon tears represents a multifactorial overuse injury. Several surgical techniques have been described with various outcomes and the return to sports may fail.

HYPOTHESIS

Reconstruction of the proximal patellar tendon with augmentation using a quadriceps tendon-bone (QTB) graft improves knee function in patients presenting with proximal patellar tendinosis and partial tendon tears.

METHODS

Forty-seven patients (32 males, 15 females) with chronic proximal patellar tendinosis and tendon tears grade 3 and 4 were treated between 1992 and 2018. Patients were evaluated retrospectively using the Popkin-Golman (PG) MRI grading system and the removed tendon parts. The Tegner Activity Scale (TAS) and the Numerical Rating Scale (NRS) for pain were used as outcome measures before surgery and at follow up. Complete data were available in 100% of cases at 6 months follow up, and fifteen of them at later follow up.

RESULTS

The average follow up was 1.5 years (range, 0.5-16). The TAS improved from a mean preoperative score of 3.7 to a mean postoperative score of 9.1. The median NRS status decreased from an average of 6.4 to 1.1. Two patients needed additional arthroscopic scar tissue removal.

CONCLUSION

Reconstruction of proximal patellar tendon tears grades 3 and 4 with augmentation using a QTB graft is a valuable surgical salvage procedure in chronic cases. It improves knee function and yields good to excellent results in most cases including high level athletes. The use of MRI with the PG classification of tendon tears is highly recommended.

LEVEL OF EVIDENCE

Therapeutic case series, Level IV.

Patellar tendinopathy: an overview of prevalence, risk factors, screening, diagnosis, treatment and prevention

Patellar tendinopathy (PT), or jumper's knee, is an overuse injury that occurs in professional, as well as recreational, athletes. This condition is a noncontact injury, typically characterized by gradually increasing pain in the patellar tendon. It is prevalent in participants of several sports, but it occurs mostly in jumping sports. The diagnosis of PT is primarily clinical; however, imaging techniques can be useful as well. Risk factors differ between sexes, playing conditions, the kind of sport, playing level and personal characteristics. Screening is an essential tool to assess PT. This condition affects athletic performance and often persists for years. The use of preventative methods is imperative because of the persistence of this condition, especially in elite athletes who sometimes end their career after long and failed treatments. There are a wide variety of treatment and rehabilitation options available, the majority of which are non-operative, such as eccentric exercises, cryotherapy, platelet-rich plasma (PRP) injections, and anti-inflammatory strategies. If conservative treatment fails, surgery is the next most preferable step. Even though there are many surgical treatment methods, there is no clear evidence on what is the most effective approach to address PT. Taking this into consideration, as well as the extent of this clinical entity, novel therapeutic techniques, as well as screening and prevention methods, are expected to emerge in the near future.

A Review of Patellar Tendinopathy in Athletes Involved in Jumping Sports

This review article discusses the anatomy and histopathology of the patellar tendon, as well as the risk factors and common interventions for patellar tendinopathy (PT) with a view to guide clinicians in treating athletes with patellar tendon pain. PT, or jumper's knee, refers to a chronic injury to the patellar tendon that affects athletes who engage in jumping and explosive movements. The condition is characterized by degeneration and disorganization of the collagen fibers in the tendon, an increase in mucoid ground substance, and fibroblast proliferation. Risk factors for patellar tendinopathy include participation in jumping sports, a greater counter-movement jump height, and training on hard surfaces. Nonoperative treatments for patellar tendinopathy include relative rest, stretching and strengthening exercises, and correction of biomechanical abnormalities. Surgery and other procedures, such as extracorporeal shockwave therapy (ESWT) and injection therapies, may be considered for patients who do not respond to conservative measures.

Current Concepts in Patellar Tendinopathy: An Overview of Imaging, Pathogenesis, and Nonoperative and Operative Management

» Approximately 1 in 3 high-impact athletes develops patellar tendinopathy (PT), with the proximal insertion of the patellar tendon being the most commonly affected anatomical site.» Nonoperative treatment options are effective in reducing pain and restoring functionality in most patients with PT. However, operative intervention should be considered when conservative management fails.» A comprehensive review of the literature on surgical procedures, including both open and arthroscopic approaches, was conducted with a specific focus on clinical outcomes and return to sports.» Both open surgery and arthroscopic surgery for PT have demonstrated favorable success rates and return-to-sport outcomes, with arthroscopic treatment potentially expediting the recovery process.

Platelet-rich plasma in the pathologic processes of tendinopathy: a review of basic science studies

Tendinopathy is a medical condition that includes a spectrum of inflammatory and degenerative tendon changes caused by traumatic or overuse injuries. The pathological mechanism of tendinopathy has not been well defined, and no ideal treatment is currently available. Platelet-rich plasma (PRP) is an autologous whole blood derivative containing a variety of cytokines and other protein components. Various basic studies have found that PRP has the therapeutic potential to promote cell proliferation and differentiation, regulate angiogenesis, increase extracellular matrix synthesis, and modulate inflammation in degenerative tendons. Therefore, PRP has been widely used as a promising therapeutic agent for tendinopathy. However, controversies exist over the optimal treatment regimen and efficacy of PRP for tendinopathy. This review focuses on the specific molecular and cellular mechanisms by which PRP manipulates tendon healing to better understand how PRP affects tendinopathy and explore the reason for the differences in clinical trial outcomes. This article has also pointed out the future direction of basic research and clinical application of PRP in the treatment of tendinopathy, which will play a guiding role in the design of PRP treatment protocols for tendinopathy.

Efficacy of Adipose-Derived Mesenchymal Stem Cells and Stromal Vascular Fraction Alone and Combined to Biomaterials in Tendinopathy or Tendon Injury: Systematic Review of Current Concepts

Background and Objectives: Tendon injury and tendinopathy are among the most frequent musculoskeletal diseases and represent a challenging issue for surgeons as well as a great socio-economic global burden. Despite the current treatments available, either surgical or conservative, the tendon healing process is often suboptimal and impaired. This is due to the inherent scarce ability of tendon tissue to repair and return itself to the original structure. Recently, Adipose-derived mesenchymal stem cells (ADSC) and stromal vascular fraction (SVF) have gained a central interest in the scientific community, demonstrating their effectiveness in treatments of acute and chronic tendon disorders in animals and humans. Either enzymatic or mechanical procedures to obtain ADSC and SVF have been described and used in current clinical practice. However, no unified protocols and processes have been established. Materials and Methods: This systematic review aims at providing a comprehensive update of the literature on the clinical application of ADSC enzymatically or mechanically processed to obtain SVF, alone and in association with biomaterials in the local treatment of tendinopathy and tendon injury in vivo, in animal models and humans. The study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Results: Thirty-two articles met our inclusion criteria, with a total of 18 studies in animals, 10 studies in humans and 4 studies concerning the application of biomaterials in vivo in animals. The review of the literature suggests that ADSC/SVF therapy can represent a promising alternative in tendonregenerative medicine for the enhancement of tendon healing. Conclusions: Nevertheless, further investigations and randomized control trials are needed to improve the knowledge, standardize the procedures and extend the consensus on their use for such applications.

Surgical Management of Patellar Tendinopathy Results in Improved Outcomes and High Rates of Return to Sport: A Systematic Review

Although the majority of patients with patellar tendinopathy (PT) can be treated nonoperatively, operative management may be indicated for recalcitrant cases. While several surgical techniques have been described, there is limited understanding of postoperative outcomes and expectations regarding return to activity and sport. The purpose of this study was to characterize the clinical outcomes associated with the surgical management of PT with an emphasis on return to sport (RTS) rates. We hypothesized that surgical management would lead to clinically important improvements in patient-reported outcomes (PROs) with high rates of RTS and RTS at the same level. A comprehensive search of the PubMed, Medline, and Embase databases was performed in December 2020. Level of evidence studies I through IV, investigating results of surgical management for PT (PRO, functional outcomes, pain, and/or RTS), were included. The search was performed in accordance with the Preferred Reported Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Forty clinical studies reporting on surgery for PT satisfied inclusion criteria, with 1,238 total knees undergoing surgery for PT. A comparison of pre- and postoperative Victorian Institute of Sport Assessment, patellar tendon (VISA-P) scores (mean difference: 41.89, p < 0.00001), Lysholm scores (mean difference: 41.52, p < 0.00001), and visual analogue scale (VAS) pain scores (mean difference: 5, p < 0.00001) demonstrated clinically and statistically significant improvements after surgery. The overall RTS rate following operative management was 89.8% (95% confidence interval [CI]: 86.4-92.8, I ² = 56.5%) with 76.1% (95% CI: 69.7.5-81.9, I ² = 76.4%) of athletes returning to the same level of activity. Surgery for PT provides meaningful improvement in patient reported outcomes and pain while allowing athletes to RTS at high rates with levels of participation similar to that of preinjury. Comparative studies of open and/or arthroscopic surgery are still limited but current evidence suggests better rates of RTS for arthroscopic surgery compared with open surgery. This is a systematic review of level-I to -IV studies.

Collagenase-Induced Patellar Tendinopathy with Neovascularization: First Results towards a Piglet Model of Musculoskeletal Embolization

Background: Therapeutic strategies targeting neovessels responsible for musculoskeletal chronic pain have emerged, including neovessels embolization. Our study aimed to develop a large animal model of patellar tendinopathy with neovascularization. Methods: Nine 3-month-old male piglets (18 patellar tendons) received percutaneous injections of increasing doses of collagenase (0 to 50 mg) at day 0 (D0). Tendinopathy was evaluated by ultrasound (D7 and D14). Neovascularization was evaluated visually and on angiographies. Bonar score was used for histological analysis (D14). Correlations were evaluated using Spearman’s rank (Rs) test. Results: Research protocol was well tolerated. All tendons were enlarged with a median increase of 31.58% [25–40.28] at D7 (p = 0.244) at D7 and 57.52% [48.41–91.45] at D14 (p = 0.065). Tendons with collagenase injection had more hypoechoic changes, with one tendon rupture (p = 0.012). Neovascularization was reported above 5 mg collagenase (p < 0.01) at D7 and D14 with dose-related neovessels induction (Rs = 0.8, p < 0.001). The Bonar score increased above 5 mg collagenase, correlated with the dose (Rs = 0.666, p = 0.003). Conclusions: The study shows the feasibility, safety and reproducibility of this new large animal model of patellar tendinopathy with neovascularization after collagenase injection. It will allow studying new treatments on direct embolization of neovessels by endovascular approach.

Adipose micro-grafts enhance tendinopathy healing in ovine model: An in vivo experimental perspective study

In Europe, approximatively 100 000 to 500 000 tendon repairs are performed every year. These procedures are associated with a considerable rate of postoperative complications (from 6% to 11%). Autologous micro-grafts (AAMG) and stromal vascular fraction (SVF) have been shown to improve tendon healing in 60% to 70% of treated rodents. The purpose of this study was to evaluate the effects of AAMG in a sheep model with tendinopathy. We used sheep models because, as a large animal, they are more comparable to humans. The hypothesis was that SVF injection would improve tendon healing compared with the control group, reducing inflammatory and matrix degrading, while increasing anti-inflammatory expression and collagen synthesis in the early stage of tendon injury. Sixteen Apennine sheep aged 2 to 5 years underwent 500 UI type I collagenase injection into both common calcaneal tendons (CCT) to induce tendinopathy. After 15 days (T0), one CCT in every ovine underwent randomly to 2.5 mL of AAMG obtained by mechanical disruption and the contralateral CCTs received no treatment. Clinical, ecographic, and sonographic evaluations were performed after 4 weeks (T1) and 8 weeks (T2). Histological, immunohistochemical, real-time polymerase chain reaction (RT-PCR), and biomechanical evaluations were performed at T2. At T2, the treated group showed a final tendon diameter (9.1 ± 1.4 mm) and a hardness expression (62%) that were similar to the original healthy tendon (8.1 ± 1.1 mm; 100%), with a significant recovery compared with the control group (9.5 ± 1.7 mm; 39%). Moreover, histological analysis of the treated group revealed an improvement in the fiber orientation score, fiber edema score, infiltrative-inflammatory process, and necrosis score (4.3 ± 3.3) compared with control group (8.8 ± 2.9). Immunohistochemically, the treated group showed high expression of collagen 1, Factor VIII and significantly low expression of collagen 3. These data were confirmed by RT-PCR analysis. The study findings suggested that AAMGs obtained through mechanical disruption present a safe, efficient, and reliable technique, enhancing tendon healing.

Bioinductive Collagen Implant Augmentation for the Repair of Chronic Lower Extremity Tendinopathies: A Report of Two Cases

In this report, we present two cases of refractory chronic lower extremity tendinopathies treated with collagen bioinductive implant augmentation: a 20-year-old male football player with chronic patellar tendinopathy and a 40-year-old active female with chronic proximal hamstring tendinopathy. We demonstrate that bioaugmentation may represent an effective strategy in the surgical treatment of chronic tendinopathies. Both patients were able to return to their pre-injury activity levels at an accelerated rate.

Narrative: Review of Anterior Knee Pain Differential Diagnosis (Other than Patellofemoral Pain)

PURPOSE OF REVIEW

This review presents a framework for constructing a differential diagnosis for chronic anterior knee pain associated with overuse other than patellofemoral pain. Traumatic, systemic, and pediatric injuries will not be covered.

RECENT FINDINGS

From superficial to deep, the anterior knee can be conceptually organized into four layers: (1) soft tissue, (2) extensor mechanism, (3) intracapsular/extrasynovial, and (4) intra-articular. From superficial to deep, diagnoses to consider include bursitis, patellar and quadriceps tendinosis, fat pad impingement, and plica syndromes.

Differences in the magnetic resonance imaging parameter T2* may be identified during the course of canine patellar tendon healing: a pilot study

Background

Previous studies have utilized ultrashort echo (UTE) magnetic resonance imaging (MRI), and derived T2* maps, to evaluate structures with highly ordered collagen structures such as tendon. T2* maps may provide a noninvasive means to assess tendon damage and healing. This pilot study evaluated the longitudinal relationship of an induced mechanical strain on the patellar tendon with corresponding UTE T2* metrics, histologic and biomechanical evaluation at two post-operative time points.

Methods

A total of 27 patellar tendons in male Beagles were surgically subjected to stretching by a small diameter (SmD) or a large diameter (LgD) diameter rod to induce damage due to strain, and evaluated at 4- and 8-week intervals using quantitative MRI (qMRI), biomechanical testing, and histology. A separate set of 16 limbs were used as controls.

Results

The tendons experienced a 67% and 17% prolongation of short T2* values as compared to controls at 4 and 8 weeks post-operatively, respectively. Histologic analysis displayed a trend of increased collagen disruption at 4 weeks followed by presence of greater organization at 8 weeks. Biomechanical evaluation found a reduction of tendon modulus and failure strain at both time points, and an increase in cross-sectional area at 4 weeks as compared to controls.

Conclusions

These findings display tendon healing in response to an imposed strain and present the utility of qMRI to evaluate longitudinal differences of patellar tendon T2* values in a model of induced subclinical tendon damage. The qMRI technique of UTE provides a means to non-invasively evaluate the healing process of a mechanically damaged tendon.

Management of Achilles and patellar tendinopathy: what we know, what we can do

Tendinopathies are challenging conditions frequent in athletes and in middle-aged overweight patients with no history of increased physical activity. The term “tendinopathy” refers to a clinical condition characterised by pain, swelling, and functional limitations of tendons and nearby structures, the effect of chronic failure of healing response. Tendinopathies give rise to significant morbidity, and, at present, only limited scientifically proven management modalities exist. Achilles and patellar tendons are among the most vulnerable tendons, and among the most frequent lower extremity overuse injuries. Achilles and patellar tendinopathies can be managed primarily conservatively, obtaining good results and clinical outcomes, but, when this approach fails, surgery should be considered. Several surgical procedures have been described for both conditions, and, if performed well, they lead to a relatively high rate of success with few complications. The purpose of this narrative review is to critically examine the recent available scientific literature to provide evidence-based opinions on these two common and troublesome conditions.

Results of Arthroscopic Treatment of Chronic Patellar Tendinopathy

BACKGROUND

The surgical treatment of chronic patellar tendinopathy could be open or arthroscopic. A general agreement on the best surgical treatment option is still lacking.

PURPOSE

The aim of our study was to evaluate the clinical results after a minimally invasive arthroscopic treatment of chronic patellar tendinopathy including a resection of the lower patellar pole.

METHODS

The study included 14 patients with a mean age of 26 years and chronic patellar tendinopathy refractory to non-operative treatment of more than 6 months. All patients underwent arthroscopic debridement of the adipose tissue of the Hoffa's body posterior to the patellar tendon, debridement of abnormal patellar tendon and resection of the lower patellar pole. Preoperative and postoperative evaluation was undertaken using clinical examination, magnetic resonance imaging (MRI) and the Lysholm and Victorian Institute of Sport Assessment-Patella (VISA-P) scores. Return to sports and postoperative complications were also assessed. The mean follow-up was 12.2 ± 0.9 months.

RESULTS

All 14 patients continued with sport activities, but only 12 of them (85.7%) achieved their presymptom sporting level. The median time to return to preinjury level of activity was 3.9 ± 0.8 months. Patients showed a major improvement in the mean Lysholm score from 51.1 ± 3.8 to 93.4 ± 4.2 (p=0.001) and in the mean VISA-P score from 42.1 ± 3.5 to 86.7 ± 8.4 (p=0.001) There were no postoperative complications.

CONCLUSION

We found that this arthroscopic technique gives reduced morbidity and satisfactory outcome resulting in significantly faster recovery and return to sports in patients with chronic patellar tendinopathy.

Treatment of patellar and hamstring tendinopathy with platelet-rich plasma in varsity collegiate athletes: A case series

Patellar and hamstring tendinopathy are common injuries among elite athletes. Platelet-rich plasma (PRP) has emerged as a promising new therapy for accelerating healing and shortening recovery in patients with these conditions. We present 15 cases of PRP injection used for either patellar or hamstring tendinopathy in varsity collegiate athletes at a single institution. All of the athletes in our case series with hamstring or patellar tendinopathy were fully able to return to sport. Three of the athletes with patellar tendinopathy were referred for surgery, while none of the athletes with hamstring strain underwent a subsequent surgical procedure.

The effect of surgery on patellar tendinopathy: Novel use of MRI questions the exploitability of the rat collagenase model to humans

BACKGROUND

patellar tendinopathy is an overuse condition most commonly affecting jumping athletes. Surgery is reserved for refractory cases; however, it lacks high level clinical evidence and basic science to support its use. The purpose of this study was to determine the biomechanical and histological response of surgical excision on patellar tendinopathy in the rat collagenase tendinopathy model and correlate MRI findings.

METHODS

Forty-eight Long Evans rats were divided into three groups: i) no patellar tendinopathy with surgical excision, ii) patella tendinopathy with surgical excision, and iii) patellar tendinopathy with no surgical excision. Endpoints included histology, mechanical testing, and MRI pre- and post-surgical intervention at one and four weeks.

RESULTS

No difference in failure load or histological grading was seen between the groups at all time points. MRIs showed initial loss of tendon continuity followed by complete healing with elongated and thickened tendons in all groups.

CONCLUSIONS

While other research has reported immunohistochemistry and histology of collagenase-induced tendinopathy may be correlated with human pathogenesis, the novel MRI findings from our study suggest that the rat collagenase tendinopathy surgical model may be limited when extrapolating to humans. Further work is needed to determine if any correlation exists between the dosing, location, and animal effect of the collagenase injection model with MRI findings. This is needed before any collagenase model can be used to determine the effect of surgery in the pathogenic response to patella tendinopathy.

Surgical Technique for Chronic Proximal Patellar Tendinopathy (Jumper's Knee)

Chronic proximal patellar tendinopathy is a challenging condition for its troublesome management in the active patient and difficulty in defining the failure of conservative treatment to indicate surgery. Usually, patients with chronic proximal patellar tendinopathy have already tried several physiotherapeutic modalities and are away from their preferred physical activities for variable periods. The current literature presents some open and even arthroscopic options for treating recalcitrant patellar tendinopathy using a variable magnitude of resources and costs. The purpose of this article was to depict a very simple and inexpensive surgical option for treating this condition, which can be applied worldwide.

Surgery for patellar tendinopathy (jumper's knee)

BACKGROUND

Patellar tendinopathy is an overuse condition that commonly affects athletes. Surgery is usually offered if medical and physical therapies fail to treat it effectively. There is variation in the type of surgery performed for the condition.

OBJECTIVES

To assess the benefits and harms of surgery for patellar tendinopathy in adults.

SEARCH METHODS

We searched the following databases, to 17 July 2018: the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Library, OVID MEDLINE, OVID Embase, clinical trial registries (www.ClinicalTrials.gov) and the WHO trials portal (www.who.int/ictrp/en/).

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) that compared surgical techniques (open or arthroscopic) with non-operative treatment (including placebo surgery, exercise or other non-surgical modalities) in adults with patellar tendinopathy.Major outcomes assessed were knee pain, function, quality of life, participant global assessment of success, withdrawal rate, proportion with adverse events and proportion with tendon rupture.

DATA COLLECTION AND ANALYSIS

Two review authors selected studies for inclusion, extracted trial characteristics and outcome data, assessed the risk of bias and assessed the quality of the evidence using GRADE.

MAIN RESULTS

Two trials (92 participants) met our inclusion criteria. Participants in both trials were followed for 12 months. Neither trial compared surgery to placebo surgery. One trial (40 randomised participants) compared open surgical excision with eccentric exercises, and the other compared arthroscopic surgery with sclerosing injections (52 randomised participants). Due to the nature of the interventions, neither the participants or the investigators were blinded to the group allocation, resulting in the potential for performance and detection bias. Some outcomes were selectively not recorded, leading to reporting bias. Overall, the certainty of the evidence from these studies was low for all outcomes due to the potential for bias, and imprecision due to small sample sizes.Compared with eccentric exercises, low-certainty evidence indicates that open surgical excision provides no clinically important benefits with respect to knee pain, function or global assessment of success. At 12 months, mean knee pain - measured by pain with standing jump on a 10-point scale (lower scores indicating less pain) - was 1.7 points (standard deviation (SD) 1.6) in the eccentric training group and 1.3 (SD 0.8) in the surgical group (one trial, 40 participants). This equates to an absolute pain reduction of 4% (ranging from 4% worse to 12% better, the minimal clinically important difference being 15%) and a relative reduction in pain of 10% better (ranging from 30% better to 10% worse) in the treatment group. At 12 months, function on the zero- to 100-point Victorian Institute of Sport Assessment (VISA) scale was 65.7 (SD 23.8) in the eccentric training group and 72.9 (SD 11.7) in the surgical group (one trial, 40 participants). This equates to an absolute change of 7% better function (ranging from 4% worse to 19% better) and relative change of 25% better (ranging from 15% worse to 65% better, the minimal clinically important difference being 13%). Participant global assessment of success was measured by the number of people with no pain at 12 months: 7/20 participants in the eccentric training group reported no pain, compared with 5/20 in the open surgical group (risk ratio (RR) 0.71 (95% CI 0.27 to 1.88); one trial, 40 participants). There were no withdrawals, but five out of 20 people from the eccentric exercise group crossed over to open surgical excision. Quality of life, adverse events and tendon ruptures were not measured.Compared with sclerosing injection, low-certainty evidence indicates that arthroscopic surgery may provide a reduction in pain and improvement in participant global assessment of success, however further studies are likely to change these results. At 12 months, mean pain with activities, measured on a 100-point scale (lower scores indicating less pain), was 41.1 (SD 28.5) in the sclerosing injection group and 12.8 (SD 19.3) in the arthroscopic surgery group (one trial, 52 participants). This equates to an absolute pain reduction of 28% better (ranging from 15% to 42% better, the minimal clinically important difference being 15%), and a relative change of 41% better (ranging from 21% to 61% better). At 12 months, the mean participant global assessment of success, measured by satisfaction on a 100-point scale (scale zero to 100, higher scores indicating greater satisfaction), was 52.9 (SD 32.6) in the sclerosing injection group and 86.8 (SD 20.8) in the arthroscopic surgery group (one trial, 52 participants). This equates to an absolute improvement of 34% (ranging from 19% to 49%). In both groups, one participant (4%) withdrew from the study. Functional outcome scores, including the VISA score, were not reported. Quality-of-life assessment, adverse events, and specifically the proportion with a tendon rupture, were not reported.We did not perform subgroup analysis to assess differences in outcome between arthroscopic or open surgical excision, as we did not identify more than one study with a common comparator.

AUTHORS' CONCLUSIONS

We are uncertain if surgery is beneficial over other therapeutic interventions, namely eccentric exercises or injectables. Low-certainty evidence shows that surgery for patellar tendinopathy may not provide clinically important benefits over eccentric exercise in terms of pain, function or participant-reported treatment success, but may provide clinically meaningful pain reduction and treatment success when compared with sclerosing injections. However, further research is likely to change these results. The evidence was downgraded two levels due to the small sample sizes and susceptibility to bias. We are uncertain if there are additional risks associated with surgery as study authors failed to report adverse events. Surgery seems to be embedded in clinical practice for late-stage patella tendinopathy, due to exhaustion of other therapeutic methods rather than evidence of benefit.

Nonsurgical Treatments of Patellar Tendinopathy: Multiple Injections of Platelet-Rich Plasma Are a Suitable Option: A Systematic Review and Meta-analysis

BACKGROUND

Patellar tendinopathy is a condition characterized by anterior knee activity-related pain. It has a high incidence among athletes engaged in jumping sports and may become a chronic condition. Nonoperative management is the first choice in these patients, and several nonsurgical treatment options have been proposed. Nonetheless, clear indications on the most effective approach to address patellar tendinopathy are still lacking.

PURPOSE

To analyze the evidence on nonoperative options to treat chronic patellar tendinopathy through a systematic review of the literature and to perform a meta-analysis to identify the most effective nonsurgical option.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

The search was conducted with the PubMed and Cochrane databases on January 4, 2017. All clinical English-language reports of any level of evidence on nonsurgical treatment of patellar tendinopathy were included. The quality of each article was assessed by use of the Coleman score. A meta-analysis was performed on all articles reporting the Victorian Institute of Sport Assessment scale for patellar tendinopathy to evaluate the results of the most described treatments.

RESULTS

A total of 70 studies involving 2530 patients were included in the qualitative data synthesis. The Coleman score showed an overall poor study quality. The most described treatment groups that could be included in the meta-analysis were reported in 22 studies on eccentric exercise, extracorporeal shockwave therapy (ESWT), and platelet-rich plasma (PRP). Single and multiple PRP injections were evaluated separately. Eccentric exercise therapies obtained the best results ( P < .05) at short-term (<6 months, mean 2.7 ± 0.7 months). However, multiple injections of PRP obtained the best results ( P < .05), followed by ESWT and eccentric exercise, at long-term follow-up (≥6 months, mean 15.1 ± 11.3 months).

CONCLUSION

The literature documents several nonsurgical approaches for the treatment of chronic patellar tendinopathy with important limitations in terms of study quality. The available evidence showed an overall positive outcome, but some differences have been highlighted. Eccentric exercises may seem the strategy of choice in the short-term, but multiple PRP injections may offer more satisfactory results at long-term follow-up and can be therefore considered a suitable option for the treatment of patellar tendinopathy.

Quadriceps tendinopathy: a review, part 2-classification, prognosis, and treatment

Overuse injuries of the extensor mechanism of the knee are common in both athletes and non-athletes and usually occur during activities associated with repetitive loading, stress, and knee extension. Numerous reports have been published describing extensor mechanism injuries in athletes, but there is a paucity of studies that focus on quadriceps tendinopathy in the non-athlete population. In addition, there is no universally accepted classification system for tendon pathology. Therefore, we performed a comprehensive literature review of these studies. This review consists of 2 parts. In the previous part we reviewed: (I) epidemiology and (II) diagnosis of quadriceps tendinopathy in the athlete as well as the general population. In this part we discuss: (I) classification; (II) prognosis; and (III) treatment results.

Surgery in Tendinopathies

Tendinopathies are challenging. The term "tendinopathy" refers to clinical condition characterized by pain, swelling, and functional limitations of tendons and nearby structures. Tendinopathies give rise to significant morbidity, and, at present, only limited scientifically proven management modalities exist. Achilles and patellar tendons are among the most vulnerable tendons, and among the most frequent lower extremity overuse injuries. Achilles and patellar tendinopathies can be managed conservatively and surgically. Several surgical procedures have been described for both conditions, and, if performed well, they lead to a relatively higher rate of success with low complication.

Proposing a Patellar Tendinopathy Screening tool following a systematic review

BACKGROUND

Patellar tendinopathy (PT) is an overuse injury of the knee. The mechanism of injury is associated with repetitive stress on the patellar tendon of the knee as a result of explosive movement. Patellar tendinopathy is prevalent in all populations and is associated with intrinsic and extrinsic risk factors.

OBJECTIVES

Primarily, the objective was to report on the intrinsic and extrinsic risk factors for PT, entailing a systematic review of the literature; the secondary objective was to use these risk factors to compile a proposed PT screening tool from the review and standard outcome measures.

METHOD

A systematic review was undertaken according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Elimination criteria of the articles included duplicates, titles, abstracts and methodological quality. The evidence was collected, characterised with regard to the intrinsic and extrinsic risk factors and summarised descriptively.

RESULTS

The search yielded 157 feasible articles prior to commencement of article elimination. Six articles were included with a mean methodological quality score of 69%. Eight intrinsic and five extrinsic risk factors were identified. These identified risk factors are all relevant to the pathology and formed the basis for a proposed PT screening tool. The Victorian Institute of Sports Assessment for Patellar Tendinopathy Questionnaire, Visual Analog Scale and the Pain Provocation Test are also included in the proposed test.

CONCLUSION

Intrinsic and extrinsic risk factors for PT were identified, and consequently, the proposed PT screening tool was formulated for possible future testing in appropriate studies.

CLINICAL IMPLICATIONS

Prevention of PT through intrinsic and extrinsic risk factor identification, and implementation in the clinical setup as a possible outcome measurement tool with which to verify functional improvement in PT rehabilitation.

Refractory patellar tendinopathy treated by arthroscopic decortication of the inferior patellar pole in athletes: Mid-term outcomes

BACKGROUND

This study aimed to evaluate the clinical outcomes of arthroscopic decortication of the inferior patellar pole in athletes with refractory chronic patellar tendinopathy.

METHODS

Thirty-seven athletes in whom conservative management for at least six months failed underwent arthroscopic patellar tendon debridement and decortication of the inferior pole of the patella. Clinical outcomes were evaluated using subjective knee scores and isokinetic muscle strength tests. The average duration taken and sports participation level were also assessed.

RESULTS

The mean follow-up period was 51.3 ± 14.8 months. At the last follow-up, all improvements in subjective knee scores including Lysholm score, International Knee Documentation Committee (IKDC) subjective score, Victorian Institute of Sport Assessment -Patella (VISA-P) score, and Kujala score were statistically significant (p<.001). Tegner activity scale improved from 6.5±1.0 to 8.9±0.8 (p<.001). Limb symmetry index for extensor peak torque improved from 71.4±19.6% to 92.7±21.7% (p<.001). Thirty-two (86.5 %) athletes were able to return to full sports activities in a mean 3.5±1.7months, and 27 (73%) athletes maintained their previous sports activity level at the last follow-up. Symptoms recurred in two (5.2%).

CONCLUSIONS

Arthroscopic decortication of the inferior pole of the patella showed satisfactory clinical results and high rates of return to sports at mid-term follow-up in professional athletes with refractory chronic patellar tendinopathy. This technique could be an invasive, safe, and effective treatment for chronic patellar tendinopathy in professional athletes who want a faster return to sports.

LEVEL OF EVIDENCE

Level IV, case series.

[Jumper's Knee]

Zusammenfassung. Sportliche Aktivitäten mit Sprungabläufen stellen für die Kniegelenke eine mechanische Herausforderung dar. Häufig projizieren sich chronisch auftretende, atraumatische Beschwerden auf den Patellaunterpol, welcher pathomorphologisch eine patellare Tendinopathie entspricht. Extrinsische und intrinsische Risikofaktoren können unterschieden werden. In der klinischen Untersuchung zeigt sich ein meist unauffälliges Knie mit einer Druckdolenz am kaudalen Teil der Kniescheibe beim Übergang zum Ligamentum patellae. In der Bildgebung ist sonografisch ein degenerierter Sehnenanteil der tiefen Patellarsehne zu erkennen, der magnettomografisch mit Hyperintensität des Hoffa-Körpers einhergehen kann. Abhängig von der klinischen Entwicklung wird das Jumper’s Knee nach Blazina Grad I–IV eingeteilt. Bis zu 90 % der Patienten können konservativ therapiert werden. Operativ stehen offene und arthroskopische Verfahren mit ordentlichem Resultat zur Verfügung.

Arthroscopic patellar release for treatment of chronic symptomatic patellar tendinopathy: long-term outcome and influential factors in an athletic population

BACKGROUND

Arthroscopic patellar release (APR) is utilized for minimally invasive surgical treatment of patellar tendinopathy. Evidence regarding long-term success following the procedure is limited. Also, the influence of age and preoperative performance level, are incompletely understood. The aim of this study was to investigate whether APR translates into sustained pain relief over a long-term follow-up in athletes undergoing APR. Furthermore, we analyzed if age influences clinical and functional outcome measures in APR.

METHODS

Between 1998 and 2010, 30 competitive and recreational athletes were treated with APR due to chronic refractory patellar tendinopathy. All data were analyzed retrospectively. Demographic data, such as age or level of performance prior to injury were extracted. Clinical as well as functional outcome measures (Swedish Victorian Institute of sport assessment for patella (VISA-P), the modified Blazina score, pain level following exercise, return to sports, and subjective knee function were assessed pre- and postoperatively.

RESULTS

In total, 30 athletes were included in this study. At follow-up (8.8 ± 2.82 years), clinical and functional outcome measures such as the mean Blazina score, VISA-P, VAS, and subjective knee function revealed significant improvement compared to before surgery (P < 0.001). The mean time required for return to sports was 4.03 ± 3.18 months. After stratification by age, patients younger than 30 years of age yielded superior outcome in the mean Blazina score and pain level when compared to patients ≥30 years (P = 0.0448). At 8 years of follow-up, patients yielded equivalent clinical and functional outcome scores compared to our previous investigation after four years following APR.

CONCLUSION

In summary, APR can be regarded a successful, minimally invasive, and sustained surgical technique for the treatment of patella tendinopathy in athletes. Younger age at surgery may be associated with improved clinical and functional outcome following APR.

Anterior Knee Impingement in a High-Level Football Punter: A Case Report and Description of the Active-Passive Knee Extension Test

A 22-year-old football punter complained of anterior knee pain deep to his patellar tendon that occurred every time the knee of his kicking leg reached full extension during a punt. Arthroscopy confirmed anterior impingement between a fibrous tissue eminence directly anterior to his anterior cruciate ligament (ACL) and the intercondylar roof in full extension. With the eminence removed, full extension no longer caused impingement as demonstrated arthroscopically. He resumed punting at maximal effort 6 weeks postoperatively without pain. We report the active-passive knee extension test, a physical examination maneuver designed to identify patients with anterior knee impingement between tissue anterior to the ACL and the intercondylar roof. This test is a helpful part of the clinical examination in detecting these lesions.

Revision Surgery for Failed Patellar Tendinopathy Exploration

Chronic patellar tendinopathy affects athletes, with a higher incidence in high-impact sporting activities. It can seriously impair sports activities. Many patients respond well to conservative treatment, but about 10% of them are refractory to conservative treatment. In these cases, surgery is indicated. Multiple surgical techniques have been reported, including both open and arthroscopic procedures with good results. However, in a small percentage of patients surgery is unsuccessful. This group of patients presents a major challenge, as options are limited. We describe our surgical approach in the management of recalcitrant patellar tendinopathy.

[Evidence-based therapy for tendinopathy of the knee joint : Which forms of therapy are scientifically proven?]

Tendinopathy in the region of the knee joint is a common pathological disorder. People active in sports, in particular, have a high probability of suffering from tendinopathy. Despite its high clinical relevance, the level of evidence of therapy options for tendinopathy in the knee region differs greatly. This review gives an overview of current evidence levels for therapy options in tendinopathy of the quadriceps, patellar and pes anserinus insertion tendons as well as of the distal iliotibial tract tendon. The treatment with platelet-rich plasma showed a significantly better outcome when used correctly and treatment with shock waves, operative treatment and sclerotherapy have also shown positive effects. Treatment with corticosteroid injections and with oral non-steroidal anti-inflammatory drugs (NSAID) showed positive short-term effects (follow-up ±4 weeks). No reasonable data are available for the treatment of tendinopathy in the knee region by acupuncture, fascial therapy or cryotherapy. The use of kinesio taping showed no significant relief from complaints compared with standard conservative treatment. The use of multimodal therapy without evidence is, therefore, particularly common in elite athletes.

Surgical Technique: Jumper's Knee-Arthroscopic Treatment of Chronic Tendinosis of the Patellar Tendon

Chronic patellar tendinosis (jumper's knee) is a common problem among athletes. Conservative treatment is successful in most of the cases including, among others, the use of nonsteroidal anti-inflammatory drugs, local cryotherapy, eccentric muscle training, limitation of sports activity, and local infiltration. In approximately 10% of conservatively treated patients, conservative treatment fails and surgery is required. Different open and arthroscopic surgical techniques have been described in the literature. The presented all-arthroscopic surgical technique for the treatment of chronic patellar tendinosis includes debridement of soft tissue at the lower patellar pole and resection of the bony lower patellar pole. It leads to excellent clinical results comparable to described open treatment and provides the benefits of a minimally invasive and safe procedure with a faster recovery and return to sporting activities after surgery. An additional bony resection in case of a prominent lower patellar pole does not lead to a significant extension of the operation time and may avoid a relapse or treatment failure in selective cases. Therefore, arthroscopic treatment such as the presented technique may be the preferred method for surgical treatment of chronic patellar tendinosis.

Patellar Tendinopathy: Diagnosis and Treatment

Patellar tendinopathy is a common cause of pain in athletes' knees. Historically, it has been related to jumping sports, such as volleyball and basketball. Repetitive jumping generates a considerable load of energy in the extensor mechanism, leading to symptoms. The main pathophysiologic phenomenon in patellar tendinopathy is tendinosis, which is a degenerative disorder rather than an inflammatory disorder; therefore, the other popular term for this disease, tendinitis, is not appropriate. The nonsurgical treatment of patellar tendinopathy is focused on eccentric exercises and often has good results. Other experimental options, with variable levels of evidence, are available for recalcitrant cases. Surgical treatment is indicated for cases that are refractory to nonsurgical treatment. Open or arthroscopic surgery can be performed; the two methods are comparable, but arthroscopic surgery results in a faster recovery time.

Arthroscopic Treatment of Patellar Tendinopathy: Use of 70° Arthroscope and Superolateral Portal

Surgical treatment of recalcitrant patellar tendinopathy includes both the open surgical approach and minimally invasive arthroscopic debridement. A variety of arthroscopic techniques have been described that involve the use of a standard 30° arthroscope and standard anterolateral and anteromedial portals. As a result, visualization of the infrapatellar region can be variable, and it may be necessary to create additional portals. A 70° arthroscope provides the advantage of a wider field of view to the surgeon. By placing a 70° arthroscope through a superolaterally created portal around the knee joint, the surgeon acquires a complete view of the infrapatellar region and patellar tendon. Thus, debridement of the pathologic area can be accomplished just by the use of an additional working portal, typically the anterolateral one. This technical note describes a technique that involves the use of a 70° arthroscope for the treatment of patellar tendinopathy.

Editorial Commentary: Arthroscopy Is Preferred Over Open Surgery for Patellar Tendonitis

Jumper's knee is generally managed without surgery, but for patellar distal pole or midsubstance tendonitis (or tendinosis), if surgery is indicated, arthroscopic surgery is as effective as open, with faster return to play.