The advance of surgical technique and implant design have led to improvement in total hip arthroplasty (THA), and short stem THA is now gaining number as a treatment option for younger patients to preserve bone in the proximal femur for a future revision. The SMF stem is shorter stem, and requires a slightly higher neck resection and implanted in slight varus to contact at lateral cortex. Developmental dysplasia of the hip (DDH) is the most common cause to hip osteoarthritis (OA) in Japan, and the morphology of the dysplastic femur is narrow canal and increased anteversion. Thus, the purpose of this study is to evaluate the SMF stem design can fit for Japanese patients, using CT based 3-D template planning. We evaluated 30 patients who required THA in our institution. Inclusion criteria are hip OA, but cases with post-trauma, post-osteotomy, and any other hip disease in childhood are excluded. Patients were selected with their femoral anteversion, based on the dispersion of anteversion in dysplastic hip population, which was reported by Noble and collegues in 2003. Preoperative planning with ZedHip software (Lexi, Japan) was performed by established protocol. The center of socket was placed at 15mm proximal from teardrop and medialized to primary acetabulum, with 40° of radiographic inclination and 20° of anteversion. Neck resection of femur was 20mm proximal from the top of smaller trochanter, and stem was placed with lateral fit at distal and medial fit at calcar with appropriate size. Stem offset was selected by leg extension and balanced shenton line. Finally, ROM simulation was performed and the socket anteversion was arranged to achieve the optimal ROM. And then, SMF stem alignment and appropriate fitting was evaluated in Japanese OA cases.Introduction
Methods
The purpose of this study was to evaluate periprosthetic bone mineral density (BMD) changes around a cementless short tapered-wedge stem and determine correlations between BMD changes and various clinical factors, including daily activity, after total hip arthroplasty (THA) with a short tapered-wedge stem. The study included 65 patients (65 joints) who underwent THA with a TriLock stem. At baseline, and 6, 12, and 24 months postoperatively, BMDs of the seven Gruen zones were evaluated using dual-energy X-ray absorptiometry. Correlations were determined between BMD changes and clinical factors, including the Harris hip score, body mass index, University of California at Los Angeles (UCLA) activity rating score, age at surgery, and initial lumbar BMD.Purpose
Methods
Failure of acetabular components has been reported to lead to large bone defects, which determine outcome and management after revision total hip arthroplasty (THA). Although Kerboull-type (KT) plate (KYOCERA Medical Corporation, Kyoto, Japan) has been used for compensating large bone loss, few studies have identified the critical risk factors for failure of revision THA using a KT plate. Therefore, the aim of this study is to evaluate the relationship between survival rates for radiological loosening and the results according to bone defect or type of graft. This study included patients underwent revision THA for aseptic loosening using cemented acetabular components with a KT plate between 2000 and 2012. Bone defects were filled with beta Tricalcium phosphate (TCP) granules between 2000 and 2003 and with Hydroxyapatite (HA) block between 2003 and 2009. Since 2009, we have used femoral head balk allografts. Hip function was evaluated by using the Japanese Orthopaedic Association (JOA) score and University of California, Los Angeles (UCLA) activity. Acetabular defects were classified according to the American Academy of Orthopedic Surgeons (AAOS) classification. The postoperative and final follow-up radiographs were compared to assess migration of the implant. Kaplan–Meier method for cumulative probabilities of radiographic failure rate, and the comparison of survivorship curves for various subgroups using the log-rank test were also evaluated. Logistic regression was performed to examine the association of such clinical factors as the age at the time of operation, body mass index, JOA score, UCLA activity score, and AAOS classification with radiographic failure. Odds ratios (ORs) and 95% CIs were calculated. Multivariate analysis was performed to adjust for potential confounders by clinical factors. Values of Introduction
Patients and methods
Implant dislocations are often caused by implant or bone impingement, and less impingement is critical to prevent dislocations. Several reports demonstrated that greater femoral offset delayed bony impingement and led to an improved range of motion (ROM) after THA. Therefore, an increase in the femoral offset may improve ROM and decrease implant dislocation. The aim of this study was to clarify the effect of the femoral offset in avoiding component or bony impingement after total hip arthroplasty (THA). Seventy-eight patients underwent THA with a Pinnacle cup and Summit stem (DePuy). Intraoperative kinematic analysis was performed with a navigation system, which was used to obtain intraoperative range of motion (ROM) measurements during trial insertion of stems of 2 different offset lengths with the same head size. Further, ROM was also measured after actual component insertion.Introduction:
Methods:
The cementless acetabular component fixed with several screws is one of the most widely used approaches in THA. These screws rely on contact pressure and the resultant friction between the screw head and the cup to control translation and angulation of the prosthesis. However, intraoperative change of the acetabular component alignment during screw fixation should be hardly detected. Acetabular component alignment can be assessed using computer-assisted navigation systems with realtime adjustments for component position. The purpose of the current study was to evaluate intraoperative change of acetabular component alignment during screw fixation using navigation system. Primary THAs were performed in 74 hips using CT based fluoroscopic matching navigation system (VectorVision, BrainLAB). The patients were 18 men and 56 women with a mean age of 64.4 years (range, 47–78 years) at operation. Intraoperative acetabular component inclination and anteversion were measured at the time of press-fit, and after screw fixation using the cup verification function in the system. Mean of the absolute difference between at the time of press-fit and after screw fixation was evaluated as intraoperative change of acetabular component. We measured the distance from the center of the femoral head to the inter-teardrop line as a horizontal and vertical reference on the postoperative radiograph. The number of screws was also investigated.Background
Patients and Methods
Total hip arthroplasty for Crowe type IV developmental dysplasia of the hip is a technically demanding procedure. Restoration of the anatomical hip center frequently requires limb lengthening in excess of 4 cm and increases the risk of neurologic traction injury. However, it can be difficult to predict potential leg length change, especially in total hip arthroplasty for Crowe type IV developmental hip dysplasia. The purpose of the present study was to better define features that might aid in the preoperative prediction of leg length change in THAs with subtrochanteric femoral shortening osteotomy for Crowe type IV developmental dysplasia of the hip. Primary total hip arthroplasties with subtrochanteric femoral shortening osteotomy were performed in 70 hips for the treatment of Crowe type IV developmental hip dysplasia. The patients were subdivided into two groups with or without iliofemoral osteoarthritis. Leg length change after surgery was measured radiographically by subtracting the amount of resection of the femur from the amount of distraction of the greater trochanter. Preoperative passive hip motion was retrospectively reviewed from medical records and defined as either higher or lower motion groups.Background
Patients and Methods
