Biomedical subjects
Publications and source records attributed to Roger P van Riet.
A patient presented with chronic shoulder pain from a rare plasmocytoma in the distal humerus that resolved following a pathologic fracture. Staged reconstruction of the elbow after resection of the tumor in the distal humerus resulted in resolution of the patient's elbow and shoulder symptoms.
The extensor mechanism of the hand is complex, requiring effective functioning of all involved structures, including the sagittal bands. The sagittal bands function to maintain the extensor tendons in midline and to limit their distal excursion. Injury to the sagittal bands or sagittal band attenuation can cause instability and ulnar displacement/subluxation of the extensor tendons into the valleys between the digits and lead to a subsequent loss of active finger extension at the metacarpophalangeal joints. Secondary conditions may also develop, such as swan-neck deformity, as is frequently observed in the rheumatoid arthritis population. To prevent or reduce an extension lag and secondary changes and to maintain the functional use of the hand, a dynamic metacarpophalangeal extension assist splint is necessary. This splint enables extension at the metacarpophalangeal joints, thus enabling the functional use of the hand. This article reviews the biomechanics of the sagittal bands and the corrections that enable finger extension at the metacarpophalangeal joints, thus preventing secondary conditions.
Reconstructing elbow instability remains a challenging problem. Techniques described have included techniques for the lateral ligamentous complex, including the lateral ulnar collateral ligament, and techniques to reconstruct the medial collateral ligament. We describe a new circumferential technique to reconstruct both the lateral and medial ligament complexes, using 1 circular graft. A hole is drilled through the center of rotation of the distal humerus and through the insertion sites of the medial and lateral ligament complexes. A hamstring tendon graft is passed through the humerus twice to reconstruct the anterior and posterior bands of the medial collateral ligament and sutured onto itself. Endobutton fixation is used to fix the graft on either side of the ulna. The graft is tightened on the lateral and medial sides and fixed into the humerus using interference fit screws. Advantages of the technique described include stabilization of both the medial and lateral ligament complexes with 1 graft. The strength of fixation allows for individual tensioning in all limbs of the reconstruction and the multiple passes of the graft through a single humeral tunnel increasing the strength of the reconstruction. Potential complications could include ulnar nerve damage, recurrent instability, elbow stiffness, and wound breakdown. Complications related to the potential use of a hinged external fixator are not specific to this procedure but can be associated. Early active mobilization can be initiated because of the strong stability provided by the circumferential graft and good fixation.
UNLABELLED: Treatment of radial head fractures may be complicated because of the presence of associated lesions. However, little is known about the frequency or relevance of associated lesions in different types of radial head fractures. We studied the demographics of radial head fractures focusing on associated lesions in 333 adults from 1997 to 2002. The mean age of the patients was 45 years (range, 18-82 years). Two hundred twenty-three (67%) patients had Mason Type 1 fractures, 46 patients had Mason Type 2 (14%) fractures, and 64 patients had Mason Type 3 (19%) fractures. One hundred eighteen of 333 patients (39%) had associated fractures or soft tissue injury. Fifty-three (16%) patients had coronoid fractures, and 45 patients (14%) had elbow dislocations. Two hundred thirty-five (71%) patients had nonoperative treatment, which failed in six (3%) patients. Sixty-six (20%) patients had open reduction and internal fixation, which failed in six (9%) patients. Resection was used in 20 (6%) patients, and radial head replacement was used in 31 (9%) patients, one of which was revised. The ligamentous injury required surgical repair or reconstruction in 44 patients. A concurrent coronoid fracture was the most common associated injury prompting referral to this tertiary medical center. LEVEL OF EVIDENCE: Diagnostic study, Level IV (case-control study). See the Guidelines for Authors for a complete description of levels of evidence.
PURPOSE: The purpose of this study was to define the shape of the radial head by identifying the relationship between precisely defined axes of the radial head. METHODS: An anatomic study was done to define the shape of the radial head and specifically the relationship between the long and the short axis. Twenty-seven cadaveric upper extremities were used. The x and y axes of the radial head were defined in relationship to the radial notch of the ulna, with the forearm in neutral position. Outer diameters of the x and y axis were measured. These were compared with the actual maximum and minimum diameters of the radial head. X and y diameters of the articulating surface of the radial head also were measured. RESULTS: Paired 1-tailed Student's t-tests were used to compare the x and y diameters of the radial head. Regression analysis of x and y diameters of the radial head was done to identify a correlation between these parameters.Paired 1-tailed Student's t-tests showed a significant difference between X and Y diameters of the radial head. Regression analysis of x and y diameters of the radial head showed a strong correlation between these 2 axes. CONCLUSIONS: The radial head is not round. A strong correlation exists between the x and y diameters of the radial head. The orientation of the long axis is perpendicular to the radial notch with the forearm in neutral rotation. This finding will make it possible to approach the anatomy of the radial head more closely when designing radial head prostheses. The definition of the axes can be used as a guide when implanting the radial head prosthesis.
BACKGROUND: Distal triceps tendon ruptures occur rarely, and the diagnosis is often missed when the injury is acute. The literature provides little guidance regarding treatment or the outcome of treatment of these injuries. The goal of this report was to present our experience with the diagnosis, timing and technique of surgical treatment, and outcome of treatment of distal triceps tendon ruptures in twenty-two patients. None of the ruptures followed joint replacement. METHODS: Twenty-three procedures were performed in twenty-two patients with an average age of forty-seven years. The average duration of follow-up was ninety-three months (range, seven to 264 months). Data were obtained by a retrospective review of records and radiographs before and after surgery. Also, thirteen patients returned for follow-up and were examined clinically. Six additional patients responded to a telephone questionnaire. One patient was lost to follow-up, and two had died. Formal biomechanical evaluation of isokinetic strength and isokinetic work was performed in eight patients, at an average of eighty-eight months after surgery. Isokinetic strength data were available from the charts of two additional patients. RESULTS: Ten of the triceps tendon ruptures were initially misdiagnosed. At the time of diagnosis, triceps weakness with a decreased active range of motion was found in most patients, and a palpable defect in the tendon was noted after sixteen ruptures. Operative findings revealed a complete tendon rupture in eight cases and partial injuries in fifteen. Fourteen primary repairs and nine reconstructions of various types were performed. Three of the primary repairs were followed by rerupture. At the time of follow-up, the range of elbow motion averaged 10 degrees to 136 degrees. All but two elbows had a functional range of motion; however, the lack of a functional range in the two elbows was probably due to posttraumatic arthritis and not to the triceps tendon rupture. Triceps strength was noted to be 4/5 or 5/5 on manual testing in all examined subjects. Isokinetic testing of ten patients showed that peak strength was, on the average, 82% of that of the untreated extremity. Testing showed the average endurance of the involved extremity to be 99% of that of the uninvolved arm. The results after repair and reconstruction were comparable, but the patients' recovery was slower after reconstruction. CONCLUSIONS: The diagnosis of distal triceps tendon rupture is often missed when the injury is acute because of swelling and pain. Primary repair of the ruptured tendon is always possible when it is performed within three weeks after the injury. When the diagnosis is in doubt immediately after an injury, the patient should be followed closely and should be reexamined after the swelling and pain have diminished so that treatment can be instituted before the end of this three-week period. Reconstruction of the tendon is a much more complex, challenging procedure, and the postoperative recovery is slower. Thus, we believe that early surgical repair, within three weeks after the injury, is the treatment of choice for distal triceps tendon ruptures. of evidence.
Results of the treatment of the deficient coronoid and chronic elbow instability have not been reported. The purpose of this study was to analyze the results of structural bone graft for reconstruction of the coronoid process. Structural bone graft was used to reconstruct the coronoid process of 6 patients. All injuries were of the terrible triad: fracture of the coronoid, radial head fracture, and collateral ligament disruption. All cases had persistent posterior subluxation averaging 6 months (range, 1-13 months before reconstruction. Patient charts, surgical records, and radiographs were reviewed. All patients were contacted at a mean of 64 months after treatment to answer a specific set of questions to determine the Mayo Elbow Performance score. In 1 patient, radiographs showed complete resorption of the graft and severe osteoarthritis of the elbow at 54 months after surgery (case 4). The Mayo Elbow Performance score showed 1 excellent, 2 good, 1 fair, and 2 poor results. Structural bone graft may be a useful option for a deficient coronoid process and an unstable elbow, but the outcome is unpredictable.