Biomechanical evaluation of 2 techniques for ulnar collateral ligament reconstruction of the elbow.

Background: Elbow medial ulnar collateral ligament tears often result in pain and instability that may be career threatening in overhead-throwing athletes. Surgical reconstruction is frequently chosen to treat this injury. Ulnar collateral ligament reconstruction as described by Jobe is the most commonly used technique.

Isolated fibrillar damage in tendons stimulates local collagenase mRNA expression and protein synthesis.

The etiology of repetitive stress injuries in tendons has not been clearly identified. While minor trauma has been implicated as an inciting factor, the precise magnitude and structural level of tissue injury that initiates this degenerative cascade has not been determined. The purpose of this study was to determine if isolated tendon fibril damage could initiate an upregulation of interstitial collagenase (MMP13) mRNA and protein in tendon cells associated with the injured fibril(s).

Tendon injury response: assessment of biomechanical properties, tissue morphology and viability following flexor digitorum profundus tendon transection.

Insertion site injuries of the flexor digitorum profundus (FDP) tendon often present for delayed treatment. Apart from gross observations made at the time of surgery, the changes that occur in the flexor tendon stump during the interval from injury to repair are unknown. These changes may include tendon softening and loss of viability, which may contribute to the poor outcomes observed clinically and experimentally.

The insertion site of the canine flexor digitorum profundus tendon heals slowly following injury and suture repair.

Treatment of injuries of the flexor digitorum profundus (FDP) tendon insertion site has changed little during the past 50 years, in part because there are no reports describing flexor tendon insertion site healing. Our objective was to assess the effects of repair technique and post-operative time on tendon-bone healing using a canine model of injury and repair. We transected 48 FDP tendons from 24 dogs at their insertions and repaired them using either a four- or eight-strand suture technique.

The rigidity of repaired flexor tendons increases following ex vivo cyclic loading.

Transected flexor tendons are typically treated by suture repair followed by rehabilitation that generates repetitive tendon loading. Recent results in an in vivo canine model indicate that during the first 10 days after injury and repair, there is an increase in the rigidity of the tendon repair site. Our objective was to determine whether or not ex vivo cyclic loading of repaired flexor tendons causes a similar increase in repair-site rigidity.

A method for delivering variable impact stresses to the articular cartilage of rabbit knees.

Objective: To develop a method by which a single impact force of controlled magnitude and rate could be applied uniformly to an area on the posterior aspect of the medial femoral condyle of adult rabbits.

Design: An in-vivo animal model using a pendulum device, designed and manufactured to supply the kinetic energy necessary to apply different impact loads to the posterior aspect of the medial femoral condyle of a rabbit.

Setting: Biomechanical laboratory, University Medical Center.