Patellar tendinopathy in athletes: current diagnostic and therapeutic recommendations

The Role of Perioperative Nutritional Status and Supplementation in Orthopaedic Surgery: A Review of Postoperative Outcomes

» Identification of malnourished and at-risk patients should be a standardized part of the preoperative evaluation process for every patient.» Malnourishment is defined as a disorder of energy, protein, and nutrients based on the presence of insufficient energy intake, weight loss, muscle atrophy, loss of subcutaneous fat, localized or generalized fluid accumulation, or diminished functional status.» Malnutrition has been associated with worse outcomes postoperatively across a variety of orthopaedic procedures because malnourished patients do not have a robust metabolic reserve available for recovery after surgery.» Screening assessment and basic laboratory studies may indicate patients' nutritional risk; however, laboratory values are often not specific for malnutrition, necessitating the use of prognostic screening tools.» Nutrition consultation and perioperative supplementation with amino acids and micronutrients are 2 readily available interventions that orthopaedic surgeons can select for malnourished patients.

Association Between Patellar Tendon Abnormality and Land-Jump Biomechanics in Male Collegiate Basketball Players During the Preseason

Background

Patellar tendinopathy is a degenerative condition that predominantly affects jumping athletes. Symptoms may be subtle or nonexistent at preseason, but structural abnormalities may be present. Assessing patellar tendon abnormality (PTA) through magnetic resonance imaging (MRI) and ultrasound (US) and classifying symptoms using the Victorian Institute for Sport Assessment-Patellar tendon (VISA-P) may provide useful insights if combined with biomechanics measurements.

Purpose

To (1) assess whether land-jump biomechanical patterns are associated with clinically pertinent PTA as seen on imaging and through VISA-P scores and (2) model the contributing risk and accuracy of biomechanics to classify PTA and symptomatic observations.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A total of 26 National Collegiate Athletic Association Division I and II male basketball players (n = 52 limbs) were recruited during the preseason. We collected VISA-P scores, bilateral PTA through US and MRI morphology measurements, and bilateral 3-dimensional lower extremity kinematics and kinetics measurements from a land-jump test from an 18-inch-high (45.7-cm-high) box. Statistically, each limb was treated independently. The association of biomechanics with PTA and symptoms (VISA-P score <80) was tested with multivariate models and post hoc tests. Logistic regression modeled relative risk and accuracy of biomechanical variables to classify PTA and symptomatic limbs.

Results

There were 19 to 24 limbs with PTA depending on US and MRI measurements. Differences in hip and knee kinematic strategies and ground-reaction loads were associated with PTA and symptomatic limbs. Peak landing vertical ground-reaction force was significantly decreased (169 ± 26 vs 195 ± 29 %body weight; P = .001), and maximum hip flexion velocity was significantly increased (416 ± 74 vs 343 ± 94 deg/s; P = .005) in limbs with versus without PTA on imaging. Knee flexion at the initial contact was decreased in symptomatic versus healthy limbs (17°± 5° vs 21°± 5°, respectively; P = .045). Regression models classified PTA limbs and symptomatic limbs with 71.2% to 86.5% accuracy. Hip and knee maximum flexion velocity and vertical ground-reaction force variables were most common across models observing clinically pertinent PTA.

Conclusion

Our findings suggested that functional kinematic and kinetic biomechanical strategies at the hip and knee were associated with PTA, identified on imaging, and symptomatic limbs.

Platelet-rich plasma for jumper's knee: a comprehensive review of efficacy, protocols, and future directions

PURPOSE

This comprehensive review evaluates the current state of platelet-rich plasma (PRP) treatment for jumper's knee, also known as patellar tendinopathy. The aim is to assess the efficacy of PRP as a therapeutic option compared to other available procedures, investigate the benefits and potential drawbacks of PRP infiltration, and provide insights into the optimal protocols for PRP preparation and administration.

METHODS

A comprehensive literature search of English articles published up to June 2023 was conducted using PubMed and Scopus databases. Studies evaluating PRP for treating jumper's knee or patellar tendinopathy were analyzed to assess the current state of research in this field.

RESULTS

PRP has demonstrated promising results in promoting cellular remodeling and accelerating the healing process in the jumper's knee. It shows potential benefits in pain reduction, improved function, and accelerated recovery. However, the efficacy of PRP varies depending on patient characteristics, disease severity, and the specific administration methodology. Establishing standardized PRP preparation and administration protocols are necessary to optimize its effectiveness. Further research is needed to define appropriate patient selection criteria and refine the application of PRP therapy in patellar tendinopathy management.

CONCLUSION

Jumper's knee is commonly managed conservatively, but there is a lack of consensus on further treatment options. PRP treatment holds promise in promoting tissue healing and repair. However, standardized protocols for PRP preparation and administration, as well as optimal dosage and number of injections, require further investigation to enhance its efficacy. Continued research efforts are necessary to ascertain the precise role of PRP and its refinement in the management of patellar tendinopathy.

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.

The effect of fatigue on spike jump biomechanics in view of patellar tendon loading in volleyball

BACKGROUND AND OBJECTIVE

Patellar tendinopathy (PT) is a highly prevalent overuse injury in volleyball and is often linked with overloading of the patellar tendon. Little is known, however, about whether and how patellar tendon loading is affected by fatigue during the most challenging jump activity in volleyball. Therefore, this study investigates the effect of a high-intensity, intermittent fatigue protocol on movement alterations in terms of patellar tendon loading during a volleyball spike jump.

METHODS

Forty-three male volleyball players participated in this study. Three-dimensional full-body kinematics and kinetics were collected when performing a spike jump before and after the fatigue protocol. Sagittal plane joint angles, joint work and patellar tendon loading were calculated and analyzed with curve analyses using paired sample t-tests to investigate fatigue effects (p < 0.05).

RESULTS

Fatigue induced a stiffer lower extremity landing strategy together with prolonged pelvis-trunk flexion compared to baseline (p = 0.001-0.005). Decreased patellar tendon forces (p = 0.001-0.010) and less eccentric knee joint work (-5%, p < 0.001) were observed after the fatigue protocol compared to baseline.

CONCLUSION

Protective strategies seem to be utilized in a fatigued state to avoid additional tensile forces acting on the patellar tendon, including proximal compensations and stiff lower extremity landings. We hypothesize that players might be more prone for developing PT if eccentric patellar tendon loads are high in the non-fatigued state and/or these loads are somehow not decreased after fatigue.

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.

Electromyographic activity of quadriceps muscles during eccentric squat exercises: implications for exercise selection in patellar tendinopathy

This study investigated the quadriceps muscle activity during eccentric squat exercises (ESE) with different decline angles and arcs of motion regarding the proper exercise selection for patellar tendinopathy management. Electromyographic activity of the rectus femoris, vastus lateralis, and vastus medialis obliquus (VMO) muscles was measured during ESE on 0°, 5°, 10°, 15°, and 20° decline in 20 recreationally active participants. The eccentric phase was divided into 0-30°, 30-60°, 60-90°, 0-60°, 30-90°, and 0-90° of knee flexion simultaneously via motion-analysis system. The analyses showed that there was a significant decline angle × arc interaction effect on electromyographic activity of all muscles during knee flexion movement. The main effect was found for the arc of motion of knee flexion, and the main effect for the decline angle also was present for each muscle, except for VMO. This study demonstrated that most selective quadriceps eccentric activation occurred during ESE performed on 20° decline throughout 60-90° of knee flexion.

The effectiveness of percutaneous ultrasound-guided needle tenotomy compared to alternative treatments for chronic tendinopathy: a systematic review

OBJECTIVES

To compare percutaneous ultrasound-guided needle tenotomy (PUNT) to alternative treatments for chronic tendinopathy.

MATERIALS AND METHODS

A systematic literature search was performed with the following combination of keywords: ultrasound-guided, percutaneous, needling, tenotomy, Tenex, tendinopathy, and fasciotomy. Original studies comparing PUNT to alternative treatments for chronic tendinopathy were included in this systematic review.

RESULTS

Twelve (n = 12) studies with 481 subjects were included. Two (2/12) articles compared PUNT to surgical tenotomy and concluded that PUNT provides the same outcomes as surgical tenotomy. Six (6/12) studies compared PUNT to platelet-rich plasma (PRP) injections, and two of them found both treatment modalities effective with no significant between-group differences. Three trials claimed that PUNT followed by PRP injections showed superior clinical outcomes compared to PUNT alone. However, the difference at long-term follow-up was statistically significant only in one of them. One study found PUNT superior to PUNT + PRP injection at short-term follow-up, although there were no between-group differences at long-term follow-up. Four (4/12) studies compared PUNT to steroid injection (SI) and showed that SI causes fast (2 weeks) but temporary pain relief, PUNT results in persistent but relatively slower improvement to SI, and the combined procedure has a more rapid and steady reduction in symptoms.

CONCLUSION

PUNT is an effective treatment technique for chronic tendinopathy and should be considered when non-invasive treatments have failed. Effects of PRP and SI are transient and dissipate over time and do not contribute to long-term outcome.

Efficacy of percutaneous electrolysis for the treatment of tendinopathies: A systematic review and meta-analysis

OBJECTIVE

To evaluate the efficacy of percutaneous electrolysis for the treatment of patients with tendinopathies.

DATA SOURCES

A systematic search of publications was conducted in Pubmed, Cinahl, Medline, Scopus and Web of Science.

METHODS

The Oxford 2011 Levels of Evidence and the Jadad scale were used to assess the quality of studies. The mean and standard deviation were obtained for each study group and used to calculate the effect size. The DerSimonian and Laird method was used to develop a random-effects model.

RESULTS

Of the 14 articles, four applied percutaneous electrolysis to the knee, three to the shoulder, three to the elbow, two to the hip and two to the ankle and foot. A meta-analysis on intensity of pain (evaluated with algometer and the Visual Analogue Scale) was performed on studies comparing percutaneous electrolysis with a control group, indicating that the groups treated with percutaneous electrolysis had better results (p = 0.01). Although percutaneous electrolysis did not overcome the analgesic effect achieved by corticosteroid injections.

CONCLUSIONS

The percutaneous electrolysis is effective for the treatment of tendinopathies. The combination of this technique with eccentric training has proven to be one of the most effective treatments to date for improving pain. PROSPERO Registration: CRD42021230005.

Association between Body Weight and Body Mass Index and Patellar Tendinopathy in Elite Basketball and Volleyball Players, a Systematic Review and Meta-Analysis

The features of Patellar-Tendinopathy are (1): pain localised to the inferior pole of the patellar; (2): the presence of load-related pain. Body-Weight and Body-Mass-Index, as two easily-measured variables, could potentially aid the prediction of PT. This review aims to establish relationships between Body-Weight and Body-Mass-Index and Patellar-Tendinopathy via synthesising the evidence from prospective-cohort and cross-sectional studies in elite basketball and volleyball players. Seven databases (PubMed, EMBASE, CINAHL, Google Scholar, Health-Management-Information-Consortium, National-Technical-Information-Service, ClinicalTrial.gov) and citation chasing were used to identify English peer-review articles from 2000 to 2022. An adapted version of the Newcastle-Ottawa scale was used for critical appraisal. Two reviewers were involved in literature searching, data extraction, and quality review. Two prospective cohort and five cross-sectional studies met the inclusion criteria, providing 849 subjects (male:female: 436:413). Five studies found BW is associated with PT. Three studies found a relationship between BMI and PT. Six out of seven studies were classified as very good studies. All studies were level IV evidence. The very low certainty evidence suggests an association between BW and PT. There is moderate certainty evidence that BMI is associated with PT. These preliminary findings should be treated cautiously due to the lack of strong evidence.

Shear-Wave Elastography of Patellar Ligament and Achilles Tendon in Semiprofessional Athletes: Comparing With Nonexercising Individuals

OBJECTIVES

To compare semiprofessional athletes and nonexercising individuals in terms of p-SWE properties of the patellar ligament and the Achilles tendon.

METHODS

This case-control study was conducted in University of Health Sciences, Haseki Education and Research Hospital. A total of 58 individuals, with 29 in each group (according to power analysis), were included in the study. All relevant findings, including demographic characteristics, body mass index (BMI), and exercise (km run per week, km/w) were recorded. The MyLab 9 (Esaote, Genova, Italy) device was used for SWE. The QElaXto-p-SWE software was utilized for P-SWE interpretation and analyses.

RESULTS

The mean age was 47.21 ± 12.16 years (range 22-70). Weight (P = .001) and BMI (P < .001) values were significantly higher in the nonathlete group than in the athlete group. There were no significant differences between groups in terms of age, gender, and height. Median SWE values of bilateral patellar ligaments (P < .001 and P < .001) and bilateral Achilles tendons (P < .001 and P < .001) were significantly higher in the athlete group than in the nonathlete group.

CONCLUSIONS

We revealed normal p-SWE characteristics for the patellar ligament and Achilles tendon, which are frequently injured in athletes. These scores are important in early detection and follow-up of injuries in athletes.

Reduced Vastus Medialis/Lateralis EMG Ratio in Volleyballers with Chronic Knee Pain on Sports-Specific Surfaces: A Pilot Study

BACKGROUND

Even though chronic knee pain is common in volleyball, neuromuscular imbalance as a potential risk factor has not been investigated in volleyball-specific tasks. The aim of the study was to compare neuromuscular control between healthy and injured players in a clinical jump test and a volleyball-specific jump task in real field conditions.

METHODS

Six athletes with knee pain and nine controls were included. Surface electromyographic data were recorded from the mm. vastus medialis (VM) and lateralis (VL) of both legs. VM/VL activation ratio was calculated from countermovement jump (CMJ) and volleyball spike indoors and on two beach surfaces.

RESULTS

All subjects had pain in the leading leg. Mann-Whitney U Test (M-W-U Test) revealed a significantly lower VM/VL ratio of the leading leg (always affected) of the injured compared with that of the healthy control group for the CMJ and spike jump on all three grounds. Bland-Altman analysis revealed low bias and low difference in standard deviation for the injured leg but high values for the uninvolved leg and healthy controls between tasks and grounds. These results could indicate that neuromuscular control might not adapt too well to different movement tasks and grounds in the injured leg.

CONCLUSION

Athletes with chronic knee pain might have lower VM/VL ratios than controls independent from movement task and ground. Neuromuscular control in injured athletes might be less adaptable to new circumstances. The results of neuromuscular control in laboratory settings might be applicable to field conditions in injured legs but not healthy ones.

Prevalence, patterns and factors associated with injury: comparison between elite Malaysian able-bodied and para-badminton players

OBJECTIVES

This study aimed to determine and compare the prevalence, patterns and factors associated with injury between elite Malaysian able-bodied and para-badminton players.

METHODS

Medical records from July 2007 to December 2017 were reviewed.

RESULTS

Among 209 able-bodied players, 1010 injuries were reported. The injuries affected the lower limb (67.2%), sustained during training (94.2%), overuse in nature (38.7%), and involving mostly junior players (62.4%). The injury rate was 94/year, lower than previously reported. Patellar tendinopathy and muscle strain to the upper limb and torso were the commonest. Age, sex and history of injury were predictors of injury. Lower limb injury was a predictor of upper limb and torso injuries, while history of injury to the upper limb and/or torso was a predictor of lower limb injury. Meanwhile, among 18 para-badminton players, 62 injuries were reported from July 2014 to December 2017, which involved the lower limb (45.2%), sustained during training (87.1%), overuse in nature (54.8%), and involved mostly standing-class players (77.8%). The injury rate was 10/year. Patellar tendinopathy, rotator cuff tendinopathy and back muscle strain were the commonest. The patterns of injury (site, occasion and nature) were similar between groups, except for the shoulder where nature was overuse in para-badminton players compared to acute in able-bodied players.

CONCLUSIONS

All players are susceptible to training-related injuries, particularly to the lower limb. Over the last decade, an increase in the injury index for the lower limb and a shift from chronic to acute for the upper limb were observed among able-bodied players. Age, sex and history of injury expose able-bodied players to greater risk. Meanwhile, for para-badminton players, overuse shoulder and knee injuries are commonest. These findings necessitate a comprehensive injury prevention program that encompasses all body regions with an emphasis on the lower limb among elite Malaysian able-bodied and para-badminton players.

Ultrasound imaging of patellar tendon thickness in elite sprint track cyclists and elite soccer players: An intra-rater and inter-rater reliability study

The goal of our study was to investigate the relative and absolute intra-rater and inter-rater reliability of ultrasound assessment of patellar tendon (PT) thickness assessed over four locations, in track cyclists and soccer players. Fifteen male elite track cyclists and 15 male elite soccer players participated. Tendon thickness was measured over 4 locations placed at 5-10-15-20 mm inferior to the apex of the patella by two experienced examiners. Each examiner took two US images for the test measurements with a 10-min rest period. After a 30-min period, the subjects underwent a retest measurements that were also repeated 1-week after. A two-way analysis of variance revealed a significant group x location interaction on PT thickness for Examiner 1 (p = .001, η² = .81) and Examiner 2 (p = 0.001, η² = 0.78). Intra-rater reliability ranged from good to excellent (ICC_2,k ≥ 0.75), whereas inter-rater reliability was good (ICC_2,k ≥ 0.75) in both groups. Ultrasonographic assessment of PT was found to be a reliable method to assess tendon thickness. The middle location of the PT (corresponding to 15 and 20 mm) can be considered the most reliable spot to measure PT thickness. The PT thickness was larger among track cyclists than soccer players, with larger differences over the distal location (15 mm). Ultrasonographic assessment of PT was found to be a reliable method to assess tendon thickness. The middle location of the PT corresponding to 15 mm and 20 mm can be considered the most reliable area to measure PT thickness.

Nearly half of patients with chronic tendinopathy may have a neuropathic pain component, with significant differences seen between different tendon sites: a prospective cohort of more than 300 patients

Objectives

Identifying the prevalence of neuropathic pain components in patients with chronic tendinopathy conditions using the Self-Administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) questionnaire.

Methods

Patients with chronic tendinopathy and ‘tendon-like’ conditions treated within a single hospital outpatient clinic specialising in tendinopathy were identified. Pain scores, plus global function patient-reported outcome measures (5-Level version of EuroQol-5 Dimension and Musculoskeletal Health Questionnaire (MSK-HQ)), were completed and compared with the S-LANSS questionnaire

Results

341 suitable patients with chronic tendinopathy and potentially similar conditions were identified. Numbers: lateral elbow tendinopathy (39), greater trochanteric pain syndrome (GTPS; 112), patellar tendinopathy (11), non-insertional Achilles tendinopathy (40), insertional Achilles tendinopathy (39), plantar fasciopathy (100). 68% were female, with a mean age of 54.0±11.3 years and a mean symptom duration of 38.1±33.7 months.

There was a mean S-LANSS score of 11.4±6.4. Overall, 47% of patients scored 12 or greater points on S-LANSS, indicating the possible presence of neuropathic pain. The highest proportion was in patients with plantar fasciopathy (61%), the lowest in those with GTPS (33%). Weak correlations were found between the S-LANSS score and MSK-HQ score, the numerical rating scale (0–10) values for ‘average pain’ and for ‘worst pain’, but not with the MSK-HQ %health value.

Conclusion

S-LANSS identified nearly half of patients with chronic tendinopathy as possibly having a neuropathic pain component. This is of unclear clinical significance but worth further study to see if/how this may relate to treatment outcomes. These results are from a single hospital clinic dealing with patients with chronic tendinopathy, without a control group or those with shorter symptom duration. However, this reinforces the probability of neuropathic pain components in at least some patients with chronic tendinopathy.

Case Report: Repeated Intralesional Injections of Autologous Mesenchymal Stem Cells Combined With Platelet-Rich Plasma for Superficial Digital Flexor Tendon Healing in a Show Jumping Horse

In the present case report a show jumping 10-year-old Sella Italiano gelding, presented with severe lameness, swelling and pain at palpation of the mid-metacarpal region of the left forelimb. Clinical and ultrasound examination diagnosed a chronic tendonitis of the central region of the superficial digital flexor tendon (SDFT). The lesion was a reoccurrence since it developed from a previously healed injury. The horse had to stop competing and was unresponsive to gold-standard treatments as Non-steroidal anti-inflammatory drugs (NSAIDs) and conservative management after 6 months of therapy. The animal was subjected to repeated intralesional injections of autologous adipose-derived mesenchymal stem cells (AD-MSCs) combined with autologous platelet-rich plasma (PRP). The combined treatment was administered twice in a 1-month interval. The healing process was assessed through clinical examination, ultrasound imaging and quantification of oxidative stress products and inflammatory mediators in blood plasma. After 2 weeks from first injection, a reduction of concentration of oxidative-derived products was observed, together with an increase of anti-inflammatory cytokines and pro-mitotic growth factors. These results were reflected clinically as the horse showed a reduction of lameness along with swelling and pain after 4 weeks. At the 1-year follow-up, the horse showed no signs of lameness and swelling. The ultrasonographic examination highlighted a compact fiber alignment with a normal echogenic tendon as observed in the sound contralateral limb. Moreover, the horse went back to the previous level of competition. Our results suggest the positive effects of a repeated intralesional injection of AD-MSCs and PRP for the treatment of a chronic tendonitis with long-term effects and an improvement for both equine quality of life and athletic performance.

Effects of β-Hydroxy β-Methylbutyric Supplementation in Combination with Conservative Non-Invasive Treatments in Athletes with Patellar Tendinopathy: A Pilot Study

The aim of the present study was to analyze the effect of conservative non-invasive treatments based on eccentric training, stretching and extracorporeal shock wave therapy (ESWT) supplemented with β-Hydroxy β-methylbutyric (HMB) or placebo (PLAC) on body composition, pain and muscular function (jump ability, muscular power and muscular strength) in athletes with patellar tendinopathy (PT). In a double-blind randomized trial, 8 athletes (4 males and 4 females) performed a physical rehabilitation for 4 weeks. They were randomly divided into two experimental groups (two males and two females in each one) that ingested HMB (HMBG) or PLAC (PLACG). In pre- and post-intervention were assessed body composition, pain, countermovement jump (CMJ), back-squat (BS) for analyzing peak power (W) (PPPP), load (kg) associated to PPPP (PPKG) and mean velocity (m/s) (PPMV) in addition to a 5-RM leg extension tests. An interaction intervention·supplementation (p = 0.049; Ƞ2p = 0.774) was observed in the height reached in the CMJ as an intervention effect in PPPP detected for the HMBG (p = 0.049). In addition, an enhancement in PPKG (p = 0.028; Ƞ2p = 0.842) was detected in the intervention, but not in PPMV, as an increase in the intervention in the 5-RM test (p = 0.001; Ƞ2p = 0.981) was observed. No changes were noted on body composition or pain (p > 0.05). The combination of eccentric training with stretching and ESWT increased concentric muscular power and strength after 4 weeks without changes in body lean mass or pain. In addition, HMB supplementation could enhance the power muscular performance in athletes with PT, optimizing the intervention adaptions.

Smart Device for Biologically Enhanced Functional Regeneration of Osteo-Tendon Interface

The spontaneous healing of a tendon laceration results in the formation of scar tissue, which has lower functionality than the original tissue. Moreover, chronic non-healing tendon injuries frequently require surgical treatment. Several types of scaffolds have been developed using the tissue engineering approach, to complement surgical procedures and to enhance the healing process at the injured site. In this work, an electrospun hybrid tubular scaffold was designed to mimic tissue fibrous arrangement and extracellular matrix (ECM) composition, and to be extemporaneously loaded into the inner cavity with human platelet lysate (PL), with the aim of leading to complete post-surgery functional regeneration of the tissue for functional regeneration of the osteo-tendon interface. For this purpose, pullulan (P)/chitosan (CH) based polymer solutions were enriched with hydroxyapatite nanoparticles (HP) and electrospun. The nanofibers were collected vertically along the length of the scaffold to mimic the fascicle direction of the tendon tissue. The scaffold obtained showed tendon-like mechanical performance, depending on HP content and tube size. The PL proteins were able to cross the scaffold wall, and in vitro studies have demonstrated that tenocytes and osteoblasts are able to adhere to and proliferate onto the scaffold in the presence of PL; moreover, they were also able to produce either collagen or sialoproteins, respectively-important components of ECM. These results suggest that HP and PL have a synergic effect, endorsing PL-loaded HP-doped aligned tubular scaffolds as an effective strategy to support new tissue formation in tendon-to-bone interface regeneration.

Effect of Eriocitrin on Cell Proliferation, Apoptosis, Migration, and Scar Formation-Related Genes Expression in Tendon Stem Cells

Tendinopathy is a common disease in elite and recreational athletes, and Eriocitrin is a flavonoid compound, which has antioxidant properties. The present study was undertaken to investigate the effect of Eriocitrin on tendon stem cells in vitro. Different concentrations of Eriocitrin (0, 25, 50, 75 µM) were used to treat tendon stem cells, cell proliferation was determined by CCK8 assay, apoptosis was detected by propidium iodide (PI) staining assays and caspase-3 activity assessment, wound-healing assaywas selected to detect the migration, and RT-PCR was chosen to detect the expression levels of scar formation-related gene markers (COMP, Fibronectin, and Biglycan). Eriocitrin treatment promoted cell proliferation of tendon stem cells in dose-dependent manner, and it reduced the apoptotic activities and improved the migration of tendon stem cells. It inhibited COMP, Biglycan, and Fibronectin expression. In summary, eriocitrin promoted cell proliferation of tendon stem cells, improved the migration of tendon stem cells, and inhibited the expression levels of some scar formation-related gene markers.

Efficacy of Extracorporeal Pulse-Activated Therapy in the Management of Lower-Extremity Running-Related Injuries: Findings From a Large Case Cohort

Running is one of the most popular sports worldwide, with many health benefits. Injuries are also common, with running-related injuries reported in up to 79% of runners annually. Extracorporeal shockwave treatment can be used to treat soft tissue conditions, with the strongest level of evidence for management of plantar fasciitis. However, most studies have focused on nonathletes or studied a single condition, and few investigations have reported outcomes for extracorporeal pulse-activated therapy. In this case series, we evaluated the outcomes of 94 runners receiving extracorporeal pulse-activated therapy for lower-extremity running-related injuries, including plantar fasciitis and lower-extremity tendinopathy (Achilles, posterior tibialis, patellar, hamstring). We hypothesized that most runners with foot and ankle injuries would respond favorably to treatment and that success rates would be similar across conditions. Overall, 74 runners (79%) met their respective minimal clinically important difference for functional outcome measures, with no differences in response by age, sex, body mass index, or chronicity of condition. Further, no differences were noted in proportion achieving the minimal clinically important difference between foot and ankle (Achilles, posterior tibialis, and plantar fascia) compared with proximal injuries (53 [84.3%] versus 31 [72%], p = .15). A mean of 4 treatments resulted in achieving the minimal clinically important difference, with 95% achieving it by 5 treatments. No differences in bars of pressure, frequency, or other aspects of treatments were observed to predict response. Our findings suggest that a majority of runners with lower-extremity injuries respond favorably to extracorporeal pulse-activated therapy, including those with foot and ankle injuries.

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.

Generalizability of Eccentric Exercise for Patients with Subacromial Pain Syndrome to Real-world Clinical Practice: A Propensity Score-based Analysis

Objectives:

Subacromial pain syndrome is a common problem in primary care. Although several randomized controlled trials have shown that eccentric exercise is effective in patients with subacromial pain syndrome, its generalizability to real-world clinical practice is unknown. This study aimed to investigate, using propensity score analysis, the generalizability of eccentric exercise for patients with subacromial pain syndrome to real-world daily clinical practice.

Methods:

In this study, 78 patients underwent eccentric exercise in addition to traditional exercise, and 77 patients underwent only traditional exercise for 4 weeks. Outcomes measured using a visual analog scale (VAS) and American Shoulder and Elbow Surgeons Society Standardized Shoulder Assessment Form (ASES) scores were assessed at baseline and at 4 weeks.

Results:

In the propensity score-matched analysis, 65 patients in each group were successfully matched (130 of 155 patients, 84% overall). After 4 weeks of exercise, pain intensity was lower in the eccentric exercise group than in the traditional exercise group (VAS −14.5, 95% CI −21.2 to −7.9, P<0.001). No significant difference in the improvement in function was found between the two groups (ASES 4.1, 95% CI −2.0 to 10.2, P=0.18).

Conclusions:

Eccentric and traditional exercise in combination could reduce pain in patients with subacromial pain syndrome to a greater extent than traditional exercise alone. These findings have clinical relevance to primary care practitioners who provide conservative treatment for patients with subacromial pain syndrome.

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.

Innovative Strategies in Tendon Tissue Engineering

The tendon is a highly aligned connective tissue that transmits force from muscle to bone. Each year, more than 32 million tendon injuries have been reported, in fact, tendinopathies represent at least 50% of all sports injuries, and their incidence rates have increased in recent decades due to the aging population. Current clinical grafts used in tendon treatment are subject to several restrictions and there is a significant demand for alternative engineered tissue. For this reason, innovative strategies need to be explored. Tendon replacement and regeneration are complex since scaffolds need to guarantee an adequate hierarchical structured morphology and mechanical properties to stand the load. Moreover, to guide cell proliferation and growth, scaffolds should provide a fibrous network that mimics the collagen arrangement of the extracellular matrix in the tendons. This review focuses on tendon repair and regeneration. Particular attention has been devoted to the innovative approaches in tissue engineering. Advanced manufacturing techniques, such as electrospinning, soft lithography, and three-dimensional (3D) printing, have been described. Furthermore, biological augmentation has been considered, as an emerging strategy with great therapeutic potential.

IN-SEASON REHABILITATION PROGRAM USING BLOOD FLOW RESTRICTION THERAPY FOR TWO DECATHLETES WITH PATELLAR TENDINOPATHY: A CASE REPORT

Background and Purpose

Patellar tendinopathy is an overuse injury experienced primarily by athletes; especially athletes who participate in sports that involve frequent jumping. Therapeutic exercise is the primary conservative treatment for patients with this condition. However, some patients with patellar tendinopathy may be unable to tolerate the loading that occurs during exercise. The use of blood flow restriction (BFR) therapy for patients with patellar tendinopathy may allow the athlete to exercise with a lower load while still experiencing the physiological benefits associated with training at a higher intensity. The purpose of this case report was to detail the outcomes from a rehabilitation program utilizing BFR for two collegiate decathletes with patellar tendinopathy.

Study Design

Case ReportCase Descriptions and Interventions: Two NCAA Division III freshmen collegiate decathletes with a history of left knee pain prior to college and who had been complaining of increasing pain during the initial month of track practices. Findings from the musculoskeletal examinations included left sided lower extremity weakness, pain during functional testing, pain when palpating the left patellar tendon, and VISA-P scores less than 80. Ultrasound imaging at baseline revealed thickened tendons on the left with hypoechoic regions. Both athletes participated in 20 therapy sessions consisting of therapeutic exercises performed with BFR.

Outcomes

Both athletes experienced improvements in pain scores, increases in lower extremity strength, improved functional test performance, higher VISA-P scores, and improvements in tendon size and appearance as measured by diagnostic ultrasound.

Conclusion

Both athletes experienced improvements with the BFR-based therapeutic exercise program and were able to compete throughout the track season. The use of BFR may allow patients who are unable to tolerate exercise due to pain an alternative approach during rehabilitation. Future research should compare therapeutic exercise programs for this condition with and without BFR.

Level of Evidence

Level V.

A biomechanical analysis of 3D stress and strain patterns in patellar tendon during knee flexion

Patellar tendinopathy is among the most widespread patellar tendon diseases in athletes that participate in activities involving running and jumping. Although their symptoms can be detected, especially at the inferior pole of the patella, their biomechanical cause remains unknown. In this study, a three-dimensional finite element model of knee complex was developed to investigate principal stress and strain distributions in the patellar tendon during 0° to 90° knee flexion and slow and fast level-ground walking. Results indicate that the patellar tendon is subjected to tensile stress and strains during all three activities. During flexion, its central proximal posterior region exhibited highest peak stress and strain, followed by central distal posterior, central distal anterior and central proximal anterior region. Similar trends and magnitudes were reported during slow and fast walking. The region with highest principal stresses and strains, central proximal anterior region, also corresponds to the most commonly reported patellar tendinopathy lesion site, suggesting that principal stress and strain are good indicators of lesion site location. Additional factors such as regional variations in material properties and frequency and duration of cyclic loading also need to be considered when determining the biomechanical aetiology of patellar tendinopathy.

A new method for estimating three-dimensional movement of the patella using a surface mapping method and computed tomography

Introduction

A previous study reported a method called the 2D-3D registration technique to examine three-dimensional movement of the patella. However, that method requires a biplane fluoroscopy system. In the present study, the aim was to establish a new method (CT-based surface mapping method) to estimate three-dimensional positions and angles of the patella with a motion capture system and CT.

Methods

In Study 1, the most appropriate parameters for the CT-based surface mapping method (i.e., target edge length, threshold of thickness of the soft tissue, and minimum distance between markers) were explored and determined. In Study 2, three-dimensional movement (i.e., positions and angles) of the patella using the CT-based surface mapping method and the most appropriate parameters were determined, and they were compared with the true positions and angles obtained by CT.

Results

The results of Study 1 showed that the most appropriate conditions were as follows: (1) target edge length, 3 mm; (2) threshold of thickness of the soft tissue, 0–20 mm; and (3) minimum distance between markers, 10 mm. The results of Study 2 showed that the errors of the positions and angles were less than approximately 10 mm and 10° at most, respectively (both supine and sitting positions).

Conclusion

The CT-based surface mapping method may be useful for a future study to clarify differences in three-dimensional movements of the patella between patients with patellar tendinitis and healthy subjects.

Thermal profiles over the Patella tendon in a cohort of non-injured collegiate athletes over the course of a cross-country season

OBJECTIVES

To determine normal temperatures over the Patella tendon over eleven weeks.

DESIGN

A prospective cohort study with eleven weeks of observation.

SETTING

University's Human Biomechanics and Physiology Laboratory.

PARTICIPANTS

Male or female collegiate runners running at least 25 miles per week who did not report pain in the region of the Patella tendon over 11 weeks of data collection.

MAIN OUTCOME MEASURES

Thermal images taken at the same time and day of the week, were used to measure the temperature of the skin over the Patella tendon.

RESULTS

Eighteen athletes were eligible for analysis. The mean temperature of the Patella tendon was 30.13 °C (SD = 1.51 °C). Patella tendon temperature changes over time were insignificant (right p = 0.66, left p = 0.90) with ICC right = 0.92, left = 0.94. Mean temperature difference side to side was 0.14 °C (SD = 0.60 °C). Mixed-model Linear regression for mean temperature differences found the effect of (i) time (t = 0.39, p = 0.70, df = 361) and (ii) side (t = -0.89, p = 0.38, df = 361) to be insignificant.

CONCLUSIONS

This is the first report of normal thermal profiles of collegiate runners over an extended period. Temperature variation above 1.20 °C may represent an abnormal asymmetry in the running population. Variations in Patella tendon temperatures left to right, and over time were not significant.

Bilateral changes in tendon structure of patients diagnosed with unilateral insertional or midportion achilles tendinopathy or patellar tendinopathy

PURPOSE

Changes in tendon structure are commonly seen in patients with unilateral achilles (AT) or patellar (PT) tendinopathy but might also be present on the asymptomatic side, indicating a higher risk for developing symptoms. The aim of this study is to compare tendon structure of the symptomatic side with the asymptomatic side in AT and PT patients and control subjects.

METHODS

A total of 46 patients with unilateral AT (16 insertional and 30 midportion) and 38 with unilateral PT were included. For the control group, a total of 18 Achilles tendons and 25 patellar tendons were scanned. Tendon structure was assessed using ultrasound tissue characterisation (UTC), which quantifies tendon organisation dividing the structure into four different echo types (I-IV).

RESULTS

There were significant differences in echo types I, III, and IV between symptomatic and asymptomatic sides and controls. Additionally, there was a significant difference between the symptomatic and the asymptomatic side for all tendinopathy locations. In the insertional AT tendon portion, the symptomatic side showed a higher percentage of echo type III. For the midportion AT, the symptomatic side showed a lower percentage of echo type I and a higher percentage of echo types III and IV. For the patellar tendon, the symptomatic side showed a higher percentage of echo types III and IV. All differences were higher than the minimal detectable changes.

CONCLUSION

Although patients have symptoms unilaterally, the tendon structures are compromised on both sides. These results stress the importance of monitoring both symptomatic and asymptomatic tendon structures and in addition highlight that the asymptomatic side should not be used as reference in clinical practice.

LEVEL OF EVIDENCE

III.

Thirty-seven jump-landing biomechanical variables are associated with asymptomatic patellar tendon abnormality and patellar tendinopathy: A systematic review

OBJECTIVE

To identify studies that report three-dimensional (3D) biomechanical analysis of jump-landing tasks in relation to athletes with current patellar tendinopathy (PT), and/or asymptomatic with history of PT or patellar tendon abnormality (PTA) on diagnostic imaging.

METHODS

Five electronic databases were searched. Included articles were required to: (1) investigate the 3D biomechanics of a jump-landing task; (2) be cross-sectional or longitudinal in design; and (3) include participants that had symptomatic PT, were asymptomatic with a history of PT, asymptomatic with PTA on diagnostic imaging and/or asymptomatic with an unknown pathology or PT history.

RESULTS

Thirty-seven statistically significant jump-landing variables were associated with PT, history of PT and/or PTA. The only consistent variable that could be replicated between studies was knee flexion angle at initial foot-ground contact (IC) and an altered hip flexion/extension strategy during a horizontal land phase of a vertical stop-jump.

CONCLUSION

Isolated vertical landings or take-offs alone may not be sensitive enough to identify key jump-landing variables associated with PT, thus clinicians and researchers should incorporate a whole jump-landing task with a horizontal landing component. Sagital plane hip and knee kinematics in a horizontal landing phase appear to provide the most valuable information for evaluating those with PT.

Rethinking Patellar Tendinopathy and Partial Patellar Tendon Tears: A Novel Classification System

BACKGROUND

Patellar tendinopathy is an overuse injury of the patellar tendon frequently affecting athletes involved in jumping sports. The tendinopathy may progress to partial patellar tendon tears (PPTTs). Current classifications of patellar tendinopathy are based on symptoms and do not provide satisfactory evidence-based treatment guidelines.

PURPOSE

To define the relationship between PPTT characteristics and treatment guidelines, as well as to develop a magnetic resonance imaging (MRI)-based classification system for partial patellar tendon injuries.

STUDY DESIGN

Cohort study (prognosis); Level of evidence, 2.

METHODS

MRI characteristics and clinical treatment outcomes were retrospectively reviewed for 85 patients with patellar tendinopathy, as well as 86 physically active control participants who underwent MRI of the knee for other conditions. A total of 56 patients had a PPTT and underwent further evaluation for tear size and location. The relationship between tear characteristics and clinical outcome was defined with use of statistical comparisons and univariate and logistic regression models.

RESULTS

Of the 85 patients, 56 had partial-thickness patellar tendon tears. Of these tears, 91% involved the posterior and posteromedial regions of the proximal tendon. On axial MRI views, patients with a partial tear had a mean tendon thickness of 10 mm, as compared with 6.2 mm for those without (P < .001). Eleven patients underwent surgery for their partial-thickness tear. All of these patients had a tear >50% of tendon thickness (median thickness of tear, 10.3 mm) on axial views. Logistic regression showed that tendon thickness >8.8 mm correlated with the presence of a partial tear, while tendon thickness >11.45 mm and tear thickness >55.7% predicted surgical management.

CONCLUSION

Partial-thickness tears are located posterior or posteromedially in the proximal patellar tendon. The most sensitive predictor for detecting the presence of a partial tear was patellar tendon thickness, in which thickness >8.8 mm was strongly correlated with a tear of the tendon. Tracking thickness changes on axial MRI may predict the effectiveness of nonoperative therapy: athletes with patellar tendon thickness >11.5 mm and/or >50% tear thickness on axial MRI were less likely to improve with nonoperative treatment. A novel proposed classification system for partial tears, the Popkin-Golman classification, can be used to guide treatment decisions for these patients.

Low prevalence of patellar tendon abnormality and low incidence of patellar tendinopathy in female collegiate volleyball players

The prevalence of patellar tendinopathy has been reported to be as high as 50% in elite male volleyball (VB) players; however, the rate of injury in female collegiate VB athletes is unknown. The purpose of this study was to 1) identify the prevalence of ultrasonographic evidence of patellar tendon abnormality at the start of the preseason in female collegiate VB players; 2) report the incidence of tendinopathy during the season; and 3) determine if the preseason presence of tendon abnormality is associated with onset of disease. One hundred and six female collegiate VB players had both patellar tendons imaged. Incidence of patellar tendinopathy was tracked during the course of the 4-month season. Twenty-two athletes presented with ultrasonographic evidence of patellar tendon abnormality in at least one knee at the start of the preseason. The incidence of time-loss patellar tendinopathy was 0.26 (95% CI: 0.04, 0.85) per 1000 athletic exposures. This study was unable to determine if preseason presence of tendon abnormality was associated with a greater risk of tendinopathy due to power. The prevalence of tendon abnormality in the preseason and the incidence of patellar tendinopathy in female collegiate VB players are lower than that observed in other populations.

Prevalence of Patellar Tendinopathy and Patellar Tendon Abnormality in Male Collegiate Basketball Players: A Cross-Sectional Study

CONTEXT

Patellar tendinopathy (PT) is a degenerative condition known to affect athletes who participate in sports such as basketball and volleyball. Patellar tendinopathy is a challenging condition to treat and may cause an athlete to prematurely retire from sport. The prevalence of PT in male collegiate basketball players is unknown.

OBJECTIVE

To determine the prevalence of PT and patellar tendon abnormality (PTA) in a population of male collegiate basketball players.

DESIGN

Cross-sectional study.

SETTING

National Collegiate Athletic Association Divisions II and III, National Association of Intercollegiate Athletics, and Northwest Athletic Conference male collegiate basketball teams were assessed in a university laboratory setting.

PATIENTS OR OTHER PARTICIPANTS

Ninety-five male collegiate basketball players (age = 20.0 ± 1.7 years).

MAIN OUTCOME MEASURE(S)

A diagnostic ultrasound image of an athlete's patellar tendon was obtained from each knee. Patellar tendinopathy was identified based on a player's symptoms (pain with palpation) and the presence of a hypoechoic region on an ultrasonographic image.

RESULTS

A majority of participants, 53 of 95 (55.8%), did not present with pain during palpation or ultrasonographic evidence of PTA. Thirty-two basketball players (33.7%) displayed ultrasonographic evidence of PTA in at least 1 knee; 20 of those athletes (21.1%) had PT (pain and tendon abnormality). Nonstarters were 3.5 times more likely to present with PTA (odds ratio = 3.5, 95% confidence interval = 1.3, 9.6; P = .017) and 4 times more likely to present with PT (odds ratio = 4.0, 95% confidence interval = 1.1, 14.8; P = .038) at the start of the season.

CONCLUSIONS

One in 3 male collegiate basketball players presented with either PT or PTA. Sports medicine professionals should evaluate basketball athletes for PT and PTA as part of a preseason screening protocol.

Sesamoids in tetrapods: the origin of new skeletal morphologies

Along with supernumerary bones, sesamoids, defined as any organized intratendinous/intraligamentous structure, including those composed of fibrocartilage, adjacent to an articulation or joint, have been frequently considered as enigmatic structures associated with the joints of the skeletal system of vertebrates. This review allows us to propose a dynamic model to account for part of skeletal phenotypic diversity: during evolution, sesamoids can become displaced, attaching to and detaching from the long bone epiphyses and diaphysis. Epiphyses, apophyses and detached sesamoids are able to transform into each other, contributing to the phenotypic variability of the tetrapod skeleton. This dynamic model is a new paradigm to delineate the contribution of sesamoids to skeletal diversity. Herein, we first present a historical approach to the study of sesamoids, discussing the genetic versus epigenetic theories of their genesis and growth. Second, we construct a dynamic model. Third, we present a summary of literature on sesamoids of the main groups of tetrapods, including veterinary and human clinical contributions, which are the best-studied aspects of sesamoids in recent decades. Finally, we discuss the identity of certain structures that have been labelled as sesamoids despite insufficient formal testing of homology. We also propose a new definition to help the identification of sesamoids in general. This review is particularly timely, given the recent increasing interest and research activity into the developmental biology and mechanics of sesamoids. With this updated and integrative discussion, we hope to pave the way to improve the understanding of sesamoid biology and evolution.

The presence of patellar tendinopathy in the bone-patellar tendon-bone autograft may increase the risk of anterior cruciate ligament graft failure

PURPOSE

The purpose of this study was to evaluate the influence of patellar tendinopathy on primary anterior cruciate ligament (ACL) reconstruction graft failure when using bone-patellar tendon-bone (BPTB) autograft.

METHODS

All patients undergoing primary ACL reconstruction using ipsilateral BPTB with preoperative magnetic resonance imaging (MRI) available for review were approached for eligibility. The medical charts of included patients were reviewed to obtain demographic information, anatomical characteristics, injury characteristics, treatment characteristics, length of follow-up, and presence of graft failure. A single, fellowship-trained, knee-specialist and blinded researcher performed preoperative MRI interpretation of patellar tendinopathy. The presence/absence of patellar tendinopathy (none, mild, moderate, or severe changes) was compared between patients with (cases) and without (controls) failure of ACL reconstruction. There were 559 cases with a median (range) clinical follow-up was 8 (4-30) months and an average age of 21.5 years (82% males).

RESULTS

Of the 559 cases, there were 182 (32.6%) with and 377 (67.4%) without patellar tendinopathy. A total of 32 (5.7%) graft failures occurred. There were a significantly higher failure rate in patients with compared to without patellar tendinopathy (p < 0.001), and in patients with compared to without partial tendon tear (p < 0.001). The odds ratio (95% confidence interval) for graft failure was 5.9 (2.7-13.1), 20.8 (6.8-63.9) and 54.4 (5.5-539.4) in patients with patellar tendinopathy (compared to absence of patellar tendinopathy), moderate or severe patellar tendinopathy (compared to none or mild patellar tendinopathy), or partial tendon tear (compared to absence of tendon tear), respectively.

CONCLUSION

The presence of patellar tendinopathy increases the risk of BPTB graft failure when used for ACL reconstruction. The use of BPTB autograft is not recommended if patellar tendinopathy is obvious or there are suspicious of partial tendon tear on MRI. In such cases, the surgeon should consider using a different graft.

LEVEL OF EVIDENCE

Retrospective cohort analysis, Level III.

Immediate effect of infrapatellar strap on pain and jump height in patellar tendinopathy among young athletes

BACKGROUND:

Infrapatellar strapping is a treatment technique used in various knee pathologies; however, its effect on pain and functional performance among young athletes has not been studied.

OBJECTIVES:

To evaluate the effect of infrapatellar strap on pain and jumping performance among young athletes diagnosed with patellar tendinopathy.

STUDY DESIGN:

Pre-/post-test (within-subject research design).

METHODS:

A total of 16 young male basketball and volleyball athletes (age range, 12-18 years) diagnosed with patellar tendinopathy were included in the study. Infrapatellar strap was applied beneath the patella, over the patellar tendon. The athletes performed four jumping tests: squat jump, drop jump, single-leg jump, and jumps 30 s test, with and without the strap. Pain severity in the symptomatic knee during jumping was assessed using a visual analog scale and jumping performance parameters were assessed using an Optojump Next optical measurement system.

RESULTS:

Pain severity reported by the participants decreased in drop test, single-leg jump test, and jumps 30 s test while using the infrapatellar strap compared with no strap condition ( p < 0.05). No significant difference in jumping performance was found between jumping with and without the strap.

CONCLUSION:

The infrapatellar strap was effective in reducing local pain among young male athletes without altered jumping performance.

CLINICAL RELEVANCE

The infrapatellar strap can be recommended to use during physical activity as part of the physical therapy treatments for patellar tendinopathy. Given the low cost, ease to use, and being a non-invasive method without adverse effects, it is an appropriate intervention for young athletes.

Influence of loading rate and limb position on patellar tendon mechanical properties in vivo

BACKGROUND

The aims of this study were to clarify the changes of patellar tendon length during isometric knee joint extension and the double leg squat position using ultrasonography.

METHODS

The left legs of 17 healthy adults were investigated. Isometric knee extension motion was performed at three positions of knee flexion 30° (knee 30°), knee flexion 60° (knee 60°), knee flexion 90° (knee 90°), and at each limb position, 0% (0% peak torque (PT)), 40% (40% PT), 50% (50% PT), and 60% (60% PT) of the maximum knee joint extension torque were executed at random. Both double leg squat motions were randomly performed in three positions: hip flexion 30°, knee flexion 30°, ankle dorsiflexion 10° (squat 30°); hip joint flexion 60°, knee joint flexion 60°, ankle dorsiflexion 20° (squat 60°); and hip joint flexion 90°, knee joint flexion 90°, ankle dorsiflexion 30° (squat 90°). Ultrasonography was used to measure patellar tendon length.

FINDINGS

There were no significant changes in patellar tendon length and strain between knee flexion angles of 30°, 60°, and 90° in isometric knee joint extension and the double leg squat limb position.

INTERPRETATION

The loading rate and limb position do not appear to affect the length and strain of the patellar tendon.

Tenogenically differentiated adipose-derived stem cells are effective in Achilles tendon repair in vivo

The purpose of this study was to characterize rat adipose-derived stem cells, induce adipose-derived stem cell tenogenesis, and analyze adipose-derived stem cell effects on tendon repair in vivo. Adipose-derived stem cells demonstrated an immunomodulatory, pro-angiogenic, and pro-proliferatory profile in vitro. Tenogenesis was induced for 1, 7, 14, and 21 days with 24 combinations of growth differentiation factor-5, 6, and 7 and platelet-derived growth factor–BB. Adipose-derived stem cells expression of scleraxis and collagen type I increased the most after 14 days of induction with growth differentiation factor-6 and platelet-derived growth factor–BB. Achilles excision defects injected with hydrogel alone (Gp2), with undifferentiated (Gp3) adipose-derived stem cells, or tenogenically differentiated (Gp4) adipose-derived stem cells exhibited improved tissue repair compared with untreated tendons (Gp1). Addition of adipose-derived stem cells improved tissue cytoarchitecture and increased expression of collagen type I and III, scleraxis, and tenomodulin. Adipose-derived stem cells significantly improved biomechanical properties (ultimate load and elastic toughness) over time more than hydrogel alone, while tenogenically differentiated adipose-derived stem cells improved the mean histological score and collagen fiber dispersion range closest to normal tendon. In addition, tendon sections treated with GFP-adipose-derived stem cells exhibited green fluorescence and positive GFP immunostaining on microscopy confirming the in vivo survival of adipose-derived stem cells that were injected into tendon defects to support the effects of adipose-derived stem cells on tissue up to 4.5 weeks post injury.

Up to a quarter of patients with certain chronic recalcitrant tendinopathies may have central sensitisation: a prospective cohort of more than 300 patients

Introduction

To identify the possible prevalence of 'central sensitisation', in patients with chronic recalcitrant lower limb tendinopathy conditions, with the Central Sensitisation Inventory (CSI) questionnaire.

Methods

Patients with chronic lower limb tendinopathy conditions treated within a single hospital outpatient clinic specialising in tendinopathy were identified from clinical records. As part of routine care, self-reported numerical markers of pain, global function (using the EuroQol-5D (EQ-5D) questionnaire) and the CSI score to investigate the possibility of central sensitisation were completed.

Results

A total of 312 suitable patients with chronic lower limb tendinopathy and similar conditions were identified, who had completed a CSI questionnaire. Of these, 108 presented with greater trochanteric pain syndrome, 12 with patella tendinopathy, 33 with non-insertional Achilles tendinopathy, 48 with insertional Achilles tendinopathy and 110 with plantar fasciitis. A total of 66% of the patients were female, the median age was 54.9 years and the median duration of symptoms was 24 months. There was a median CSI score of 25%, with statistically significant differences noted between the different conditions studied. Overall, 20% of patients scored above a threshold of 40% on CSI questionnaire, indicating that central sensitisation was possible. Greater trochanteric pain syndrome and plantar fasciitis had the highest proportions in the conditions studied. Weak correlations were found between CSI and other pain scores studied.

Conclusion

The CSI questionnaire may identify up to a quarter of patients with some chronic lower limb tendinopathy and associated conditions as being more likely to have central sensitisation, and these proportions differed between conditions. The clinical significance of this is unclear, but worth further study to see if/how this may relate to treatment outcomes. These are results from a single hospital clinic dealing with patients with chronic tendinopathy, and comparison with a control group is currently lacking. However, on the information presented here, the concept of central sensitisation should be considered in patients being treated for chronic tendinopathy.

Effects of a strength protocol combined with electrical stimulation on patellar tendinopathy: 42 months retrospective follow-up on 6 high-level jumping athletes

STUDY DESIGN

A retrospective study.

INTRODUCTION

Patellar tendinopathy (PT) or jumper's knee (JK) in elite athletes is a challenging condition for sports medicine professionals. This study analyzes the development of a protocol using eccentric, isometric, concentric exercises, and electrostimulation to treat elite athletes suffering from JK. The semiannual strength protocol was completed during a total of 36 months by six high-level jumping athletes with chronic painful JK. Pain during patellar tendon loading activity was evaluated on a visual analogue pain scale (VAS). Upon protocol completion, promising clinical results were evidenced by significant pain reduction during tendon loading activity.

MATERIAL AND METHODS

Six high level jumping athletes with chronic painful JK completed a semiannual strength program using eccentric, isometric, concentric and electrical stimulation exercises. The protocol was done 12 weeks in the winter pre-season and 10 weeks in the summer pre-season, for altogether 36 months, with an interruption of the protocol at 24 months for 6 months. Pain during patellar tendon loading activity was evaluated on a visual analogue pain scale (VAS), before the first session and then every 6 months, coinciding with the competitive phase, the time of maximum pain.

RESULTS

There was a significant (p < 0.01) decrease in the VAS from start to the 18, 24 and 48 months follow-ups.

CONCLUSIONS

In a small group of high level jumping athletes with chronic painful JK, a strength protocol combined with electrical stimulation showed promising clinical results with significant pain reduction during tendon loading activity.

Ultrasound elastography: compression elastography and shear-wave elastography in the assessment of tendon injury

Ultrasound elastography (USE) is a recent technology that has experienced major developments in the past two decades. The assessment of the main mechanical properties of tissues can be made with this technology by characterisation of their response to stress. This article reviews the two major techniques used in musculoskeletal elastography, compression elastography (CE) and shear-wave elastography (SWE), and evaluates the studies published on major electronic databases that use both techniques in the context of tendon pathology. CE accounts for more studies than SWE. The mechanical properties of tendons, particularly their stiffness, may be altered in the presence of tendon injury. CE and SWE have already been used for the assessment of Achilles tendons, patellar tendon, quadriceps tendon, epicondylar tendons and rotator cuff tendons and muscles. Achilles tendinopathy is the most studied tendon injury with USE, including the postoperative period after surgical repair of Achilles rupture tendon. In relation to conventional ultrasound (US), USE potentially increases the sensitivity and diagnostic accuracy in tendinopathy, and can detect pathological changes before they are visible in conventional US imaging. Several technical limitations are recognised, and standardisation is necessary to ensure repeatability and comparability of the results when using these techniques. Still, USE is a promising technique under development and may be used not only to promote an early diagnosis, but also to identify the risk of injury and to support the evaluation of rehabilitation interventions. KEY POINTS: • USE is used for the assessment of the mechanical properties of tissues, including the tendons. • USE increases diagnostic performance when coupled to conventional US imaging modalities. • USE will be useful in early diagnosis, tracking outcomes and monitoring treatments of tendon injury. • Technical issues and lack of standardisation limits USE use in the assessment of tendon injury.

Imaging modalities in the diagnosis and monitoring of Achilles tendon ruptures: A systematic review

OBJECTIVE

To determine the role of imaging in the diagnosis and monitoring of the Achilles tendon rupture (ATR).

STUDY DESIGN

Systematic review.

DATA SOURCES

PubMed and EMBASE in November 2016.

ELIGIBILITY CRITERIA

Clinical studies providing information on the methods and role of imaging in the diagnosis and monitoring of the ATR were included.

RESULTS

Fifty-six studies were included, most concerning the use of ultrasound (n=37) or MRI (n=18). Seven studies provided data on the diagnostic accuracy of imaging. Most ultrasound studies used a 7.5MHz probe (19/32 studies) and scanned the patient bilaterally in prone position, with recent studies tending to use higher frequency probes (r=0.42). Sensitivity [for detecting a rupture] ranged from 79.6 to 100%; the spread in specificity was large but two studies showed perfect (100%) data. Negative and positive likelihood ratios ranged from 0 to 0.23 and 1.0 to 10 respectively. MRI examination was generally performed with 1.5Tesla (T) MRI (6/12 studies) with a strong trend for higher T strength in more recent studies (r=0.71). One study reported a sensitivity of 90.9% and one a specificity of 100%. Although imaging can visualize structure and healing, these results were generally not related to the clinical picture. Overall, ultrasound was recommended over MRI for diagnosis and monitoring. Results of other imaging modalities remain inconclusive.

CONCLUSION

The adjunct role of imaging, especially of ultrasound and MRI, in the diagnosis and monitoring of ATRs was established. It is therefore recommended to rely primarily on the clinical examination and evaluation and to use imaging for ruling out other injuries and providing additional clinical information. More high-quality research is warranted into the diagnostic accuracy of imaging as well as less conventional imaging modalities' diagnostic and monitoring capabilities.