The COL5A1 genotype is associated with range of motion measurements

There is an interest in identifying the intrinsic risk factors, including altered musculotendinous flexibility, that may be associated with musculotendinous injuries. We have recently shown that a sequence variant, namely the BstUI restriction fragment length polymorphism (RFLP), within the COL5A1 gene is associated with chronic Achilles tendinopathy. Mutations within COL5A1 have been implicated in Ehlers Danlos syndrome, a condition that is characterized by joint hypermobility. The aim of this study was to investigate the association of sequence variants within COL5A1 and musculotendinous range of motion (ROM). The sit and reach (SR) and the passive straight leg raise (SLR) were measured on 119 Caucasian subjects with either a past, current or no history of Achilles tendon injuries. The subjects were genotyped for four sequence variants within the 3′‐UTR of the COL5A1 gene. Gender (P=0.016), age (P=0.011) and the BstUI RFLP (P=0.010) jointly contributed significantly to the optimal SLR model which accounted for 19.3% of the variance. The factors contributing significantly to SR, which accounted for 28.8% of the variance, were weight (P=0.004), age (P<0.001) and the BstUI RFLP (P=0.001). These data suggest that the COL5A1 BstUI RFLP is independently associated with lower limb ROM within the cohort investigated in this study.     

The COL12A1 and COL14A1 genes and Achilles tendon injuries

Genes encoding for tenascin C and a subunit of type V collagen have previously been reported to be associated with Achilles tendon injuries. Types XII and XIV collagen may be involved in similar biological processes as these proteins in tendons. The aim of this study was therefore to test the association between polymorphisms within COL12A1 and COL14A1 and Achilles tendon injuries. Restriction fragment length polymorphism (RFLP) analysis was used to identify the relative frequencies of two polymorphisms within each of the COL12A1 and COL14A1 genes within 137 subjects with clinical symptoms of Achilles tendon injuries, consisting of 93 with Achilles tendinopathy and 44 with Achilles tendon rupture, and 131 asymptomatic control subjects. No statistically significant differences were identified in the genotype, allele or haplotype distributions between the affected and control subjects. The findings from this study suggest that although COL12A1 and COL14A1 are involved in similar biological processes as TNC and COL5A1, the polymorphisms tested are not associated with clinical symptoms of Achilles tendon injury within the investigated population.     

Range of motion measurements diverge with increasing age for COL5A1 genotypes

Increased and decreased joint range of motion (ROM) are modifiable risk factors for musculoskeletal soft-tissue injuries. Certain heritable disorders of connective tissue, which have a unifying symptom of joint hypermobility, are caused by mutations within the COL5A1 gene. Furthermore, the COL5A1 BstUI restriction fragment length polymorphism (RFLP) sequence variant is associated with ROM measurements in a mixed injured/uninjured cohort. The association between COL5A1 BstUI RFLP and sit and reach (SR) ROM in an apparently healthy and physically active cohort was investigated. The SR test was performed on 325 white subjects (204 males). Subjects were also genotyped for the BstUI RFLP (C/T) within the 3'-untranslated region of the COL5A1 gene. The COL5A1 BstUI RFLP genotype was associated with SR ROM in older (≥35 years) subjects (TT: 225 ± 96 mm, TC: 245 ± 100 mm, CC: 32 ± 108 mm, N=96, P=0.017). Age and COL5A1 BstUI genotype interacted significantly for SR ROM. Sex and COL5A1 genotype accounted for 22.8% of the variance in SR ROM in the older group. The COL5A1 BstUI RFLP is associated with SR ROM, particularly with increasing age and is an important contributing factor to ROM variation, particularly in older, apparently healthy and physically active individuals.     

The twisted structure of the human Achilles tendon

The Achilles tendon (AT) consists of fascicles that originate from the medial head of the gastrocnemius (MG), lateral head of the gastrocnemius (LG), and soleus muscle (Sol). These fascicles are reported to have a twisted structure. However, there is no consensus as to the degree of torsion. The purpose of this study was to investigate the twisted structure of the AT at the level of fascicles that originate from the MG, LG, and Sol, and elucidate the morphological characteristics. Gross anatomical study of 60 Japanese cadavers (111 legs) was used. The AT fascicles originated from the MG, LG, and Sol were fused while twisting among themselves. There were three classification types depending on the degree of torsion. Further fine separation of each fascicle revealed MG ran fairly parallel in all types, whereas LG and Sol, particularly of the extreme type, were inserted onto the calcaneal tuberosity with strong torsion. In addition, the sites of Sol torsion were 3–5 cm proximal to the calcaneal insertion of the AT. These findings provide promising basic data to elucidate the functional role of the twisted structure and mechanisms for the occurrence of AT injury and other conditions.     

Apolipoprotein A1 distribution pattern in the human Achilles tendon

Metabolic factors such as cholesterol appear to play an important role in the development of Achilles tendinopathy. There is, however, no morphologic proof explaining the link between high cholesterol and tendinopathy. As apolipoprotein A1 (Apo‐A1) is essential for reverse cholesterol transport, it may be related to cholesterol overload in tendon. Nothing is known about Apo‐A1 expression in tendon tissue. We examined the distribution of Apo‐A1 protein in biopsies from normal and tendinopathy‐affected human Achilles tendons, and APOA1 mRNA production from cultured human hamstring tenocytes. Specific immunoreactions for Apo‐A1 were detected. The tenocytes showed specific Apo‐A1 immunoreactions. These reactions were usually distinct in the tendinopathy specimens. While the tendinopathy specimens often showed granular/small deposit reactions, the slender tenocytes of control specimens did not show this pattern. The magnitude of Apo‐A1 immunoreactivity was especially marked in the tendinopathy specimens, as there is a high number of tenocytes. Reactions were also seen in the walls of blood vessels located within the tendon tissue proper of both the normal and tendinopathy tendons and within the peritendinous/fatty tissue of the tendinopathy tendons. The reactions were predominantly in the form of deposit reactions within the smooth muscle layer of the vessel walls. Cultured hamstring tenocytes produced APOA1 mRNA. We demonstrated the presence of Apo‐A1 in human tendon tissue. This suggests there may be a link between Achilles tendinopathy and cholesterol metabolism. We hypothesize that Apo‐A1 may be important for tenocyte and blood vessel function within tendons.     

Achilles tendon shape and echogenicity on ultrasound among active badminton players

The relationship between Achilles tendon ultrasound abnormalities, including a spindle shape and heterogeneous echogenicity, is unclear. This study investigated the relationship between these abnormalities, tendon thickness, Doppler flow and pain. Sixty‐one badminton players (122 tendons, 36 men, and 25 women) were recruited. Achilles tendon thickness, shape (spindle, parallel), echogenicity (heterogeneous, homogeneous) and Doppler flow (present or absent) were measured bilaterally with ultrasound. Achilles tendon pain (during or after activity over the last week) and pain and function [Victorian Institute of Sport Achilles Assessment (VISA‐A)] were measured. Sixty‐eight (56%) tendons were parallel with homogeneous echogenicity (normal), 22 (18%) were spindle shaped with homogeneous echogenicity, 16 (13%) were parallel with heterogeneous echogenicity and 16 (13%) were spindle shaped with heterogeneous echogenicity. Spindle shape was associated with self‐reported pain (P<0.05). Heterogeneous echogenicity was associated with lower VISA‐A scores than normal tendon (P<0.05). There was an ordinal relationship between normal tendon, parallel and heterogeneous and spindle shaped and heterogeneous tendons with regard to increasing thickness and likelihood of Doppler flow. Heterogeneous echogenicity with a parallel shape may be a physiological phase and may develop into heterogeneous echogenicity with a spindle shape that is more likely to be pathological.     

A new finding in the radiographic diagnosis of Achilles tendon rupture

The authors describe a new radiographic sign of rupture of the Achilles tendon system. It is a fracture, with separation through an osteophyte at the insertion of this tendon. Previously reported signs are also discussed as well as the present case report.     

Tendon elongation and muscle function after repair of Achilles tendon rupture

Thirty-four recreational atlethes with a mean age of 40 years were operated for a fresh subcutaneous rupture of the Achilles tendon with an approximating suture of the tendon in combination with 8 weeks in an equinus below-knee plaster. The elongation of the tendon during the rehabilitation was measured radiographically with implanted steel-wire indicators. The residual muscle function and the range of motion were recorded 1 year after the operation in 30 of the patients. There was no change in the passive range of motion and no elongation of the tendon during the primary healing period. The muscle function, measured with a special dynamic step test, was significantly impaired compared with the healthy side. Although the function was reduced in 17% of the patients, there was no subjective discomfort.     

A new surgical method to treat chronic ruptures and reruptures of the Achilles tendon

In patients with a chronic rupture or rerupture of the Achilles tendon, the recommended treatment is surgical. Various surgical techniques have been reported in the literature; however, the outcome is rarely evaluated with a sufficiently long follow-up, using appropriate end-points. The purpose of this study was to evaluate the subjective and objective outcome following a new surgical treatment for chronic rupture or rerupture of the Achilles tendon using augmentation with a free gastrocnemius aponeurosis flap. A total of 28 consecutive patients (22 male and 6 female) with a mean (SD) age of 46 (10.4) years were evaluated at a median (range) of 29 (12-117) months after surgery. The surgical technique involved making a single incision and then using a free gastrocnemius aponeurosis flap to cover the tendon gap after an end-to-end suture. The patients were evaluated using the Achilles tendon rupture score (ATRS) and a detailed questionnaire relating to symptoms, physical activity and satisfaction with treatment. The functional evaluation consisted of a validated test battery measuring different aspects of muscle/tendon function of the gastrocnemius/soleus and Achilles tendon complex. The median (range) ATRS was 83 (24-100). There were no reruptures. In terms of surgical complications, there was one deep infection, three wound closure complications and deep venous thrombosis in two patients. All but one patient returned to work within 6 months of surgery. Sixteen (57%) patients were satisfied with the treatment. There was a significant decrease in the level of physical activity after the injury compared with before the injury (p = 0.004). Of the 25 patients who participated in recreational sports prior to injury, 13 (52%) returned to the same activity level after treatment. In terms of jump performance, no significant differences were found between the healthy and injured sides. There was, however, a significant decrease in strength, in terms of both concentric and eccentric-concentric toe raises and the toe-raise test for endurance compared with the healthy side. The use of a free gastrocnemius aponeurosis flap to treat chronic ruptures and reruptures of the Achilles tendon rendered a good overall subjective and objective outcome in the majority of patients. The use of a single incision in combination with a free flap augmentation produced favourable results.     

The effects of immobilization on the quality of Achilles tendon in rats

Immobilization of an Achilles tendon in a shortened position for 1 and 3 weeks did not change pyridinoline and mature collagen concentrations. Although a significant decrease in the biosynthesis of collagen was observed simultaneously in the soleus muscle of the same hindlimb, these results suggest that the stability of collagen provided by the nonreducible cross-link, pyridinoline, is not altered during this type of immobilization. The significance of stable cross-links for the known decrease in tensile strength during immobilization remains open.     

Achilles tendon rupture – treatment and complications: A systematic review

Achilles tendon rupture is a frequent injury with an increasing incidence. Until now, there is no consensus regarding optimal treatment. The aim of this review was to illuminate and summarize randomized controlled trials comparing surgical and non‐surgical treatment of Achilles tendon ruptures during the last 10 years. Seven articles were found and they were all acceptable according to international quality assessment guidelines. Primary outcomes were re‐ruptures, other complications, and functional outcomes. There was no significant difference in re‐ruptures between the two treatments, but a tendency to favoring surgical treatment. Further, one study found an increased risk of soft‐tissue‐related complications after surgery. Patient satisfaction and time to return to work were significantly different in favor of surgery in one study, and there was also better functional outcome after surgery in some studies. These seven studies indicate that surgical patients have a faster rehabilitation. However, the differences between surgical and non‐surgical treatment appear to be subtle and it could mean that rehabilitation is more important, rather than the actual initial treatment. Therefore, further studies will be needed in regard to understanding the interplay between acute surgical or non‐surgical treatment, and the rehabilitation regimen for the overall outcome after Achilles tendon ruptures.     

Bilateral consecutive rupture of the quadriceps tendon in a man with BstUI polymorphism of the COL5A1 gene

A genetic component has been implicated in tendinopathies involving tendon rupture. Type V collagen, a quantitatively minor fibrillar collagen which forms heterotypic fibrils with type I collagen, plays a role in the regulation of the size and configuration of fibrils of the much more abundant component type I collagen. To date, no data on the genetic component of bilateral rupture of the quadriceps tendon have been reported. We describe the presence of BstUI polymorphism of the COL5A1 gene in a man with bilateral rupture of the quadriceps tendon. The COL5A1 (the variant rs12722, BstUI RFLP) can be a candidate gene associated with the development of bilateral quadriceps tendon rupture.