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Canine cadaveric study of flexor tendon repair using tendon splint: tensile strength and the work of flexion.

A total of 128 flexor tendon repairs in zone II were performed with various suture techniques using a canine cadaver model to determine the tensile strength, gap strength, and resistance to tendon gliding as measured by the work of flexion. The ultimate tensile strength in kilogram force (kgf) following tendon laceration and repair was the greatest after repair by the Savage technique (4.84 kgf) and the dorsal tendon splint technique (4.89 kgf), while the standard Kessler technique showed a strength of only 1.48 kgf. The greatest gap strength values were also obtained for the Savage and dorsal tendon splint techniques. The work of flexion increase was the greatest at 85.5% after repair using a mesh sleeve technique. While, the Savage and dorsal tendon splint techniques showed an increase of 24.3% and 25.1% with no significant difference compared to the other technique studied. Considering the values of these biomechanical parameters, we believe that the best flexor tendon repair techniques in the canine model are the Savage and dorsal tendon splint.

Animals↗

[Ultrastructural observation of tendonization of artificial tendon 109HH in rabbit].

Ten New Zealand rabbits were divided into 5 groups at random. Calcaneal tendons were cut bilaterally, then atificial tendon 109HH was used to connect the two ends of the cut tendon. Ultrastructural changes of control group and experimental groups at 2, 6, 12, 28 weeks after section were observed. The results showed that fibroblast proliferated and a lot of ribosome and RER appeared in plasm during 2 approximately 6 weeks, indicating artificial tendon caused fibroblast proliferation. During this period, fibroblast over synthesized collagenous protein and the synthesis of collagenous fibers peaked. During 12-28 weeks, the number of fibroblasts and the synthesis of collagenous protein decreased. Finally, fibroblasts became inactive tendon cells. With the formation of new tendons, the artificial tendens were degradated and absorbed, and disappeared after 12 weeks. The new tendon fibers became thicker and had the correct direction through reconstruction. The structure and function of new tendons could be restored to be consistent with normal values.

Animals↗

Single-stage Achilles tendon reconstruction using a composite sensate free flap of dorsalis pedis and tendon strips of the extensor digitorum longus in a complex wound.

The reconstruction of the posterior heel including a wide defect of the Achilles tendon is difficult as a result of complicated infection, deficient soft tissue for coverage, and functional aspects and defects of the tendon itself. As a single-stage procedure, various methods of tendon transfer and tendon graft have been reported along with details of local flaps or island flaps for coverage. With advances in microsurgical techniques and subsequent refinements, several free composite flaps, including tendon, fascia, or nerve, have been used to reconstruct large defects in this area without further damaging the traumatized leg. The authors report such a single-stage reconstruction of a composite Achilles tendon defect using the extensor digitorum longus tendon of the second to fourth toe in combination with a dorsalis pedis flap innervated by the superficial peroneal nerve. The follow-up of this case has proved a satisfactory outcome to date.

Achilles Tendon↗

Achilles tendon injury. Tendon elongation and soleus muscle fine structure in rabbit after different therapies.

Unilateral tenotomy of the Achilles tendon was carried out in 60 rabbits. The limb was then either mobilized directly or immobilized for 10 to 35 days using a plaster usually after tendon suture. In certain cases the plaster was removed early (on the 7th or 16th day) and the animals were than allowed to use this leg. Separation between tendon ends was apparent from steel markers, placed close to each cut end of the tendon and examined by X-ray. The separation curve was biphasic and both the first and the inactive phase reflected the degree of tension over the tendon suture. However, during the second separation phase, which began between the 17th and 21st day, the separation gradually reached the same level in all groups. Enzyme histochemistry and electron microscopy revealed severe degenerative changes in immobilized and in shortened muscles. Furthermore, a gradual shift in fibre type characteristics from type 1 slow-twitch fibres towards type 2 fast-twitch fibres occurred. Rapid recovery followed removal of the plaster. The findings indicated that both degenerative and regenerative processes and adaptive processes had been initiated in all experimental muscles when the tendon continuity was broken. The adaptive processes progressed gradually during the five-week post-operative period and might have been responsible for the second phase of the tendon end separation. The fibre adaptation, i.e. the transformation, may be accounted for by changes in structure of the myofibrils and composition of the myosin molecules.

Achilles Tendon↗

[Value of sonography to monitor the course of Achilles tendon rupture after treatment--comparison of conservative therapy, percutaneous tendon adaptation, and open suture].

In this prospective study,73 patients (with an average age of 36 years) were examined by ultrasound to compare the results of open Achilles tendon surgery, percutaneous tendon adaptation, and conservative treatment. Once the accident reports had been collected, all of the patients presented themselves at the Sportklinik Stuttgart at intervals of 4, 8, 12, 26 weeks, and approx. 2.5 years after the accident. During the course of these examinations, the thickness and structure of the tendon was quantified via ultrasound and the quality by clinical examination. The results of the ultrasonic quantification of the healing process appeared to be similar in all patients. On the day of the accident the thickness of the tendon was 9.3 mm. Four weeks later a remarkable regeneration could be seen in all patients (12.0 mm), which reached a maximum (16.7 mm) after 26 weeks. By the end of the study, however, the result was a scarred and thickened tendon of 11.5 mm. The comparison of the ultrasound results and the clinical examination after 26 weeks and 2.5 years showed no correlation between the value of the echo structure and functionality of the tendon, and the comparison between the different therapy groups showed no significant difference in the healing process either. In conclusion, ultrasound examination is able to provide information concerning the stage of the healing process. The quality of the healing and healed Achilles tendon and the relationship to their function cannot be studied with ultrasound, and this is not influenced by the choice of therapy.

Achilles Tendon↗

Tendon excursion and dehiscence during early controlled mobilization after flexor tendon repair in zone II: an x-ray stereophotogrammetric analysis.

The effect of different methods on early controlled mobilization of the flexor profundus tendon regarding tendon excursion and dehiscence was examined during treatment of 20 tendons in 18 patients. An application of radiographic stereophotogrammetric analysis on movements of tendon tissue was developed and the tendons studied during the early postoperative period. Considerable differences of tendon excursion were found between the various mobilization methods and were dependent on the level of injury within zone II. The use of a mobilization method that includes a component of controlled active flexion is suggested for injuries at the A3 and A4 levels. This radiographic stereophotogrammetric analysis method developed for tendon excursion and dehiscence is new and provides knowledge that cannot be obtained in any other way.

Adolescent↗

Calcific tendonitis of the subscapularis tendon causing subcoracoid stenosis and coracoid impingement.

Calcific tendonitis is a common disease of the shoulder which usually responds to conservative treatment. In cases unresponsive to conservative management, arthroscopic treatment is sometimes required. While there are several reports on calcifications within the supraspinatus tendon, documented cases involving the subscapularis tendon are rare. We present a case of a 47 year old farmer with recurrent anterior shoulder pain. An MRI revealed calcium deposits as well as a large subcoracoid cyst. Arthroscopic excision of the multiple calcific deposits left a large defect in the subscapularis tendon which was repaired back to the lesser tuberosity using arthroscopic techniques. A coracoplasty resulted in an increased coracohumeral space. The patient followed a conservative postop rehabilitation protocol and ultimately regained full strength and was pain free at the latest follow-up. We postulate two possible etiologies of subscapularis calcific tendonitis: either an idiopathic calcific tendonitis caused a secondary coracoid impingement or a primary subcoracoid stenosis resulted in an interstitial subscapularis tear which eventually resulted in calcium deposition. This report describes the clinical and technical details of arthroscopic excision of calcific deposits of the subscapularis tendon as well as arthroscopic repair of the resulting subscapularis defect.

Arthroscopy↗

Restoration of the injured flexor tendon surface: a possible role for endotenon cells. A morphological study of the rabbit tendon in vivo.

The ability of rabbit deep flexor tendons to restore the gliding surface and to heal, without the normal contribution of the superficial epitenon layer of the tendons, was studied by light and scanning electron microscopy. The epitenon layer was carefully removed from defined segments of the tendons. The remaining central tendon tissue was divided, sutured and placed in diffusion chambers subcutaneously in the back of the rabbits. After two weeks of culture, most of the sutured gaps were bridged and the tendons were encapsulated by flattened and spindle-shaped cells which covered a random network of thin collagen fibres. After five and 11 weeks, fibroblast-like cells in multiple layers formed a cobblestone-like surface. Thus, a tendon deprived of its epitenon layer still contains cells which can produce collagen, bridge the gap and restore the injured tendon surface.

Animals↗

In situ tibialis posterior to flexor digitorum longus tendon transfer for tibialis posterior tendon dysfunction: a simplified surgical approach with outcome of 11 patients.

Outcomes for 11 patients who underwent an in situ tibialis posterior tendon to flexor digitorum longus tendon side-to-side anastamosis as the sole procedure for stage 2 tibialis posterior tendon dysfunction were reviewed. The average follow-up was 34.4 months. Using the American Orthopedic Foot and Ankle Society hindfoot rating scale, a mean improvement of 39.3 points was achieved, with preoperative scores of 38.8 improving to 78.1 postoperatively. Good to excellent results were achieved in nine patients. The in situ side-to-side anastamosis is technically easier to perform, has less tissue trauma, and compares favorably with other soft-tissue procedures and reconstructions for stage 2 tibialis posterior tendon dysfunction. Performing this transfer alone, while leaving the flexor digitorum longus tendon intact, theoretically provides a stronger transfer as the length-tension relationship of the flexor digitorum longus tendon is maintained near its physiologic level. The procedure can consistently restore inversion ability to the rearfoot and stop the progression of tibialis posterior tendon dysfunction.

Adult↗

Flexor tendon repair using a stainless steel external splint. Biomechanical study on human cadaver flexor tendons.

A stainless steel external tendon splint was used in repair of cadaver tendons and compared with standard tendon repairs with suture. The splint was combined with a Kessler repair and tested against the Kessler, Becker, and Savage repairs in fresh human cadaver flexor digitorum profundus tendons. Biomechanical testing was done on a tensile testing machine, and load-displacement curves were generated. The repairs using the external tendon splint demonstrated a range of improvement of 32 to 146% in mean maximal tensile strength and a 20 to 185% improvement of mean ultimate tensile strength compared with all other repairs. The external tendon splint is relatively easy to apply to a tendon. The repair is strengthened and becomes capable of withstanding early active range of motion exercises. In vivo testing will be needed to assess the potential clinical usefulness of such a device.

Finger Injuries↗

The flexor digitorum profundus "demi-tendon"--a new technique for passage of the flexor profundus tendon through the A4 pulley.

The flexor digitorum profundus (FDP) tendon may retract after avulsion or division in Zone 1. When treatment has been delayed, the oedematous tendon can be too swollen to pass freely through the A4 pulley. We present a new technique for dealing with this situation which depends on the "double-barrelled" nature of the distal part of the FDP tendon. One half of the tendon is excised longitudinally and the remaining "demi-tendon" is passed through the intact A4 pulley to allow tendon repair or re-attachment. This technique has been used in six cases in which passage of the FDP tendon through the A4 pulley would otherwise have been impossible.

Adult↗

[Resection of the tendon of the peroneal brevis muscle in "clicking" peroneal tendons--a report of 3 cases].

INTRODUCTION: The following article deals with the problem of peroneal clicking. This means a clicking of the two peroneal tendons against each other. It has to be differentiated from peroneal tendon dislocation or subluxation. METHOD: In three patients, a peroneal click was found without symptoms of dislocation of the tendons over the fibula. In these cases the indication for resection of the peroneal brevis tendon was seen. RESULTS: Postoperatively no pain, swelling, and peroneal click were present. The partial loss of function of the peroneal brevis tendon seems to be negligible. CONCLUSION: In case of pain and swelling over the peroneal tendons, peroneal clicking should be included in a differential diagnosis. Resection of the peroneal brevis tendon is an effective treatment in these cases.

Adult↗

Free gracilis tendon graft in neglected tears of the achilles tendon.

OBJECTIVE: To report the results of a longitudinal study on reconstruction of neglected Achilles tendon rupture using a free autologous gracilis tendon graft. DESIGN: Cohort study. PARTICIPANTS: Twenty-one patients underwent surgery for a neglected rupture of the Achilles tendon occurring between 65 days and 9 months before the operation. METHODS: All participants were prospectively followed up for 2 years, and final review was performed at 28.4 +/- 3.5 months from the operation. Functional (anthropometric measurements, isometric strength, return to activities) and clinical assessment was performed. RESULTS: No patients experienced any problems in the wound used to harvest the tendon of gracilis. Five patients were managed conservatively following a superficial infection of the Achilles tendon surgical wound. No patients developed a deep vein thrombosis or sustained a rerupture. All patients were able to walk on tiptoes, and no patient used a heel lift or walked with a visible limp. The maximum calf circumference remained significantly decreased in the operated leg at final review. The operated limb was significantly less strong than the nonoperated one. CONCLUSIONS: The management of neglected tears of the Achilles tendon by free gracilis tendon grafting is safe but technically demanding. It affords good recovery, even in patients with a neglected rupture of a duration of 9 months. These patients should be warned that they are at risk for postoperative complications, and that their ankle plantar flexion strength can remain reduced.

Achilles Tendon↗

Reconstruction of chronic Achilles tendon defects with posterior tibial perforator flap and soleus tendon graft: clinical series.

BACKGROUND: Reconstruction of chronic composite defects of the Achilles region is difficult, and many techniques have been proposed, most of which are technically complex. A simple and effective technique has not yet been described. METHODS: Eight patients with chronic composite defects of the Achilles tendon underwent reconstruction using a local tendon graft from the soleus tendon and a posterior tibial perforator flap in a single stage. Follow-up was 9 to 50 months. RESULTS: All reconstructions were successful, without flap loss, infections, or reruptures of the tendon. Minor skin graft loss over the flap was a complication in three cases. Patient satisfaction was uniformly high. CONCLUSION: The posterior tibial perforator flap combined with a local tendon graft from the soleus tendon is an effective and technically simple solution for reconstruction of chronic infected defects of the Achilles tendon of moderate size.

Achilles Tendon↗

Results of primary tendon repair with closure of the tendon sheath.

This study reports the results of primary flexor tendon repair combined with closure of the tendon sheath in 31 Zone 2 injuries. In 3 digits, the profundus tendon alone was divided. In a further 7 digits, one tendon was completely divided and the other was incompletely divided. The remaining 21 digits involved complete division of both tendons. Assessment of the results according to the total active motion (TAM) system found 86% of the repairs in the excellent, good and fair categories. Two ruptures occurred (6%). A second assessment employed the criteria of Strickland, excluding the motion of the metacarpophalangeal joint. The results obtained following suture of both tendons were: excellent (39%); good (36%); fair (14%); poor (4%); and rupture (7%). These results lend support to the belief that closure of the tendon sheath decreases external adhesion formation and improves motion without increasing the risks of rupture.

Adult↗

Correlation of cartilage oligomeric matrix protein (COMP) levels in equine tendon with mechanical properties: a proposed role for COMP in determining function-specific mechanical characteristics of locomotor tendons.

Over-strain injury of the superficial digital flexor tendon (SDFT) is a common injury in the horse. Tendon appears to adapt to loads placed on it during development, but fatigue damage accumulates after skeletal maturity, which is inadequately repaired and predisposes to clinical tendinitis. In any population of horses, there is a wide variation in SDFT mechanical properties. A noncollagenous protein, cartilage oligomeric matrix protein (COMP), is particularly abundant during growth in the equine SDFT and has been proposed to have an organisational role in the formation of collagenous matrices. This study aimed to determine whether COMP levels were correlated to mechanical properties at skeletal maturity. Tendons from 2 groups of 12 horses were analysed: Group 1 horses with restricted age, 2 years +/- 2 months, showed a significant correlation between both ultimate tensile stress modulus of elasticity and stiffness and COMP, while Group 2 mature horses with varying age did not, because of age- and exercise-induced loss of COMP. These data supports the hypothesis that COMP is an important mediator in the growth of tendon. This data would suggest that the identification of low COMP levels in tendon during growth would indicate horses prone to tendon injury and methods of promoting COMP synthesis during growth would potentially improve tendon quality and reduce the risk of subsequent tendinitis.

Age Factors↗

Effects of patellar tendon width and preoperative quadriceps strength on strength return after anterior cruciate ligament reconstruction with ipsilateral bone-patellar tendon-bone autograft.

BACKGROUND: Strength return after anterior cruciate ligament reconstruction varies greatly. HYPOTHESIS: Patients with small patellar tendons and weak preoperative quadriceps muscle strength would not be able to regain full strength. STUDY DESIGN: Retrospective review of prospectively collected data. METHODS: Patellar tendon widths for 540 patients were measured intraoperatively and grouped according to size (small, 20-26 mm; medium, 27-30 mm; large, 31-36 mm). Strength measured preoperatively was determined by dividing the torque value of the injured leg by the torque value of the noninjured leg. Strength after surgery was determined by dividing the postoperative value in the anterior cruciate ligament-reconstructed leg by the preoperative value of the uninjured leg. RESULTS: At 1, 2, and 3 months after surgery, patients with large tendons had statistically significantly better strength than patients with small and medium tendons (P < .01), but this difference was not significant 2 years after operation. At all times after surgery, patients with preoperative strength >90% had statistically significantly better strength than patients with preoperative strength <75% (P < .01). At 3 months after surgery, patients with good preoperative strength and large tendons had a mean postoperative strength of 79% compared with 62% for patients who had poor preoperative strength and small tendons (P < .001). CONCLUSIONS: If patients undergoing anterior cruciate ligament reconstruction have a weak leg before surgery and small patellar tendons, their ability to regain full strength after surgery may be compromised, especially in the first year after surgery.

Adolescent↗

Strength analysis and comparison of the Teno Fix Tendon Repair System with the two-strand modified Kessler repair in the Achilles tendon.

BACKGROUND: Various options exist for repair of Achilles tendon ruptures, yet a method that consistently provides sufficient gap resistance to allow early mobilization remains elusive. This study compares the mechanical performance of a modified Kessler repair with that of the Teno Fix Tendon Repair System (Ortheon Medical, LLC) in matched pairs of cadaver Achilles tendons. METHODS: The two-strand modified Kessler repair was selected as the control construct on the basis of literature review and physician interviews which identified it among the many options as a popular method for repair of acutely ruptured Achilles tendons. Test specimens were harvested from matched pairs of cadaver ankles. The tendons were transected 3.5 cm proximal to the calcaneal insertion and repaired with either the two-strand modified Kessler suture construct or the Teno Fix Tendon Repair System. Assignment to the modified Kessler or Teno Fix group was done randomly for the first member of each pair. All test and control repairs were performed by the same author to reduce variability. Evaluation of the repairs consisted of tensile strength testing and measurement of the gap formation and peak stresses. RESULTS: Gap and peak stress for the two-strand modified Kessler repair were 0.30 +/- 0.15 N/mm2 and 1.03 +/- 0.51 N/mm2, respectively. For the Teno Fix repairs the mean gap and peak stress values were 0.80 +/- 0.46 N/mm2 and 1.19 +/- 0.12 N/mm2, respectively. The mean gap formation stress was significantly higher in the Teno Fix repairs than in the control repairs (p < .0005). There was no significant difference in peak strength between the repairs (p < .10). CONCLUSIONS: The Teno Fix repair was superior to the modified Kessler repair. In the Teno Fix repairs, the gap formation stress was 67% of the peak tensile stress. In comparison, in the modified Kessler repairs, the gap formation stress was 29% of the peak stress. This can be correlated to the elastic property of the modified Kessler suture and the initial tightening of the suture around the tendon fibers. The Teno Fix system is nonelastic and is fully tensioned during installation. This lends to a more gap resistant repair.

Achilles Tendon↗