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PubMed2006

[Clinical application of peroneal muscles tendon transposition in repair of Achilles tendon rupture].

OBJECTIVE: To discuss applied anatomy, biomechanics and surgical procedures of long peroneal muscles tendon transposition in repair of occlusive achilles tendon rupture. METHODS: The blood supply and the morphology of long peroneal muscles tendon were observed in the lower extremity of 50 sides adult specimens and the mechanical tests which stretch load on the tendon were carried out. The methods were designed on the basis of the anatomical characteristics and morphology. Ten patients suffering occlusive Achilles tendon rupture were treated by using long peroneal muscles tendon transposition from March 2001 to July 2004. Among 10 patients, there were 7 males and 3 females, aging 32 to 54 years including 6 cases of jump injury, 2 cases of bruise, 1 case of step vacancy and 1 case of spontaneity injury. The interval between injury and surgery was 6 hours to 7 days in 7 fresh rupture and 21 days to 3 months in 3 old rupture. All cases belonged to occlusive Achilles tendon rupture (8 cases of complete rupture and 2 cases of incomplete rupture). RESULTS: The origin of long peroneal muscles was proximal tibia and fibular head, the end of them was base of first metatarsal bones and medial cuboid. The length of tendon was 13.5 +/- 2.5 cm. The width of origin tendon was 0.9 +/- 0.2 cm and the thickness was 0.3 +/- 0.1 cm; the width on apex of lateral malleolus was 0.7 +/- 0.1 cm and the thickness was 0.4 +/- 0.1 cm, the width on head of cuboid was 0.7 +/- 0.1 cm and the thickness was 0.3 +/- 0.1 cm. The long peroneal muscles tendon had abundant blood supply. The results of mechanical test showed that the biggest load was 2,292.4 +/- 617.3 N on tendon calcaneus, 1,020.4 +/- 175.4 N on long peroneal muscles tendon, 752.0 +/- 165.4 N on peroneus brevis tendon and 938.2 +/- 216.7 N on tibialis posterior tendon. Ten cases of occlusive Achilles tendon rupture achieved healing by first intention and were followed up 18-24 months. No Achilles tendon re-rupture, necrosis of skin or other complications occurred. According to Amerind-holm criterion for curative results, the results were excellent in 7 cases and good in 3 cases and the excellent and good rate was 100%. CONCLUSION: The long peroneal muscles tendon transposition is a perfect and simple way to repair occlusive Achilles tendon rupture.

Achilles Tendon↗
PubMed2002

A comparative study of bone to bone repair and bone to tendon healing in patella-patellar tendon complex in rabbits.

OBJECTIVES: To study the healing quality of bone to bone and bone to tendon repair in a patella-patellar tendon complex. DESIGN: In vivo animal experiment in 60 mature 32-week-old female rabbits. BACKGROUND: Injuries of patella-patellar tendon complex are not uncommon. However, no studies are available to compare the healing quality between bone to bone and bone to tendon surgical reconstructions used for repair of patella-patellar tendon complex. METHODS: A standard transverse osteotomy was performed at the distal one-third of patella of one hindlimb. Both patellar fragments were reattached for bone to bone group while the patellar tendon was reattached to the remaining patella after removing the distal one-third of patella for bone to tendon group. Patella-patellar tendon complex was harvested at 8, 12 and 24 weeks postoperatively for biomechanical and histological evaluations, with n=8 and n=2 at each healing time points in both groups. The contralateral knee served as a control. RESULTS: No significant differences in the failure loads were found between two groups. However, greater ultimate stress was found in bone to bone group as compared with bone to tendon group at week 8 and 24 (both P<0.05). On average, the ultimate stress of the bone to tendon and bone to bone group only reached 20.6(4.2)% and 28.6(6.7)% of the control values at week 24, respectively. The discrepancy between findings in failure load and failure stress might be explained by an overall larger cross-sectional area of the healing interface in bone to tendon group as compared with bone to bone group. Histology revealed that the bone to bone healing was via endochondral ossification at the healing interface. In bone to tendon group, extensive scar tissue was formed to overbridge the healing interface and remodeled with healing over time. The structural integration at the tendon and bony healing interface was poor and no typical intermitted fibrocartilage zone as seen in normal bone to tendon junction was formed. CONCLUSION: Failure load of bone to bone and bone to tendon healing interface did not differ during repair of patella-patellar tendon complex. However, the healing interface of bone to bone repair in terms of material properties as reflected by failure stress was superior to that of the bone to tendon healing. RELEVANCE: The findings of this experimental study may suggest that the anatomical reconstruction of patella-patellar tendon complex injury may be the primary concern in decision making for selecting either bone to bone or bone to tendon repair. However whenever possible, to initial fracture (bone-to-bone) fixation for ensuring better and predictable repair at the healing interface.

Analysis of Variance↗
PubMed1994

Tendon degeneration and chronic shoulder pain: changes in the collagen composition of the human rotator cuff tendons in rotator cuff tendinitis.

OBJECTIVES: To analyse the collagen composition of normal adult human supraspinatus tendon and to compare with: (1) a flexor tendon (the common biceps tendon) which is rarely involved in any degenerative pathology; (2) degenerate tendons from patients with chronic rotator cuff tendinitis. METHODS: Total collagen content, collagen solubility and collagen type were investigated by hydroxyproline analysis, acetic acid and pepsin digestion, cyanogen bromide peptide analysis, SDS-PAGE and Western blotting. RESULTS: The collagen content of the normal cadaver supraspinatus tendons (n = 60) was 96.3 micrograms HYPRO/mg dry weight (range 79.3-113.3) and there was no significant change across the age range 11 to 95 years. There was no significant difference from the common biceps tendon [93.3 (13.5) micrograms HYPRO/mg dry weight, n = 24]. Although extremely insoluble in both acetic acid and pepsin, much of the collagen was soluble after cyanogen bromide digestion [mean 47.9% (29.8)]. Seventeen per cent (10/60) of the 'normal' cadaver supraspinatus tendon sample contained more than 5% type III collagen, although none of the common biceps tendons had significant amounts. Degenerate supraspinatus and subscapularis tendons had a reduced collagen content [83.8 (13.9) micrograms/mg dry weight and 76.9 (16.8) micrograms/mg dry wt respectively) and were more soluble in acetic acid, pepsin and cyanogen bromide (p < 0.001). Eighty two per cent (14/17) of supraspinatus tendons and 100% (8/8) of subscapularis tendons from patients with tendinitis contained more than 5% type III collagen. CONCLUSIONS: The changes in collagen composition in rotator cuff tendinitis are consistent with new matrix synthesis, tissue remodelling and wound healing, in an attempt to repair the tendon defect, even in old and degenerate tendons. An increase in type III collagen in some 'normal' cadaver supraspinatus tendons is evidence that changes in collagen synthesis and turnover may precede tendon rupture. These changes may be the result of repeated minor injury and microscopic fibre damage or a consequence of local factors such as reduced vascular perfusion, tissue hypoxia, altered mechanical forces and the influence of cytokines. These collagenous changes may accumulate with age and substantially weaken the tendon structure, predisposing the tendon to rotator cuff tendinitis and eventual tendon rupture.

Adolescent↗
PubMed2006

Residual strength of the quadriceps versus patellar tendon after harvesting a central free tendon graft.

PURPOSE: Free tendon grafts for reconstruction of the anterior cruciate ligament have become more prevalent with the desire for reduced morbidity, earlier postoperative rehabilitation, and improved free tendon graft fixation. The central quadriceps tendon autograft is an alternative to bone-patellar tendon-bone and free hamstring autografts. The purpose of this study was to measure the postharvest reduction in quadriceps extensor mechanism strength when a central quadriceps free tendon graft is removed. The strength deficit was compared with that associated with harvesting a central free patellar tendon graft, excluding the effects of harvesting bone blocks. TYPE OF STUDY: Experimental laboratory study. METHODS: Fourteen knee extensor mechanisms were divided into quadriceps and patellar tendon constructs. Constructs were tested to failure in tension in either the intact state or after removing 10-mm wide central free tendon grafts. Failure strengths of the quadriceps and patellar tendon constructs were compared statistically using paired and unpaired t tests. RESULTS: The average strength (+/-SD) measured for the native quadriceps tendon was 3,660 +/- 830 N, decreasing to 2,430 +/- 680 N after removing a partial-thickness 10-mm wide central free graft. The average strength measured for the native patellar tendon was 1,920 +/- 330 N, decreasing to 1,460 +/- 740 N after removing a 10-mm wide central free graft. CONCLUSIONS: The tensile strength of the quadriceps tendon is reduced by approximately one third after harvesting a partial-thickness 10-mm wide central free tendon graft. This postharvest strength of the quadriceps tendon is higher than that of the intact patellar tendon. CLINICAL RELEVANCE: Surgeons can be assured that harvest of a central quadriceps free tendon graft leaves a stronger extensor mechanism than harvest of a patellar tendon graft.

Animals↗
PubMed2006

Repair of tendon defect with dermal fibroblast engineered tendon in a porcine model.

Harvesting autologous tenocytes for tendon engineering may cause secondary tendon defect at the donor site. Dermal fibroblasts are an easily accessible cell source and do not cause major donor site defect. This study aims to explore the possibility of tendon engineering using dermal fibroblasts. A total of 45 hybrid pigs were randomly divided into three groups: experimental group (n = 15)--repair of tendon defect with a dermal fibroblast engineered tendon; control group 1 (n = 15)--repair of defect with a tenocyte engineered tendon; and control group 2 (n = 15)-repair of defect with a scaffold alone. Both autologous dermal fibroblasts and tenocytes were seeded on polyglycolic acid (PGA) unwoven fibers to form a cell-scaffold construct and cultured in vitro for 7 days before in vivo implantation to repair a defect of flexor digital superficial tendon. Specimens were harvested at weeks 6, 14, and 26 for gross, histological, and mechanical analyses. Microscopy revealed good attachment of both dermal fibroblasts and tenocytes on PGA fibers and matrix production. In vivo results showed that fibroblast and tenocyte engineered tendons were similar to each other in their gross view, histology, and tensile strength. At 6 weeks, parallel collagen alignment was observed at both ends, but not in the middle in histology, with more cellular components than natural tendons. At weeks 14 and 26, both engineered tendons exhibited histology similar to that of natural tendon. Collagens became parallel throughout the tendon structure, and PGA fibers were completely degraded. Interestingly, dermal fibroblast and tenocyte engineered tendons did not express type III collagen at 26 weeks, which remained observable in normal pig skin and control group 2 tissue using polarized microscopy, suggesting a possible phenotype change of implanted dermal fibroblasts. Furthermore, both fibroblast and tenocyte engineered tendons shared similar tensile strength, about 75% of natural tendon strength. At 6 weeks in control group 2, neo-tissue was formed only at the peripheral area by host cells. A cord-like tissue was formed at weeks 14 and 26. However, the formed tissue was histologically disorganized and mechanically weaker than both cell-engineered tendons (p < 0.05). These results suggest that dermal fibroblasts may have the potential as seed cells for tendon engineering.

Absorbable Implants↗
PubMed2001

Ruptured Achilles tendons are significantly more degenerated than tendinopathic tendons.

OBJECTIVE: To ascertain whether there is an association between tendinopathic and ruptured Achilles tendons, hypothesizing that the histopathological aspects of tendinosis in tendinopathic tendons are less advanced than those found in ruptured Achilles tendons. METHODS: This was a comparative cohort study at a university teaching hospital. Histological examination was performed using hematoxylin and eosin and alcian blue/periodic acid-Schiff stained slides. The slides were interpreted using a semiquantitative grading scale assessing fiber structure, fiber arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, hyalinization, and glycosaminoglycan. We calculated a pathology score giving up to three marks for each of the above 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 ranging from 0.170 to 0.750 (kappa statistics). RESULTS: We studied biopsy samples from the Achilles tendon of patients undergoing open repair for a subcutaneous rupture of their Achilles tendon (N = 35; average age (+/- SD), 48.4 +/- 16.9 yr; range, 26-80), biopsy specimens from the Achilles tendon of patients undergoing exploration for Achilles tendinopathy (N = 13; average age, 35.7 +/- 12.9 yr; range, 18-67) and specimens of Achilles tendons from individuals with no known tendon pathology (N = 16; average age, 65 +/- 19.1 yr; range, 46-82). The highest mean score of ruptured tendons was significantly greater than that of tendinopathic tendons (17.4 +/- 4.9 vs 10.5 +/- 6.1, P < 0.001), and highest mean score of tendinopathic tendons was greater that that of control tendons (10.5 +/- 6.1 vs 5.9 +/- 7.3) (P < 0.001). CONCLUSION: Ruptured and tendinopathic tendons are histologically significantly more degenerated than control tendons. The general pattern of degeneration was common to the ruptured and tendinopathic tendons, but there was a statistically significant greater degree of degeneration in the ruptured tendons. It is therefore possible that there is a common, as yet unidentified, pathological mechanism that has acted on both of these tendon populations.

Achilles Tendon↗
PubMed2006

Volar dislocation of the extensor carpi ulnaris tendon on magnetic resonance imaging is associated with extensor digitorum communis tendon rupture in rheumatoid wrists.

PURPOSE: Extensor tendon rupture in rheumatoid wrists is a common problem and causes immediate dysfunction of the digits. The best treatment for tendon rupture may be prophylactic management, although the factors associated with tendon rupture must first be identified. The purpose of this study was to evaluate structures around rheumatoid wrists using magnetic resonance imaging with forearm rotation and to identify factors associated with extensor tendon rupture as indications for prophylactic surgery. METHODS: The subjects were 34 patients (40 wrists) with active rheumatoid arthritis. The extensor digitorum communis (EDC) tendons were ruptured in 15 wrists. Magnetic resonance imaging of the wrists was performed in maximally pronated and supinated positions of the forearm. Axial images of the distal radioulnar joints (DRUJs) were selected to evaluate DRUJ synovitis, dorsal tenosynovitis, volar dislocation of the extensor carpi ulnaris (ECU) tendon, sigmoid notch angle, and the radioulnar ratio (RUR) (ie, the degree of DRUJ subluxation). RESULTS: No significant correlations were found between EDC tendon rupture and DRUJ synovitis, dorsal tenosynovitis, or RUR in pronation. Extensor digitorum communis tendon rupture correlated significantly with volar ECU tendon dislocation, sigmoid notch angle, and RUR in supination. Radioulnar ratio correlated significantly with volar ECU tendon dislocation only in supination and not in pronation. Thus, DRUJ subluxation was advanced even in the supinated wrist with volar ECU tendon dislocation. As a factor associated with EDC tendon rupture, volar ECU tendon dislocation had 87% sensitivity and 76% specificity. CONCLUSIONS: Volar ECU tendon dislocation is associated with increased RUR in supination and EDC tendon rupture. Volar ECU tendon dislocation can thus be considered a factor associated with EDC tendon rupture, and its presence may indicate the need for prophylactic surgical intervention in a subset of rheumatoid arthritis patients.

Adolescent↗
PubMed2003

Effects of superficialis tendon repairs on lacerated profundus tendons within or proximal to the A2 pulley: an in vivo study in chickens.

PURPOSE: In a flexor tendon injury model in chickens we undertook a study to evaluate effects of the flexor digitorum superficialis (FDS) tendon repairs on excursions, work of flexion, and adhesions of the repaired flexor digitorum profundus (FDP) tendon after their injuries within or proximal to the equivalent of the A2 pulley and early tendon motion. METHODS: Thirty-five leghorn chickens were divided into 3 groups. In group 1 the FDS and FDP tendons of the long toes on both sides were transected in the area covered by the pulley. In group 2 the tendons were transected proximal to the pulley. In the first 2 groups, both tendons were repaired on the left feet, and only the profundus was repaired with superficialis excision on the right. The operated toes underwent simulated passive flexion for 3 weeks and results were evaluated 8 weeks after surgery. Chickens in group 3 were unoperated and served as the controls. RESULTS: When the tendons were cut within the pulley the FDP excursions and work of flexion were significantly better in the toes in which the FDS was excised than in those with both tendon repairs. When they were cut proximal to the pulley the repairs of both tendons had outcomes similar to that with excision of the FDS. Adhesions were more severe when both tendons were repaired under the pulley as compared with those after repair of a single tendon. CONCLUSIONS: This study showed different effects of the surgical repair or excision of the FDS on the FDP tendon within or proximal to a major pulley. Repair of both tendons worsens the gliding of the FDP tendon and increases adhesions within the major pulley; however, repair of both tendons yields outcomes equivalent to that after repair of only the FDP tendon proximal to the pulley.

Animals↗
PubMed2006

Abnormalities on MRI of the subscapularis tendon in the presence of a full-thickness supraspinatus tendon tear.

OBJECTIVE: Our objective was to determine the association between size and chronicity of full-thickness supraspinatus tendon tears with subscapularis tendon abnormalities on MRI. MATERIALS AND METHODS: One hundred forty-two MRI examinations with full-thickness supraspinatus tendon tears were categorized on the basis of the supraspinatus muscle (SS): normal muscle (SS(normal)), suggesting a recent or small tear; reduced muscle bulk without fatty atrophy (SS(volume loss)); and those with fatty atrophy, suggesting a large or chronic tear (SS(fatty atrophy)). Subscapularis tendon abnormalities, the subcoracoid interval, and subcortical bone marrow edema in the lesser tuberosity and coracoid process were recorded. RESULTS: The mean size of supraspinatus tendon tears in the SS(normal) (n = 45) group was 8.5 mm, 16.6 mm in SS(volume loss) (n = 53), and 29 mm in the SS(fatty atrophy) group (n = 44). Subscapularis tendon abnormality was identified in 22% of SS(normal) patients, 61% of SS(volume loss), and 86% of the SS(fatty atrophy) group (p < 0.001). There was moderate correlation between chronicity of supraspinatus tendon tears and subscapularis tendon abnormality (r = 0.47; p < 0.0001), with no correlation between the subcoracoid interval and abnormalities of the subscapularis tendon. There was moderate correlation between chronicity of supraspinatus tendon tears and bone marrow changes in the lesser tuberosity (r = 0.44; p < 0.0001). CONCLUSION: Subscapularis tendon abnormality is related to chronicity of supraspinatus tendon tears. Bone marrow edema in the lesser tuberosity with a subscapularis tendon abnormality suggests increased stress at the subscapularis tendon insertion with chronicity of full-thickness supraspinatus tendon tears. Lack of correlation with the subcoracoid interval indicates that anterior instability may be a more important contributing factor to subscapularis tendon abnormalities than static subcoracoid impingement in the setting of a full-thickness supraspinatus tendon tear.

Adult↗
PubMed2006

Tissue reactions of adenoviral, adeno-associated viral, and liposome-plasmid vectors in tendons and comparison with early-stage healing responses of injured flexor tendons.

PURPOSE: Delivery of growth factor genes that may substantially increase the healing rate of injured digital flexor tendons is a new application of gene therapy. Adenoviral, adeno-associated viral (AAV), and liposome-plasmid vectors have been used to deliver genes to tendons, but the tendon reactions to these vectors--particularly in contrast to the healing responses in the injured tendons--were unknown. This study was designed to compare the tissue reactions of the earlier-mentioned vectors in tendons with the healing responses of injured flexor tendons. METHODS: Forty-two flexor digitorum profundus tendons of 6 New Zealand white rabbits were used. Eighteen tendons were divided into 3 groups of 6 each and injected with different vectors: adenoviral vector, AAV2-luciferase vector, or pCMV-beta vector with liposome. Another 12 tendons were cut and repaired. At 3, 7, and 14 days, the tendons were harvested and stained with hematoxylin and eosin. Normal flexor tendons were harvested as controls. RESULTS: The tissue reactions of the liposome-plasmid vector in tendons were the most prominent among the 3 vectors tested. The adenoviral vector elicited a moderate degree of tissue reaction. The AAV2 vector caused remarkable reactions in epitenon but almost no reactions in endotenon. Early-stage tissue reactions were more robust in the injured tendons. Compared with early-stage inflammatory and healing responses, the reactions elicited by these vectors were less severe. CONCLUSIONS: The 3 gene delivery systems tested elicit less severe tissue reactions in flexor tendons compared with early-stage inflammatory changes in injured tendons. Adenoviral and AAV vectors elicit less severe tissue reactions than liposome-plasmid vectors. The AAV2 vector appears to cause almost no reaction in endotenon. In terms of tissue reactions, the adenoviral and AAV2 vectors, in particular AAV2, are suitable gene delivery systems for future gene transfer to the tendon in vivo.

Animals↗
PubMed2004

Calcium-phosphate-hybridized tendon directly promotes regeneration of tendon-bone insertion.

We developed a novel technique to improve tendon-bone attachment by hybridizing calcium phosphate (CaP) with tendons using an alternate soaking process. We characterized the deposited CaP on or in tendons and determined the healing process of anterior cruciate ligament (ACL) grafts by implanting CaP-hybridized free tendons in bone tunnels intra-articularly. Tendons to be implanted were alternately soaked 10 times in a Ca-containing solution and a PO(4)-containing solution for 30 s each. Treated tendons had ash contents threefold that of untreated tendons. Low-crystallinity apatite was found on or in treated tendons. In animal experiments, the CaP-hybridized tendon exhibited osteoclasts at the tendon-bone interface at 5 days after operation. At 2 weeks after operation, there were more osteoclasts and osteoblasts around the tendon than at 5 days after operation. Directly bonded areas were partially found between the implanted tendon and newly formed bone. The formation of a cartilage layer was partially apparent at 3 weeks after operation. The newly formed bone was observed almost around the tendon. We conclude that CaP-hybridized tendons clearly enhance the healing process of ACL grafts at the tendon-bone interface and regenerate a direct insertion-like formation of tendons similar to a normal healthy ACL insertion within 3 weeks after operation.

Animals↗
PubMed2005

Repeated exposure of tendon to prostaglandin-E2 leads to localized tendon degeneration.

OBJECTIVE: To determine whether repeated exposure of rabbit patellar tendon to prostaglandin-E(2) leads to degenerative changes in the tendon. SETTING: Laboratory animal study. MAIN OUTCOME MEASURES: Intratendinous changes including cellularity, matrix organization, collagen fibril packing, and diameter. METHODS: Skeletally mature New Zealand White rabbits (n = 10) were transcutaneously injected in the midsubstance of the patellar tendon with prostaglandin-E(2) (PGE(2); 50 ng or 500 ng). The contralateral tendons were used as 3 different controls (no injection, saline injection, and needlestick only). The injection was repeated once a week for 4 weeks, and the rabbits were killed 1 week after the last injection. The patellar tendons were harvested and examined using hematoxylin and eosin staining and transmission electron microscopy. RESULTS: Compared with the control groups, tendons exposed to PGE(2) by injection showed focal areas of hypercellularity, loss of normal tissue architecture, and focal areas of tendon disorganization and degeneration. Tendons injected with PGE(2) exhibited loosely organized collagen fibrils and had thinner collagen fibril diameter compared with control tendons (P < 0.005). Tendons injected with 500 ng PGE(2) appeared to be more disorganized and degenerated than those injected with 50 ng PGE(2). CONCLUSIONS: Repeated exposure of the tendon to PGE(2) leads to degenerative changes within the tendon. CLINICAL RELEVANCE: It is known that human tendon fibroblasts produce PGE(2) in vitro and in vivo in response to repetitive mechanical loading. This study demonstrates that repetitive exposure of the tendon to PGE(2) can result in degenerative changes within the tendon. Therefore, PGE(2) produced by tendon fibroblasts in response to repetitive mechanical loading in vivo might contribute to the development of exercise-induced tendinopathy.

Animals↗
PubMedDate not supplied

Ultrasonography for the diagnosis of diseases of the tendon and tendon sheath of the biceps brachii muscle.

OBJECTIVE: To describe the ultrasonographic appearance of the normal and diseased biceps brachii tendon and its tendon sheath in dogs. STUDY DESIGN: A prospective clinical study. ANIMALS: One hundred twenty client-owned dogs. METHODS: In the first part of the study, the ultrasonographic appearance of the normal biceps brachii muscle and the surrounding soft tissue was determined in 27 healthy dogs. Standard views were described and established. In the second part, 120 dogs with suspected pathology of the biceps brachii muscle were examined ultrasonographically. Fifty-five of these dogs had no sonographic changes, and 65 dogs had sonographically detectable pathologic changes of the tendon or the tendon sheath or both. The mean age of the affected dogs was 3.7 years. The ratio of males to females was 1.95:1. Sedation or anesthesia of the dogs was required because of the extreme movements of the leg necessary for the examination. To achieve a perpendicular view of the tendon and the tendon sheath, the area of the shoulder joint was rotated outward and abducted as far as possible. Examination of the muscle-tendon apparatus of the biceps brachii muscle was divided into 4 main sections. RESULTS: Linear transducers (7.5-10 MHz) allowed the soft tissue structures to be easily visualized with ultrasonography. Pathologic changes of the tendon and tendon sheath were visualized sonographically by using high-frequency linear probes. Partial or complete tendon rupture, medial luxation of the tendon, corpora libera in the tendon sheath, and tenosynovitis were clearly shown. CONCLUSIONS: High-frequency ultrasonography using linear transducers allows the examiner to accurately define the pathologic changes in the region of the biceps brachii tendon in dogs. CLINICAL RELEVANCE: The use of sonography for diagnosis of disease processes of the tendon and tendon sheath of the biceps brachii muscle complements clinical and radiographic examination findings.

Animals↗
PubMed2005

The response of the flexor digitorum longus and posterior tibial muscles to tendon transfer and calcaneal osteotomy for stage II posterior tibial tendon dysfunction.

BACKGROUND: The purpose of this prospective study was to evaluate the response of the flexor digitorum longus (FDL) and posterior tibial (PT) muscles to FDL tendon transfer and medial displacement calcaneal osteotomy for stage II posterior tibial tendon dysfunction (PTTD). METHODS: Twelve patients were divided into two groups, depending on whether the PT tendon was excised (Excised Tendon Group) or left intact (Intact Tendon Group). The muscle volumes of the FDL and PT muscles in both legs were measured and compared, using cross-sectional area (CSA) analysis of preoperative and postoperative MRI. RESULTS: Preoperatively, there was an average 11% reduction in the PT muscle volume and a 17% increase in the FDL muscle volume from the normal contralateral side in both groups. One year after surgery (average 13.4 months) in both groups, the FDL muscle volume had increased by an average of 27% and the PT muscle volume had decreased by 23% compared to the contralateral normal side. The FDL volume increased by 44% in the Excised Tendon Group compared to 11% in the Intact Tendon Group. The PT muscle volumes were not assessed in the Excised Tendon Group because all PT muscle had been replaced by fatty infiltration. The PT volumes in the Intact Tendon Group decreased further from a 6% reduction preoperatively to a 23% reduction postoperatively compared to the normal contralateral side. The American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot scores increased from 50 preoperatively to 88 at 1 year after surgery. There was no difference in the scores between the Excised Tendon (47 to 87) and Intact Tendon (53 to 89) groups. CONCLUSION: We concluded that the FDL muscle hypertrophies in response to a failing PT muscle. This hypertrophy continues after FDL transfer and medial displacement calcaneal osteotomy. With excision of the PT tendon, the FDL undergoes greater hypertrophy than if the tendon is left attached. The PT muscle continues to atrophy and undergoes complete fatty replacement if the tendon is excised. Transfer of the FDL and medial displacement calcaneal osteotomy produce a satisfactory improvement in hindfoot function; the outcome was the same whether the PT tendon was sacrificed or left intact.

Adult↗
PubMed2006

Tibialis anterior tendon and extensor retinaculum: imaging in cadavers and patients with tendon tear.

OBJECTIVE: Under the hypothesis that the anatomic relationship of the tibialis anterior tendon and extensor retinaculum of the foot and ankle is relevant to the clinical aspects of a tear in that tendon, we assessed the anatomic details of these structures using MRI in cadavers and evaluated MRI in patients with a tibialis anterior tendon tear. MATERIALS AND METHODS: Seven cadaveric feet underwent detailed MRI using standard and oblique coronal planes with respect to the course of the tibialis anterior tendon and extensor retinaculum. Cadaveric sections subsequently provided an anatomic correlation. MR images of seven patients with tibialis anterior tendon tear were analyzed by consensus of two musculoskeletal radiologists. RESULTS: Imaging-anatomic correlations allowed identification of the tibialis anterior tendon and extensor retinaculum. The tendon passed through three tunnels formed by the superior extensor retinaculum, oblique superomedial, and oblique inferomedial limbs of the inferior extensor retinaculum. Of seven patients with the tendon tear, three patients had complete tears and four patients had partial tears. In all partial tears, the level of the tear was at the ankle joint, corresponding to the approximate level of the oblique superomedial limb. In all complete tears, the proximal ends of torn tendons were retracted to a level below the oblique superomedial limb. In all tears, the oblique superomedial limb surrounding the torn tendon was seen with thickening in four patients and enhancement after IV gadolinium injection in two patients. Other findings included a bulbous appearance or swelling of the torn tendon in two complete and two partial tears and fluid collections within the tendon sheath and in an area confined by the extensor retinaculum in four patients. CONCLUSION: The relationship of the tibialis anterior tendon and extensor retinaculum is well depicted on MRI, even in patients with a tibialis anterior tendon tear, and is clinically relevant to the tear of this tendon.

Adult↗
PubMed1999

Changes in geometry of the finger flexor tendons in the carpal tunnel with wrist posture and tendon load: an MRI study on normal wrists.

OBJECTIVES: (1) To develop a methodology to determine the trajectories of the digital flexor tendons using MRI. (2) To examine changes in tendon trajectories due to wrist posture, with and without pinch force. (3) To calculate the radius of curvature of the flexor tendons and note implications for contact forces on the median nerve. (4) To assess the use of Landsmeer's models at the wrist. DESIGN: Finger flexor tendon centroids were digitized from magnetic resonance images of the carpal tunnel and the tendon paths were determined analytically. Radii of curvature were calculated from the tendon paths. BACKGROUND: Landsmeer's models of joint-tendon interaction (Landsmeer, 1961) have been used to determine moment arms and radius of curvature of the tendon paths about articulations. An explanation for a biomechanical cause of work-related carpal tunnel syndrome originated from these models. METHODS: Three healthy male participants had their right wrist scanned while splinted in four wrist postures (flexed to 20 degrees, 45 degrees, neutral, extended to 20 degrees ) with and without maintaining a 10 N pinch grip. 20-24 cross-sectional images were used for each condition. RESULTS: Volar movement of the tendons was seen with wrist flexion and the opposite was true with extension. Tendon intersection angles were calculated between the tendon as it entered the carpal tunnel and as it exited the tunnel and were 50-65% of the wrist angle (R(2)=0.81-0.96). The radius of curvature was smallest (mean=82-127 mm) with an active pinch grip with the wrist splinted at 45 degrees of flexion (mean actual wrist angle 37 degrees ). CONCLUSIONS: The radius of flexor tendon curvature is not constant as previously assumed and is larger than previous estimates. The addition of tendon force with the wrist flexed acts to reduce the radius of curvature which further increases the contact stress on the median nerve and other wrist structures. The use of MRI to determine the tendon paths has provided new insight into the relationships between the finger flexor tendons and other structures at the wrist. RELEVANCE: These findings provide data for biomechanical models of the carpal tunnel and predict the possible pathophysiology of work-related carpal tunnel syndrome.

Adult↗
PubMed1997

The distribution of cartilage oligomeric matrix protein (COMP) in tendon and its variation with tendon site, age and load.

A protein prominent in guanidine hydrochloride extracts of adult bovine and equine digital flexor tendons was confirmed to be Cartilage Oligomeric Matrix Protein (COMP) by non-reducing and reducing SDS-PAGE, reaction with rabbit anti-COMP polyclonal antiserum on Western blots, trypsin digestion followed by HPLC on a C2/C18 column, and identification of COMP mRNA from tendon on Northern blots. Immunohistochemistry and Western blots of extracts showed COMP to be present in all regions of digital flexor tendons. Equine tendon COMP was purified by ion exchange chromatography and gel filtration and used in a heterologous inhibition ELISA to quantify COMP in equine digital flexor tendons at different ages, and in other tendons and ligaments. Mean COMP levels in digital flexor tendon were approximately 2-5mg/g wet weight, but they showed a large variation. Levels were low in neonatal tendon but rose rapidly during growth, with the metacarpal (tensional) superficial digital flexor tendon having the highest levels (approximately 10mg/g wet weight). Levels subsequently declined in this region, while in areas which experience a variable amount of compression, levels increased less but then remained constant. Extensor tendons and collateral ligaments, which experience less loading in vivo, had levels similar to those in neonatal tendon. COMP was identified in scarred skin and granulation tissue but not in normal skin, chronic fibrosis, or a fibrosarcomatous skin growth. A unilateral non-weight-bearing growing animal contained three to six times more COMP in the weight-bearing digital flexor tendons compared to the paralyzed limb, while the extensor tendons had similar amounts in both limbs. With the recent discovery of a COMP gene mutation causing pseudoachondroplasia (Hecht et al., 1995), in which lax tendons and ligaments are a feature, the present data suggest that COMP is synthesized in response to, and is necessary for tendon to resist, load.

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