Rotational Acetabular Osteotomy for Osteoarthritis with Acetabular Dysplasia: Conversion Rate to Total Hip Arthroplasty within Twenty Years and Osteoarthritis Progression After a Minimum of Twenty Years.

BACKGROUND: We investigated the rate of conversion to total hip arthroplasty by twenty years and radiographic findings at a minimum of twenty years after rotational acetabular osteotomy. METHODS: Between June 1986 and August 1991, we performed 172 rotational acetabular osteotomies in 168 patients with acetabular dysplasia. Of those, ninety-three hips (ninety-one patients), including twenty-three hips with pre-osteoarthritis, twenty-nine with initial osteoarthritis, and forty-one with advanced osteoarthritis, had clinical and radiographic findings available. The mean age of the patients was 32.4 years (range, twelve to forty-nine years). The duration of follow-up was a mean of twenty-three years (range, twenty to twenty-seven years) for seventy-six hips, excluding hips that underwent conversion to total hip arthroplasty. RESULTS: Conversion to total hip arthroplasty by twenty years after surgery was performed in one hip (4%) with pre-osteoarthritis, two hips (7%) with initial osteoarthritis, and fourteen hips (34%) with advanced osteoarthritis. The hips with advanced osteoarthritis had a significantly higher rate of conversion to total hip arthroplasty than hips in the other stages did (p = 0.0005). At the latest follow-up or at conversion to total hip arthroplasty, the disease stage had not progressed in seventeen hips (74%) with pre-osteoarthritis, nineteen (66%) with initial osteoarthritis, and twenty-six (63%) with advanced osteoarthritis. CONCLUSIONS: The progression of osteoarthritis after rotational acetabular osteotomy was not detected for at least twenty years in most hips with either pre-osteoarthritis or initial osteoarthritis in this cohort. Rotational acetabular osteotomy may delay conversion to total hip arthroplasty in advanced osteoarthritis. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Does rotational acetabular osteotomy affect subsequent total hip arthroplasty?

INTRODUCTION: Rotational acetabular osteotomy (RAO) has been used successfully in patients with developmental dysplasia of the hip (DDH). However, some patients are forced to undergo total hip arthroplasty (THA) because of the progression of osteoarthritis. We evaluated the effect of previous RAO on the outcome of THA performed for degenerative arthritis secondary to DDH, comparing outcomes for patients with THA and prior RAO versus outcomes for patients with THA and no prior RAO. MATERIALS AND METHODS: At an average follow-up point of 8.2 years (range 7-11 years), we compared outcomes in dysplastic hips for 22 hips (group R) in patients who underwent THA after successful RAO with outcomes for a well-matched control group of 30 hips in patients who underwent primary THA (group C) during the same period. RESULTS: Both groups had similar midterm results. No acetabular or femoral components exhibited loosening or revision in either group. Harris hip scores (HHSs) at the most recent follow-up had not been compromised by RAO, and there were no significant differences in intraoperative blood loss and operative time between the two groups. Although there was a tendency toward superolateral placement of the acetabular component in group R, there were no significant differences in the mean steady-state linear and volumetric wear rates between the two groups. There were no infections, dislocations, intraoperative fractures, damaged nerves, or deep vein thromboses in either group. CONCLUSIONS: Our midterm results demonstrated that RAO does not lead to higher revision rates, compromised HHSs, or shortened survivorship in eventual THA for DDH.

Bone remodeling after a mean of 10 years in diaphyseal cortical defects repaired with femoral revision using bypass fixation of extensively porous-coated stems with high stiffness.

INTRODUCTION: Femoral component revisions with extensively porous-coated stems have shown promising clinical results, although there are still concerns over stress-shielding. MATERIALS AND METHODS: We retrospectively reviewed data for 18 patients undergoing femoral component revisions with extensively porous-coated stems with high stiffness. The average length of follow-up was 10 years (range 6-13.7 years). RESULTS: Radiographic evidence of a bone-ingrown stem was present in 94 % of the hips, and stable fibrous fixation was present in only one hip, but no hips were considered unstable. There was mild stress-shielding in 15 hips, moderate stress-shielding in one hip, and severe stress-shielding in two hips. In one of the latter two hips, stress-shielding was progressive even 8 years after revision surgery. In 12 (92 %) of the 13 hips in which bypass fixation for diaphyseal cortical defects was used, there was good remodeling. CONCLUSIONS: We suggest that femoral component revision using extensive porous-coated stems is a useful option that may allow for healing of diaphyseal cortical defects.

Clinical assessment after total hip arthroplasty using the Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire.

AIMS: The aim of this study was to evaluate clinical outcomes using the Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire (JHEQ). METHODS: 100 consecutive patients at 6 months after total hip arthroplasty (THA) were evaluated. RESULTS: The improvement rate for the pain subscale was significantly higher than that for the movement and mental subscales. Preoperative scores on the JHEQ movement and mental subscales were positively correlated to scores on the same subscales at 6 months after surgery. CONCLUSION: We conclude that the most predictable aspect of THA is pain relief and preoperative hip-joint ROM and mental status influence 6-month postoperative outcomes.

Retrieval analysis of new-generation yttria-stabilized zirconia femoral heads after total hip arthroplasty.

Zirconia femoral heads were introduced for total hip arthroplasty (THA) with the expectation of lower polyethylene (PE) wear and better clinical results. Because several studies reported poor survivorship of yttria-stabilized zirconia-PE THA, we investigated a new-generation yttria-stabilized zirconia head (diameter, 26 mm) manufactured by NGK Spark Plug. We retrieved six zirconia heads at revision THA after they had been in place for a mean of 8.6 years and measured their surface roughness and mean monoclinic content. Although their mean monoclinic content was higher than that of the unused head, surface roughness in the implanted heads was as low as that of the unused head, indicating that wear reduction may be possible with the selection of a suitable zirconia femoral head.

Cementless anatomic total hip femoral component with circumferential porous coating for hips with developmental dysplasia: a minimum ten-year follow-up period.

Anatomic femoral components are optimized for primary osteoarthritis, and few long-term results for their use are available for developmental dysplasia of the hip (DDH). We reviewed 135 uncemented total hip arthroplasties in which an anatomic femoral component was used in 106 patients with DDH, excluding femurs with neck-shaft angles of >160° and femurs with anteversion of >50°. The mean age of patients at surgery was 49.4 years (range, 33-66 years), and the mean duration of follow-up was 13.5 years (range, 10-18 years). No osteoporotic femurs were included in our study group. Despite 18 acetabular revisions, no femoral component was removed for any reason. No femoral loosening was seen at the final follow-up examination. An anatomic femoral component with circumferential porous coating can produce good clinical and radiologic findings in young patients with good bone quality who have DDH without excessive femoral deformity.

How far above the true anatomic position can the acetabular cup be placed in total hip arthroplasty?

INTRODUCTION: There is controversy about which is more suitable for determining correct socket position in patients with severe bone deficiency of the acetabular roof because of developmental dysplasia of the hip (DDH): the anatomic centre of hip rotation or a high centre. 
 METHOD: We evaluated the relationship, in 200 hips, between the centre of rotation and presence of the Trendelenburg sign to determine the upper limit of cup position from the standpoint of hip-abductor strength. 
 RESULTS: Of the 200 hips, 20 (10%) showed a positive Trendelenburg sign. There were no statistically significant differences between parameters (the centre of rotation, femoral offset, abductor lever arm) regarding the presence of the Trendelenburg sign except for age at surgery. Patients with a positive Trendelenburg sign were significantly older (64.1 ± 9.4 years) than those with a negative Trendelenburg sign (58.8 ± 7.7 years) (P = 0.01).
 CONCLUSIONS: Our findings indicate that a high centre of hip rotation of up to approximately 30 mm from the inter-teardrop line is a feasible option for patients with DDH from the standpoint of hip-abductor strength if stems are used that allow the restoration of femoral offset and the abductor lever arm.

Wear comparison between conventional and highly cross-linked polyethylene against a zirconia head: a concise follow-up, at an average 10 years, of a previous report.

We previously reported the results of wear comparison at a minimum of 5 years between highly cross-linked polyethylene (HXLPE) and conventional polyethylene (PE) against a zirconia femoral head. We now report the mean wear at 10 years for 52 patients (56 hips) of the original cohort of 61 patients (65 hips) who had undergone primary total hip arthroplasty at our hospital between November 1999 and August 2000. The mean steady-state linear wear rate of HXLPE was 0.045 mm/y, compared with 0.080 mm/y for conventional PE (P=.0003). The incidence of osteolysis was 25% in the conventional PE group compared with 0% in the HXLPE group. Our study demonstrated that the steady-state wear rate for HXLPE remains significantly lower than that for conventional PE against a zirconia femoral head at a mean of 10 years after implantation.

A radiological study of the true anatomical position of the acetabulum in Japanese women.

There is sometimes uncertainty concerning the correct socket position prior to total hip arthroplasty (THA). We conducted a study to determine the hip centre in Japanese women in order to define the true anatomical position of the acetabulum. The study involved 200 consecutive female patients in whom the contralateral hip joint was normal or was prearthritic and who underwent unilateral THA. The 'normal' group comprised 100 hip joints with no acetabular hip dysplasia, and the prearthritis group comprised 100 hip joints with Crowe type I dysplasia. The length of a perpendicular line drawn under the teardrop (interteardrop line) connecting both inferior edges of the teardrop with the centre of the femoral head was recorded as the vertical distance, and the distance from the intersection of the perpendicular line and interteardrop line up to the teardrop was recorded as the horizontal distance. We measured these distances on the femoral head of the side that did not undergo THA. The mean vertical distances in the 'normal' and prearthritis groups were 14.6 ± 2.8 mm and 16.8 ± 2.7 mm, respectively, and the mean horizontal distances were 30.2 ± 2.8 mm and 32.5 ± 2.7 mm, respectively. We therefore determined the mean centre of the hips to lie at a vertical distance of 11 to 22 mm and a horizontal distance of 27 to 38 mm. These values can serve as a useful index for socket positioning in THA.

Osteoarthritis hip joints in Japan: involvement of acetabular dysplasia.

BACKGROUND: We conducted a nationwide epidemiologic study regarding hip osteoarthritis (OA) in Japan, and a previous report found these patients to be unique in comparison to Caucasians. This report focused on the data regarding each hip joint, and the involvement of acetabular dysplasia with hip OA was analyzed. METHODS: Seven hundred twenty OA hips were examined. Sixty-five joints with osteonecrosis of the femoral head and 215 non-OA contralateral joints of the unilateral patients were examined as controls. The revised system of stage classification for hip OA of the Japanese Orthopedic Association (JOA) was used according to the reproducibility in order to ensure reliable data from the multiple institutions. The acetabular dysplasia indexes were also chosen according to the reproducibility and measured in the radiograph of bilateral hip joints. The clinical score was assessed using the JOA scoring system. The relative risk of the grade of acetabular dysplasia indexes for hip OA was calculated as the odds ratio and the 95% confidence interval. RESULTS: The stage of the OA joints deteriorated with increasing age. The clinical scores also decreased. The grade of the acetabular dysplasia indexes of the OA joints was significantly higher than that of the control joints. Each index of acetabular dysplasia demonstrated significantly increased odds ratios for hip OA. Among the OA joints, the deterioration of the OA stage was found to be significantly associated with an increasing grade of acetabular dysplasia. The odds ratio for OA deterioration in the acetabular dysplasia index was also obtained. The joints of females tended to have a higher grade and prevalence of acetabular dysplasia than those of males. CONCLUSIONS: These findings confirmed a high prevalence of acetabular dysplasia in hip OA joints in Japan. Acetabular dysplasia was one of the most important factors associated with hip OA.

Should the well-fixed, uncemented femoral components be revised during isolated acetabular revision?

INTRODUCTION: The results of isolated acetabular revision performed in 35 patients (36 hips) were monitored from 3 to 10 years. All femoral components were well fixed and not removed or revised during index surgery. METHOD: All revision acetabular implants were cementless, using a porous-coated hemispheric cup with or without bone graft. There were no cases of femoral component radiographic or clinical failure. For some cases, we performed bone grafting to focal osteolysis of the proximal femur around the cementless stem. RESULTS: Bone incorporation occurred in 12 hips (overall 14). The mean pre- and postoperative Harris Hip Scores were 49 and 80, respectively. The findings suggest that isolated acetabular revision using a cementless porous-coated hemispheric cup can be performed without removing or revising a stable, well-fixed, uncemented femoral component if there is no concern about dislocation. CONCLUSION: We demonstrated that isolated acetabular revision is feasible and that grafting to the osteolytic femoral defects is a worthwhile procedure to restore bone stock.

Wear comparison between a highly cross-linked polyethylene and conventional polyethylene against a zirconia femoral head: minimum 5-year follow-up.

Highly cross-linked polyethylene (HXLPE) was developed to reduce wear of articular bearing surface in total hip arthroplasty patients. Several studies have shown reduced wear of HXLPE compared with conventional polyethylene; however, these studies had used HXLPE in combination with a Co-Cr metal head. The purpose of this study was to compare the 5-year in vivo wear of HXLPE with that of conventional PE using a zirconia femoral head. Forty-five hips with a Trilogy HXLPE (Zimmer, Warsaw, Ind) were matched and compared with a control group of 20 conventional Trilogy PE hips. The 2-dimensional linear wear rate was significantly less in the HXLPE group between 1 and 5 years postoperation (P < .001). The results show that HXLPE reduces short-term polyethylene wear against not only a Co-Cr head but also a zirconia head.

Prevention of steroid-induced osteonecrosis by intravenous administration of vitamin E in a rabbit model.

BACKGROUND: We focused on vitamins with marked antioxidant potency to see whether their use might prevent the development of steroid-induced osteonecrosis. METHODS: Fifteen Japanese white rabbits weighing about 3.5 kg were injected once into the right gluteal muscle with methylpred-nisolone (MPSL) 40 mg/kg (S group). In addition, 10 other rabbits received consecutive daily intravenous injections of vitamin E 50 mg/kg, starting from the day of MPSL administration (E group). All animals were killed 2 weeks after MPSL administration, and femurs were extracted and stained with H&E. Blood levels of reduced glutathione (GSH) were also measured. RESULTS: In the S group the osteonecrosis development rate was 93%, in contrast to 0% in the E group (P < 0.01). Also, GSH levels in the S group abruptly decreased from the first day after MPSL administration, whereas in the E group, the decline in GSH levels was significantly suppressed on days 1 and 3 after MPSL administration (P< 0.05). CONCLUSIONS: Vitamin E administration significantly inhibited steroid-induced oxidative stress. The results of this study suggest that the administration of vitamin E may be a novel and simple method to prevent the development of steroid-induced osteonecrosis.

Analysis of interobserver reliability for radiographic staging of coxarthrosis and indexes of acetabular dysplasia: a preliminary study.

BACKGROUND: We are planning a multicenter survey on coxarthrosis and acetabular dysplasia in Japan. To collect reliable data, we performed a preliminary study to elucidate the observer agreement on assessment items. METHODS: We collected radiographs of hip joints in eight patients with various findings of coxarthrosis. Twelve registered orthopedic specialists evaluated them regarding the roentgenographic stage of coxarthrosis and five indexes of acetabular dysplasia (acetabular angle, center-edge angle, acetabular roof obliquity, acetabular head quotient, approximate acetabular quotient). To assess observer agreement, we calculated the value of the kappa statistic for stages and the coefficient of variation for the indexes. The same 12 specialists then assessed the coxarthritis stage on the same radiographs 1 month after the first evaluation based on our own descriptions of the roentgenographic stages. RESULTS: For the first evaluation of the roentgenographic stage, the value of the kappa statistic was 0.448; and for the second evaluation it was 0.600. The results of the coefficient of variation for the indexes of acetabular dysplasia, ranked in ascending order, were as follows: acetabular angle, acetabular head quotient, acetabular roof obliquity, center-edge angle, approximate acetabular quotient. CONCLUSIONS: For the upcoming multicenter survey, clear descriptions of the stages of coxarthrosis and selection of appropriate indexes can be helpful for collecting dependable results.

A new cementless total hip arthroplasty with bioactive titanium porous-coating by alkaline and heat treatment: average 4.8-year results.

A method has been developed for creating a bioactive coating on titanium by alkaline and heat treatment, and shown that it forms a thin layer of hydroxyapatite (HA) on the surface of implants when soaked in simulated body fluid. A series of 70 cementless primary total hip arthroplasties using this coating technique on a porous titanium surface was performed, and followed up the patients for a mean period of 4.8 years. There were no instances of loosening or revision, or formation of a reactive line on the porous coating. Although radiography just after operation showed a gap between the host bone and the socket in over 70% of cases, all the gaps disappeared within a year, indicating the good osteoconduction provided by the coating. Alkaline-heat treatment of titanium to provide a thin HA coating has several advantages over plasma-spraying, including no degeneration or absorption of the HA coating, simplicity of the manufacturing process, and cost effectiveness. In addition, this method allows homogeneous deposition of bone-like apatite within a porous implant. Although this was a relatively short-term study, treatment that creates a bioactive surface on titanium and titanium alloy implants has considerable promise for clinical application.

Minimum ten-year results of a porous acetabular component for Crowe I to III hip dysplasia using an elevated hip center.

We conducted a retrospective study of the placement of porous-coated acetabular components using screws at more than 20 mm above the teardrop without structural bone graft for dysplastic hips to determine long-term outcome. Thirty hips (29 patients) were monitored for a mean of 15.2 years (range, 10.4-18.3 years) after surgery. Compared with 12 contralateral normal hips, the distance of the hip center from the teardrop was significantly high (26.8 +/- 4.8 and 13.4 +/- 2.7 mm P < .001); however, it was not laterally different (31. 5 +/- 5.1 and 31.7 +/- 5.0 mm). No acetabular components showed loosening. One metal shell was revised for wear and osteolysis. Morselized bone grafted in 25 hips was incorporated in all cases. Slight elevation of the hip center without lateralization in cementless cups fixed with screws was well tolerated for dysplastic hips.

Revision total hip arthroplasty by nonmodular short and long cementless stems.

BACKGROUND: The choice of appropriate implant for reconstruction during revision total hip arthroplasty (THA) is controversial. We use proximally porous-coated cementless short stems and fully porous-coated cementless long stems depending on the state of bone loss during revision surgery. METHODS: Between January 2000 and December 2003, a total of 21 cementless femoral revision arthroplasties using cementless stems were performed, and 20 of the cases were followed up for 2-6 years (mean 4.3 years). Proximally porous-coated cementless short stems were used in 5 cases with minimum bone loss, and fully porous-coated cementless long stems were used in 15 cases with metaphyseal bone loss. RESULTS: All stems were radiographically stable at the final follow-up. No osteolysis or loosening was seen. None of the patients needed re-revision femoral surgery. Metaphyseal bone loss dramatically diminished in six of nine patients with bypass fixation of the defect lesion by long stems. Bone remodeling of the lost bone occurred in an additional four cases. The mean preoperative Harris Hip Score was 52.7 points, and at the final follow-up examination it was 79.6 points. CONCLUSIONS: Femoral reconstruction during revision THA by short and long cementless stems depending on the degree of bone loss produced a good outcome. To assess long-term durability, it is necessary to follow these cases carefully.

Component alignment in revision total knee arthroplasty using diaphyseal engaging modular offset press-fit stems.

We performed a retrospective study of the radiographic position of femoral and tibial components in a series of revision total knee arthroplasties using diaphyseal-engaging, press fit, modular stems. Fifty-two consecutive revision cases were performed. Femoral and tibial component alignment was measured preoperatively and postoperatively. The canal-filling ratio was measured and correlated with anatomic alignment. There was a trend toward improved alignment with increasing canal fill, suggesting that uncemented diaphyseal engaging press-fit modular stems facilitate accurate alignment for both femoral and tibial components in revision surgery.

[Oxidative stress on idiopathic osteonecrosis].

The increasing incidence of steroid-induced osteonecrosis of the femoral head is a recent and emerging problem. In-depth pathogenesis, however, has not been well understood. We focused on oxidative stress, which was reported to be involved in many diseases, and conducted animal studies to investigate it. Our results from the rabbit model of steroid-induced osteonecrosis demonstrated that administration of steroids caused oxidative damage in bones, and the administration of glutathione reduced the incidence of osteonecrosis. We were also the first to have successfully induced osteonecrosis in rats by administering buthionine sulfoximine (BSO) . The results indicated the involvement of oxidative stress in the development of osteonecrosis and may contribute to elucidating the underlying mechanisms and prevention of the pathogenesis of steroid-induced osteonecrosis.