Os trigonum syndrome: a clinical entity in ballet dancers.

Thirteen Swedish National classic ballet dancers were surgically treated for an "os trigonum syndrome."Their main symptom was an impingement pain in the hind foot while actively plantarflexing the ankle during ballet dancing. The surgical procedure included excision of an os trigonum or a prominent lateral posterior process of the talus, together with division of the flexor hallucis tendon sheath if it was thickened. This procedure was safe and resulted in return of the dancers to the same level of ballet dancing within 5 to 10 weeks.

The influence of growth hormone on the reversibility of articular cartilage degeneration in rabbits.

Growth hormone has chondrogenic affects on normal as well as on damaged articular cartilage. In this study, the influence of growth hormone is investigated on early degenerative changes in the articular cartilage in 72 New Zealand white rabbits. Cartilage lesions were created in femoral condyles using an immobilization model. Cartilage damage was assessed using biochemical, histologic, and biomechanical criteria. Growth hormone had no influence on prevention of immobilization abnormalities but had a significant affect on healing of established lesions.

A biomechanical study of tendon adhesion reduction using a biodegradable barrier in a rabbit model.

Adhesion formation associated with tendon surgery is a widespread problem in which a healing tendon becomes adherent via scar tissue to surrounding structures such as bone, muscle, skin, tendon sheath, or other tendons. A model is described in which adhesions were generated reproducibly between the plantaris and Achilles tendons of the rabbit using a partial tenotomy, a Bunnel suture, and immobilization. Using this model, the effect of an absorbable barrier, INTERCEED (TC7), on adhesion formation was investigated. This material, which is a fabric comprised of oxidized regenerated cellulose, was found to diminish significantly the extent and severity of intertendinous adhesions, assessed both mechanically and histologically. No evidence of a foreign body reaction was observed.

The influence of indomethacin on biomechanical and biochemical properties of the plantaris longus tendon in the rabbit.

It has previously been reported that indomethacin inhibits fracture healing and heterotopic bone formation. Stimulated by these reports, we undertook the present investigation to study the influence of indomethacin on biomechanical and biochemical properties of the plantaris longus tendon in the rabbit. Sixty-eight New Zealand White rabbits were used for the experiment. Half of them were treated with indomethacin, 10 mg/kg orally a day, and the other half with placebo. After 4, 8, and 16 weeks of treatment biomechanical and biochemical variables were determined and compared between the two groups. After 16 weeks there was a significant increase in tensile strength in the group treated with indomethacin. There was no certain concomitant change in the total collagen content, the amounts of soluble and insoluble collagen, or the water content. Further investigations concerning the influence of indomethacin on tendon healing are indicated.

The influence of indomethacin on collagen synthesis during tendon healing in the rabbit.

The influence of indomethacin on collagen synthesis in intact and healing plantaris longus tendons in the rabbit was investigated. Forty-four male New Zealand White rabbits were subjected to a standardized trauma (tenetomy + repair) on the left hindlimb. Half of the animals were subsequently treated with indomethacin, 10 mg/kg per day orally, and the other half with placebo. After 2 and 4 weeks the rabbits were injected intravenously with 3H-proline and killed 18 h later. Indomethacin affected the collagen metabolism differently depending on whether the tendons were involved in wound healing or not. In intact tendons the drug caused a small general inhibition of collagen synthesis. In the healing tendon there was a shift towards the synthesis of more insoluble collagen with little effect on the total synthesis. After 4 weeks there was also a slight but significant decrease in the amount of hydroxyproline in the most soluble collagen fraction from the tenotomized, indomethacin treated tendons.

Biomechanical and biochemical studies of tendon healing after conservative and surgical treatment.

Based on clinical studies, it has been proposed that conservative treatment of Achilles tendon ruptures is feasible. However, no biomechanical or biochemical confirmation of this proposal has been presented. In the present investigation the biomechanical and biochemical properties of tendons treated surgically and conservatively after transverse tenotomy were studied. Sixty-eight New Zealand White rabbits were used. A transverse tenotomy of the plantaris longus tendon of the left hind leg was performed. In half of the animals the tenotomy was repaired with a criss-cross silk suture and the limb was immobilized; the other half were treated with immobilization alone. The immobilization was maintained for 4 weeks with a long-leg plastic splint in both groups. After 4, 8, and 16 weeks the tendons were examined regarding biomechanical and biochemical parameters. There were no detectable differences in biomechanical parameters or in tendon elongation between the groups, nor was there any difference in the total hydroxyproline content, the amount of mature and of immature collagen, or the water content. The present findings are compatible with previous favorable reports on conservative treatment of Achilles tendon ruptures and thus suggest interesting clinical possibilities.

The influence of indomethacin on tendon healing. A biomechanical and biochemical study.

The influence of indomethacin on the biomechanical and biochemical properties of tendons during their healing was investigated. In 68 New Zealand White rabbits a transverse tenotomy followed by repair with a criss-cross suture was performed in the plantaris longus tendon of the left hind limb. The leg was immobilized for 4 weeks postoperatively in a long-leg plastic splint. Half of the animals were treated with indomethacin, 10 mg/kg/day orally, and the other half with placebo. After 4, 8, and 16 weeks of treatment the animals were killed and biomechanical and biochemical parameters were measured. After 16 weeks there was a significant increase in tensile strength in the indomethacin group. There were only small biochemical differences between the groups. However, there was a slight but significant decrease in the amount of soluble collagen in the indomethacin group. This may indicate a higher degree of cross-linkage following indomethacin treatment, which might explain the increased tensile strength.

A model for computer-aided analysis of biomechanical properties of the plantaris longus tendon in the rabbit.

Based on the present rapid development of user-friendly computer programs for non-linear curve fitting, the function P = a1 epsilon + a2 epsilon 3 (P = load, epsilon = strain, a1 = linear parameter, a2 = cubic parameter) for biomechanical analysis of the plantaris longus tendon in the rabbit is presented. A total of 188 plantaris longus tendons with different biomechanical properties (Plin ranging from 8.73-306.2 N) achieved by different treatments were used. With a simple load-strain sequence using a constant strain rate, load strain curves were obtained. The function was fitted to these curves up to a strain of 7.5%. The mean value for fraction of explained variance (FEV) was 0.996 (S.D. 0.002) indicating a very good fit and a high flexibility. Biomechanical and statistical analyses may be performed using only the two parameters a1 and a2 which give great data reduction and a considerable simplification of the statistical analysis.

Elongation of the plantaris longus tendon after surgical repair in the rabbit.

The purpose of this study was to investigate the elongation of the plantaris longus tendon in the rabbit after surgical repair. In 24 New Zealand white rabbits tenotomy of the plantaris longus tendon in the left hindlimb was performed. Surgical repair was undertaken with a criss-cross suture. The leg was immobilized in a long leg splint of Hexilite. The elongation of the tendon was measured by a photographic technique after preparation of the tendon. The elongation gradually increased during the observation time (r 0.03). No biphasic separation was found as indicated by other authors. For the clinical application of these findings further investigations are needed.