Risk factors for subchondral insufficiency fracture of the femoral head in renal transplant patients.

INTRODUCTION: Risk factors associated with subchondral insufficiency fracture (SIF) of the femoral head have not been established. The aim of the present study was to determine the incidence and risk factors for SIF of the femoral head following renal transplantation (RT). MATERIALS AND METHODS: We analyzed the cases of 681 RT patients (mean age at surgery: 49.5 ± 13.6 years, 249 women, 432 men) to determine the incidence of SIF. Hip magnetic resonance imaging (MRI) was performed 6 months post-RT. The following potential predictors of SIF were evaluated: (1) patient's condition at RT: bone mineral density (BMD), pre-RT laboratory values including calcium (Ca), phosphorus (P), calcium-phosphorus product (Ca × P), and intact parathyroid hormone; the patient and donor's blood relationship; and mismatching number of human leukocyte antigens (HLAs), and (2) post-RT dosage(s) of steroid(s), the immunosuppressive regimen, and the incidence of acute rejection. RESULTS: SIF was observed in 15 hips (13 patients, 1.9%). We successfully matched 39 patients without SIF. A multivariate logistic regression analysis adjusted for cumulative dosages of steroids, revealed the following were risk factors for SIF: osteoporosis (OR: 11.4, p = 0.046), lumbar BMD (OR: 0.003, p = 0.038), pre-RT serum P (OR 2.68, p = 0.004), and pre-RT serum Ca × P (OR: 1.11, p = 0.005). CONCLUSION: Since osteoporosis, the lumbar BMD, serum P, and serum Ca × P were identified as risk factors for a post-RT SIF, these factors should be evaluated before RT for the prediction of the SIF risk.

Effects of additional neck cut of the femur on the range of motion in total hip arthroplasty for hip dislocation: a computer simulation study.

BACKGROUND: Subtrochanteric shortening osteotomy (SSO) is commonly performed in total hip arthroplasty (THA) for high hip dislocation. However, this procedure is technically difficult and includes complications. Additional neck cut (ANC) of the femur is a procedure that involves femoral shortening by possibly eliminating the need for SSO in THA for high hip dislocation. Herein, we evaluated the effect and the depth limit of ANC of the femur on the range of motion (ROM) in THA for high hip dislocation. METHODS: ROM was measured in 26 patients with high hip dislocation using computer software. The stem was deeply positioned at 5-mm intervals from 0 mm to 30 mm (7 groups). The ROM before impingement was measured during flexion, internal rotation (IR) at 90° flexion, external rotation (ER) and abduction. Receiver operator coefficient (ROC) curves for abduction were generated. The cut-off value of ANC where the required ROM was achieved was also determined. RESULTS: Deeper ANCs increased the ROM values during flexion and IR, but they decreased the ROM values during ER and abduction. The ROM values during ER were also limited in 0-mm ANCs. According to the result of the ROC curve for abduction, 15 mm was considered as the permissible range of ANC. CONCLUSIONS: In THA for high hip dislocation additional neck cut should be taken into consideration for hips requiring less than 15-mm shortening. For more extended corrections a subtrochanteric shortening osteotomy should be performed.

Low energy irradiation of narrow-range UV-LED prevents osteosarcopenia associated with vitamin D deficiency in senescence-accelerated mouse prone 6.

Deficiency of vitamin D is an important cause of osteosarcopenia. The purpose of this study is to examine the effects of low energy narrow-range UV-LED on osteosarcopenia in animal models of senescence-accelerated mouse prone 6 (SAMP6). Preliminary experiments specified the minimum irradiance intensity and dose efficacy for vitamin D production (316 nm, 0.16 mW/cm2, 1,000 J/m2). we set a total of 4 groups (n = 8 per group); vitamin D-repletion without UV irradiation (Vit.D+UV-), vitamin D-repletion with UV irradiation (Vit.D+UV +), vitamin D-deficiency without UV irradiation, (Vit.D-UV-), and vitamin D-deficiency with UV irradiation (Vit.D-UV +). Serum levels of 25(OH)D at 28 and 36 weeks of age were increased in Vit.D-UV+ group as compared with Vit.D-UV- group. Trabecular bone mineral density on micro-CT was higher in Vit.D-UV+ group than in Vit.D-UV- group at 36 weeks of age. In the histological assay, fewer osteoclasts were observed in Vit.D-UV+ group than in Vit.D-UV- group. Grip strength and muscle mass were higher in Vit.D-UV+ group than in Vit.D-UV- group at 36 weeks of age. Signs of severe damage induced by UV irradiation was not found in skin histology. Low energy narrow-range UV irradiation may improve osteosarcopenia associated with vitamin D deficiency in SAMP6.

Incidence and risk factors for osteonecrosis of the hip in renal transplant patients: a prospective single-centre study.

BACKGROUND: There is a lack of evidence about the risk factors associated with osteonecrosis of the femoral head (ONFH). PURPOSES: To determine the incidence and risk factors for ONFH following renal transplantation (RT). METHODS: In total, data of 681 RT patients (mean age at surgery, 49.5 ± 13.6 years; 249 women and 432 men) were evaluated to determine the incidence of ONFH. Hip magnetic resonance imaging (MRI) was performed six months after RT. The following potential predictors of ONFH were evaluated: (1) patient's condition at RT; laboratory test results including calcium (Ca), phosphorus (P), calcium-phosphorus product (Ca × P), and intact parathyroid hormone before RT; blood relationship between the patient and donor; and mismatching number of human leukocyte antigens (HLAs), especially HLA class I and class II and (2) dosages of steroids after RT, immunosuppressive regimen, and incidence of acute rejection. RESULTS: ONFH was observed in 30 hips (21 cases, 3.1%). We successfully matched 63 patients without ONFH. Multivariate logistic regression analysis, adjusted for cumulative dosages of steroids, revealed that mismatching number of HLA (hazard ratio [HR], 1.61; 95% confidence interval [CI], 1.10-2.36; p = 0.014), HLA class II (HR, 3.73; 95% CI, 1.46-9.56; p = 0.001), P before RT (HR, 1.62; 95% CI, 1.02-2.58; p = 0.041), and Ca × P  before RT (HR, 1.06; 95% CI, 1.01-1.11; p = 0.024) were risk factors for ONFH. CONCLUSION: A greater number of HLA mismatches, HLA class II, serum P, and serum Ca × P were risk factors for ONFH after RT. Therefore, these factors should be evaluated in order to predict ONFH after RT.

Comparison of Wear Rate between Ceramic-on-Ceramic, Metal on Highly Cross-linked Polyethylene, and Metal-on-Metal Bearings.

Objective Currently, there is a lack of evidence on the medium-term follow-up of cementless total hip arthroplasty (THA) using metal on highly cross-linked polyethylene (MoP), ceramic-on-ceramic (CoC), and metal-on-metal (MoM) bearings. Our aim was to calculate the 5- to 10-year wear rate and the incidence rate of osteolysis for 3 types of bearings. Methods A total of 77 patients underwent MoP, 105 underwent ceramic CoC, and 55 underwent MoM THAs. The average patient age at the time of surgery was 64.7, 55.9, and 59.9 years old in the MoP, CoC, and MoM bearings, respectively. Clinical and radiologic measurements at a mean follow-up of 7.6 years were analyzed. Results The mean postoperative Harris hip scores showed no difference among the groups. The mean annual liner wear rates were 0.0160, 0.0040 and 0.0054 mm/year in MoP, CoC bearings, and MoM bearings, with that of CoC bearings being significantly lower than the others. Osteolysis (14.5%) among MoM bearings was significantly more frequently observed compared with the others. Kaplan-Meier survival at 10 years with implant loosening, or revision THA as the endpoint, was 96.1% (95% confidence interval [CI]: 88.4-98.7) for MoP, 98.6% (95% CI: 90.3-98.6) for CoC bearing, and 98.2% (95% CI: 88.0-99.7) for MoM bearings ( p = 0.360). Conclusion Excellent clinical and radiological outcomes were obtained for MoP and CoC bearings.

Comparison of Wear Rate between Ceramic-on- Ceramic, Metal on Highly Cross-linked Polyethylene, and Metal-on-Metal Bearings / Comparação da taxa de desgaste entre componentes de cerâmica sobre cerâmica, de metal sobre polietileno de alta ligação cruzada e de metal sobre metal

Abstract Objective Currently, there is a lack of evidence on the medium-term follow-up of cementless total hip arthroplasty (THA) using metal on highly cross-linked polyethylene (MoP), ceramic-on-ceramic (CoC), and metal-on-metal (MoM) bearings. Our aim was to calculate the 5- to 10-year wear rate and the incidence rate of osteolysis for 3 types of bearings. Methods A total of 77 patients underwent MoP, 105 underwent ceramic CoC, and 55 underwent MoM THAs. The average patient age at the time of surgery was 64.7, 55.9, and 59.9 years old in the MoP, CoC, and MoM bearings, respectively. Clinical and radiologic measurements at a mean follow-up of 7.6 years were analyzed. Results The mean postoperative Harris hip scores showed no difference among the groups. The mean annual liner wear rates were 0.0160, 0.0040 and 0.0054 mm/year in MoP, CoC bearings, and MoM bearings, with that of CoC bearings being significantly lower than the others. Osteolysis (14.5%) among MoM bearings was significantly more frequently observed compared with the others. Kaplan-Meier survival at 10 years with implant loosening, or revisionTHA as the endpoint, was 96.1% (95% confidence interval [CI]: 88.4-98.7) forMoP, 98.6% (95% CI: 90.3-98.6) for CoC bearing, and 98.2% (95% CI: 88.0-99.7) for MoM bearings (p = 0.360). Conclusion Excellent clinical and radiological outcomes were obtained for MoP and CoC bearings.

Resumo Objetivo Hoje, não há evidências sobre o acompanhamento em médio prazo da artroplastia total do quadril (ATQ) não cimentada com componentes de polietileno de alta ligação cruzada (highly cross-linked) sobre metal (MoP, na sigla em inglês), de cerâmica sobre cerâmica (CoC, na sigla em inglês), e de metal sobre metal (MoM, na sigla eminglês). Nosso objetivo foi calcular a taxa de desgaste entre 5 a 10 anos e a taxa de incidência de osteólise nos 3 tipos de componentes. Métodos Um total de 77 pacientes foram submetidos a ATQ com componentes de MoP; 105 foram submetidos ao mesmo procedimento com componentes de CoC, e 55 foram submetidos à ATQ com componentes de MoM. A média de idade dos pacientes no momento da cirurgia foi de 64,7, 55,9 e 59,9 anos nos grupos de componentes MoP, de CoC, e de MoM, respectivamente. Asmedidas clínicas e radiológicas emumperíodo médio de acompanhamento de 7,6 anos foram analisadas. Resultados As pontuações médias de Harris no período pós-operatório não mostraram diferença entre os grupos. As taxas médias anuais de desgaste do revestimento foram de 0,0160, 0,0040 e 0,0054 mm/ano em componentes de MoP, de CoC, e de MoP, respectivamente; a taxa de desgaste dos componentes de CoC foi significativamente menor do que as dos demais. A osteólise (14,5%) nos componentes de MoM foi significativamente mais frequente em comparação aos demais. A sobrevida de Kaplan- Meier aos 10 anos comafrouxamento do implante ou revisão da ATQ como desfecho foi de 96,1% (intervalo de confiança [IC] de 95%: 88,4-98,7) nos componentes de MoP, de 98,6% (IC95%: 90,3-98,6) nos componentes de CoC, e de 98,2% (IC95%: 88,0-99,7) nos componentes de MoM (p = 0,360). Conclusão Os resultados clínicos e radiológicos de componentes de MoP e de CoC foram excelentes.

What factors predict ceramic liner malseating after ceramic-on-ceramic total hip arthroplasty?

BACKGROUND: There is a lack of evidence about the risk factors associated with the malseating of the acetabular liner after ceramic-on-ceramic (CoC) total hip arthroplasty (THA). Therefore, we performed a complementary retrospective case-control study to determine the factors predicting the malseating of the acetabular liner after CoC THA and to evaluate the relationship between malseating and (1) osteoarthritis, (2) particularly in terms of the new radiographic parameter "bone sclerotic length" of the acetabular bone. HYPOTHESIS: Osteoarthritis, particularly bone sclerotic length, was an independent risk factor for malseating of ceramic liners. PATIENTS AND METHODS: In total, 219 CoC THAs (174 women and 45 men) were evaluated to determine the risk factors influencing the malseating of the acetabular ceramic liner. An average patient age at the time of surgery was 55.9±9.5 years (range, 23 to 75 years). Data on patient background and preoperative radiographs, such as Tönnis grades; Crowe classification; and indices of acetabular osteoarthritis change; including bone cyst, osteophyte and bone sclerosis, were assessed. The bone sclerotic length in patients with osteoarthritis was measured as the slant distance between the bilateral edges of the sclerosis lesion of the acetabulum on the anteroposterior view. RESULTS: Preoperative less hip flexion (hazard ratio [HR]: 0.98; 95% CI: 0.97-0.99), osteoarthritis (HR: 3.15; 95% CI: 1.02-9.70) and the bone sclerotic length (HR: 1.83; 95% CI: 1.35-2.48) were independent risk factors determining the malseating of ceramic liners. Receiver operating characteristic curve analysis showed that a bone sclerotic length of 24.6mm was defined as the cut-off point for the malseating of the ceramic liner. DISCUSSION: Age, preoperative less flextion, osteoarthritis, and the bone sclerotic were independent risk factors determining malseating of ceramic liners. The acetabular shell can also deform upon insertion of the cup with sclerotic bone of the acetabulum and prevent correct seating of liners. Therefore, these factors must be taken into consideration when seating the ceramic liner. LEVEL OF EVIDENCE: Case control study III, case control retrospective design.

32-mm ceramic-on-ceramic total hip arthroplasty versus 28-mm ceramic bearings: 5- to 15-year follow-up study.

INTRODUCTION:: This study aimed to compare the clinical and radiographic results of 28-mm ceramic-on-ceramic (CoC) total hip arthroplasty (THA) to those of 32-mm CoC during a 5- to 15-year follow-up period. METHODS:: 107 joints (95 women and 6 men) underwent 28-mm CoC, and 60 (49 women and 7 men) underwent 32-mm CoC. The average patient age at the time of surgery was 56.1 and 55.7 years in the 28-mm and 32-mm CoC groups, respectively. Clinical and radiologic measurements of all patients were analysed. RESULTS:: The mean preoperative Harris hip score (HHS) was similar in the 2 groups (28-mm, 58.9; and 32-mm, 58.5). However, at final follow-up, the mean HHS of the 32-mm CoC (91.8) was significantly better than that of the 28-mm CoC (88.2) ( p = 0.003), as were the ranges of motion (ROM) for flexion (98.3 ± 13.5° vs. 87.3 ± 19.3°, p < 0.001) and abduction (27.8 ± 14.9° vs. 22.1 ± 19.3°, p = 0.007). The mean wear rate was 0.0044 mm/year for the 28-mm CoC and 0.0044 mm/year for the 32-mm CoC. No ceramic fractures were found in the 2 groups. One joint in the 28-mm CoC (0.9%) required revision owing to progressive osteolysis. Kaplan-Meier survival at 10 years, with implant loosening or revision THA as the endpoint, was 98.3% for 28-mm CoC and 100% for 32-mm CoC ( p = 0.465). CONCLUSION:: There was no significant difference in ceramic-related complications between the 2 groups. Our study demonstrated that the 32-mm and 28-mm CoC are safe and are associated with good clinical outcomes.

Same survival but higher rate of osteolysis for metal-on-metal Ultamet versus ceramic-on-ceramic in patients undergoing primary total hip arthroplasty after 8 years of follow-up.

BACKGROUND: To avoid wear-induced osteolysis, ceramic-on-ceramic (CoC) and metal-on-metal (MoM) bearings have been developed. At present, there are no direct material related clinical comparisons between cementless total hip arthroplasty with CoC and MoM at more than 5-year follow-up. The bearing that is more likely to prevent osteolysis is still controversial. Therefore, we performed a retrospective case control study evaluating CoC and MoM cementless THAs in order to: - compare the longevity and complications for CoC and MoM THAs at 5-10 years postoperatively; - compare the incidence of osteolysis between both type THAs; - evaluate pseudotumors in MoM THAs. HYPOTHESIS: CoC THAs will have a lower rate of osteolysis, better longevity, and better clinical outcomes than MoM THAs. PATIENTS AND METHODS: Ninety-six hips underwent CoC THAs, and 56 hips underwent MoM THA (Ultamet, Pinnacle, Depuy). Average patient age at the time of surgery was 57.1 years (range, 28 to 77 years). RESULTS: There were no differences with regard to the Harris hip score (89.5 and 90.3 for the CoC and MoM groups, respectively). Osteolysis (9 hips, 14.3%) among MoM THAs were significantly more frequently observed compared to CoC THAs (2 hips, 2.1%). Kaplan-Meier survival at 8 years with implant loosening or revision THA as the endpoint was 98.2% (95% CI: 87.8-99.8) for CoC, and 98.6% (95% CI: 90.2-99.8) for MoM (p=0.684). There was one audible squeaking (1.0%) and no ceramic fracture among CoC THAs. Five (8.9%) hips showed pseudotumors among MoM THAs. DISCUSSION: CoC THAs had a low incidence of osteolysis. No significant difference was seen in the 8-year survival rate between implants, when using implant loosening and revision THA as endpoints. These data indicate that CoC THAs have excellent clinical and radiological outcomes, compared with MoM THAs. Ultamet MoM had a higher rate of osteolysis compared to other MoM bearings; the cup modularity (without polyethylene) and the use of 36mm heads as well as the process of production (after 2006) may play a significant role in the higher rate of osteolysis. LEVEL OF EVIDENCE: III, Case control study, case control retrospective design.

A Possible New Radiographic Predictor of Progression of Osteoarthritis in Developmental Dysplasia of the Hip: The Center Gap.

BACKGROUND: Patients with comparable severities of developmental dysplasia of the hip (DDH) may variably progress to osteoarthritis (OA) over time. Although joint congruency may be associated with OA progression in patients with DDH, it has only been assessed subjectively. We assessed the gap between the rotational centers of the acetabulum and femoral head (center gap) as a possible predictive measure of OA progression in patients with DDH. QUESTIONS/PURPOSES: In patients with bilateral DDH, we asked: (1) What is the probability of OA progression (Tönnis grade) or symptom development (pain) in the asymptomatic contralateral hip of patients with DDH undergoing unilateral joint-preserving surgery? (2) Is the center gap measurement associated with OA progression or symptom development in these hips? (3) Is the center gap measurement correlated with previous radiographic parameters? METHODS: A total of 297 patients (319 hips) underwent unilateral eccentric rotational acetabular osteotomy at our institution between July 1989 and December 1999. We performed no other joint-preserving surgery to treat patients with DDH during this timeframe. The inclusion criteria for the study were patients younger than 55 years of age, the contralateral hip classified as Tönnis Grade 0, no previous surgical interventions, and asymptomatic at the time of eccentric rotational acetabular osteotomy (155 patients, 155 hips). The exclusion criteria were a contralateral hip without dysplasia (four patients, four hips), loss to followup before 10 years (42 patients, 42 hips [27%]), or missing medical records or radiographs (21 patients, 21 hips [14%]). The remaining 88 patients (88 hips; 11 males and 77 females) with a mean age of 39 years (range, 17-53 years) and mean followup of 20 years (range, 10-27 years) were analyzed. From the institutional database, radiographic parameters including the center gap in the AP view were assessed using radiographs at the time of eccentric rotational acetabular osteotomy, and the Tönnis grade was recorded 1 year postoperatively and annually thereafter retrospectively. We defined migration of the rotational center of the femoral head based on the rotational center of the acetabulum in the horizontal plane as center gap X (mm) and in the vertical plane as center gap Y (mm) and defined the absolute value between the centers as center gap distance (mm). Using κ statistics, intra- and interobserver reliabilities were determined to be 0.896 and 0.857 for center gap X, 0.912 and 0.874 for center gap Y, and 0.912 and 0.901 for the center gap distance, respectively. When patients reported any contralateral ipsilateral hip pain during clinic visits, the hip was considered symptomatic. Kaplan-Meier survivorship analyses were performed with OA progression or symptom development in the nonoperative hip as the endpoint. Multivariate analyses were performed to assess risk factors for each outcome using the Cox proportional hazards model. Correlation analyses between the center gap and other parameters including lateral center-edge angle, femoral head extrusion index, acetabular depth-to-width index, femoral head lateralization, minimum width of the joint space, head sphericity, and joint congruency were performed using Pearson's correlation coefficient. RESULTS: At 20 years postoperatively, the probability of OA progression in the nonoperative hip was 13% (95% confidence interval [CI], 7.1-22.1) and the probability of symptom development was 34% (95% CI, 24.7-46.1). The center gap X measurements in the groups with OA progression (lateral 2.0 ± 2.1 [SD] mm) or symptom development (lateral 0.9 ± 2.4 mm) took a more lateral direction than those in the group without OA progression (medial 0.4 ± 2.1 mm) or symptom development (medial 0.5 ± 2.0 mm) (OA progression, p < 0.001; symptom development, p = 0.005). The center gap Y measurements in the groups with OA progression (distal 2.7 ± 7.1 mm) or symptom development (distal 2.1 ± 6.0 mm) took a more distal direction than those in the group without OA progression (proximal 1.6 ± 6.2 mm) or symptom development (proximal 2.5 ± 6.1 mm) (OA progression, p = 0.027; symptom development, p = 0.001). Independent risk factors for OA progression were the femoral head extrusion index (hazard ratio [HR], 1.11; 95% CI, 1.01-1.22; p = 0.028) and the center gap X (HR, 1.52; 95% CI, 1.07-2.16; p = 0.019), whereas no independent risk factors for symptom development were found. The center gap in the horizontal plane had no correlations with any other radiographic parameter studied. CONCLUSIONS: The center gap in the horizontal plane had a modest association with OA progression in this group of patients with DDH. Future studies are needed to determine the normal value of the center gap for patients without DDH and to assess the center gap in lateral radiographic views. LEVEL OF EVIDENCE: Level IV, prognostic study.

Comparison of cementless total hip arthroplasty survivorship between metal-on-highly cross-linked polyethylene and ceramic on ceramic bearings: A case control study with a 5-9-year follow-up.

BACKGROUND: Currently, there is a lack of evidence on the medium-term follow-up of cementless total hip arthroplasty (THA) using metal-on-highly cross-linked polyethylene bearing (MoXPE), ceramic on ceramic bearing (CoC) at more than 5 years follow-up. Therefore, we performed a case control study to: compare the incidence rate of osteolysis; compare the longevity for both types of THAs, and to evaluate the wear rate of MoXPE THAs. HYPOTHESIS: CoC THAs will have a lower rate of osteolysis and better longevity than MoXPE THAs. PATIENTS AND METHODS: We performed a retrospective analysis of 77 MoXPE (68 women, 9 men) and 105 CoC (85 women, 20 men) THAs, with an average patient age at the time of surgery of 64.7 years (range, 27 to 76 years). The cohorts were matched according to sex, body mass index, or diagnosis of hip joint disease. Clinical and radiologic measurements were analyzed at a mean follow-up of 6.7 years (range, 5-9 years). RESULTS: There were no between-group differences with regard to the Harris hip score (87.0 [64.0-98.0] and 89.9 [70.0-100.0] for the MoXPE and CoC group, respectively) and the incidence rate of osteolysis (2.6% and 1.9%, respectively). Revision was required for 1 case for each THA type. The Kaplan-Meier survival at 8 years, using implant loosening or revision as the end-point of analysis, was 96.1% (95% confidence interval [CI], 90.0-99.3) for the MoXPE group and 98.9% (95% CI, 92.2-99.8) for the CoC group (p=0.189). The mean annual liner wear rate was 0.0160mm/year (range, 0.0050 to 0.0390mm/year) for the MoXPE THAs. DISCUSSION: There was no difference between CoC and MoXPE THAs in the incidence of osteolysis or in survival rate at 8 years post-surgery. Excellent clinical and radiological outcomes were obtained for both types of bearings. LEVEL OF EVIDENCE: III, Case control study, case control retrospective design.

Preoperative Canal Bone Ratio is Related to High-Degree Stress Shielding: A Minimum 5-Year Follow-Up Study of a Proximally Hydroxyapatite-Coated Straight Tapered Titanium Femoral Component.

BACKGROUND: Few studies have reported risk factors for stress shielding. We sought to evaluate clinical and radiographic outcomes of a proximally hydroxyapatite-coated straight tapered titanium femoral component stem during a minimum 5-year follow-up and identify factors associated with high-degree stress shielding. METHODS: A total of 156 total hip arthroplasties (n = 124; 98 women and 26 men; mean age, 56.5 years) with a minimum follow-up period of 5 years were included in the study. Clinical and radiologic measurements at follow-up (range, 5-16.3 years; mean, 10.2 years) were analyzed. RESULTS: The mean preoperative Harris Hip Score (HHS) was 56.6, and the mean HHS at the latest follow-up was considerably improved at 86.8. Stress shielding at the latest follow-up was low degree in 136 (87%) hips and high degree in 20 (13%) hips. On average, high-degree stress shielding occurred 9.9 years (5-14 years) after surgery. The results of Cox proportional hazard analysis showed that a canal bone ratio ≥ 0.49 was an independent risk factor for high-degree stress shielding (P = .0075; hazard ratio, 3.981). HHS at the latest follow-up was significantly lower in high-degree stress shielding than in low-degree stress shielding (80.7 and 87.7, respectively; P = .0030). CONCLUSION: Preoperative canal bone ratio ≥ 0.49 is independently associated with high-degree stress shielding. In addition, the number of cases with high-degree stress shielding significantly increased over time during a mean 10-year follow-up.

The poor quality and reliability of information on periacetabular osteotomy on the internet in Japan.

Although many patients use the internet to access health-related information, the quality and the reliability of the information is highly inconsistent. Periacetabular osteotomy (PAO) is one of the surgical procedures for hip dysplasia. However, medical information on PAO is limited on the internet. This study aims to evaluate the quality and reliability of information available on PAO on the internet in Japan. A web search was conducted on two search engines for the following terms: "hip osteotomy," "pelvic osteotomy," and "osteotomy for hip preservation" in Japanese. In total, we found 120 websites. To determine the quality and reliability of information on each website, we used the Health on the Net Foundation (HON) score, the Brief DISCERN score, and an osteotomy-specific content (OSC) score. After eliminating duplicate websites, we reviewed 49 unique websites. Only three websites (6.1%) had good reliability, as indicated by their HON scores. Twelve websites (24.4%) had good-quality information, as measured by their Brief DISCERN scores. As evaluated by their OSC scores, physician websites were found to be biased toward etiology and surgical indication and did not provide information on the complications of procedures. Non-physician websites were generally insufficient. The information about PAO on the internet is, therefore, unreliable and of poor-quality for Japanese patients.

Independent association of joint space narrowing, cyst formation and health-related quality of life of patients with hip osteoarthritis in Japan.

INTRODUCTION: This study clarified individual associations of joint space narrowing (JSN) and radiographic features (RF) of hip osteoarthritis (HOA), i.e., cyst and osteophyte formation and subchondral sclerosis, with quality of life (QOL) in Japanese HOA patients. METHODS: This cross-sectional study comprised 117 Japanese HOA patients (98 women, 17 men; mean age, 61.2 years). We recorded locations and the size of each RF and measured JSN on the acetabular side (Ace) or femoral head (FH). We evaluated pain with the Visual Analog Scale (VAS) and assessed QOL with the physical component summary (PCS) and mental component summary (MCS) of the Medical Outcomes Study Short Form-36. We compared QOL with/without the RF on the Ace, FH or both and analyzed relationships between each RF and VAS, PCS and MCS with linear regression analysis. We assessed independent associations of each RF with PCS and MCS with multiple regression analysis using various independent variables. RESULTS: VAS values with the cyst on the Ace only were significantly lower than those with the cyst at both locations. PCS values with the cyst on the Ace only were significantly higher than those for both locations. Independent associations existed for maximum cyst length on the Ace and FH with VAS and for JSN with PCS, but none existed for MCS. CONCLUSIONS: Our study suggested that the location and the size of the cyst formation were associated with both VAS and QOL in Japanese HOA patients. The JSN was independently associated with the PCS.

Incidence of Ceramic Liner Malseating After Ceramic-on-Ceramic Total Hip Arthroplasty Associated With Osteolysis: A 5- to 15-Year Follow-Up Study.

BACKGROUND: The aim of our study was to evaluate the clinical and radiographic outcomes of malseating of the acetabular liner in ceramic-on-ceramic total hip arthroplasty (THA). METHODS: Outcomes for 160 ceramic-on-ceramic THAs, contributed by 116 women and 39 men, were evaluated. Clinical and radiographic measurements were obtained over a 5- to 15-year follow-up for analysis. RESULTS: Liner malseating was identified in 20% of cases. Outcomes for 32 cases with liner malseating (group A) were compared to outcomes for 128 joints with correct liner seating (group B). The Harris hip score at the last follow-up was 90.1 for group A and 89.6 for group B. Osteolysis was identified in 5 cases in group A (15.6%), compared to 3 cases in group B (P < .001). No significant between-group differences were identified with regard to ceramic fracture, audible squeaking, loosening of components, and revision THA. The mean annual liner wear rate was comparable between groups, 0.0045 mm/y for group A and 0.0039 mm/y for group B. The 10-year Kaplan-Meier survivorship, based on an end point of revision THA, was 100% for group A and 99.0% for group B. CONCLUSION: Over a moderate-length follow-up of 5-15 years, malseating of the acetabular liner was not associated with negative clinical outcomes or THA survivorship. Malseating did increase the incidence of osteolysis, a risk factor for adverse effects. Long-term follow-up studies are needed to fully quantify the effects of malseating of the acetabular liner.

Significantly Poor Outcomes of Total Hip Arthroplasty After Failed Periacetabular Osteotomy.

BACKGROUND: Periacetabular osteotomy (PAO) is an effective treatment for preosteoarthritis and early osteoarthritis in young and active patients with hip dysplasia. However, conversion to total hip arthroplasty (THA) for failed PAO is difficult owing to morphologic changes. The objective of the present study was to investigate outcomes of patients who underwent THA for failed PAO. METHODS: We performed a case-control study. The participants were 48 patients (52 hips) who underwent THA after PAO (the osteotomy group); type of PAO was eccentric rotational acetabular osteotomy in 36 hips and rotational acetabular osteotomy in 16 hips. These patients had a mean age at surgery of 56.5 years and underwent postoperative follow-up for a mean period of 5.4 years. For the control group, after matching age, gender, and time of surgery, we included 96 patients (104 joints) who underwent primary THA for hip dysplasia. RESULTS: The 2 groups demonstrated no significant difference in the preoperative Harris Hip Score. However, the osteotomy group demonstrated a significantly poor Harris Hip Score at the last follow-up, with particularly low scores for gait and activity. The osteotomy group demonstrated significantly poor range of motion at the last follow-up. Although neither group had any cases of revision surgery, both groups had 1 case of postoperative dislocation. Considering socket placement in Lewinnek's safe zone, the osteotomy group had significantly poorer results compared to that obtained after primary THA. CONCLUSION: The therapeutic outcomes and socket positioning for THA after PAO were poorer compared to those of primary THA.

Significantly Lower Wear of Ceramic-on-Ceramic Bearings Than Metal-on-Highly Cross-Linked Polyethylene Bearings: A 10- to 14-Year Follow-Up Study.

BACKGROUND: This study aimed to retrospectively compare clinical and radiographic results between consecutive total hip arthroplasties (THAs) using ceramic on ceramic (CoC) and metal-on-highly cross-linked polyethylene (MoP), with >10 years of follow-up. METHODS: Sixty-seven patients (52 women and 15 men) underwent CoC THA, whereas 81 (67 women and 14 men) underwent MoP THA. The average patient age at the time of surgery was 54.0 years in the CoC group and 54.2 years in the MoP group. RESULTS: The mean postoperative Harris Hip Scores were 88.9 and 86.4 in the CoC and MoP groups, respectively (P = .063), and the mean annual liner rates of wear were 0.0043 and 0.0163 mm/year, respectively (P < .001). Osteolysis was observed on the femoral side of 1 joint (1.5%) in the CoC group and in 1 (1.2%) acetabular and femoral (1.2%) joint each in the MoP group. Three joints (3.7%) in the MoP group showed aseptic cup loosening, one of which (1.2%) required revision THA because of progression of the loosening. Revision THA was also required in 1 joint (1.5%) in the CoC group because of ceramic fracture. The Kaplan-Meier survival rate at 10 years with implant loosening or revision THA as the end point was 98.5% for CoC and 96.3% for MoP (P = .416). CONCLUSION: The wear rate of CoC implants was significantly lower than that of MoP implants. Kaplan-Meier survival at 10 years with implant loosening and revision THA as end points did not differ significantly between these implants.