H E Cabaud — Page 2 | PubMed Health

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A partially biodegradable material device for repair and reconstruction of injured tendons. Experimental studies.

We assessed the applicability of a partially biodegradable synthetic material composed of polyglycolic acid (PGA) and dacron to repair or replace severely injured tendons. Adult rabbits underwent complete laceration and repair of one Achilles tendon. Group 1 (N = 8) had end to end tenorrhaphy with size 0 braided polyester suture, and Group 2 (N = 16) tendons were similarly repaired with the bicomposite designed PGA-dacron device. Group 3 (N = 16) received laceration and removal of 1 cm of tissue, and the defect was bridged with the same PGA-dacron material. No postoperative immobilization was applied. Evaluation, consisting of biomechanical testing or histologic inspection, was done at 4 and 8 weeks after tenorrhaphy. All tendons healed, and at 8 weeks the mean maximum load at failure of the repaired tendons was 32.2 +/- 3.4 kgf, 40.3 +/- 2.4 kgf, and 31.8 +/- 3.2kgf for Groups 1, 2, and 3, respectively. Values between groups were not significantly different, but all were significantly less (P less than or equal to 0.05) than the strength of the unoperated control tendons (55.8 +/- 7.2 kgf). The most noteworthy finding was the lengthening of the repaired tendons, due to scar elongation at the tenorrhaphy site, that occurred during healing as determined by a landmark placed a fixed distance proximal to the repair site. Group 1 tendons lengthened 22 mm, while Group 2 and 3 tendons increased by 12.5 mm. Histologically, fibrous tissue ingrowth into the residual dacron scaffold occurred, but it was inconsistent and inadequate in quality and quantity to be satisfactory as neotendon. The fibrous tissue did not mature or align in response to load. We concluded that the PGA-dacron material had adequate strength and physical properties to use both for primary tenorrhaphy and to bridge the tendon defect. However, in our experience this material lacks any significant advantage over other materials available or known to be under evaluation to support neotendon formation when an actual soft tissue defect exists.

Achilles Tendon↗

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Biomechanics of the anterior cruciate ligament.

The principal role of the anterior cruciate ligament (ACL) is to resist anterior displacement of the tibia on the femur. The ACL also has a major role in resisting internal rotation. The posterior fibers are longest, or most tense, in extension, and are therefore the major resistance to hyperextension and are more susceptible to injury in extension. The anterior fibers are longest, or most tense, in flexion and therefore are not susceptible to injuries with the knee flexed. The ACL is strong and stiff, yet because of its unique structure, it is precariously susceptible to injury.

Biomechanical Phenomena↗

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The patellar compression syndrome: surgical treatment by lateral retinacular release.

Patellar compression syndrome may be a manifestation of contraction of the lateral retinacular structures which consists largely of the lateral patellofemoral ligament producing a tethering action on the patella. This may produce parapatellar pain, particularly in activities requiring repetitive knee flexion. Minor patellofemoral incongruencies with pain, grating, and functional limitation may be found on examination but the patient does not demonstrate the problems of instability of marked congenital abnormalities often seen with other patellar problems. Forty patients underwent a simple release of the lateral retinaculum to decompress the patella in the patellofemoral groove. Follow-up was obtained in 31 patients at an average of 18.3 months after surgery. Twenty-four knees which had severe preoperative pain were converted to 6 with no pain, 4 with mild pain, 11 with moderate pain and 3 whose pain remained unchanged after surgery. Twenty knees with moderate preoperative pain were changed to 4 with no pain, 11 with mild pain and 4 whose pain remained unchanged. Thirty-seven of the 45 knees had lessening of the pain after the operation and 10 patients returned to unrestricted atheletic activities.

Adolescent↗