Shiley Center for Orthopaedic Research and Education at Scripps Clinic

La Jolla, CA, United States

Shiley Center for Orthopaedic Research and Education at Scripps Clinic

La Jolla, CA, United States

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D'Lima D.D.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic | Fregly B.J.,University of Florida | Colwell Jr. C.W.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic
Arthritis Research and Therapy | Year: 2012

Stresses and strains are major factors influencing growth, remodeling and repair of musculoskeletal tissues. Therefore, knowledge of forces and deformation within bones and joints is critical to gain insight into the complex behavior of these tissues during development, aging, and response to injury and disease. Sensors have been used in vivo to measure strains in bone, intraarticular cartilage contact pressures, and forces in the spine, shoulder, hip, and knee. Implantable sensors have a high impact on several clinical applications, including fracture fixation, spine fixation, and joint arthroplasty. This review summarizes the developments in strain-measurement-based implantable sensor technology for musculoskeletal research. © 2013 BioMed Central Ltd.


Meyer A.J.,University of Florida | D'Lima D.D.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic | Besier T.F.,University of Auckland | Lloyd D.G.,Griffith University | And 2 more authors.
Journal of Orthopaedic Research | Year: 2013

Mechanical loading is believed to be a critical factor in the development and treatment of knee osteoarthritis. However, the contact forces to which the knee articular surfaces are subjected during daily activities cannot be measured clinically. Thus, the ability to predict internal knee contact forces accurately using external measures (i.e., external knee loads and muscle electromyographic [EMG] signals) would be clinically valuable. We quantified how well external knee load and EMG measures predict internal knee contact forces during gait. A single subject with a force-measuring tibial prosthesis and post-operative valgus alignment performed four gait patterns (normal, medial thrust, walking pole, and trunk sway) to induce a wide range of external and internal knee joint loads. Linear regression analyses were performed to assess how much of the variability in internal contact forces was accounted for by variability in the external measures. Though the different gait patterns successfully induced significant changes in the external and internal quantities, changes in external measures were generally weak indicators of changes in total, medial, and lateral contact force. Our results suggest that when total contact force may be changing, caution should be exercised when inferring changes in knee contact forces based on observed changes in external knee load and EMG measures. Advances in musculoskeletal modeling methods may be needed for accurate estimation of in vivo knee contact forces. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.


Hoenecke H.R.,Scripps Research Institute | Hoenecke H.R.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic | Tibor L.M.,Sierra Park Orthopedics and Sports Medicine | D'Lima D.D.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic
Journal of Shoulder and Elbow Surgery | Year: 2012

Background: Glenoid retroversion is thought be important in shoulder stability before and after shoulder arthroplasty; thus, many authors recommend glenoid reaming to correct retroversion and improve stability. Genetic analysis has revealed that glenoid vault and scapular development are controlled by different genes and environmental factors, resulting in diverse glenoid morphologies. We therefore analyzed the relative contribution of glenoid morphology and version to humeral head position. Materials and methods: We obtained 121 shoulder computed tomography scans preoperatively for shoulder arthroplasty. Humeral subluxation and glenoid version were measured on the axial image at the middle of each glenoid. Glenoid morphology was characterized as biconcave, worn, displaced, dysplastic, angled, or neutral. The strength of the correlation between humeral subluxation, glenoid version, and glenoid morphology was analyzed. Results: Glenoid version did not correlate with humeral subluxation. The highest frequency of posterior subluxation was noted in biconcave glenoids. Shoulders with other glenoid morphologies were more likely to have anterior or central positioning of the humerus. The mean subluxation ratio for biconcave glenoids was 0.56 and was significantly different from all other morphologies (P < .02). Discussion/Conclusion: Even in the arthritic shoulder, glenoid orientation does not appear to explain the complex biomechanics of shoulder stability. The causes of humeral head subluxation before and after total shoulder arthroplasty are likely multifactorial and may include static and dynamic soft-tissue forces. The biconcave glenoid deserves more attention at surgery because of the high association with posterior subluxation. © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees.


Bunn A.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic
Journal of orthopaedic research : official publication of the Orthopaedic Research Society | Year: 2014

Hip dislocation is a major short-term complication after total hip arthroplasty (THA). One factor thought to reduce the risk for dislocation is head size. We constructed subject-specific computer models to study the effect of head size on risk for postoperative dislocation. Femoral and acetabular geometry was constructed after segmenting CT scans of nine hips. CAD models of THA components with four head diameters (28, 32, 36, and 44 mm) were virtually implanted. Hip capsular ligaments were simulated using rigid-body ellipsoids connected by non-linear springs. Posterior dislocation was simulated during a rise from a low chair; anterior dislocation was simulated during a pivot activity. Intraoperative stability tests were simulated for anterior or posterior dislocation. While rising from a low chair (posterior dislocation) and during the pivot activity (anterior dislocation), increasing head size significantly increased hip flexion angle at dislocation and generated higher dislocation moments. Larger heads reduced the risk for dislocation. Intraoperative stability tests detected the relative increased resistance to dislocation despite differences in the absolute magnitude of moments. This model can be useful preclinical tool for assessing design changes, the effect of component placement, and the activity-based risk for dislocation. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.


Kersten A.D.,a service of Park Ridge Health | Flores-Hernandez C.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic | Hoenecke H.R.,Scripps Research Institute | D'Lima D.D.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic
Journal of Shoulder and Elbow Surgery | Year: 2015

Background and hypothesis: Total shoulder arthroplasty is recommended treatment for severe osteoarthritis of the glenohumeral joint, which often results in excessive posterior wear. Two recent glenoid components with posterior augments have been designed to correct excessive posterior wear and retroversion. Our primary hypothesis was that posterior augmented glenoid designs require less bone removal than a standard glenoid design. Methods: Ten arthritic scapulae classified as Walch B2 glenoids were virtually implanted with standard, stepped, and wedged components. The volume of surgical bone removal, the maximum reaming depth, and the portion of the implant surface in contact with cancellous vs. cortical bone were calculated for each implant. Results: The neoglenoid made up an average of 65%±12% of the glenoid width. Mean surgical bone volume removed was least for the wedged (2857±1618mm3) compared with the stepped (4307±1485mm3; P<.001) and standard (5385±2348mm3; P<.001) designs. Maximum bone depth removed for the wedged (4.2±2.0mm) was less than for the stepped (7.6±1.2mm; P<.001) and standard (9.9±3.2mm; P<.001). The mean percentage of the implant's back surface supported by cancellous bone was 18.2% for the standard, 8.8% for the stepped (P=02), and 4.3% for the wedged (P=01). Discussion: Both augmented components corrected glenoid version to neutral and required less bone removal, required less reaming depth, and were supported by more cortical bone than in the standard implant. The least amount of bone removed was with the wedged design. © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees.


Levy Y.D.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic | Levy Y.D.,Scripps Research Institute | Gortz S.,University of California at San Diego | Pulido P.A.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic | And 2 more authors.
Clinical Orthopaedics and Related Research | Year: 2013

Background: Fresh osteochondral allograft transplantation is an increasingly common treatment option for chondral and osteochondral lesions in the knee, but the long-term outcome is unknown. Questions/purposes: We determined (1) pain and function, (2) frequency and types of reoperations, (3) survivorship at a median of 13.5 years, and (4) predictors of osteochondral allograft failure in the distal femur. Methods: We evaluated 122 patients (129 knees) who underwent osteochondral allograft transplantation of the femoral condyle. Mean age was 33 years and 53% were male. Clinical evaluation included the modified Merle d'Aubigné-Postel (18-point), IKDC, and Knee Society function (KS-F) scores. We defined graft failure as revision osteochondral allografting or conversion to arthroplasty. We determined whether patient characteristics or attributes of the graft influenced failure. Minimum followup was 2.4 years (median, 13.5 years); 91% had more than 10 years of followup. Results: Mean modified Merle d'Aubigné-Postel score improved from 12.1 to 16, mean IKDC pain score from 7.0 to 3.8, mean IKDC function score from 3.4 to 7.2, and mean KS-F score from 65.6 to 82.5. Sixty-one knees (47%) underwent reoperations. Thirty-one knees (24%) failed at a mean of 7.2 years. Survivorship was 82% at 10 years, 74% at 15 years, and 66% at 20 years. Age of more than 30 years at time of surgery and having two or more previous surgeries for the operated knee were associated with allograft failure. Conclusions: Followup of femoral condyle osteochondral allografting demonstrated durable improvement in pain and function, with graft survivorship of 82% at 10 years. Level of Evidence: Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence. © 2012 The Association of Bone and Joint Surgeons®.


Ezzet K.A.,Scripps Research Institute | McCauley J.C.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic
Journal of Arthroplasty | Year: 2014

Proper femoral and acetabular component position and leg length equality are important intraoperative considerations during total hip arthroplasty. Unfortunately, traditional surgical techniques often lead to suboptimal component position, and such deviations have been associated with increased rates of prosthetic wear, dislocation, component loosening, and patient dissatisfaction. Although surgical navigation has been shown to improve reproducibility of component alignment, such technology is not universally available and is associated with significant costs and additional surgical/anesthetic time. In the current study, we found that a routine intraoperative pelvic radiograph could successfully identify malpositioned components and leg length inequalities and could allow for successful correction of identified problems. Unexpected component malposition and leg length inequality occurred in only 1.5% of cases where an intraoperative pelvic radiograph was utilized. © 2014 Elsevier Inc.


Sovani S.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic | Grogan S.P.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic
Orthopaedic Nursing | Year: 2013

Osteoarthritis (OA) is a disease of the joint, and age is the major risk factor for its development. Clinical manifestation of OA includes joint pain, stiffness, and loss of mobility. Currently, no pharmacological treatments are available to treat this specific joint disease; only symptom-modifying drugs are available. Improvement in imaging technology, identification of biomarkers, and increased understanding of the molecular basis of OA will aid in detecting the early stages of disease. Yet the development of interventional strategies remains elusive and will be critical for effective prevention of OA-associated joint destruction. The potential of cell-based therapies may be applicable in improving joint function in mild to more advanced cases of OA. Ongoing studies to understand the basis of this disease will eventually lead to prevention and treatment strategies and will also be a key in reducing the social and economic burden of this disease. Nurses are advised to provide an integrative approach of disease assessment and management in OA patients' care with a focus on education and implementation. Knowledge and understanding of OA and how this affects the individual patient form the basis for such an integrative approach to all-round patient care and disease management. © 2013 by National Association of Orthopaedic Nurses.


Hoenecke H.R.,Scripps Research Institute | Flores-Hernandez C.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic | D'Lima D.D.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic
Journal of Shoulder and Elbow Surgery | Year: 2014

Background: Medialization of the glenohumeral center of rotation alters the moment arm of the deltoid, can affect muscle function, and increases the risk for scapular notching due to impingement. The objective of this study was to determine the effect of position of the glenosphere on deltoid efficiency and the range of glenohumeral adduction. Methods: Scapulohumeral bone models were reconstructed from computed tomography scans and virtually implanted with primary or reverse total shoulder arthroplasty implants. The placement of the glenosphere was varied to simulate differing degrees of "medialization" and inferior placement relative to the glenoid. Muscle and joint forces were computed during shoulder abduction in OpenSim musculoskeletal modeling software. Results: The average glenohumeral joint reaction forces for the primary total shoulder arthroplasty were within 5% of those previously reported invivo. Superior placement or full lateralization of the glenosphere increased glenohumeral joint reaction forces by 10% and 18%, respectively, relative to the recommended reverse total shoulder arthroplasty position. The moment arm of the deltoid muscle was the highest at the recommended baseline surgical position. The baseline glenosphere position resulted in a glenohumeral adduction deficit averaging more than 10° that increased to more than 25° when the glenosphere was placed superiorly. Only with full lateralization was glenohumeral adduction unaffected by superoinferior placement. Discussion/Conclusion: Selecting optimum placement of the glenosphere involves tradeoffs in bending moment at the implant-bone interface, risk for impingement, and deltoid efficiency. A viable option is partially medializing the glenosphere, which retains most of the benefits of deltoid efficiency and reduces the risk for scapular notching. © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees.


Hermida J.C.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic | Flores-Hernandez C.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic | Hoenecke H.R.,Scripps Research Institute | D'Lima D.D.,Shiley Center for Orthopaedic Research and Education at Scripps Clinic
Journal of Shoulder and Elbow Surgery | Year: 2014

Background: This study undertook a computational analysis of a wedged glenoid component for correction of retroverted glenoid arthritic deformity to determine whether a wedge-shaped glenoid component design with a built-in correction for version reduces excessive stresses in the implant, cement, and glenoid bone. Recommendations for correcting retroversion deformity are asymmetric reaming of the anterior glenoid, bone grafting of the posterior glenoid, or a glenoid component with posterior augmentation. Eccentric reaming has the disadvantages of removing normal bone, reducing structural support for the glenoid component, and increasing the risk of bone perforation by the fixation pegs. Bone grafting to correct retroverted deformity does not consistently generate successful results. Methods: Finite element models of 2 scapulae models representing a normal and an arthritic retroverted glenoid were implanted with a standard glenoid component (in retroversion or neutral alignment) or a wedged component. Glenohumeral forces representing invivo loading were applied and stresses and strains computed in the bone, cement, and glenoid component. Results: The retroverted glenoid components generated the highest compressive stresses and decreased cyclic fatigue life predictions for trabecular bone. Correction of retroversion by the wedged glenoid component significantly decreased stresses and predicted greater bone fatigue life. The cement volume estimated to survive 10 million cycles was the lowest for the retroverted components and the highest for neutrally implanted glenoid components and for wedged components. Conclusion: A wedged glenoid implant is a viable option to correct severe arthritic retroversion, reducing the need for eccentric reaming and the risk for implant failure. © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees.

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