Total joint replacement surgeon choice: A qualitative analysis in a medicare population.

INTRODUCTION: Previous research has shown that patients from historically marginalized groups in the United States tend to have poorer outcomes after joint replacement surgery and that they are less likely to receive joint replacement surgery at high-volume hospitals. However, little is known regarding how this group of patients chooses their joint replacement surgeon. The purpose of this study was to understand the factors influencing the choice of joint replacement surgeon amongst a diverse group of patients. METHODS: Semi-structured interviews were conducted with Medicare patients who underwent a hip or knee replacement within the last 24 months (N = 38) at an academic and community hospital. Interviews were audio recorded, transcribed and verified for accuracy. Transcripts were reviewed using iterative content analysis to extract key themes related to how respondents chose their joint replacement surgeon. RESULTS AND DISCUSSION: MD referral/recommendation appears to be the strongest factor influencing joint replacement surgeon choice. Other key considerations are hospital reputation and surgeon attributes-including operative experience, communication skills, and participation in shared decision-making. Gender/ethnicity of a surgeon, industry payments to surgeons, number of publications and cost did not play a large role in surgeon choice. CONCLUSION AND CLINICAL RELEVANCE: The process of choosing a joint replacement surgeon is a complex decision-making process with several factors at play. Despite growing availability of information regarding surgeons, patients largely relied on referrals for choosing their joint replacement surgeon regardless of ethnicity. Referring physicians need to ensure that patients are able to access hospital and surgeon outcomes, operative volume, and industry-payment information to learn more about their orthopedic surgeons in order to make an informed choice.

NELL-1 in the treatment of osteoporotic bone loss.

NELL-1 is a secreted, osteoinductive protein whose expression rheostatically controls skeletal ossification. Overexpression of NELL-1 results in craniosynostosis in humans and mice, whereas lack of Nell-1 expression is associated with skeletal undermineralization. Here we show that Nell-1-haploinsufficient mice have normal skeletal development but undergo age-related osteoporosis, characterized by a reduction in osteoblast:osteoclast (OB:OC) ratio and increased bone fragility. Recombinant NELL-1 binds to integrin ß1 and consequently induces Wnt/ß-catenin signalling, associated with increased OB differentiation and inhibition of OC-directed bone resorption. Systemic delivery of NELL-1 to mice with gonadectomy-induced osteoporosis results in improved bone mineral density. When extended to a large animal model, local delivery of NELL-1 to osteoporotic sheep spine leads to significant increase in bone formation. Altogether, these findings suggest that NELL-1 deficiency plays a role in osteoporosis and demonstrate the potential utility of NELL-1 as a combination anabolic/antiosteoclastic therapeutic for bone loss.

Fixation of non-cemented total hip arthroplasty femoral components in a simulated proximal bone defect model.

An accelerated sequential proximal femoral bone loss model was used to measure the initial stability of three noncemented femoral stem designs: fully porous-coated, proximally porous-coated, and dual-tapered, diaphyseal press-fit (N=18). Only dual-tapered, diaphyseal press-fit stems remained stable with as much as 105 mm of bone loss, with average cyclic micromotion remaining below 25 µm in ML and below 10 µm in AP planes. In contrast, with proximally coated and fully coated stem designs with circular or oval cross-sections, 60mm of bone loss, resulting in lower than 10 cm of diaphyseal bone contact length, led to gross instability, increasing average cyclic micromotions to greater than 100 µm prior to failure. Therefore, the results provide support for using a dual-tapered stem in revision cases with proximal bone loss.

Effect of proximal femoral bone support on the fixation of a press-fit noncemented total hip replacement femoral component.

PURPOSE: Proximal femoral bone loss is a common challenge in revision hip arthroplasty. In this study, in-vitro fixation of a non-cemented, rectangular, dual-tapered, press-fit femoral component designed to achieve metadiaphyseal fixation was analyzed using an accelerated proximal femoral bone loss model to assess the potential use in revision cases. METHODS: The press-fit AlloclassicTM femoral stem was implanted in ten cadaveric femurs and tested under cyclic biomechanical loading in an intact state, and then again after sequential proximal femoral bone resections, simulating increasing amounts of bone deficiency. Anterior-posterior and medial-lateral interface motions were measured at the distal stem tip throughout loading. 
 RESULTS: Three specimens remained stable throughout testing, with initial and peak per-cycle motions of less than 50 µm. Six specimens were destabilized under loading with higher per-cycle motions, specifically at the distal stem tip during peak loading in the anterior-posterior direction, with motions of 78±69 µm, compared to 12±9 µm in the stable specimens (P<.05). Total migration of the destabilized specimens was also significantly higher, specifically at the proximal stem tip in the medial-lateral direction, with migrations of 101±34 µm (P<.05) and at the distal stem tip in the anterior-posterior direction, with migrations of 155±179 µm (P<.05), compared to 33±12 µm and 13±11 µm for the stable specimens. CONCLUSION: The results indicate that when strong initial fixation is achieved, long-term success is possible given substantial proximal femoral bone loss.

Active Referral Intervention following Fragility Fractures Leads to Enhanced Osteoporosis Follow-Up Care.

At one major urban academic medical center, patients aged 50 years and older with fragility fractures were identified and scheduled or assisted in referral into osteoporosis medical management appointments. We evaluated the efficacy of an active intervention program at overcoming the logistical barriers and improving proper osteoporosis follow-up for persons who have sustained a fragility fracture. Of 681 patients treated for defined fractures, 168 were eligible and consented for the study of fragility fractures. Of those enrolled, 91 (54.2%) had appropriate osteoporosis follow-up on initial interview, and overall 120 (71.4%) had successful osteoporosis follow-up following our active intervention. Seventy patients (41.7%) were deemed to have no osteoporosis follow-up, and, of these, 48 were successfully referred to a scheduling coordinator. The scheduling coordinator was able to contact 37 (77%) patients to schedule proper follow-up, and, of these, 29 (78.4%) confirmed receiving an appropriate follow-up appointment. Active intervention and assisted scheduling for patients with recent fragility fractures improved the self-reported rate of osteoporosis follow-up from 54.2% to 71.4%.

Hip resurfacing as treatment for synovial chondromatosis.

Synovial chondromatosis is a rare condition of metaplastic cartilage development in the synovial membrane of joints. These foci can form free bodies and lead to mechanical arthrosis. The precise etiology is unknown. All synovial joints can be affected, with the hip and knee being most common. Patients with synovial chondromatosis are usually in their fifth decade and typically present with mechanical pain and diffuse swelling. Due to its rarity and nonspecific manifestations, diagnosis of synovial chondromatosis is often delayed until significant mechanical damage and arthrosis has occurred.Controversy exists regarding surgical treatment of synovial chondromatosis, especially with regard to the hip. Localized disease can be treated with resection of affected synovium (possibly arthroscopically), whereas patients with generalized disease require complete, open synovectomy. With articular damage, total hip replacement has been advocated along with synovectomy.This article presents a case of a young man with painful hip synovial chondromatosis who was successfully treated with hip resurfacing and synovectomy after failed hip arthroscopy. Hip resurfacing provides the surgeon with the opportunity to address not only local or generalized synovial disease, but articular damage as well. Furthermore, its bone-preserving properties make this option attractive in the management of this younger patient population. We feel resurfacing has a role in the surgical treatment of synovial chondromatosis. To our knowledge, this is the first case of hip resurfacing arthroplasty for the definitive treatment of synovial chondromatosis.

Less range of motion with resurfacing arthroplasty than with total hip arthroplasty: in vitro examination of 8 designs.

BACKGROUND AND PURPOSE: Hip resurfacing arthroplasty has had resurgence recently and is now a popular option for younger, active patients. We used an in vitro model to assess range of motion and impingement profile for hip resurfacing and compared them to those for conventional total hip arthroplasty. METHODS: 8 different hip replacement designs were implanted into adult composite femurs and pelvises. These were mounted onto a 3-dimensional compass allowing all motions, with the degrees and impingement recorded. The designs tested were the Conserve Plus Hip Resurfacing System, Depuy ASR, Birmingham Hip Resurfacing System, Charnley, McKee-Farrar metal-on-metal, SROM Hip metal-on-metal, SROM Hip metal-on-polyethylene, Prodigy metal-on-metal, and also a native intact composite femur and pelvic articulation. Femoral stems were tested at 0 and 20 degrees of anteversion. RESULTS: Conventional hip arthroplasty exhibited statistically significantly greater range of motion than resurfacing arthroplasty. Resurfacing showed neck impingement in 29/30 motions. Conventional arthroplasties showed femoral neck impingement in 41/100 motions. INTERPRETATION: In situ range of motion of resurfacing arthroplasty was less than that of conventional total hip arthroplasty. Resurfacing systems impinged almost entirely on the femoral neck, while conventional hip arthroplasties had a varied impingement profile. Our findings raise concern for early neck-on-cup impingement, which may cause component loosening and femoral neck fracture, both of which are observed after hip resurfacing.

The effect of patellar thickness on intraoperative knee flexion and patellar tracking in total knee arthroplasty.

We designed a simple IRB-approved study to evaluate the intraoperative effect of patellar thickness on knee flexion and patellar tracking during total knee arthroplasty. Routine PCL-retaining total knee arthroplasty was performed in 31 consecutive knees. With clinical balance and congruent patella tracking established, custom trial patellar components that were thicker than the standard trial by 2-mm increments (2-8 mm) were sequentially placed and trialed. Passive flexion was recorded to the nearest 5 degrees with an intraoperative goniometer and gross mechanics of patellofemoral tracking were visually assessed. On average, passive knee flexion decreased 3 degrees for every 2-mm increment of patellar thickness. Furthermore, for the knee system used in this study, increased patellar thickness had no gross effect on patellar subluxation or tilt.

The effect of distal femoral resection on passive knee extension in posterior cruciate ligament-retaining total knee arthroplasty.

Full passive extension in total knee arthroplasty is predicated on creating a large enough extension gap to accommodate any given combined thickness of femoral and tibial components. Additional distal femoral resection can achieve more passive knee extension. The predictable effect of further distal femoral resection has never been studied. We designed a simple institutional review board-approved, intraoperative study to quantify this effect. Routine posterior cruciate ligament-preserving total knee arthroplasty was performed with measured femoral and tibial resections, yielding full passive extension with trial components. Distal femoral augments were then sequentially applied to the back of the femoral trial component, and passive knee extension was measured. The data show that an average value of 9 degrees of femoral contracture is corrected for every 2 mm of distal femoral resection.

Using tandem scanning confocal microscopy to predict the status of donor kidneys.

Tandem scanning confocal microscopy (TSCM) is a noninvasive form of vital microscopy that can be used to evaluate superficial uriniferous tubules in living kidneys. Because TSCM has a number of advantages over conventional microscopic examination of renal biopsies, the present study was undertaken to determine whether the histopathological images obtained by TSCM correlate with post-transplant renal function. The kidneys of New Zealand male rabbits were harvested, flushed with Euro-Collins solution, and stored at 0-2 degrees C for periods of 24, 48, 67 and 72 h prior to transplantation. TSCM observation of the kidneys prior to their transplantation revealed characteristic histopathological changes of the superficial proximal convoluted tubules that correlated closely with subsequent post-transplant renal function. These observations indicate that TSCM may be of significant value in evaluating the status of donor kidneys prior to their transplantation.