Faculty Bibliography

INTRODUCTION: Increasing hip fracture incidence in the United States is leading to higher occurrences of conversion total hip arthroplasty (THA) for failed surgical treatment of the hip. In spite of studies showing higher complication rates in conversion THA, the Centers for Medicare and Medicaid services currently bundles conversion and primary THA under the same diagnosis-related group. We examined the cost of treatment of conversion THA compared with primary THA. Our hypothesis is that conversion THA will have higher cost and resource use than primary THA. METHODS: Fifty-one consecutive conversion THA patients (Current Procedure Terminology code 27132) and 105 matched primary THA patients (Current Procedure Terminology code 27130) were included in this study. The natural log-transformed costs for conversion and primary THA were compared using regression analysis. Age, gender, body mass index, American Society of Anesthesiologist, Charlson comorbidity score, and smoker status were controlled in the analysis. Conversion THA subgroups formed based on etiology were compared using analysis of variance analysis. RESULTS: Conversion and primary THAs were determined to be significantly different (P<.05) and greater in the following costs: hospital operating direct cost (29.2% greater), hospital operating total cost (28.8% greater), direct hospital cost (24.7% greater), and total hospital cost (26.4% greater). CONCLUSIONS: Based on greater hospital operating direct cost, hospital operating total cost, direct hospital cost, and total hospital cost, conversion THA has significantly greater cost and resource use than primary THA. In order to prevent disincentives for treating these complex surgical patients, reclassification of conversion THA is needed, as they do not fit together with primary THA.

OBJECTIVES: To create and evaluate normalized T1rho profiles of the entire femoral cartilage in healthy subjects with three-dimensional (3D) angle- and depth-dependent analysis. METHODS: T1rho images of the knee from 20 healthy volunteers were acquired on a 3.0-T unit. Cartilage segmentation of the entire femur was performed slice-by-slice by a board-certified radiologist. The T1rho depth/angle-dependent profile was investigated by partitioning cartilage into superficial and deep layers, and angular segmentation in increments of 4 degrees over the length of segmented cartilage. Average T1rho values were calculated with normalized T1rho profiles. Surface maps and 3D graphs were created. RESULTS: T1rho profiles have regional and depth variations, with no significant magic angle effect. Average T1rho values in the superficial layer of the femoral cartilage were higher than those in the deep layer in most locations (p < 0.05). T1rho values in the deep layer of the weight-bearing portions of the medial and lateral condyles were lower than those of the corresponding non-weight-bearing portions (p < 0.05). Surface maps and 3D graphs demonstrated that cartilage T1rho values were not homogeneous over the entire femur. CONCLUSIONS: Normalized T1rho profiles from the entire femoral cartilage will be useful for diagnosing local or early T1rho abnormalities and osteoarthritis in clinical applications. KEY POINTS: * T1rho profiles are not homogeneous over the entire femur. * There is angle- and depth-dependent variation in T1rho profiles. * There is no influence of magic angle effect on T1rho profiles. * Maps/graphs might be useful if several difficulties are solved.

BACKGROUND: Preoperative anemia is present in 20% of total joint arthroplasty patients. Current preoperative treatment options, including iron supplementation (FE) and erythropoietin (EPO), are expensive. Tranexamic acid (TXA) has been adopted as an intraoperative adjunct to decrease blood loss. Our hypothesis is that TXA is a cost-effective treatment compared to FE and EPO in anemic patients. METHODS: In this study, a cost analysis was performed, comparing the material costs of TXA and packed red blood cells (PRBCs) to the theoretical administration and material costs of FE and EPO per standard preoperative anemia protocol. RESULTS: A total of 243 patients were included in the study. Of this group, 18.5% (45/243) had preoperative anemia. The rate of transfusion was 6.7% (3/45), and 5 units of PRBCs was transfused. The combined cost of TXA and PRBCs was $5317.08. Even assuming a best-case scenario with FE or EPO treatment without a postoperative PRBC requirement, the cost of treatment would range from 2 to 17 times more than treatment with TXA. An additional 50 units of PRBC (1.1 units per patient) would need to be transfused for the cost of TXA treatment to be equivalent to FE or EPO treatment. CONCLUSION: Tranexamic acid is significantly less expensive than FE or EPO as a treatment option for total joint arthroplasty patients presenting with preoperative anemia. It is a cost-effective adjunct for limiting transfusion rates in this patient population. We recommend that new preoperative anemia levels that necessitate preoperative intervention be established.

In this study, we compare patients' risk-taking and spending behaviors to their willingness to pay (WTP) for novel implants in a joint arthroplasty. 210 patients were surveyed regarding risk-taking and spending behavior, and WTP for novel implants with either increased-longevity, increased-longevity with higher risk of complications, or decreased risk of complications compared to a standard implant. Patients with increased recreational risk-taking behavior were more WTP for increased-longevity. Patients who "rarely" take health-risks were more WTP for decreased risk of complications. Patients with higher combined risk scores were more WTP for all novel implants. Patients who paid more than $50,000 for their current car were more WTP for decreased complications. This study shows that patients' risk taking and spending behavior influences their WTP for novel implants.

Achondroplasia (ACH) is the most common form of hereditary dwarfism and presents with multiple musculoskeletal anomalies but is not normally associated with premature hip arthritis. Developmental dysplasia of the hip (DDH) is a spectrum of disease resulting in shallow acetabular depth and a propensity for chronic femoral subluxation or dislocation; it is among the most common causes of premature arthritis. This case report describes the diagnosis of symptomatic DDH in a patient with ACH and highlights difficulties of primary total hip arthroplasty (THA) as a treatment option. Intraoperative radiographic imaging is advised to ensure proper prosthesis placement. Femoral osteotomy may aid visualization, reduction, and avoidance of soft tissue injury. Concomitant ACH and DDH is a challenging problem that can be successfully treated with modified THA.

INTRODUCTION: Metallosis occurs when periprosthetic soft tissues, synovium, and/or bone is infiltrated by metallic debris secondary to metal-on-metal wear. This debris can cause a chronic inflammatory reaction leading to joint instability, pain, and swelling, and may cause osteolysis, implant looseningand ultimately implant failure. CASE REPORT: An 81 year old female, with a history of primary left total knee arthroplasty, presented with a 6 month history of left knee pain, swelling, and limited range of motion following a fall. Radiographs and joint aspiration were performed, with results that showed no evidence of periprosthetic trauma or infection but were suspicious for chronic metallosis. The patient underwent revision total knee replacement of the left knee which revealed extensive necrotic black metal debris throughout the joint space. Histopathology confirmed the diagnosis of a foreign body reaction consistent with metallosis. CONCLUSION: This case is a rare example of chronic metallosis presenting 26 years following total knee replacement. Treatment with revision total knee replacement is the consensus management choice to avoid further destruction of the bone and joint capsule that can occur with metal-induced inflammation.

Local infiltration anesthesia (LIA) with anesthetics, steroids, NSAIDS, and epinephrine has been shown to be effective in reducing total knee arthroplasty (TKA) postoperative pain. This systematic review explores the functional outcomes of randomized control trials that have compared the use of LIA with and without steroids during TKA. Five studies with 412 patients met the inclusion criteria, 228 received local infiltration anesthesia with steroids (LIAS) and 184 received local infiltration anesthesia without steroids (LIAWS). The use of LIAS in management of postoperative TKA pain has been shown to decrease the length of hospital stay, time required to achieve straight leg raise, and pro-inflammatory signals in patients. Although there is no overwhelming data to suggest LIAS improves postoperative TKA pain, current literature does support its effectiveness in producing other favorable surgical outcomes.

BACKGROUND: Total knee arthroplasty (TKA) instrumentation and implant designs have been evolving, with one of the current innovations being patient-specific implants (PSIs). PURPOSE: To evaluate whether there is a significant difference in surgical time, intraoperative blood loss, postoperative range of motion, and length of stay between PSI and conventional TKA. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A consecutive series of 621 TKA patients, 307 with PSIs and 314 with conventional implants, was reviewed. Differences in estimated blood loss, length of stay, range of motion, and surgical time/tourniquet time between the 2 cohorts were analyzed. RESULTS: Linear regression analysis demonstrated that PSI decreased estimated blood loss by 44.72 mL (P < .01), decreased length of stay by 0.39 days (P < .01), decreased postoperative range of motion by 3.90 degrees (P < .01), and had a negligible difference on surgical and tourniquet time. CONCLUSION: The use of PSI is associated with decreased estimated blood loss, decreased length of stay, decreased range of motion, and no discernible difference in surgical or tourniquet time, all of which are unlikely to be clinically significant.

The purpose of this paper is to review the clinical indications for acetabular reconstruction in patients with underlying peri-prosthetic segmental and cavitary defects, evaluate steps in pre-operative planning, and present the American Academy of Orthopaedic Surgeons (AAOS) and Paprosky classification systems to categorize acetabular defects. We also present a review of the current surgical techniques to reconstruct the acetabular socket which includes a cementless acetabular component with morselized bone, structural allograft, jumbo and oblong cups, reinforcement rings, bone cages, custom triflange acetabular constructs, and trabecular metal components.

The treatment of knee osteoarthritis and the preparation for total knee arthroplasty require repetitive imaging to guide preoperative planning and operative technique. Full-length standing anteroposterior images are the gold standard in assessing the alignment of the limb via the measurement of the mechanical axis of the knee. The anatomical axis can be obtained from a more limited image of the knee, and as such is less expensive and exposes the patient to less ionizing radiation. The objective of this cross-sectional prospective study was to examine the extent to which the anatomical axis measured on a fixed-flexed posteroanterior (Rosenberg view) radiograph correlates with the mechanical axis. The data of 209 total knee arthroplasty radiographs were analyzed to compare the preoperative correlation between the mechanical and anatomical axis. The anatomical axis correlated with the mechanical axis when it was measured from both the standing full-length anteroposterior radiograph and from a fixed-flexed posteroanterior radiograph. Using an angle of offset found from linear regression, these correlations become closer. Body mass index and Kellgren-Lawrence grade were not found to have a significant effect. It is the conclusion of this study that the anatomical axis, as measured from a limited knee radiography, may serve as a plausible estimate of the mechanical axis when done with a neutral angle of offset, and that offset angle depends on gender and the imaging technique used to determine the anatomical axis. [Orthopedics. 2015; 38(12):e1115-e1120.].