Polished, Collarless, Tapered, Cemented Stems for Primary Hip Arthroplasty May Exhibit High Rate of Periprosthetic Fracture at Short-Term Follow-Up.

BACKGROUND: Cemented stems are designed to follow 1 of 2 principles of fixation: composite beams or slide taper. Stems in the latter category have a collarless, polished, tapered (CPT) design and subside into the cement mantle, creating hoop stresses. We compared the rate of periprosthetic fracture (PPF) of stem designed with these 2 principles of fixation. In addition, we examined radiographic factors that may predispose to the development of PPF. METHODS: We retrospectively reviewed all patients who underwent primary THA by a single surgeon using highly polished cemented stems. PPF rates were compared between CPT stems (follow-up, 21 months; standard deviation [SD], 22) and composite beam stems (follow-up, 21.7 months; SD, 26). Demographic data were compared between patients with and without a PPF. Three preoperative radiographic parameters (canal bone ratio [CBR], canal-calcar ratio, and canal flare index), stem alignment, and cement mantle were compared in match-paired patients with and without a PPF (1:34). RESULTS: Seven of 1460 THA patients developed a PPF (0.479%); 4 hips of 185 with a CPT stem (2.2%); and 3 of 1275 hips with a composite beam stem (0.23%; P = .0064). Three of the 4 PPFs in the CPT group and none in the composite beam group were classified as Vancouver B2. The CBR in patients with a PPF was 0.50 (SD, 0.07) and 0.43 (SD, 0.07) in the match cohort of hips without PPF (P = .013). CONCLUSION: CPT stems may be associated with a higher risk of PPF that often require reoperation. An increased CBR may be a risk factor for postoperative PPF.

The Clinical Severity of Patients Diagnosed With an In-Hospital Pulmonary Embolism Following Modern, Elective Joint Arthroplasty Is Unrelated to the Location of Emboli in the Pulmonary Vasculature.

BACKGROUND: In the event of a postoperative pulmonary embolism (PE), it is generally believed that patients with centrally located emboli will have worse clinical symptoms than those with segmental or subsegmental ones. We studied if a relationship exists between the clinical severity at the time of PE diagnosis and the location of the emboli within the pulmonary vasculature. METHODS: All 269 patients who developed an in-hospital, computed tomography pulmonary angiography-proved, PE following elective total hip arthroplasty or total knee arthroplasty in our institution were studied. The clinical severity of the PE was calculated using the Pulmonary Embolism Severity Index (PESI) that classifies patients in 5 classes (class 5: most severe). All computed tomography pulmonary angiographies were re-reviewed to determine the location of the emboli within the pulmonary vasculature (central, segmental, or subsegmental-unilateral or bilateral). The association between PESI and the PE location was examined. RESULTS: The most proximal location of the emboli was central in 62, segmental in 139, and subsegmental in 68. There were 180 unilateral and 89 bilateral PE patients. There was no association between the PESI and the location of the emboli within the pulmonary vasculature (P = .32). Patients with bilateral or unilateral lung involvement had similar PESI (P = .78). CONCLUSION: The PESI, a recognized, validated predictor of mortality after PE was similar in patients with central, segmental, or subsegmental PE; and in patients with unilateral or bilateral lung involvement. The present study may aid clinicians while assessing and discussing the severity of PE symptoms with patients at the time of diagnosis.

One-Year All-Cause Mortality of Patients Diagnosed as Having In-Hospital Pulmonary Embolism After Modern Elective Joint Arthroplasty Is Low And Unaffected By Radiologic Severity.

BACKGROUND: We studied the 1-year complication rate of patients diagnosed as having a pulmonary embolism (PE) after elective total hip arthroplasty (THA) and total knee arthroplasty (TKA) surgery and the distribution of emboli in the pulmonary circulation, and determined if a relationship exists between the location of the PE and age, gender, body mass index, preoperative predisposing factors, American Society of Anesthesiology classification, type of surgery, prophylaxis, hospital stay, transfer to a higher level of care, and mortality. METHODS: Two hundred sixty-nine patients who developed an in-hospital PE proved by computed tomography pulmonary angiography after elective THA or TKA between 2005 and 2012 were studied. RESULTS: The most proximal location of the emboli was central in 62, segmental in 139, and subsegmental in 68. Nineteen patients (7%) developed a bleeding complication during PE treatment. Twenty-nine patients (11%) were readmitted during the first year. Two patients (0.74%) died: one had a segmental PE after TKA. He died 11 months after surgery due to an autopsy-proven sepsis. The second patient developed a segmental PE after THA. She was anticoagulated, developed an intracranial bleed, and died 8 months after surgery. Multivariate analysis showed that demographic variables, American Society of Anesthesiology class, preoperative comorbidities (with the exception of arrhythmia), and the presence of preoperative predisposing factors had no effect in the location of the PE. CONCLUSION: The 1-year mortality rate of these patients is low. Death can be caused by bleeding complications secondary to anticoagulation or by unrelated conditions. This information may aid clinicians while counseling patients who developed a PE after surgery, particularly those with small subsegmental emboli.

Risk Factors of Heterotopic Ossification Following Total Hip Arthroplasty in Patients With Ankylosing Spondylitis.

This study was to identify the risk factors of heterotopic ossification (HO) after total hip arthroplasty (THA) in ankylosing spondylitis. We analyzed 47 hips (24 patients) with ankylosing spondylitis that underwent primary THA. The incidence of HO was 14.9%. The risk factors were divided into modifiable and nonmodifiable factors. Female gender (P=0.008), preoperative ankylosed hip (P<0.001), occurrence of HO in previous surgery (P=0.036) were nonmodifiable risk factors which increased the prevalence of HO. Of the various modifiable risk factors, elevated preoperative ESR (P=0.007), elevated preoperative CRP (P=0.004) and prolonged duration of surgery (P=0.014) were associated with increased occurrence of HO. Perioperative medical intervention to reduce inflammation (ESR and CRP) may help to decrease HO.

Safety and efficacy of multimodal thromboprophylaxis following total knee arthroplasty: a comparative study of preferential aspirin vs. routine coumadin chemoprophylaxis.

Multimodal thromboprophylaxis encompasses preoperative VTE risk stratification, regional anesthesia, mechanical prophylaxis, and early mobilization. We determined if aspirin can be safely used for adjuvant chemoprophylaxis in patients who have a low thromboembolic risk. 1016 consecutive patients undergoing TKA received multimodal thromboprophylaxis. Aspirin was used in 67% of patients and Coumadin 33% (high risk patients, or who were on Coumadin before surgery). This study group was compared to 1001 consecutive patients who received multimodal thromboprophylaxis and routine Coumadin chemoprophylaxis. There was no significant difference in rates of VTE, PE, bleeding, complications, readmission and 90-day mortality between the two groups. There was a significantly higher rate of wound related complications in the control group (p=0.03). Multimodal thromboprophylaxis with aspirin given to the majority of patients at a low VTE risk is safe and effective in patients undergoing primary TKA.

Multimodal Thromboprophylaxis in Patients With a History of Venous Thromboembolism Undergoing Primary and Revision Knee Arthroplasty.

Background: Patients with a history of venous thromboembolism (VTE) undergoing total knee arthroplasty (TKA) are at a high risk of postoperative VTE. Purpose: In this high-risk population, we sought to evaluate the safety and efficacy of multimodal thromboprophylaxis. The regimen consisted of discontinuation of procoagulant medications, VTE risk stratification, regional anesthesia, rapid mobilization, perioperative use of pneumatic compression devices, vigorous ankle dorsiflexion during the recovery period, and chemoprophylaxis tailored to the patient's risk of VTE. Methods: We conducted a retrospective chart review of 141 consecutive patients with a history of VTE who underwent 177 elective TKA procedures between 2005 and 2019 by 2 arthroplasty surgeons at a single institution. The patients had a history of deep venous thrombosis (DVT) (n = 127; 72%), pulmonary embolism (PE) (n = 20; 11%), or both (n = 30; 17%). Postoperative chemoprophylaxis included aspirin (n = 20; 11%), anticoagulation (n = 135; 77%), or a combination of aspirin and anticoagulation (n = 21; 12%). Complications within 120 days, including VTE events, wound complications, bleeding, and unplanned readmissions, were recorded, as was 1-year mortality. Results: Five patients (2.8%) developed symptomatic DVT (3 distal, 2 proximal), and 4 patients (2.3%) developed symptomatic PE. The most common postdischarge complications were wound infection (n = 6; 3.4%) and stiffness requiring manipulation under anesthesia (n = 5; 2.8%). There was 1 emergency room visit and 13 unplanned readmissions; 3 patients developed intra-articular hematomas or prolonged wound drainage and recovered uneventfully. All patients were alive 1 year after surgery. Conclusion: The findings of this retrospective study suggest that multimodal prophylaxis may be safe and effective in patients with a history of VTE undergoing primary and revision TKA. More rigorous study is warranted.

Total Joint Arthroplasty in Patients With Atrial Septal Defects: What Are the 90-Day Complications?

Background: Congenital heart defects, such as atrial septal defects (ASDs) and patent foramen ovale (PFO), may increase the risk of embolic events in total hip or knee arthroplasty (THA/TKA). The objective of this study was to determine the 90-day incidence of intraoperative and postoperative embolic events and all other complications in patients with a known ASD/PFO who underwent primary hip and knee arthroplasty. Methods: This is a retrospective review of 160 patients with ASD/PFO undergoing 196 primary arthroplasties (94 THAs, 102 TKAs) at a single institution. The mean age was 64 years (standard deviation [SD] 11.1), 40.6% were male, and average body mass index was 31 kg/m2 (SD 7.2). The mean follow-up period was 19 months (SD 16). Forty-three percent of patients were on anticoagulation preoperatively. All patients received postoperative thromboprophylaxis (48% aspirin, 31% direct oral anticoagulants, 18% warfarin, 3% enoxaparin). Results: There were no embolic events identified. Fourteen patients (7%) developed complications within 90 days. Three had bleeding complications, and 8 had other nonoperative complications, which were all managed conservatively and had uneventful recoveries. Additionally, 3 patients had complications requiring reoperations: 2 for periprosthetic fractures (1 THA, 1 TKA) and 1 for a periprosthetic infection (TKA). Conclusions: In this cohort of patients with a known ASD/PFO undergoing THAs and TKAs, there were no cases of embolic events. However, it would be advisable to have a thorough cardiology evaluation to assess potential risks and benefits of defect repair prior to total joint arthroplasty and to reduce the risk of paradoxical embolic events and the necessity of potent anticoagulation. Level of evidence: Prognostic Level IV.

Risk factors for perioperative mortality after lower extremity arthroplasty: a population-based study of 6,901,324 patient discharges.

The goal of this study was to provide nationally representative data on characteristics of patients who died after hip and knee arthroplasty and to determine risk factors for such outcome. Using national in-patient data collected between 1990 and 2004, we identified a cumulative in-hospital mortality rate of 0.35% among an estimated 6,901,324 procedures. The strongest independent risk factors for in-hospital mortality were pulmonary embolism and cerebrovascular complications, which increased the odds for a fatal outcome by approximately 40-fold. Preoperative risk factors for in-hospital mortality were revision total hip arthroplasty, advanced age, and the presence of a number of comorbid diseases, predominantly dementia, renal, and cerebrovascular disease. Our results can be used to identify patients at risk for fatal outcome and implement interventions to reduce such risk.

Multimodal prophylaxis for venous thromboembolic disease after total hip and knee arthroplasty: current perspectives.

Life-threatening in the short term and leading to a high level of morbidity in the long term, venous thromboembolism (VTE) is the most fearful complication following lower limb arthroplasty. With advances in surgical procedure, anesthetic management and postoperative convalescence have altered the risks of venous thromboembolism after total joint arthroplasty in the lower extremity. The pathogenesis of VTE is multifactorial and includes the well-known Virchow's triad of hypercoagulability, venous stasis and endothelial damage. Therefore, it is appropriate to use a multimodal approach to thromboprophylaxis. Despite extensive research, the ideal multimodal prophylaxis against venous thrombolism has not been identified. So this article reviews the recent developments in multimodal prophylaxis for thromboembolism after total joint arthroplasty.

Multimodal prophylaxis in patients with a history of venous thromboembolism undergoing primary elective hip arthroplasty.

AIMS: We studied the safety and efficacy of multimodal thromboprophylaxis in patients with a history of venous thromboembolism (VTE) who undergo total hip arthroplasty (THA) within the first 120 postoperative days, and the mortality during the first year. Multimodal prophylaxis includes discontinuation of procoagulant medications, VTE risk stratification, regional anaesthesia, an intravenous bolus of unfractionated heparin prior to femoral preparation, rapid mobilization, the use of pneumatic compression devices, and chemoprophylaxis tailored to the patient's risk of VTE. METHODS: Between 2004 to 2018, 257 patients with a proven history of VTE underwent 277 primary elective THA procedures by two surgeons at a single institution. The patients had a history of deep vein thrombosis (DVT) (186, 67%), pulmonary embolism (PE) (43, 15.5%), or both (48, 17.5%). Chemoprophylaxis included aspirin (38 patients), anticoagulation (215 patients), or a combination of aspirin and anticoagulation (24 patients). A total of 50 patients (18%) had a vena cava filter in situ at the time of surgery. Patients were followed for 120 days to record complications, and for one year to record mortality. RESULTS: Postoperative VTE was diagnosed in seven patients (2.5%): DVT in five, and PE with and without DVT in one patient each. After hospitalization, three patients required readmiss-ion for evacuation of a haematoma, one for wound drainage, and one for monitoring of an elevated international normalized ratio (INR). Seven patients died (2.5%). One patient died five months postoperatively of a PE during open thrombectomy. She had discontinued anticoagulation. One patient died of a haemorrhagic stroke while receiving Coumadin. PE or bleeding was not suspected in the remaining five fatalities. CONCLUSION: Multimodal prophylaxis is safe and effective in patients with a history of VTE. Postoperative anticoagulation should be prudent as very few patients developed VTE (2.5%) or died of suspected or confirmed PE. Mortality during the first year was mostly unrelated to either VTE or bleeding. Cite this article: Bone Joint J 2020;102-B(7 Supple B):71-77.

Wear is reduced in THA performed with highly cross-linked polyethylene.

UNLABELLED: Highly cross-linked polyethylene (HCLPE) has been used extensively to decrease osteolysis and related implant failure in THA. We compared the wear rate of HCLPE and noncross-linked conventional PE (CPE) liners and the rate of radiographic calcar resorption and osteolysis in young patients (35-60 years of age) who underwent THA by one surgeon. Thirty-four patients (41 THAs) who received a hybrid THA using a HCLPE liner were match-paired for age, gender, body mass index, and diagnosis with a group of patients who underwent THA with identical implants but with a CPE liner. The minimum followup was 4 years (average, 5.3; range, 4-8 years). Using the Livermore measurement technique, the averages of total wear of the HCLPE and CPE liners were 0.01 mm (range, -0.23-0.4) and 0.64 mm (range, 0-1.7), respectively. The average annual wear was less for the HCLPE than the noncross-linked PE (0.002 mm, range, -0.05-0.1 versus 0.12 mm, range, 0-0.29, respectively). Four hips in the HCLPE group and 23 in the CPE group had calcar resorption measuring averages of 2.5 mm (range, 2-3) and 7.5 mm (range, 1.8-23.8), respectively. Periprosthetic osteolysis occurred in two and eight hips in the HCLPE and CPE groups, respectively. Longer followup is needed to determine if these findings will result in improved implant survivorship. LEVEL OF EVIDENCE: Level III, therapeutic study.

VKORC1 variant genotypes influence warfarin response in patients undergoing total joint arthroplasty: a pilot study.

UNLABELLED: Warfarin dosing algorithms do not account for genetic mutations that can affect anticoagulation response. We retrospectively assessed to what extent the VKORC1 variant genotype would alter the likelihood of being a hyperresponder or hyporesponder to warfarin in patients undergoing total joint arthroplasty. We used the international normalized ratio (INR) on the third postoperative day of 3.0 or greater to define warfarin hyperresponders and 1.07 or less to define hyporesponders. A control group of normal responders was identified. From a cohort of 1125 patients receiving warfarin thromboprophylaxis, we identified 30 free of predisposing factors that could affect warfarin response: 10 hyperresponders, eight hyporesponders, and 12 normal responders. Homozygous carriers of the VKORC1 mutant AA genotype were more likely (compared with carriers of GA or GG genotypes) to be hyperresponders (odds ratio, 7.5; 95% confidence interval, 1.04-54.1). Homozygous carriers of the GG (normal) genotype were more likely (compared with carriers of AA or GA genotypes) to be hyporesponders (odds ratio, 9; 95% confidence interval, 1.14-71). Preoperative screening for the VKORC-1 genotype could identify patients with a greater potential for being a hyperresponder or hyporesponder to warfarin. This may allow an adjusted pharmacogenetic-based warfarin dose to optimize anticoagulation, reducing postoperative risks of bleeding and thrombosis or embolism. LEVEL OF EVIDENCE: Level III, diagnostic study.

Aspirin decreases the prevalence and severity of heterotopic ossification after 1-stage bilateral total hip arthroplasty for osteoarthrosis.

Heterotopic ossification (HO) is a frequent complication after total hip arthroplasty (THA). We retrospectively evaluated the prevalence and severity of HO in patients with osteoarthrosis who underwent 1-stage bilateral THA (OSBTHA) and compared those who received aspirin with those who received Coumadin for postoperative chemothromboprophylaxis. The aspirin group consisted of 66 patients (132 hips), with a mean age of 64 years (SD, 8.5). The Coumadin group consisted of 67 patients (134 hips), with a mean age of 60 years (SD, 10.2). Overall, HO was detected in 124 hips (46.6%). There were 43 hips (32.5%) with HO in the aspirin group and 81 (60.4%) in the Coumadin group (P < .00005). Aspirin significantly decreases the prevalence and severity of HO in comparison to Coumadin after OSBTHA.

Surface finish mechanics explain different clinical survivorship of cemented femoral stems for total hip arthroplasty.

The ability of bone cement to adhere to the implant surface is dependent on the surface finish. Stems with a rough surface finish require greater force to disrupt their interface with the cement than do stems with a smooth or polished surface. However, if micromotion occurs at the cement-metal interface, the fretting of a smoother surface implant results in less cement and metallic abrasion than an implant with a rough surface finish. Today, surgeons implant femoral stems with a wide variety of surface finish and textures that are supported by the previously mentioned contrasting philosophy of fixation. This article presents the micro and macro surface finish mechanics, history, and rationale for changes in surface finish, the clinical and operative implications of changes in surface finish, the retrieval analysis, and the clinical evidence that examine the consequences of changes in surface finish in the outcome of cemented femoral stems for total hip arthroplasty. Current data and our own experience support the use of cemented femoral stems with a smooth or polished surface finish.

Measuring improvement following total hip and knee arthroplasty using patient-based measures of outcome.

BACKGROUND: Patient-derived outcome scales have become increasingly important to physicians and clinical researchers for measuring improvement in function after surgery. The goal of the present study was to evaluate the ability of health-status instruments to measure early functional recovery after total hip and total knee arthroplasty. METHODS: Four hundred and six patients undergoing total hip arthroplasty and 266 patients undergoing total knee arthroplasty completed health-status questionnaires preoperatively and six months postoperatively to determine the standardized response mean. In the second phase of the study, a group of patients undergoing knee and hip arthroplasty were evaluated with several instruments before and after surgery to test for postoperative ceiling effects. RESULTS: The standardized response mean at six months was 1.7 for the MODEMS Hip Core, 1.2 for the MODEMS Knee Core, and 1.5 and 1.1 for the Physical Component Summary of the SF-36 for patients managed with hip and knee replacement, respectively. A standardized response mean of 1.0 is generally satisfactory for measuring improvement in orthopaedic surgery. In Phase 2 of the study, the vast majority of patients who had a score of 95 to 100 (that is, a maximum or near-maximum score) on the joint-specific scales generally believed that the hip or knee was normal and could not be better. CONCLUSIONS: The MODEMS, Oxford, and WOMAC scales all demonstrated a ceiling effect following total knee and total hip arthroplasty. These scores likely reflected the patients' perception of the status of the knee or hip rather than an inability to measure their improvement beyond the highest possible score. The Physical Component Summary score of the SF-36 had similar standardized response means when compared with hip and knee-specific instruments, and, therefore, consideration should be given to using this scale without a joint-specific scale for the measurement of improvement following total knee and total hip replacement, as a way to decrease responder burden (that is, the time required to complete the questionnaires).

The early recovery of cognitive function after total-hip replacement under hypotensive epidural anesthesia.

BACKGROUND AND OBJECTIVES: Recovery of cognitive function immediately after major surgery has not been previously reported, partly because of residual drug effects and pain. METHODS: Changes in cognitive function were assessed using the Stroop Color and Word Test (SCWT), which was performed preoperatively, and 1 and 2 hours after total-hip replacement performed under hypotensive epidural anesthesia. In this case series, patients were sedated with propofol alone and had a lumbar plexus block performed at the end of surgery. RESULTS: The SCWT was completed in 52 of 55 patients at either 1 or 2 hours after surgery. A significant reduction in cognitive function was noted 1 hour after surgery but a return toward baseline occured 2 hours after surgery. Age older than 70 years adversely affected recovery of cognitive function, but neither the preoperative diagnosis of hypertension nor the degree or duration of intraoperative hypotension (mean arterial pressure less than 45 mmHg) influenced cognitive function. CONCLUSION: The Stroop Color and Word Test can be used to assess change in cognitive function immediately after surgery. Total-hip replacement performed under regional anesthesia with propofol sedation enables recovery of cognitive function (as assessed by SCWT) 2 hours after surgery.

Preoperative planning for primary total hip arthroplasty.

Preoperative planning is of paramount importance in obtaining reproducible results in modern hip arthroplasty. Planning helps the surgeon visualize the operation after careful review of the clinical and radiographic findings. A standardized radiograph with a known magnification should be used for templating. The cup template should be placed relative to the ilioischial line, the teardrop, and the superolateral acetabular margin, so that the removal of the supportive subchondral bone is minimal and the center of rotation of the hip is restored. When acetabular abnormalities are encountered, additional measures are necessary to optimize cup coverage and minimize the risk of malposition. Templating the femoral side for cemented and cementless implants should aim to optimize limb length and femoral offset, thereby improving the biomechanics of the hip joint. Meticulous preoperative planning allows the surgeon to perform the procedure expediently and precisely, anticipate potential intraoperative complications, and achieve reproducible results.

Long-term results of total hip arthroplasty with a cemented custom-designed swan-neck femoral component for congenital dislocation or severe dysplasia: a follow-up note.

BACKGROUND: This follow-up study updates the results in a consecutive series of nineteen cemented total hip replacements with a swan-neck femoral component in patients with congenital dislocation or severe hip dysplasia. The series was previously reported on in 1993. METHODS: The patients were petite, with an average height of 152 cm and an average weight of 50 kg, and the femoral canals could not accommodate an off-the-shelf femoral component. Sixteen of the nineteen hips were available for follow-up at an average of 13.3 years (range, eleven to twenty years). Fourteen hips had up-to-date clinical and radiographic examinations. RESULTS: At the time of the latest follow-up, thirteen hips were rated as excellent; two, as good; and one, as a failure because of loosening of both components requiring revision eleven years after the index operation. Another hip required acetabular revision because of loosening fifteen years after the index operation. The rates of femoral and acetabular component revision were 6% and 12.5%, respectively. Radiographic analysis demonstrated that no femoral component was loose. One cup was definitely loose at 19.5 years, and three cups were possibly loose at an average of fourteen years. The radiographic rate of acetabular loosening was 33%. The total rate of cup failure (radiographic loosening and revision) was 43%. CONCLUSIONS: The excellent clinical and radiographic results associated with the swan-neck femoral component, and the 94% rate of survival, at an average of 13.3 years (range, eleven to twenty years) indicate that the biomechanical objectives of this custom-designed prosthesis for patients with congenital dislocation or severe hip dysplasia were met. On the basis of this favorable long-term experience, we still use this prosthesis when the anatomic abnormality cannot be adequately addressed by use of a commercially available prosthetic component.

Clinical and radiographic results associated with a modern, cementless modular cup design in total hip arthroplasty.

BACKGROUND: First-generation cementless modular cups reproducibly achieved fixation to bone but were associated with unacceptable rates of pelvic osteolysis and mechanical failure. Consequently, second-generation cups were developed with shells that had a limited number of holes (or no holes) as well as improved locking mechanisms, a polished inner surface, and increased conformity with the liner. The purpose of the present study was to evaluate the clinical and radiographic results associated with the use of a second-generation acetabular component for primary total hip arthroplasty. METHODS: Two hundred and ninety-seven patients underwent 335 consecutive primary total hip arthroplasties that were performed by a single surgeon with a second-generation modular acetabular component. All cups were implanted with a press-fit technique. Ten patients were lost to follow-up, and sixteen died from unrelated causes. The remaining 271 patients (308 hips) were followed clinically (with the Hospital for Special Surgery hip-scoring system) and radiographically for four to seven years. RESULTS: One cup was revised because of aseptic loosening. There were seven additional revisions: five were performed because of aseptic loosening of the stem with a well-fixed cup, and two were performed because of deep infection. Among the 271 patients who were alive at the time of the last follow-up, 266 (98%) had retention of the cup and 264 (97%) had retention of both components with a good or excellent clinical result. In the group of 229 patients (262 hips) with complete radiographic follow-up, 259 cups were well fixed and the average wear rate (for the 246 hips for which this rate could be calculated) was 0.09 mm/yr. Osteolysis was detected in twelve hips (5%) and was associated with male gender (p = 0.001) and the annual wear rate (p = 0.004). The extent of calcar resorption was also associated with the annual wear rate (p < 0.001). CONCLUSIONS: This second-generation acetabular cup design predictably achieved bone fixation and was associated with low rates of revision for loosening and osteolysis after intermediate-term follow-up.

Correlation of thrombophilia and hypofibrinolysis with pulmonary embolism following total hip arthroplasty: an analysis of genetic factors.

BACKGROUND: The increased thromboembolic risk associated with total hip arthroplasty is multifactorial. We assessed whether the prevalence of abnormalities shown by newer genetic screening tests for thrombophilia and hypofibrinolysis was higher in patients in whom pulmonary embolism had developed after total hip arthroplasty than it was in matched control patients. METHODS: Fourteen patients with documented pulmonary embolism after total hip arthroplasty and fourteen matched control patients who had undergone total hip arthroplasty without any clinical indication of thromboembolism were evaluated for risks of thrombophilia and hypofibrinolysis. Functional tests of hemostasis included evaluations of prothrombin time; activated partial thromboplastin time; levels of fibrinogen, serum homocysteine, protein C and S, and antithrombin III; activated protein-C resistance; and dilute Russell viper venom time. Molecular genetic testing was performed for factor-V Leiden, prothrombin promoter G20210A, methylenetetrahydrofolate reductase C677T, plasminogen activator inhibitor-1 4G/4G, and platelet glycoprotein IIb/IIIa A1/A2 or A2/A2 mutations. RESULTS: The total number of genetic thrombophilic abnormalities identified was higher in the pulmonary embolism group (twenty-four abnormalities) than in the control group (fifteen abnormalities). Only patients with pulmonary embolism were found to have heterozygosity or homozygosity for the prothrombin G20210A mutation (four of fourteen patients; p = 0.05 compared with the control group) and a decreased antithrombin-III level (three of thirteen patients; p = 0.10 compared with the control group). Patients with pulmonary embolism were much more likely than control patients to have at least one thrombophilic abnormality: seven of fourteen patients with pulmonary embolism had a low antithrombin-III level or the prothrombin G20210A gene mutation compared with none of the fourteen in the control group (Fisher exact test, p < 0.01). The presence of the prothrombin G20210A gene mutation was significantly correlated with pulmonary embolism (r = 0.41, p = 0.03), as was the presence of least one abnormality (a low antithrombin-III level or the presence of the prothrombin G20210A gene mutation) (r = 0.58, p = 0.001). CONCLUSIONS: Genetic thrombophilia and hypofibrinolysis were more frequent in patients who had had pulmonary embolism after total hip arthroplasty than in those who had not. The presence of multiple genetic thrombophilic polymorphisms, particularly prothrombin G20210A and antithrombin III, rather than any single genetic prothrombotic abnormality, appears to signal an increased thromboembolic risk in patients undergoing total hip arthroplasty. Future refinements and availability of these tests will likely allow preoperative identification of patients with an increased genetic predisposition for thromboembolism.