The long-term results of grafting with hydroxyapatite granules for acetabular deficiency in revision total hip replacement are not well known. We have evaluated the results of revision using a modular cup with hydroxyapatite grafting for Paprosky type 2 and 3 acetabular defects at a minimum of ten years’ follow-up. We retrospectively reviewed 49 acetabular revisions at a mean of 135 months (120 to 178). There was one type 2B, ten 2C, 28 3A and ten 3B hips. With loosening as the endpoint, the survival rate was 74.2% (95% confidence interval 58.3 to 90.1). Radiologically, four of the type 3A hips (14%) and six of the type 3B hips (60%) showed aseptic loosening with collapse of the hydroxyapatite layer, whereas no loosening occurred in type 2 hips. There was consolidation of the hydroxyapatite layer in 33 hips (66%). Loosening was detected in nine of 29 hips (31%) without cement and in one of 20 hips (5%) with cement (p = 0.03, Fisher’s exact probability test). The linear wear and annual wear rate did not correlate with loosening.

These results suggest that the long-term results of hydroxyapatite grafting with cement for type 2 and 3A hips are encouraging.

Lumbar spondylolysis is a stress fracture of the pars interarticularis. We have evaluated the site of origin of the fracture clinically and biomechanically.

Ten adolescents with incomplete stress fractures of the pars (four bilateral) were included in our study. There were seven boys and three girls aged between 11 and 17 years. The site of the fracture was confirmed by axial and sagittal reconstructed CT. The maximum principal tensile stresses and their locations in the L5 pars during lumbar movement were calculated using a three-dimensional finite-element model of the L3-S1 segment.

In all ten patients the fracture line was seen only at the caudal-ventral aspect of the pars and did not spread completely to the craniodorsal aspect. According to the finite-element analysis, the higher stresses were found at the caudal-ventral aspect in all loading modes. In extension, the stress was twofold higher in the ventral than in the dorsal aspect.

Our radiological and biomechanical results were in agreement with our clinical observations.

We compared a modular neck system with a non-modular system in a cementless anatomical total hip replacement (THR). Each group consisted of 74 hips with developmental hip dysplasia. Both groups had the same cementless acetabular component and the same articulation, which consisted of a conventional polyethylene liner and a 28 mm alumina head. The mean follow-up was 14.5 years (13 to 15), at which point there were significant differences in the mean total Harris hip score (modular/non-modular: 98.6 (64 to 100)/93.8 (68 to 100)), the mean range of abduction (32° (15° to 40°)/28 (0° to 40°)), use of a 10° elevated liner (31%/100%), the incidence of osteolysis (27%/79.7%) and the incidence of equal leg lengths (≥ 6 mm, 92%/61%). There was no disassociation or fracture of the modular neck.

The modular system reduces the need for an elevated liner, thereby reducing the incidence of osteolysis. It gives a better range of movement and allows the surgeon to make an accurate adjustment of leg length.

Ceramic heads and highly cross-linked polyethylene (HXLPE) as bearing surface materials have been introduced to reduce the production of polyethylene wear particles. The present study hypothesized that the wear rate of HXLPE could be further reduced when combined with a ceramic head. The purpose of this study was to compare the in vivo wear of Longevity HXLPE against cobalt-chromium and zirconia heads after a minimum 5-year follow-up.

A prospective cohort study was performed in 102 cementless total hip arthroplasties (THAs) with the Longevity HXLPE socket (Zimmer) between June 2000 and October 2001. Same prostheses were used in all cases both acetabular cups (Trilogy; Zimmer) and femoral stems (Versys Fiber Metal Taper; Zimmer). 26-mm zirconia heads (NGK) or 26-mm cobalt-chromium heads (Zimmer) were randomly used in 51 hips each. A minimum 5-year follow-up was completed for 47 hips with zirconia heads and 46 hips with cobalt-chromium heads. Two-dimensional linear wear of Longevity HXLPE was measured using computer-assisted methods (PolyWare) on annual x-rays, and total head penetration rates and steady state wear rates were calculated. In addition, periprosthetic osteolysis was evaluated.

At a mean 6-year follow-up, the total head penetration rates were 0.034±0.016 mm/year (zirconia) and 0.031±0.015 mm/year (cobalt-chromium). The steady state wear rates were −0.01 mm/year (zirconia) and −0.01 mm/year (cobalt-chromium). No significant difference was seen between the two groups (p=0.4 and p=0.91). Osteolysis was not observed around prostheses in any hips.

In conclusion, no advantage was seen for the zirconia head compared with the cobalt-chromium head in this time period.

To analyze the long term results of a third generation ceramic on ceramic bearing in cementless total hip arthroplasty (THA), we reviewed the clinical and radiological results of 100 consecutive THAs performed in 86 patients (68 females, 80 hips; 18 males, 20 hips) between 1996 and 1998. The average age at operation was 55 years with a range of 26 to 73 years. The diagnoses were osteoarthritis in 83 hips, osteonecrosis in 10 hips and rheumatoid arthritis in 7 hips. The articulation was composed of a hemispherical titanium porous bead-coated cup (AnCA), a Biolox Forte alumina ceramic cup liner and a ball with a diameter of 28-mm. The modular ceramic liner was fixed directly to the metal cup without polyethylene sandwich or metal rim. A press-fit technique of 1 mm under-reaming without screws was used for cup fixation. The ceramic head was fixed to a 12/14 taper cone of a modular neck which allowed changes in neck-shaft angle, anteversion, and offset. All operations were performed via a posterolateral approach under general anesthesia. To measure the cup orientation, an ellipse was fitted to the acetabular component rim on the early postoperative AP radiographs using computer software. The average cup inclination and anteversion in the radiographic definition were 41 (range 28 to 63) and 17 (range 3 to 34) degrees, respectively. 22 cups were outside the Lewinnek safe zone. All patients were radiographically evaluated in term of implant stability at two years using Engh’s criteria. All of the acetabular components radiologically were judged to be bone-ingrown stable at two years except one cup. 98 stems were judged to be bone-ingrown stable and the remaining two stems were judged to be fibrous stable at two years. After two years, all patients except for two were followed up clinically and radiologically for at least 10 years or until revision or death. One unstable cup was revised at 2.5 years. This case had a previous Chiari’s pelvic osteotomy and insufficient press-fit of the cup was assumed to have led to loosening. One of the two fibrous stable stems was revised at six years due to aseptic loosening. One rheumatoid arthritis hip with stable bone ingrown fixation developed late infection at six years and was revised. One stable cup showed chipping of the acetabular liner at 8 years and required revision. The orientation of this cup was 55 degrees of inclination and 17 degrees of anteversion and the high inclination was thought to be related to the ceramic liner chipping. The remaining hips showed no osteolysis or loosening at the final follow-up. There were no squeaking hips. The 10-year survivorships with the endpoint of mechanical loosening or revision were 96.7% and 95.6%, respectively. We conclude that the third generation ceramic on ceramic hip bearing without polyethylene sandwich provided long term stability and eliminated periprosthetic osteolysis.

The anterior pelvic plane (APP) through the bilateral anterior superior iliac spines (ASIS) and pubic tuberosities is often used as a pelvic reference in measuring orientation of the acetabular cup in total hip arthroplasty. Apophyses such as ASIS are, however, anatomically variable among patients and APP does not always represent the functional pelvic tilt in the sagittal plane in each patient. Therefore, malposition of the cup and recurrent dislocation may occur even though the cup is placed in a safe zone when measured against APP. We analyzed dynamic pelvic tilt angle in the sagittal plane using a motion analysis system after THA and we found a case of recurrent dislocation due to an unusual APP tilt.

A 77-year-old woman underwent primary THA 3 years ago and cup re-implantation was done with the use of a 10-degree elevated liner and the head diameter was increased from 26mm to 28 mm after two anterior dislocations. However, posterior dislocation occurred 11 times after this. A second revision was performed with a 36 mm head and cup anteversion was optimized against APP. Further posterior dislocations occurred twice again. To probe the cause of recurrent dislocation, we performed motion analysis using a 6-camera VICON system and the markers were registered to the bone and implant models based on the postoperative CT images. This system visually represents four-dimensional dynamic motions that include the time sequential transitions of components and their posture. The cup had been placed in 6 degrees of radiographic anteversion against APP, and in −13 degrees of radiographic retroversion in supine (FPP), because the pelvic flexion angle in supine was 17.6 degrees. Furthermore, when standing, the pelvic flexion angle increased 10 degrees.

Malposition of the acetabular cup in THA is the most common cause of dislocation. To avoid errors in cup placement, computer navigation systems have been introduced and most of the navigation systems refer APP to establish cup orientation. There are two drawbacks in using APP as the reference. One is that apophyses such as ASIS develop variably in each patient with a resulting variability in APP tilt in the sagittal plane in supine. The other is significant changes in pelvis tilt during various activities of daily living such as standing, walking, and sitting. Therefore, even if cup orientation is acceptable when referencing APP, it can be mal-oriented in a functional position of the pelvis as in this case, which showed proper anteversion against APP but retroversion in supine, standing and sitting.

In conclusion, we found that there exists a case in which APP is not a suitable pelvic reference in determining orientation of the cup.

Introduction: In order to investigate the reparative reaction process in patients with osteonecrosis of the femoral head (ONFH), we performed tartrate resistant acid phosphatase (TRAP) staining for the femoral head retrieved from the patients at the surgery.

Methods: This study included 21 hips in 19 patients. There were 15 women and 4 men who had a mean age of 42 years (range, 22 to 79 years). Associated risk factors included corticosteroids (n=15), alcohol (n=4), and idiopathic (n=1). Radiologic staging according to the Japanese Orthopaedic Classification included one stage 1, six stage 3A (collapse < 3mm), five stage3B (collapse> 3mm), and nine stage 4 (osteoarthritic change). After femoral head samples were fixed in formalin, 15 samples were decalcified by EDTA, while 6 were not decalcified. All samples were stained by Haematoxylin and Eosin and TRAP.

Results: TRAP positive multinucleated cells were existed at not only necrotic trabecular bone but also new appositional trabecular bone. TRAP positive cells were mainly located at the reactive interface (revascularized) zone while they did not exist in the necrotic zone. They were sometimes located at the normal bone marrow area near the retinacula or teres. While subchondral fractures were detected in two stage 3A hips, five stage 3B hips, and three stage 4 hips, TRAP positive cells around the subchondral fracture were detected in only two stage 3B hips and three stage 4 hips. In one stage 1 hip, TRAP positive mononuclear cells were detected around the enlarged adipocytes at the reactive interface zone. In six stage 3A hips, TRAP positive cells were detected at the reactive interface zone just around the subchondral area. In five stage 3B hips, they were detected along the reactive interface zone in the femoral head. In nine stage 4 hips, they were detected through the subchondral area and along the reactive interface zone.

Discussion: The expression mode of TRAP positive cells changes according to the radiologic stages in ONFH, represents the reparative reaction process.

It has been noted that bony union of a pars defect can be achieved in children if they wear a trunk brace. Our aim was to evaluate how the stage of the defect on CT and the presence or absence of high signal change in the adjacent pedicle on T2-weighted MRI were related to bony healing. We treated 23 children conservatively for at least three months. There were 19 boys and four girls with a mean age of 13.5 years (7 to 17). They were asked to refrain from sporting activity and to wear a Damen soft thoracolumbosacral type brace. There were 41 pars defects in 23 patients. These were classified as an early, progressive or terminal stage on CT. The early-stage lesions had a hairline crack in the pars interarticularis, which became a gap in the progressive stage. A terminal-stage defect was equivalent to a pseudarthrosis. On the T2-weighted MR scan the presence or absence of high signal change in the adjacent pedicle was assessed and on this basis the defects were divided into high signal change-positive or -negative. Healing of the defect was assessed by CT.

In all, 13 (87%) of the 15 early defects healed. Of 19 progressive defects, only six (32%) healed. None of the seven terminal defects healed. Of the 26 high signal change-positive defects 20 (77%) healed after conservative treatment whereas none of the high signal change-negative defects did so. We concluded that an early-stage defect on CT and high signal change in the adjacent pedicle on a T2-weighted MR scan are useful predictors of bony healing of a pars defect in children after conservative treatment.

Introduction: The purpose of this study is to evaluate the clinical and radiogra phic outcome of patients with secondary osteoarthritis of the hip, who underwent custom-made cementless THA.

Methods: Between January 1994 and June 1997, 98 prim ary cementless custom-made THA’s were performed in 76 patients with secondary osteoarthritis and reviewed at mean 6 years follow-up (range: 4 – 7.5 years). Nine patients had a previous femoral osteotomy. There were 69 females and seven males. The mean age at operation was 54 years (40 – 73 years). Custom-made, 125 mm-long, titanium femoral components with blasted surface were fabricated based on the computerized tomography.

Results: The mean Harris Hip Score improved from 43 to 95 points. 97 patients (99%) had more than 80 points for total score, and 2 patients (2%) had thigh pain at the latest follow-up. Radiographically, 86 hips (87%) showed obviously extensive bone ongrowth onto the middle part of the stem while 8 hips (9%) showed stable fibrous fixation. Four hips (4%) were unstable: more than 2 mm subsidence in 2 hips and more than 2 degrees varus migration in 2 hips. Of these 4 hips, 2 had intraoperative cracks of the poximal femur and 2 had varus positioning of the stem.

Discussion and conclusion: Cementless THA has been advocated to enhance fit and fill of variable hip geometry. However, some clinical studies failed to show that custom implants significantly improve clinical success or implant longevity because their surface finish was not optimal. Custom-made titanium femoral components with blasted surface showed good clinical results. The reasons for radiolographical failures were because of intraoperative technical errors and these might be derived from 125 mm-long stem with maximum canal fill. A shorter stem may be an option because it may improve the feasibility of stem insertion and the distal fill.

Introduction: The purpose of this study was to evaluate clinical results of total knee arthroplasty with three different implants for patients with osteoarthritis (OA) and rheumatoid arthritis (RA) in our institution.

Materials and methods: From January 1993 to October 1998, 41 total knee arthroplasties were done at our institution. Clinical assessment was performed preoperatively and at most recent follow-up using the Japan Orthopaedic Association scoring system (JOA score). The Knee Society Radiological Evaluation System was used to evaluate a series of 41 total knee arthroplasties. The population consisted of 41 patients, 37 women and four men, with an average age of 71.8 (55-85) who had total knee arthroplasty, and the average BMI was 24.5 (18.1-36.0). Preoperative diagnoses were osteoarthritis in 25 patients and rheumatoid arthritis in 16 patients. Used implants were Miller-Garante 2 (Zimmer) in 15 knees, KU3 (Kyocera) in seven knees and Nexgen (Zimmer) in 19 knees.

Results: The average preoperative JOA score were 48.0 points and postoperative score were 74 points. Preoperative and postoperative maximum extension was −16.4 ± 10.9° and –2.86 ± 4.9°. Preoperative and postoperative maximum flexion was 105 ± 21.6° and 106 ± 15.0°. On the AP radiographs, the average angulation of the femoral component was 96.9 ± 2.2° and tibial component position was 88.0 ± 2.5°. The lateral radiographs revealed an average femoral component flexion of 3.03 ± 3.9° The average tibial component flexion was 3.53 ± 3.02°. And there was no significant difference in radiographic evaluation among those implants.

Conclusion: In the middle term results, there was a significant correlation between preoperative and postoperative flexion and a significant improvement of maximum extension of the knee after total knee arthroplasty.

Introduction: In order to investigate the relationship between the degeneration of the acetabular cartilage and the radiological staging of osteonecrosis of the femoral head, the following study was performed.

Materials and Methods: Acetabular cartilage with sub-chondral bone was taken from the superior dome from 34 hips from 30 patients undergoing total hip arthroplasty due to osteonecrosis of the femoral head. The specimens were stained with hematoxylineosin and safranin-O, and were evaluated as to the thinning of cartilage, fibrillation, clefts, and proliferation of chondrocytes. There were 18 females and 12 males with an average age of 49 years. We used the radiological staging system proposed by the working group of the Specific Disease Investigation Committee under the auspices of the Japanese Ministry of Health, Labor and Welfare. There were eight hips in stage IIIA disease (collapse of the femoral head less than 3 mm), 19 hips in stage IIIB disease (collapse 3 mm or greater), and seven stage IV disease hips.

Results: All 34 specimens showed histological abnormalities. In eight stage IIIA hips, six hips were mild and two were moderate histological degeneration. In 19 stage IIIB hips, five hips were mild, six were moderate, and eight had severe arthrosis. Seven stage IV hips had severe arthrosis.

Discussion: Although the radiographs cannot demonstrate early degeneration of cartilage, degenerative changes were present in all stage III hips. Histological degenerative changes in stage IIIB hips were more severe than those in stage IIIA hips. These findings should be kept in mind in treating patients with osteonecrosis of the femoral head.

Between 1995 and 1999, 12 patients aged 65 years or more (mean 70.2) with lumbar disc herniation, underwent partial laminectomy and nucleotomy. The results were compared with those of 25 younger patients aged between 20 and 40 years (mean 30.1), who underwent the same surgical procedure. The Japanese Orthopedic Association (JOA) score was used to assess the clinical outcome. The minimum follow-up was 12 months. The pre- and post-operative total JOA scores and the rate of improvement of the JOA score were not significantly different between the elderly (11.1, 24.3 points, and 74.1%), and the younger group (11.6, 26.4 points and 84.5%).

The results of this study indicate that the outcome of lumbar discectomy in elderly patients is as good as in younger patients.

Open reduction for developmental dislocation of the hip (DDH) is invasive and sometimes results in femoral head deformity while open reduction has been the first choice in case non-operative reduction is failed in.

We treated 3 patients with 3 affected hips using minimum invasive arthroscopic reduction method. Pre-operative MRIs represented these 3 hips had obstruction of interposed thick limbus. The average age of patients treated by this method was 23 months.

This method consists of arthrogram, arthroscopic limboplasty, and arthroscopic reduction. This series of maneuvers was able to lead unreducable hips to the reduction position.

Post-operative MRIs represented that the interposed thick limbus had been removed to the outside of acetabulum and the limbus covered the reduced femoral head. There were no signs of residual subluxation of the hips in radiographic examination.

This new minimum invasive arthroscopic reduction method have a possibility to take the place of the invasive open reduction in the treatment of DDHs with obstruction of interposed thick limbus.

Objective: The objective was to evaluate mortality and ambulatory ability for elderly patients over 80 years with a femoral neck fracture treated surgically. A strategy for managing elderly patients with various problems is proposed.

Materials and Methods: From January 1, 1998 to March 31, 1999, 122 patients with femoral neck fractures were treated in our hospital. Sixty patients aged over 80 years were chosen from this series for the present study. The 60 patients included 50 women and 10 men with a mean age of 87.1years (range 80–97years). The fractures included 26 intracapsular and 34 extracapsular fractures. The mean follow-up period was 12.9 months. The patients were classified into three groups according to age: group A (80–84 years old), group B (85–89 years old) and group C (over 90 years old). The following parameters were evaluated: duration between injury and operative treatment, duration of hospital stay, senile dementia, prefracture and postoperative walking abilities, and mortality. Walking ability was graded on a scale of 0–4: 0, free gait; 1, gait with a walking stick; 2, gait with a wheelchair; 3, ability only to walk a few steps; and 4, bedridden.

Results: The rates of regained postoperative walking ability to better than grade 2 were 72.2% (13/18) in group A, 65.2% (15/23) in group B and 84.2% (16/19) in group C. These patients were followed until death or for at least one year. The overall mortality rates were 11.1% (2/18) in group A, 17.4% (4/23) in group B and 10.5% (2/19) in group C.

Conclusion: In cooperation with internists, medical staff and family members, we were able to overcome various problems and achieve good clinical outcomes. Cooperation of family members was needed for the elderly patients to return to where they had lived before the trauma and to improve their quality of life.

Objective: To compare the functional results with the anatomical results of treatment for fractures of the distal end of radius in patients aged over 60 years.

Methods: The results of treatment for fractures of the distal end of radius in 25 elderly patients were evaluated retrospectively. The average age of the patients was 70 years and the average follow-up period was 24 months. Twenty-one fractures were treated by percutaneous pinning, two were treated with plates, and two were treated conservatively. All patients were right-handed. The functional results were evaluated according to the sum of demerit points (Saito, 1983), and the following three parameters were used for evaluation of anatomical results: radial tilt, ulnar variance, and palmar tilt.

Results: The latest follow-up functional end results were excellent in 52 % of the fractures and good in 48%. In the final radiographs, the average radial tilt was 20.5 degrees, ulnar variance was 3.7 mm, and palmar tilt was 2.5 degrees. The values of ulnar variance and palmar tilt were often found to be out of the normal range. Most of the patients had a satisfactory outcome, and the functional results were not correlated with the magnitude of residual deformities. Grip power was the most significant factor related to subjective evaluation. Grip power recovered 75.2 % of uninjured side grip power in patients fractured left hands and 103.4 per cent in patients fractured right hands. This difference was significant (p< 0.05).

Conclusions: A good functional outcome of treatment for fractures of the distal end of radius in elderly patients can be expected irrespective of radiographic evidence of minor deformities.