Introduction

The anatomic abnormalities are observed in developmental dysplasia of the hip (DDH) and it is challenging to perform the total hip arthroplasty (THA) for some DDH patients. If acetabular cup was placed at the original acetabular position in patients with high hip dislocation, it may be difficult to perform reduction of hip prosthesis because of soft tissue contracture. The procedures resolving this problem were to use femoral shortening osteotomy, or to place the acetabular cup at a higher cup position than the original hip center. Femoral shortening osteotomy has some concerns about its complicated procedure, time consuming, and risk of non-union. Conversely, implantation of the acetabular cup at the higher cup position may eliminate these shortcomings and this procedure is considered to be preferred if possible. However, the criteria of cases without femoral shortening osteotomy are not clear. In this study, we retrospectively analysed the clinical outcomes of patients performed THAs for high hip dislocation, and clarified the adaptation of THA with or without femoral shortening osteotomy.

Aims

The purpose of this study was to compare two different types of metal-on-metal (MoM) bearing for total hip arthroplasty (THA): one with a large femoral head (38 mm to 52 mm) and the other with a conventional femoral head (28 mm or 32 mm). We compared clinical outcome, blood metal ion levels, and the incidence of pseudotumour in the two groups.

The purposes of this study were to review retrospectively the 25-year survival of cemented and cementless THA for hip dysplasia and to compare the effect of fixation methods on the long-term survival in patients with DDH. We retrospectively reviewed all patients with OA secondary to hip dysplasia treated with a cemented Bioceram hip system between 1981 and 1987, and a cementless cancellous metal Lübeck hip system between 1987 and 1991. The studied subjects were 76 hips of cemented THA (Group-C) and 57 hips of cementless THA (Group-UC). Both hip implants had a 28-mm alumina head on polyethylene articulation. The mean age at operation was 50.5 years (range, 36–60 years) in Group-C and 50.0 years (range, 29–60 years) in Group-UC. The survival at 25 years regarding any revision as the endpoint was 46% in Group-C and 76% in Group-UC. These difference was significant using Log-rank test (P=0.008). The cup survival at 25 years was 47% in Group-C and 83% in Group-UC (P= 0.0003). The stem survivals at 25 years were 95% in Group-C and 92% in Group-UC. (P= 0.416). Cementless THA in patients with DDH showed a higher survival rate at 25 years than cemented THA because of the excellent survival of the acetabular component without cement. We conclude that cementless THA with the cancellous metal Lübeck hip system led to better longevity at 25 years than cemented THA with the Bioceram in patients with OA secondary to DDH.

INTRODUCTION

To obtain appropriate joint gap and soft tissue balance, and to correct the lower limb alignment are important factor to achieve success of total knee arthroplasty (TKA). A variety of computer-assisted navigation systems have been developed to implant the component accurately during TKA. Although, the effects of the navigation system on the joint gap and soft tissue balance are unclear. The purpose of the present study was to investigate the influence of accelerometer-based portable navigation system on the intraoperative joint gap and soft tissue balance.

Introduction

Metal on metal hip resurfacing (MoM HR) is attractive for young active patients. Patients with osteonecrosis of the femoral head (ONFH) are relatively young. HR can be an option of treatment, however, long-term stability of the femoral component is a concern because of the necrotic lesion in the femoral head. There is also a concern of ARMD for MoM implants. The purpose of this study is review a 10 year outcome of a consecutive patients with ONFH who underwent MoM HR.

INTRODUCTION

The concept of anatomical stam is fit-and-fill in the proximity of the femur and to expect wall fixation, following to reduce thigh pain and stress shielding. Although the femoral medullary form and size are different in each races. CentPillar TMZF stem (stryker ^®) is anatomical stem designed based on computer-tomography of Japanese femurs. The purpose of this study was to evaluate clinical and radiographic outcomes of CentPillar TMZF stem at a mean of 3.6 years postoperatively.

The Taperloc Microplasty stem design was based on that of the Taperloc stem with flat tapered wedge and the distal portion of the Taperloc stem was shortened by 35mm.

We report the minimum two-year follow up (mean, 26 months) of 68 primary total hip arthroplasty using the Taperloc Microplasty stem. 39 Magnum acetabular cups and 29 M2a Taper acetabular cups were inserted with metal on metal articulation. The series comprised 67 patients (20 men, 47 women) with a mean age at operation of 65 years (31 to 85). The principal diagnosis was osteosrthritis.

Their mean JOA Hip Score improved significantly from 36 points preoperatively to 96 points at two-year follow up. Radiological asseement showed good bony stability in all implants. There was one case of post operative anterior dislocation. We did not see intra-operative fracture previously reported for this implant. There were no clinical and radiological complications related to MOM articulation.

This short-term follow up study demonstrates that the clinical outcome of the Tapeloc Microplasty stem is comparable with that of standard Taperloc stem and other flat taper wedge stems.

Metal on metal total hip arthroplasty (MoM THA) provides the potential improvement in articular wear. However, several adverse events including pseudotumor had been reported. Magnetic resonance imaging (MRI) was considered to be the proposal tool for detection of pseudotumor after MoM THA. In this study, we performed the screening of pseudotumor after MoM THA using the MRI.

We studied 43 patients with M2a Magnum® (Biomet) and 34 patients with M2a Taper® (Biomet) of MoM THA from December 2009 to December 2011 with follow-up of 2.5 years (2.0–4.0 years) after surgery. MRI assessments were performed at a mean of 2.1 years postoperatively. Pseudotumor findings were graded using Anderson classification (Skeletal Radiol, 2011: 40; 303). Age, sex, height, weight, Harris Hip Score, EQ5D satisfaction score, UCLA activity score, and blood metal ion levels were evaluated.

The prevalence of pseudotumor was 27.2%; 56 normal (Type A), 13 mild (C1), 8 moderate (C2) and none were graded severe (C3). Weight and BMI in the mild group was significantly higher than those in normal. There was no significant difference in age, sex and height among these groups. With regard to Harris Hip score, pain and ROM score in moderate group was significantly lower than that in normal and mild group. EQ5D satisfaction score and UCLA activity score showed not significant differences among groups. 3.01±3.32 μg/L of blood cobalt ion levels in the moderate groups was significantly higher than 0.97±0.64 μg/L in normal group. Blood cobalt ion levels of 1 mild and 2 moderate were over the threshold of 7 μg/L. These patients were implanted with M2a Taper, not M2a Magnum. 14% of the prevalence in the patients with M2a Magnum was significantly lower than 41% in the patients with M2a Taper. No revision surgeries were required.

The patients with no pseudotumor did not show the increase of blood metal ion. Contrarily, several patients showed the increase of blood metal ion in case of detecting pseudotumor. MRI assessments were useful for screening of pseudotumor after MoM THA and blood metal ion should be investigated for patients with mild and moderate pseudotumor in MoM THA.

Modulus femoral prosthesis is a modular cementless femoral system which consists of 5 degree tapered conical stem made of a titanium alloy with 8 fins of 1mm and modular neck. Modular neck enables to control any ideal stem anteversion as a surgeon prefers. This system is considered to be useful in severe hip deformity, for example developmental dysplasia of the hip (DDH). In this study, clinical and radiographic outcomes of the Modulus femoral prosthesis were evaluated at a mean of 3.6 (2–6) years postoperatively.

We assessed the results of 193 primary total hip arthroplasty using a Modulus femoral prosthesis in 169 patients (15 males, 154 females) undergoing surgery between September 2007 and December 2011. The mean age at the time of surgery was 65.6 (31–86) years old. The diagnoses were osteoarthritis (OA) in 178 hips (including 167 hips of DDH), rapidly destructive coxopathy (RDC) in 6 hips, rheumatoid arthritis (RA) in 6 hips, osteonecrosis in 2 hips, and subchondral insufficiency fracture in one hip. Clinical outcomes were assessed using Japan Orthopedic Association (JOA) hip scores and complications. Radiographic assessments were including stem alignment, bone on-growth, cortical hypertrophy, stress shielding and stem subsidence.

43.8 points of the preoperative mean JOA score was significantly improved to 93.1 points postoperatively. In one case intraoperative femoral fracture was occurred. One dislocation had occurred and thigh pain was observed in one hip. No revision surgery was required. In 192 hips of 193 hips (99.5%), stem was implanted in neutral position (within ±2 degrees). Bone on-growth was observed in all cases (94.3% in zone 3; 73.1% in zone 5; 30.6% in zone 2; 22.3% in zone 6). Cortical hypertrophy was observed in 66 hips (34.2%) at zone 3 and 5. Reduction of bone density due to stress shielding was observed (1^st degree was 58.5%; 2^nd degree was 29.5%; 3^rd degree was 11.9%; 4^th degree was 0%). In 22 cases (11.4%), more than 2mm of stem subsidence was observed, however the subsidence was stopped within 6 months in all cases.

Modulus femoral prosthesis showed good clinical results and radiographic findings up to 6 years postoperatively.

Metal on metal total hip arthroplasty provides the potential improvement in articular wear and the use of large-diameter femoral heads following the prospect for reduction in the risk of dislocation. The purpose of this study was to compare the clinical and radiographic outcomes as well as serum metal ion level between the two different component designs with small and large femoral heads in metal on metal total hip arthroplasty.

We studied 39 patients with large head (Magnum®, Biomet; cup size minus 6 mm) and 37 patients with small head (M2a taper®, Biomet; 28 or 32 mm head) of metal on metal total hip arthroplasty between December 2009 to October 2011 with follow-up of 2.1 years (1.0–3.3 years) after surgery. Harris Hip Score, UCLA activity score, EQ-5D, radiographic assessment, and serum cobalt and chromium ion levels were evaluated.

Harris Hip Score, UCLA activity score, and EQ-5D were improved after surgery in small and large head groups, however, no significant differences were observed between both groups. Cup inclination was below 50 degree in all prosthesis. No loosening and no osteolysis were observed. Cobalt and chromium ion was not detected before surgery; however, metal ion levels of both groups were increased after surgery in time dependent manner. There was no significant difference between two groups at one year after surgery. One patient in each group showed the increase of cobalt ion level over 7 ppb (15.4 ppb, 12.9 ppb) without any clinical symptom including pain. Cup inclination was 29 degree in both patients and cup anteversion was 38 and 41 degree, respectively.

There was no significant difference of ion levels between both groups. No dislocation was observed in large head group while one dislocation occurred in small head group. No patients required the revision surgery.

This metal on metal component, especially with large femoral heads, showed the good clinical results at the maximum follow up of 3.3 year after surgery. However, the ion level of two patients increased over 7 ppb and longer follow-up will be needed.

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.

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.

The range of motion (ROM) after total knee arthroplasty (TKA) is one of the most important factors for patient satisfaction, especially in Asian countries. To enhance the knee flexion angle, “high-flexion” designs have been introduced in total knee prostheses. One of such design was a new design of femoral prosthesis, which increased the posterior cut on the bone by 2 mm and thickened the posterior condyle, allowing the posterior condylar radius to continue further. There were several reports on postoperative ROM of such “high-flexion” posterior-stabilized (PS) total knee prosthesis. However, there was no report on the postoperative ROM of “high-flexion” cruciate ligament retaining (CR) total knee prosthesis. The purpose of this study was to compare the ROM associated with standard and high-flexion posterior CR total knee prostheses.

One hundred and fifty-one consecutive patients (176 knees) had CR total knee prosthesis. 89 knees had standard CR TKA (NexGen CR, Zimmer, Warsaw, IL), and 87 knees had high-flexion CR knee prostheses (NexGen CR-Flex, Zimmer, Warsaw, IL). Differences in the age, diagnosis, preoperative Knee Society Score (KSS), and preoperative ROM of the knee between two groups were not significant. At one year postoperatively, the patients were assessed clinically and radiographically.

The mean postoperative KSS knee score was 96.2 points for the standard CR prosthesis group and 96.7 points for the high-flexion CR prosthesis group (p=0.464). The mean postoperative KSS function score was 83.4 points for the standard CR prosthesis group and 84.8 points for the high-flexion CR prosthesis group (p=0.446). The mean postoperative ROM was 110.8 degrees in the standard CR prosthesis group, and 114.0 degrees in high-flexion prosthesis group (p=0.236). No knee had aseptic loosening, revision, or osteolysis.

Previous report showed that “high-flexion” PS design did not increase postoperative ROM compared to standard design. However, there was no report on the postoperative ROM of “high-flexion” CR total knee prosthesis. We found no significant differences between the standard CR group and “high-flexion” CR group with regard to ROM or clinical and radiographic parameters. However, in the cases which achieved high flexion, “high-flexion” design, which chamfered posterior femoral edge, can reduce the possibility of deformation from posterior contacts under lord. Therefore, the results of the current study suggested that “high-flexion” CR design is not the design that increase ROM significantly, but might be the safe design even when the knee achieved deep flexion.

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.

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: 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.

Using in situ hybridisation and the terminal deoxynucleotidyl transferase-mediated biotin-dUTP nick end-labelling (TUNEL) reaction in rats with osteonecrosis of the femoral head we have studied the effect of ischaemia on the gene expression of the stress proteins oxygen-regulated protein 150 (ORP150) and haemoxygenase 1 (HO1) and the death mechanism of the cells involved in osteonecrosis. Both ORP150 and HO1 have been reported to have important roles in the successful adaptation to oxygen deprivation.

ORP150 and HO1 mRNA expression was induced by ischaemia in osteoblasts and osteocytes. In proliferative chondrocytes, these signals were detected constitutively. During the development of ischaemic osteonecrosis, the mechanism of cell death was apoptosis as indicated by DNA fragmentation and the presence of apoptotic bodies in osteocytes, chondrocytes and bone-marrow cells. After the initial ischaemic event, expression of ORP150 and HO1 mRNA, the TUNEL-positive reaction and empty lacunae were found sequentially. These findings were exclusive and may be considered to be markers for each stage in the development of osteonecrosis.

Six major and seven minor diagnostic criteria have been developed by the Japanese Investigation Committee for osteonecrosis of the femoral head (ONFH). We have carried out a multicentre study to clarify these.

We studied prospectively 277 hips in 222 patients, from six hospitals, who had ONFH and other hip pathology and from whom histological material was available. We identified five criteria with high specificity: 1) collapse of the femoral head without narrowing of the joint space or acetabular abnormality on radiographs, including the crescent sign; 2) demarcating sclerosis in the femoral head without narrowing or acetabular abnormality; 3) a ‘cold-in-hot’ appearance on the bone scan; 4) a low-intensity band on T1-weighted images (band pattern); and 5) evidence of trabecular and marrow necrosis on histological examination. With any combination of two of these criteria, the sensitivity and specificity of the diagnosis were 91% and 99%, respectively.

We implanted 51 Metal-Cancellous Cementless Lübeck (MCCL) prostheses into 45 patients with dysplastic hips and followed 49 hips (96.1%) for five to nine years. One had needed revision for stem fracture and one for infection; the clinical outcome of the other 47 hips was assessed using the Merle d’Aubigné and Postel hip score.

All hips were either excellent (63%) or good (37%). Three patients (6%) had mild thigh pain at six months, but this had settled within two years. Serial radiographs showed stable fixation with bone ingrowth in all hips, with increased density of the cancellous bone in contact with the implant and some trabecular ingrowth. There was early varus shift of the stem in one hip, but this stabilised in three months. Osteolysis of the femoral cortex was seen in one hip at seven years after surgery, and mild bone resorption due to stress shielding in 31 (63%). Acetabular bone grafting with autogenous bone from the femoral head gave successful support to the socket in 13 hips.

The MCCL prosthesis gave satisfactory mid-term results in patients with osteoarthritis secondary to hip dysplasia.

We have reviewed 65 bipolar arthroplasties of the hip in 55 patients with osteoarthritis secondary to dysplasia. The mean age at operation was 56 years (42 to 79) and the mean period of follow-up was 7.2 years (5.0 to 13.0).

The average Merle d’Aubigné and Postel score before operation was 10.3 and at final follow-up 15.0. There were excellent or good results in 42 hips (65%).

Migration of the outer head was observed in 50 hips (77%), most often in the group with a centre-edge angle of less than 0°, an acetabular head index of less than 60%, coverage of the outer head by the original acetabulum of less than +10° and after bone grafting of the acetabulum. This migration was progressive in 31 (62%) of the 50 hips, with massive osteolysis of the acetabulum in eight. The extent and progression of migration were closely associated with this osteolysis. Four hips required revision for extensive migration of the outer head with destruction of the acetabulum or severe acetabular osteolysis, and nine hips are awaiting revision for failure of the bipolar prosthetic head. The overall failure rate was 18%.

We report major problems after bipolar hip arthroplasty for osteoarthritis secondary to hip dysplasia with progressive migration of the outer head and massive acetabular osteolysis at five years or more after operation.