Benjamin E. Bierbaum

Impact of Relational Coordination on Quality of Care, Postoperative Pain and Functioning, and Length of Stay: A Nine-hospital Study of Surgical Patients

BACKGROUND Health care organizations face pressures from patients to improve the quality of care and clinical outcomes, as well as pressures from managed care to do so more efficiently. Coordination, the management of task interdependencies, is one way that health care organizations have attempted to meet these conflicting demands. OBJECTIVES The objectives of this study were to introduce the concept of relational coordination and to determine its impact on the quality of care, postoperative pain and functioning, and the length of stay for patients undergoing an elective surgical procedure. Relational coordination comprises frequent, timely, accurate communication, as well as problem-solving, shared goals, shared knowledge, and mutual respect among health care providers. RESEARCH DESIGN Relational coordination was measured by a cross-sectional questionnaire of health care providers. Quality of care was measured by a cross-sectional postoperative questionnaire of total hip and knee arthroplasty patients. On the same questionnaire, postoperative pain and functioning were measured by the WOMAC osteoarthritis instrument. Length of stay was measured from individual patient hospital records. SUBJECTS The subjects for this study were 338 care providers and 878 patients who completed questionnaires from 9 hospitals in Boston, MA, New York, NY, and Dallas, TX, between July and December 1997. MEASURES Quality of care, postoperative pain and functioning, and length of acute hospital stay. RESULTS Relational coordination varied significantly between sites, ranging from 3.86 to 4.22 (P <0.001). Quality of care was significantly improved by relational coordination (P <0.001) and each of its dimensions. Postoperative pain was significantly reduced by relational coordination (P = 0.041), whereas postoperative functioning was significantly improved by several dimensions of relational coordination, including the frequency of communication (P = 0.044), the strength of shared goals (P = 0.035), and the degree of mutual respect (P = 0.030) among care providers. Length of stay was significantly shortened (53.77%, P <0.001) by relational coordination and each of its dimensions. CONCLUSIONS Relational coordination across health care providers is associated with improved quality of care, reduced postoperative pain, and decreased lengths of hospital stay for patients undergoing total joint arthroplasty. These findings support the design of formal practices to strengthen communication and relationships among key caregivers on surgical units.

A Mouse Model of Human Breast Cancer Metastasis to Human Bone

Currently, an in vivo model of human breast cancer metastasizing from the orthotopic site to bone does not exist, making it difficult to study the many steps of skeletal metastasis. Moreover, models used to identify the mechanisms by which breast cancer metastasizes to bone are limited to intracardiac injection, which seeds the cancer cells directly into the circulation, thus bypassing the early steps in the metastatic process. Such models do not reflect the full process of metastasis occurring in patients. We have developed an animal model of breast cancer metastasis in which the breast cancer cells and the bone target of osteotropic metastasis are both of human origin. The engrafted human bone is functional, based on finding human IgG in the mouse bloodstream, human B cells in the mouse spleen, and normal bone histology. Furthermore, orthotopic injection of a specific human breast cancer cell line, SUM1315 (derived from a metastatic nodule in a patient), later resulted in both bone and lung metastases. In the case of bone, metastasis was to the human implant and not the mouse skeleton, indicating a species-specific osteotropism. This model replicates the events observed in patients with breast cancer skeletal metastases and serves as a useful and relevant model for studying the disease.

Ceramic-on-ceramic bearings in total hip arthroplasty.

The ideal bearing surface for total hip arthroplasty still is being sought. This bearing would be durable, cost-effective, easy to implant, inert, and produce minimal wear debris. Ceramic-on-ceramic bearings have continued to evolve and have enjoyed success in many European centers throughout the past 3 decades. A limited number of early reports from the United States discouraged widespread acceptance and use of ceramic-on-ceramic total hip arthroplasty. Once critically analyzed most of the failures from the early reports are attributable to design and material specific flaws. Vast improvements have been made in ceramic manufacturing leading to even more superior wear characteristics and higher burst strengths. The case for alumina-on-alumina ceramic bearings is becoming stronger as data accumulate clinically and in vitro. In a multicenter, prospective and randomized study, an alumina-on-alumina ceramic bearing is compared with a cobalt chrome-on-polyethylene bearing. After as many as 48 months there has been no significant difference in clinical performance between the two study groups. No ceramic head fracture or ceramic bearing failure has occurred. Therefore, this new alumina-on-alumina ceramic bearing is a safe option for total hip arthroplasty and may provide a more durable prosthesis especially in young and active patients.

Differential expression of GADD45β in normal and osteoarthritic cartilage: Potential role in homeostasis of articular chondrocytes

OBJECTIVE Our previous study suggested that growth arrest and DNA damage-inducible protein 45beta (GADD45beta) prolonged the survival of hypertrophic chondrocytes in the developing mouse embryo. This study was undertaken, therefore, to investigate whether GADD45beta plays a role in adult articular cartilage. METHODS Gene expression profiles of cartilage from patients with late-stage osteoarthritis (OA) were compared with those from patients with early OA and normal controls in 2 separate microarray analyses. Histologic features of cartilage were graded using the Mankin scale, and GADD45beta was localized by immunohistochemistry. Human chondrocytes were transduced with small interfering RNA (siRNA)-GADD45beta or GADD45beta-FLAG. GADD45beta and COL2A1 messenger RNA (mRNA) levels were analyzed by real-time reverse transcriptase-polymerase chain reaction, and promoter activities were analyzed by transient transfection. Cell death was detected by Hoechst 33342 staining of condensed chromatin. RESULTS GADD45beta was expressed at higher levels in cartilage from normal donors and patients with early OA than in cartilage from patients with late-stage OA. All chondrocyte nuclei in normal cartilage immunostained for GADD45beta. In early OA cartilage, GADD45beta was distributed variably in chondrocyte clusters, in middle and deep zone cells, and in osteophytes. In contrast, COL2A1, other collagen genes, and factors associated with skeletal development were up-regulated in late OA, compared with early OA or normal cartilage. In overexpression and knockdown experiments, GADD45beta down-regulated COL2A1 mRNA and promoter activity. NF-kappaB overexpression increased GADD45beta promoter activity, and siRNA-GADD45beta decreased cell survival per se and enhanced tumor necrosis factor alpha-induced cell death in human articular chondrocytes. CONCLUSION These observations suggest that GADD45beta might play an important role in regulating chondrocyte homeostasis by modulating collagen gene expression and promoting cell survival in normal adult cartilage and in early OA.

Bone scanning in the assessment of patellar viability following knee replacement.

In an attempt to diagnose avascular necrosis (AVN) of the patella, a potential complication of the surgical procedure, 99mTc-MDP bone scanning was performed pre- and postoperation in 37 patients treated by 41 total knee arthroplasties. The normal immediate postoperative scan should demonstrate increased radionuclide uptake in the patella when compared to preoperative scans. Decreased uptake was seen in four cases in the early postoperative period. This latter group was believed to be at risk for osteonecrosis and stress fracture of the patella. For this reason, prophylactic restriction of activity was instituted, with subsequent return of normal radionuclide uptake in the patella. Bone scanning provides an effective method of early diagnosis of patients at risk for the development of AVN and secondary patellar fractures following total knee arthroplasty.

The role played by cell-substrate interactions in the pathogenesis of osteoclast-mediated peri-implant osteolysis

Prosthetic wear debris-induced peri-implant osteolysis is a major cause of aseptic loosening after total joint replacement. In this condition, wear particles released from the implant components induce a granulomatous inflammatory reaction at the interface between implant and adjacent bone, leading to progressive bone resorption and loss of fixation. The present study was undertaken to characterize definitively the phenotype of osteoclast-like cells associated with regions of peri-implant focal bone resorption and to compare the phenotypic features of these cells with those of mononucleated and multinucleated cells associated with polyethylene wear particles. Peri-implant tissues were obtained from patients undergoing hip revision surgery for aseptic loosening after total joint replacement. Cells were examined for the expression of several markers associated with the osteoclast phenotype using immunohistochemistry, histochemistry, and/or in situ hybridization. CD68 protein, a marker expressed by multiple macrophage lineage cell types, was detected in mononucleated and multinucleated cells associated with polyethylene particles and the bone surface. Cathepsin K and tartrate-resistant acid phosphatase were expressed highly in both mononucleated and multinucleated cells associated with the bone surface. Levels of expression were much lower in cells associated with polyethylene particles. High levels of β3 integrin protein were detected in cells in contact with bone. Multinucleated cells associated with polyethylene particles exhibited faint positive staining. Calcitonin receptor mRNA expression was detected solely in multinucleated cells present in resorption lacunae on the bone surface and was absent in cells associated with polyethylene particles. Our findings provide further evidence that cells expressing the full repertoire of osteoclast phenotypic markers are involved in the pathogenesis of peri-implant osteolysis after total joint replacement. They also demonstrate that foreign body giant cells, although believed to be phenotypically and functionally distinct from osteoclasts, express many osteoclast-associated genes and gene products. However, the levels and patterns of expression of these genes in the two cell types differ. We speculate that, in addition to the role of cytokines and growth factors, the substrate with which these cells interact plays a critical role in their differential phenotypic and functional properties.

Squeaking in Total Hip Replacement: No Cause for Concern

Traditional total hip arthroplasty (THA) using metalon-polyethylene bearings has been established as a reliable procedure, but polyethylene wear and wear debris–associated osteolysis are among the most frequent reasons for revision.1 Hard-bearing-surface THAs with improved tribological properties have been introduced to decrease wear and wear debris–induced osteolysis. Among the hardbearing alternatives, alumina ceramic-on-ceramic bearings have consistently shown low wear and biological reactivity to wear particles. Clinically, ceramic-on-ceramic hip arthroplasties with modern metal-backed alumina cups have demonstrated excellent clinical outcomes with low revision rates,2,3 with complications such as acetabular liner, femoral head fractures, or chipping occurring rarely.4 Curiously, after more than 30 years of clinical experience with alumina ceramic-on-ceramic bearings worldwide and with 2 closely studied longterm FDA studies in the United States,2,3 a new phenomenon of frequent, clinically reproducible squeaking was reported, primarily beginning in 2006. Further, these reports were authored by surgeons who had little, if any, experience with alumina ceramic-on-ceramic bearings during the IDE study period from 1997 to 2003. Inevitably, many theories were proposed to explain this phenomen, including mismatched ceramic bearings diameters,5 edge loading due to acetabular component malpositioning,6 disruption of fl uid fi lm lubrication with stripe wear,7 microseparation and subluxation of the femoral head,7 the use of short necks,8 and wear debris from metal-on-metal impingement in implants.9 Ultimately though, one fundamental question has remained: Why, after years of successfully using ceramic-on-ceramic THA, did this phenomenon of squeaking suddenly become frequently noted by a subset of surgeons, particularly practicing in the Unitied States? The goal of this study was to use our clinical experience with two FDA IDE studies2,3 during a period of more than 10 years to improve our understanding of this squeaking phenomenon.

Removal and reinsertion of cemented femoral components during acetabular revision.

A retrospective review examined all patients who underwent removal and reinsertion of a cemented femoral component during isolated acetabular revision by one surgeon since 1981. All components were reinserted into the original, intact cement mantle. Forty-two hips with 2- to 10-year follow-up periods were reviewed. Average follow-up period since revision was 67 months. Average followup period since index procedure was 191 months. Average Harris hip score increased from 61 before surgery to 90 at follow-up examination. Two femurs are definitely loose by Harris criteria, but both are asymptomatic. One solidly fixed femoral component was revised because of joint instability. Two hips have postrevision cement fractures. One patient has mild thigh pain. In vitro testing of eight cadaver hips showed no increase in rotational micromotion following removal and reinsertion. It is concluded that this technique aids in isolated acetabular revision surgery by avoiding the complications of trochanteric osteotomy and femoral revision, improving acetabular exposure, and decreasing operative time with minimal risk of disrupting femoral component fixation.

Trochanteric osteotomy: analysis of pattern of wire fixation failure and complications.

Problems and complications following trochanteric osteotomy in 277 total hip replacements demonstrated that while the value of trochanteric osteotomy is obvious, the incidence of problems and complications in 277 total hip replacements was about 15%. Analysis was made of the location and sequence of wire failure following different techniques of trochanteric wiring. The usual method of wire failure was by fatigue fracture, although early fracture in the post-operative phase may be secondary to tensile failure, The incidence of wire tensile failure can be increased by inadvertent kinking or scoring of the wire during trochanteric fixation. An ununited trochanter should be protected against wire failure and its sequelae.

Ceramic-on-Ceramic Hip Outcome at a 5- to 10-Year Interval: Has it Lived Up to Its Expectations?

This study reports revision and complication rates of a single cementless double-wedged tapered stem with an alumina-alumina bearing over 10 years since the beginning of premarket clinical trials. Of 930 hips (848 patients) implanted by 9 surgeons, there were 19 revisions at mean follow-up of 5.9 years compared to 10 revisions in the 123 hips implanted with the polyethylene control group at mean 7.8 years. The ongoing safety of alumina-alumina bearings is demonstrated through excellent (96.8%) survivorship at 10 years. Twenty-one patients reported 23 incidences of noise described as clicking, squeaking, popping, or creaking. Eight patients with 9 hips described the noise as squeaking, most occurring rarely and only 1 occurring frequently in a patient subsequently revised for a reason aside from the squeaking.