Change of joint line convergence angle and other coronal alignments after total hip arthroplasty.

BACKGROUND: The purpose of this study was to determine the unloading effect of total hip arthroplasty (THA) on the ipsilateral knee joint through the joint line convergence angle (JLCA) change and determine the changes in other coronal radiographic parameters after THA, and evaluate the sensitivity of JLCA. PATIENTS AND METHODS: We retrospectively assessed 70 patients who underwent unilateral THA. Hip parameters such as neck shaft angle (NSA), neck length, and femoral offset and coronal alignment parameters of the lower extremity such as hip-knee-ankle angle (HKA), femur length, mechanical lateral distal femoral angle (mLDFA), JLCA, medial proximal tibial angle (MPTA), lateral distal tibial angle (LDTA), and plafond talus angle (PTA) were measured in the operative and non-operative sides. We compared all hip and coronal alignment parameters between before and 1 year after THA, and the amount of standardized changes (Δ) between all hip and coronal alignment parameters on the operative side, respectively. RESULTS: All mean hip and coronal alignment parameters on the operative side changed significantly 1-year after THA; however, those on the non-operative side did not. On the operative side, mean JLCA and PTA changed in the direction of closing the joint lateral space, from 1.81° and 0.47° to 1.22° and 0.11°, respectively (p<0.001 and 0.046, respectively). Mean NSA, HKA, and mLDFA changed in the valgus direction, from 129.39°, 2.62°, and 86.69° to 133.54°, 1.53°, and 85.91°, respectively (p<0.001). Mean femoral offset, neck length, and femur length increased from 36.45mm, 47.83mm, and 429.20mm to 39.85mm, 55.06mm, and 436.33mm, respectively (p<0.001). Mean MPTA and LDTA increased from 85.43° and 87.50° to 86.73° and 90.38, respectively (p<0.001). JLCA was more vulnerable to change than HKA, femur length, mLDFA, MPTA, and PTA (p<0.05). DISCUSSION: JLCA change on the operative side was more sensitive than changes of other coronal alignments after THA. According to the cohort, THA might have an unloading effect on the medial compartment of the knee joint. LEVEL OF EVIDENCE: IV; retrospective case-control and cohort studies.

Periprosthetic Occult Femoral Fracture: An Unknown Side Effect of Press-Fit Fixation in Primary Cementless Total Hip Arthroplasty.

Purpose: The objectives of this study were to examine the prevalence and risk factors for development of periprosthetic occult femoral fractures during primary cementless total hip arthroplasty (THA) and to assess the clinical consequences of these fractures. Materials and Methods: A total of 199 hips were examined. Periprosthetic occult femoral fractures were defined as fractures not detected intraoperatively and on postoperative radiographs, but only observed on postoperative computed tomography (CT). Clinical, surgical, and radiographic analysis of variables was performed for identification of risk factors for periprosthetic occult femoral fractures. A comparison of stem subsidence, stem alignment, and thigh pain between the occult fracture group and the non-fracture group was also performed. Results: Periprosthetic occult femoral fractures were detected during the operation in 21 (10.6%) of 199 hips. Of eight hips with periprosthetic occult femoral fractures that were detected around the lesser trochanter, concurrent periprosthetic occult femoral fractures located at different levels were detected in six hips (75.0%). Only the female sex showed significant association with an increased risk of periprosthetic occult femoral fractures (odds ratio for males, 0.38; 95% confidence interval, 0.15-1.01; P=0.04). A significant difference in the incidence of thigh pain was observed between the occult fracture group and the non-fracture group (P<0.05). Conclusion: Occurrence of periprosthetic occult femoral fractures is relatively common during primary THA using tapered wedge stems. We recommend CT referral for female patients who report unexplained early postoperative thigh pain or developed periprosthetic intraoperative femoral fractures around the lesser trochanter during primary THA using tapered wedge stems.

Does spinopelvic motion change after total hip arthroplasty?

PURPOSE: Spinopelvic motion plays an important role in functional acetabular cup position after total hip arthroplasty (THA). Sacral slope (SS) has been a useful surrogate for spinopelvic motion. The present study aimed to investigate statistical characteristics of spinopelvic motion before and after THA using changes in SS in supine, standing, and sitting positions. METHODS: A total of 76 patients (88 hips) were assessed. To classify spinopelvic mobility, defined as a change in SS from standing to sitting position (ΔSSstand/sit), 10° ≤ ΔSSstand/sit ≤ 30°, ΔSSstand/sit < 10°, and ΔSSstand/sit > 30° were considered normal, stiff, and hypermobile, respectively. RESULTS: Over ± 7° changes in SS between before and one year after THA were observed in 39 (44.3%) hips in the sitting position, 19 (21.6%) hips in the supine position, seven (7.9%) in the standing position. Percentages of hips with stiff spinopelvic mobility (11.4% vs. 22.7%) and hypermobile spinopelvic mobility (23.9% vs. 12.5%) between before THA and one year after THA were significantly different (p = 0.034 and p = 0.016, McNemar's test). At one year after THA, 40.0% (4/10) of hips with stiff spinopelvic mobility and 57.1% (12/21) of hips with hypermobile spinopelvic mobility shifted to normal spinopelvic mobility. CONCLUSIONS: Change in SS between before THA and one year after THA had a high inter-subject variability especially in the sitting position. In addition, there was a distinct shift to normal spinopelvic mobility postoperatively in hips with stiff and hypermobile spinopelvic mobility pre-operatively.

Periprosthetic occult acetabular fracture: an unknown side effect of press-fit techniques in primary cementless total hip arthroplasty.

BACKGROUND: This study sought to investigate the prevalence and risk factors of periprosthetic occult acetabular fracture occurring during cementless acetabular cup insertion in patients undergoing primary total hip arthroplasty (THA) and to assess the clinical consequences of these fractures. METHODS: A total of 232 hips (n = 205 patients) were included in this study. A periprosthetic occult acetabular fracture was defined as that which was unrecognised intraoperatively and was undetectable on post-operative radiographs yet was successfully diagnosed on post-operative computed tomography (CT) images. Clinical (age, sex, body mass index, and preoperative diagnosis) and surgical (additional screw fixation, cup rim size, and cup type) variables were analysed to identify risk factors for periprosthetic occult acetabular fracture. RESULTS: Sixteen (6.9%) periprosthetic occult intraoperative acetabular fractures were identified. In addition, one (0.4%) periprosthetic acetabular fracture was found during operation. The superolateral wall (9/16 hips; 56.3%) was the most frequent location. In addition, one (0.4%) periprosthetic acetabular fracture was found during operation. Male sex was the only factor associated with an increased risk for periprosthetic occult intraoperative acetabular fracture (odds ratio for male versus female sex: 4.28; p = 0.04). There was no significant association between cup type and the occurrence of periprosthetic occult acetabular fracture. All 16 hips with periprosthetic occult intraoperative acetabular fracture were healed at the final follow-up visit without the requirement for any additional surgical interventions. CONCLUSION: The results of the current study suggest that periprosthetic occult acetabular fractures are common during press-fit acetabular cup insertion in primary THA. Surgeons should have a high index of suspicion and early CT imaging referral in male patients who present with unexplained early post-operative groin pain in primary THA using cementless acetabular cups.

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

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

Total Hip Arthroplasty: Past, Present, and Future. What Has Been Achieved?

In the 1960s, Sir John Charnley introduced to clinical practice his concept of low-friction total hip arthroplasty (THA). Although early designs were plagued by poor performance and even failure, there have been steady advances in implant designs, biomaterials, surgical techniques and an understanding of the biomechanical restoration of the hip; these advances have contributed to improvements in implant survival and clinical outcomes of THA in the past three decades. With improved wear resistance and mechanical reliability, a potential to last for at least 25 to 30 years are now available for THA. In this review, we focus on the evolution of THA and review current controversies and future directions of this procedure based on a single surgeon's 29-year of experience at a single institution.

Differentiating Nutrient Artery Canals of the Femur versus Fracture Lines in Patients with Total Hip Arthroplasty on Plain Radiographs.

BACKGROUND: Nutrient artery canals of the femur are often visible on plain radiographs as radiolucent lines which may mimic fracture lines. The purpose of this study was to distinguish nutrient artery canals from fracture lines on plain radiographs. MATERIALS AND METHODS: Ninety-three patients (102 hips) with an average age of 65.6 years were included in the study. We retrospectively analyzed nutrient artery canals of the femur on pre and postoperative anteroposterior (AP) and cross-table lateral (CTL) hip radiographs in patients with cementless total hip arthroplasty. The shape, number, location, direction of obliquity, length of nutrient artery canal, and the distance between the tip of the greater trochanter and the proximal end of the nutrient artery canal were measured. RESULTS: Nutrient artery canals were determined in 54 hips (53.0%) on preoperative radiographs. The numbers of nutrient artery canals were entirely found to be one for each hip. The nutrient artery canals of the femur were the most frequently seen in the cortex on CTL radiographs with 32 hips (31.4%), whereas nutrient artery canals were not seen at all in the cortex on AP radiographs. All nutrient artery canals in the cortex on CTL radiographs coursed upward obliquely. Comparing to fracture lines, nutrient artery canals show less radiolucency, smaller diameter, and blunted ends in both the cortex and medullary cavity, show sclerotic walls in the cortex and have the less straight course in the medullary cavity. CONCLUSIONS: Based on the results of this study, there are clearly distinguishable differences between nutrient artery canals of the femur and fracture lines on plain radiographs.

Occult periprosthetic femoral fractures occur frequently during a long, trapezoidal, double-tapered cementless femoral stem fixation in primary THA.

The present study aimed to investigate the prevalence and clinical consequences of occult intra-operative periprosthetic femoral fractures in total hip arthroplasty (THA). Between 2012 and 2017, a total of 113 primary THAs were enrolled. The mean age of the patients was 66.4 ± 7.6 years. We assessed occult intra-operative periprosthetic femoral fractures with the use of computed tomography (CT) and risk factors, including age, sex, body mass index, diagnosis, stem size, and radiographic parameters of proximal femoral geometry were analyzed. We also assessed the differences in thigh pain and stem subsidence and alignment between the patients with and without occult periprosthetic femoral fracture. Occult intra-operative periprosthetic femoral fractures were found in 13 of 113 hips (11.5%). In 9/13 (69.2%) of occult fractures, fracture lines were started from the region below the tip of the lesser trochanter. Six periprosthetic femoral fractures (5.3%) were found during the operation. Out of the five hips that had detected femoral fractures around the lesser trochanter intra-operatively, four hips (80%) showed concurrent occult fractures on different levels. The female sex (P = .01) and canal filling ratio at 7 cm below the tip of the lesser trochanter (P = .01) were significantly different between the patients with and without occult periprosthetic femoral fracture. The sex was significantly associated with an increased risk in predicting an occult intra-operative periprosthetic femoral fracture (odds ratio of male, 0.25 compared with the female; 95% CI, 0.08-0.85; p = .02). There was a significant difference in the incidence of thigh pain between occult fracture group and non-occult fracture group (P < .05). There were no significant differences in stem subsidence and alignment between the patients with and without occult periprosthetic femoral fracture. All 13 cases of occult intra-operative periprosthetic femoral fractures were healed at the final follow-up. Occult periprosthetic femoral fractures are common during a long, trapezoidal, double-tapered cementless femoral stem fixation in primary THA, that CT scans are helpful to identify them, and that these fractures do not adversely affect the implant's survival if a rigid fixation of the implants has been achieved.

The Safe Zone Range for Cup Anteversion Is Narrower Than for Inclination in THA.

BACKGROUND: Cup malposition is a common cause of impingement, limitation of ROM, acceleration of bearing wear, liner fracture, and instability in THA. Previous studies of the safe zone based on plain radiographs have limitations inherent to measuring angles from two-dimensional projections. The current study uses CT to measure component position in stable and unstable hips to assess the presence of a safe zone for cup position in THA. QUESTIONS/PURPOSES: (1) Does acetabular component orientation, when measured on CT, differ in stable components and those revised for recurrent instability? (2) Do CT data support historic safe zone definitions for component orientation in THA? METHODS: We identified 34 hips that had undergone revision of the acetabulum for recurrent instability that also had a CT scan of the pelvis between August 2003 and February 2017. We also identified 175 patients with stable hip replacements who also had a CT study for preoperative planning and intraoperative navigation of the contralateral side. For each CT study, one observer analyzed major factors including acetabular orientation, femoral anteversion, combined anteversion (the sum of femoral and anatomic anteversion), pelvic tilt, total offset difference, head diameter, age, sex, and body mass index. These measures were then compared among stable hips, hips with cup revision for anterior instability, and hips with cup revision for posterior instability. We used a clinically relevant measurement of operative anteversion and inclination as opposed to the historic use of radiographic anteversion and inclination. The percentage of unstable hips in the historic Lewinnek safe zone was calculated, and a new safe zone was proposed based on an area with no unstable hips. RESULTS: Anteriorly unstable hips compared with stable hips had higher operative anteversion of the cup (44° ± 12° versus 31° ± 11°, respectively; mean difference, 13°; 95% confidence interval [CI], 5°-21°; p = 0.003), tilt-adjusted operative anteversion of the cup (40° ± 6° versus 26° ± 10°, respectively; mean difference, 14°; 95% CI, 10°-18°; p < 0.001), and combined tilt-adjusted anteversion of the cup (64° ± 10° versus 54° ± 19°, respectively; mean difference, 10°; 95% CI, 1°-19°; p = 0.028). Posteriorly unstable hips compared with stable hips had lower operative anteversion of the cup (19° ± 15° versus 31° ± 11°, respectively; mean difference, -12°; 95% CI, -5° to -18°; p = 0.001), tilt-adjusted operative anteversion of the cup (19° ± 13° versus 26° ± 10°, respectively; mean difference, -8°; 95% CI, -14° to -2°; p = 0.014), pelvic tilt (0° ± 6° versus 4° ± 6°, respectively; mean difference, -4°; 95% CI, -7° to -1°; p = 0.007), and anatomic cup anteversion (25° ± 18° versus 34° ± 12°, respectively; mean difference, -9°; 95% CI, -1° to -17°; p = 0.033). Thirty-two percent of the unstable hips were located in the Lewinnek safe zone (11 of 34; 10 posterior dislocations, one anterior dislocation). In addition, a safe zone with no unstable hips was identified within 43° ± 12° of operative inclination and 31° ± 8° of tilt-adjusted operative anteversion. CONCLUSIONS: The current study supports the notion of a safe zone for acetabular component orientation based on CT. However, the results demonstrate that the historic Lewinnek safe zone is not a reliable predictor of future stability. Analysis of tilt-adjusted operative anteversion and operative inclination demonstrates a new safe zone where no hips were revised for recurrent instability that is narrower for tilt-adjusted operative anteversion than for operative inclination. Tilt-adjusted operative anteversion is significantly different between stable and unstable hips, and surgeons should therefore prioritize assessment of preoperative pelvic tilt and accurate placement in operative anteversion. With improvements in patient-specific cup orientation goals and acetabular component placement, further refinement of a safe zone with CT data may reduce the incidence of cup malposition and its associated complications. LEVEL OF EVIDENCE: Level III, diagnostic study.

Changes in coronal alignment of the ankle joint after high tibial osteotomy.

PURPOSE: The purpose of this study was to investigate changes in coronal alignment of the ankle joint after HTO. Our hypothesis was that ankle joint orientation may become more parallel or less parallel to the ground after HTO, and this change may affect ankle symptoms. METHODS: Eighty-six knees were retrospectively analysed after HTO for varus osteoarthritis. Preoperative and follow-up whole-leg radiographs were taken. The hip-knee-ankle (HKA) angle and medial proximal tibial angle (MPTA) were measured to evaluate coronal alignment of the knee. Tibial plafond inclination (TPI), talar inclination (TI), talar tilt (TT), and lateral distal tibial angle (LDTA) were measured to evaluate coronal alignment of the ankle. Patients were divided into two groups: those who exhibited a decrease in the absolute value of TPI and TI after HTO (group A) and those who exhibited an increase in the absolute value of TPI or TI after HTO (group B). Clinical outcomes of the knee and ankle were evaluated pre- and postoperatively. RESULTS: Mean TPI and TI changed from 6.9° ± 3.6° and 8.0° ± 3.8° to 2.8° ± 3.1° and 3.9° ± 3.0° in group A (P < 0.001 for both) and from -1.3° ± 3.7° and 0.6° ± 4.5° to -6.0° ± 4.2° and -4.6° ± 5.9° in group B (P = 0.018 for both). VAS for ankle pain did not change significantly after HTO (n.s.) in group A, whereas those of group B increased significantly after HTO (P = 0.014). CONCLUSION: Ankle joint orientation becomes more parallel or less parallel to the ground after HTO. Smaller preoperative HKA and LDTA result in a more valgus ankle joint orientation after HTO. Ankle symptoms were affected by coronal alignment changes of the ankle after HTO. LEVEL OF EVIDENCE: III.

Use of auxiliary locking plates for the treatment of unstable pertrochanteric femur fractures.

Pertrochanteric femur fractures are successfully treated by orthopedic surgeons worldwide, but maintaining the reduction status or fixation of the greater trochanter is sometimes difficult in unstable cases in elderly patients. Several biomechanical advantages have been reported in locking plates when compared with conventional plates; locking plates provide angular and axial stability, better rigidity, and no toggling, and they preserve periosteal blood supply. The authors describe the use of auxiliary locking plates in unstable pertrochanteric femur fractures in elderly patients. Mini locking plates are simple, straightforward, and versatile enough to be used in elderly patients.

Navigated Acetabular Cup Fixation for Acetabular Deformity or Revision Total Hip Arthroplasty.

PURPOSE: To evaluate the usefulness of navigated acetabular cup fixation for total hip arthroplasty in patients with acetabular deformity or revision total hip arthroplasty. MATERIALS AND METHODS: This study enrolled 28 patients with at least 12 months' follow-up. The safe zone of the acetabular cup was defined as 40°±10°in inclination and 15°±10°in anteversion. The authors used the navigation and radiographic data to determine whether the acetabular cup was located within the safe zone or not. To evaluate the clinical outcomes, preoperative and last follow-up Harris hip scores were checked, and the occurrence of complications was evaluated. RESULTS: According to the navigation data, the mean inclination and anteversion were 38.5°±4.7°(range, 32°-50°) and 16.6°±4.0°(range, 8°-23°), respectively. According to the radiographic data the mean inclination and anteversion were 40.5°±4.6°(range, 32°-50°) and 19.4°±4.2°(range, 8°-25°), respectively. In both cases, all values were within the safe zone. Harris hip score was improved in all patients from preoperative 52.3±14.4 points (range, 29-87 points) to 88.0±9.0 points (range, 65-99 points) at the last follow-up. There was no dislocation or loosening of both cases. CONCLUSION: Navigated acetabular cup fixation is a useful technique for total hip arthroplasty in patients with acetabular deformity or revision total hip arthroplasty because it prevents the malposition and related complications.

Subtrochanteric femoral fracture during trochanteric nailing for the treatment of femoral shaft fracture.

We report on three cases of subtrochanteric femoral fractures during trochanteric intramedullary nailing for the treatment of femoral shaft fractures. Trochanteric intramedullary nails, which have a proximal lateral bend, are specifically designed for trochanteric insertion. When combined with the modified insertion technique, trochanteric intramedullary nails reduce iatrogenic fracture comminution and varus malalignment. We herein describe technical aspects of trochanteric intramedullary nailing for femoral shaft fractures to improve its application and prevent implant-derived complications.

Characterization of progression of pelvic osteolysis after cementless total hip arthroplasty: computed tomographic study.

A retrospective analysis of 63 primary total hip arthroplasty cases was done using repeated computed tomography scans to evaluate the pelvic osteolytic lesions in early stage. The progression rate of osteolysis of hips with small osteolytic volume less than 766.97 mm(3) in initial CT was 85.82 mm(3)/year, and that of hips with osteolysis more than 766.97 mm(3) was 456.3 mm(3)/year (P < 0.001). Younger patients less than 52 years old with good Harris Hip Scores (more than 80) frequently showed much faster progression in volume of osteolytic lesions. The rate of osteolysis was accelerated when the amount of osteolysis reached a certain threshold volume in active young patients in a cascade manner even in early stage.

Fifteen-year results of precoated femoral stem in primary hybrid total hip arthroplasty.

BACKGROUND: There has been controversy whether methylmethacrylate precoating of the cemented femoral stem is a solution for aseptic loosening or rather contributes to increased failure rates in cemented total hip arthroplasties. METHODS: On a retrospective basis, we analyzed 76 primary hybrid total hip arthroplasties from 63 patients with precoated, cemented femoral stems between October 1990 and December 1995. The mean age of the patients was 46.8 years (range, 22 to 77 years) with a minimum follow-up of 14 years (mean, 15.5 years; range, 14 to 19.5 years). Third generation cementing techniques were employed in all cases. RESULTS: Twenty-four out of 76 cases (31.6%) showed aseptic loosening of the femoral stems, of which 23 stems were revised at an average revision time of 8 years (range, 3 to 14.8 years). The main mode of loosening was cement-stem interface failure in 22 hips (91.7%). Twenty-one out of 24 failed hips (87.5%) demonstrated C2 cementing grades (p < 0.001). Kaplan-Meier survivorship analysis using radiographic aseptic loosening of the femoral stem as the endpoint for failure showed survival rates of 76.5% at 10 years (95% confidence interval [CI], 71.4 to 81.6) and 63.2% at 19 years (95% CI, 57.3 to 69.1). CONCLUSIONS: An early failure of the precoated femoral stem in this study was mainly due to an insufficient cementing technique. Achievement of good cement mantle may improve the survival rates.

A validation study for estimation of femoral anteversion using the posterior lesser trochanter line: an analysis of computed tomography measurement.

The aim of this study was to introduce a simple and reliable intraoperative reference guide to reproduce the normal femoral anteversion during total hip arthroplasty (THA). We hypothesized that the posterior lesser trochanter line (PLTL) could be a useful guide for estimating femoral anteversion during THA. We conducted a study of 56 men (112 hips) to evaluate the relationship between the PLTL and the femoral anteversion using computed tomography scans. The mean femoral anteversion was 9.0° ± 8.1° (range, -16.2° to 32.9°). The PLTL angle correlated (r(2) = 0.12, P < 0.05) with the femoral anteversion. We found a constant relationship between the PLTL and femoral anteversion, and the PLTL may be used as a guide for estimating the femoral stem anteversion during femoral stem fixation.

The use of the posterior lesser trochanter line to estimate femoral neck version: an analysis of computed tomography measurements.

We hypothesized that the lesser trochanter could be a useful guide for estimating femoral component version during total hip arthroplasty. We conducted a study of 88 patients to evaluate the relationship between the posterior lesser trochanter line (PLTL) and the femoral neck axis (FNA) using computed tomographic scans. The mean angle between the PLTL and the FNA was 17.4° ± 7.1° (range, -1.6° to 36.5°). The PLTL angle correlated (r(2) = 0.67-0.72) with the FNA angle. Intraclass correlation coefficient values showed a high level of intraobserver and interobserver agreement in the angles between the PLTL and the FNA. We found a constant relationship between the lesser trochanter and the FNA, and femoral neck version can be estimated, using the PLTL, with reasonable reliability.

Rapidly destructive arthropathy of the hip joint in patients with rheumatoid arthritis.

This article describes 3 patients with rheumatoid arthritis in which hip joint conditions were similar to rapidly destructive arthropathy of the hip joint. The patients had the following additional characteristics: (1) age at diagnosis was comparatively older; (2) rheumatoid arthritis had an onset after age 40 years; (3) severe rheumatoid arthritis was present in >4 major joints; (4) long-term steroids and disease-modifying antirheumatic drugs were taken due to the high activity of rheumatoid arthritis; and (5) patients were underweight, with body mass indexes <20 kg/m(2).Rapidly destructive arthropathy of the hip joint rarely occurs in osteoarthritis, avascular necrosis of the femoral head, and rheumatoid arthritis. Clinically, rapidly destructive arthropathy of the hip joint occurs in elderly patients who report severe pain but have a relatively preserved range of motion. Typical radiologic changes in rapidly destructive arthropathy of the hip joint are rapid destruction, resorption, or subluxation of the femoral head, destruction of the acetabulum, and minimal spur formation developing 6 to 12 months after symptom onset. Destruction of the hip joint in rheumatoid arthritis occurs in the sequence of depression, flattening, and loss, and commonly progresses gradually. When patients with rheumatoid arthritis report persistent and severe pain in the hip joint with no specific cause, rapidly destructive arthropathy of the hip joint must be identified through repetitive follow-up radiographic observations.

Reliability of a PowerPoint method for wear measurement after total hip arthroplasty: a retrieval study using 3-dimensional laser scanning.

The purpose of this study was to evaluate the reliability of the PowerPoint (PP) (2007 Version; Microsoft, Redmond, Wash) method for measuring polyethylene liner wear after total hip arthroplasty. Seventeen retrieved polyethylene liners were included in this study. Wear volumes were calculated using the PP, the Dorr and Wan, and 3-dimensional (3D) laser scanning methods. Spearman correlation coefficients for wear volume results indicated strong correlations between the PP and 3D laser scanning methods (range, 0.89-0.93). On the other hand, Spearman correlation analysis revealed only moderate correlations between the Dorr and Wan and 3D laser scanning methods (range, 0.67-0.77). The PP method can be used to monitor linear wear after total hip arthroplasty and could serve as an alternative method when computerized methods are not available.