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Biomedical subjects

William H Montgomery

Publications and source records attributed to William H Montgomery.

8 recordsLinked to original sources

Distal biceps tendon repair: a biomechanical comparison of intact tendon and 2 repair techniques.

BACKGROUND: A variety of techniques have been described for distal biceps tendon reattachment-bone tunnel with transosseous sutures, suture anchors, and interference screw techniques. HYPOTHESIS: There will be no significant difference between the mean failure strength, maximum strength, and stiffness of the intact specimen and repair techniques tested: bone tunnel with transosseous sutures and interference screw. STUDY DESIGN: Controlled laboratory study. METHODS: Nine matched pairs of fresh-frozen human cadaveric elbows were prepared. The intact tendon was pulled from the radial tuberosity; the right and left elbows were randomized to bone tunnels with transosseous sutures or interference screw repair techniques. The repaired specimens were pulled using the same regimen for the intact tendon. Failure strength, maximum strength, and stiffness were measured and compared. RESULTS: The mean failure strength, maximum strength, and stiffness of intact tendons were 204.3 +/- 76.9 N, 221.7 +/- 65.9 N, and 30.1 +/- 12.4 N/mm, respectively; for the interference screw specimens, 178.0 +/- 54.5 N, 192.1 +/- 53.1 N, and 30.4 +/- 9.5 N/mm, respectively; and for the bone tunnel specimens, 124.9 +/- 22.8 N, 206.6 +/- 49.8 N, and 15.9 +/- 5.6 N/mm, respectively. There were no significant differences between measures in the intact and interference screw specimens. Mean failure strength and stiffness of the bone tunnel specimens were significantly lower than those of the intact and interference screw specimens; there was no significant difference between the maximum strengths of the treatments. Interference screw failure occurred abruptly with little plastic deformation in nearly all specimens with the tendon and screw pulling out as a unit, often involving fracture of the radial wall. Two of the bone tunnels failed at the bony bridge; the remainder lost bone-tendon contact as the distal tendon was shredded by the suture. CONCLUSION: The results suggest interference screw fixation repair is nearly as strong and stiff as the intact tendon and stronger than the bone tunnel repair technique. CLINICAL RELEVANCE: The interference screw provides better stiffness and failure strength compared with the bone tunnel technique for distal biceps tendon repair. Given the superior mechanical properties, the interference screw technique is recommended as the treatment of choice for biceps tendon rupture repair.

Aged↗

Simultaneous ipsilateral posterior knee and hip dislocations: case report, including a technique for closed reduction of the hip.

In isolation, dislocations of the hip and knee require emergent reduction to minimize the risks of serious complications, including vascular and neurologic injury, osteonecrosis of the femoral head, and loss of motion and function. With simultaneous dislocation of the ipsilateral hip and knee, as in the situation of hip dislocation with concomitant femoral shaft fracture, reduction of the hip may prove difficult because of the inability to control the femoral segment. In this setting, general anesthesia is commonly required. We present the case of a patient who sustained an ipsilateral hip and knee dislocation who underwent closed reduction of the knee in the emergency department but required general anesthesia and the insertion of Schanz pins in the femur to reduce the hip dislocation.

Accidents, Traffic↗

Anteroinferior bone-grafting can restore stability in osseous glenoid defects.

BACKGROUND: Glenohumeral instability associated with a large osseous defect of the glenoid can be treated with bone graft to restore the glenoid concavity. The shape and positioning of the graft is critical: a graft that encroaches on the extrapolated glenoid curvature can prevent the head from seating completely in the glenoid, whereas a graft that is too far from the curvature does not restore the glenoid concavity. The purpose of the present study was to investigate how the intrinsic stability that is provided by the glenoid is affected by (1) a standardized anteroinferior glenoid defect and (2) different configurations of anteroinferior glenoid bone graft. METHODS: The anteroinferior stability provided by the glenoid was quantitated by measuring the balance stability angle in that direction. The balance stability angle is the maximal angle that the direction of the net humeral joint-reaction force can make with the glenoid centerline before dislocation takes place. The anteroinferior stability was assessed in each of four fresh-frozen, grossly normal cadaveric glenoids in (1) the unaltered state, (2) after the creation of a standardized defect of a magnitude that has been reported by other investigators to be sufficient to require a bone graft, and (3) after each step of a series of bone-grafting procedures involving grafts of varying height and contour. RESULTS: The anteroinferior glenoid defect significantly diminished the anteroinferior stability by almost 50% (p = 0.006). Bone-grafting significantly increased the stability provided by the glenoid. The increase in stability as compared with that of the glenoid with the standardized defect was particularly marked for contoured graft heights of 6 and 8 mm, for which the increases were 150% (p = 0.0001) and 229% (p < 0.00025), respectively. Contouring of the graft minimized the potential for unwanted contact between the ball and the graft. CONCLUSIONS: Anteroinferior shoulder instability caused by an osseous defect in the glenoid can be corrected with bone-grafting. The effectiveness of the graft in restoring the lost stability is related both to its height and to the extent to which it is contoured as long as the graft is not so prominent that it forces the ball posteriorly from the center of the glenoid.

Aged↗

Intraoperative thyroid storm: a case report.

An 18-year-old woman being treated for Graves disease underwent elective thyroidectomy. Tachycardia was noted before surgery. The patient's heart rate and temperature started to rise 30 minutes into surgery. Malignant hyperthermia was excluded on clinical grounds, and treatment with beta blockers was started. The patient's conditions stabilized, and surgery was completed. A review of the patient's laboratory test results revealed a high free thyroxine level before surgery. Diagnosis and management of thyroid storm are discussed.

Adolescent↗