Although the wear of conventional polyethylene liner becomes a serious problem in a long term follow up after total knee arthroplasty, there are few reports of measuring the polyethylene wear. Is it possible to measure the linear wear rates in the non-cross-linked polyethylene liner used in the Press Fit Condylar (PFC) Sigma total knee system? Does the polyethylene wear influence on the clinical results?Background
Questions/purposes
Acetabular bone deficiency, especially proximal and lateral deficiency, is a difficult technical problem during primary total hip arthroplasty (THA) in developmental hip dysplasia (DDH). We report a configuration-based classification of hip, including a definition of shallow acetabulum. We also report a new reconstruction method using a medial reduced cemented socket and additional bulk bone in conjunction with impaction morselized bone grafting (Ad-BBG method). We aimed to evaluate usefulness of the classification and the method's clinical/radiographic outcomes. Forty percent of 330 THAs for DDH were defined as shallow dysplastic hips. The Ad-BBG method was performed on 102 hips (78% of shallow hips). For the 24 remaining hips, THA was performed using the conventional interposition bulk bone grafting (8 hips)or without bone grafting by using rigid lateral osteophyte (16 hips). Operative Technique: Theresected femoral head was sectioned at 1–2-cm thickness, and a suitable size of the bulk bone graft was placed on the lateral iliac cortex and fixed by polylactate absorbable screws. Autogenous impaction morselized bone grafting, with or without hydroxyapatite granules, was performed along with the implantation of medial reduced cemented socket. Radiographic criteria used for determining loosening were migration or a total radiolucent zone between the prosthesis/bone cement and host bone. The follow-up period was 10.2 ± 2.6 (range, 6.0–15.0) years.Introduction
Methods
There is no report of additional type of bulk bone grafting (Ad-BG) method with impaction morselized bone graft for reconstruction of shallow dysplastic hip in total hip arthroplasty. The purpose of this study was to define the shallow acetabulum and to evaluate the clinical and radiographic results of primary total hip arthroplasty (THA) with Ad-BG method. With modification of Crowe's classification, shallow dysplasia was defined and classified BACKGROUND
MATERIALS and METHODS
Although most radiographs used for polyethylene wear measurements have been taken with the patient in the supine position in order to assess penetration by the femoral head into the acetabular polyethylene socket, we have questioned the effect of weight-bearing on the position of the head within the socket. The current study aimed to determine the effect of weight bearing, i.e. standing on the two-dimensional radiographic position of the femoral head within the socket. A total of three hundred and fifty patients (three hundred and eighty three hips) who had had a total hip arthroplasty had digital radiographs made a set of anteroposterior radiographs for each patient: one radiograph was made with the patient supine and one was made with the patient standing in full weight bearing on the replaced hip. The patients were divided into the following two groups: 1) seventy-five patients (eighty-three hips) with conventional polyethylene (CON) (group-1); 2) two hundred and seventy-five patients (three hundred hips) with highly cross-linked polyethylene (XPL) (group-2). The set of radiograph was taken at three weeks postoperatively and at the time of semiannual follow-up. The average ceramic femoral head penetration was measured with radiographs taken in the standing or supine position at the final follow-up and compared with those of three weeks postoperatively. A single researcher with use of a computerized measurement system performed all measurements on the radiographs of the two-dimensional position of the head. Follow-up period were 13.5 ± 1.0 (range. 11.0–15.5) years in group-1 and 7.6 ± 2.1 (range. 5.0–12.6) years in group-2.BACKGROUND:
PATIENTS AND METHODS:
Recently, the use of a large diameter femoral head has been discussed as a means to reduce the risk of hip dislocation after total hip arthroplasty (THA). Although it has been clear that increasing the head size increases the oscillation angle and hip stability, a consensus on the usefulness of a larger head size has not been reached due to an increased propensity for bone impingement. We studied the effect of the range of motion (ROM) and bone impingement caused by increasing the femoral head size using a 3D simulation system. All patients who had undergone a primary THA in our hospital from October 2010 were selected, and we excluded those with severe osteoarthritis, severe dysplasia (Crowe group), or excessive femoral neck anteversion (35°). This resulted in 60 patients (16 men and 44 women), with a mean age of 66.6 years (range, 47–83 years). The diagnoses were osteoarthritis in 42 hips, osteonecrosis in 11 hips, rheumatoid arthritis in four hips, and femoral neck fracture in three hips. A virtual hip model was generated from the preoperative CT scan and a component was virtually implanted via computer simulation software (Zed Hip, LEXI, Japan). The acetabular cup was implanted with an inclination of 45°, anteversion of 20°, and the femoral stem was implanted into the femur recreating the same head height with an anteversion of 25°. We defined three leg positions: (A) maximum flexion (B) internal rotation with hip in 90°of flexion and 20°of adduction as posterior dislocation, and (C) external rotation with hip in 0°of extension as anterior dislocation. In each leg position, range of motion up to the impingement and the type of impingement (implant or bone) was assessed with 22-, 26-, 28-, 32-, and 36 mm femoral head sizes.BACKGROUD/PURPOSE
PATIENTS AND METHODS
Hybrid total hip arthroplasty (THA) commonly recognized as cementless hemi-spherical acetabular component combined with cemented femoral stem. We have done so called “reverse” hybrid THA with cemented socket and cementless stem and compared with all-cemented THAs. We have been collecting data on total hip arthroplasty since November, 1993. Reverse hybrid hip replacements were used mainly from February, 2001. We evaluated data on 272 reverse hybrid THAs (223 patients) from this year onward until May, 2010, and compared the results with those from 283 all-cemented THAs (237 patients) between 1993 and May, 2010. Eighty percent or more of patients had diagnosed as secondary osteoarthritis of the hip joint due to dysplasia in our hospitals. Highly cross linked ultrahigh molecular polyethylene (CLP) socket was introduced in October, 1999. We used conventional (not cross linked polyethylene) socket for 82 hips (cemented group-1) operated before October, 1999 and CLP socket for 201 hips (cemented group-2) in all-cemented cases. We used the Kaplan-Meier method for estimation of prosthesis survival and relative risk of revision. The endpoint was radiological loosening or revision. Socket linear wear rates were also assessed in radiographically. Clinical assessment was performed using the Japanese Orthopedic Association (JOA) scores and Merle d'Aubigne & Postel scores.BACKGROUND
PATIENTS AND METHODS
Acetabular defects are encountered in both primary total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH) and in revision THA. The purpose of this study was to evaluate the clinical and radiographic results of one method of acetabular reconstruction for THA using a hydroxyapatite (HA) block with either an autogenous graft or allograft of impacted morsellized bone in conjunction with a cemented socket. Fourteen hips in 14 patients (all female; average age, 64 years) were treated with the above technique in primary (11 DDH) or revision THA (three loosened sockets). All patients were followed clinically in a prospective fashion, and radiographs were analyzed retrospectively. One initial patient had 16-year follow-up, whereas the remaining 13 patients had follow-up between four and 5.5 years.BACKGROUND
METHODS
The purpose of this study was to examine if Sugioka's transtrochanteric rotational osteotomy (TRO) of the femoral head could be a valid option in treating idiopathic osteonecrosis of the femoral head. Thirty-two TROs performed in 29 patients between 1985 and 2006 were studied. Patient age at operation ranged from 16 to 56 years (average, 36 years). Thirteen hips were in women and 19 hips in men. Height was 165 cm and weight 63 kg (Body Mass Index 23) on average. Risk factors were corticosteroid use in 18 hips and excessive alcohol consumption in 15 hips (2 of them had both backgrounds), while neither of them was found with 1 hip. Bilateral hips were affected in 19 patients and 3 of them underwent bilateral TROs sequentially. The femoral head was rotated anteriorly in 26 hips and posteriorly in 6 hips. For fixation of the osteotomy site, large femoral screws had been used till 1995 (Group 1, 9 hips), and since 1996 an AO angle plate or a compression hip screw has been used (Group 2, 13 hips). Since 2003, pre-operative planning was performed more meticulously and the distal part of the joint capsule was cut after osteotomy as described by Atsumi (Group 3, 10 hips). The average follow-up period was 6.5 years (range, 2 to 21 years).Introduction
Methods
Long term outcome of cementless femoral stem with use of transtrochanteric approach was evaluated by clinical outcome and radiological change. 37 joints in 33 patients who underwent surgery in our department more than 15 years before (from 1986 to 1993) were studied. Used implants were Omnifit (Fit group, 19 joints: all joints were microstructured) and Ominiflex (Flex group, 18 joints: all joints were microstructured). The preoperative diagnosis was secondary osteoarthritis caused by dysplasia of hip (29 joints), osteonecrosis of femoral head (2 joints), rheumatoid arthritis (4 joints), and others (2 joints). Mean age at surgery was 51 years (Fit group, 54.2 years; Flex group, 50.2 years) and average postoperative follow-up period was 17.8 years (Fit group, 19 years; Flex group, 16.5 years). Clinical outcome was evaluated by Japanese Orthopedic Association hip score (JOA score) and absence or presence of thigh pain. In radiological evaluation, the fixation of implant was evaluated by Engh’s classification and the presence or absence of stress shielding, spot welds, radiolucent line, osteolysis, and sinking were studied. JOA score for Fit and Flex group was significantly improved from 35 to 79.3 points and 37 to 76.9 points, respectively. Improvement of pain and gait ability was marked. Thigh pain was observed in 1 joint only, in the Flex group. Radiological examination for Fit and Flex group showed bone ingrowth 100% and 61% of patients, respectively, showing good fixation for both groups. Radiological sign of Fit and Flex group showed stress shielding in 91% and 84%, spot welds in 73% and 44%, radiolucent line in 12% and 19%, osteolysis in 5.2% and 5%, and sinking in 0% and 11% of patients, respectively. Revision caused by loosening of stem was in only 1 joint in Flex group. For first generation of Omnifit/Omniflex stem, many cases of early loosening caused by surface structure characteristics had been reported. Long-term outcome in our department was relatively good compared to these earlier reports. Good initial placement of femoral component and sufficient canal fill ratio with use of transtrochanteric approach is one factor of this better result.
A seventy-one-years old, female, has been treated by hemodialysis from 1977 due to renal failure. In April 19, 1985, she had Charnley Low Friction Arthroplasty for right hip joint. She often felt mild pain on the joint from 2000. Radiograph showed central migration of the socket and huge cystic bone defect of the acetabulum surrounded by thin cortical bone like an egg-shell form. Tear drop (acetabular floor) was diminished due to massive bone destruction or severe osteolysis. CT showed that the diameter of the cavity was approximately 10 cm. In March 1, 2002, the socket was upside down and moving freely in the cavity. The patient could not weight-bear on right lower extremity but walk without two crutches. Hemiarthroplasty for her left hip joint (contra-lateral side) was done in June 26, 2006, due to femoral neck fracture. Because of continuous right hip joint pain and walking disturbance, she underwent revision surgery in May 20, 2008. At the surgery, the cavity was empty except for the socket and fibrous tissue. Impaction grafting by using morselized allograft including porous and solid hydroxyapatite granules (100 g and 40 g each) was done after the socket and the tissue were extracted. A custom made all polyethylene socket (73 × 68 mm in diameter) was fixed by polymethylmetacrylate bone cement. Postoperative course was uneventful. She can walk with one crutch and ride on/off a vehicles without help four months postoperatively. It is often difficult to reconstruct acetabulum with large bone defect in revision total hip arthroplasty. Especially, almost of support rings with hook cannot be applied in the case that the tear drop is destructive or absorbed. Impaction bone grafting is commonly used for reconstruction of bone defect in revision surgery. However, the extremely thick graft for large bone defect is at risk of collapsing lead to implant migration. The socket used in the case was custom made jumbo type to reduce the thickness of impaction grafting. It seems to be one of resolution to use the custom made jumbo socket for the case with large defect of acetabulum in revision total hip Arthroplasty.
