Regeneration of resected calcaneal tendon of the rabbit

Presurgical Perspective and Postsurgical Evaluation of Non-Achilles Tendons of the Ankle and Retinaculum

The vast majority of non-Achilles ankle tendinopathies are related to overuse. This article discusses the clinical aspect, imaging appearance, and management of tendinopathies of the lateral, medial, and the anterior compartments with a focus on presurgical perspective and postsurgical evaluation.

Functional management of Achilles tendon rupture: A viable option for non-operative management

BACKGROUND

Functional management of the ruptured Achilles tendon can be effective using orthoses like the removable walker boot (Foam Walker Boot, Air Cast UK Limited, Lincolnshire, United Kingdom). We conducted this study to look at the outcome of our protocol using this orthosis.

MATERIALS AND METHODS

We retrospectively reviewed 107 non-operatively managed Achilles tendon ruptures over the last 5 years. Case notes were analyzed for demographics and immediate outcomes. Long term outcomes were assessed by a postal questionnaire using the Achilles Tendon Total Rupture Score (ATRS).

RESULTS

Of the 107 tendons (male:female=71:36, mean age=50 years), 105 tendons (98%) healed with an average discharge time of 22 weeks. Six patients reported major complications and 6 reported minor complications. We received 56 questionnaires with a mean ATRS score of 21. Seventy-seven percent returned to pre-injury level of activity.

CONCLUSION

Functional management of Achilles tendon rupture, under appropriate supervision, provides a viable option for non-operative management.

Ankle morbidity after autogenous Achilles tendon harvesting for anterior cruciate ligament reconstruction

Although several alternative autografts with reduced morbidity of harvest site have been introduced, no donor site is free of morbidity concerns. The authors report on ankle status after autogenous Achilles tendon harvesting with a minimum 10-year follow-up. From October 1994 to October 1996, a consecutive series of 47 ankles underwent harvesting of the medial third or half of the ipsilateral autogenous Achilles tendon for primary anterior cruciate ligament reconstruction. Donor site statuses were evaluated using a modified Thermann's scale. Postoperative isokinetic muscle strength testing was performed, and magnetic resonance images of donor sites were available for selected patients. Thirty-three ankles in the 32 patients were followed for more than 10 years. There were 27 men (84%) and 5 women (16%) with a mean age of 31 years (range 16-52 years) at the time of surgery. The mean duration of follow-up was 12 years and 1 month (range 10 years and 5 months to 13 years and 4 months). Mean postoperative modified Thermann's scale score was 87 (range 45-95; SD 14.3). Twenty-five (76%) ankles achieved very good or good results. A slight decrease in calf circumference <1 cm was seen in the ten ankles, 1-2 cm in the four ankles. Nine ankles were mildly hypersensitive to meteorological changes. Peak torque of ankle plantar flexion was slightly lower on the index limb at both velocities in nine selected patients who carried out performance tests. However, there were no significant differences (5.2% at 30 degrees /s and 2.7% at 120 degrees /s, P = n.s. and P = n.s.). Of the 12 available follow-up magnetic resonance images, the average cross-sectional area of the remaining tendon was 82.01 mm(2) (range 69.05-107.35; SD 10.3), and their average thickness was 7.4 mm (range 6-10.35; SD 1.1). After a minimum 10-year follow-up, the harvesting of autogenous Achilles tendons was not found to significantly jeopardize ankle status. However, it also could not be independent of donor morbidity as an alternative. The level of evidence was retrospective level IV, as a therapeutic study.

Management of chronic ruptures of the Achilles tendon

Chronic ruptures of Achilles tendons are those that present four to six weeks after the original injury. They have become more common as acute Achilles tendon injuries have become more frequent, and they are associated with considerable functional morbidity. Most surgeons agree that chronic ruptures should be managed operatively. Diagnosis is based predominantly on history and clinical examination. Real-time, high-resolution ultrasound and magnetic resonance imaging are helpful in preoperative planning or as a diagnostic aid. Local tissue, local tendons, and allografts can be used to reconstruct the tendon, and end-to-end repair is possible if the gap is <2.5 cm. Compared with acute injuries, chronic injuries are associated with a higher rate of postoperative infection and more prolonged recovery.

Chronic rupture of tendo Achillis

The Achilles tendon is the most commonly ruptured tendon in the human body. About 20% of complete ruptures of the Achilles tendon are diagnosed late. The management of chronic ruptures of tendo Achillis is usually different from that of acute rupture, as the tendon ends normally will have retracted. As clinical diagnosis of chronic ruptures can be problematic, imaging can be useful. Most investigators counsel operative management, and the possibility of undertaking a tendon transfer should be kept in mind. Local tendons, such as the flexor digitorum longus, the flexor hallucis longus, and the tendon of peroneus brevis, can be used, and some investigators have reported the use of a free gracilis tendon graft. Allografts and synthetic grafts are also employed. There are no comparative studies and no randomized controlled trials to guide clinicians toward an evidence-based approach to management.

Neglected ruptures of the Achilles tendon

Neglected Achilles tendon ruptures, although uncommon, are debilitating injuries. The optimal management is surgical. Many different techniques can be used to repair or reconstruct the rupture, including tendo-Achilles advancement or flap reconstruction; local tendon transfer; and autologous, autograft, or synthetic implantation. Comparison of different techniques is difficult.

Evaluation of collagen fiber maturation and ordering in regenerating tendons employing H-1 double quantum filtered NMR spectroscopy

It is difficult to monitor the chronic stage of the healing process of ruptured tendons employing the present diagnostic modes. However, the results of this study have shown that 1H double quantum filtered (DQF) NMR spectroscopy is sensitive to the later stages of the healing process. Regenerated tendons of rabbits were dissected and measured at the end of the acute phase (three weeks), the subacute phase (nine weeks), and the chronic phase (13 and 18 weeks after tenotomy). Four parameters were determined by 1H DQF NMR spectroscopy: (a) the maximum signal intensity (h(max)) relative to the single quantum spectrum, (b) the creation time of the maximum signal intensity (tau(max)), (c) the decay time from the maximum signal intensity to a value half of that intensity (tau(1/2)) and (d) the residual dipolar splitting of water (delta), representing the order of the collagen fibers. The values of h(max), tau(max), tau(1/2), and delta of the intact Achilles tendons were 11.3+/-1.0%, 0.48+/-0.03 ms, 0.67+/-0.04 ms and 732+/-62 Hz (mean +/- SEM, n=6), respectively. In the regenerating tendon, h(max) increased from 0.41+/-0.12% at three weeks to 7.07+/-0.77% at 18 weeks, tau(max) decreased from 1.88+/-0.31 ms at three weeks to 0.72+/-0.04 ms at 18 weeks, tau(1/2) decreased from 11.6+/-1.8 ms at 3 weeks to 1.48+/-0.16 ms at 18 weeks, and delta increased from 129+/-8 Hz at three weeks to 414+/-29 Hz at 18 weeks. We have concluded that reordering of collagen fibers proceeds continuously even in the chronic stage of healing. Thus, the 1H DQF NMR spectroscopy is a useful non-invasive technique to evaluate the reconstruction and the order of collagen fibers in regenerating tendon. It is also suggested that tau(1/2) and h(max) are most useful for in vivo DQF NMR spectroscopy and imaging, respectively, in combination with tau(max).

Characteristics of proton NMR T(2) relaxation of water in the normal and regenerating tendon

The molecular behavior of water in normal and regenerating tendons was analyzed using the transverse relaxation time (T(2)) measured by spin-echo proton nuclear magnetic resonance ((1)H-NMR) spectroscopy at 2.34 T (25 degrees C). A section of the Achilles tendon was dissected from an anesthetized Japanese white rabbit, and its longitudinal axis was oriented at 0, 35, 54.7, 75, and 90 degrees to the static magnetic field. In the normal tendon, the T(2) relaxation of water presented biexponential relaxation and anisotropy in both the long T(2) (5.41 to 6.21 ms) and short T(2) (0.41 to 1.43 ms) components, in which the greatest values were obtained at 54.7 degrees. However, the range of the anisotropy was much narrower than we expected from the (1)H dipolar interaction of water bound to the collagen fibers in the tendon. The apparent fractions of water proton density also varied with orientation: the fraction of the longer T(2) components was at its maximum at 54.7 degrees. These results suggest that a simple two-compartment model could not be applicable to orientational dependency of the T(2) value of the tendon, and the well ordered water in the short T(2) relaxation component may show an elongated T(2) relaxation time that falls in the range of the long T(2) relaxation component at 54.7 degrees. This hypothesis can explain both the narrower range of the T(2) relaxation time and the orientational dependency on the apparent fraction of (1)H density. Regenerating processes of the Achilles tendon were followed for 18 weeks by analyzing the T(2) relaxation time. There is only a long T(2) relaxation time component (21.8 to 28.0 ms) up to 3 weeks after transection. Biexponential relaxation is revealed at 6 weeks and thereafter, whereby (i) the T(2) relaxation times become shorter, (ii) there is anisotropy in the short and long T(2) values, and (iii) the orientational dependency of the apparent fraction of water proton density becomes evident with maturation of the regenerating tendon. From these results, the (1)H T(2) relaxation time of water might be used to monitor the healing process of collagen structures of the tendon non-invasively.

Neglected rupture of the Achilles tendon

Delayed treatment of a rupture of the Achilles tendon is a challenge. Operative treatment is generally recommended, with a variety of techniques being described to appose the tendinous ends and augment the repair.

Collagen fibril diameters in the healing adult rabbit medial collateral ligament

This study was carried out to test the hypothesis that improvements in ligament scar mechanical behavior during healing may be related, in part, to increases in collagen fibril diameters. Forty-eight adult female New Zealand White rabbits had standardized midsubstance gap injuries created in their right medial collateral ligaments (MCLs) and were allowed normal cage activity until sacrifice in groups of 12 at 3, 6, 14 or 40 weeks post-injury. Eight animals in each group had both MCLs tested biomechanically while 4 animals had transmission EM investigation of midsubstance collagen fibril diameters by a standardized protocol. Results of mechanical tests showed a three- to fourfold increase in scar strength and stiffness over the intervals of healing studied while there was no change in collagen mean fibril minimum diameters. These results demonstrate no correlation between material or structural properties of scar and collagen fibril diameters in this model of healing and suggest that other mechanisms for scar mechanical improvement under these conditions must be investigated.

Connective tissue plasticity: ultrastructural, biomechanical, and morphometric effects of physical factors on intact and regenerating tendons

Supported in part by a grant from the Foundation for Physical Therapy and a merit grant from Veterans Affairs Rehabilitation Research and Development Program. Proceedings from the 1991 Eugene Michels Research Forum, Combined Sections Meeting, Orlando, FL, January-February, 1991. Special thanks to A. Joseph Threlkeld, University of Kentucky Medical Center, Lexington, KY, for helping acquire the presentation material for publication. J Orthop Sports Phys Ther 1991;14(5):198-212.

Rupture of the Achilles tendon treated by a simple operative procedure

A subcutaneous suture technique for repair of closed rupture of the Achilles tendon first reported in 1977 is described again. The use of the technique in Aberdeen is compared with cases treated in plaster during the same 2-year-period. Although the total in the series is only 35, the results appear to indicate that the subcutaneous suture technique improves the power of plantar flexion without significant post-operative complications.

Surgical repair of the ruptured Achilles tendon. Analysis of 40 patients treated by the same surgeon

Forty patients with acute ruptures of the Achilles tendon were treated surgically by the same physician (T.B.Q.) during a period of 1947 to 1971. The average followup was 19 years. Ninety percent of the patients were men (average age 37.5 years) who were engaged in recreational sport activities. The majority denied a physical conditioning program. The acute ruptures were treated by a surgical procedure which consisted of a 15-cm incision on the medial aspect of the tendon with either the plantaris muscle being woven through the Achilles tendon in a clockwise fashion or a pull-out wire, supplemented with silk mattress sutures, being used to repair the ruptured tendon. The wound was closed and the patient's leg was immobilized. The wire was removed at 6 weeks. The rehabilitation plan consisted of ambulation with a heel lift and elastic stocking (the height of the lift was gradually reduced) and toe exercises. The patients began walking downstairs backwards at 3 months and continued exercises until full range of motion was attained. Subjectively, the results were excellent as graded by the patients. Objectively, there were some minor deficits but they did not impede the overall function. On a scale of 1 (poor) to 4 (excellent), the clinical results were rated excellent (42%), good (36%), fair (15%), and poor (6%). This review has supported our contention that a positive Thompson test is a reliable indicator for a rupture of the Achilles tendon and that surgical treatment of complete ruptures is a successful mode by the procedure described followed by our rehabilitation program.

Regeneration of rabbit calcaneal tendon maturation of collagen and elastic fibers following partial tenotomy

Regenerated tendon tissue replacing partial-thickness defects produced in rabbit calcaneal tendons was seen to undergo almost complete maturation between three and sixteen weeks after surgery. At this stage, most collagen fibers had large diameters as in normal tendon, and the majority of elastic fibers were mature. This findings, along with those of a previous study on completely severed and unsutured tendons, indicate that mechanical stress plays a primary role in maturation of regenerating tendon. This emphasizes the importance of close approximation of tendon ends in the management of tendon ruptures and lacerations. This is possibly by surgical repair.

Methods and rationale for closed treatment of Achilles tendon ruptures

A method of closed treatment of Achilles tendon ruptures by casting, utilizing a long leg cast for 6 weeks and a short leg cast for 4 additional weeks, is presented. An experimental model using rabbits supports the clinical contention that closed approximation and immobilization of Achilles tendons allows tendon healing to progress, at least in the early stages. Observations made on the tendon sheath during early healing attribute a very positive role to it in providing needed blood supply to the tendon. The importance of maintaining a smooth gliding surface as well suggests that the tendon sheath should not be violated by surgical repair on the Achilles tendon.