AOA Critical Issues Symposium: Leadership and Education During and After COVID-19: Back to the Future or a New Normal.

ABSTRACT: The devastating impact of COVID-19 has reshaped how we lead and train our future surgeons in the field of orthopaedics. Overnight, leaders in our field had to dramatically shift their mindset to continue to lead a hospital, department, journal, or residency or fellowship program in the face of an unprecedented level of adversity in the history of the United States. This symposium discusses the role of physician leadership during and after a pandemic, as well as the adoption of technology for training surgeons in the field of orthopaedics.

Current concepts in the management of complex elbow trauma.

Complex instability of the elbow, also known as fracture dislocation of the elbow, is one of the most challenging injuries of the musculoskeletal system. A clear understanding of the biomechanics of the joint with special focus on the relative contributions of the articular components and the ligamentous constraints is critical to the proper management of these injuries. The accurate recognition and implications of associated injuries offers a rationale for approaching these difficult problems by appropriately addressing the elements of the trauma. Further, doing so in a timely fashion enhances the outcome. Currently, even the most devastating of injuries are felt to have a more favourable prognosis than was present in the past if the principles contained herein are followed.

Prosthesis design and stress profile after hip resurfacing: a finite element analysis.

PURPOSE: To evaluate the effect of prosthesis design on stress profile in the proximal femur after hip resurfacing. METHODS: The von Mises stress profile of the native femur was simulated and compared with that of resurfaced femurs using various prosthetic materials (titanium, cobalt-chrome, ceramic), stem lengths (normal, half, short, and no stem), and femoral head coverage (shell size) [260 degrees, 220 degrees, 180 degrees, and 140 degrees]. RESULTS: Hip resurfacing altered the stress profile of the cancellous (but not cortical) bone of the femoral neck. Maximal cortical stresses were observed at the posterior half of the medial femoral neck. The stress profile of the native femur was most similar to that of the resurfaced femur made of titanium, with a short or no stem and 260 degrees of femoral head coverage (shell size). CONCLUSION: Optimising prosthesis design by minimising biomechanical alterations seems a valid approach to achieving favourable long-term outcomes. Cadaveric and in vivo studies are needed to confirm the clinical relevance and feasibility.

Intra-articular implantation of collagen scaffold carriers is safe in both native and arthrofibrotic rabbit knee joints.

OBJECTIVES: Sustained intra-articular delivery of pharmacological agents is an attractive modality but requires use of a safe carrier that would not induce cartilage damage or fibrosis. Collagen scaffolds are widely available and could be used intra-articularly, but no investigation has looked at the safety of collagen scaffolds within synovial joints. The aim of this study was to determine the safety of collagen scaffold implantation in a validated in vivo animal model of knee arthrofibrosis. MATERIALS AND METHODS: A total of 96 rabbits were randomly and equally assigned to four different groups: arthrotomy alone; arthrotomy and collagen scaffold placement; contracture surgery; and contracture surgery and collagen scaffold placement. Animals were killed in equal numbers at 72 hours, two weeks, eight weeks, and 24 weeks. Joint contracture was measured, and cartilage and synovial samples underwent histological analysis. RESULTS: Animals that underwent arthrotomy had equivalent joint contractures regardless of scaffold implantation (-13.9° versus -10.9°, equivalence limit 15°). Animals that underwent surgery to induce contracture did not demonstrate equivalent joint contractures with (41.8°) or without (53.9°) collagen scaffold implantation. Chondral damage occurred in similar rates with (11 of 48) and without (nine of 48) scaffold implantation. No significant difference in synovitis was noted between groups. Absorption of the collagen scaffold occurred within eight weeks in all animals CONCLUSION: Our data suggest that intra-articular implantation of a collagen sponge does not induce synovitis or cartilage damage. Implantation in a native joint does not seem to induce contracture. Implantation of the collagen sponge in a rabbit knee model of contracture may decrease the severity of the contracture.Cite this article: J. A. Walker, T. J. Ewald, E. Lewallen, A. Van Wijnen, A. D. Hanssen, B. F. Morrey, M. E. Morrey, M. P. Abdel, J. Sanchez-Sotelo. Intra-articular implantation of collagen scaffold carriers is safe in both native and arthrofibrotic rabbit knee joints. Bone Joint Res 2016;6:162-171. DOI: 10.1302/2046-3758.63.BJR-2016-0193.

The effect of the orientation of the radial head on the kinematics of the ulnohumeral joint and force transmission through the radiocapitellar joint.

Background. The treatment of radial head fractures that are not amenable to an open reduction and internal fixation, remains to be a difficult issue. A potential problem with prosthetic replacement of the radial head is the shape of current radial head prostheses. The purpose of this study was to determine the effect of the shape of the radial head on kinematics and load transfer of the elbow. Methods. Kinematics of the elbow and radiocapitellar force transmission were measured in 6 fresh frozen upper extremities. The effect of radial head shape was tested by rotating the head 90 degrees , with a custom-made 'native' radial head prosthesis. 3-D spatial orientation of the ulna showed an average difference in ulnohumeral laxity, between the nominal and 90 degrees conditions, of 0.1 degrees throughout the arc of motion with neutral forearm rotation (maximum: 2 degrees ). Findings. We found an average difference in ulnar axial rotation, of 0.1 degrees (maximum: 1.9 degrees ). No differences showed statistical significance. Radiohumeral joint force was measured and maximally showed a 32 times increase of force in the altered shape conditions. Interpretation. Our results show that the kinematics of the elbow was not affected by altering the shape of the radial head, but it did adversely affect the forces in the radiohumeral joint. This could possibly generate degenerative changes in the elbow.

Infection in total elbow arthroplasty with stable components: outcomes of a staged surgical protocol with retention of the components.

AIMS: We describe the use of a protocol of irrigation and debridement (I&D) with retention of the implant for the treatment of periprosthetic infection of a total elbow arthroplasty (TEA). This may be an attractive alternative to staged re-implantation. PATIENTS AND METHODS: Between 1990 and 2010, 23 consecutive patients were treated in this way. Three were lost to follow-up leaving 20 patients (21 TEAs) in the study. There were six men and 14 women. Their mean age was 58 years (23 to 76). The protocol involved: component unlinking, irrigation and debridement (I&D), and the introduction of antibiotic laden cement beads; organism-specific intravenous antibiotics; repeat I&D and re-linkage of the implant if appropriate; long-term oral antibiotic therapy. RESULTS: The mean follow-up was 7.1 years (2 to 16). The infecting micro-organisms were Staphylococcus aureus in nine, coagulase-negative Staphylococcus in 13, Corynebacterium in three and other in six cases. Re-operations included three repeat staged I&Ds, two repeat superficial I&Ds and one fasciocutaneous forearm flap. One patient required removal of the implant due to persistent infection. All except three patients rated their pain as absent or mild. Outcome was rated as good or excellent in 15 patients (mean Mayo Elbow Performance Score 78 points, (5 to 100) with a mean flexion-extension arc of 103° (40° to 150°)). CONCLUSION: A staged protocol can be successful in retaining stable components of an infected TEA. Function of the elbow may compare unfavourably to that after an uncomplicated TEA. Cite this article: Bone Joint J 2016;98-B:976-83.

Effectiveness of rosiglitazone in reducing flexion contracture in a rabbit model of arthrofibrosis with surgical capsular release: A biomechanical, histological, and genetic analysis.

AIMS: Animal models have been developed that allow simulation of post-traumatic joint contracture. One such model involves contracture-forming surgery followed by surgical capsular release. This model allows testing of antifibrotic agents, such as rosiglitazone. METHODS: A total of 20 rabbits underwent contracture-forming surgery. Eight weeks later, the animals underwent a surgical capsular release. Ten animals received rosiglitazone (intramuscular initially, then orally). The animals were sacrificed following 16 weeks of free cage mobilisation. The joints were tested biomechanically, and the posterior capsule was assessed histologically and via genetic microarray analysis. RESULTS: There was no significant difference in post-traumatic contracture between the rosiglitazone and control groups (33° (standard deviation (sd) 11) vs 37° (sd14), respectively; p = 0.4). There was no difference in number or percentage of myofibroblasts. Importantly, there were ten genes and 17 pathways that were significantly modulated by rosiglitazone in the posterior capsule. DISCUSSION: Rosiglitazone significantly altered the genetic expression of the posterior capsular tissue in a rabbit model, with ten genes and 17 pathways demonstrating significant modulation. However, there was no significant effect on biomechanical or histological properties.Cite this article: M. P. Abdel. Effectiveness of rosiglitazone in reducing flexion contracture in a rabbit model of arthrofibrosis with surgical capsular release: A biomechanical, histological, and genetic analysis. Bone Joint Res 2016;5:11-17. doi: 10.1302/2046-3758.51.2000593.

Intrinsic constraint of unlinked total elbow replacements--the ulnotrochlear joint.

BACKGROUND: Many unlinked total elbow replacement designs with radically differing articular geometries exist, suggesting that there is no consensus regarding an optimal design. A feature inherent to the articular design is the intrinsic constraint afforded to the joint by the implant. Our aim was to compare the intrinsic constraints of unlinked implants with that of the normal ulnotrochlear joint. METHODS: We tested twelve cadaveric ulnotrochlear joints with a custom-made multiple-axis materials testing machine. With compressive loads ranging from 10 to 100 N, the joints were moved in either valgus or varus directions at 90 degrees of flexion. The ulnotrochlear components from a single example of five medium-sized unlinked elbow replacements (Ewald, Kudo, Pritchard ERS, Sorbie-Questor, and Souter-Strathclyde) were also tested. The recorded measurements included the torques and forces, angular displacement, and axial displacement of the humerus relative to the ulna. RESULTS: In general, the peak torque and the constraint ratio significantly increased with increasing compressive load for the implants as well as for the normal elbow. In valgus displacement, the Souter-Strathclyde implant had the highest and the Sorbie-Questor had the smallest peak torque and the Souter-Strathclyde had the highest and the Ewald had the smallest constraint ratio. In varus displacement, the Kudo had the highest and the Ewald had the smallest peak torque and constraint ratio. CONCLUSIONS: The constraint ratio is a characteristic that is useful for describing elbow joint behavior and for comparing the behavior of implants with that of the human elbow. Of the unlinked implants tested, the Souter-Strathclyde and Kudo prostheses most closely approximated the behavior of the human elbow joint. Implants that resemble the human elbow in appearance do not replicate normal behavior consistently, whereas other implants that do not resemble the human elbow closely do not deviate markedly from human behavior. Thus, much basic information about elbow form and function is needed to improve the performance of total elbow prostheses.

Total elbow arthroplasty after previous resection of the radial head and synovectomy.

We examined the effects of previous resection of the radial head and synovectomy on the outcome of subsequent total elbow arthroplasty in patients with rheumatoid arthritis. Fifteen elbows with a history of resection and synovectomy were compared with a control group of patients who had elbow arthroplasty with an implant of the same design. The mean age in both groups was 63 years. In the study group, resection of the radial head and synovectomy had been undertaken at a mean of 8.9 years before arthroplasty. The mean radiological follow-up for the 13 available patients in the study group was 5.89 years (0.3 to 11.0) and in the control group was 6.6 years (2.2 to 12.6). There were no revisions in either group. The mean Mayo elbow performance score improved from 29 to 96 in the study group, with similar improvement in the control group (28 to 87). The study group had excellent results in 13 elbows and good results in two. The control group had excellent results in seven and good results in six. Our experience indicates that previous resection of the radial head and synovectomy are not associated with an increased rate of revision following subsequent arthroplasty of the elbow. However, there was a higher rate of complication in the study group compared with the control group.

Ligamentous repair and reconstruction for posterolateral rotatory instability of the elbow.

We describe the intermediate results of lateral ligamentous repair or reconstruction for posterolateral rotatory instability of the elbow. Between 1986 and 1999, we performed 12 direct repairs and 33 ligament reconstructions with a tendon autograft. One patient was lost to follow-up and 44 were retrospectively studied at a mean of six years (2 to 15). Surgery restored stability in all except five patients. In two the elbow became stable after a second procedure. The mean post-operative Mayo elbow performance score was 85 points (60 to 100). The result was classified as excellent in 19, good in 13, fair in seven and poor in five patients. Thirty-eight patients (86%) were subjectively satisfied with the outcome of the operation. Better results were obtained in patients with a post-traumatic aetiology (p = 0.03), those with subjective symptoms of instability at presentation (p = 0.006) and those who had an augmented reconstruction using a tendon graft (p = 0.04). Reconstruction using a tendon graft seems to provide better results than ligament repair and the results do not seem to deteriorate with time. The outcome of this procedure is less predictable in patients with no subjective instability.

Coonrad-Morrey total elbow arthroplasty for tumours of the distal humerus and elbow.

We reviewed 20 patients who had undergone a Coonrad-Morrey total elbow arthroplasty after resection of a primary or metastatic tumour from the elbow or distal humerus between 1980 and 2002. Eighteen patients underwent reconstruction for palliative treatment with restoration of function after intralesional surgery and two after excision of a primary bone tumour. The mean follow-up was 30 months (1 to 192). Five patients (25%) were alive at the final follow-up; 14 (70%) had died of their disease and one of unrelated causes. Local control was achieved in 15 patients (75%). The mean Mayo Elbow Performance Score improved from 22 (5 to 45) to 75 points (55 to 95). Four reconstructions (20%) failed and required revision. Seven patients (35%) had early complications, the most frequent being nerve injury (25%). There were no infections or wound complications although 18 patients (90%) had radiotherapy, chemotherapy or both. The Coonrad-Morrey total elbow arthroplasty provides good relief from pain and a good functional outcome after resection of tumours of the elbow. The rates of complications involving local recurrence of tumour (25%) and nerve injury (25%) are of concern.

The kinematic importance of radial neck length in radial head replacement.

Comminuted radial head fractures can be treated with a radial head implant. The effects of lengthening (2.5 mm, 5 mm) and shortening (2.5 mm, 5 mm) of the radial neck, were compared to the nominal length in six human upper extremity cadavers. Total varus-valgus laxity and ulnar rotation were recorded. We hypothesized that restoring the exact length of the radius is important to maintain normal kinematics in the elbow joint. Lengthening or shortening of more than 2.5 mm significantly changed elbow kinematics. Lengthening caused a significant decrease (p < 0.001) in varus-valgus laxity, with the ulna tracking in varus and external rotation. Shortening caused a significant increase in varus-valgus laxity (p < 0.001) and ulnar rotation (p < 0.001), with the ulna tracking in valgus and internal rotation. Our study suggests that a restoration of radial length is important and that axial understuffing or overstuffing the radiohumeral joint by 2.5 mm or more, will alter elbow kinematics.

Rheumatoid pseudocyst (geode) of the femoral neck without apparent joint involvement.

Typically, rheumatoid cysts are associated with obvious joint involvement and are located in the subchondral portion of the adjacent joint. Giant pseudocysts (geodes) are uncommon and are characteristically associated with extensive joint destruction. The patient described in this report had a giant pseudocyst of the femoral neck but no joint involvement. To the best of my knowledge, this is the first report of such a manifestation of a giant pseudocyst. As such, it posed a somewhat difficult diagnostic problem.

Ankle instability: current concepts, diagnosis, and treatment.

Our approach to the problem of ankle sprains and instability is reviewed. After diagnostic evaluation (including stress roentgenography, arthrography, or tenography if necessary), most of our patients are treated either by taping if they have a grade 1 or 2 sprain or by casting if they have a grade 3 disruption. If the injury should progress to chronic instability despite this treatment regimen, which is an unusual occurrence, satisfactory reconstructive procedures are available. Indications for acute primary repair are limited.

Total joint arthroplasty. The elbow.

The first total elbow arthroplasty at the Mayo Clinic was performed in 1972, and it provided markedly superior results compared with previously performed procedures for elbow arthritis. However, a high revision rate (14%), due mainly to loosening (75%), tempered early enthusiasm for the procedure. Prospects for improved design and surgical technique based on our clinical experience and biomechanical data are encouraging. For the present, however, more limited procedures are recommended, and the total elbow arthroplasty is reserved for only a relatively few patients for whom there are no other viable surgical options.

Hematogenous osteomyelitis at uncommon sites in children.

The diagnosis of hematogenic osteomyelitis is often delayed in children if it involves uncommon sites such as the pelvis, clavicle, or calcaneus. Although parenterally administered antibiotics may control the disease process in the acute stage, abscess formation requires incision and drainage. Staphylococcus aureus was the most common organism in this series, and it usually was penicillin resistnat. When the condition is diagnosed early and is properly treated with at least 3 weeks of antibiotic therapy and judicious surgical intervention, recurrences are rare and morbidity is minimal.

Venous thromboembolism associated with hip and knee arthroplasty: current prophylactic practices and outcomes.

Joint registry and hospital data bases for 5,024 total hip and total knee arthroplasties done between 1986 and 1988 at the Mayo Clinic were used to study prophylactic measures and frequency of symptomatic deep venous thrombosis and pulmonary embolism. In virtually all patients, graduated compression stockings were used, with or without another type of prophylaxis. Only 44 of 3,115 patients who underwent hip arthroplasty (1.4%) and 32 of 1,909 patients who underwent knee arthroplasty (1.7%) had definite or probable deep venous thrombosis or pulmonary embolism. Death definitely or possibly attributable to pulmonary embolism occurred in 11 patients who underwent hip arthroplasty (0.35%) and 1 patient who underwent knee arthroplasty (0.05%). Although patients with a history of deep venous thrombosis or pulmonary embolism were more likely to receive warfarin than were patients without such a history, the relative risk of symptomatic deep venous thrombosis or pulmonary embolism in patients who underwent hip arthroplasty and received warfarin postoperatively was approximately half that in patients who received other types of prophylaxis. The risk of death from pulmonary embolism was similarly diminished in the group that received warfarin. The lower rates of these complications in the patients who received warfarin support the prophylactic use of this agent after total hip arthroplasty.

Total joint arthroplasty. The role of biomechanics.

The role of biomechanics is intricately involved in total joint replacement from its inception to its clinical use. By integrating knowledge of joint function and material properties, the artificial joint is designed and tested. After clinical use, the joint function is again studied and failure modes are defined. Biomechanics is the single most important discipline that can be employed to study the cause of failure in order to improve design and technique. This will increase the reliability of, and decrease the incidence of failure associated with, total joint replacement.

Superior-inferior stability of the shoulder: role of the coracohumeral ligament and the rotator interval capsule.

OBJECTIVE: To study the superior-inferior stabilizing functions of the coracohumeral ligament (CHL) and the rotator interval capsule (RIC) with use of a material testing machine. MATERIAL AND METHODS: The axial translations of the humerus with the superior-inferior translation force of 30 N applied were recorded under the following joint capsule conditions: (1) intact, (2) vented, (3) the CHL sectioned, and (4) the RIC incised in six cadaver shoulders. The order of sectioning was changed for conditions 3 and 4 in six other cadaver shoulders. RESULTS: With the arm in internal and neutral rotations, venting the capsule significantly increased the superior-inferior translation, which was unaffected by further sectioning of the CHL and the RIC. With the arm in external rotation, only the CHL contributed significantly to inferior stability, whereas both this ligament and the RIC contributed to superior stability to a lesser degree. CONCLUSION: The CHL is a stabilizer in superior inferior directions with the arm in external rotation, and the intra-articular pressure that is maintained by the intact RIC is a stabilizer in superior-inferior directions with the arm in internal and neutral rotations. These findings may provide a scientific background to support closure of the interval space to stabilize the shoulder and may explain part of the superior instability observed in shoulders with rotator cuff tears.