A prospective evaluation of untreated acute grade III acromioclavicular separations

We prospectively studied the natural history of untreated acute grade III acromioclavicular separations. Twenty-five patients were treated nonoperatively with a sling for comfort through progressive early range of motion as tolerated. Ten additional uninjured subjects underwent strength testing to evaluate the difference between the dominant and nondominant sides so that patient data could be standardized. The patients were examined at intervals of 6, 12, 24, 36, and 52 weeks after injury, at which time they completed a subjective questionnaire and underwent isometric dynamometer testing as well as military press and bench press strength testing. One patient underwent a surgical procedure at 2 weeks after injury because of cosmetic concerns. Twenty of the 25 patients completed the 1-year evaluation and strength-testing protocol. Subjectively, 4 of the 20 patients (20%) thought that their long-term outcome was suboptimal, although for 3 of them it was not enough to warrant surgery. Objective examination and strength testing of the 20 patients revealed no limitation of shoulder motion in the injured extremity and no difference between sides in rotational shoulder muscle strength. The bench press was the only strength test that showed a significant short-term difference, with the injured extremity being an average of 17% weaker. This study documents the natural history of patients with an untreated acute grade III acromioclavicular separation and provides a reference with which to judge all other proposed methods of treatment.

The effects of extended play on professional baseball pitchers

The purpose of this study was to investigate kinematic and kinetic changes as a result of extended play in baseball pitching. Seven major league baseball pitchers were videotaped with high-speed (120 Hz) cameras during multiple innings of the same game. For each athlete, two fastballs (one thrown during the initial inning of play and one from the final inning) were chosen for analysis. Twenty-one physical landmarks were manually digitized from the video data. Kinematic and kinetic parameters were subsequently calculated relative to four phases of the pitching motion: windup, cocking, acceleration, and follow-through. Paired t-tests revealed that seven parameters changed significantly between early and late innings. These included decreases in maximum external rotation of the shoulder, knee angle at ball release, ball velocity, maximum distraction force at both the shoulder and elbow, and horizontal adduction torque at both release and its maximum value. Ultimately, a decline in performance was evident by a 2 m/s (5 mph) drop in ball speed. It is unclear whether the kinematic and kinetic changes occurred because of fatigue or if protective mechanisms were adopted.

Comparison of tunnel suture and suture anchor methods as a function of time in a sheep model

There is little quantitative information available on the required healing time after a rotator cuff surgery. This study evaluated two surgical procedures by comparing the healing strength as a function of time of the tendon in a bone trough using a sheep model. The two surgical procedures compared were bioabsorbable suture anchors and bone tunnel suture technique. The infraspinatus tendon was split in half and procedure (suture anchor/tunnel suture) locations were randomly allocated to the proximal or distal half of the tendon at the healing time points of 0, 3, 6, 9, and 12 weeks with n = 6 at t = 0 and n = 8 in all other groups. At each time point, the surgical (right) and normal (left) shoulders were harvested and stored in a -30 degrees C freezer until testing. Biomechanical testing was performed using a MTS 809 Axial/Torsional Servohydraulic System. Special cryo-grips designed and built to test the infraspinatus tendon-bone interface in anatomical alignment were used. All samples were preloaded with 5 Newtons, and then force was measured during a crosshead displacement of 50 cm/min until failure. Force and displacement data were recorded to calculate load to failure and stiffness of the bone-tendon construct. There was only significant difference (95% CI) in mean tensile force at week 0, with the bone tunnel suture technique tensile force greater than the suture anchor method tensile force (p = 0.0261). There was no significant difference between stiffness means at any of the survival times.

The effect of immobilization on rotator cuff healing using modified Mason-Allen stitches: a biomechanical study in sheep

Long-term biomechanical integrity of the surgical site is crucial to the outcome of rotator cuff repair. Usually after rotator-cuff surgery, the arm is immobilized for 6-12 weeks to minimize disruption at the healing site. Unfortunately, currently there is very little clinical data on the effects of immobilization after rotator cuff surgery. This study analyzed the effect of immobilization on rotator cuff healing by comparing the healing strength of the tendon in a bone trough using a sheep model. In sixteen (16) female adult sheep, the right infraspinatus tendons were reattached into a bone trough using a modified Mason-Allen suture pattern. After surgery, each sheep was randomly assigned into either an immobilized or non-immobilized treatment group. The immobilized group was fitted with a softball taped under the foot to restrict limb movement for 6 weeks. The non-immobilized treatment group was allowed to fully bear weight on the treated shoulder. At 26 weeks, the animals were sacrificed and the surgical shoulders were harvested and stored in a -30 degrees C freezer. Biomechanical testing was performed using a MTS 809 Axial/Torsional Servohydraulic System. Special cryo-grips were used to test the infraspinatus tendon-bone interface in anatomical alignment. All samples were preloaded with 10 +/- 5 N, and then force was measured during a crosshead displacement of 500 mm/min until failure. Force and displacement were acquired at 100 Hz and used to calculate load-to-failure and stiffness of the bone-tendon interface. The load-to-failure (N) and stiffness (N/cm) were determined for both treatment groups. For the non-immobilized group, the loads to failure and stiffness means were 2571.95 +/- 329.9 N and 2319.09 +/- 457.72 N/cm. The immobilized group means were 2954.42 +/- 473.52 N (load-to-failure) and 2579.13 +/- 383.51 N/cm (stiffness). A two-tailed two-samples unequal variance student t-test with significance set at 0.05, found no significant difference between the treatment groups for load-to-failure (p = 0.2174) and stiffness (p = 0.8286).

Role of MR imaging in the management of injuries in professional football players

This article discusses the effectiveness of MR imaging in evaluating the injuries of both upper and lower extremities in the professional football player. Topics include bone, joint and soft tissue disorders, and injuries resulting from overuse or trauma of the shoulder, elbow, forearm, and wrist; the pelvis and hip, lower extremity muscle and tendon, knee, and ankle.

Shoulder rehabilitation for the arthritic glenohumeral joint: preoperative and postoperative considerations

Arthritis of the glenohumeral joint can cause pain, weakness, and limit motion. Preoperative treatment consists of physical therapy to manage pain, increase shoulder motion, and increase rotator cuff and scapulothoracic muscle strength. The postoperative three-phase rehabilitation program described is structured, supervised, and involves the cooperation of the patient, surgeon, and physical therapist. Rate of progression and ultimate outcome is based on underlying pathology, surgical technique, and patient tolerance to exercise. Patients with an intact rotator cuff should be expected to tolerate a more aggressive rehabilitation program and expect a higher functional outcome. Those with a deficient cuff mechanism can expect more modest gains oriented toward restoring pain-free functional activity.