Subcutaneous rupture of the Achilles tendon: basic science and some aspects of clinical practice

Stem Cells from Healthy and Tendinopathic Human Tendons: Morphology, Collagen and Cytokines Expression and Their Response to T3 Thyroid Hormone

The aim of this study was to investigate the effect of triiodothyronine (T3) on tendon specific markers and cytokines expression of stem cells extracted from human tendons. Indeed, thyroid hormones have been reported to be protective factors, maintaining tendons’ homeostasis, whereas tendinopathy is believed to be related to a failed healing response. Healthy and tendinopathic human tendons were harvested to isolate tendon stem/progenitor cells (TSPCs). TSPCs obtained from pathological samples showed gene expression and morphological modifications at baseline in comparison with cells harvested from healthy tissues. When cells were maintained in a medium supplemented with T3 (10⁻⁶ M), only pathological populations showed a significant upregulation of tenogenic markers (DCN, TNC, COL1A1, COL3A1). Immunostaining revealed that healthy cells constantly released type I collagen, typical of tendon matrix, whereas pathological ones overexpressed and secreted type III collagen, typical of scarred and impaired tissue. Pathological cells also overexpressed pro- and anti-inflammatory cytokines, suggesting an impaired balance in the presence of T3, without STAT3 activation. Moreover, DKK-1 was significantly high in the culture medium of pathological cell cultures and was reversed by T3. This study opens perspectives on the complex biochemical alteration of cells from pathological tendons, which may lead to the chronic disease context with an impaired extracellular matrix.

Comparative analysis of Achilles tendon healing outcomes after open tenotomy versus percutaneous tenotomy: An experimental study in rats

There is growing interest in conservative treatment of Achilles tendon rupture. However, the majority of experimental studies of Achilles tendon have been performed by open tenotomy. More appropriate model of conservative treatment of Achilles tendon rupture is required. We performed an experimental study to evaluate whether outcomes differ between open tenotomy and percutaneous tenotomy of the Achilles tendon in rats. The Achilles tendons of 48 rats were transected. The animals were divided into two groups according to surgical technique: open tenotomy or microscopy-assisted percutaneous tenotomy. After 1, 2, and 4 weeks, functional, biomechanical, and histological analyses were performed. Western blot was performed for quantitative molecular analysis at 1 week. The Achilles functional index was superior in the percutaneous tenotomy group, compared with the open tenotomy group, at 1 week. The cross-sectional area was significantly larger in the percutaneous tenotomy group than in the open tenotomy group at 4 weeks. Relative to the native tendons, load to failure and stiffness yielded comparable results at 2 weeks in the percutaneous tenotomy group and at 4 weeks in the open tenotomy group. The histological score was significantly better in the percutaneous tenotomy group than in the open tenotomy group at 1 week. At 1 week, interleukin-1β expression in the open tenotomy group was higher than in the percutaneous tenotomy group. In summary, Achilles tendon healing was substantially affected by the tenotomy method. We presume that our percutaneous tenotomy method might constitute a useful experimental animal model for conservative treatment of Achilles tendon rupture.

Biomechanical comparisons of three minimally invasive Achilles tendon percutaneous repair suture techniques

BACKGROUND

While no gold standard exists for the management of Achilles tendon ruptures, surgical repair is common in healthy and active patients. Minimally invasive repair methods have become increasingly popular, while biomechanical equivalency hasn't been proven yet.

METHODS

A mid-substance Achilles tendon rupture was created 6 cm proximal to the calcaneal insertion in 27 fresh-frozen cadaveric ankles. Specimens were randomly allocated to 1 of 3 repair techniques: Huttunen et al. (2014) (1) PARS Achilles Jig System, Nyyssönen et al. (2008) (2) Achilles Midsubstance SpeedBridge™, Schipper and Cohen (2017) (3) Dresdner Instrument and subsequently subjected to cyclic loading with 250 cycles each at 1 Hz with 4 different loading ranges (20-100 N, 20-200 N, 20-300 N, and 20-400 N).

FINDINGS

After 250 cycles no significant differences in elongation were observed between PARS and Dresdner Instrument(p = 1.0). Furthermore, SpeedBridge™ repairs elongated less than either Dresdner Instrument (p = 0.0006) or PARS (p = 0.102). Main elongation (85%) occurred within the first 10 cycles with a comparable elongation in between 10 and 100 and 100-250 cycles. While all repairs withstood the first 250 cycles of cyclic loading from 20 to 100 N, only the PARS (468 ± 175) and Midsubstance SpeedBridge™ (538 ± 208) survived more cycles. Within all 3 groups suture cut out was seen to be the most common failure mechanism.

INTERPRETATION

Within all groups early repair elongation was seen. While this was least obvious within the SpeedBridge™ technique, ultimate strengths of repairs (cycles to failure) were comparable across PARS and SpeedBridge™ with a decline in the Dresdner Instrument group.

A multiscale study of morphological changes in tendons following repeated cyclic loading

The response of white New Zealand rabbit Achilles tendons to load was assessed using mechanical measures and confocal arthroscopy (CA). The progression of fatigue-loading-induced damage of the macro- (tenocyte morphology, fiber anisotropy and waviness), as well as the mechanical profile, were assessed within the same non-viable intact tendon in response to prolonged cyclic and static loading (up to four hours) at different strain levels (3%, 6% and 9%). Strain-mediated repeated loading induced a significant decline in mechanical function (p < 0.05) with increased strain and cycles. Mechanical and structural resilience was lost with repeated loading (p < 0.05) at macroscales. The lengthening of D-periodicity correlated strongly with the overall tendon mechanical changes and loss of spindle shape in tenocytes. This is the first study to provide a clear concurrent assessment of form (morphology) and function (mechanics) of tendons undergoing different strain-mediated repeated loading at multiple-scale assessments. This study identifies a variety of multiscale properties that may contribute to the understanding of mechanisms of tendon pathology.

Detection of Type I and III collagen in porcine acellular matrix using HPLC-MS

Acellular matrix (ACM) has been widely used as a biomaterial. As the main component of ACM, collagen type and content show influence on the material properties. In this research, the collagen in ACM from different tissues of pig were determined by detection of marker peptides. The marker peptides of Type I and III collagen were identified from the digested collagen standards using ions trap mass spectrometry (LCQ). The relationship between the abundance of marker peptide and collagen concentration was established using triple quadrupole mass spectrometer (TSQ). The contents of Type I and III collagen in ACM from different tissues were determined. The method was further verified by hydroxyproline determination. The results showed that, the sum of Type I and III collagen contents in the ACM from small intestinal submucosa, dermis and Achilles tendon of pig were about 87.59, 81.41 and 61.13%, respectively, which were close to the total collagen contents in these tissues. The results proved that this method could quantitatively detect the collagen with different types in the ACM of various tissues.

Return to football training and competition after lockdown caused by the COVID-19 pandemic: medical recommendations

The lockdown caused by the COVID-19 pandemic represents a great unknown regarding the physiological changes induced in elite football players. Although it will differ from country to country, the return to sport for professional football players will follow a forced lockdown never experienced and longer than the normal annual season break. Moreover, in addition to an obvious decrease in performance, the lockdown will possibly lead to an increase of the injury risk. In fact, preseason is always a period with a specific football injury epidemiology, with an increase in the incidence and prevalence of overuse injuries. Therefore, it seems appropriate to recommend that specific training and injury prevention programmes be developed, with careful load monitoring. Training sessions should include specific aerobic, resistance, speed and flexibility training programmes. The aerobic, resistance and speed training should respect some specific phases based on the progressiveness of the training load and the consequent physiological adaptation response. These different phases, based on the current evidence found in the literature, are described in their practical details. Moreover, injury prevention exercises should be incorporated, especially focusing on overuse injuries such as tendon and muscle lesions. The aim of this paper is to provide practical recommendations for the preparation of training sessions for professional footballers returning to sport after the lockdown.

Tendon lengthening after achilles tendon rupture-passive effects on the ankle joint in a cadaveric pilot study simulating weight bearing

BACKGROUND

In recent years, primary Achilles tendon ruptures have increased due to the aging population's participation in physically demanding activities. These injuries commonly occur during recreational sports and frequently lead to a long-term reduction in activity despite treatment. Non-operative methods of treatment for Achilles tendon ruptures may result in the Achilles healing in a lengthened position compared to the pre-injury state. This study uses a cadaveric model that simulates static weight bearing to explore the effect of a lengthened Achilles tendon on ankle joint load distribution.

METHODS

Five lower limb cadaveric specimens were placed on a custom jig, where a 334 N (75 lb) load was applied at the femoral head, and the foot was supported against a plate to simulate static double-leg stance. A pressure mapping sensor was inserted into the ankle joint. A percutaneous triple hemiresection tendo-Achilles lengthening procedure (Hoke procedure) was performed on each specimen to simulate tendon lengthening after conservative treatment. Contact pressure, peak pressure, and center-of-pressure were measured for native and tendon-lengthened conditions.

RESULTS

Tendon rupture did not significantly alter average contact pressure, peak contact pressures, or center-of-pressure in the ankle joint compared with native tendon.

CONCLUSION

Achilles lengthening does not significantly change contact pressures of the ankle joint in this model . This result suggests that the passive restraint on ankle joint translation imposed by the Achilles tendon is minimal without muscle activation.

Patients with Achilles Tendon Rupture Have a Degenerated Contralateral Achilles Tendon: An Elastography Study

Purpose

To evaluate differences of Achilles tendon (AT) hardness and morphology between asymptomatic tendons in patients with acute AT ruptures on the contralateral side and asymptomatic tendons in healthy people by using computer-assisted quantification on axial-strain sonoelastography (ASE).

Methods

The study consisted of 33 asymptomatic tendons in 33 patients (study group) and 34 tendons in 19 healthy volunteers (control group). All the tendons were examined by both ASE and conventional ultrasound. Computer-assisted quantification on ASE was applied to extract hardness variables, including the mean (Hmean), 20^th percentile (H20), median (H50) and skewness (Hsk) of the hardness within tendon, and the ratio of the mean hardness within tendon to that outside tendon (Hratio) and three morphological variables: the thickness (THK), cross-sectional area, and eccentricity (ECC) of tendons.

Results

The Hmean, Hsk, H20, H50, and Hratio in the proximal third of the tendon body in study group were significantly smaller than those in control group (Hmean: 0.43±0.09 vs 0.50±0.07, p=0.001; Hsk: -0.53±0.51 vs -1.09±0.51, p<0.001; H20: 0.31±0.10 vs 0.40±0.10, p=0.001; H50: 0.45±0.10 vs 0.53±0.08, p<0.001; Hratio: 1.01±0.25 vs 1.20±0.23, p=0.003). The THK and cross-sectional area of tendons in the study group were larger than those in the control group (p<0.05).

Conclusions

As a quantitative objective method, the computer-assisted ASE reveals that the asymptomatic ATs contralateral to acute rupture are softer than those of healthy control group at the proximal third and the asymptomatic tendons in people with rupture history are thicker, larger, and rounder than those of normal volunteers especially at the middle and distal thirds of AT body.

Overuse injuries in sport: a comprehensive overview

BACKGROUND

The absence of a single, identifiable traumatic cause has been traditionally used as a definition for a causative factor of overuse injury. Excessive loading, insufficient recovery, and underpreparedness can increase injury risk by exposing athletes to relatively large changes in load. The musculoskeletal system, if subjected to excessive stress, can suffer from various types of overuse injuries which may affect the bone, muscles, tendons, and ligaments.

METHODS

We performed a search (up to March 2018) in the PubMed and Scopus electronic databases to identify the available scientific articles about the pathophysiology and the incidence of overuse sport injuries. For the purposes of our review, we used several combinations of the following keywords: overuse, injury, tendon, tendinopathy, stress fracture, stress reaction, and juvenile osteochondritis dissecans.

RESULTS

Overuse tendinopathy induces in the tendon pain and swelling with associated decreased tolerance to exercise and various types of tendon degeneration. Poor training technique and a variety of risk factors may predispose athletes to stress reactions that may be interpreted as possible precursors of stress fractures. A frequent cause of pain in adolescents is juvenile osteochondritis dissecans (JOCD), which is characterized by delamination and localized necrosis of the subchondral bone, with or without the involvement of articular cartilage. The purpose of this compressive review is to give an overview of overuse injuries in sport by describing the theoretical foundations of these conditions that may predispose to the development of tendinopathy, stress fractures, stress reactions, and juvenile osteochondritis dissecans and the implication that these pathologies may have in their management.

CONCLUSIONS

Further research is required to improve our knowledge on tendon and bone healing, enabling specific treatment strategies to be developed for the management of overuse injuries.

Achilles Tendinopathy

Achilles tendinopathy is a common cause of disability. Despite the economic and social relevance of the problem, the causes and mechanisms of Achilles tendinopathy remain unclear. Tendon vascularity, gastrocnemius-soleus dysfunction, age, sex, body weight and height, pes cavus, and lateral ankle instability are considered common intrinsic factors. The essence of Achilles tendinopathy is a failed healing response, with haphazard proliferation of tenocytes, some evidence of degeneration in tendon cells and disruption of collagen fibers, and subsequent increase in noncollagenous matrix. Tendinopathic tendons have an increased rate of matrix remodeling, leading to a mechanically less stable tendon which is more susceptible to damage. The diagnosis of Achilles tendinopathy is mainly based on a careful history and detailed clinical examination. The latter remains the best diagnostic tool. Over the past few years, various new therapeutic options have been proposed for the management of Achilles tendinopathy. Despite the morbidity associated with Achilles tendinopathy, many of the therapeutic options described and in common use are far from scientifically based. New minimally invasive techniques of stripping of neovessels from the Kager's triangle of the tendo Achillis have been described, and seem to allow faster recovery and accelerated return to sports, rather than open surgery. A genetic component has been implicated in tendinopathies of the Achilles tendon, but these studies are still at their infancy.

Fluoroquinolones and the Risk of Achilles Tendon Disorders: Update on a Neglected Complication

OBJECTIVE

To evaluate the current evidence and to identify associated risk factors that increase the incidence of this complication. Fluoroquinolone (FQ) has been considered the first-line therapy for uncomplicated urinary infections. FQ has been associated with Achilles tendon disorders, especially during the first month of treatment.

METHODS

Data sources searched included PubMed, MEDLINE, and Scopus from January 1988 to June 2017.

RESULTS

A total of 79 articles were used, with ciprofloxacin representing the most common drug.

CONCLUSION

We found that male gender, advanced age, normal body mass index, chronic renal failure, and concurrent use of corticosteroids increase the risk of Achilles tendon disorders.

Experimental model of Achilles tendon injury in rats

PURPOSE

To describe an effective experimental model to study the Achilles tendon healing.

METHODS

Forty male Rattus norvegicus albinus, Wistar lineage adult male weighing 250 to 300g were used for this experiment and thirty were surgically submitted to bilateral partial transverse section of the Achilles tendon. The right tendon was treated with radio waves (RF) whereas the left tendon served as control. On the third postoperative day, the rats were divided into four experimental groups consisting of ten rats each which were treated with monopolar RF adjusted to 650 kHz and 2w, for two minutes twice a week and a group of normal animals without any intervention, until they were sacrificed on the 7th, 14th and 28th days, respectively. Tendons were weighed and collagen quantification was evaluated by hydroxyprolin content.

RESULTS

Significant reduction in collagen content on day 7, 14 and 28 was related to control experiment to normal tendon (7 days, p<0.01; 14 e 28 days, p<0.05).

CONCLUSION

The experimental model has been effective and available to be used to study Achilles tendon healing.

Fluoroquinolones impair tendon healing in a rat rotator cuff repair model: a preliminary study

BACKGROUND

Recent studies suggest that fluoroquinolone antibiotics predispose tendons to tendinopathy and/or rupture. However, no investigations on the reparative capacity of tendons exposed to fluoroquinolones have been conducted.

HYPOTHESIS

Fluoroquinolone-treated animals will have inferior biochemical, histological, and biomechanical properties at the healing tendon-bone enthesis compared with controls.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ninety-two rats underwent rotator cuff repair and were randomly assigned to 1 of 4 groups: (1) preoperative (Preop), whereby animals received fleroxacin for 1 week preoperatively; (2) pre- and postoperative (Pre/Postop), whereby animals received fleroxacin for 1 week preoperatively and for 2 weeks postoperatively; (3) postoperative (Postop), whereby animals received fleroxacin for 2 weeks postoperatively; and (4) control, whereby animals received vehicle for 1 week preoperatively and for 2 weeks postoperatively. Rats were euthanized at 2 weeks postoperatively for biochemical, histological, and biomechanical analysis. All data were expressed as mean ± standard error of the mean (SEM). Statistical comparisons were performed using either 1-way or 2-way ANOVA, with P < .05 considered significant.

RESULTS

Reverse transcriptase quantitative polymerase chain reaction (RTqPCR) analysis revealed a 30-fold increase in expression of matrix metalloproteinase (MMP)-3, a 7-fold increase in MMP-13, and a 4-fold increase in tissue inhibitor of metalloproteinases (TIMP)-1 in the Pre/Postop group compared with the other groups. The appearance of the healing enthesis in all treated animals was qualitatively different than that in controls. The tendons were friable and atrophic. All 3 treated groups showed significantly less fibrocartilage and poorly organized collagen at the healing enthesis compared with control animals. There was a significant difference in the mode of failure, with treated animals demonstrating an intrasubstance failure of the supraspinatus tendon during testing. In contrast, only 1 of 10 control samples failed within the tendon substance. The healing enthesis of the Pre/Postop group displayed significantly reduced ultimate load to failure compared with the Preop, Postop, and control groups. There was no significant difference in load to failure in the Preop group compared with the Postop group. Pre/Postop animals demonstrated significantly reduced cross-sectional area compared with the Postop and control groups. There was also a significant reduction in area between the Preop and control groups.

CONCLUSION

In this preliminary study, fluoroquinolone treatment negatively influenced tendon healing.

CLINICAL RELEVANCE

These findings indicate that there was an active but inadequate repair response that has potential clinical implications for patients who are exposed to fluoroquinolones before tendon repair surgery.

Mini-open tenorrhaphy of acute Achilles tendon ruptures: medium-term follow-up of 100 cases

BACKGROUND

The high incidence of soft tissue complications related to open Achilles repair has driven enthusiasm for developing minimally invasive surgical procedures. The Dresden procedure, which reduces wound-healing issues and avoids sural nerve damage, has recently been published and shows good functional results.

OBJECTIVE

To evaluate medium-term clinical results of procedures using the Dresden mini-open technique on acute Achilles tendon ruptures.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective analysis was performed on 100 consecutive patients with a mean follow-up of 42.1 months. At follow-up, the American Orthopaedic Foot and Ankle Society (AOFAS) score, time to return to work and sports, subjective satisfaction, and complications were registered. An isokinetic test was performed on the first 21 patients of this series at 1 year postoperatively.

RESULTS

The mean time to return to work was 56.0 days, and the mean time to return to sports was 18.9 weeks. The mean AOFAS score was 97.7; 98% of patients were satisfied. No complications regarding soft tissues and sural nerve damage were reported. Two reruptures and 5 cases of deep venous thrombosis were observed. The isokinetic evaluation showed good recovery of the involved muscles.

CONCLUSION

The excellent functional and satisfaction results, ease of the procedure, and avoidance of sural nerve damage make the mini-open technique a very attractive alternative for acute, spontaneous Achilles tendon ruptures.

Review article: Treatment for Achilles tendon ruptures in athletes

Treatment for Achilles tendon ruptures in athletes is controversial. Surgical fixation has lower rates of re-rupture and confers increased strength and function, whereas conservative treatment has lower risks of wound complications. We review the literature on the optimal treatment for Achilles tendon rupture in athletes.

The rate of sural nerve violation using the Achillon device: a cadaveric study

BACKGROUND

Management of acute Achilles tendon rupture remains controversial. Open repair results in lower rerupture rates but is associated with complications from wound healing. Percutaneous and limited open repairs minimize soft tissue complications; however, there is a theoretical increased risk of sural nerve injury. We evaluated the risk of sural nerve violation with the Achillon limited open repair device in cadavers.

METHODS

This cadaveric study consisted of 2 parts. The first part evaluated the frequency and location of sural nerve violation using the standard Achillon protocol in 18 intact embalmed left lower limbs. The second part involved device manipulation with 30 degrees of either internal or external rotation in 13 paired, intact embalmed lower limbs.

RESULTS

In the first part, 5 of 18 specimens had at least 1 suture passing through the sural nerve. Eight of the 54 needle passes (14.8%) directly pierced the substance of the sural nerve. With internal rotation, 8 of 13 specimens had at least 1 violation of the nerve. Ten of the 39 needle passes (25.6%) directly pierced the substance of the sural nerve. With external rotation, no nerves were violated, significantly decreasing the risk of sural nerve violation versus neutral (P = .038) and internal rotation (P = .001). When sural nerve violation was evaluated in regard to instrument outlet, there was a higher risk in the proximal needle passer (outlet no. 3) compared with the distal needle passer (outlet no. 1) with both neutral testing and internal rotation (P = .027).

CONCLUSION

This study demonstrated the potential risk for sural nerve injury using the Achillon device.

CLINICAL RELEVANCE

External rotation of the Achillon decreased the rate of sural nerve violation. This may optimize its use in Achilles tendon repairs.

Acute achilles tendon rupture in athletes

The incidence of AT rupture has increased in recent decades. AT ruptures frequently occur in the third or fourth decade of life in sedentary individuals who play sport occasionally. Ruptures also occur in elite athletes. Clinical examination must be followed by imaging. Conservative management and early mobilization can achieve excellent results, but the rerupture rate is not acceptable for the management of young, active, or athletic individuals. Open surgery is the most common option for AT ruptures, but there are risks of superficial skin breakdown and wound problems. These problems can be prevented with percutaneous repair.

Severe shoulder tendinopathy associated with levofloxacin

Fluoroquinolone (FQ)-associated tendinopathy and myopathy are uncommon but well recognized complications of the use of this class of antibacterial agents. The case of a 63-year-old previously asymptomatic female patient who developed severe left shoulder tendinopathy after surreptitiously doubling the prescribed dose of levofloxacin for the treatment of community-acquired pneumonia is reported here. Surgical stabilization with suture anchors and subacromial decompression were needed.

Extracorporeal Shock Wave Treatment (ESWT) improves in vitro functional activities of ruptured human tendon-derived tenocytes

In vitro models of human tenocytes derived from healthy as well as from ruptured tendons were established, characterized and used at very early passage (P1) to evaluate the effects of Extracorporeal Shock Wave Treatment (ESWT). The molecular analysis of traditional tenocytic markers, including Scleraxis (Scx), Tenomodulin (Tnm), Tenascin-C (Tn-C) and Type I and III Collagens (Col I and Col III), permitted us to detect in our samples the simultaneous expression of all these genes and allowed us to compare their levels of expression in relationship to the source of the cells and treatments. In untreated conditions, higher molecular levels of Scx and Col I in tenocytes from pathological compared to healthy samples have been detected, suggesting – in the cells from injured tendon – the natural trigger of an early differentiation and repairing program, which depends by Scx and requires an increase in collagen expression. When ESWT (at the dose of 0.14 mJ/mm²) was applied to cultured tenocytes explanted from injured source, Scx and Col I were significantly diminished compared to healthy counterpart, indicating that such natural trigger maybe delayed by the treatment, in order to promote cellular repair. Herein, we show for the first time that ESWT enhances in vitro functional activities of ruptured tendon-derived tenocytes, such as proliferation and migration, which could probably contributes to tendon healing in vivo.

Non-immortalized human tenocyte cultures as a vehicle for understanding cellular aspects to tendinopathy

The biochemical mechanisms underlying tendinopathy are obscure. We briefly describe preliminary observations of human tenocyte behaviour in culture as a vehicle for determining the role of reactive oxygen in tendon pathology.

Functional management of Achilles tendon rupture: A viable option for non-operative management

BACKGROUND

Functional management of the ruptured Achilles tendon can be effective using orthoses like the removable walker boot (Foam Walker Boot, Air Cast UK Limited, Lincolnshire, United Kingdom). We conducted this study to look at the outcome of our protocol using this orthosis.

MATERIALS AND METHODS

We retrospectively reviewed 107 non-operatively managed Achilles tendon ruptures over the last 5 years. Case notes were analyzed for demographics and immediate outcomes. Long term outcomes were assessed by a postal questionnaire using the Achilles Tendon Total Rupture Score (ATRS).

RESULTS

Of the 107 tendons (male:female=71:36, mean age=50 years), 105 tendons (98%) healed with an average discharge time of 22 weeks. Six patients reported major complications and 6 reported minor complications. We received 56 questionnaires with a mean ATRS score of 21. Seventy-seven percent returned to pre-injury level of activity.

CONCLUSION

Functional management of Achilles tendon rupture, under appropriate supervision, provides a viable option for non-operative management.

Favorable outcome of percutaneous repair of achilles tendon ruptures in the elderly

Percutaneous repair of Achilles tendon (AT) ruptures reportedly reduces the risk of rerupture compared to nonoperative treatment and reduces the risk of wound infection compared to open surgery. We retrospectively reviewed the postoperative Achilles tendon total rupture score (ATRS), and the maximum calf circumference in 35 patients over 65 years of age who sustained an acute tear of the AT and underwent percutaneous repair of the AT. There were 26 men and nine women with a mean age at operation of 73.4 +/- 8.7 years (range, 65-86 years). Of the 35 recruited patients, we report on 27 patients for whom we have a full data set. The minimum followup was 49 months (mean, 88 months; range, 49-110 months). The ATRS had a postoperative average rating of 69.4 +/- 14 (range, 56-93). All patients were able to bear weight fully on the affected limb by the eighth postoperative week. The data suggest that percutaneous repair of the AT is a suitable option for patients older than 65, producing similar outcomes when compared to percutaneous repair in younger patients of previous reports.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Acute ruptures of the achilles tendon

The Achilles tendon (AT) is the most frequently ruptured tendon in the human body, but the etiology of AT ruptures is still not completely understood. Percutaneous repair and conservative management are viable alternatives to open surgery, which carries higher complication rates and is the most costly of the 3 management options. Individual patients will have different needs due to their age, occupation, or level of sporting activity. If the studies reporting a rising incidence of AT rupture are accurate, the field of AT surgery will become an increasingly important one for orthopedic surgeons. A major problem in the evaluation of the outcome of management of AT ruptures has been the lack of a universally accepted scoring system for the evaluation of results of management of AT rupture. The AT Total Rupture Score is a self-administered instrument with high clinical utility, and it can be used for measuring the outcome, related to symptoms and physical activity, after treatment in patients with a total AT rupture. Future developments may include the use of adhesives in tendon surgery. An understanding of the role, which cytokines play in tendon healing may also lead to the advent of new treatments, possibly based on gene therapy. However, such novel interventions are unlikely to be in routine clinical use for some time.

The regulation of aggrecanase ADAMTS-4 expression in human Achilles tendon and tendon-derived cells

Several members of the ADAMTS (A Disintegrin And Metalloproteinase with ThromboSpondin motifs) family have been identified as aggrecanases, whose substrates include versican, the principal large proteoglycan in the tendon extracellular matrix. We have characterized the expression of ADAMTS-4 in human Achilles tendon and tendon-derived cells. ADAMTS-4 mRNA levels were higher in ruptured tendon compared with normal tendon or chronic painful tendinopathy. In tissue extracts probed by Western blotting, mature ADAMTS-4 (68 kDa) was detected only in ruptured tendons, while processed ADAMTS-4 (53 kDa) was detected also in chronic painful tendinopathy and in normal tendon. In cultured Achilles tendon cells, transforming growth factor-β (TGF-β) stimulated ADAMTS-4 mRNA expression (typically 20-fold after 24 h), while interleukin-1 induced a smaller, shorter-term stimulation which synergised markedly with that induced by TGF-β. Increased levels of immunoreactive proteins consistent with mature and processed forms of ADAMTS-4 were detected in TGF-β-stimulated cells. ADAMTS-4 mRNA was expressed at higher levels by tendon cells in collagen gels than in monolayer cultures. In contrast, the expression of ADAMTS-1 and -5 mRNA was lower in collagen gels compared with monolayers, and these mRNA showed smaller or opposite responses to growth factors and cytokines compared with that of ADAMTS-4 mRNA. We conclude that both ADAMTS-4 mRNA and ADAMTS-4 protein processing may be differentially regulated in normal and damaged tendons and that both the matrix environment and growth factors such as TGF-β are potentially important factors controlling ADAMTS aggrecanase activities in tendon pathology.

Fluoroquinolone-associated tendinopathy: a case report

Fluoroquinolone-associated tendinopathy is well described. This adverse effect however does not appear to be widely known among medical practitioners. We hereby described a case of ciprofloxacin-associated tendinopathy for which the adverse drug reaction was not suspected initially and the patient was inappropriately reassured and incorrectly advised to complete the antibiotic course. Given the frequent use of fluoroquinolones in clinical practice and the potential for severe disability from tendon rupture, we consider it important to remind your readers of this uncommon but potentially devastating adverse drug reaction.

Evidence of tendinitis provoked by fluoroquinolone treatment: a case-control study

OBJECTIVE

To investigate the association between the use of fluoroquinolone agents and the risk of tendinitis in a large population-based case-control study.

METHODS

The study was performed by linking automated health databases from the Region of Lombardia, Italy. Cases were patients aged > or =18 years who had a hospital discharge diagnosis of non-traumatic tendinitis in 2002-3. For each case, up to five controls were randomly selected among those eligible for inclusion in the study. A conditional logistic regression model was used to estimate the odds ratio of tendinitis associated with the current, recent and past use of fluoroquinolones. Odds ratios were adjusted for exposure to other antibacterials and other drugs.

RESULTS

22,194 cases and 104,906 controls met the inclusion criteria. Current use of fluoroquinolones significantly increased the risk of tendon disorders as a whole (odds ratio [OR] = 1.7; 95% CI 1.4, 2.0), tendon rupture (OR = 1.3; 95% CI 1.0, 1.8) and rupture of the Achilles' tendon (OR = 4.1; 95% CI 1.8, 9.6). Concomitant use of corticosteroids and fluoroquinolones increased the risk of both tendon rupture (OR = 3.1; 95% CI 1.5, 6.3) and rupture of the Achilles' tendon (OR = 43.2; 95% CI 5.5, 341.1).

DISCUSSION

Evidence that exposure to fluoroquinolones is associated with the sudden occurrence of tendinitis is supported by this large population-based study. We can estimate that a single case of rupture of the Achilles' tendon would occur for every 5958 persons treated with fluoroquinolones (95% CI 2148, 23,085). The corresponding number needed to harm is 979 (95% CI 122, 9172) for patients who concomitantly use corticosteroids and 1638 (95% CI 351, 8843) for those aged >60 years.

CONCLUSION

Clinicians should be aware of this adverse effect, and the increased risk for fluoroquinolone-associated tendinitis in elderly patients with corticosteroid use must be considered when these agents are prescribed.

Use of ultrasound to identify chronic Achilles tendinosis in an active asymptomatic population

OBJECTIVES

The aim of the study was to identify the prevalence of degenerative change in the Achilles tendons of currently asymptomatic individuals and correlate it with their degree of physical activity.

METHODS

We recruited 126 healthy subjects, mean age 33.1, range 20 - 50 (78 males and 48 females). Their levels of physical activity were assessed by a questionnaire and scored using the Allied Dunbar Fitness Survey criteria, modified to exclude non-weight bearing activity. One investigator, who was blinded to the activity levels, ultrasound scanned all 252 tendons. Tendons were examined for evidence of hypoechoic regions, localised fusiform thickening, and the cross-sectional diameter of each was measured.

RESULTS

Overall 59% (149) of tendons had ultrasound evidence of hypoechoic regions. In 50 tendons (in 31 patients) there was a history of previous Achilles pain and 84% of these had hypoechoic regions. Thirty three percent of subjects in the lowest quartile of activity had evidence of hypoechoic regions compared to 72.6% in the most active quartile (Pearson Chi2 p < 0.01). Only 5.6% of all Achilles tendons had ultrasound evidence of localised fusiform thickening, with none in the inactive group compared to 6.4% in the very active group (Pearson Chi2 p = 0.03).

CONCLUSIONS

Degenerative changes, identified by ultrasound, are common in the Achilles tendon and are often asymptomatic. There is a direct relationship between these changes and levels of current and lifetime activity. The natural history of asymptomatic chronic Achilles tendinosis and their relationship to future pain or tendon pathology is unknown.

Diagnosis and imaging of ankle instability

Ankle instability is a major cause of symptoms following an ankle sprain. With a thorough history and examination, appropriate additional investigations, including cross-sectional imaging, and thoughtful interpretation of the information, one should rarely be caught out by misdiagnosis, multiple diagnoses, or unusual causes.

Phenotypic Drift in Human Tenocyte Culture

Tendon ruptures are increasingly common, repair can be difficult, and healing is poorly understood. Tissue engineering approaches often require expansion of cell numbers to populate a construct, and maintenance of cell phenotype is essential for tissue regeneration. Here, we characterize the phenotype of human Achilles tenocytes and assess how this is affected by passaging. Tenocytes, isolated from tendon samples from 6 patients receiving surgery for rupture of the Achilles tendon, were passaged 8 times. Proliferation rates and cell morphology were recorded at passages 1, 4, and 8. Total collagen, the ratio of collagen types I and III, and decorin were used as indicators of matrix formation, and expression of the integrin beta1 subunit as a marker of cell-matrix interactions. With increasing passage number, cells became more rounded, were more widely spaced at confluence, and confluent cell density declined from 18,700/cm2 to 16,100/cm2 ( p = 0.009). No change to total cell layer collagen was observed but the ratio of type III to type I collagen increased from 0.60 at passage 1 to 0.89 at passage 8 ( p < 0.001). Decorin expression significantly decreased with passage number, from 22.9 +/- 3.1 ng/ng of DNA at passage 1, to 9.1 +/- 1.8 ng/ng of DNA at passage 8 ( p < 0.001). Integrin expression did not change. We conclude that the phenotype of tenocytes in culture rapidly drifts with progressive passage.

Achilles tendon rupture and its association with fluoroquinolone antibiotics and other potential risk factors in a managed care population

BACKGROUND

Case reports and observational studies have implicated fluoroquinolone antibiotic exposure as a risk factor for Achilles tendon rupture (ATR), an uncommon condition for which there are few formal studies. We sought to quantify the strength of association between exposure to fluoroquinolone antibiotics and the occurrence of ATR, accounting for other risk factors.

METHODS

This was a case-control study nested within a health insurer cohort. Cases of ATR were identified and confirmed using patterns of health insurance claims that were validated through sampled medical record review. Information on risk factors, including fluoroquinolone exposure, came from health insurance claims.

RESULTS

There were 947 cases of ATR and 18 940 controls. A dispensing of a fluoroquinolone antibiotic in the past 6 months was more common among ATR cases than controls, although not significantly so (odds ratio (OR) = 1.2; 95% confidence interval (CI) = 0.9-1.7), and exposure to a higher cumulative fluoroquinolone dose was more strongly associated (OR = 1.5, 95%CI = 1.0-2.3). Other risk factors for ATR were trauma (OR = 17.2, 95%CI = 14.0-20.2), male sex (OR = 3.0, 95%CI = 2.6-3.5), injected corticosteroid administration (OR = 2.2, 95%CI = 1.6-2.9), obesity (OR = 2.0, 95%CI = 1.2-3.1), rheumatoid arthritis (OR = 1.9, 95%CI = 1.0-3.7), skin or soft tissue infections (OR = 1.5, 95%CI = 0.9-2.3), oral corticosteroids (OR = 1.4, 95%CI = 1.0-1.8), and non-fluoroquinolone antibiotics (OR = 1.2, 95%CI = 1.1-1.5).

CONCLUSIONS

The elevation in ATR risk associated with fluoroquinolones was similar in magnitude to that associated with oral corticosteroids or non-fluoroquinolone antibiotics. Trauma and male sex were more strongly associated with ATR, as were obesity and injected corticosteroids.

Bilateral Achilles tendon rupture: a case report

Bilateral Achilles tendon rupture is a rare injury. We present a case of a 59-year-old gentleman who sustained a bilateral Achilles tendon rupture when the tendon was subjected to normal physiological load. He was treated operatively with V-Y plasty and repair of the tendon with post-operative plaster immobilisation.

Fluoroquinolones and tendon disorders

Fluoroquinolones are the most potent oral antibiotics in clinical use today. Increasingly, these drugs are being prescribed for relatively benign infections and for new categories of patients, including paediatric patients. As their use becomes more frequent, so will the adverse events. This review focuses on a rare but debilitating adverse reaction, the fluoroquinolone-associated tendinopathy. Despite many published case reports and approximately 3500 cases reported to the World Health Organization Collaborating Centre for Drug Monitoring, little is known about the mechanisms behind this fluoroquinolone-specific toxicity. Data on chemical properties, mode of action, pharmacokinetic features, clinical presentation and risk factors in relation to tendon toxicity are discussed and the literature reviewed. As long as the musculoskeletal toxicity cannot be predicted by in vitro or in vivo models and this class of antibiotics is one of the most commonly linked to selection of resistant bacteria, a more prudent use of fluoroquinolones is warranted.

Ankle joint proprioception and passive mechanical properties of the calf muscles after an Achilles tendon rupture: a comparison with matched controls

OBJECTIVE

To examine if ankle joint proprioception, passive stiffness, and torque relaxation responses of the involved and uninvolved limbs of persons with a previous history of an Achilles tendon rupture were different from matched controls.

DESIGN

Quasi-experimental mixed design.

BACKGROUND

The influence of an Achilles tendon rupture on the proprioceptive and kinetic performance of the involved and uninvolved ankle is not known.

METHODS

Twenty persons (mean age, 44.8 years) with a unilateral rupture and 20 matched controls (mean age, 44.2 years) volunteered. Proprioception was tested with a position-matching protocol from which absolute errors were quantified. A dynamometer was used to measure ankle joint angle and passive torque from which stiffness and torque relaxation were calculated.

RESULTS AND CONCLUSIONS

Proprioception absolute errors for the involved and uninvolved limbs of the experimental group were 27% and 31% greater respectively, than values for the control group. Torque relaxation values were greater in the involved limb versus the uninvolved limb or the control group (P=0.003-0.04). In conclusion, participants with a previous history of an Achilles tendon rupture display proprioception deficits in both limbs and greater torque relaxation in the involved limb in comparison to matched controls.

RELEVANCE

Bilateral deficits in ankle joint proprioception, as reported in this study, suggest the uninvolved limb may not serve as an effective control and because proprioception deficits influence some functional tests, Achilles tendon rupture patients may benefit from proprioception training.

Fluoroquinolone-associated tendinopathy: a critical review of the literature

With the expanded use of fluoroquinolones for the treatment of community-acquired respiratory infections and reports of tendon injury linked to the use of these agents, we reviewed the literature to investigate the frequency and strength of this association. Ninety-eight case reports were available for review. The incidence of tendon injury associated with fluoroquinolone use is low in a healthy population but increases in patients who have renal dysfunction, who are undergoing hemodialysis, or who have received renal transplants. Pefloxacin and ciprofloxacin were most frequently implicated, but tendon injury was reported with most fluoroquinolones. The median duration of fluoroquinolone treatment before the onset of tendon injury was 8 days, although symptoms occurred as early as 2 hours after the first dose and as late as 6 months after treatment was stopped. Up to one-half of patients experienced tendon rupture, and almost one-third received long-term corticosteroid therapy. Tendon injury associated with fluoroquinolone use is significant, and risk factors such as renal disease or concurrent corticosteroid use must be considered when these agents are prescribed.

Management of Achilles tendinopathy by ultrasound-guided percutaneous tenotomy

PURPOSE

To report the middle to long-term results of ultrasound-guided percutaneous longitudinal tenotomy of the Achilles tendon

METHOD

Seventy-five athletes with unilateral Achilles tendinopathy underwent ultrasound-guided percutaneous longitudinal tenotomy under local anesthetic infiltration after failure of conservative management. Sixty-three patients were reviewed at least 36 months after the operation (51 +/- 18.2 months).

RESULTS

Thirty-five patients were rated excellent, 12 good, 9 fair, and 7 poor. Nine of the 16 patients with a fair or poor result underwent a formal exploration of the Achilles tendon 7-12 months after the index procedure. The operated tendons remained thickened and the ultrasonographic appearance of operated tendons remained abnormal even 8 yr after the operation, without interfering with physical training. Isometric maximal muscle strength and isometric endurance gradually returned to values similar to their contralateral unoperated tendon.

CONCLUSIONS

Percutaneous longitudinal ultrasound-guided internal tenotomy is simple, can be performed on an outpatient basis, requires minimal follow-up care, does not hinder further surgery should it be unsuccessful, and, in our experience, has produced no significant complications. It should be considered in the management of chronic Achilles tendinopathy after failure of conservative management. However, patients should be advised that, if they suffer from diffuse or multinodular tendinopathy or from pantendinopathy, a formal surgical exploration with stripping of the paratenon and multiple longitudinal tenotomies may be preferable.

Tendon disorders attributed to fluoroquinolones: a study on 42 spontaneous reports in the period 1988 to 1998

OBJECTIVE

Fluoroquinolone antibiotics have been associated with tendinitis and tendon rupture. In this paper we report on the followup of 42 spontaneous reports of fluoroquinolone-associated tendon disorders.

METHODS

This study is based on cases of fluoroquinolone-associated tendon disorders reported to the Netherlands Pharmacovigilance Foundation Lareb and the Drug Safety Unit of the Inspectorate for Health Care between January 1, 1988, and January 1, 1998. By means of a mailed questionnaire, we collected information on the site of injury, onset of symptoms, treatment, and course of the tendon disorder as well as information on possible risk factors and concomitant medication.

RESULTS

Of 50 mailed questionnaires, 42 (84%) were returned. The data concerned 32 patients (76%) with tendinitis and 10 patients (24%) with a tendon rupture. Sixteen cases (38%) were attributed to ofloxacin, 13 (31%) to ciprofloxacin, 8 (19%) to norfloxacin, and 5 (12%) to pefloxacin. There was a male predominance, and the median age of the patients was 68 years. Most of the reports concerned the Achilles tendon, and 24 patients (57%) had bilateral tendinitis. The latency period between the start of treatment and the appearance of the first symptoms ranged from 1 to 510 days with a median of 6 days. Most patients recovered within 2 months after cessation of therapy, but 26% had not yet recovered at followup.

CONCLUSION

These reports suggest that fluoroquinolone-associated tendon disorders are more common in patients over 60 years of age. Ofloxacin was implicated most frequently relative to the number of filled prescriptions in the Netherlands.

Dynamised cast management of Achilles tendon ruptures

Non-operative treatment of closed ruptures of the Achilles tendon within 48 h of injury has been shown to produce results comparable with surgical treatment [1,2]. We report 49 patients treated using a dynamised cast, with a mean follow-up of 42 months, in which there has been only one case of re-rupture. A total of 33 patients were reviewed clinically and measurements revealed a mean calf circumference deficit of 1 cm and a mean functional range of ankle motion deficit of 3 degrees and plantar-flexion strength of 81-90%, when compared with the contra-lateral uninjured limb. Early mobilisation of the injured Achilles tendon using a dynamised cast has produced a re-rupture rate and functional recovery that compare favourably with previously published results for patients treated operatively. Non-operative management, in this way, is well tolerated by patients and is of low cost.

Biomechanical behavior of the plantar flexor muscle-tendon unit after an Achilles tendon rupture

The purpose of this study was to examine the biomechanical behavior of the plantar flexor muscle-tendon unit in subjects who had ruptured their Achilles tendon. Twenty-six men and 14 women volunteered for the study. Eighteen subjects had been treated operatively and 22, nonoperatively. All subjects had ruptured their Achilles tendon more than 1 year before the study, and 28 of the 40 ruptures occurred 5 years or less before the day of testing. A KinCom dynamometer was used to measure ankle joint angle, passive torque, and maximal isometric plantar flexor torque. During a 2-minute passive calf stretch, stiffness and torque relaxation were calculated. Isometric torque and peak passive torque were 17% and 10% greater for the uninvolved versus the involved limb, whereas stiffness and torque relaxation were not different between limbs. The time since injury did not influence the results, nor did the mode of initial treatment, that is, whether the subjects were treated operatively or nonoperatively. These findings suggest that changes in strength and peak passive torque may be chronic adaptations associated with Achilles tendon rupture.

Current concepts in imaging of tendinopathy

With the rising popularity of recreational sports, radiologists are being asked to image tendons with increasing frequency. Recognition of the critical link tendons provide between muscle and bone has also led to a better understanding of the processes leading to tendon damage. While plain radiography and CT have only a limited role to play in the diagnosis of tendon abnormality, the improvements in ultrasound and MRI technology mean that tendons can now be demonstrated in exquisite detail and previously undetectable abnormalities are readily demonstrated. This article reviews the structure and pathological processes affecting tendons and discusses the role of imaging in their assessment with an emphasis on ultrasound and MRI.

Light microscopic histology of achilles tendon ruptures. A comparison with unruptured tendons

We studied biopsies from the Achilles tendons of patients undergoing open repair for a subcutaneous rupture of their Achilles tendons (27 men, 11 women; mean age, 45.3 +/- 13.8 years) and specimens of Achilles tendons from persons with no known tendon ailments (43 men, 3 women; mean age, 64.2 +/- 9.7 years). Histologic examination was performed using stained slides that were interpreted using a semiquantitative grading scale assessing fiber structure and arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, hyalinization, and glycosaminoglycan. We gave up to three marks for each of these variables, with 0 being normal and 3 being maximally abnormal. All the histology slides were assessed twice in a blinded manner; the agreement between two readings ranged from 0.56 to 0.87 (kappa statistics). The score of ruptured tendons was significantly greater than the average score of control tendons (20.5 +/- 3.6 versus 6.5 +/- 2.1), and there was significantly higher degeneration in the ruptured tendons. Nonruptured Achilles tendons, even at an advanced age, and ruptured Achilles tendons are clearly part of two distinct populations. Using these staining techniques, light microscopic degeneration is not a feature of tendons from healthy, older persons.

Tenocytes from ruptured and tendinopathic achilles tendons produce greater quantities of type III collagen than tenocytes from normal achilles tendons. An in vitro model of human tendon healing

Type I collagen is the main collagen in tendons; type III collagen is present in small amounts. Ruptured Achilles tendons contain a significantly greater proportion of type Ill collagen, which predisposes them to rupture. We used an in vitro model to determine whether tenocytes from Achilles tendons that were ruptured (N = 22), nonruptured (N = 7), tendinopathic (N = 12), and fetal (N = 8) show different behavior. Samples of Achilles tendon were digested with collagenase and the released tenocytes were collected. Primary tenocyte cultures were established and subsequently cultured onto glass coverslips. Once a confluent monolayer was obtained, the cell populations were "wounded" by scraping a pipette tip along the surface. The cultures were further incubated for either 1, 4, 8, 12, 16, or 24 hours, and production of types I and II collagen was assessed by immunostaining. In cultures from ruptured and tendinopathic tendons, there was increased production of type Ill collagen. Athletic participation places excess stress on the Achilles tendon, which could potentially lead to areas of microtrauma within the tendon. These areas may heal by the production of type III collagen, which is an abnormal healing response. Accumulation of such episodes of microtrauma could resuit in a critical point where the resistance of the tissue to tensile forces is compromised and tendon rupture occurs.