The Achilles tendon insertion is crescent-shaped: an in vitro anatomic investigation

Evaluation of 3D Footprint Morphology of Knee-Related Muscle Attachments Based on CT Data Reconstruction: A Feasibility Study

A three-dimensional (3D) understanding of muscle attachment footprints became increasingly relevant for musculoskeletal modeling. The established method to project attachments as points ignores patient-specific individuality. Research focuses on investigating certain muscle groups rather than comprehensively studying all muscles spanning a joint. Therefore, we present a reliable method to study several muscle attachments in order to reconstruct the attachment sites in 3D based on CT imaging for future applications in musculoskeletal modeling. For the present feasibility study, 23 knee-related muscle attachments were CT-scanned postmortem from four nonadipose male specimens. For this, the specific muscle attachments were dissected and marked with a barium sulfate containing paint (60 g BaSO4 in 30 mL water and 10 mL acrylic paint). Subsequently, bone geometries and muscle attachments were reconstructed and evaluated from CT datasets. Bone morphology and footprint variations were studied. Exemplarily, variations were high for pes anserinus insertions (mean 56%) and the origins of M. biceps femoris (mean 54%). In contrast, the origins of the vastus muscles as well as the insertion of the Achilles tendon showed low variation (mean 9% and 13%, respectively). Most attachment sites showed variation exceeding the individuality of bone morphology. In summary, the present data were consistent with the few published studies of specific muscle footprints. Our data shed light on the high variability of muscle attachments, which need to be addressed when studying muscle forces and movements through musculoskeletal modeling. This is the first step to achieving a more profound understanding of muscle morphology to be utilized in numerical simulations.

Current concept review of Achilles tendinopathy

Achilles tendinopathy is a common overuse injury affecting the ankle and foot. It manifests as a clinical condition that includes pain, edema, and decreased functionality. This condition can be broadly categorized into two main types based on anatomical location: insertional and noninsertional tendinopathy. The development of Achilles tendinopathy involves various factors, both internal and external. Patients with Achilles tendinopathy often experience stiffness worsened by prolonged rest, and pain exacerbated by physical activity. These symptoms can limit work activity and sports participation, with many patients facing discomfort while wearing shoes due to heel sensitivity. Diagnosis is primarily clinical, although MRI and ultrasound imaging can aid in differential diagnosis. Identifying risk factors and understanding the patient's biomechanics assist in accurate diagnosis and subsequent management. Management of Achilles tendinopathy involves a range of conservative and surgical options. However, due to varying results in clinical studies, a definitive gold standard treatment has not emerged. Eccentric exercises are a valuable tool in managing the condition. The recommend treatments such as shock wave therapy or nitric oxide patches are sought if symptoms do not improve. Peritendinous injections could be options if physical therapy proves ineffective. Surgical intervention is required after six months of conservative treatment. Recent research on Achilles tendinopathy emphasizes the need for individualized treatment plans that address its multifaceted nature. Combining biomechanical analysis, advanced imaging, and patient-specific factors is key to achieving optimal outcomes. Additionally, preventive strategies focusing on proper training techniques, load management, and addressing modifiable risk factors play a critical role in reducing the incidence of this condition. In conclusion, this article provides a current overview of Achilles tendinopathy. It highlights the importance of a comprehensive approach to understanding its causes, pathophysiology, diagnosis, and management strategies.

Growth factors in the treatment of Achilles tendon injury

Achilles tendon (AT) injury is one of the most common tendon injuries, especially in athletes, the elderly, and working-age people. In AT injury, the biomechanical properties of the tendon are severely affected, leading to abnormal function. In recent years, many efforts have been underway to develop effective treatments for AT injuries to enable patients to return to sports faster. For instance, several new techniques for tissue-engineered biological augmentation for tendon healing, growth factors (GFs), gene therapy, and mesenchymal stem cells were introduced. Increasing evidence has suggested that GFs can reduce inflammation, promote extracellular matrix production, and accelerate AT repair. In this review, we highlighted some recent investigations regarding the role of GFs, such as transforming GF-β(TGF-β), bone morphogenetic proteins (BMP), fibroblast GF (FGF), vascular endothelial GF (VEGF), platelet-derived GF (PDGF), and insulin-like GF (IGF), in tendon healing. In addition, we summarized the clinical trials and animal experiments on the efficacy of GFs in AT repair. We also highlighted the advantages and disadvantages of the different isoforms of TGF-β and BMPs, including GFs combined with stem cells, scaffolds, or other GFs. The strategies discussed in this review are currently in the early stages of development. It is noteworthy that although these emerging technologies may potentially develop into substantial clinical treatment options for AT injury, definitive conclusions on the use of these techniques for routine management of tendon ailments could not be drawn due to the lack of data.

Morphological variations of the calcaneal tendon: clinical significance

The calcaneal tendon, the largest and strongest in the human body, is created by the common junction of tendons of the gastrocnemius and soleus muscles. It is not a homogenous structure, being represented by layers in various arrangements. Morphological variability can be seen in the connection between the aponeurosis of the gastrocnemius muscle and the soleus muscle. Some types of plantaris tendon can be associated with a higher possibility of Achilles tendinopathy. Moreover, the presence of accessory structures, such as an accessory soleus muscle or additional gastrocnemius muscle heads may result in symptomatic pathologies. The main aim of this review is to summarize the current state of knowledge regarding the calcaneal tendon. Another aim is to present morphological variations of the calcaneal tendon and their clinical significance. Such information may be useful for clinicians, especially orthopedists, and surgeons. This review also provides an overview of embryological development and morphological variation among fetuses. Materials and methods: review was conducted according to PRISMA guidelines. An electronic search was conducted in five databases. Top quality tools were used to assess the quality of evidence in the studies reviewed. Research papers that made up the database of this review were analyzed, selected and assessed by two independently working researchers.

Quantifying the ossification and fusion of the calcaneal apophysis using computed tomography

Knowledge of the anatomical development of the calcaneal apophysis is essential in clinical assessment and management of both paediatric and sub‐adult patients presenting with heel pain. Despite this, the current understanding of calcaneal apophyseal development is constrained by the limitations of the imaging modalities used to examine the apophysis, with no current literature reporting the development of the medial and lateral processes. This study aimed to overcome these limitations by investigating the ossification and fusion of the calcaneal apophysis using three‐dimensional computed tomography analysis, and statistically predicting the apophyseal developmental stage in contemporary Australian children. The development and fusion status of the apophysis was scored using a novel 11‐stage scoring system on 568 multi‐slice computed tomography scans (295 females; 274 males) and 266 lateral radiographic scans (119 females; 147 males) from the Queensland Children's Hospital. Multinomial logistic regression along with classification tables and predictive probabilities were then utilised to assess developmental stage likelihood from known age and sex. The apophysis commenced ossification at a mean age of 5.2 years for females and 7.2 years for males, and then elongated to form the apophyseal cap around 10 years for females and 12.4 years for males. Fusion of the apophysis commenced at a mean age of 11.18 years for females and 13.3 years for males, with the earliest age of complete fusion observed at 10 years for females and 14 years for males. The results demonstrate significant sexual dimorphism in ossification and fusion with females developing and fusing significantly earlier. Furthermore, the use of computed tomography in this study allowed for the first time evaluation of the ossification and fusion of the medial and lateral processes of the calcaneus. The medial process formed at a mean age of 9.5 years for females and 10.9 years for males while the lateral process formed at around 9.8 years for females and 11.7 years for males. The medial process demonstrated slower rates of fusion compared to the lateral process. The present study provides Queensland specific standards for assessing the calcaneal apophyseal developmental stage as well as novel predictive regression models for apophyseal stage estimation using known age and sex to aid in the diagnosis of heel pain conditions such as apophysitis or screen for developmental delays in children and subadults.

Treatment of Acute Achilles Tendon Rupture

There is no clear consensus on the optimal treatment of acute Achilles tendon rupture. Recently, studies have demonstrated the critical role of functional rehabilitation in the treatment of ruptured Achilles tendons. Hence, conservative treatment is preferred by a growing number of surgeons seeking to treat the condition without the risk of complications from surgery. However, operative treatment is still considered as a more reliable treatment option for acute Achilles tendon rupture. In this review article, we provide an overview of recent treatment strategies for acute rupture of the Achilles tendon.

Ankle Joint Position and the Reliability of Ultrasound Tissue Characterization of the Achilles Tendon: A Pilot Study

Background

Imaging of the Achilles tendon using ultrasound tissue characterization (UTC) involves taking up the slack of the tendon by including dorsiflexion of the ankle. This pilot study aimed to determine whether different longitudinal tension applied to the Achilles tendon during imaging affected the reliability of UTC.

Material/Methods

Nine asymptomatic active volunteers, aged between 23–49 years underwent imaging of 17 Achilles tendons. Three positions of tension included plantar grade, 50%, and 100% of maximal dorsiflexion, with a range of 18–32°. Ranges were established and standardized using an isokinetic dynamometer. A test and re-test process was conducted at each position to determine the intraclass correlation coefficients (ICCs) and minimum detectable change (MDC) per echotype. Images were analyzed using UTC software.

Results

Plantar grade positioning images could not be obtained. ICCs for each echotype I–IV between test 1 and test 2 were 0.965, 0.962, 0.858, 0.739 at 100% dorsiflexion (95% CI, 0.86–0.99, 0.84–0.99, 0.51–0.97, and 0.2–0.94), and 0.771, 0.551, 0.569, 0.429 at 50% dorsiflexion (95% CI, 0.29–0.94, −0.09–0.88, −0.01–0.88, and −0.15–0.82). The MDC per echotype I–IV ranged between 4.1–1.0% of echotype data at 100% dorsiflexion, and 17.2–6.3% at 50% dorsiflexion.

Conclusions

Testing at maximum dorsiflexion provided improved reliability when using UTC in healthy individuals. The ICC at 100% dorsiflexion was increased, and the MDC was reduced for all echotypes. Therefore, standardizing test positions when using UTC is advisable for reliable comparison of results between studies.

Quantitative Magnetic Resonance Imaging Analysis of the Common Site of Acute Achilles Tendon Rupture: 5 to 8 cm Above the Distal End of the Calcaneal Insertion

BACKGROUND

Previous studies have not quantitatively analyzed the site of acute Achilles tendon rupture.

PURPOSE

To investigate the site of acute Achilles tendon rupture via magnetic resonance imaging (MRI).

STUDY DESIGN

Cross-sectional study; Level of evidence, 4.

METHODS

The medical records and MRIs of 195 patients with acute Achilles tendon rupture were retrospectively reviewed. The rupture site was measured as the distance from the most distal fibers of the Achilles tendon at the calcaneal insertion to the proximal end of the distal stump. The relationship between the site of rupture and patient characteristics was analyzed, and the intra- and interobserver reliability of the measurements was assessed using intraclass correlation coefficients.

RESULTS

The rupture site had a mean distance of 6.4 cm (SD, 1.5) and the 10th to 90th percentile range was 5.0 to 8.4 cm. There was no significant difference in location of the rupture according to patient characteristics and the time of imaging. The intra- and interobserver reliability of measurements was excellent.

CONCLUSION

Most acute Achilles tendon ruptures visible on MRI occurred 5 to 8 cm above the distal end of the calcaneal insertion, which is more proximal than the previously reported 2 to 6 cm location.

The Calcaneal Crescent in Patients With and Without Plantar Fasciitis: An Ankle MRI Study

OBJECTIVE

The bundled, crescent-shaped trabeculae within the calcaneal tuberosity-which we term and refer to here as the "calcaneal crescent"-may represent a structural adaption to the prevailing forces. Given Wolff law, we hypothesized that the calcaneal crescent would be more robust in patients with plantar fasciitis, a syndrome in part characterized by overload of the Achilles tendon-calcaneal crescent-plantar fascia system, than in patients without plantar fasciitis.

MATERIALS AND METHODS

MR images of 37 patients (27 women and 10 men; mean age ± SD, 51 ± 13 years; mean body mass index [BMI, weight in kilograms divided by the square of height in meters], 26.8 ± 6.3) referred for workup of foot or ankle pain were retrospectively evaluated by two blinded readers in this study. Patients were assigned to two groups: group A, which was composed of 15 subjects without clinical signs or MRI findings of Achilles tendon-calcaneal crescent-plantar fascia system abnormalities, or group B, which was composed of 22 patients with findings of plantar fasciitis. The thickness and cross-sectional area (CSA) of the Achilles tendon, calcaneal crescent, and plantar fascia were measured on proton density (PD)-weighted MR images. The entire crescent volume was manually measured using OsiriX software on consecutive sagittal PD-weighted images. Additionally, contrast-to-noise ratio (CNR) as a surrogate marker for trabecular density and the mean thickness of the calcaneal crescent were determined on PD-weighted MR images. The groupwise difference in the morphologic measurements were evaluated using ANOVA with BMI as a covariate. Partial correlation was used to assess the relationships of measurements for the group with plantar fasciitis (group B). Intraclass correlation coefficient (ICC) statistics were performed.

RESULTS

Patients with plantar fasciitis had a greater CSA and volume of the calcaneal crescent and had lower CNR (i.e., denser trabeculae) than those without Achilles tendon-calcaneal crescent-plantar fascia system abnormalities (CSA, 100.2 vs 73.7 mm², p = 0.019; volume, 3.06 vs 1.99 cm³, p = 0.006; CNR, -28.40 vs -38.10, p = 0.009). Interreader agreement was excellent (ICC = 0.85-0.99).

CONCLUSION

In patients with plantar fasciitis, the calcaneal crescent is enlarged compared with those without abnormalities of the Achilles tendon-calcaneal crescent-plantar fascia system. An enlarged and trabeculae-rich calcaneal crescent may potentially indicate that abnormally increased forces are being exerted onto the Achilles tendon-calcaneal crescent-plantar fascia system.

Endoscopic Achilles Tendon Augmentation With Suture Anchors After Calcaneal Exostectomy in Haglund Syndrome

BACKGROUND

Haglund syndrome is a common cause of heel pain. Risk for tendon detachment after calcaneoplasty can exist. Open Achilles tendon detachment, calcaneoplasty, bursectomy, pathologic tendon-tissue debridement, and tendon reattachment of the Achilles tendon is a common surgical management of Haglund syndrome combined with insertional Achilles tendinopathy. The aim of this study was to describe the endoscopic calcaneoplasty and anchor suture augmentation of the Achilles insertional area, and the results obtained in patients with an increased risk of Achilles tendon rupture after calcaneoplasty.

METHODS

Between 2012 and 2015, endoscopic calcaneal ostectomy and suture anchor augmentation was performed in 12 patients. Mean age was 44.8 years (range, 35-52 years), and mean follow-up was of 33.5 months (range, 21-46 months).

RESULTS

The mean AOFAS score increased from 70 preoperatively (range, 55-85) to 92 (range, 63-100) at final follow-up. The mean VISA-A questionnaire increased from 34 preoperatively (range, 15-63) to 92 (range, 30-100) at follow-up. No major complications were reported. All patients returned to their daily activities without limitations, but 2 described complaints with sports activity.

CONCLUSION

Endoscopic calcaneoplasty and tendon augmentation with suture anchor for the treatment of Haglund syndrome was a reproducible and safe technique that offered the advantages of the endoscopic technique.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

A Proposed Staging Classification for Minimally Invasive Management of Haglund's Syndrome with Percutaneous and Endoscopic Surgery

Haglund's syndrome encompasses several different pathologies, including Haglund's deformity, insertional Achilles tendonopathy, retrocalcaneal bursitis, and superficial bursitis. Traditionally treated with open surgery, there is increasing interest in a more minimally invasive approach to this difficult region to reduce complications and improve the rate and ease of recovery. We review the evidence available for 2 of these techniques: the endoscopic calcaneoplasty and percutaneous Zadek's calcaneal osteotomy (also known as Keck and Kelly's osteotomy). The senior author's classification for management of the condition is presented as well as describing his operative technique for these procedures.

Characterization and Surgical Management of Achilles Tendon Sleeve Avulsions

BACKGROUND

An Achilles sleeve avulsion occurs when the tendon ruptures distally from its calcaneal insertion as a continuous "sleeve." This relatively rare injury pattern may not be appreciated until the time of surgery and can be challenging to treat because, unlike a midsubstance rupture, insufficient tendon remains on the calcaneus to allow for end-to-end repair, and unlike a tuberosity avulsion fracture, any bony element avulsed with the tendon is inadequate for internal fixation. This study aimed to highlight the characteristics of Achilles sleeve avulsions and present the outcomes of operative repair using suture anchor fixation.

METHODS

A retrospective analysis was conducted on 11 consecutive Achilles tendon sleeve avulsions (10 males, 1 female; mean age 44 years) that underwent operative repair between 2008 and 2014. Patient demographics, injury presentation, and operative details were reviewed. Postoperative outcomes were collected at a mean follow-up of 38.4 (range, 12-83.5) months, including the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot score, visual analog scale (VAS) for pain, plantarflexion strength, patient satisfaction, and complications.

RESULTS

Eight patients (72.7%) had preexisting symptoms of insertional Achilles disease. Ten of 11 (90.9%) injuries were sustained during recreational athletic activity. An Achilles sleeve avulsion was recognized preoperatively in 7 of 11 (64%) cases, where lateral ankle radiographs demonstrated a small radiodensity several centimeters proximal to the calcaneal insertion. Intraoperatively, 90.9% of sleeve avulsions had a concomitant Haglund deformity and macroscopic evidence of insertional tendinopathy. All patients healed after suture anchor repair. The average AOFAS score was 92.8 and VAS score was 0.9. Ten patients (90.9%) were completely satisfied. One complication occurred, consisting of delayed wound healing.

CONCLUSIONS

Achilles tendon sleeve avulsions predominantly occurred in middle-aged men with preexisting insertional disease, while engaged in athletic activity. Suture anchor fixation, combined with addressing concomitant insertional pathology, was a reliable and safe technique for the operative management of Achilles tendon sleeve avulsions. The majority of patients returned to their preinjury levels of work and recreational activity.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Treatment of Calcified Insertional Achilles Tendinopathy by the Posterior Midline Approach

The present study investigated the clinical outcomes of the posterior midline approach in the treatment of 34 patients with significantly calcified insertional Achilles tendinopathy. The posterior midline approach was applied for the surgical treatment of 34 patients with chronic significantly calcified insertional Achilles tendinopathy after failed conservative treatment. Gastrocnemius recession was performed simultaneously for patients with gastrocnemius contracture. The Fowler-Philip angle and parallel pitch lines were measured before surgery, and the visual analog scale, Tegner score, and Victorian Institute of Sport tendon study group score were recorded before and after surgery. The mean follow-up period was 45.2 ± 17.7 (range 24 to 84) months. After surgery, the visual analog scale score had decreased notably, and the Tegner score and Victorian Institute of Sport tendon study group score had increased significantly. The posterior midline approach can achieve satisfactory outcomes in the treatment of significantly calcified insertional Achilles tendinopathy, and gastrocnemius recession (Strayer procedure) should be performed for patients with gastrocnemius contracture to improve the surgical outcome.

The anatomical footprint of the Achilles tendon

We dissected 12 fresh-frozen leg specimens to identify the insertional footprint of each fascicle of the Achilles tendon on the calcaneum in relation to their corresponding muscles. A further ten embalmed specimens were examined to confirm an observation on the retrocalcaneal bursa. The superficial part of the insertion of the Achilles tendon is represented by fascicles from the medial head of the gastrocnemius muscle, which is inserted over the entire width of the inferior facet of the calcaneal tuberosity. In three specimens this insertion was in continuity with the plantar fascia in the form of periosteum. The deep part of the insertion of the Achilles tendon is made of fascicles from the soleus tendon, which insert on the medial aspect of the middle facet of the calcaneal tuberosity, while the fascicles of the lateral head of the gastrocnemius tendon insert on the lateral aspect of the middle facet of the calcaneal tuberosity. A bicameral retrocalcaneal bursa was present in 15 of the 22 examined specimens.

This new observation and description of the insertional footprint of the Achilles tendon and the retrocalcaneal bursa may allow a better understanding of the function of each muscular part of the gastrosoleus complex. This may have clinical relevance in the treatment of Achilles tendinopathies.

Cite this article: Bone Joint J 2014; 96-B:1344–8

Results of operative treatment for recalcitrant retrocalcaneal bursitis and midportion Achilles tendinopathy in athletes

BACKGROUND

The results of operative treatment for recalcitrant midportion Achilles tendinopathy and recalcitrant retrocalcaneal bursitis were evaluated using the patient administered, disease specific, and validated VISA-A-G questionnaire.

METHODS

A cohort of 89 patients was prospectively followed. These patients underwent operations for sport induced midportion Achilles tendinopathy (39 procedures) or retrocalcaneal bursitis (55 procedures). Depending on the individual intraoperative findings the patients of either disease were treated with two respective operative modifications (tendon repair or no tendon repair). Preoperative and follow-up status (3, 6, and 12 months) were investigated using the VISA-A-G questionnaire.

RESULTS

Preoperatively, the four groups scored from 37.0 ± 17.6 to 45.9 ± 15.2 (p = 0.376-0.993) on the VISA-A-G questionnaire. Six and 12 months postoperatively, the VISA-A-G scores improved significantly (p < 0.001). Twelve months postoperatively, the groups' scores were not different (p = 0.100-0.952) and ranged from 80.8 ± 17.9 to 90.3 ± 10.6.

CONCLUSION

Retrocalcaneal bursitis and midportion Achilles tendinopathy responded equally well to operative treatment. When repaired, additional tendon lesions did not influence this result. We demand to differentiate not only between midportion Achilles tendinopathy and retrocalcaneal bursitis but also to identify additional Achilles tendon lesions to specifically address these lesions during operative procedures.

Retrocalcaneal bursitis but not Achilles tendinopathy is characterized by increased pressure in the retrocalcaneal bursa

BACKGROUND

We questioned whether different forms of Achilles tendon overuse injuries can be differentiated by retrocalcaneal bursa pressure measurement.

METHODS

Retrocalcaneal bursa pressure was determined by using invasive pressure measurement in patients suffering from retrocalcaneal bursitis (n=13) or Achilles tendinopathy (n=15), respectively. Standardized measurements were taken with the subject lying prone. Initially, the foot and ankle was in a spontaneous, unsupported position. Then passive dorsiflexion was induced by an increasing pressure which was applied in five defined steps against the plantar forefoot.

FINDINGS

Mean pressures found in unloaded position were 30.5 (SD 28.9) mmHg in retrocalcaneal bursitis and -9.9 (SD 17.2) mmHg in Achilles tendinopathy (p<0.001). A stepwise increase in passive ankle dorsiflexion was associated with increasing pressure values in both groups. The differences were p=0.009 to 0.035 when dorsiflexion was initiated with 10, 20, 30, and 40N, respectively. Dorsiflexion induced by 50N load resulted in a mean pressure of 113.7 (SD 124.9) mmHg for retrocalcaneal bursitis and 32.5 (SD 48.9) mmHg for Achilles tendinopathy (p=0,051).

INTERPRETATION

Higher retrocalcaneal bursa pressure values were found in patients suffering from chronic retrocalcaneal bursitis. This result supports the hypothesis that retrocalcaneal bursa hypertension leads to an impingement lesion of the corresponding anterior Achilles tendon.

Clinical anatomy of the ankle and foot

This paper emphasizes the anatomical substrate of several foot conditions that are seldom discussed in this context. These include the insertional and non-insertional Achilles tendinopathies, plantar fasciopathy, inferior and posterior heel spurs, foot compartment syndromes, intermetatarsal bursitis and Morton's neuroma. It is a rather superficial anatomical review of an organ that remains largely neglected by rheumatologists. It is our hope that the cases discussed and the cross examination by instructors and participants will stimulate study of the foot and the attention it deserves.

Minimally invasive retrocalcaneal bursa pressure measurement: development and pilot application

Up to now diagnosis of Haglund's disease is based on patient's history and clinical findings. There is no valid diagnostic tool described to functionally detect retrocalcaneal bursitis. Retrocalcaneal bursa pressure may be increased in these patients. We hypothesized that retrocalcaneal bursa pressure can directly be measured. In this pilot investigation we tested the feasibility of a system which is already in clinical use for arterial blood pressure monitoring to quantitatively assess retrocalcaneal bursa pressure in a human and a swine cadaver specimen and in vivo. Using the presented system retrocalcaneal bursa pressure measurement is demonstrated to be feasible. Moreover, intrabursal pressure is reproducibly and validly quantified. In an uninjured subject increasing ankle dorsiflexion was not associated with increasing pressure in the retrocalcaneal bursa. Experimental liquid injection in the retrocalcaneal bursa was associated with increased intrabursal pressure and increasing pain. Feasibility of the tested setup could be proven. The question, if retrocalcaneal bursitis can be distinguished from further heel pathologies by different pressures in the retrocalcaneal bursa has to be addressed in a subsequent in vivo study.

Variability of insertion of the Achilles tendon on the calcaneus: an MRI study of younger subjects

The insertional location of the Achilles tendon traditionally has been thought to be on the superior aspect of the calcaneus. This is based on descriptions and illustrations in anatomical textbooks. Our study is a digital magnetic resonance imaging (MRI) examination of the insertional location of the Achilles tendon in 69 subjects, 12 to 40 years of age. A midsagittal slice of the ankle was used to identify the most distal insertional location of the Achilles tendon on the posterior aspect of the calcaneus. The superior and inferior margins of the posterior aspect of the calcaneus were measured and the Achilles tendon insertion was calculated as a percentage of the total length of the posterior aspect of the calcaneus. Our results revealed that there is a statistically significant difference in the insertional location as related to age. Additionally, there is a statistically significant proximal migration (0.63%) of the insertional location with each advancing year. Based on our results, it appears that there is an inaccurate depiction in the anatomical literature, which may necessitate a change in the approach to pathologic conditions associated with the Achilles tendon.

Painful prominences of the heel

Heel pain is a common malady, with reported prevalence ranging from 4% to 21%. Referral to foot and ankle specialists for heel pain is also common, but patient awareness of the cause of heel pain may be limited. Many misconceptions about how heel exostoses relate to heel pain exist in the medical community and the general patient population, with many patients referred for or presenting with the simple complaint ''I have a heel spur.'' This article reviews the common exostoses of the heel, including plantar, lateral, and posterior spurs, with specific attention to the cause and treatments.

The variability of the Achilles tendon insertion: a cadaveric examination

Pathology associated with the Achilles tendon is a common problem, particularly at the site of insertion. A better understanding of the anatomy in this area would assist in developing and fine-tuning treatment options. A cadaveric examination was conducted using 60 human lower extremities (40 cadavers) to determine the location for the terminal insertion site of the Achilles tendon on the posterior aspect of the calcaneus. The average age of the specimens was 67.8 years (range, 43-98 years). Three different investigators examined each specimen, and a consensus as to the site of termination of the Achilles tendon was made. Upon inspection, 55% (22/40) of the limbs had the Achilles tendon inserting on the superior 1/3 aspect of the calcaneus, 40% (16/40) of the limbs inserted on the middle 1/3, and 5% (2/40) of the limbs inserted on the inferior 1/3. The distribution of the insertion was statistically different from random (P = .000371). Further, 8% (3/40) of the specimens revealed a partially contiguous relationship between the Achilles tendon and the plantar fascia. This correlated with the younger specimens (P < .0001). This study provides a better understanding of the anatomical relationship between the Achilles tendon, the calcaneus, and the plantar fascia.

Functional anatomy of the Achilles tendon

The Achilles tendon is the strongest and thickest tendon in the human body. It is also the commonest tendon to rupture. It begins near the middle of the calf and is the conjoint tendon of the gastrocnemius and soleus muscles. The relative contribution of the two muscles to the tendon varies. Spiralisation of the fibres of the tendon produces an area of concentrated stress and confers a mechanical advantage. The calcaneal insertion is specialised and designed to aid the dissipation of stress from the tendon to the calcaneum. The insertion is crescent shaped and has significant medial and lateral projections. The blood supply of the tendon is from the musculotendinous junction, vessels in surrounding connective tissue and the osteotendinous junction. The vascular territories can be classified simply in three, with the midsection supplied by the peroneal artery, and the proximal and distal sections supplied by the posterior tibial artery. This leaves a relatively hypovascular area in the mid-portion of the tendon where most problems occur. The Achilles tendon derives its innervation from the sural nerve with a smaller supply from the tibial nerve. Tenocytes produce type I collagen and form 90% of the cellular component of the normal tendon. Evidence suggests ruptured or pathological tendon produce more type III collagen, which may affect the tensile strength of the tendon. Direct measurements of forces reveal loading in the Achilles tendon as high as 9 KN during running, which is up to 12.5 times body weight.

Cross-cultural adaptation and validation of the VISA-A questionnaire for German-speaking achilles tendinopathy patients

BACKGROUND

Achilles tendinopathy is the predominant overuse injury in runners. To further investigate this overload injury in transverse and longitudinal studies a valid, responsive and reliable outcome measure is demanded. Most questionnaires have been developed for English-speaking populations. This is also true for the VISA-A score, so far representing the only valid, reliable, and disease specific questionnaire for Achilles tendinopathy. To internationally compare research results, to perform multinational studies or to exclude bias originating from subpopulations speaking different languages within one country an equivalent instrument is demanded in different languages. The aim of this study was therefore to cross-cultural adapt and validate the VISA-A questionnaire for German-speaking Achilles tendinopathy patients.

METHODS

According to the "guidelines for the process of cross-cultural adaptation of self-report measures" the VISA-A score was cross-culturally adapted into German (VISA-A-G) using six steps: Translation, synthesis, back translation, expert committee review, pretesting (n = 77), and appraisal of the adaptation process by an advisory committee determining the adequacy of the cross-cultural adaptation. The resulting VISA-A-G was then subjected to an analysis of reliability, validity, and internal consistency in 30 Achilles tendinopathy patients and 79 asymptomatic people. Concurrent validity was tested against a generic tendon grading system (Percy and Conochie) and against a classification system for the effect of pain on athletic performance (Curwin and Stanish).

RESULTS

The "advisory committee" determined the VISA-A-G questionnaire as been translated "acceptable". The VISA-A-G questionnaire showed moderate to excellent test-retest reliability (ICC = 0.60 to 0.97). Concurrent validity showed good coherence when correlated with the grading system of Curwin and Stanish (rho = -0.95) and for the Percy and Conochie grade of severity (rho 0.95). Internal consistency (Cronbach's alpha) for the total VISA-A-G scores of the patients was calculated to be 0.737.

CONCLUSION

The VISA-A questionnaire was successfully cross-cultural adapted and validated for use in German speaking populations. The psychometric properties of the VISA-A-G questionnaire are similar to those of the original English version. It therefore can be recommended as a sufficiently robust tool for future measuring clinical severity of Achilles tendinopathy in German speaking patients.