From August 1989 to January 1995 we performed multiple percutaneous longitudinal tenotomies under local anesthetic on 52 middle- and long-distance runners with unilateral Achilles tendinitis or peritendinitis that had failed conservative treatment. Forty-eight patients were reviewed at an average of 22.1 months (SD, 6.5) after surgery. Results were rated as excellent in 25 patients, good in 12, fair in 7, and poor in 4. Four patients developed subcutaneous hematomas. One patient developed a superficial infection at one of the incision sites, which was managed by oral antibiotics with full recovery. Three patients complained of over-sensitivity to the incisions; this was resolved by rubbing hand cream over the incisions several times a day. One patient developed hypertrophic painful scars on three of the five incisions, but corticosteroid injections yielded good functional and cosmetic results. Isometric strength and endurance of the gastrocsoleus complex was measured just before the procedure, and at 6 weeks and 6 months later. Both were within 10% of the normal contralateral limb by the 6th postoperative month. Percutaneous longitudinal tenotomy is simple, can be performed on an outpatient basis, requires minimal follow-up care, and, in our experience, has produced no significant complications. We use this procedure as the operative treatment of choice for cases of chronic tendinitis that have failed conservative treatment.

No abstract

Thirty-eight athletes with unilateral patellar tendinopathy (17 with a tendinopathy of the main body of the tendon, and 21 with an insertional tendinopathy) underwent ultrasound-guided multiple percutaneous longitudinal tenotomy under local anaesthetic infiltration after failure of conservative management. Thirty-four patients were reviewed at least 24 months after the operation. Sixteen patients were rated excellent, nine good, eight fair, and five poor. Nine of the 13 patients with a fair or poor result had an insertional tendinopathy, and eight of them underwent a formal exploration of the patellar tendon. Before the operation, there were some areas of altered echogenicity at and around the site of involvement. These were still visible 6 wk after surgery in 70% of the patients. At the latest follow-up, in the patients with an excellent or good result, the tendon was generally isoechogenic but slightly thicker (P = 0.06) than the normal contralateral. In the patients with a fair or poor result, the tendon was significantly thicker than the contralateral (P = 0.03), and showed some areas of mixed echogenicity. In the patients in whom the procedure was successful, the thicker operated tendon did not interfere with physical training. Bilateral isokinetic peak torque (Nm), average work (Joules), and average power (Watts) were tested at 90 degrees x s(-1). Immediately before the operation, there was no significant difference in peak torque, but total work and average power were significantly lower in the limb to be operated (0.01 < P < 0.05). By the end of the study, although peak torque was, on average, within 7% of the unoperated limb, total work and average power were still significantly lower than in the unoperated limb (0.01 < P < 0.04). Percutaneous longitudinal internal tenotomy is simple, can be performed on an outpatient basis, requires minimal follow-up care, does not hinder further surgery should it be unsuccessful, and, in our experience, has produced no significant complications. In our hands, it has become the first line operative intervention in the treatment of chronic patellar tendinopathy after failure of conservative management. However, patients should be advised that, if they suffer from an tendinopathy at the attachment of the patellar tendon at the lower pole of the patella, a formal surgical exploration with stripping of the paratenon is preferable.

Distributing the train traction power over cars of modern High Speed trains, which represent one of the main loads of European electrical power systems, is considered and its effects on dependability are analyzed with reference to the daily duty-cycle. Two different possible solutions for the traction systems, the former based on four converters and eight motors, the latter on six converters and 12 motors are compared in terms of service dependability, immobilizing risks and expected failure entity per day. Simplified Markov models are obtained by means of a proper selection of the most likely states. The models are also extended to represent the case of log-normal distributions for repair times, and are solved separately for mission and idle times, by tuning the transition rates with the different duty-cycle stages. Numerical applications give the opportunity of verifying the proposed approach suitability and of making quantitative comparisons between the two different considered trains.