Failure Following Revision Total Hip Arthroplasty After Cobalt-Chrome Femoral Heads are Placed on a Retained Femoral Stem.

BACKGROUND: Failure due to trunnionosis with adverse local tissue reaction (ALTR) has been reported with cobalt-chrome (CoCr) heads in total hip arthroplasty (THA); however, there are limited data on the use of these heads in the revision setting. The purpose of this study was to analyze the outcomes of patients who underwent revision THA with a retained femoral component and received a CoCr femoral head on a used trunnion. METHODS: In this retrospective review, we identified all patients who underwent revision THA with a retained femoral component and received a CoCr femoral head between February 2006 and March 2014. Demographic factors, implant details, and postoperative complications, including the need for repeat revisions, were recorded. In total, 107 patients were included (mean age 67 years, 74.0% women). Of the 107 patients, 24 (22.4%) required repeat revisions. RESULTS: Patients who required repeat revision were younger than those who did not (mean age: 62.9 versus 69, P = .03). The most common indications for repeat revision were instability (8 of 24, 33.3%), ALTR (5 of 24, 20.8%), and infection (4 of 18, 16.7%). Evidence of ALTR or metallosis was identified at the time of reoperation in 10 of the 24 patients who underwent re-revision (41.7%). CONCLUSIONS: The placement of a new CoCr femoral head on a used trunnion during revision THA with a retained femoral component carries a significant risk of complication (22.4%) and should be avoided when possible.

Financial Burden of Revision Hip and Knee Arthroplasty at an Orthopedic Specialty Hospital: Higher Costs and Unequal Reimbursements.

BACKGROUND: As demand for primary total joint arthroplasty (TJA) continues to grow, a proportionate increase in revision TJA (rTJA) is expected. It is essential to understand costs and reimbursement of rTJA as our country moves to bundled payment models. We aimed (1) to characterize implant and total hospital costs, (2) assess reimbursement, and (3) determine revenue for rTJA in comparison with primary TJA. METHODS: The average implant and total hospital cost of all primary and rTJA procedures by diagnosis-related group (DRG) was calculated using time-driven activity-based costing at an orthopedic hospital from 2018 to 2020. Average reimbursement and payer type were assessed by DRG. Revenue was calculated by deducting average time-driven activity-based costing total costs from reimbursement. RESULTS: 13,946 arthroplasties were included in the study. Implant cost comprised 55.8% of total hospital costs for rTJA DRG 468, compared with 43.6% of total hospital costs for primary TJA DRG 470. Total hospital costs for DRG 468 were 61.1% more than DRG 470. Reimbursement for rTJA was 1.23x more than primary TJA. Private payers paid 23.2% more than Medicare for rTJA. Margin for DRG 468 was 1.5% less than primary DRG 470. CONCLUSION: rTJA requires more hospital resources and costs than primaries, yet hospital reimbursement may be inadequate with the additional expenditures necessary to provide optimal care. If hospitals cannot perform revision services under the current reimbursement model, patient access may be limited. Implant costs are a major contributor to overall rTJA cost. Strategies are needed to reduce revision implant costs to improve value of care. LEVEL OF EVIDENCE: Level III, economic and decision analysis.

Effect of Pelvic Tilt and Rotation on Cup Orientation in Both Supine and Standing Positions.

BACKGROUND: The purpose of this study is to analyze the effect of pelvic tilt and rotation on radiographic measurement of cup orientation. METHODS: A total of 68 patients (79 hips) were included in this study. The patients had a computed tomography study and approximately 3 months of postoperative standing anteroposterior pelvic radiographs in both supine and standing positions. We used 2-dimensional (2D)/3-dimensional (3D) matching to measure pelvic tilt and rotation, and cup orientation. RESULTS: There was a wide range of pelvic tilt between individuals in both supine and standing positions. Supine pelvic tilt was different from standing pelvic tilt (P < .05). There were differences in cup anteversion before and after 2D/3D matching in both supine and standing positions (P < .05). Supine and standing pelvic tilt correlated with differences in cup anteversion before and after 2D/3D matching. When all 79 hips were separated into right and left side, pelvic rotation inversely correlated with the pelvic tilt-adjusted difference in anteversion before and after 2D/3D matching of the right side but directly correlated with that of the left side in both supine and standing positions. CONCLUSION: This study demonstrated that the measurement of cup anteversion on anteroposterior radiographs is significantly affected by both pelvic tilt and pelvic rotation (depending on the side). Improved understanding of pelvic orientation and improved ability to measure pelvic orientation may eventually allow for desired cup positioning to potentially protect against complications associated with malposition of the cup.

Low dose compared to variable dose Warfarin and to Fondaparinux as prophylaxis for thromboembolism after elective hip or knee replacement surgery; a randomized, prospective study.

BACKGROUND: Deep vein thrombosis (DVT) and pulmonary emboli (PE), known together as venous thromboembolic (VTE) disease remain major complications following elective hip and knee surgery. This study compares three chemoprophylactic regimens for VTE following elective primary unilateral hip or knee replacement, one of which was designed to minimize risk of post-operative bleeding. METHODS: Patients were randomized and stratified for hip vs. knee to receive A: variable dose warfarin (first dose on the night preceding surgery with subsequent target INR 2.0-2.5), B: 2.5 mg fondaparinux daily starting 6-18 h postoperatively, or C: fixed 1.0 mg dose warfarin daily starting 7 days preoperatively. All treatments continued until bilateral leg venous ultrasound day 28 ± 2 or earlier upon a VTE event. The study examined primary endpoints including leg DVT, PE or death due to VTE and secondary endpoints including effects on D-dimer, estimated blood loss (EBL) at surgery and hemorrhagic complications. RESULTS: Three hundred fifty-five patients were randomized. None was lost to follow-up. Taking 1.0 mg warfarin for seven days preoperatively did not prolong the prothrombin time (PT). Two patients in Arm C had asymptomatic distal DVT. One major bleed occurred in Arm B and one in Arm C (ischemic colitis). Elevated d-dimer did not predict delayed VTE for one year. CONCLUSIONS: Fixed low dose warfarin started preoperatively is equivalent to two other standards of care under study (95 % CI: -0.0428, 0.0067 for both) as VTE prophylaxis for the patients having elective major joint replacement surgery. TRIAL REGISTRATION: ClinicalTrials.gov identifier # NCT00767559 FDA IND: 103,716.

Corrosion and Adverse Local Tissue Reaction in One Type of Modular Neck Stem.

Modular neck stems allow for optimization of joint biomechanics by restoring anteversion, offset, and limb length. A potential disadvantage is the generation of metal ions from fretting and crevice corrosion. We identified 118 total hip arthroplasty implanted with one type of dual-modular femoral component. Thirty-six required revision due to adverse local tissue reaction. Multivariate analysis isolated females and low offset necks as risk factors for failure. Kaplan-Meir analysis revealed small stem sizes failed at a higher rate during early follow-up period. Although the cobalt/chrome levels were higher in the failed group, these tests had low diagnostic accuracy for ALTR, while MRI scan was more sensitive. We conclude that the complications related to the use of dual modular stems of this design outweigh the potential benefits.

Adverse tissue reactions in modular exchangeable neck implants: a report of two cases.

Dual-modular femoral stems with exchangeable necks theoretically allow optimization of hip joint biomechanics via selective restoration of femoral anteversion, offset, and limb length. A potential disadvantage is the possible generation of metal ions and debris by fretting and crevice corrosion at the additional stem-neck interface. We present 2 cases of early-onset adverse inflammatory tissue reactions as a result of accelerated corrosion at the stem-neck interface of a dual-modular implant, requiring subsequent revision of well-fixed components.

Revision of a dual-modular stem in patients with adverse tissue reaction.

BACKGROUND: Dual-modular femoral components with exchangeable cobalt-chrome neck segments have had higher than expected failure rates due to corrosion and adverse local tissue reaction (ALTR). Complications, survival rates and early clinical outcomes of revision surgery for the treatment of corrosion and ALTR as a result of these implants are underreported. METHODS: We identified 44 cases of revision THA for corrosion and ALTR resulting from the same dual modular stem. All revision procedures were performed using a modular tapered fluted titanium stem, ceramic heads and highly cross-linked polyethylene. RESULTS: Complications included: dislocation, infection, reoperation, and chronic pain. Mean Harris Hip Score was 84 following revision surgery. CONCLUSIONS: Patients undergoing revision surgery for ALTR related to this prosthesis should be aware of the risk of postoperative dislocation and other complications and the potential long-term risk of some chronic pain.

Effect of pelvic tilt and rotation on cup orientation in standing anteroposterior radiographs.

BACKGROUND: Individual pelvic tilt and rotation have wide variability that can affect the measurement of cup orientation in anteroposterior (AP) radiographs. The purpose of this study was to analyse the effect of pelvic tilt and rotation on radiographic measurements of cup orientation. METHODS: A total of 53 patients (63 hips) were included in this study. The patients underwent a computed tomography study with standing AP pelvis radiographs taken both preoperatively and approximately 3 months postoperatively. We used 2-dimensional/3-dimensional matching to measure the pelvic tilt and rotation, and the non-standardised and standardised cup orientation. RESULTS: There was no difference in the pelvic tilt and rotation between the preoperative and postoperative radiographs. The distribution of the differences between the non-standardised and standardised cup anteversion exhibited a change within 5° in only 34/63 (54%) hips. The pelvic tilt correlated with the difference between the non-standardised and standardised cup anteversion, but the pelvic rotation did not. When all 63 hips were separated into the right and left sides, the pelvic rotation inversely correlated with the pelvic tilt-adjusted difference between the non-standardised and standardised cup anteversion of the right side but directly correlated with that of the left side. CONCLUSIONS: The current study demonstrated that the measurement of cup anteversion in standing AP radiographs is significantly affected by both the pelvic tilt and pelvic rotation. An improved understanding of the pelvic orientation may eventually allow for desired cup positioning on a patient-specific basis to potentially reduce complications associated with the malposition of the cup.

Trends in surgical management of femoral neck fractures in the United States.

UNLABELLED: We examined trends in utilization of open reduction and internal fixation (ORIF), THA, and hemiarthroplasty (HA) for femoral neck fractures. Closed femoral neck fractures managed with ORIF or hip arthroplasty (n = 162,257) were extracted from 1990 to 2001 Nationwide Inpatient Samples. Trends were examined during three periods (1990-1993 [Period I], 1994-1997 [Period II], and 1998-2001 [Period III]). Utilization of HA increased from 67.8% in Period I to 75.3% in Period III. In the same period, utilization of THA decreased from 11.6% to 6.6%. The trend of decreased use of THA was consistent regardless of age, hospital, or surgeon volume. In Period III, 28.7% of patients were managed at urban teaching hospitals as compared with 19.6% in Period I. Increased utilization of HA conforms with recent evidence that arthroplasty has better outcomes than ORIF. However, the decrease in THA is contrary to what was expected, and its impact on patient outcomes needs to be evaluated. The increase in the proportion of femoral fractures managed at urban teaching hospitals may reflect a change in the organization of trauma systems during the last decade. LEVEL OF EVIDENCE: Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Management and Prevention of Intraoperative Acetabular Fracture in Primary Total Hip Arthroplasty.

Intraoperative acetabular fracture (IAF) is a rare complication of primary total hip arthroplasty (THA). Known risk factors include poor bone stock, underreaming of the acetabular bed, and use of elliptic components. There is a paucity of literature on risk factors, treatment strategies, and outcomes of this potentially devastating complication. We studied the incidence of IAF in primary THA at our high-volume institution. We reviewed 21,519 primary THA cases and identified 16 patients (16 hips) with IAFs. Mean follow-up was 4 years (range, 0-10 years). Implant data were recorded, and acetabular components were identified as elliptic modular or hemispheric modular. The institution's IAF rate was 0.0007%. All IAFs were associated with uncemented acetabular components. Sixty-nine percent of the fractures were not appreciated during surgery. All posterior column fractures required operative intervention in the immediate or early (<3 months) postoperative period. Compared with anterior column fractures, posterior column fractures were associated with acetabular component instability and need for additional surgery. In this article, we also present strategies for managing and preventing IAF in primary THA. This rare fracture requires prompt recognition and often necessitates aggressive management. More study is needed to determine how to better manage IAFs.

Implantable electrical stimulation in high-risk hindfoot fusions.

The risk of nonunion in both the ankle and subtalar joints has been reported as high as 41% and 16%, respectively. Several factors have been reported to significantly increase the incidence of nonunion: smoking, previous nonunion, osteonecrosis, history of infection, fracture type, and major medical problems. A single surgeon's experience is retrospectively reviewed. Thirteen patients who were identified as high risk for non-union had an implantable electrical stimulator placed at the time of their ankle or hindfoot fusion along with bone grafting. Three ankle, two subtalar, six tibiotalocalcaneal, and two tibiocalcaneal fusions were performed. All 13 patients had a minimum of two major risk factors for non-union. Of the 13 patients, 11 were active smokers and five of 13 had three or more major risk factors. At a minimum of one year follow-up (average, 24.6 months), successful fusion was achieved in 12 of 13 (92%) patients. Pain scores improved from a mean of 8.5 points preoperatively (range, 7 to 10) to a mean of 1.9 points postoperatively (range, 1 to 6), while the preoperative mean modified AOFAS score of 31.2 points (range, 15 to 55) improved to 85.4 points (range, 45 to 100) postoperatively. The improvement was statistically significant at p<0.01. Eleven of 13 patients (85%) ranked their pain as a 1 or 2 out of 10, and achieved a modified AOFAS score of 80 or better. No additional procedures were done to achieve fusion. Four patients developed superficial wound infections requiring local wound care. The subcutaneous battery pack was bothersome to eight of 13 patients, painful to one, and removed in four patients. The results suggest that electrical implantable stimulation may be a useful adjunct to rigid internal fixation and bone grafting for ankle and hindfoot fusions in high-risk patients.

Spontaneous modular femoral head dissociation complicating total hip arthroplasty.

Modular femoral heads have been used successfully for many years in total hip arthroplasty. Few complications have been reported for the modular Morse taper connection between the femoral head and trunnion of the stem in metal-on-polyethylene bearings. Although there has always been some concern over the potential for fretting, corrosion, and generation of particulate debris at the modular junction, this was not considered a significant clinical problem. More recently, concern has increased because fretting and corrosive debris have resulted in rare cases of pain, adverse local tissue reaction, pseudotumor, and osteolysis. Larger femoral heads, which have gained popularity in total hip arthroplasty, are suspected to increase the potential for local and systemic complications of fretting, corrosion, and generation of metal ions because of greater torque at the modular junction. A less common complication is dissociation of the modular femoral heads. Morse taper dissociation has been reported in the literature, mainly in association with a traumatic event, such as closed reduction of a dislocation or fatigue fracture of the femoral neck of a prosthesis. This report describes 3 cases of spontaneous dissociation of the modular prosthetic femoral head from the trunnion of the same tapered titanium stem because of fretting and wear of the Morse taper in a metal-on-polyethylene bearing. Continued clinical and scientific research on Morse taper junctions is warranted to identify and prioritize implant and surgical factors that lead to this and other types of trunnion failure to minimize complications associated with Morse taper junctions as hip implants and surgical techniques continue to evolve.

A multidisciplinary total hip arthroplasty protocol with accelerated postoperative rehabilitation: does the patient benefit?

Since its debut over 10 years ago, minimally invasive total hip arthroplasty (THA) has often been associated with accelerated postoperative rehabilitation when compared with THA performed with a traditional surgical approach. The objective of this study was to investigate the effect of accelerated postoperative rehabilitation and early mobilization on length of stay and hospital readmissions in patients undergoing THA at one institution. We retrospectively reviewed a consecutive series of 590 patients who underwent THA between January 31, 2011 and April 30, 2011. Six arthroplasty surgeons using varying surgical techniques participated. One hundred ninety patients received accelerated rehabilitation and were mobilized on the day of surgery. The remaining 400 patients were mobilized on postoperative day one (POD1). Length of stay for the accelerated rehabilitation group was 2.06 days and 3.38 days for the standard group. One patient was readmitted to the hospital within 30 days (.52%) in the accelerated group compared to 19 re-hospitalizations (4.72%) in the POD1 group. Ninety-six percent of the accelerated group were discharged home versus 62% in POD1 group. Our results support the use of an accelerated rehabilitation protocol at one institution following total hip replacement surgery.

Effect of preoperative exercise on postoperative mobility in obese total joint replacement patients.

There has been a significant increase in obesity in the United States over the past 20 years. Reports in the literature identify the association of obesity-related osteoarthritis and the likelihood of future total hip arthroplasty (THA) and total knee arthroplasty (TKA) in this patient population. However, little is known about the effect of preoperative exercise on immediate postoperative mobility and discharge disposition in obese total joint replacement patients. The purpose of this study was to examine the effect of preoperative exercise in the obese total joint replacement patient on early postoperative mobility and discharge disposition. We retrospectively reviewed a consecutive series of patients with a body mass index (BMI) ≥30 kg/m(2) who underwent primary total joint replacement surgery from June 2005 through October 2005 at 1 institution. Two hundred seven patients met the inclusion criteria. Sixty-five patients performed self-reported preoperative exercise, defined as physical activity deemed above and beyond that of activities of daily living. Fewer exercise patients, 6.8%, required the assistance of ≥2 caregivers for mobility on postoperative day 1 vs 17.4% for nonexercisers. Fifty-four percent of patients participating in preoperative exercise were discharged home vs 46% who did not participate in exercise. A preoperative exercise program can improve postoperative functional mobility and increase the likelihood of discharge home in total joint replacement patients with a BMI of ≥30 kg/m(2).

Use of a hydroxyapatite-coated stem in patients with Dorr Type C femoral bone.

Type C bone, as described by Dorr, exhibits both cellular and structural compromise, which presents a challenge for fixation of a total hip arthroplasty (THA). We evaluated the performance of the Omnifit HA stem, a hydroxyapatite-coated titanium alloy stem, by retrospectively reviewing the clinical and radiographic data of 15 patients with femoral Type C bone who received the stem during primary THA between 1991 and 1994. The patients were followed a minimum of 9 years (mean, 11.5 years; range, 9-14 years). The average age at surgery was 54 years and the average body mass index was 28. Eight of the patients were men. The median Harris hip score was 94.5 points. Radiographically, two independent reviewers identified all patients as Type C bone. The average canal to calcar isthmus ratio was 0.74 (range, 0.65-0.95). At most recent followup, four patients demonstrated proximal osteolysis. Using plain radiography we detected no patients with distal osteolysis or subsidence. At 9 to 14 years, the stem has performed well in a selected series of patients with poor bone quality and the outcomes compare favorably with previously reported findings using this design of stem in other bone types. These results support the decision to use a hydroxyapatite-coated stem in patients with Type C bone.