Marked pathological changes proximal and distal to the site of rupture in acute Achilles tendon ruptures

A case report of Achilles tendon distractive rupture after shock wave therapy

The primary objective of this research essay is to critically examine the relationship between shock wave therapy usage and subsequent. Achilles tendon ruptures, with a specific focus on a case involving a 68-year-old patient with a history of Achilles tendinopathy, who experienced a perceptible pop and intense Achilles pain, after treatment with shock wave therapy. The assessment revealed typical rupture that was treated with surgical repair. By tracking the patient's medical history and various treatment methods employed, the study aims to clarify the complex link between therapeutic actions and potential risks. Additionally, the case report seeks to review current literature on the adverse effects of repeated micro-trauma from percussive ultrasound therapy, suggesting that an inadequate understanding of biomechanical principles may have contributed to the unexpected complications. Ultimately, the aim of the study is to raise awareness among clinicians about appropriate treatment protocols to ensure patient safety and optimal recovery outcomes.

Does free tendon length influence the injury risk of the Achilles tendon? A finite element study

Purpose

The Achilles tendon is a common injury site, but anatomical risk factors for injury are relatively unexplored in the literature. This study aimed to evaluate whether changes in free tendon length would influence the results of a simulated rupture of the Achilles tendon.

Methods

Using a previously validated 3D finite element model of the free and aponeurotic Achilles tendon as a basis, two additional finite element models with 25% decreased and increased free tendon lengths were created. The finite element models were sequentially loaded from 2500 to 3500N in 100N increments, and the total volume of elements exhibiting a maximal principal strain above 10% was recorded. An Achilles tendon rupture was considered to have occurred when a continuous group of elements with a volume of at least 3 mm3 exhibited a maximum principal strain above 10%. Models were compared regarding the smallest load that met the rupture criterion and plots of the percentage of elements exhibiting maximum principal strains above 10% across the loading range. Sensitivity analyses assessed the influence of subtendon division variations and subtendon sliding restriction on the results.

Results

Rupture loads and plots of the percentage of elements with maximum principal strains above 10% were similar between models, regardless of the free tendon length. No models met the rupture criterion when simulations were run without subtendon sliding. Rupture loads in the subtendon division variation models were correlated with the subtendon cross-sectional areas.

Conclusions

The simulated rupture results of the Achilles tendon were sensitive to variations in subtendon cross-sectional areas but not in free tendon length.

Level of Evidence

Level V.

Widespread Vascularization and Correlation of Glycosaminoglycan Accumulation to Tendon Pain in Human Plantar Fascia Tendinopathy

BACKGROUND

Plantar fasciitis is a painful tendinous condition (tendinopathy) with a high prevalence in athletes. While a healthy tendon has limited blood flow, ultrasound has indicated elevated blood flow in tendinopathy, but it is unknown if this is related to a de facto increase in the tendon vasculature. Likewise, an accumulation of glycosaminoglycans (GAGs) is observed in tendinopathy, but its relationship to clinical pain is unknown.

PURPOSE

To explore to what extent vascularization, inflammation, and fat infiltration were present in patients with plantar fasciitis and if they were related to clinical symptoms.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Biopsy specimens from tendinopathic plantar fascia tissue were obtained per-operatively from both the primary site of tendon pain and tissue swelling ("proximal") and a region that appeared macroscopically healthy at 1 to 2 cm away from the primary site ("distal") in 22 patients. Biopsy specimens were examined with immunofluorescence for markers of blood vessels, tissue cell density, fat infiltration, and macrophage level. In addition, pain during the first step in the morning (registered during an earlier study) was correlated with the content of collagen and GAGs in tissue.

RESULTS

High vascularization (and cellularity) was present in both the proximal (0.89%) and the distal (0.96%) plantar fascia samples, whereas inconsistent but not significantly different fat infiltration and macrophage levels were observed. The collagen content was similar in the 2 plantar fascia regions, whereas the GAG content was higher in the proximal region (3.2% in proximal and 2.8% in distal; P = .027). The GAG content in the proximal region was positively correlated with the subjective morning pain score in the patients with tendinopathy (n = 17).

CONCLUSION

In patients with plantar fasciitis, marked tissue vascularization was present in both the painful focal region and a neighboring nonsymptomatic area. In contrast, the accumulation of hydrophilic GAGs was greater in the symptomatic region and was positively correlated with increased clinical pain levels in daily life.

CLINICAL RELEVANCE

The accumulation of GAGs in tissue rather than the extent of vascularization appears to be linked with the clinical degree of pain symptoms of the disease.

Effectiveness of High-Power Laser Therapy via Shear Wave Speed Analysis on Pain and Functioning in Patients with Lateral Epicondylitis: A Proof-of-Concept Study

Background: Lateral epicondylitis (LE) causes lateral elbow pain due to the overuse of the common extensor tendon. Several therapies have been proposed for pain relief and functional recovery, including physical therapy, minimally invasive injection approaches, and physical agent modalities such as laser therapy. Methods: Our study evaluates the impact of high-power laser therapy (HPLT) on pain and functioning. The HPLT protocol consists of 10 daily sessions using a LASERIX PRO device. The healthy elbow of each participant was also considered as a control group. The outcomes assessed were the Numerical Rating Scale (NRS) for pain, QuickDASH questionnaire for functionality, and shear wave velocity (SWS) through ultrasonography. Assessments were conducted at baseline (T0), post-treatment (T1), and 2-week follow-up (T2). Results: Sixteen participants (81.2% male, mean age 40.4 ± 5.53 years) completed the study. Post-treatment, pain significantly decreased (NRS: T0 6.13 ± 0.96; T1 2.75 ± 1.69; p <  0.001), functionality improved (QuickDASH: T0 69.88 ± 10.75; T1 41.20 ± 3.78; p < 0.001), and shear wave velocity increased (SWS (m/s): T0 1.69 ± 0.35; T1 2.56 ± 0.36; p <  0.001). Conclusions: At the 2-week follow-up, pain relief was maintained, and shear wave velocity showed no further significant change. Shear wave velocity assessments might be considered a useful diagnostic tool. However, further research is needed to support the role of HPLT and shear wave velocity in the rehabilitation management of LE.

Overload in a Rat In Vivo Model of Synergist Ablation Induces Tendon Multiscale Structural and Functional Degeneration

Tendon degeneration is typically described as an overuse injury with little distinction made between magnitude of load (overload) and number of cycles (overuse). Further, in vivo, animal models of tendon degeneration are mostly overuse models, where tendon damage is caused by a high number of load cycles. As a result, there is a lack of knowledge of how isolated overload leads to degeneration in tendons. A surgical model of synergist ablation (SynAb) overloads the target tendon, plantaris, by ablating its synergist tendon, Achilles. The objective of this study was to evaluate the structural and functional changes that occur following overload of plantaris tendon in a rat SynAb model. Tendon cross-sectional area (CSA) and shape changes were evaluated by longitudinal MR imaging up to 8 weeks postsurgery. Tissue-scale structural changes were evaluated by semiquantified histology and second harmonic generation microscopy. Fibril level changes were evaluated with serial block face scanning electron microscopy (SBF-SEM). Functional changes were evaluated using tension tests at the tissue and microscale using a custom testing system allowing both video and microscopy imaging. At 8 weeks, overloaded plantaris tendons exhibited degenerative changes including increases in CSA, cell density, collagen damage area fraction (DAF), and fibril diameter, and decreases in collagen alignment, modulus, and yield stress. To interpret the differences between overload and overuse in tendon, we introduce a new framework for tendon remodeling and degeneration that differentiates between the inputs of overload and overuse. In summary, isolated overload induces multiscale degenerative structural and functional changes in plantaris tendon.

Global trends in research of achilles tendon injury/rupture: A bibliometric analysis, 2000–2021

Background

The Achilles tendon is the strongest and most susceptible tendon in humans. Achilles tendon injuries and ruptures have gradually attracted research attention. However, a bibliometric analysis of global research in this field is lacking. This study involved a bibliometric analysis of the developmental trends and research hotspots in Achilles tendon injuries/ruptures from 2000 to 2021.

Methods

Articles published between 2001 and 2021 were retrieved from an extended database of the Science Citation Index using Web of Science. VOSviewer and CiteSpace were used to analyze the relationships between publications, countries, institutions, journals, authors, references, and keywords.

Results

This study included 3,505 studies of 73 countries, 3,274 institutions, and 12,298 authors and explored the cooperation between them and the relationships between citations. Over the past 22 years, the number of publications has significantly increased. Foot Ankle International has published the most papers on Achilles tendon injuries/ruptures, and British Journal of Sports Medicine is the most famous journal. Re-rupture, exosomes, acute Achilles tendon rupture, and tendon adhesions gradually become the research focus over the past few years.

Conclusion

Achilles tendon injury and rupture are important research topics. A vast number of newly published papers on this topic have demonstrated that clinicians and researchers are interested in their study. Over time, these recent studies will be widely cited; therefore, this bibliometric analysis should be constantly updated.

Synthetic Graft Augmentation Is Safe and Effective for the Repair of Acute Achilles Tendon Rupture in Patients With Preexisting Tendinopathy

Purpose

To assess the safety and report the clinical outcomes of synthetic graft augmentation using polypropylene (PP) mesh in the repair of acute Achilles tendon (AT) rupture in patients with preexisting tendinopathy. Methods: Patients who underwent open repair for acute AT rupture at our institution between April 2017 and March 2019 were retrospectively identified. The inclusion criteria were acute AT rupture in patients with preexisting tendinopathy. All patients included in the study underwent acute repair augmented by an inlay PP mesh and had 30 months' follow-up. Patient characteristics, operative details, and outcomes were analyzed. Continuous data were described by mean, standard deviation, median, and range. The Wilcoxon signed rank test was used to analyze the change in patient-reported outcome measures. The significance level was set at a P-value of .05.

Results

Thirteen patients were included. There were 5 female and 8 male patients, withan average age of 52 years (range 49-56 years). No cases of rerupture or graft-related complications requiring additional treatment occurred during mean follow -up of 38 months. All patients reported good functional outcome, as shown from nonsignificant difference between the preinjury and 38-month postoperative Achilles Tendon Rupture Score (88.5 ± 2.2 vs 89.2 ± 2.2, P = .107) and the excellent postoperative American Orthopedic Foot and Ankle Society Ankle/Hindfoot Scale score (92.22 ± 2.2) at last follow-up. At the end of follow-up, all patients were able to perform single-legged heel rise as the noninvolved side. By average of 16 weeks, all patients returned to their preinjury activity level.

Conclusions

The use of inlay PP mesh to augment the repair of acute AT rupture in patients with preexisting tendinopathy appears to be safe and effective, allowing early return to preinjury activity level with favorable clinical outcomes.

Level of Evidence

Level IV, therapeutic case series.

Trends in hospitalization for paediatric flatfoot: an Italian nationwide study from 2001 to 2016

Background

Flatfoot is a common condition in young patients, but usually resolves by adolescence. This study aimed to estimate annual trend hospitalizations for flatfoot in Italian paediatric population from 2001 to 2016.

Methods

Data of this study were collected from the National Hospital Discharge Reports (SDO) reported at the Italian Ministry of Health regarding the years of this paper (2001–2016). The yearly number of hospital admission for flatfoot, the percentage of males and females, the average age, the average days of hospitalization, primary diagnoses and primary procedures in the whole Italian population were calculated using descriptive statistical analyses.

Results

109,300 hospitalizations for flatfoot of young patients were performed during this period. 59.3% of patients were male and 40.7% female of the 10–14 years-old age class. The average days of hospitalization stay were 1.73 ± 1.27 days. The data highlights that the burden of flatfoot surgery is growing and affecting the healthcare system. The mean rate of hospital admissions in Italy for flatfoot in the young population was 82.14 for 100,000 inhabitants of the same age class.

Conclusions

The data highlights that the cases of flatfoot surgery increased from 2001 to 2016. The most common treatment was the “Internal Fixation Of Bone Without Fracture Reduction, Tarsals And Metatarsals followed by Subtalar Fusion and Arthroereisis. Further prospective studies on this topic may be conducted to improve the evidence of the results.

Performance Outcomes After Surgical Repair of Achilles Tendon Rupture in the Women's National Basketball Association

Background:

Achilles tendon ruptures are devastating in elite athletes. There are currently no studies examining the effects of Achilles tendon rupture on performance outcomes in the Women’s National Basketball Association (WNBA).

Hypothesis:

Athletes in the WNBA who sustained an Achilles tendon rupture and underwent subsequent surgical repair will sustain declines in performance metrics when compared with their preinjury statistics and matched controls.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Seventeen WNBA players who sustained an Achilles tendon rupture from 2000 to 2019 were identified through publicly available injury reports and player profiles. Athlete information collected included age, body mass index, position, and service in the WNBA when the tear occurred. Statistics were collected for 1 season before and 2 seasons after the injury, and the player efficiency rating (PER) was calculated. Players were matched to uninjured controls by service in the WNBA, position, and performance statistics.

Results:

On average, players were 28 years of age at the time of Achilles tendon rupture, with a service time in the WNBA of 6.5 years. Four players never returned to play in the WNBA, while 7 players failed to play more than 1 season. Players who did return played significantly fewer minutes per game compared with preinjury in both postinjury seasons 1 and 2 (mean difference, –6.11 and –6.54 min/game, respectively; P < .01 for both) and had a significantly decreased PER in postinjury season 2 (mean difference, –2.53; P = .024). After returning to play, the injured players experienced significant decreases when compared with controls in field goals (–0.85 vs +0.20; P = .047), free throws (–1.04 vs +0.12; P < .01), steals (–0.48 vs +0.24; P = .018), and points scored (–2.89 vs +0.58; P = .014).

Conclusion:

WNBA players experienced significant decreases in performance metrics after Achilles tendon rupture compared with their preinjury levels and compared with uninjured controls. Overall, 23.5% of players failed to return to the WNBA, while 41.2% failed to play for more than 1 season.

Influence of Achilles tendon rupture site on surgical repair outcomes

PURPOSE

This study aims to measure the distance between the common site of Achilles tendon rupture and calcaneal insertion through ultrasound and to compare the outcomes between proximal and distal rupture groups.

METHODS

We investigated the electronic medical records of 117 patients and preoperative ultrasound describing the rupture site. Among 88 patients, we compared the patient-reported outcome and re-rupture rate of proximal and distal rupture groups.

RESULTS

The mean rupture site of the 117 included subjects was 4.5 ± 1.3 cm. The rupture site had a weak negative correlation with body mass index (ρ = -0.230, P = 0.013). Furthermore, 77% of the patients with distal rupture reported good outcome (Achilles Tendon Rupture Score > 80) compared to 56% of the patients with proximal rupture (P = 0.041).

CONCLUSION

Patients with proximal rupture had less satisfactory postoperative outcomes than those with distal rupture.

Arthroscopic Tenotomy of the Long Head of the Biceps Tendon and Section of the Anterior Joint Capsule Produce Moderate Osteoarthritic Changes in an Experimental Sheep Model

Osteoarthritis (OA) of the glenohumeral (GH) joint is a common cause of shoulder pain, resulting in considerable invalidity. Unfortunately, the study of its pathogenesis is challenging. Models of OA are necessary to identify specific targets for therapy and to be able to interfere with the development and evolution of OA. This study aims to assess the effect of an arthroscopic tenotomy of the long head of the biceps tendon (LHBT) and section of the anterior glenohumeral joint capsule on the ovine glenohumeral joint. In addition, the authors aim to validate and evaluate the reliability of a modified semi-quantitative MRI score to assess joint degeneration in a sheep’s shoulder. Eight skeletally mature sheep received an arthroscopic tenotomy of the LHBT and section of the anterior joint capsule and were euthanized four months after surgery. All animals tolerated the surgery well, and no complication was recorded for six weeks. Moderate degenerative changes to the ovine shoulder joint were found on MRI and histological evaluation. The arthroscopic tenotomy of the LHBT and the anterior glenohumeral joint capsule section caused moderate degenerative changes to the ovine shoulder joint.

Small interfering RNAs in tendon homeostasis

BACKGROUND

Tenogenesis and tendon homeostasis are guided by genes encoding for the structural molecules of tendon fibres. Small interfering RNAs (siRNAs), acting on gene regulation, can therefore participate in the process of tendon healing.

SOURCES OF DATA

A systematic search of different databases to October 2020 identified 17 suitable studies.

AREAS OF AGREEMENT

SiRNAs can be useful to study reparative processes of tendons and identify possible therapeutic targets in tendon healing.

AREAS OF CONTROVERSY

Many genes and growth factors involved in the processes of tendinopathy and tendon healing can be regulated by siRNAs. It is however unclear which gene silencing determines the expected effect.

GROWING POINTS

Gene dysregulation of growth factors and tendon structural proteins can be influenced by siRNA.

AREAS TIMELY FOR DEVELOPING RESEARCH

It is not clear whether there is a direct action of the siRNAs that can be used to facilitate the repair processes of tendons.

Biologics in the Treatment of Achilles Tendon

The treatment of Achilles tendinitis from conservative to minimally invasive to surgery gives patients a wide range of treatment options for this common pathology. The use and role of biologics to augment this treatment is emerging. The use of biologics may enhance the healing potential of the Achilles tendon when conservative treatment fails. There are a handful of biologics being investigated to obtain if improved outcomes can be maximized.

Achilles Tendon Rupture: Mechanisms of Injury, Principles of Rehabilitation and Return to Play

The Achilles tendon is the thickest, strongest and largest tendon in the human body, but despite its size and tensile strength, it frequently gets injured. Achilles tendon ruptures (ATRs) mainly occur during sports activities, and their incidence has increased over the last few decades. Achilles tendon tears necessitate a prolonged recovery time, sometimes leaving long-term functional limitations. Treatment options include conservative treatment and surgical repair. There is no consensus on which is the best treatment for ATRs, and their management is still controversial. Limited scientific evidence is available for optimized rehabilitation regimen and on the course of recovery after ATRs. Furthermore, there are no universally accepted outcomes regarding the return to play (RTP) process. Therefore, the aim of this narrative review is to give an insight into the mechanism of injuries of an ATR, related principles of rehabilitation, and RTP.

Characteristics of L-PRP preparations for treating Achilles tendon rupture within the PATH-2 study

Platelet-rich plasma (PRP) is an autologous preparation that has been claimed to improve healing and mechanobiological properties of tendons both in vitro and in vivo. In this sub-study from the PATH-2 (PRP in Achilles Tendon Healing-2) trial, we report the cellular and growth factor content and quality of the Leukocyte-rich PRP (L-PRP) (N = 103) prepared using a standardized commercial preparation method across 19 different UK centers. Baseline whole blood cell counts (red cells, leukocyte and platelets) demonstrated that the two groups were well-matched. L-PRP analysis gave a mean platelet count of 852.6 x 10⁹/L (SD 438.96), a mean leukocyte cell count of 15.13 x 10⁹/L (SD 10.28) and a mean red blood cell count of 0.91 x 10¹²/L (SD 1.49). The activation status of the L-PRP gave either low or high expression levels of the degranulation marker CD62p before and after ex-vivo platelet activation respectively. TGF-β, VEGF, PDGF, IGF and FGFb mean concentrations were 131.92 ng/ml, 0.98 ng/ml, 55.34 ng/ml, 78.2 ng/ml and 111.0 pg/ml respectively with expected correlations with both platelet and leukocyte counts. While PATH-2 results demonstrated that there was no evidence L-PRP is effective for improving clinical outcomes at 24 weeks after Achilles tendon rupture, our findings support that the majority of L-PRP properties were within the method specification and performance.

Minimally Invasive Achilles Repair Techniques

Achilles tendon rupture is an increasingly common problem with an aging population participating in high-level physical activities. Appropriate treatment has been debated for decades, but good outcomes have been reported after conservative and surgical management. The development of minimally invasive surgical techniques for Achilles repair has reduced the incidence of complications and maintained the high level of function reported after open surgery. The Achilles Midsubstance SpeedBridge repair is a newer minimally invasive technique that has demonstrated promising results and is the authors' preferred treatment of Achilles tendon rupture in athletes and active patients.

In Vivo and In Vitro Mechanical Loading of Mouse Achilles Tendons and Tenocytes-A Pilot Study

Mechanical force is a key factor for the maintenance, adaptation, and function of tendons. Investigating the impact of mechanical loading in tenocytes and tendons might provide important information on in vivo tendon mechanobiology. Therefore, the study aimed at understanding if an in vitro loading set up of tenocytes leads to similar regulations of cell shape and gene expression, as loading of the Achilles tendon in an in vivo mouse model. In vivo: The left tibiae of mice (n = 12) were subject to axial cyclic compressive loading for 3 weeks, and the Achilles tendons were harvested. The right tibiae served as the internal non-loaded control. In vitro: tenocytes were isolated from mice Achilles tendons and were loaded for 4 h or 5 days (n = 6 per group) based on the in vivo protocol. Histology showed significant differences in the cell shape between in vivo and in vitro loading. On the molecular level, quantitative real-time PCR revealed significant differences in the gene expression of collagen type I and III and of the matrix metalloproteinases (MMP). Tendon-associated markers showed a similar expression profile. This study showed that the gene expression of tendon markers was similar, whereas significant changes in the expression of extracellular matrix (ECM) related genes were detected between in vivo and in vitro loading. This first pilot study is important for understanding to which extent in vitro stimulation set-ups of tenocytes can mimic in vivo characteristics.

Needle biopsy-derived myofascial tissue samples are sufficient for quantification of myofibroblast density

Quantification of myofibroblasts is a promising method for assessing tissue properties in the field of fascia research. This is commonly performed by immunohistochemistry for α-smooth muscle actin. However, usually larger tissue samples sizes are required for quantification. The aim of this investigation was to explore whether a microscopic quantification of myofibroblasts can be conducted with fascial tissue samples derived via percutaneous needle biopsy. Fascial tissues were derived via percutaneous needle biopsy from the fascia lata of 11 persons (aged 19-40 years). Following immunohistochemistry, selected fields for photomicroscopic analysis were chosen by a Monte Carlo method based randomization procedure. On these fields, a digital quantification for the relative density of α-smooth muscle actin was attempted. The newly developed quantification method could successfully be applied in all tissue samples. The median α-smooth muscle actin density in the selected tissue samples ranged between 0% and 1.7% (median 0%, IQR 0%-0.001%). The applied protocol proved to be workable for the purpose of an estimation of the α-smooth muscle actin density in fascial tissue samples derived via percutaneous needle biopsy. Since this type of biopsy is less invasive than the commonly performed open muscle biopsy, this offers a new and useful perspective for future histological investigations of fascial tissue properties in living patients. Clin. Anat. 31:368-372, 2018. © 2018 Wiley Periodicals, Inc.

Different Achilles Tendon Pathologies Show Distinct Histological and Molecular Characteristics

Reasons for the development of chronic tendon pathologies are still under debate and more basic knowledge is needed about the different diseases. The aim of the present study was therefore to characterize different acute and chronic Achilles tendon disorders. Achilles tendon samples from patients with chronic tendinopathy (n = 7), chronic ruptures (n = 6), acute ruptures (n = 13), and intact tendons (n = 4) were analyzed. The histological score investigating pathological changes was significantly increased in tendinopathy and chronic ruptures compared to acute ruptures. Inflammatory infiltration was detected by immunohistochemistry in all tendon pathology groups, but was significantly lower in tendinopathy compared to chronic ruptures. Quantitative real-time PCR (qRT-PCR) analysis revealed significantly altered expression of genes related to collagens and matrix modeling/remodeling (matrix metalloproteinases, tissue inhibitors of metalloproteinases) in tendinopathy and chronic ruptures compared to intact tendons and/or acute ruptures. In all three tendon pathology groups markers of inflammation (interleukin (IL) 1β, tumor necrosis factor α, IL6, IL10, IL33, soluble ST2, transforming growth factor β1, cyclooxygenase 2), inflammatory cells (cluster of differentaition (CD) 3, CD68, CD80, CD206), fat metabolism (fatty acid binding protein 4, peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein α, adiponectin), and innervation (protein gene product 9.5, growth associated protein 43, macrophage migration inhibitory factor) were detectable, but only in acute ruptures significantly regulated compared to intact tendons. The study gives an insight into structural and molecular changes of pathological processes in tendons and might be used to identify targets for future therapy of tendon pathologies.

Tendon end separation with loading in an Achilles tendon repair model: comparison of non-absorbable vs. absorbable sutures

Background

Rupture of the Achilles tendon often leads to long-term morbidity, particularly calf weakness associated with tendon elongation. Operative repair of Achilles tendon ruptures leads to reduced tendon elongation. Tendon lengthening is a key problem in the restoration of function following Achilles tendon rupture. A study was performed to determine differences in initial separation, strength and failure characteristics of differing sutures and numbers of core strands in a percutaneous Achilles tendon repair model in response to initial loading.

Methods

Nineteen bovine Achilles tendons were repaired using a percutaneous/minimally invasive technique with a combination of a modified Bunnell suture proximally and a Kessler suture distally, using non-absorbable 4-strand 6-strand repairs and absorbable 8-strand sutures. Specimens were then cyclically loaded using phases of 10 cycles of 100 N, 100 cycles of 100 N, 100 cycles of 190 N consistent with early range of motion training and weight-bearing, before being loaded to failure.

Results

Pre-conditioning of 10 cycles of 100 N resulted in separations of 4 mm for 6-strand, 5.9 mm for 4-strand, but 11.5 mm in 8-strand repairs, this comprised 48.5, 68.6 and 72.7% of the separation that occurred after 100 cycles of 100 N. The tendon separation after the third phase of 100 cycles of 190 N was 17.4 mm for 4-strand repairs, 16.6 mm for 6-strand repairs and 26.6 mm for 8-strand repairs. There were significant differences between the groups (p < 0.0001). Four and six strand non-absorbable repairs had significantly less separation than 8-strand absorbable repairs (p = 0.017 and p = 0.04 respectively).

The mean (SEM) ultimate tensile strengths were 4-strand 464.8 N (27.4), 6-strand 543.5 N (49.6) and 8-strand 422.1 N (80.5). Regression analysis reveals no significant difference between the overall strength of the 3 repair models (p = 0.32) (4 vs. 6: p = 0.30, 4 vs. 8: p = 0.87; 6 vs. 8: p = 0.39). The most common mode of failure was pull out of the Kessler suture from the distal stump in 41.7% of specimens.

Conclusion

The use of a non-absorbable suture resulted in less end-to-end separation when compared to absorbable sutures when an Achilles tendon repair model was subject to cyclical loading. Ultimate failure occurred more commonly at the distal Kessler suture end although this occurred with separations in excess of clinical failure. The effect of early movement and loading on the Achilles tendon is not fully understood and requires more research.

Acute Achilles Tendon Rupture: Clinical Evaluation, Conservative Management, and Early Active Rehabilitation

The Achilles tendon (AT) is the strongest, largest, and most commonly ruptured tendon in the human body. Physical examination provides high sensitivity and specificity. Imaging studies are not recommended unless there are equivocal findings in the physical examination. Recent studies have shown that the risk of re-rupture is negated with implementation of functional rehabilitation protocols. Heterogeneity in study design makes conclusions on the specifics of functional rehabilitation protocols difficult; however, it is clear that early weight bearing and early controlled mobilization lead to better patient outcome and satisfaction in both surgically and conservatively treated populations.

The Internal Brace for Midsubstance Achilles Ruptures

The efficient and effective function of the Achilles tendon is essential for normal gait and sporting performance. The optimal technique for the operative repair of the Achilles midsubstance rupture remains controversial. Suboptimal outcomes are common even after successful Achilles repair. Factors contributing to poor outcomes include a tenuous soft tissue envelope (leading to wound complications, peritendinous adhesions, and poor tendon healing,) as well as failure to maintain appropriate musculotendinous length, even after successful repair.We present a new technique using the InternalBrace (IB) and a modification of the Percutaneous Achilles Repair System (PARS; Arthrex Inc, Naples, FL), the Achilles Mid-Substance Speed Bridge Repair. This IB approach is knotless, respects the soft tissue envelope, and allows the appropriate musculotendinous length to be set intraoperatively. The IB principle enables direct fixation to bone allowing early mobilization while minimizing the risk of knot slippage, accelerating recovery, and allowing for restoration of normal function.

LEVEL OF EVIDENCE

Level V, expert opinion.

The Role of Detraining in Tendon Mechanobiology

Introduction: Several conditions such as training, aging, estrogen deficiency and drugs could affect the biological and anatomo-physiological characteristics of the tendon. Additionally, recent preclinical and clinical studies examined the effect of detraining on tendon, showing alterations in its structure and morphology and in tenocyte mechanobiology. However, few data evaluated the importance that cessation of training might have on tendon. Basically, we do not fully understand how tendons react to a phase of training followed by sudden detraining. Therefore, within this review, we summarize the studies where tendon detraining was examined.

Materials and Methods: A descriptive systematic literature review was carried out by searching three databases (PubMed, Scopus and Web of Knowledge) on tendon detraining. Original articles in English from 2000 to 2015 were included. In addition, the search was extended to the reference lists of the selected articles. A public reference manager (www.mendeley.com) was adopted to remove duplicate articles.

Results: An initial literature search yielded 134 references (www.pubmed.org: 53; www.scopus.com: 11; www.webofknowledge.com: 70). Fifteen publications were extracted based on the title for further analysis by two independent reviewers. Abstracts and complete articles were after that reviewed to evaluate if they met inclusion criteria.

Conclusions: The revised literature comprised four clinical studies and an in vitro and three in vivo reports. Overall, the results showed that tendon structure and properties after detraining are compromised, with an alteration in the tissue structural organization and mechanical properties. Clinical studies usually showed a lesser extent of tendon alterations, probably because preclinical studies permit an in-depth evaluation of tendon modifications, which is hard to perform in human subjects. In conclusion, after a period of sudden detraining (e.g., after an injury), physical activity should be taken with caution, following a targeted rehabilitation program. However, further research should be performed to fully understand the effect of sudden detraining on tendons.

The Neglected Achilles Tendon Rupture Repaired With Allograft: A Review of 14 Cases

Various surgical techniques have been reported for the repair of neglected Achilles tendon ruptures, including V-Y advancements, synthetic augmentations, and collagen implants. The use of an Achilles tendon allograft allows bridging of large defects without donor site morbidity, with a relative ease of technique and adequate graft availability. The present retrospective report focused on the outcomes of a series of 14 patients with neglected ruptures treated with an Achilles tendon allograft. Patients were included in the present series if they had ≥12 months of postoperative follow-up data available and the allograft had been used without any adjunctive procedures. Of the 14 patients, 6 were female (43%) and 8 were male (57%), with a mean follow-up period of 16.1 ± 3 (range 12 to 27) months. The mean interval from the initial injury to surgery was 6.9 ± 5 (range 1 to 28) months. The mean intraoperative defect size was 7.0 ± 3 (range 4 to 15) cm. A calcaneal block was used in 2 patients (14%). All patients were able to perform a single heel rise at a mean of 27 ± 11 (range 12 to 37) weeks postoperatively. Weightbearing in normal shoe gear was achieved at a mean of 13.5 ± 3 (range 12 to 17) weeks. Complications included 1 delayed union (7%) of the calcaneal bone block. Repair of the neglected Achilles tendon rupture with an allograft appears to be an acceptable approach, with good overall outcomes and low risk. These results suggest that this method of repair compares favorably with established alternatives.

Not All Tendons Are Created Equal: Implications for Differing Treatment Approaches

The majority of muscles have distinct tendinous attachments to bones; however, only a few tendons develop painful conditions. That simple observation prompts us to ask a few questions. Are there commonalities in morphology and pathology among the painful tendons? What contributes to the propensity for pathology in some, but not all, tendons? And, consequently, should all tendinopathies be managed equally? Two common tendinopathies are those affecting the Achilles and supraspinatus, which are presented in this special issue and serve as excellent models to discuss similarities and contrasts. J Orthop Sports Phys Ther 2015;45(11):829-832. doi:10.2519/jospt.2015.0114.

Healing of human Achilles tendon ruptures: radiodensity reflects mechanical properties

PURPOSE

This study tests the idea of using radiodensity from computed tomography to quantitatively evaluate the healing of ruptured Achilles tendons.

METHODS

The radiodensity of the healing tendons in sixty-five patients who were treated for Achilles tendon rupture was measured. The hypothesis was that density would correlate with an estimate for e-modulus, derived from strain, measured by radiostereometry with different mechanical loadings.

RESULTS

Radiodensity 7 weeks after injury was decreased to 67 % (SD 11) of the contralateral, uninjured tendon. There was no improvement in radiodensity from 7 to 19 weeks, whereas at 1 year, it had increased to 106 % (SD 7). Only 2 of 52 measured values at 1 year were lower than the highest value at 19 weeks, i.e. there was minimal overlap. The variation in radiodensity could explain 80 % of the variation in e-modulus, but radiodensity correlated only weakly with e-modulus at each time point separately. At 1 year, both radiodensity and e-modulus correlated with functional results, although weakly.

CONCLUSIONS

From 19 weeks onwards, radiodensity appears to reflect mechanical properties of the tendon and might to some extent predict the final outcome. Radiodensity at 7 weeks is difficult to interpret, probably because it reflects both callus and damaged tissues.

Pharmacological interventions for the treatment of Achilles tendinopathy: a systematic review of randomized controlled trials

INTRODUCTION

Several pharmacological interventions have been proposed for the management of Achilles tendinopathy, with no agreement on which is the overall best option available. This systematic review investigates the efficacy and safety of different local pharmacological treatments for Achilles tendinopathy.

SOURCES OF DATA

We included only randomized controlled studies (RCTs) focusing on clinical and functional outcomes of therapies consisting in injection of a substance or local application. Assessment of the methodological quality was performed using a modified version of the Coleman methodology score (CMS) to determine possible risks of bias.

AREAS OF AGREEMENT

Thirteen RCTs were included with a total of 528 studied patients. Eleven studies reported the outcomes of injection therapies. Two studies examined the outcomes of patients who applied glyceryl trinitrate patch. The mean modified CMS was 70.6 out of 90.

AREAS OF CONTROVERSY

There was no significant evidence of remarkable benefits provided by any of the therapies studied.

GROWING POINTS

There is not univocal evidence to advise any particular pharmacological treatment as the best advisable non-operative option for Achilles tendinopathy as equivalent alternative to the most commonly used eccentric loading rehabilitation program. However, potential was shown by the combination of different substances administered with physical therapy.

RESEARCH

There is a need for more long-term investigations, studying large enough cohort with standardized scores and evaluations shared by all the investigations to confirm the healing potential, and provide a stronger statistical comparison of the available treatments.

Randomized controlled trial of accelerated rehabilitation versus standard protocol following surgical repair of ruptured Achilles tendon

BACKGROUND

There is no consensus regarding the optimal management of the acutely ruptured Achilles tendon (TA). Functional bracing alone achieves outcomes similar to those of surgical repair. Surgical repair combined with immediate mobilization may improve the clinical outcome further. The purpose of our study was to determine if an accelerated rehabilitation programme following surgical repair of the ruptured TA could improve clinical outcome, relative to the standard protocol.

METHODS

Patients with an acutely ruptured TA were randomly allocated to undergo an accelerated programme (AP) or standard programme (SP), following surgery. Outcome was assessed at 12 months post-surgery using the Achilles tendon Total Rupture Score (ATRS), the heel-raise height and the time taken to return to running.

RESULTS

Fifty-one patients completed the study, 25 in the AP group and 26 in the SP group. At 12 months post-surgery, the ATRS results were similar in the two treatment groups (87.46 in AP with standard error (SE) of 0.735 versus 87.12 in SP with SE of 0.75) while the AP group had less lengthening of the TA (0.385 cm, SE 0.166 versus 1.00 cm, SE 0.169) and a more rapid return to running (17.231 weeks, SE 0.401 versus 21.08 weeks, SE 0.409), than the SP group.

CONCLUSION

The accelerated rehabilitation programme resulted in less tendon lengthening, more rapid return to running, but similar ATRS relative to the standard rehabilitation. Immobilization following TA repair may prolong recovery.

Characterization of age-related changes of tendon stem cells from adult human tendons

PURPOSE

The present study evaluated the presence of stem cells in hamstring tendons from adult subjects of different ages. The aim was to isolate, characterize and expand these cells in vitro, and to evaluate whether cell activities are influenced by age.

METHODS

Tendon stem cells (TSCs) were isolated through magnetic sorting from the hamstring tendons of six patients. TSC percentage, morphology and clonogenic potential were evaluated, as well as the expression of specific surface markers. TSC multi-potency was also investigated as a function of age, and quantitative polimerase chain reaction was used to evaluate gene expression of TSCs cultured in suitable differentiating media.

RESULTS

The presence of easily harvestable stem cell population within adult human hamstring tendons was demonstrated. These cells exhibit features such as clonogenicity, multi-potency and mesenchymal stem cells markers expression. The age-related variations in human TSCs affect the number of isolated cells and their self-renewal potential, while multi-potency assays are not influenced by tendon ageing, even though cells from younger individuals expressed higher levels of osteogenic and adipogenic genes, while chondrogenic genes were highly expressed in cells from older individuals.

CONCLUSIONS

These results may open new opportunities to study TSCs to better understand tendon physiology, healing and pathological processes such as tendinopathy and degenerative age-related changes opening new frontiers in the management of tendinopathy and tendon ruptures.

Differences in elements between intact and disrupted human ligamenta capitum femorum

To compare the element compositions between intact (i.e., intact throughout its length) and disrupted (i.e., ligament no longer attached to the attachment) ligaments, the contents of elements in the human ligamenta capitum femorum (LCF) were analyzed by inductively coupled plasma-atomic emission spectrometry. Histological and immunohistological assessments were also performed in both groups. The subjects were 8 men and 32 women. Trace element analyses showed that the sulfur and iron contents were significantly greater in the intact group than in the disrupted group, while the phosphorus and magnesium contents were significantly smaller in the intact group than in the disrupted group. The calcium and zinc contents were smaller in the intact group than in the disrupted group, with no significant differences. Histologically, there were fibrocartilage cells and extracellular matrix metachromasia in ligaments of the intact group. In contrast, fibrocartilage cells disappeared, and fat cells appeared instead of collagen fibrils in ligaments of the disrupted group. The LCFs of the intact group were immunohistologically positive for all components examined including collagens, glycosaminoglycans, and proteoglycans. The increase in sulfur suggested the presence of high glycosaminoglycan levels associated with fibrocartilaginous metaplasia in the ligament by compressive force. The reduction in iron may show a decreased number of blood vessels in the synovium after ligament disruption. The increases in phosphorus, magnesium, and calcium are indicative of degenerative changes including calcification and ossification. We conclude that differences in the contents of elements between intact and disrupted LCFs indicate degenerative alterations to the ligament structure after disruption.

Histological scoring systems for tissue-engineered, ex vivo and degenerative meniscus

PURPOSE

Because its function is strictly related to the quality of meniscal tissue, one of the most important outcome measures for the evaluation of meniscal repair effectiveness is the assessment of histological features. Data on the validation and application of the histological scoring systems in research settings and specific fields of meniscal disorders are lacking. The available histological scoring systems to assess meniscal tissue were systematically evaluated.

METHODS

Histological scoring systems for the analysis of degenerative meniscal changes, ex vivo and tissue-engineered meniscal repair were reviewed. Furthermore, the validity and applicability of the scoring systems were assessed.

RESULTS

The Copenhaver classification and Mankin score have been modified to classify the degeneration of collagen bundles in the meniscal structure. The Pauli score seems to be a comprehensive and simple scoring system for the evaluation of both macroscopic and histologic meniscal changes related to ageing and osteoarthritic degeneration. The Zhang score may be used for ex vivo gene therapy in meniscus healing. The Ishida score seems to be the most adequate for the evaluation of tissue-engineered meniscal repair.

CONCLUSION

Although several histological scoring systems are available to assess meniscal structure, only few of them have been validated for specific application in research settings. Validated scores are required to provide a standardized data collection to allow the comparison of results of different research groups. Further experimental and clinical studies are needed to find a comprehensive and validated histological scoring system in the field of meniscus repair.

LEVEL OF EVIDENCE

Systematic review of Level III studies, Level III.

Achilles tendon rupture in women

BACKGROUND

The incidence of Achilles rupture appears to be less in women, although this notion has not been specifically investigated in the literature.

METHODS

The medical records of 7 foot-and-ankle orthopaedic surgeons at 1 institution were reviewed by Current Procedural Terminology (code 27650) and International Classification of Diseases-9 (code 727.67) to establish all Achilles tendon ruptures seen and/or treated by these surgeons. Sex, age, side, and mechanism of injury were recorded. Whether the patient had an acute Achilles tendon rupture or nonacute Achilles pathology was also noted.

RESULTS

A total of 468 patients were identified, of whom 358 had acute ruptures: 302 male and 56 female (5.39:1). Patients with acute ruptures were significantly younger than those with nonacute pathology (43.8 vs 55.1, P < .001). For acute ruptures, the mean age was not significantly different between men and women (43.9 vs 43.2; P = .780). Athletic activity was causative in 243 of 302 men (80.5%) and in 40 of 56 women (71.4%). This difference was not statistically significant (P = .130). Six men (2.0%) and 6 women (10.7%) had comorbidities that were thought to increase their risk of rupture (P = .005).

CONCLUSION

Achilles tendon rupture is more common in men than women. Previous studies using the aforementioned codes to identify patients without chart review may have overestimated the number of women with acute Achilles tendon rupture.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Stem cell therapy for tendon injury

Tendon injury may occur suddenly or progressively, and can be divided into tendon rupture or tendinopathy based on the severity of injury. It is frequently found in professional or nonprofessional people who are making repetitive movements. In aged people, tendon degeneration becomes obvious; their tendon injuries are then frequently evident. No effective therapies for tendon injury are currently available. In this article, we review the tendon structure, mechanisms of tendon injury, and tendon healing process. More importantly, cell-based therapies for tendon injury are fully addressed, which will play an important role for tendon therapy in the near future.

A biomechanical comparison of the primary stability of two minimally invasive techniques for repair of ruptured Achilles tendon

PURPOSE

To compare the primary stability of two minimally invasive procedures of Achilles tendon (AT) repair, namely a modified percutaneous repair of ruptured AT and the Achillon suture configuration.

METHODS

Eighteen (nine matched pairs) frozen ovine ATs were tenotomized 5 cm from the calcaneal insertion. In each pair, one tendon was randomly allocated to one of the two techniques: a modified percutaneous repair group and the Achillon device suture configuration. Specimens were tested performing an unidirectional tensile load to failure using a servo-hydraulic testing device (MTS Systems, Eden Prairie, MN, USA), controlled by an electropulse e3000 INSTRON machine (Instron Ltd, Buckinghamshire, UK). The tendons were then loaded to failure at a rate of 10 mm/s.

RESULTS

Two of the nine pairs of specimens were discarded because one specimen for each of the pair pulled out of the pneumatic clamp during mechanical testing. The remaining seven matched pairs were successfully tested. There were no differences in mean strength, mean maximum load, mean failure elongation, tension, stiffness and mode of failure between the two groups.

CONCLUSION

The Achillon-like configuration and the modified percutaneous repair of ruptured AT provided similar biomechanical performance.

Deficits in heel-rise height and achilles tendon elongation occur in patients recovering from an Achilles tendon rupture

BACKGROUND

Whether an Achilles tendon rupture is treated surgically or not, complications such as muscle weakness, decrease in heel-rise height, and gait abnormalities persist after injury.

PURPOSE

The purpose of this study was to evaluate if side-to-side differences in maximal heel-rise height can be explained by differences in Achilles tendon length.

STUDY DESIGN

Case series; level of evidence, 4.

METHOD

Eight patients (mean [SD] age of 46 [13] years) with acute Achilles tendon rupture and 10 healthy subjects (mean [SD] age of 28 [8] years) were included in the study. Heel-rise height, Achilles tendon length, and patient-reported outcome were measured 3, 6, and 12 months after injury. Achilles tendon length was evaluated using motion analysis and ultrasound imaging.

RESULTS

The Achilles tendon length test-retest reliability (intraclass correlation coefficient = 0.97) was excellent. For the healthy subjects, there were no side-to-side differences in tendon length and heel-rise height. Patients with Achilles tendon ruptures had significant differences between the injured and uninjured side for both tendon length (mean [SD] difference, 2.6-3.1 [1.2-1.4] cm, P = .017-.028) and heel-rise height (mean [SD] difference, -4.1 to -6.1 [1.7-1.8] cm, P = .012-.028). There were significant negative correlations (r = -0.943, P = .002, and r = -0.738, P = .037) between the side-to-side difference in heel-rise height and Achilles tendon length at the 6- and 12-month evaluations, respectively.

CONCLUSION

The side-to-side difference found in maximal heel-rise height can be explained by a difference in Achilles tendon length in patients recovering from an Achilles tendon rupture. Minimizing tendon elongation appears to be an important treatment goal when aiming for full return of function.

Peroneus brevis tendon transfer for reconstruction of chronic tears of the Achilles tendon: a long-term follow-up study

BACKGROUND

Chronic tears of the Achilles tendon can result in substantial loss of function. Those tears with a tendon gap of up to 6.5 cm can be treated surgically with use of an autologous peroneus brevis tendon graft.

METHODS

At an average follow-up period of 15.5 years after the surgery, we examined sixteen of twenty-two patients who had undergone peroneus brevis tendon graft reconstruction for a chronic Achilles tendon tear. Clinical and functional assessment was performed.

RESULTS

All sixteen patients were able to walk on tiptoe, and no patient used a heel lift or walked with a visible limp. The maximum calf circumference of the involved limb remained significantly decreased. The involved limb was significantly less strong than the contralateral one. One patient had developed a tendinopathy of the opposite Achilles tendon, one had developed a tendinopathy of the reconstructed tendon, and one had ruptured the contralateral Achilles tendon five years after the original injury.

CONCLUSIONS

The long-term results of treatment of chronic tears of the Achilles tendon by means of autologous peroneus brevis tendon grafting are encouraging. Patients retain good functional results despite permanently impaired ankle plantar flexion strength and decreased calf circumference.

Local biochemical and morphological differences in human Achilles tendinopathy: a case control study

Background

The incidence of Achilles tendinopathy is high and underlying etiology as well as biochemical and morphological pathology associated with the disease is largely unknown. The aim of the present study was to describe biochemical and morphological differences in chronic Achilles tendinopathy. The expressions of growth factors, inflammatory mediators and tendon morphology were determined in both chronically diseased and healthy tendon parts.

Methods

Thirty Achilles tendinopathy patients were randomized to an expression-study (n = 16) or a structural-study (n = 14). Biopsies from two areas in the Achilles tendon were taken and structural parameters: fibril density, fibril size, volume fraction of cells and the nucleus/cytoplasm ratio of cells were determined. Further gene expressions of various genes were analyzed.

Results

Significantly smaller collagen fibrils and a higher volume fraction of cells were observed in the tendinopathic region of the tendon. Markers for collagen and its synthesis collagen 1, collagen 3, fibronectin, tenascin-c, transforming growth factor-β fibromodulin, and markers of collagen breakdown matrix metalloproteinase-2, matrix metalloproteinase-9 and metallopeptidase inhibitor-2 were significantly increased in the tendinopathic region. No altered expressions of markers for fibrillogenesis, inflammation or wound healing were observed.

Conclusion

The present study indicates that an increased expression of factors stimulating the turnover of connective tissue is present in the diseased part of tendinopathic tendons, associated with an increased number of cells in the injured area as well as an increased number of smaller and thinner fibrils in the diseased tendon region. As no fibrillogenesis, inflammation or wound healing could be detected, the present data supports the notion that tendinopathy is an ongoing degenerative process.

Trial registration

Current Controlled Trials ISRCTN20896880

Biological factors in the pathogenesis of rotator cuff tears

Rotator cuff tears are common, and lead to shoulder pain and functional impairment. Despite their frequency and related disability, etiology and pathogenesis are still debated. Multiple factors contribute to tears of the rotator cuff. Extrinsic factors are anatomic variables, such as acromial morphologic characteristics, os acromiale, and acromial spurs that compress the rotator cuff by bony impingement or direct pressure from the surrounding soft tissue. Intrinsic factors arise from the tendon itself, because of tensile overload, aging, microvascular supply, traumatisms, or degeneration. Little information is available from a cellular and molecular point of view. We reviewed the biological factors involved in the pathogenesis of rotator cuff tears. Understanding the mechanism of rotator cuff pathology would facilitate the rationale for therapeutic interventions, by guiding the design, selection, and implementation of treatment strategies such as biologic modulation and preventive measures.

Biological strategies to enhance healing of the avascular area of the meniscus

Meniscal injuries in the vascularized peripheral part of the meniscus have a better healing potential than tears in the central avascular zone because meniscal healing principally depends on its vascular supply. Several biological strategies have been proposed to enhance healing of the avascular area of the meniscus: abrasion therapy, fibrin clot, organ culture, cell therapy, and applications of growth factors. However, data are too heterogeneous to achieve definitive conclusions on the use of these techniques for routine management of meniscal lesions. Although most preclinical and clinical studies are very promising, they are still at an experimental stage. More prospective randomised controlled trials are needed to compare the different techniques for clinical results, applicability, and cost-effectiveness.

Scaffolds in tendon tissue engineering

Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing tendon disorders. Tissue engineering strategies to improve tendon repair healing include the use of scaffolds, growth factors, cell seeding, or a combination of these approaches. Scaffolds have been the most common strategy investigated to date. Available scaffolds for tendon repair include both biological scaffolds, obtained from mammalian tissues, and synthetic scaffolds, manufactured from chemical compounds. Preliminary studies support the idea that scaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potential. However, available data are lacking to allow definitive conclusion on the use of scaffolds for tendon augmentation. We review the current basic science and clinical understanding in the field of scaffolds and tissue engineering for tendon repair.

Tissue engineered strategies for skeletal muscle injury

Skeletal muscle injuries are common in athletes, occurring with direct and indirect mechanisms and marked residual effects, such as severe long-term pain and physical disability. Current therapy consists of conservative management including RICE protocol (rest, ice, compression and elevation), nonsteroidal anti-inflammatory drugs, and intramuscular corticosteroids. However, current management of muscle injuries often does not provide optimal restoration to preinjury status. New biological therapies, such as injection of platelet-rich plasma and stem-cell-based therapy, are appealing. Although some studies support PRP application in muscle-injury management, reasons for concern persist, and further research is required for a standardized and safe use of PRP in clinical practice. The role of stem cells needs to be confirmed, as studies are still limited and inconsistent. Further research is needed to identify mechanisms involved in muscle regeneration and in survival, proliferation, and differentiation of stem cells.

Tissue engineering for rotator cuff repair: an evidence-based systematic review

The purpose of this systematic review was to address the treatment of rotator cuff tears by applying tissue engineering approaches to improve tendon healing, specifically platelet rich plasma (PRP) augmentation, stem cells, and scaffolds. Our systematic search was performed using the combination of the following terms: “rotator cuff”, “shoulder”, “PRP”, “platelet rich plasma”, “stemcells”, “scaffold”, “growth factors”, and “tissue engineering”. No level I or II studies were found on the use of scaffolds and stem cells for rotator cuff repair. Three studies compared rotator cuff repair with or without PRP augmentation. All authors performed arthroscopic rotator cuff repair with different techniques of suture anchor fixation and different PRP augmentation. The three studies found no difference in clinical rating scales and functional outcomes between PRP and control groups. Only one study showed clinical statistically significant difference between the two groups at the 3-month follow up. Any statistically significant difference in the rates of tendon rerupture between the control group and the PRP group was found using the magnetic resonance imaging. The current literature on tissue engineering application for rotator cuff repair is scanty. Comparative studies included in this review suggest that PRP augmented repair of a rotator cuff does not yield improved functional and clinical outcome compared with non-augmented repair at a medium and long-term followup.

Growth factors and anticatabolic substances for prevention and management of intervertebral disc degeneration

Intervertebral disc (IVD) degeneration is frequent, appearing from the second decade of life and progressing with age. Conservative management often fails, and patients with IVD degeneration may need surgical intervention. Several treatment strategies have been proposed, although only surgical discectomy and arthrodesis have been proved to be predictably effective. Biological strategies aim to prevent and manage IVD degeneration, improving the function and anabolic and reparative capabilities of the nucleus pulposus and annulus fibrosus cells and inhibiting matrix degradation. At present, clinical applications are still in their infancy. Further studies are required to clarify the role of growth factors and anticatabolic substances for prevention and management of intervertebral disc degeneration.