Intraoperative blood pressure changes during cemented versus uncemented bipolar hemiarthroplasty for displaced femoral neck fracture: a multi-center cohort study : The effect of bone cement for bipolar hemiarthroplasty in elderly patients.

INTRODUCTION: The purpose of this study was to compare the cemented bipolar hemiarthroplasty with uncemented about the change of intraoperative blood pressure and the incidence of major complications in elderly patients with femoral neck fracture. MATERIALS AND METHODS: This multiple center prospective cohort study included only patients with acute displaced femoral neck fracture (Garden stage III or IV). All patients were treated with cemented or uncemented bipolar hemiarthroplasty using modified Hardinge or Watson-Jones approach in the lateral decubitus position. Baseline data, medical history, type of anesthesia, FiO2 value, the number of vasopressor using during operation, femoral component, intraoperative blood pressure, SaO2, and major complications were evaluated. RESULTS: Of 164 patients (45 males and 119 females), 86 underwent cemented and 78 underwent uncemented bipolar hemiarthroplasty. Baseline medical histories were similar in both groups. In both the cemented and uncemented groups, intraoperative systolic blood pressure significantly decreased during cementing or rasping (106.3 and 103.6 mmHg) and after femoral component insertion (103.3 and 99.1 mmHg) compared to before rasping (120.7 and 116.4 mmHg) (p < 0.0001, respectively). Donaldson's grade seemed more favorable in uncemented group than in cemented group during cementing or rasping, during stem insertion; however, no patients experienced the lethal complication in both groups. CONCLUSIONS: Intraoperative blood pressure did not change during cemented and uncemented bipolar hemiarthrplasty for displaced femoral neck fracture. If the standard modern cement technique was performed during operation, bone cement is a safe and acceptable for elderly patients who have a lot of medical histories.

The incidence of alcohol-associated osteonecrosis of the knee is lower than the incidence of steroid-associated osteonecrosis of the knee: an MRI study.

OBJECTIVE: The purpose of the study was to clarify the incidence of alcohol-associated osteonecrosis of the knee using MRI. METHODS: A total of 131 patients (56 women and 75 men) with osteonecrosis of the femoral head were enrolled; 60 patients had a history of alcohol abuse and 71 had previously received steroids. All patients underwent MRI of the knee. The incidence of alcohol-associated osteonecrosis of the knee was compared with that of steroid-associated osteonecrosis of the knee. Predictive factors of alcohol- and steroid-associated osteonecrosis of the knee were also evaluated. RESULTS: The incidence of alcohol-associated osteonecrosis of the knee was lower than that of steroid-associated osteonecrosis of the knee (18.3 vs 54.9%; P < 0.001, Fisher's exact probability test). No significant difference in weekly alcohol consumption was observed between patients with osteonecrosis of the knee and those without osteonecrosis of the knee. No significant difference in daily maximum steroid doses was observed between patients with osteonecrosis of the knee and those without osteonecrosis of the knee. CONCLUSION: The present study revealed that the incidence of alcohol-associated osteonecrosis of the knee is lower than that of steroid-associated osteonecrosis of the knee.

A pilot project for the Japan arthroplasty register.

BACKGROUND: National arthroplasty registers are valuable tools for reporting on an updated epidemiologic survey of arthroplasties and for evaluating the performance of implants and operative procedures through the early identification of failure risk factors. More than ten registers have been launched globally, but no national register has been reported in Asia. METHODS: In February 2006, a pilot project of the Japan Arthroplasty Register (JAR) for total hip arthroplasty (THA) and total knee arthroplasty/unicompartmental knee arthroplasty (TKA/UKA) was launched by the Japanese Orthopaedic Association (JOA). Data obtained include information about patients, primary and revision arthroplasty operative procedures, and implants and materials used. The JAR office accumulated and processed all data and reports annually. RESULTS: Up to May 2011, 83 of 130 hospitals nominated by the JOA (64 %) participated in the JAR pilot project. From 2006 to 2011, 33,080 data collection forms were submitted; 17,534 for THA and 17,269 for TKA/UKA. A brief summary of the annual report of the JAR is available from The Japanese Society for Replacement Arthroplasty web site at http://jsra.info/ . CONCLUSION: A national arthroplasty register is a useful tool for evaluating the outcomes of interventions and the materials used in arthroplasties and for providing rapid feedback to practitioners and patients about any failure of THA and TKA/UKA. As the first national arthroplasty register in Asia, the JAR will help guide the development of registers of arthroplasty characteristics specific to Asian populations.

Incidence of osteonecrosis associated with corticosteroid therapy among different underlying diseases: prospective MRI study.

OBJECTIVES: The purpose of this study was to clarify the incidence of (CS)-associated osteonecrosis among different underlying diseases and to evaluate the risk factors for steroid-associated osteonecrosis in a prospective MRI study. METHODS: We prospectively used MRI to study 337 eligible underlying disease patients requiring CS therapy and succeeded in examining 1199 joints (hips and knees) in 302 patients with MRI for at least 1 year starting immediately after the onset of CS therapy (1-year follow-up rate of 90%). The underlying diseases included SLE in 687 joints (173 patients) and a variety of other rheumatological disorders in 512 joints (129 patients). RESULTS: The incidence of osteonecrosis was significantly higher in SLE patients than in non-SLE patients (37 vs 21%, P = 0.001). Logistic regression analysis revealed that adolescent and adult patients had a significantly higher risk of osteonecrosis compared with paediatric patients [odds ratio (OR) = 13.2], that high daily CS dosage (>40 mg/day) entailed a significantly higher risk of osteonecrosis compared with the dosage of <40 mg/day (OR = 4.2), that SLE patients had a significantly higher risk of osteonecrosis compared with non-SLE patients (OR = 2.6) and that male patients had a significantly higher risk of osteonecrosis compared with female patients (OR = 1.6). CONCLUSION: These findings suggest that the incidence of CS-associated osteonecrosis varies among different underlying diseases.

Quantitative T2 mapping of femoral head cartilage in systemic lupus erythematosus patients with noncollapsed osteonecrosis of the femoral head associated with corticosteroid therapy.

PURPOSE: To evaluate articular cartilage degeneration with transverse relaxation time (T2) mapping in systemic lupus erythematosus (SLE) patients with noncollapsed and asymptomatic osteonecrosis of the femoral head associated with corticosteroids. MATERIALS AND METHODS: T2 mapping with a 1.5-T magnetic resonance imaging system was prospectively performed for 28 normal hips from 14 healthy volunteers (control group) and 15 hips from 10 SLE patients that met the inclusion criteria of noncollapsed and asymptomatic osteonecrosis of the femoral head (osteonecrosis group). Exclusion criteria were past experience of pain, trauma, infection, or prior hip joint surgery. Distribution of T2 values of the femoral head cartilage were compared between the control group and the osteonecrosis group with respect to acetabular dysplasia by center-edge angle (CEA). RESULTS: T2 values of the femoral head cartilage were significantly higher in the osteonecrosis group than in the control group (34.4 msec vs. 30.8 msec, P = 0.001). Multiple regression analysis revealed that the osteonecrosis group and decreased CEA was significantly associated with high T2 values (T2 value = 34.6 + 3.6 × [osteonecrosis] - 0.14 × CEA, R(2) = 0.52, P = 0.003). CONCLUSION: Degeneration of articular cartilage was associated with osteonecrosis of the femoral head in SLE patients and acetabular dysplasia.

Dorsal root ganglion neurons with dichotomizing axons projecting to the hip joint and the knee skin in rats: possible mechanism of referred knee pain in hip joint disease.

BACKGROUND: Patients who have hip joint diseases sometimes complain of knee pain as well as hip joint area pain. However, the precise sensory innervation pattern and correlation of the sensory nerves of the hip joint and knee are unknown. The purpose of this study was to investigate dorsal root ganglion (DRG) neurons with dichotomizing axons projecting to both the hip joint and the knee skin in rats using double fluorescent labeling techniques, and to examine characteristics of the DRG neurons with dichotomizing axons using immunohistochemical staining for inflammatory neuropeptides such as calcitonin gene-related peptide (CGRP). METHODS: For 20 rats, two kinds of neurotracers, Fluoro-Gold (FG) and 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate (DiI), were used in the double-labeling study. FG was injected into the left hip joint, and DiI was applied to the left medial portion of knee skin. Ten days after application, bilateral DRGs were harvested and immunohistochemically stained for CGRP. RESULTS: DRG neurons double labeled with FG and DiI were observed only from L2 to L4 on the left side. Approximately 1.6% of all DRG neurons innervating the hip joints had other axons that extended to the medial portion of knee skin, and 35% of double-labeled neurons were CGRP positive. CONCLUSIONS: Our results showed that the double-labeled neurons had peripheral axons that dichotomized into both the hip joint and the knee skin. CGRP-positive neurons of these dichotomizing fibers may play some role in the manifestation of referred knee pain with hip joint pain.

Inter-observer and intra-observer reliabilities of the Japanese Ministry of Health, Labor and Welfare type classification system for osteonecrosis of the femoral head.

The aim of this study was to clarify the reproducibility of the Japanese Ministry of Health, Labor and Welfare (JMHLW) type classification for osteonecrosis of the femoral head. We performed inter-observer and intra-observer trials using 40 sets of magnetic resonance imagings, 20 of which were produced by a 0.5 Tesla (T) superconductive unit and the other 20 produced by a 1.5 T unit, in patients with non-collapsed and asymptomatic osteonecrosis of the femoral head (JMHLW stage 1 or 2). The JMHLW type classification (A, B, C1, or C2) was determined from T1-weighted coronal images at the center of the femoral head. Six orthopedic surgeons independently assessed all 40 images twice, with an interval of 4-5 weeks between sessions. Regarding inter-observer reliability, the percent agreement was 85% and weighted kappa was 0.709 for 0.5 T, versus a percent agreement of 82% and weighted kappa of 0.724 for 1.5 T. Regarding intra-observer reliability, the percent agreement was 82% and weighted kappa was 0.780 for 0.5 T versus a percent agreement of 80% and weighted kappa of 0.800 for 1.5 T. Inter-observer and intra-observer reliabilities did not differ significantly between the 0.5 and 1.5 T units. The JMHLW type classification provided high inter-observer and intra-observer reliabilities.

The pattern of distribution of PGP 9.5 and TNF-alpha immunoreactive sensory nerve fibers in the labrum and synovium of the human hip joint.

To date, there has been no report clarifying the existence of sensory nerve fibers as the origin of the hip joint pain of osteoarthritis. We examined the existence of sensory nerve fibers in osteoarthritis (OA), osteonecrosis of the femoral head (ONFH), and femoral neck fracture of the human hip joint. Ten labra of 10 human hip joints were harvested during a total hip arthroplasty. Each labrum was separated into 12 sections and we used three sections for analysis, which included 2 weight-bearing and 1 non-weight-bearing portion. Protein gene product 9.5 (PGP 9.5) immunoreactive sensory nerve fibers were found in the labrum and synovium harvested from the weight-bearing portion in the OA group. Some of these sensory nerve fibers were also positive for tumour necrosis factor alpha (TNF). The PGP 9.5 immunoreactive sensory nerve fibers existed in the labrum tissue and inflammatory TNF positive cells were observed in the hyperplastic synovium. On the other hand, we could not demonstrate PGP 9.5 or TNF immunoreactive sensory nerve fibers and cells in any of the ONFH group or the non-weight-bearing portion in the OA group. These data suggest that the pain of ONFH and OA of the hip joint have different pathogenetic mechanisms and that the invasion of sensory nerve fibers containing TNF may be involved in the pathogenesis of pain in the human hip joint affected by OA.

Differences in innervation and innervated neurons between hip and inguinal skin.

Pain originating from the hip may be referred to the groin and anterior thigh. We investigated sensory dorsal root ganglion neurons innervating the hip and the inguinal skin in rats using retrograde neurotransport and immunohistochemistry. A retrograde neurotracer Fluoro-Gold was injected into the left hip or inguinal skin of rats. Seven days later, we harvested bilateral dorsal root ganglions and counted the number of Fluoro-Gold-labeled neurons positive for calcitonin gene-related peptide, a marker of nerve growth factor-dependent neurons, or isolectin B4, a marker of glial cell line-derived neurotrophic factor-dependent neurons. In the hip group, Fluoro-Gold-labeled neurons were distributed throughout the left dorsal root ganglions from T13 to L5, primarily at L1, L2, L3, and L4, and the percentage of calcitonin gene-related peptide-positive neurons was higher than that of isolectin B4-binding neurons. In the inguinal skin group, Fluoro-Gold-labeled neurons were distributed throughout the left dorsal root ganglions from T13 to L3, primarily at L1, L2, and L3, and the percentage of isolectin B4-binding neurons was higher than that of calcitonin gene-related peptide-positive neurons. These data suggest the sensory innervation pattern and characteristics of the sensory nerve of the rat hip are different from those of inguinal skin.

Hip arthrography under general anesthesia to refine the definition of hinge abduction in Legg-Calvé-Perthes disease.

BACKGROUND: Hinge abduction is widely accepted as a poor prognostic factor in Legg-Calvé-Perthes disease (LCPD), whereas the exact definition of hinge abduction remains ill defined. The purpose of this diagnostic study was to refine the definition of hinge abduction in LCPD using conventional hip arthrography under general anesthesia. METHODS: Among 350 hips in 332 LCPD patients, we reviewed 92 hips in 90 patients (75 boys and 15 girls) who consecutively underwent arthrography under general anesthesia because of an expected poor prognosis. The mean age at LCPD onset was 8.2 years (range, 4-13 years). With respect to lateral pillar classification, 25 hips were classified as group B, 27 as B/C border, and 40 as C. Subluxation (>or=3-mm difference from unaffected side) was present in 81 (88%) of the 92 hips. The modified Waldenström classification was used for evaluating the radiographic stage of disease at the time of arthrography: 80 hips were classified as fragmentation stage and 12 as reossification stage. Hinge abduction was defined as an increased subluxation index in maximum abduction and/or a positive impingement sign. RESULTS: Under this definition, 11% (10 hips) of the study group had hinge abduction. The range of abduction under general anesthesia (40 degrees) was significantly greater than in the awake condition (24 degrees, P < 0.0001). CONCLUSIONS: The subluxation index and the impingement sign proved to be reliable indicators for diagnosing hinge abduction. Conventional arthrography remains useful. General anesthesia provided an analgesic effect and muscle relaxation. LEVEL OF EVIDENCE: Level II (diagnostic study, development of diagnostic criteria on the basis of consecutive patients).

The influence of bone cement and American Society of Anesthesiologists (ASA) class on cardiovascular status during bipolar hemiarthroplasty for displaced femoral-neck fracture: A multicenter, prospective, case-control study.

BACKGROUND: Little is known about how bone cement and American Society of Anesthesiologists (ASA) classification influence the cardiovascular system in elderly patients with femoral-neck fractures treated with cemented hemiarthroplasty. Therefore, we performed a case-control study to investigate these questions and compared the following:≥ASA III with≤ASA II patients who underwent cemented hemiarthroplasty; and cemented with cementless hemiarthroplasty in≥ASA III patients. HYPOTHESIS: ASA classification influences the cardiovascular system during cemented hemiarthroplasty and bone cement influences intraoperative blood pressure [IBP] in patients rated≥ASA III. MATERIALS AND METHODS: This multicenter, prospective study included patients with acute displaced femoral-neck fractures. Baseline data, medical history, anesthesia, FiO2, vasopressor use, femoral component, IBP, SpO2, and complications were evaluated. Of 200 patients, 100 were cemented (mean age, 77±10 years), and 100 were cementless (mean age, 78±9 years). Cemented hemiarthroplasty employed a third-generation technique (plugging, irrigating, drying and filling the canal with cement under pressurization). RESULTS: Systolic blood pressure (SBP) decreased significantly during cementing, versus pre-rasping in≤ASA II patients (from 117.9±24.5 [range, 65-199] to 106.9±20.3 [range, 59-172]; p=0.007), in≥ASA III patients (from 129.5±21.0 [range, 90-169] to 110.4±17.9 [range, 79-157]; p=0.006), and post-stem-insertion, versus pre-rasping in≤ASA II patients (from 117.9±24.5 [range, 65-199] to 103.9±20.7 [range, 53-178]; p=0.0004), and in≥ASA III patients (from 129.5±21.0 [range, 90-169] to 111.2±24.6 [range, 70-156]; p=0.009). In≥ASA III patients, SBP decreased significantly during cementing or rasping, versus pre-rasping in cemented patients (from 129.5±21.0 [range, 90-169] to 110.4±17.9 [range, 79-157]; p=0.006), in cementless patients (from 115.0±17.7 [range, 85-150] to 100.7±15.7 [range, 75-142]; p=0.004), and post-stem-insertion, versus pre-rasping in cemented patients (from 129.5±21.0 [range, 90-169] to 111.2±SD [range]; p=0.009), and in cementless patients (from 115.0±17.7 [range, 85-150] to 89.4±17.5 [range, 58-140]; p<0.0001). There were no lethal complications. CONCLUSIONS: This study indicate a similar hemodynamic change intraoperatively between≤ASA II patients and≥ASA III patients in the cemented group, and between patients with cemented and cementless hemiarthroplasty in the≥ASA III patients. With modern hemiarthroplasty techniques, bone cement might be as safe as cementless techniques in elderly,≥ASA III patients. LEVEL OF EVIDENCE: III, multicenter case-control cohort study.

Expression of the Nd1 gene is down-regulated by doxorubicin at post-transcriptional level.

Doxorubicin is an anti-neoplastic agent with cardiotoxicity as a side effect. We previously demonstrated that doxorubicin treatment of mice resulted in a selective decrease in expression of the Nd1 gene, which encoded a new kelch family actin binding protein in the heart. Here we show that doxorubicin treatment also reduced the Nd1 expression in various organs of mice and cultured cell lines. The treatment of Nd1-transgenic mice and Nd1-transfectants also selectively reduced levels of the exogenous Nd1 mRNAs, whose expression was under the control of various promoters. Furthermore, the doxorubicin-induced reduction of Nd1 mRNA expression in NIH3T3 cells was inhibited by treatment of these cells with cycloheximide. Thus, the doxorubicin treatment may specifically reduce the stability of Nd1 mRNA.

[Acetabular osteotomy for osteoarthritis of the hip joint due to congenital dysplasia].

There are several reports of the treatment for osteoarthritis due to congenital dysplasia of the hip joint. Rotational acetabular osteotomy, Chiari osteotomy and shelf operation has been introduced as the representative acetabular osteotomy. In this paper, we presented our indication of these procedures for dysplastic hip and showed indicative cases.

Anatomically designed prosthesis without cement for the treatment of osteoarthritis due to developmental dysplasia of the hip: 6- to 13-year follow-up study.

BACKGROUND: Morphological differences of dysplastic hips exist not only on the acetabular side but also on the femoral side. Therefore, for reconstructing the hip joint of these patients, the shape of the proximal femur is problematic for getting adequate "fit and fill" by cementless stems. The purpose of this study was to investigate the clinical and radiological outcomes of anatomically designed prostheses for the treatment of osteoarthritis due to developmental dysplasia of the hip. METHODS: A total of 81 consecutive primary cementless total hip arthroplasties using an anatomic hip system were performed in 75 patients (10 men, 65 women). The mean age at the time of the surgery was 59.0 years (range 41-84 years). The average duration of follow-up was 101.4 months (range 72-157 months). Clinical performance was evaluated using the Harris hip score (HHS), and radiographic findings were assessed using the fixation and stability score according to Engh et al. RESULTS: The average preoperative HHS was 44.5 points, and the most recent average HHS was 87.5 points. Altogether, 66 hips (81%) were deemed excellent (>or=90 points) or good (80-89 points). The mean fixation and stability score was 19.6 +/- 5.2 points. In total, 75 (93%) of the femoral components had bone-ingrown fixation, and 6 (7%) indicated possible ingrowth. There was osteolysis around five femoral components and three acetabular components. No femoral component was revised; however, five cups were revised because of breakage of the polyethylene or massive osteolysis. Dislocation of the hip implant was seen in one hip, but there was no recurrent dislocation. There was no deep infection, deep vein thrombosis, or nerve palsy. CONCLUSIONS: The anatomic stem showed acceptable clinical and radiological results in cases with mild or moderate subluxation of the hip at the intermediate-term follow-up.

Utility of four-dimensional analysis of the acetabular labrum applying motion-gated multislice computed tomography: comparison with arthroscopy and harris hip score.

To analyze the kinesis and morphology of the acetabular labrum (AL) noninvasively, we applied 4-dimensional arthrography with motion-gated multislice computed tomography and compared the results with arthroscopy and Harris hip score (HHS) in 49 symptomatic patients who performed reciprocating hip flexion-extension as we carried out mimic retrospective electrocardiogram-gating acquisition. The kinematics and morphology of AL were classified as stabilized, irregular, or eccentric motion patterns. Of the 9 subjects who had intact or frayed AL on arthroscopy, 7 had stabilized motion (average 50 HHS) and 2 had irregular (44 HHS) motion by CT arthroscopy. Of the 16 without adhesive AL on arthroscopy, 6 had irregular motion (48 HHS) and 4 had eccentric motion (58 HHS). We found that the 4-dimensional arthrography with motion-gated multislice computed tomography can reveal both kinetic and morphological changes of the AL, and facilitate further stratification in subjects with the American Academy of Orthopaedic Surgeons class 0, or 1 or without "detached" morphological findings by arthroscopy.

Repair of cartilage defects and torn acetabular labrum in hip joints after conventional osteotomy: evaluation by follow-up arthroscopy.

The purpose of this study was to evaluate recovery from cartilage damage and labral lesions after osteotomy of hip joints. Conventional osteotomy for dysplastic hips was performed on 38 hips. Hip arthroscopy preceded the osteotomy, which in turn was followed up 18.9 months later on average by arthroscopy. We assessed the Harris hip score (HHS) and radiological and arthroscopic findings before and after osteotomy. The average HHS was improved from 64.9 to 88.5. Cartilage repair was observed on the acetabular side of five hips (13.2%) and on the femoral side of four (10.5%). At follow-up arthroscopy, the acetabular labrum had adhered to the capsule in 11 hips. Acetabular adhesion may increase stability of the joint. We conclude that the effects of conventional osteotomy are limited, and additional surgery might be needed in the future.

Automatic measurement of polyethylene modification in metal-backed artificial hip joints using three-dimensional CT.

A new method has been developed for automatic measurement of polyethylene linear modification using three-dimensional CT in total hip arthroplasty (THA) and bipolar hemiarthroplasty (BHP). We obtained a three-dimensional digital image of the metal components by widening the maximum window width, adjusting the proper cutoff threshold level, and removing the metal artifact. The centric coordinates of both the metal-backed cup and the femoral head were calculated from this image. Modification was defined as a change in distance between those two points from their original interval. Phantom studies of the accuracy and reproducibility of the method indicated that the average error ranged from 0.02 to 0.12 mm and the standard deviation ranged from 0.01 to 0.05 mm. Clinical in vivo measurement was performed without error of computer software on 19 hips in which modification of highly cross-linked polyethylene components was significantly large.

Oxidation-induced dynamic changes in morphology reflected on freeze-fractured surface of gamma-irradiated ultra-high molecular weight polyethylene components.

Oxidative degradation of ultra-high molecular weight polyethylene (UHMWPE) attributed to sterilization by gamma-radiation in the presence of air has been cited as one of the major causes of premature wear in total joint arthroplasty. For example, in retrieved UHMWPE tibial bearings, not only adhesive and abrasive wear, but also fatigue wear characterized by delamination and fracture is frequently observed. In this study, we examined the effects of gamma radiation on the microstructural morphology of UHMWPE tibial bearings, and propose a severe fatigue wear mechanism. Scanning electron microscopic observations were conducted on freeze-fractured surface of retrieved UHMWPE components that had been sterilized with gamma radiation in air before implantation, unused components that had been stored on the shelf for several years (5-11) after sterilization, and disc specimens given an accelerated aging protocol after gamma radiation. Scanning electron microscopic observations showed that the freeze-fractured surface of these components had a double layer, which was bordered below the surface. A closer observation of the subsurface layer below the border revealed an extremely rough and porous honeycomb-like structure. Fourier transform infrared analysis demonstrated that the honeycomb-like region in the subsurface had a high oxidation level. The internal morphology of oxidized UHMWPE was classified into four categories based on the level of the oxidation. According to these results, the morphological changes with oxidative degradation of gamma-irradiated UHMWPEs in the presence of air could consistently be explained as the result of major chemical and physical changes such as increased crystallinity, elevated density, and reduced mechanical strength. We relate the morphological changes caused by oxidative degradation in the subsurface to the location of the origin of fatigue wear in total knee joints.

Three-dimensional shape of the dysplastic femur: implications for THR.

This study evaluates the three-dimensional anatomy of the femur with congenital dysplasia of the hip (CDH) in comparison with healthy controls. Computed tomographic scans were obtained from 207 women (154 with dysplasia; 54 healthy controls) with an average age of 51.6 years (range, 18-82 years). Most of the dysplastic joints were classified as Crowe I (43%), or Crowe II or III (48%), with 9% Crowe IV. Individualized three-dimensional computer models of the femur were generated by reconstruction of the CT scans. Dimensional and morphometric parameters were derived by computer analysis of each of the femoral reconstructions. The dysplastic femurs had shorter necks and smaller, straighter canals than the controls. The shape of the canal became more abnormal with increasing subluxation. Detailed analysis showed that the primary deformity of the dysplastic femur is rotational, with an increase in anteversion of 5 degrees to 16 degrees, depending on the degree of subluxation of the hip. The rotational deformity of the dysplastic femur arises within the diaphysis between the lesser trochanter and the isthmus and is not attributable to a torsional deformity of the metaphysis. This study shows that there is a significant difference in the geometry of the normal femurs and those with CDH, even in mild cases. In CDH cases, we recommend the use of modular or specially-designed components to accommodate the shape of the dysplastic canal.