The use of dual mobility acetabular cups in total hip replacement reduces dislocation rates in hip dysplasia patients.

Total hip replacement arthroplasty (THA) in hip dysplasia patients has a higher dislocation rate than in patients with simple hip osteoarthritis due to anatomical deformation. Therefore, to reduce postoperative THA dislocation is the challenge for arthroplasty surgeons. From 2015 to 2020, 1525 patients underwent THA performed by two surgeons at a single institution. A total of 152 patients involving 172 THAs were included. The patients were classified into dual-mobility (DM) and fixed-bearing (FB) acetabular cup groups. The occurrence of postoperative dislocation and functional evaluation of the hip joint, was analyzed before and after surgery using the modified Harris hip score(mHHS). There was no difference in the preoperative demographics and radiographic parameters between the groups. The incidence of postoperative hip dislocation was significantly lower in the DM group (DM 0% vs. FB 9.0%) (P value = 0.003). The mHHS showed no difference before surgery and after surgery (DM 91.80 vs FB 92.03). Treating hip dysplasia patients with THA using a dual-mobility acetabular cup can reduce postoperative dislocations, and could be used for the better management of these patients.

Safety of using a large femoral head on thin polyethylene for total hip arthroplasty based on different types of polyethylene.

The use of a large femoral head in total hip arthroplasty (THA) to stabilize and reduce the incidence of dislocation is on the increase, but concerns arise when combining them with small acetabular components due to potential mechanical failures in thin polyethylene (PE) liners. A single-institution, retrospective cohort study was conducted on 116 patients with minimum 2-year follow-up who received 36-mm femoral heads and acetabular components ≤ 52 mm, using either remelted highly cross-linked polyethylene (remelted HXLPE) or vitamin E-infused HXLPE (VEPE). Osteolysis and implant loosening were not observed in either group. Although a fracture of the PE liner was observed in each group (1.7%), the clinical outcomes were excellent, as the mean modified Harris Hip Score (mHHS) at the last follow-up was 93.5. Moreover, the mean linear wear rates measured by digital imaging software in both groups were low, with 0.035 mm/y in remelted HXLPE and 0.030 mm/y in VEPE. In conclusion, The use of a large femoral head on a thin PE liner can be a viable treatment option in patients who need to prioritize stability; however, careful attention should be paid to mechanical fractures of the PE liner.

The usefulness of dual mobility cups in primary total hip arthroplasty patients at a risk of dislocation.

This study aimed to evaluate the early results of primary total hip arthroplasty (THA) using dual mobility (DM) cups in patients at a risk of dislocation and compare them with that of fixed bearing (FB) THA. This retrospective study included patients who had undergone primary THA between January 2016 and December 2018 and were at a risk of dislocation. A propensity score-matched analysis was conducted for 63 THA procedures with vitamin-E infused highly cross-linked polyethylene (VEPE) DM bearing and 63 THA procedures performed with FB from the same manufacturer for a mean follow-up period of 3.1 and 3.5 years, respectively. The radiologic outcomes at the last follow-up and incidence of postoperative complications were evaluated and compared statistically between the two groups. The modified Harris hip score (mHHS) was used to assess patient-reported outcomes. Postoperative dislocation occurred in 4 cases (6.3%) in the FB group, but did not occur in the DM group (p = 0.042). There was no difference in the radiologic outcomes and postoperative complications between the two groups. The mHHS at the last follow-up showed satisfactory outcomes in both the groups (DM group, 90.5; FB group, 88.1), without a statistical difference between the groups. The early results of THA using VEPE DM bearing showed better outcomes than that of THA with FB for patients at a risk of dislocation. A longer follow-up period is recommended to assess the stability and overall outcomes.

Early unexpected failure of a vitamin E-infused highly cross-linked polyethylene liner: A case report.

RATIONALE: Total hip arthroplasty (THA) with a polyethylene (PE) liner is 1 of the most effective and successful treatment strategies for end-stage hip disorders. Vitamin E-infused highly cross-linked polyethylene is theoretically known to prevent failure due to oxidative degradation in the body, and is resistant to wear; therefore, successful long-term survival of THA is expected. PATIENT CONCERNS: In June 2019, approximately 1.5 years after THA, the patient sat down and stood up without any specific issue; however, an unusual bullet sound occurred around the left hip joint. Since then, his discomfort persisted, and he was admitted to the emergency department. DIAGNOSIS: Plain radiography and metal artifact reduction computed tomography performed in the emergency department revealed eccentric elevation of the prosthetic femoral head and suspected PE liner failure. INTERVENTION: Revision surgery was performed for modular component exchange. To reduce the dislocation risk without performing cup exchange, conversion to dual-mobility articulation was performed. OUTCOMES: During the regular follow-up post-surgery, the patient could perform daily life activities without any discomfort, and dislocation was not observed. At 2 years postoperatively, no significant changes were observed in the radiographic images. LESSONS: This case report presents an unexpected failure of THA due to superior rim fracture and excessive wear at the locking mechanism of the vitamin E-infused highly cross-linked polyethylene liner. This is an interesting case, as early PE liner failure occurred without strong labor intensity or trauma. A modular component exchange was performed with a dual-mobility bearing, and no issues were observed approximately 2 years after the reoperation. Therefore, third-generation highly cross-linked polyethylene liners can also cause early failure without a clear cause, and this case report highlights the necessity of considering several strategies for reoperation. STUDY DESIGN: Case report.

Incidence and risk factors for failure of conservative treatment for valgus impacted femoral neck fractures in elderly patients with high-risk comorbidities-A bi-center retrospective observational study.

BACKGROUND: -Establishing the ideal indications for conservative treatment for elderly patients with valgus impacted femoral neck fractures is difficult because few studies have identified predictive factors for the failure of this treatment method. This study aimed to report the outcomes of conservative treatment for elderly patients with valgus impacted femoral neck fractures and determine risk factors that lead to treatment failure. METHODS: -From January 2009 to December 2018, 206 patients with valgus impacted femoral neck fracture were identified at two institutions. Elderly patients with valgus impacted femoral neck fractures corresponding to an Orthopedic Trauma Association/AO Foundation (OTA/AO) classification of 31-B1.1 or 31-B1.2 who were treated conservatively were included in the study. The following data was collected to compare the preoperative characteristics of patients with valgus impacted femoral neck fractures: age, sex, bone mineral density, medical comorbidities (hypertension, diabetes mellitus, ischemic heart disease, arrhythmia, chronic kidney disease [CKD], and stroke), medial cortex displacement, valgus angle, posterior tilt, and retroversion. These data were used to assess the independent predictors for failure of conservative treatment using multiple logistic regression analysis. RESULTS: -The failure rate after conservative treatment for valgus impacted femoral neck fracture in the enrolled patient group was 27.3% (15 of 55). CKD, presence of medial cortex displacement, high posterior tilt, and high retroversion were all identified as independent predictors for failure. The cut-off values for retroversion and posterior tilt that predicted treatment failure were 12.5° (area under curve [AUC] 0.768, p = 0.002, 95% confidence interval [CI] 0.632-0.903, sensitivity 0.733, 1-specificity 0.300) and 7.5° (AUC 0.712, p = 0.016, 95% CI 0.542- 0.881, sensitivity 0.667, 1-specificity 0.325), respectively. CONCLUSIONS: -The present study showed that a high union rate could be obtained if the indications for conservative treatment in for elderly patients with valgus impacted femoral neck fractures are well-defined. Thus, we believe that conservative treatment can be a viable option for valgus impacted femoral neck fractures when elderly patients with high-risk comorbidities have acceptable fracture angulation, no medial cortex displacement, and no CKD. LEVEL OF EVIDENCE: -Level III, retrospective cohort study.

High conversion rate to total hip arthroplasty after hemiarthroplasty in young patients with a minimum 10 years follow-up.

BACKGROUND: This study aimed to evaluate the follow-up results of bipolar hemiarthroplasty (BHA) for more than 10 years in patients aged < 60 years and to analyze the risk factors for acetabular erosion after BHA. METHODS: This retrospective study included 114 patients who underwent BHA were followed-up for at least 10 years. The mean age was 54.1 years, and the mean follow-up duration was 13.8 years. The patients were divided into two groups according to the presence of acetabular erosion, and the preoperative parameters were compared between the two groups. Moreover, the risk factors related to acetabular erosion after BHA were analyzed using statistical comparisons. RESULTS: Reoperation was performed in 44 of the 114 patients (38.6 %). The survival rate when the end point was reoperation related to acetabular erosion was found to be significantly time-dependent: 73.2 % at 5 years, 48.8 % at 10 years, and 25.9 % at 15 years. The acetabular erosion group showed significantly younger age at the time of surgery, higher body mass index (BMI), more avascular necrosis of the femoral head, and smaller prosthetic femoral head. The final multivariate logistic regression analysis showed that young age at the time of surgery were independent risk factors for acetabular erosion after BHA in patients aged < 60 years. CONCLUSIONS: The minimum 10-year follow-up outcomes of BHA in patients aged < 60 years showed a relatively high conversion rate to total hip arthroplasty. When considering BHA in younger patients, more careful decisions should be made with respect to patient's choice, keeping in mind that long-term survival cannot be guaranteed.

Wear and osteolysis outcomes for highly cross-linked polyethylene in primary total hip arthroplasty compared with conventional polyethylene: a 15- to 18-year single-centre follow-up study.

BACKGROUND: Although highly positive results for wear reduction of highly cross-linked polyethylene (HXLPE) have been reported around the 10-year follow-up, the long-term result related to reoperation and wear-related survival is still an issue. Therefore, this study aimed to compare the follow-up results of a single manufacture's polyethylene liner for >15 years in terms of survival and wear rate. METHODS: This retrospective cohort study included 134 primary total hip arthroplasties (THAs) who were followed up for at least 15 years. The mean age at the time of surgery was 50.7 years (conventional polyethylene [CPE] group = 22; HXLPE group = 112). Linear and volumetric wear rates of polyethylene were measured, and the reoperation rate and radiographic osteolysis were evaluated and Kaplan-Meier survival analysis was performed in both groups. Implant-related complications were also examined. RESULTS: HXLPE group showed a significantly lower wear rate in both linear and volumetric wear. None of the hip radiographs showed evidence of loosening or osteolysis in the HXLPE group. The survival rates at 15- to 18-year follow-up were 90.9% and 95.5% in the CPE and HXLPE groups when all-cause reoperation was the endpoint, and 90.9% and 100.0% when the wear-related reoperation was the endpoint, respectively. Implant-related complications were not different between the 2 groups. CONCLUSIONS: Wear reduction and osteolysis showed a great advantage in HXLPE after a 15-year follow-up. Although the CPE and HXLPE showed excellent survival, wear and osteolysis were more frequent in the CPE; therefore, the high risk of reoperation in the future should be considered.

Cementless total hip arthroplasty after failed internal fixation of acetabular fractures: A single center experience of 25 consecutive patients.

PURPOSE: Total hip arthroplasty (THA) is an available surgical option for failed acetabular fracture, previously managed by open reduction and internal fixation. This study aimed to report the postoperative outcomes of cementless THA in patients with this condition. MATERIALS AND METHODS: Between November 2000 and September 2016, 25 consecutive cementless THAs for failed internal fixation after acetabular fractures with a minimum follow-up of 2 years were analyzed. The mean age at the time of surgery was 58 years (36-85 years), and the time elapsed between fracture and THA was 70 months (7-213 months). Clinical and radiologic evaluations were performed on all patients. RESULTS: Clinically, the mean Harris hip score at the last follow-up was 88 points. Walking ability recovered to pre-injury status in 92% patients, and activities of daily living recovered in 96% patients. Radiographically, none of the acetabular cups showed evidence of migration and loosening during the mean follow-up of 50 months. All cases showed stable femoral stem fixation at the last follow-up. Dislocation occurred in three cases (12%). CONCLUSION: Outcomes of cementless THA after failed internal fixation for acetabular fractures were satisfactory. However, a relatively high incidence of postoperative dislocation is still a concern.

C-reactive protein for early detection of postoperative systemic infections in intertrochanteric femoral fractures.

BACKGROUND: This retrospective cohort study investigated perioperative C-reactive protein (CRP) value for early detection of postoperative systemic infective complications in elderly patients with intertrochanteric femoral fracture. METHODS: A total of 250 patients aged ≥65 years, with intertrochanteric femoral fractures that were surgically treated between January 2011 and December 2015 were included. CRP value was measured preoperatively and on postoperative day (POD) 3, 5, and 10, and analyzed with regard to postoperative systemic infections, delirium, and death within 1 year. The patients were divided into two groups according to postoperative systemic infection, and perioperative CRP responses between the two groups were comparedusing t-test (or Man-Whitney test where appropriate). The receiver operator characteristic (ROC) curves of CRP value were used to determine the best-supported cut-off values for identifying postoperative systemic infections. Systemic infections were reclassified as pulmonary and extra-pulmonary infections. RESULTS: The mean CRP values preoperatively and on POD 3, 5, and 10 were 2.82, 10.10, 3.74, and 1.89 mg/dL, respectively. Postoperative systemic infections, delirium, and death within 1 year were noted in 35 (14.0%), 30 (12.0%), and 45 (18.0%) patients, respectively. The CRP value in patients with postoperative systemic infections significantly elevated on POD 5 and 10 (p < 0.001, p < 0.001), and cut-off values were 4.71 and 1.59 mg/dL on POD 5 and 10, respectively. Postoperative delirium and death within 1 year were observed more often in the group with postoperative systemic infections (p = 0.003, p = 0.014). Although preoperatively elevated CRP values did not influence the postoperative CRP responses, they were significantly associated with delirium (p = 0.015). CONCLUSIONS: The CRP value on POD 5 is the earliest predictor of postoperative systemic infections in elderly patients with intertrochanteric femoral fractures that are managed surgically. Moreover, when the CRP value on POD 5 is >4.71 mg/dL, the possibility of postoperative systemic infections should be considered. LEVEL OF EVIDENCE: III, Retrospective cohort study.

Diagnostic strategy for elderly patients with isolated greater trochanter fractures on plain radiographs.

BACKGROUND: Isolated greater trochanter (GT) fractures are relatively rare and few studies have assessed the appropriate diagnostic and therapeutic strategies for these fractures. When initial plain radiographs show an isolated GT fracture, underestimation of occult intertrochanteric extension may result in displacement of a previously non-displaced fracture. This study examined the clinical results and value of different diagnostic strategies in elderly patients with isolated GT fractures on plain radiographs. METHODS: Between January 2010 and January 2015, 30 patients with initial plain radiographs showing isolated GT fractures were examined using MRI, bone scanning and/or CT for suspected occult intertrochanteric extension. We assessed the sensitivity, specificity, and positive and negative predictive value of each test. In addition, we noted the location of the fracture or soft-tissue injury on MRI in addition to treatment results. RESULTS: All 30 patients had osteoporosis and fractures caused by minor trauma. MRI revealed isolated GT fractures in nine patients and occult intertrochanteric fractures in 21 patients. Using the MRI-based diagnosis as a reference, the results showed that plain radiographs, bone scans, and CT scans can be used for supplementary examination but they are not appropriate as confirmatory tests for these fractures. However, in patients with both isolated GT fractures seen on plain radiographs and increased uptake in only the GT area on bone scans, MRI revealed isolated GT fractures. The fractures were treated surgically in 20 patients and conservatively in 10 patients with satisfactory clinical results. CONCLUSIONS: We confirmed that MRI-based examination is useful in all symptomatic elderly patients whose plain radiographic findings reveal isolated GT fractures. However, we suggest that there is a need to establish a diagnostic strategy through increased understanding of the available diagnostic methods. We believe that surgical treatment should be considered in patients with occult intertrochanteric fractures that are detected on MRI.

An Uncommon Case of Bilateral Pathologic Hip Fractures: Antiviral Drug-induced Osteomalacia in a Patient with Hepatitis B.

The long-term use of adefovir and tenofovir-antiviral medications commonly used to treat chronic hepatitis B-can be associated with proximal renal tubular dysfunction resulting in significant hypophosphatemic osteomalacia. However, there have been few reports about pathological fractures requiring surgical stabilization in cases of antiviral drug-induced hypophosphatemic osteomalacia. We present the case of a 51-year-old man who sustained bilateral pathological hip fractures associated with antiviral drug-induced hypophosphatemic osteomalacia. To treat a lamivudine-resistant hepatitis-B viral infection, the patient received adefovir for 7 years followed by tenofovir for the subsequent 3 years. He had suffered from polyarthralgia and generalized weakness for 2 years prior to presentation at our clinic. Misdiagnosis and inadequate management of his condition accelerated weakness of the bone matrix and ultimately induced pathological fractures. The patient was managed via cementless total hip arthroplasty on the left hip and internal fixation on the right hip. This case highlights that orthopaedic surgeons should consider the possibility of hypophosphatemic osteomalacia if patients receiving antiviral drugs complain of polyarthralgia and generalized weakness.

Subtle elbow instability associated with lateral epicondylitis.

BACKGROUND: In lateral epicondylitis, even in the absence of apparent instability, subtle instability can be found under anesthesia. We wanted to ascertain the following: (1) how many elbows surgically treated with lateral epicondylitis showed subtle instability during examination under anesthesia (EUA), (2) how effective magnetic resonance imaging (MRI) was in predicting subtle instability, and (3) if any difference existed in preoperative clinical data between elbows with and without subtle instability during EUA. METHODS: One hundred and twenty-two elbows (117 patients) diagnosed with intractable lateral epicondylitis underwent surgical treatment. No elbow showed apparent instability with conventional physical examination. Under general anesthesia, the elbows were examined for subtle instability via fluoroscopy and divided into unstable and stable groups. Potential prognostic factors and functional scores were assessed retrospectively. The MRIs were reviewed again by two radiologists. RESULTS: Seventeen elbows (unstable group, 13.9%) had subtle instability in EUA, while 105 elbows (stable group, 86.1%) did not. Lateral collateral ligament (LCL) complex injury was noted in the MRIs of 28 elbows. Fifteen elbows showed subtle instability among 28 elbows with abnormal MRI (positive predictive value, 53.6%), while 81 elbows did not show subtle instability among 82 elbows with normal MRI (negative predictive value, 98.7%). The preoperative visual analog scale score was higher in the unstable group than in the stable group (p < 0.001), and a history of multiple corticosteroid injections (≥3) was related to subtle instability in EUA (p = 0.042). Other factors showed no significant differences between both groups. CONCLUSIONS: Subtle instability resulting from LCL complex injury was noted in elbows with lateral epicondylitis. This could be visualized with fluoroscopic EUA, and preoperative MRI could be used to exclude subtle instability. Surgeons should consider checking for subtle instability, especially when patients have a history of multiple corticosteroid injections (≥3) or severe pain and MRI indicates instability.

Variations in sagittal locations of anterior cruciate ligament tibial footprints and their association with radiographic landmarks: a human cadaveric study.

BACKGROUND: This cadaveric study aimed to demonstrate variation of the anterior cruciate ligament (ACL) tibial attachment in the sagittal plane, and to analyze the radiographic landmarks which predict the sagittal location of the ACL tibial attachment. METHODS: In 20 cadaveric knees, native ACLs were removed and the centers of the ACL tibial and femoral attachments were marked with metal pins. Full extension lateral radiographs were then obtained in each cadaveric knee. Using the full extension lateral radiographs, the sagittal location of the ACL tibial footprint center was estimated as a percentage in the Amis and Jakob's line. Several radiographic landmarks including the geometry of Blumensaat's line and the apex of the tibial eminence were measured. Then, the relationship between the variation of the sagittal location of the ACL tibial footprint and several radiographic landmarks were analyzed using Pearson's correlation analysis. RESULTS: The average sagittal position of the native ACL tibial footprint was 40.9% (range: 38.0-45.0%). The line connecting the centers of the ACL footprint was nearly parallel to Blumensaat's line, with an average angle of 1.7° (range: 0-4.1°). In addition, the distance from the point where Blumensaat's line meets the tibial articular surface to the center of the ACL tibial footprint was almost consistent, at 7.6 mm on average (range: 6.4-8.7 mm). The correlation analysis revealed that the geometry of Blumensaat's line was significantly correlated with the sagittal location of the ACL tibial footprint. CONCLUSION: The radiographic landmark that showed a significant correlation with the ACL tibial footprint in the full extension lateral radiographs was Blumensaat's line.