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At least 919 records · Page 51Linked to original sources
PubMed1987

Achilles tendon ruptures--peroneus brevis transfer.

Peroneus brevis tendon transfer has been utilized in 40 individuals during the last 13 years. All cases consisted of complete Achilles tendon ruptures. In 34 cases the rupture was in the distal one-third of the tendon substance, in four cases bony avulsion of the calcaneal tuberosity occurred, and in two cases there was a diffuse tear in the proximal two-thirds of the tendon near the musculotendinous junction. The middle-aged athlete sustained the majority of these injuries during sports. Eleven patients were less than 30 years old, 23 patients were 30 to 40 years old, and six were over 40 years old. Five patients had reruptures that involved prior nonoperative treatment of cast immobilization, and one had undergone simple direct suture. This repair has been used in acute, chronic, and recurrent ruptures of the tendoachillis. Thirty-three patients presented within 1 week of injury, and seven after more than 1 week. A. Perez Teuffer personally described the preferred technique in 1971 and subsequently published in 1978. The transfer of the peroneus brevis is combined with a direct end-to-end suture of the triceps surae tendon that allows a secure reconstruction with the foot at a right angle. The peroneus brevis tendon is detached from the base of the fifth metatarsal and then tunnelled through the distal Achilles tendon stump. The distal portion of the tendon transfer is then drawn proximally along the medial calcaneal tendon border. The proximal triceps surae tendon is pulled distally and secured to the peroneal tendon.(ABSTRACT TRUNCATED AT 250 WORDS)

Achilles Tendon↗
PubMed2003

[Management of sheath after repair of double tendons in zone II d].

OBJECTIVE: To evaluate the management of sheath after repair of double tendons in clean-cut injury or severe injury in zone II d. METHODS: Forty-eight white leghorn chickens were divided into 4 groups. Both FDS and FDP tendons in zone II d of long toes were repaired with modified Kessler suture after tendon transection in group A (clean-cut tendon injury, sheath closure), group B (clean-cut tendon injury, sheath excision), group C (severe tendon injury, sheath closure) and group D (severe tendon injury, sheath excision), respectively. Biomechanical studies of gliding excursion and work of flexion were carried out 6 weeks and 12 weeks after tendon repair. The extent of adhesion was examined. RESULTS: After 6 and 12 weeks of repair, there were no significant differences in tendon excursion and work of flexion of the toes between groups A and B. Excursions of FDP tendons in group D was significantly larger than that in group C (P < 0.05). Work of flexion and extent of adhesion in group D was significantly less than that in group C (P < 0.05). CONCLUSION: The above results indicate that sheath can be closed after repair of both FDS and FDP tendons in clean-cut injury and that sheath should be excised in severe injury in zone II d.

Animals↗
PubMed1985

Results of flexor tendon surgery in zone II.

In this article we have attempted to analyze the results of Zone II flexor tendon repair, staged flexor tendon reconstruction, and tenolysis based on cases taken from a single hand surgical practice. Formulas have been offered to determine the percentage return of motion at the PIP and DIP joints utilizing the total active and passive motion measurements. Variation in the formulas for each procedure are necessitated by the preoperative active and passive motion. A common classification system based on the percentage return following each procedure has also been utilized. By employing these assessment methods on digits of our patients who underwent flexor tendon repairs, we achieved the following results: Digits undergoing primary flexor tendon repair in Zone II with postoperative controlled passive motion techniques returned 56 per cent excellent or good function, with 13 per cent in the poor category and 4 per cent experiencing tendon rupture. Staged flexor tendon reconstruction returned 40 per cent excellent or good results with 66 per cent categorized as excellent, good, or fair. Twenty-eight per cent remained in the poor classification, with 7 per cent having ruptures. These results were substantially upgraded by tenolysis of the tendon grafts following Stage II in 47 per cent of all digits. Tenolysis was an effective procedure following a repair or graft and was found to return 67 per cent excellent or good results when carried out for adherent tendon repairs, with 10 per cent in the poor category and an 8 per cent rupture rate. A 65 per cent excellent or good return followed tenolysis of flexor tendon grafts, with 12 per cent judged poor and 8 per cent incidence of rupture. An analysis of the theoretical results of 100 consecutive Zone II flexor tendon repairs following multiple procedures for those digits that had unsatisfactory initial results indicated that, under ideal circumstances, as high as 96 per cent of all digits might be expected to return flexor performance in the excellent or good categories. I acknowledge that the results of flexor tendon procedures are strongly influenced by a wide array of factors, including the patient's age and motivation, the preoperative status of the digit, surgical technique, and postoperative management. An effort has been made here to minimize the variables by including patients taken from a single hand surgical practice and managed, to a large extent, by the same surgeon.(ABSTRACT TRUNCATED AT 400 WORDS)

Finger Joint↗
PubMed1980

Cell morphology and collagen types in equine tendon scar.

The histological appearance of cells and tissues in the reparative scar tissue which forms in the equine superficial flexor tendon following partial rupture was compared to that of normal tendon. The repair fibroblasts were found to be larger and more basophilic than the tenocytes of normal tendon, to have large vesicular nuclei and to resemble the 'myofibroblasts' described in scar tissue elsewhere. The cell to matrix ratio in scarred zones of tendon was found to be increased and the concentration of collagen in these areas was less than in normal tendon. However, the scar tissue collagen was more readily extractable and contained a different pattern of collagen types. Normal equine tendon was found to be composed almost exclusively of type I collagen whereas the scarred tendon had substantial quantities (20 to 30 per cent) of type III collagen in addition to type I. The presence of type III collagen in the scarred tendon was confirmed by indirect immunofluorescence using antibodies to purified type III collagen. These observations suggest that tendon scar tissue is not derived from proliferating tenocytes but from mesenchymal cells resting in peritendinous connective tissue or blood vessels. As a result of the presence of type III collagen, the scarred tendon is also likely to have less tensile strength than normal tendon.

Animals↗
PubMed1995

[Flexor tendon repair: timing of surgery and sheath management].

Effect of timing of repair and management of sheath on functions of injuried tendons was evaluated in a clinical relevant model using 60 white leghorn chickens. The flexor digitorum profundus (FDP) tendons of the long toes were cut and were repaired at 1, 4, 8, 14 and 20 days after injury. The sheath on the left foot was closed and that on the right excised. The tendon excursion, toe motion, morphology of the sheath and tendon healing were studied 6 weeks after tendon repair. Tendon functions were the best in primary repair, and they got worse as the delay became longer. Repair in the late stage produced significantly worse tendon functions. Sheath closure with remarkable tension worsened tendon healing. We conclude that the optimal timing for tendon repair is at the primary stage. Delayed tendon repair can be performed within 3 weeks to one month after injury, but the repair is preferably done in initial several days of delay. Direct sheath closure is not advocated in tendon repair in the delayed period.

Animals↗
PubMed1999

Fibrocartilage in the extensor tendons of the human metacarpophalangeal joints.

The extensor tendons of the fingers cross both the metacarpophalangeal (MCP) and interphalangeal joints. Previous studies have shown that where the extensor tendons replace the capsule of the proximal interphalangeal (PIP) joint, they contain a sesamoid fibrocartilage that articulates with the proximal phalanx during flexion. The fibrocartilage labels immunohistochemically for a variety of glycosaminoglycans and collagens. In the current study, we investigate the molecular composition of the extensor tendons at the level of the MCP joints. This is of particular interest because the tendon has a greater moment arm at this location (and might thus be subject to greater compression), but is separated from the joint cavity by the capsule and peritendinous tissue. Six hands were removed from elderly cadavers (39-85 years of age) and the MCP joints were fixed in 90% methanol. The extensor tendons were dissected from all fingers, cryosectioned, and immunolabelled with a panel of monoclonal and polyclonal antibodies for types I, II, III, and VI collagens, chondroitin 4 and 6 sulphates, dermatan, and keratan sulphate and aggrecan. Antibody binding was detected with the Vectastain ABC 'Elite' avidin/biotin/peroxidase kit. The extensor tendons in all the fingers had a metachromatic sesamoid fibrocartilage on their deep surface which immunolabelled for types I, III, and VI collagens, and for all glycosaminoglycans and aggrecan. Labelling for type II collagen was also seen in some fibrocartilages and was a constant feature of all index fingers. This probably relates to the greater use of that digit and the higher loads to which its tendons are subject. Chondroitin 6 sulphate and type II collagen are the most consistent markers of the fibrocartilage phenotype and most of the chondroitin 6 sulphate is probably associated with aggrecan. It is concluded that the labelling profile of the tendon fibrocartilage in the different fingers at the MCP joints is broadly similar to that at the PIP joints. Thus, the potentially greater level of compression on the extensor tendons may be counterbalanced by the lack of fusion of the tendon with the joint capsule. It is suggested that the maintenance of a similar level of fibrocartilage differentiation at two different points along the length of the extensor tendon ensures that the tensile strength is the same in the two regions and that no weak link is present.

Adult↗
PubMed2002

Surface modification of extrasynovial tendon by chemically modified hyaluronic acid coating.

We investigated a method for chemically binding hyaluronic acid (HA) to extrasynovial tendon and the effect of chemically modified HA on the gliding resistance of tendon. Canine peroneus longus (PL) tendons were immersed into one of three different solutions (saline, 1% HA, or 1% chemically modified HA) for 2 h. The gliding resistance of treated PL tendons was measured at 1, 5, 10, 20, 50, and 100 cycles in a saline bath. After treatment with unmodified HA and chemically modified HA, the gliding resistance of the PL tendons decreased significantly compared with the saline-treated tendons (p < 0.05), and this effect of the two HA treatments persisted through 10 cycles. For cycles 20-100, the gliding resistance of PL tendons treated with chemically modified HA remained significantly lower than that of tendons treated either with saline or unmodified HA (p < 0.01). The effect of paratenon removal on gliding resistance was neither statistically significant for repetitions beyond 10 cycles, nor was it an independent predictor of gliding resistance, as the effect (higher resistance after paratenon removal) was mainly seen in the saline-treated tendons. Chemically modified HA-treated extrasynovial tendons may improve gliding of tendon graft and reduce adhesion postoperatively, compared with traditional grafts.

Animals↗
PubMed2006

Decorin regulates assembly of collagen fibrils and acquisition of biomechanical properties during tendon development.

Tendon function involves the development of an organized hierarchy of collagen fibrils. Small leucine-rich proteoglycans have been implicated in the regulation of fibrillogenesis and decorin is the prototypic member of this family. Decorin-deficient mice demonstrate altered fibril structure and mechanical function in mature skin and tail tendons. However, the developmental role(s) of decorin needs to be elucidated. To define these role(s) during tendon development, tendons (flexor digitorum longus) were analyzed ultrastructurally from postnatal day 10 to 90. Decorin-deficient tendons developed abnormal, irregularly contoured fibrils. Finite mixture modeling estimated that the mature tendon was a three-subpopulation mixture of fibrils with characteristic diameter ranges. During development, in each subpopulation the mean diameter was consistently larger in mutant mice. Also, diameter distributions and the percentage of fibrils in each subpopulation were altered. Biomechanical analyses demonstrated that mature decorin-deficient tendons had significantly reduced strength and stiffness; however, there was no reduction in immature tendons. Expression of decorin and biglycan, a closely related family member, was analyzed during development. Decorin increased with development while biglycan decreased. Spatially, both had a comparable localization throughout the tendon. Biglycan expression increased substantially in decorin-deficient tendons suggesting a potential functional compensation. The accumulation of structural defects during fibril growth, a period associated with decorin expression and low biglycan expression, may be the cause of compromised mechanical function in the absence of decorin. Our findings indicate that decorin is a key regulatory molecule and that the temporal switch from biglycan to decorin is an important event in the coordinate regulation of fibrillogenesis and tendon development.

Animals↗
PubMed1999

In vivo finger flexor tendon force while tapping on a keyswitch.

Force may be a risk factor for musculoskeletal disorders of the upper extremity associated with typing and keying. However, the internal finger flexor tendon forces and their relationship to fingertip forces during rapid tapping on a keyswitch have not yet been measured in vivo. During the open carpal tunnel release surgery of five human subjects, a tendon-force transducer was inserted on the flexor digitorum superficialis of the long finger. During surgery, subjects tapped with the long finger on a computer keyswitch, instrumented with a keycap load cell. The average tendon maximum forces during a keystroke ranged from 8.3 to 16.6 N (mean = 12.9 N, SD = 3.3 N) for the subjects, four to seven times larger than the maximum forces observed at the fingertip. Tendon forces estimated from an isometric tendon-force model were only one to two times larger than tip force, significantly less than the observed tendon forces (p = 0.001). The force histories of the tendon during a keystroke were not proportional to fingertip force. First, the tendon-force histories did not contain the high-frequency fingertip force components observed as the tip impacts with the end of key travel. Instead, tendon tension during a keystroke continued to increase throughout the impact. Second, following the maximum keycap force, tendon tension during a keystroke decreased more slowly than fingertip force, remaining elevated approximately twice as long as the fingertip force. The prolonged elevation of tendon forces may be the result of residual eccentric muscle contraction or passive muscle forces, or both, which are additive to increasing extensor activity during the release phase of the keystroke.

Adult↗
PubMed2006

Ibuprofen inhibition of tendon cell migration and down-regulation of paxillin expression.

Sports-related tendon injuries are commonly treated with nonsteroidal antiinflammatory drugs. Tendon healing requires migration of tendon cells to the repair site, followed by proliferation and synthesis of the extracellular matrix. This study was designed to determine the effect of ibuprofen on the migration of tendon cells intrinsic to rat Achilles tendon. Whether a correlation exits between this effect and the expression of paxillin, which is a positive regulator of cell spreading and migration, was also investigated. The migration of tendon cells was evaluated ex vivo by counting the number of initial outgrowths from the tendon explants and in vitro by transwell filter migration assay. The spreading of tendon cells in culture was also evaluated microscopically. The mRNA and protein expressions of paxillin were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. Dose-dependent ibuprofen inhibition was demonstrated on the migration of tendon cells both ex vivo, and in vitro. Similar inhibition was also observed on the spreading of tendon cells. Suppression of mRNA expression and protein level of paxillin was revealed by RT-PCR and Western blot analyses. The expression of focal adhesion kinase (FAK) and tyrosine phosphorylation of FAK remained unchanged. In conclusion, ibuprofen inhibits tendon cell migration in a process that is probably mediated by the down-regulation of paxillin.

Achilles Tendon↗
PubMed2006

Extracellular matrix scaffolds are repopulated by bone marrow-derived cells in a mouse model of achilles tendon reconstruction.

The extracellular matrix derived from porcine small intestinal submucosa (SIS-ECM), an FDA-approved material currently used clinically for rotator cuff repair, has been shown to attract bone marrow-derived cells during in vivo remodeling of a subcutaneous implant and produce chemoattractant peptides following chemical degradation in vitro. The purpose of the present study was to determine if bone marrow-derived cells participate in the long-term remodeling of the Achilles tendon in a mouse model when repaired with SIS-ECM. A 2-mm gap was produced in the Achilles tendon of 40 chimeric mice produced to express green fluorescent protein (GFP) in all of their bone marrow-derived cells. Tendons were repaired by replacing the resected section with autologous tendon tissue or with a single layer sheet of lyophilized SIS-ECM. Four animals from each treatment group were sacrificed at 1, 2, 4, 8, and 16 weeks, and sections were harvested for histologic and fluorescence microscopy. Both groups showed accumulation of GFP-expressing marrow-derived cells at the site of tendon remodeling at 1 and 2 weeks that were associated with areas of angiogenesis and inflammation. By 16 weeks, the SIS-ECM-treated group showed GFP expressing cells throughout the remodeled tendon in the absence of any inflammatory response, while the autologous tendon repair group showed no GFP expressing cells within the tendon except for occasional cells in the lumen of blood vessels. An SIS-ECM scaffold used for tendon repair recruits a population of bone marrow-derived cells that participates in the long-term remodeling process. The ability of SIS-ECM to recruit a population of marrow-derived cells to the remodeling site may alter the default mechanism of tendon healing. The involvement of these cells in the remodeling process may explain in part the process of site specific constructive remodeling as opposed to scar tissue formation when the ECM is used as a biologic scaffold for tendon reconstruction.

Achilles Tendon↗
PubMed2006

Optimization of surface modifications of extrasynovial tendon to improve its gliding ability in a canine model in vitro.

Previous studies have shown that the carboxyl groups in hyaluronic acid (HA) could be activated by 1-ethy 1-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) to form intermediate O-acylisoureas, which can chemically bind to exposed amino groups on the tendon surface, leading to improved gliding ability. However, the optimal ratio and concentrations of the components in this chemical mixture were not investigated. The purpose of this study was to optimize the constituents of this tissue engineering approach to tendon surface modification, to reduce friction and improve durability. Peroneus longus (PL) tendons (n=40) were harvested from adult mongrel dogs along with the A2 pulley obtained from the ipsilateral hind paw. After the gliding resistance of the normal PL tendon was measured, the tendons were treated under varying concentrations of HA (0.5, 1, and 2%) and EDC/NHS (0.05, 0.25, and 1%) mixed with a 10% gelatin. Tendon friction was measured for 1000 cycles of simulated flexion/extension motion. Following testing, the residual HA on the tendon surface was evaluated by immunohistochemisty. The gliding resistance of the untreated PL tendons had a mean value of 0.087+/-0.021 N. After surface treatment, there was no significant difference in friction due to HA concentration alone, but the concentration of EDC/NHS and the interaction between HA concentration and EDC/NHS concentration had a significant effect on friction. Regardless of HA concentration, the friction after 1000 cycles was significantly decreased in preparations which included a 1% concentration of EDC/NHS. The tendons with lower gliding resistance presented a smoother surface on light microscopy and maintained more residual HA on the tendon surface. By varying the relative concentrations of HA, EDC, and NHS it is possible to optimize the effect of surface treatment on friction and durability in a canine extrasynovial tendon in vitro.

Animals↗
PubMed2007

Tendons and ligaments are anatomically distinct but overlap in molecular and morphological features--a comparative study in an ovine model.

Tendons and ligaments are similar in composition but differ in function. Simple anatomical definitions do not reflect the fact individual tendons and ligaments have unique properties due to their adaptation to a specific role. The patellar tendon is a structure of particular clinical interest. A null hypothesis was declared stating that the patellar tendon is not significantly different in terms of matrix composition and collagen fibril diameter to other tendons. The lateral and medial collateral ligaments (LCL, MCL), anterior and posterior cruciate ligaments (ACL, PCL), together with the long digital extensor, superficial digital extensor, and patellar tendons (LDET, SDFT, PT) were harvested from three cadaveric ovine hindlimbs. The extracellular matrix was assessed in terms of water, collagen, and total sulphated glycosaminoglycan (GAG) content. The organization of the collagen component was determined by an ultrastructural analysis of collagen fibril diameter distributions, together with values for the collagen fibril index (CFI) and mass-average diameter (MAD). There were significant differences between ligaments and tendons. The PT had a bimodal collagen fibril diameter distribution with CFI 72.9%, MAD 202 nm, water content 53.1%, GAG content 2.3 microg/mg, and collagen content 73.7%, which was not significantly different from the other tendons. The results of this study support the null hypothesis suggesting that the patellar tendon is similar to other tendons and demonstrate that tendons have different characteristics to ligaments.

Animals↗
PubMed2000

Changes in ADC caused by tensile loading of rabbit achilles tendon: evidence for water transport.

Water diffusion measurements were performed on rabbit Achilles tendons during static tensile loading and tendons in an unloaded state. The apparent diffusion coefficient (ADC) was measured along two directions: parallel and perpendicular to the long axis of the tendon. Tendons were studied after being prepared in two ways: (a) after being stored frozen in phosphate-buffered saline (PBS) and (b) freshly isolated. Statistically significant directional anisotropy was observed in the ADC in all tendons. The ADC was significantly greater in the direction parallel to the long axis of the tendon than in the perpendicular direction. The anisotropy is attributed to the greater restrictions seen by the water molecules in the perpendicular direction and is consistent with the known geometry of the tendon. Storage in PBS caused tendons to swell. This increased the ADC measured along both directions and reduced the anisotropy. The existence of anisotropy in the ADC was not related to the orientation of the specimen in the magnet. The ADC increased along both directions following the application of a 5-N tensile load; the increase was greatest along the perpendicular axis of the tendon. In order to determine whether load-related changes in the ADC reflected changes in interfibrilar spacing, we used electron microscopy to measure load-related changes in fibril spacing. Load-related changes in fiber spacing could not account for the observed changes in the ADC. The increase in ADC caused by loading was attributed to the extrusion of tendon water into a bulk phase along the outside surface of the tendon. In PBS-stored samples, enough fluid was extruded that it could be visualized. The transient response of the ADC to a 5-N tensile load was also studied. The absolute ADC in both directions increased with loading and recovered to baseline upon unloading. The transient changes in ADC, for both loading and unloading, had a mean time constant of approximately 15 min. The magnitude of the load-induced transient ADC changes was comparable to that seen in the static-loading experiments.

Achilles Tendon↗
PubMed1993

Morphometry of the semitendinosus and gracilis tendons with application to anterior cruciate ligament reconstruction.

The length and cross-sectional area of human semitendinosus and gracilis tendons were measured in both single- and multi-strand configurations for the purpose of anterior cruciate ligament graft preparation. The average lengths of the semitendinosus and the gracilis tendons were 235 +/- 20 mm (mean +/- SD) and 200 +/- 17 mm, respectively. The cross-sectional area of a doubled semi-tendinosus tendon (two strands) was significantly less than that of a 10-mm-wide patellar tendon graft (P < 0.001). The cross-sectional area of the tripled semitendinosus tendon (three strands) and the 10-mm-wide patellar tendon were similar. Doubling of the combined semitendinosus and gracilis tendons (four strands) and tripling of this combination (six strands) resulted in a significantly greater cross-sectional area in comparison to the 10-mm-wide patellar tendon (P < 0.05, four strands; P < 0.001 six strands). This investigation demonstrates that anterior cruciate ligament grafts fashioned using multiple-strand combinations of the semitendinosus and gracilis tendons result in a cross-sectional area that is comparable to the bone-patellar tendon-bone graft. This is an important finding since cross-sectional area reflects the intra-articular volume of collagenous tissue. This information should be helpful to surgeons considering using the hamstring tendons as an anterior cruciate ligament graft.

Aged↗
PubMed1990

Relations between identified tendon organs and motor units in the medial gastrocnemius muscle of the cat.

In one medial gastrocnemius muscle of each of several cats, the response was recorded of a single tendon organ to the contraction of a single motor unit which strongly excited the receptor. The motor unit was depleted of its glycogen and the depleted muscle fibres identified in PAS-stained transverse sections. The site of maximum tendon organ sensitivity was marked and the tendon organ identified in the same sections. Five pairs of tendon organs and motor units were studied completely. Each tendon organ was found to have one or two (mean 1.6) depleted muscle fibres attached to it, included in the bundle of fibres attached to the end (mean no. 14.4) and side (mean no. 5.6) of the tendon organ. A correlation was found between tendon organ discharge rate and the tension calculated from cross-sectional area measurements of the depleted muscle fibres attached to the tendon organ, with variation between individual pairs of tendon organs and motor units. One estimate of the average sensitivity of the sample was 28 imp/s/mN. A nearly linear discharge rate vs. tension relation was found for single tendon organ and motor unit pairs when tension was graded during a series of fatiguing contractions. Under these conditions the sensitivity, measured as the slope of the relation between discharge rate and motor unit tension recorded at the common tendon, varied between 0.11 and 0.30 imp/s/mN for 6 pairs.

Animals↗
PubMed1999

[Replacement of the anterior cruciate ligament. Biomechanical studies for patellar and semitendinosus tendon fixation with a poly(D,L-lactide) interference screw].

Anterior cruciate ligament (ACL) reconstruction using autologous hamstring tendons are being performed more frequently and satisfactory results have been reported. Advantages such as low donor site morbidity and ease of harvest as well as disadvantages like low initial construct stiffness have been described. Recently, it has been demonstrated that graft fixation close to the original ACL insertion sites increases anterior knee stability and graft isometry. Hamstring tendon fixation techniques using interference screws offer this possibility. To reduce the risk of graft laceration, a round threaded titanium interference screw (RCI) was developed. To improve initial fixation strength, fixation techniques for hamstring tendons with separate or attached tibial bone plugs were introduced. However, data on fixation strength do not yet exist. With respect to the proposed advantages of biodegradable implants, like undistorted magnetic resonance imaging, uncompromised revision surgery and a decreased potential of graft laceration during screw insertion, we performed pullout tests of round threaded biodegradable and round threaded titanium interference screw fixation of semitendinosus (ST) grafts with and without distally attached tibial bone plugs. Data were compared with bone-tendon-bone (BTB) graft fixation using biodegradable and conventional titanium interference screws. We used 56 proximal calf tibiae to compare maximum pullout force, screw insertion torque, and stiffness of fixation for biodegradable direct ST tendon and bone plug fixation (group I: without bone plug, group II: with bone plug) versus titanium interference screw fixation (group III: without bone plug, group IV: with bone plug). A round threaded biodegradable poly-(D, L-lactide) (Sysorb) and a round threaded titanium interference screw (RCI) were used. As a control calf bone-tendon-bone (BTB) grafts fixed with either poly-(D, L-lactide) (group V) or conventional titanium (group VI) interference screws were used. ST tendons were harvested either with or without their distally attached tibial bone plugs from human cadavers and were folded to a three-stranded graft. Specimen were loaded in a material testing machine with the applied load parallel to the long axis of the bone tunnel. Maximum pullout force of ST bone plug (group III: 717 N +/- 90, group IV: 602 N +/- 117) fixation was significantly higher than that of direct tendon (group I: 507 N +/- 93, group III: 419 N +/- 77) fixation. Maximum pullout force of biodegradable screw ST fixation was higher than that of titanium screw fixation in both settings. There was no significant difference in pullout force between biodegradable (713 N +/- 210) and titanium (822 N +/- 130) BTB graft fixation or between ST fixation with bone plug and biodegradable screw with BTB fixation. Pullout force of hamstring tendon interference screw fixation can be improved by using a biodegradable implant. In addition, initial pullout force can be greatly improved by harvesting the hamstring tendon graft with its distally attached tibial bone plug. This may be important, especially in improving tibial graft fixation. This study encourages further research in tendon-bone healing with direct interference screw fixation to confirm the potential of this advanced method.

Anterior Cruciate Ligament↗
PubMed2003

Chronic Achilles tendon pain treated with eccentric calf-muscle training.

Injuries involving the Achilles tendon and manifested as chronic tendon pain are common, especially among recreational athletes. In a pilot study on a small group of patients with chronic painful mid-portion Achilles tendinosis, eccentric calf-muscle training was shown to give good clinical results. The aim of this prospective study was to investigate if the previously achieved good clinical results could be reproduced in a larger group of patients, and also to investigate the effects of eccentric calf-muscle training in patients with chronic insertional Achilles tendon pain. Seventy-eight consecutive patients, having chronic painful Achilles tendinosis at the mid-portion (2-6 cm level) in a total of 101 tendons (55 unilateral and 23 bilateral), and thirty consecutive patients with chronic insertional Achilles tendon pain in 31 tendons (29 unilateral and one bilateral) were treated with eccentric calf-muscle training for 12 weeks. Most patients were recreational athletes. Evaluation of the amount of tendon pain during activity was recorded on a visual analogue scale (VAS), before and after treatment. In 90 of the 101 Achilles tendons (89%) with chronic painful mid-portion Achilles tendinosis, treatment was satisfactory and the patients were back on their pre-injury activity level after the 12-week training regimen. In these patients, the amount of pain during activity, registered on the VAS-scale (mean+/-SD), decreased significantly from 66.8+/-19.4 to 10.2+/-13.7. On the contrary, in only ten of the tendons (32%) with chronic insertional Achilles tendon pain was treatment satisfactory, with a significant decrease on the VAS-scale (mean+/-SD), from 68.3+/-7.0 to 13.3+/-13.2. Our conclusion is that treatment with eccentric calf-muscle training produced good clinical results in patients with chronic painful mid-portion Achilles tendinosis, but not in patients with chronic insertional Achilles tendon pain.

Achilles Tendon↗