Acetabular cup migration after primary cementless total hip arthroplasty in rheumatoid arthritis and its influencing factors: a comparative study with osteoarthritic hip.

PURPOSE: To compare the radiographic migration profiles of primary cementless total hip arthroplasty (THA) between patients with rheumatoid arthritis (RA) and those with osteoarthritis (OA). METHODS: A total of 197 patients (215 hips) who underwent cementless THA for RA or OA between January 2001 and January 2013 and followed up for a minimum of 5.5 years were included. Ninety-four RA patients (109 hips) were compared with 103 OA patients (106 hips). Radiological evaluation was performed for acetabular cup loosening, and cup migration was measured using Einzel-Bild-Röntgen-Analyse (EBRA) software. Multiple variables were assessed to identify influencing factors for cup migration. RESULTS: Early cup migration was observed in 13 hips (11.9%) in the RA group and four hips (3.8%) in the OA group, showing a significant difference (p = 0.041). Acetabular cup loosening occurred in three cups (2.8%) in the RA group and in one cup (0.9%) in the OA group, showing no significant difference (p = 0.321). Total cup migration was higher in the RA group (2.62 mm) than in the OA group (1.44 mm, p = 0.005). Total cup migration was significantly higher in patients aged < 50 years than in those aged > 50 years (p = 0.005). Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibody influenced total cup migration. Patients with seropositive RA showed significantly higher total cup migration and early cup migration incidence than those with seronegative RA (p = 0.005, p = 0.038, respectively). CONCLUSIONS: Acetabular cups in primary cementless THAs of RA patients were less stable in terms of cup migration compared with that of OA patients.

Automatic Disease Annotation From Radiology Reports Using Artificial Intelligence Implemented by a Recurrent Neural Network.

OBJECTIVE: Radiology reports are rich resources for biomedical researchers. Before utilization of radiology reports, experts must manually review these reports to identify the categories. In fact, automatically categorizing electronic medical record (EMR) text with key annotation is difficult because it has a free-text format. To address these problems, we developed an automated system for disease annotation. MATERIALS AND METHODS: Reports of musculoskeletal radiography examinations performed from January 1, 2016, through December 31, 2016, were exported from the database of Hanyang University Medical Center. After sentences not written in English and sentences containing typos were excluded, 3032 sentences were included. We built a system that uses a recurrent neural network (RNN) to automatically identify fracture and nonfracture cases as a preliminary study. We trained and tested the system using orthopedic surgeon-classified reports. We evaluated the system for the number of layers in the following two ways: the word error rate of the output sentences and performance as a binary classifier using standard evaluation metrics including accuracy, precision, recall, and F1 score. RESULTS: The word error rate using Levenshtein distance showed the best performance in the three-layer model at 1.03%. The three-layer model also showed the highest overall performance with the highest precision (0.967), recall (0.967), accuracy (0.982), and F1 score (0.967). CONCLUSION: Our results indicate that the RNN-based system has the ability to classify important findings in radiology reports with a high F1 score. We expect that our system can be used in cohort construction such as for retrospective studies because it is efficient for analyzing a large amount of data.

Acetabular revision arthroplasty using press-fitted jumbo cups: an average 10-year follow-up study.

INTRODUCTION: Acetabular revision arthroplasty using jumbo cups for moderate-to-severe acetabular defects has varied outcomes. We evaluated the clinical and radiological outcomes of acetabular revision arthroplasty using a press-fitted jumbo cup and sought to identify factors that influence outcomes during intermediate follow-up. MATERIALS AND METHODS: Eighty patients (47 men, 33 women; 80 hips) who underwent acetabular revision arthroplasty using press-fitted jumbo cups were included. The mean follow-up period was 10.4 years. Harris hip score (HHS), presence of groin pain, radiographic results, and Kaplan-Meier survival curves were evaluated. Implant design and surgery-related and patient-related factors were assessed to identify influential factors for cup loosening. Migration and wear analyses were performed using Einzel-Bild-Röntgen-Analyse software. RESULTS: The mean preoperative HHS of 53 had improved to 77 at the final follow-up (p = 0.005). Nine patients experienced groin pain. Acetabular cup loosening was observed in seven cups (8.7%), and one jumbo cup was replaced with a reinforcement cage. The survival rate of the acetabular cup was 91% at 16 years according to the Kaplan-Meier analysis. Osteolysis was identified around the cup in six cases (7.5%). Acetabular cup loosening occurred more frequently in patients with conventional polyethylene liners than in those with highly cross-linked polyethylene liners (p = 0.045). The mean total migration was 1.52 mm, and the mean total wear was 0.98 mm. There was a positive correlation between total migration and total wear (p = 0.023; Spearman's rho = 0.388). The mean wear rate of the patients with the cup inclination angle < 50° was significantly lower than those with the cup inclination angle > 50° (p = 0.001). There were four cases of complications (three dislocations and one infection) that did not require revision surgery. CONCLUSION: Press-fitted jumbo cups for acetabular revision arthroplasty exhibited encouraging results during follow-up for an average of 10 years. Use of highly cross-linked polyethylene liners and proper placement of the acetabular component with an inclination angle < 50° may contribute to better clinical outcomes after acetabular revision arthroplasty with jumbo cups.

Long-Term Outcomes After Metal-on-Metal Total Hip Arthroplasty With a 28-mm Head: A 17- to 23-Year Follow-Up Study of a Previous Report.

BACKGROUND: Second-generation, metal-on-metal total hip arthroplasty (MoM THA) using a 28-mm head has shown favorable results compared with large head MoM THA. The purpose of this study is to evaluate the long-term outcomes of cementless primary MoM THA with a 28-mm head and the incidence of osteolysis using computed tomography. METHODS: A total of 92 patients (53 men and 39 women) who underwent primary cementless MoM THA (114 hips) with a 28-mm head were enrolled in this study. Their mean age was 46.2 years at the time of surgery. The mean follow-up duration was 20 years. The Harris hip score, presence of thigh or groin pain, radiographic results, presence of peri-implant osteolysis, histologic analysis, and Kaplan-Meier survival curves were evaluated. RESULTS: The mean preoperative Harris hip score of 50.5 improved to 85.1 at the final follow-up. Eight patients (8 hips) experienced groin pain, but none had thigh pain. Twelve revisions (6.2%) were performed including 10 hips for aseptic loosening with osteolysis and 2 hips for periprosthetic fracture around the stem. At 23 years, 91% of patients were free from revision of the acetabular component due to aseptic loosening and 90.1% were free from revision of both femoral and acetabular components due to any reason. Osteolysis was identified around the cup in 12 cases (10.5%) and around the stem in 7 cases (6.1%). CONCLUSION: MoM THA with a 28-mm head showed a relatively low rate of aseptic implant loosening at a mean follow-up of 20 years.

Dislocations after use of dual-mobility cups in cementless primary total hip arthroplasty: prospective multicentre series.

BACKGROUND: The purpose of this study was to investigate the incidence of dislocation and specific complications of the dual-mobility cup. METHODS: The arthroplasties involved 167 hips in 165 patients; 51 hips (30.5%) were in men and 116 (69.4%) were in women. The active articulation E1® dual-mobility cup (Biomet, Warsaw, IN, USA) was used, and the surgical approach was posterolateral in 120 hips and anterolateral in 47 hips. RESULTS: Four (2.3%) dislocations were observed. Mean time of dislocation was 30.5 days post-operatively. Three incomplete reductions occurred during closed reduction. When comparing parameters between dislocation and no-dislocation groups, there were no differences in patient and surgical parameters. However, all dislocations occurred in patients with femoral neck fractures and in the posterolateral approach group. CONCLUSION: The incidence of dislocation in total hip arthroplasty (THA) using a dual-mobility cup was acceptable, and cup diameter of the dislocation group was substantially larger than that of no-dislocation group. Based on clinical outcomes of our study, we conclude that the dual-mobility cup is a reliable option in THA, and further studies are necessary.

The incidence of hip dislocation and suture failure according to two different types of posterior soft tissue repair techniques in total hip arthroplasty: a prospective randomized controlled trial.

PURPOSE: Although the posterolateral approach for hip arthroplasty is popular and has numerous advantages, it has been known to have a propensity for dislocation. The repair of short external rotator muscles with capsule is important for reducing dislocation. The purpose of this study is to investigate the incidence of suture failure, dislocation, and time to failure for two repair techniques for posterior soft tissue repair during total hip arthroplasty. METHODS: In this study of 167 total hip arthroplasties in 159 patients, we reattached the short external rotator tendon with posterior capsule to the greater trochanter transosseously (tendon-to-bone, 87 hips) or the gluteus medius tendon (tendon-to-tendon, 80 hips). Radiopaque markers were attached to each suture side < 1.2 cm apart. The distance between the markers was radiographically measured at variable time points postoperatively. Failure was defined by a distance between markers of ≥ 2.5 cm or marker invisibility. The mean follow-up period was 28.8 (12-45) months. RESULTS: Suture failure was observed less frequently in the tendon-to-bone group (18.4%) than in the tendon-to-tendon group (65%; p < 0.001). Failure mostly occurred within two weeks post-operatively: 93.8% for tendon-to-bone repair (p < 0.001) and 90.4% for tendon-to-tendon repair (p = 0.025). The dislocation rate was significantly higher in the tendon-to-tendon group (7. vs 1.1%; p = 0.041). A significant correlation was observed between suture failure and dislocation (p = 0.013). CONCLUSIONS: Tendon-to-bone repair is superior to tendon-to-tendon repair based on lower suture failure and dislocation rates.

Measurement of change on medial and lateral joint gaps by navigation system in multi-radius PS TKA.

BACKGROUND: The purpose of this study was to evaluate the joint gap kinematics in posterior-stabilized total knee arthroplasty (PS TKA). METHODS: Between January 2010 and April 2011, 44 consecutive patients (55 knees) who underwent primary PS TKA using the navigation system were assessed. There were 37 women and 7 men with a mean age at operation of 63 years (range; 58-73 years). After fixation of all components with cement and insertion of polyethylene trial insert, medial and lateral joint gap measurements were carried out without distraction force and separately using a navigation system on each flexion angles. The joint gaps were measured before and after deflation of tourniquet, first with patella everted and then reduced. RESULTS: Deflation of tourniquet did not effect on gap. In patellofemoral joint reduction situation, the medial gap relatively maintained throughout the range of knee motion, but the lateral gap is gradually decreasing with knee flexion from 30° to 120° flexion. However, in patellar eversion situation, the medial gap showed a significant increase and also statistically significantly increased compared with patellar reduced position over 90° knee flexion status, but the lateral gaps are decreased compared with patellofemoral reduction situation throughout the range of knee motion except full flexion status. In more physiologic status that is patella reduced and tourniquet deflated status, the average medial joint gap change was 2.30 ± 1.64 mm and the average lateral joint gap change was 2.90 ± 1.53 mm throughout the range of motion. CONCLUSIONS: Medial and lateral joint gaps showed different patterns with patellar eversion and patellofemoral joint reduction. However, such changes occurred within 3 mm in average throughout whole range of knee motion even with multi-radius femoral component.

Assessment of osteoporosis using pelvic diagnostic computed tomography.

The purpose of the present study is to determine if a correlation exists between bone mineral density (BMD) obtained from dual energy X-ray absorptiometry (DXA) and Hounsfield unit (HU) from pelvic diagnostic computed tomography (dCT), and to evaluate whether HU could be used to identify osteoporosis. Seventy-nine patients were included in this study. HU values were measured in three different sections: the head-neck junction of the femur, the middle portion of the femoral neck, and the intertrochanter of the femur (IT). In each sectional image, HU values were measured at two regions of interest: cortical and cancellous bone (HU_t) and cancellous bone. The correlation between BMD and HU_t of IT was significant (r = 0.839, p < 0.01). In IT, the area under the curve value of HU_t was 0.875 (0.796-0.955). We found that a HU_t of IT <170 can be regarded as indicating osteoporosis: its positive predictive value is 96.9 %. A HU_t of IT >210 can be regarded as indicating an absence of osteoporosis: its negative predictive value is 84.6 %. In conclusion, we found that a significant correlation between HU of pelvic dCT and BMD of DXA, and HU potentially provided an alternative method for determining regional BMD. Therefore, pelvic dCT could possibly be a supplementary method for initial diagnosis of osteoporosis and for initiation of treatment.

Factors associated with atypical femoral fracture.

We aimed to investigate the proportion of atypical femoral fractures (AFF) among Korean femoral fracture patients and examined the factors associated with the development of AFF. Between 2003 and 2013, 607 female patients with low-energy femoral fractures who were hospitalized at a single university hospital were retrospectively enrolled in this study. Patients were classified into two groups according to the fracture site: Patients with subtrochanteric or diaphyseal femoral fractures were included in the AFF group, while patients with intertrochanteric or neck fractures were included in the typical femoral fracture (TFF) group. After comparing clinical and radiographic characteristics between groups, we used multivariable logistic regression analysis to explore risk factors for AFF. Thirty patients (4.9 %) with AFF and 577 patients (95.1 %) with TFF were identified. The AFF group was younger than the TFF group (p < 0.01), and more patients with AFF were treated with bisphosphonate (BP) (p < 0.01) or proton-pump inhibitor (p = 0.02). When comparing the radiographic parameters, the AFF group tended to have a higher cortical thickness index (p = 0.02) and lateral-to-medial cortex ratio (p < 0.01). After adjusting for clinical variables, BP use (OR 8.09, CI 3.09-21.19) and younger age (OR 1.06, CI 1.01-1.11) were associated with AFF. The proportion of AFF was 4.9 % among patients with femoral fractures. Younger age and use of BP before fracture increased the risk of development of AFF in Korean patients.

Isolated acetabular revision with ceramic-on-ceramic bearings using a ceramic head with a metal sleeve.

The purpose of this study is to evaluate results of isolated acetabular revision with ceramic-on-ceramic bearings using a ceramic head with a metal sleeve. A retrospective review of fifty-three hips was performed. The mean patient age was 49.9years and the mean follow-up period was 5.7years. The mean modified Harris hip score improved from 47.5, pre-operatively, to 84.7 at the time of last follow-up (P<0.001). Two patients reported squeaking of the hip. Three patients experienced loosening cup, necessitating re-revision surgery. There was a significant difference of acetabular bone defect between loose cup group and stable cup group (P=0.018). There were no ceramic fractures and no osteolysis. The survival rate of the acetabular cup at the mid-term follow-up was 94.3%. In conclusion, ceramic head with a metal sleeve can be a reliable option for isolated acetabular revision.

Angiotensin Receptor Blockers and the Risk of Suspected Drug-Induced Liver Injury: A Retrospective Cohort Study Using Electronic Health Record-Based Common Data Model in South Korea.

INTRODUCTION: Angiotensin receptor blockers are widely used antihypertensive drugs in South Korea. In 2021, the Korea Ministry of Food and Drug Safety acknowledged the need for national compensation for a drug-induced liver injury (DILI) after azilsartan use. However, little is known regarding the association between angiotensin receptor blockers and DILI. OBJECTIVE: We conducted a retrospective cohort study in incident users of angiotensin receptor blockers from a common data model database (1 January, 2017-31 December, 2021) to compare the risk of DILI among specific angiotensin receptor blockers against valsartan. METHODS: Patients were assigned to treatment groups at cohort entry based on prescribed angiotensin receptor blockers. Drug-induced liver injury was operationally defined using the International DILI Expert Working Group criteria. Cox regression analyses were conducted to derive hazard ratios and the inverse probability of treatment weighting method was applied. All analyses were performed using R. RESULTS: In total, 229,881 angiotensin receptor blocker users from 20 university hospitals were included. Crude DILI incidence ranged from 15.6 to 82.8 per 1000 person-years in treatment groups, most were cholestatic and of mild severity. Overall, the risk of DILI was significantly lower in olmesartan users than in valsartan users (hazard ratio: 0.73 [95% confidence interval 0.55-0.96]). In monotherapy patients, the risk was significantly higher in azilsartan users than in valsartan users (hazard ratio: 6.55 [95% confidence interval 5.28-8.12]). CONCLUSIONS: We found a significantly higher risk of suspected DILI in patients receiving azilsartan monotherapy compared with valsartan monotherapy. Our findings emphasize the utility of real-world evidence in advancing our understanding of adverse drug reactions in clinical practice.

Anterior operation for unstable thoracolumbar and lumbar burst fractures: tricortical autogenous iliac bone versus titanium mesh cage.

STUDY DESIGN: We retrospectively compared 25 cases that used the autogenous iliac bone grafting with 18 cases that used a titanium mesh cage for reconstruction of the vertebral body. OBJECTIVE: To analyze clinical and radiographic results of the autogenous iliac bone and a titanium mesh cage used to reconstruct the vertebral body. SUMMARY OF BACKGROUND DATA: Grafting of the autogenous iliac bone as a strut bone has been traditionally applied for reconstruction of the spine using anterior approach. Although grafting the autogenous iliac bone as a strut bone achieves a high bone fusion rate, it has reported complications in the donor site. For this reason, bone fusion with a mesh cage has been introduced. METHODS: Between March 2000 and December 2010, 43 cases that underwent decompression and instrumented fusion for unstable burst fractures using the anterior approach were enrolled. Levels of injury were T12 in 8 cases, L1 in 19 cases, L2 in 11 cases, and L3 in 5 cases. The mean follow-up period was 64.5 months (range, 14-129 mo). RESULTS: The local kyphotic angle in the group that used the tricortical autogenous iliac bone (group A) was measured 24.81±2.27 degrees preoperatively and 4.95±0.61 degrees at the last follow-up. The angle in the group that used a titanium mesh cage (group B) was 25.21±1.55 degrees preoperatively and 3.9±0.43 degrees at the last follow-up. Both groups obtained bone fusion of grade I and II by Bridwell fusion criteria. The operation site visual analog scale and Korean Oswestry disability index did not differ significantly between 2 groups. Donor site visual analog scale and the operation time was significantly in favor of group B (P<0.05). CONCLUSIONS: Titanium mesh cage filled with the autogenous cancellous bone shortened operation time and reduced the risk of complications in the donor site compared with the group that used the tricortical iliac bone.

Is second generation metal-on-metal primary total hip arthroplasty with a 28 mm head a worthy option?: a 12- to 18-year follow-up study.

To determine whether MoM THA with a small head is still worthy of use, we investigated survivorship, complications, and factors influencing failure. Of 149 consecutive patients (195 hips), 141 (180 hips) of mean age 43 (19-55) years were available for review at a mean of 14.4 years postoperatively. Survivorship for cup revision for any cause was 97.8% at 18.4 years postoperatively. Nine hips generated complaints of groin pain; six showed periacetabular osteolysis, one had pain without radiological change, and two were diagnosed as symptomatic pseudotumors. Four of six hips with periacetabular osteolysis or aseptic loosening were revised. Surgery- and patient-related factors had no effect in results. Our results are encouraging, however, further study will be necessary to determine the incidence and fates of pseudotumors after MoM THA with a small head.

Dislocation after Revision Total Hip Arthroplasty: A Comparison between Dual Mobility and Conventional Total Hip Arthroplasty.

Purpose: The objective of this study was to analyze the results from a cohort of patients who underwent a revision total hip arthroplasty (THA) using a dual mobility cup (DMC) implant. Materials and Methods: A retrospective review of revised THAs was conducted using the database from a single tertiary referral hospital. A total of 91 revision THAs from 91 patients were included in the study. There were 46 male hips and 45 female hips. The mean age was 56.3±14.6 years, and the mean follow-up period was 6.4±5.9 years. In performance of revision THAs, the DMC implants were used in 18 hips (19.8%), and the conventional implants were used in 73 hips (80.2%). Results: During the follow-up period, three dislocations were identified, and the overall dislocation rate was 3.3%. Early dislocation (at one month postoperatively) occurred in one patient, while late dislocation (at a mean of 7.5 years) occurred in two patients. There was no occurrence of dislocation in the DMC group (0%), and three dislocations were detected in the conventional group (4.1%). However, no significant difference in the rate of dislocation was observed between the two groups (P=0.891). Conclusion: Although the rate of dislocation was higher in the conventional group, there were no statistically significant differences between the two groups due to the small number of patients. Nevertheless, we believe that the dual mobility design is advantageous in terms of reducing dislocation rate and can be recommended as an option for a revision THA.

Feasibility Study of Federated Learning on the Distributed Research Network of OMOP Common Data Model.

OBJECTIVES: Since protecting patients' privacy is a major concern in clinical research, there has been a growing need for privacy-preserving data analysis platforms. For this purpose, a federated learning (FL) method based on the Observational Medical Outcomes Partnership (OMOP) common data model (CDM) was implemented, and its feasibility was demonstrated. METHODS: We implemented an FL platform on FeederNet, which is a distributed clinical data analysis platform based on the OMOP CDM in Korea. We trained it through an artificial neural network (ANN) using data from patients who received steroid prescriptions or injections, with the aim of predicting the occurrence of side effects depending on the prescribed dose. The ANN was trained using the FL platform with the OMOP CDMs of Kyung Hee University Medical Center (KHMC) and Ajou University Hospital (AUH). RESULTS: The area under the receiver operating characteristic curves (AUROCs) for predicting bone fracture, osteonecrosis, and osteoporosis using only data from each hospital were 0.8426, 0.6920, and 0.7727 for KHMC and 0.7891, 0.7049, and 0.7544 for AUH, respectively. In contrast, when using FL, the corresponding AUROCs were 0.8260, 0.7001, and 0.7928 for KHMC and 0.7912, 0.8076, and 0.7441 for AUH, respectively. In particular, FL led to a 14% improvement in performance for osteonecrosis at AUH. CONCLUSIONS: FL can be performed with the OMOP CDM, and FL often shows better performance than using only a single institution's data. Therefore, research using OMOP CDM has been expanded from statistical analysis to machine learning so that researchers can conduct more diverse research.

Ranitidine Use and Incident Cancer in a Multinational Cohort.

Importance: Ranitidine, the most widely used histamine-2 receptor antagonist (H2RA), was withdrawn because of N-nitrosodimethylamine impurity in 2020. Given the worldwide exposure to this drug, the potential risk of cancer development associated with the intake of known carcinogens is an important epidemiological concern. Objective: To examine the comparative risk of cancer associated with the use of ranitidine vs other H2RAs. Design, Setting, and Participants: This new-user active comparator international network cohort study was conducted using 3 health claims and 9 electronic health record databases from the US, the United Kingdom, Germany, Spain, France, South Korea, and Taiwan. Large-scale propensity score (PS) matching was used to minimize confounding of the observed covariates with negative control outcomes. Empirical calibration was performed to account for unobserved confounding. All databases were mapped to a common data model. Database-specific estimates were combined using random-effects meta-analysis. Participants included individuals aged at least 20 years with no history of cancer who used H2RAs for more than 30 days from January 1986 to December 2020, with a 1-year washout period. Data were analyzed from April to September 2021. Exposure: The main exposure was use of ranitidine vs other H2RAs (famotidine, lafutidine, nizatidine, and roxatidine). Main Outcomes and Measures: The primary outcome was incidence of any cancer, except nonmelanoma skin cancer. Secondary outcomes included all cancer except thyroid cancer, 16 cancer subtypes, and all-cause mortality. Results: Among 1 183 999 individuals in 11 databases, 909 168 individuals (mean age, 56.1 years; 507 316 [55.8%] women) were identified as new users of ranitidine, and 274 831 individuals (mean age, 58.0 years; 145 935 [53.1%] women) were identified as new users of other H2RAs. Crude incidence rates of cancer were 14.30 events per 1000 person-years (PYs) in ranitidine users and 15.03 events per 1000 PYs among other H2RA users. After PS matching, cancer risk was similar in ranitidine compared with other H2RA users (incidence, 15.92 events per 1000 PYs vs 15.65 events per 1000 PYs; calibrated meta-analytic hazard ratio, 1.04; 95% CI, 0.97-1.12). No significant associations were found between ranitidine use and any secondary outcomes after calibration. Conclusions and Relevance: In this cohort study, ranitidine use was not associated with an increased risk of cancer compared with the use of other H2RAs. Further research is needed on the long-term association of ranitidine with cancer development.

Chronic exertional compartment syndrome in adductor pollicis muscle: case report.

We report a case of chronic exertional compartment syndrome in the adductor pollicis that was confirmed by measuring elevated compartment pressure. Specific finding of magnetic resonance imaging, increased T2 signal intensity in the involved compartment, was also useful for the diagnosis. Pain was relieved by fasciotomy through a volar approach.

Total hip arthroplasty using cementless grit-blasted femoral component: a minimum 10-year follow-up study.

The grit-blasted cementless Spotorno (CLS) stem, which has excellent survival rates up to 10 years, is widely used in total hip arthroplasty (THA). We investigated the survivorships of CLS stems in THA at a minimum follow-up of 10 years and sought to identify factors that influence outcomes. A total of 227 hips of 191 patients who underwent cementless THA with a CLS stem were retrospectively reviewed at a mean follow-up of 12.3 years. All patients were evaluated clinically and radiographically according to implant type and surgery-related and patient-related factors. Survivorship was 97.2% when femoral revision for any reason was defined as the end point. Femoral revisions were performed in 3 hips because of periprosthetic fractures. Survivorship for all hips, using revision for any reason as the end point, was 92.6%. Two metal-on-metal THAs were revised because of aseptic loosening or osteolysis around the cup. No significant differences were evident for type of stem, type of bearing surface, stem alignment, or patient-related factors. However, a canal fill index of 80% or less was found to affect cortical remodeling, subsidence, and a change in stem position of 5° or more, which indicates that care must be taken not to undersize stems. In addition, in view of the revisions performed, bearing surfaces appear to importantly influence THA survivorship.

The cartilage degeneration and joint motion of bipolar hemiarthroplasty.

PURPOSE: The outcomes of bipolar hemiarthoplasty for osteonecrosis of femoral head have been disappointing due to cartilage degeneration and osteolysis. We investigated the cartilage degeneration, joint motion, and factors associated with osteolysis. METHODS: We retrospectively reviewed 134 bipolar hemiarthroplasties. The wear rate of acetabular cartilage was calculated. The ranges of motion of outer bearing and inner bearing were determined, and the ratio (O/I ratio) was calculated. RESULTS: The mean degeneration rate of acetabular cartilage was 0.34 ± 0.35 mm/year. We could observe that the outer bearing motion was dominant, but decreased over time. In addition, the degeneration rate of cartilage and the decline rate of outer bearing motion of the osteolysis group were significantly higher than those of the control group. CONCLUSIONS: Close observation is needed in cases of high degeneration rate of cartilage and rapid decline of outer bearing motion due to possibility of osteolysis.

Is bipolar hemiarthroplasty a reliable option for Ficat stage III osteonecrosis of the femoral head? 15- to 24-year follow-up study.

PURPOSE: The long-term results of a bipolar hemiarthroplasty (BHA) for osteonecrosis (ON) of the femoral head have not been favorable. The causes have been attributed to cup migration and osteolysis or groin pain. The purpose of this study was to analyze the long-term outcomes and the survivorships of bipolar hemiarthroplasty applied to Ficat stage III ON. MATERIALS AND METHODS: Between 1985 and 1993, 49 patients (63 hips) underwent cementless BHA for Ficat stage III ON. Of these 49 patients, 43 patients (55 hips) of mean age 42.2 years were available for follow-up review at a mean duration of 20.3 years post operation. Anteroposterior hip serial (including extreme abduction/adduction) radiographs were used to evaluate osteolysis, migration, cartilage wear rate, and the ratio of outer/inner bearing motion (O/I ratio) at the latest follow-up. RESULTS: The mean Harris hip score improved to 80.8 points at the latest follow-up. Survivorship at 24 years was 79 and 69 % with revision for any reason and development of acetabular osteolysis as the end point. Groin pain was present in 20 (36.4 %) of the 55 hips, and isolated groin pain was not a reason for revision. The patients had revision surgery performed, which showed that the cartilage wear rate was significantly high, and that the O/I ratio was significantly low (p < 0.05). CONCLUSION: Survivorship determined in this study was more favorable than that of previous studies, and exceeded expectation. The BHA for Ficat stage III ON is not reliable option anymore, considering low survival rate and high osteolysis developmental rate.