Morrey, B.F.

This study reports our experience with total elbow replacement for fused elbows. Between 1982 and 2004, 13 patients with spontaneously ankylosed elbows were treated with a linked semi-constrained non-custom total elbow implant. The mean age at operation was 54 years (24 to 80). The stiffness was a result of trauma in ten elbows, juvenile rheumatoid arthritis in one, and rheumatoid arthritis in two. The patients were followed for a mean of 12 years (2 to 26) and were evaluated clinically using the Mayo Elbow Performance Score, as well as radiologically. A mean arc from 37° of extension to 118° of flexion was achieved. Outcomes were good or excellent for seven elbows at final review. Ten patients felt better or much better after total elbow replacement. However, there was a high complication rate and re-operation was required in over half of patients. Two developed peri-operative soft-tissue breakdown requiring debridement. A muscle flap with skin grafting was used for soft-tissue cover in one. Revision was undertaken in one elbow following fracture of the ulnar component. Three patients developed a deep infection. Three elbows were manipulated under anaesthesia for post-operative stiffness. Prophylactic measures for heterotopic ossification were unsuccessful. Total elbow replacement for the ankylosed elbow should be performed with caution. However, the outcome can be reliable in the long term and have a markedly positive impact on patient function and satisfaction. The high potential for complications must be considered. We consider total elbow replacement to be an acceptable procedure in selected patients with reasonable expectations.

The contribution of axial arm rotation to translation of the humeral head with the arm in the hanging position was examined using nine fresh-frozen cadaveric shoulders. Three standard clinical tests were simulated: anterior and posterior translation and sulcus tests. In both the anterior translation and sulcus tests, anterior and infe rior displacements were significantly restricted in inter nal rotation but not in neutral and external rotation. In the posterior translation test, no significant differences in displacement could be observed in internal, neutral, or external rotation. Since anterior and inferior translations of the humeral head were significantly affected by the rotation of the arm, we recommend that the anterior translation and sulcus tests be performed in various rotations.

The histopathologic features from 11 patients who were treated surgically for lateral epicondylitis were graded and compared to similar tissue from 12 cadaveric spec imens. All studies were done by a single pathologist who had no knowledge of the origin of the specimen. The surgical specimens were interpreted as abnormal in all 11 specimens, and all 12 of the control specimens were reported as being without histologic abnormality. Vascular proliferation was present in 10 of 11 and focal hyaline degeneration was recorded in all 11 of the surgical specimens. Neither feature was present in any of the control material (P < 0.001). These data suggest that chronic refractory lateral epicondylitis requiring sur gery is a degenerative rather than inflammatory proc ess. This may account for the lack of response to rest and antiinflammatory medication.

This study analyzed forces in the tibiofemoral and pa tellofemoral joints during isokinetic exercise using an analytical biomechanical model. The results show that isokinetic exercise can produce large loads on these joints, especially during extension exercises. The tibio femoral compressive force (4.0 body weight) is approx imately equal to that obtained during walking but it occurs at 55° of knee flexion. Anterior shear forces (resisting force to anterior drawer) exist during exten sion exercise at less than 40° of knee flexion, with a maximum of 0.3 body weight. Posterior shear forces (resisting force to posterior drawer) exist during exten sion exercise at knee joint angles greater than 40° and during the flexion portion of isokinetic exercise. The maximum posterior shear force is 1.7 body weight. The patellofemoral joint can encounter loads as high as 5.1 body weight which are 10 times higher than during straight leg raises. These results suggest that isokinetic exercise should be used cautiously in patients with knee lesions.

The purpose of this study was to investigate the rela tionship of isometric and isokinetic endurance of the forearm complex under maximum effort in a healthy population. Isometric and isokinetic endurance meas urements of elbow flexion and extension of the domi nant and nondominant sides were made in 32 healthy male subjects (age range, 21 to 39 years). Both fatigue rates and the amount of time elapsed in reaching fatigue were determined. Analysis of these data reveals that 1) isometric endurance of the forearm complex cannot be used as a predictor of isokinetic endurance, as there is no relationship between the two, 2) dominant and non dominant endurance are related, a result that supports the belief that in the assessment of the endurance of a single diseased upper extremity, the best available comparison is with the contralateral healthy extremity, and 3) healthy males in the age range tested have greater endurance in elbow extension than in flexion.

The methods and materials for ACL reconstruction are important issues for the practicing orthopaedic sur geon. In this study a model was developed to study the biological and biomechanical characteristics of a patel lar tendon autograft used for ACL reconstruction. Spe cifically it was hypothesized that since vascularity of these grafts reflects their "healthiness," strength and vascularity should be inversely related in the early pe riod after implantation. Using an over the top technique, a patellar tendon graft was placed in three groups of dogs and studied at 37, 57, and 120 days. Vascularity of the grafts was measured using technetium-tagged red blood cells, and percent water by weight was determined by dessication. Tensile testing to failure was performed using an MTS machine. The grafts became more vascular, more hydrated, less stiff, and less strong (by 4 weeks) than controls. By 16 weeks the vascular response was subsiding but the grafts remained only 40% as strong as controls. Percent water increased significantly over controls for all time periods. Decrease in strength correlated poorly with vascularity but correlated well with increase in percent water. These findings suggest that the change in strength of an intraarticular ACL replacement relates more to a basic rearrangement of its collagen-ground substance relationships, and that vascularity may re flect the inflammatory response bringing about these changes. The model developed in this study serves as a basis for further studies, and the findings reveal important information about the behavior of ACL graft ing materials.

The stabilizing capacity of the ligaments and articular surface in the ankle was determined under defined physiologic loading conditions. The concept of primary and secondary constraints was adapted to the ankle. With physiologic loading, the articular surface ac counted for 30% and 100% of stability in rotation and version, respectively. That the articular surface was the sole source of inversion and eversion stability under the prescribed physiologic loading conditions has not been previously reported. The demonstration that the articular surface resists inversion displacement in the loaded ankle supports the conclusion of previous studies that rotation, rather than inversion, may account for a type of clinically sympto matic ankle instability. Further, ankle instability may occur during loading and unloading but not once the ankle is fully loaded. The results of our study confirm the importance of the anterior talofibular and calcaneo fibular ligaments and suggest an important role for the deltoid ligament.

This preliminary study of four elbow specimens inves tigates the relationship of articular geometry and liga mentous structures in providing stability to the elbow joint. A technique is presented that describes the con straining features of varus-valgus and distraction in extension and at 90° of elbow flexion. Valgus stability is equally divided among the medial collateral ligament, anterior capsule, and bony articulation in full extension; whereas, at 90° of flexion the contribution of the ante rior capsule is assumed by the medial collateral ligament which provides approximately 55% of the stabilizing contribution to valgus stress. Varus stress is noted to be resisted primarily by the anterior capsule (32%) and the joint articulation (55%) with only a small (14%) contribution from the radial collateral ligament. At 90° of flexion, little change is noted in the contribution to the radial collateral ligament (9%), but the anterior capsule offers only 13%, with the remaining stability (75%) arising from the joint articulation. In extension, the soft tissue resistance to distraction is provided minimally by either the radial (5%) or the medial (5%) collateral ligaments, and thus primarily originates from the anterior capsule (85%). At 90° of flexion, however, the capsule offers virtually no resistance to distraction (8%). The radial collateral ligament contributes 10% of the stability, while the medial collateral ligament ac counts for 78% of the resistance to distraction in this position. Too few specimens have been studied to form any conclusions for direct clinical applications at this time. However, the technique provides a reliable tool with additional studies for different positions and loading conditions underway. These efforts should disclose useful information that might be applied to the manage ment of chronic elbow instability, radial head or olecra non fracture, the design and implantation of elbow prostheses, or provide a rationale for other reconstruc tive procedures.