Aims. It is important to analyze objectively the hammering sound in cup press-fit technique in total hip arthroplasty (THA) in order to better understand the change of the sound during impaction. We hypothesized that a specific characteristic would present in a hammering sound with successful fixation. We designed the study to quantitatively investigate the acoustic characteristics during cementless cup impaction in THA. Methods. In 52 THAs performed between November 2018 and April 2022, the acoustic parameters of the hammering sound of 224 impacts of successful press-fit fixation, and 55 impacts of unsuccessful press-fit fixation, were analyzed. The successful fixation was defined if the following two criteria were met: 1) intraoperatively, the stability of the cup was retained after manual application of the torque test; and 2) at one month postoperatively, the cup showed no translation on radiograph. Each hammering sound was converted to sound pressures in 24 frequency bands by fast Fourier transform analysis. Basic patient characteristics were assessed as potential contributors to the hammering sound. Results. The median sound pressure (SP) of successful fixation at 0.5 to 1.0 kHz was higher than that of unsuccessful fixation (0.0694 (interquartile range (IQR) 0.04721 to 0.09576) vs 0.05425 (IQR 0.03047 to 0.06803), p < 0.001). The median SP of successful fixation at 3.5 to 4.0 kHz and 4.0 to 4.5 kHz was lower than that of unsuccessful fixation (0.0812 (IQR 0.05631 to 0.01161) vs 0.1233 (IQR 0.0730 to 0.1449), p < 0.001; and 0.0891 (IQR 0.0526 to 0.0891) vs 0.0885 (IQR 0.0716 to 0.1048); p < 0.001, respectively). There was a statistically significant positive relationship between body weight and SP at 0.5 to 1.0 kHz (p < 0.001). Multivariate analyses indicated that the SP at 0.5 to 1.0 kHz and 3.5 to 4.0 kHz was independently associated with the successful fixation. Conclusion. The frequency bands of 0.5 to 1.0 and 3.5 to 4.0 kHz were the key to distinguish the sound characteristics between successful and unsuccessful press-fit cup fixation. Cite this article: Bone Jt Open 2024;5(3):154–161

Aims. It is important to analyze objectively the hammering sound in cup press-fit technique in total hip arthroplasty (THA) in order to better understand the change of the sound during impaction. We hypothesized that a specific characteristic would present in a hammering sound with successful fixation. We designed the study to quantitatively investigate the acoustic characteristics during cementless cup impaction in THA. Methods. In 52 THAs performed between November 2018 and April 2022, the acoustic parameters of the hammering sound of 224 impacts of successful press-fit fixation, and 55 impacts of unsuccessful press-fit fixation, were analyzed. The successful fixation was defined if the following two criteria were met: 1) intraoperatively, the stability of the cup was retained after manual application of the torque test; and 2) at one month postoperatively, the cup showed no translation on radiograph. Each hammering sound was converted to sound pressures in 24 frequency bands by fast Fourier transform analysis. Basic patient characteristics were assessed as potential contributors to the hammering sound. Results. The median sound pressure (SP) of successful fixation at 0.5 to 1.0 kHz was higher than that of unsuccessful fixation (0.0694 (interquartile range (IQR) 0.04721 to 0.09576) vs 0.05425 (IQR 0.03047 to 0.06803), p < 0.001). The median SP of successful fixation at 3.5 to 4.0 kHz and 4.0 to 4.5 kHz was lower than that of unsuccessful fixation (0.0812 (IQR 0.05631 to 0.01161) vs 0.1233 (IQR 0.0730 to 0.1449), p < 0.001; and 0.0891 (IQR 0.0526 to 0.0891) vs 0.0885 (IQR 0.0716 to 0.1048); p < 0.001, respectively). There was a statistically significant positive relationship between body weight and SP at 0.5 to 1.0 kHz (p < 0.001). Multivariate analyses indicated that the SP at 0.5 to 1.0 kHz and 3.5 to 4.0 kHz was independently associated with the successful fixation. Conclusion. The frequency bands of 0.5 to 1.0 and 3.5 to 4.0 kHz were the key to distinguish the sound characteristics between successful and unsuccessful press-fit cup fixation. Cite this article: Bone Jt Open 2024;4(3):154–161

Purpose. Cementless cup with structural allograft is one of option for acetabular revision in the cases which has severe bone loss. This study was performed to verify that the structural allograft with cementless cup could be one of good options for revision of acetabular cup with severe bone defect and to verify that the allograft resorption affect the stability of cementless acetabular cup. Materials and Methods. We reviewed 25 cases of 25 patients who underwent acetabular cup rvision using cementless porous coated hemispherical cup with structural allograft from May 1992 to July 2011 July 2011. There were nine males and sixteen females with an average age of 50.0 years. The average follow-up period was 76.7(28∼212) months. The clinical evaluation was performed using Harris Hip Score(HHS) and UCLA activity score. Radiologically, the degree of resorption of grafted bone, incorporation of allograft bone with normal bone, osteolysis and cup loosening were evaluated. Results. Clinically, the average Harris hip score was improved from 54 preoperatively to 93.4 at the last follow-up. The average UCLA activity score was also improved from 4.3 preoperatively to 6.4 at the last follow-up. Radiologically, the incorporation of allograft was accomplished in 11.4 months and the resorption of grafted bone was noted in 3 cases(12%), but the allograft resorption had not progressed to moderate degree even in long term follow-up. There was no cup loosening and average survivor rate was 100% in 6 years. There was no infection, allograft nonunion, osteolysis. Conclusion. Cementless cup with structural allograft in acetabular cup reconstruction can provide excellent mi-term results in both clinical and radiological aspects. Structural allograft can provide strong mechanical support for the bone ingrowth of cementless cup. The clinical result of this study auggest that cementless cup with structural allograft can be a good option for acetabular cup revision with severe bone defect. Resorption of structural allograft rarely occurred, and the resorption of structural allograft does not affect stablility of cup even in long term follow-up

Introduction. In most cases of revision acetabular total hip arthoplasty (THA), some degree of bone loss will be accompanied. If the bone loss is massive, the management of bone defect is more challenging problem. We consider that using cementless accetabular cup for revision acetabular reconstruction is good indication when stable interface fit between the acetabular cup and bone is achieved. The purpose of this study is to review the result of revision hip arthroplasty using cementless acetabular cup with and without bone graft. Materials and methods. Between 1998 and 2012, 65 revisions using cementless acetabular cup (Mallory-Head 4 Finned component) were performed in 64 patients, whose mean age was 64.9 years. The cases of revision are aseptic loosening (53 joints), and infection (12 joints). All patients were followed up for a minimum period of 24.0 months (mean, 84 months) and were divided into two groups as follows: in group A, revisions without bone graft (28 joints); in group B, revisions with bone graft (37 joints). We compared clinical and radiographical results of group A with group B. Results. According to Paproski's classification, bone defects in Group A were evaluated as either Type I or Type IIa, and those in Group B were in the range of Type IIb to Type IIIb. Large cementless accetablar compornent with diameters of 58 mm or more were used in 6 joints and 21 cases, respectively. Postoperative radiography showed there were no significant deference of the position of hip center, lateral inclination and anteversion of acetabular cup in each group. The migration of the socket in the superior and medialaxes has not been observed in all cases at the latest follow-up. The mean JOA hip score improved from 63.1 points to 88.3 points and from 53.2 to 86.1, respectively and there were no cases of re-revisions in this series. Conclusions. Depending on the bone defect, large cementless accetablar compornent and bone graft should be considered. We are confident that results of acetabular reconstraction using cementless acetabular cup are satisfactory

We selected randomly a consecutive series of 162 patients requiring hip replacement to receive either a cementless, hemispherical, modular, titanium acetabular cup or a cemented, all-polyethylene cup. These replacements were performed by two surgeons in four general hospitals. The same surgical technique was used and a 26 mm metal-head femoral component was used in every case. After exclusions, 115 hips were studied for differences in rates of wear and osteolysis. The mean clinical follow-up was eight years and the mean radiological follow-up, 6.5 years. The cementless cups wore at a mean rate of 0.15 mm per year and the cemented cups at 0.07 mm per year. This difference was significant (p < 0.0001). Our findings in this mid-term study suggest that cementless cups wear more than cemented cups

Introduction: Stable cup anchorage in dysplastic hips is a key problem of THA. The pupose of this study was to evaluate the usefulness of a cementless cup without acetabuloplasty based on medium term Results: Method 53 patients, 47 females and 6 males aged 20 to 76 (mean 49) years at surgery were followed-up after 4.9 to 11.4 (mean 8.8) years. Crowe’s dysplasia classification showed 30 hips to be grade I, 23 grade II and 1 grade III pre-operatively. All patients were implanted with threaded pure-titanium double-cone cups. Acetabuloplasty was omitted and care was taken to achieve primary stability in the bone stock available. Pre-operative leg length discrepancy versus contralateral was 0 to 7 (mean 3.9) cm. Results: On postoperative radiography 45 cups were completely covered by bone in position I. Of 6 cups 3 quarters were covered, of 1 cup 2 thirds and of another one ½ of the cranial circumference. All of the incompletely covered cups were stable at follow-up. Altogether 51 cups had maintained their position by radiographic evidence and were firmly anchored in bone. Cup loosening in Crowe grade I and II necessitated 2 revisions. Leg length was equalized in 39 patients with mean lengthening by 3.4 (1.2 to 4.5) cm. Conclusion: In the management of dysplastic hips the system used provides stable anchorage in the bone stock without additional acetabuloplasty. Even pronounced soft tissue tension on substantial leg lengthening does not impair implant stability. Summary: Primary stable implantation of a cementless titanium cup in hip dysplastia cases without additional acetabuloplasty is achieving good medium term results

Introduction. Bulk bone grafting is commonly used in total hip arthroplasty (THA) for developmental dysplasia. However, it is a technically demanding surgery with several critical issues, including graft resorption, graft collapse, and cup loosening. The purpose of this study is to describe our new bone grafting technique and review the radiographic and clinical results. Patients and Methods. We retrospectively reviewed 105 hips in 89 patients who had undergone covered bone grafting (CBG) in total hip arthroplasty for developmental dysplasia. We excluded patients who had any previous surgeries or underwent THA with a femoral shortening osteotomy. According to the Crowe classification, 6 hips were classified as group I, 39 as group II, 40 as group III, and 20 as group IV. Follow-up was at a mean of 4.1 (1 ∼ 6.9) years. The surgery was performed using the direct anterior approach. The acetabulum was reamed as close to the original acetabulum as possible. The pressfit cementless cup was impacted into the original acetabulum. After pressfit fixation of the cup was achieved, several screws were used to reinforce the fixation. Indicating factor for using CBG was a large defect where the acetabular roof angle was more than 45 degrees and the uncovered cup was more than 2 cm (Fig.1). The superior defect of the acetabulum was packed with a sufficient amount of morselized bone using bone dust from the acetabular reamers. Then, the grafted morselized bone was covered with a bone plate from the femoral head. The bone plate was fixed with one screw to compact the morselized bone graft. The patient was allowed to walk bearing full weight immediately after surgery. We measured the height of the hip center from the teardrop line and the pelvic height on anteroposterior roentgenograms of the pelvis and calculated the ratio of the hip center to the pelvic height. We defined the anatomical hip center as the height of the center less than 15 % of the pelvic height, which was nearly equal to 30 mm, because the mean pelvic height was 210 mm. Results. The mean height of the hip center was 9.8 (4.1∼18.0) % of the pelvic height and the 101 (96.2%) cups were placed within the anatomical hip center. Radiographically, in all patients, the host-graft interface became distinct and the new cortical bone in the lateral part of the plate bone appeared within 1 year after surgery (Fig.2, 3). We observed no absorption of the plate bone graft and no migration of the cup at the last follow-up. Conclusion. CBG technique is simple, because the bone graft is always performed after the pressfit of the cup is achieved. Moreover, patients require no partial weight bearing postoperatively, because the cup is supported by the host bone with the pressfit and additional screws. The CBG technique would be an excellent option for the reconstruction of the acetabulum in patients with severe dysplasia to avoid a high hip center and bulky bone grafting

Purpose: There is no report concerning about long-term comparison result of high placed cementless cup stability with or without screws for developmental dysplasia of the hip. The aim of this study was to ascertain whether or not there are any differences in high placed cementless cup stability with or without screws at the mean 10-year (6–14) follow-up period. Method: We divided 109 hip-cases who underwent identical cementless total hip arthoplasty system (Mallory – Head : Biomet Inc.) to two groups: 57 cups with screw (screw group) and 52 cups without screw (no screw group). No case in both group underwent bulk bone graft for acetabular roof. Radiographic signs of cup instability were defined as the development of radiolucent line (> 2mm) or migration (> 4mm). Degree of subluxation by Crowe classification, cup size and cup abduction angle were also measured. Results: In both groups, there was no significant difference in terms of degree of subluxation (each grade’s %) (screw vs no screw = I (68, 73), II (21, 25), III (11,0), IV (0, 2)), age (yrs) (58, 60), cup size (mm) (46, 47) and cup abduction angle (49, 47). In screw group, one case was revised by replacing only polyethylene insert due to excessive ware. No case in both group showed any sign of component instability. Conclusion: High placed Mallory-Head type cementless cup without screws showed stable radiographic fixation as well as cup with screws at mean 10 years follow-up period

Introduction. Bulk bone grafting of the cup is commonly used in total hip arthroplasty (THA) for developmental dysplasia. However, it carries a risk of the graft collapse in the mid-term or long-term results. The purpose of this study is to describe our new bulk bone grafting technique and review the radiographic and clinical results. Patients and Methods. We retrospectively reviewed 85 hips in 74 patients who had undergone bulk bone grafting in total hip arthroplasty for developmental dysplasia between 2008 and 2013. We excluded patients who had any previous surgeries or performed THA with the femoral shortening osteotomy. According to the Crowe classification, 4 hips were classified as Type 1, 28 as Type 2, 35 as Type 3, and 18 as Type 4. Follow-up was at a mean of 4.0 years (1 to 6.1). The surgery was performed using the direct anterior approach on a standard surgical table. The acetabulum was reamed for as close to the original acetabulum as possible. The pressfit cementless cup was impacted into the original acetabulum. After the pressfit fixation of the cup was achieved, two or three screws were used to reinforce the fixation. The superior defect of the acetabulum was packed with sufficient amount of morselized bone graft. Then, the bulk bone was placed on the morselized bone graft and fixed with one screw. Post-operatively, there were no restrictions to movement or position. On the first day after surgery, the patient was allowed to walk with full weight-bearing. We measured the height of the hip center from the interteardrop line and the pelvic height on anteroposterior roentgenograms of the pelvis and calculated the ratio of the hip center to the pelvic height. We defined the anatomical hip center as the height of the center less than 15% of the pelvic height. Results. The mean height of the hip center was 10.2 (4.1∼18.0)% of the pelvic height and the 81 (95.2%) cups were placed within the anatomical hip center. We observed no collapsed grafts, no severe absorption of the grafts, and no migration of the cup at the last follow-up. Conclusion. In our technique, there is no concern of the bulk bone graft collapse even in the long-term results, because the cup is not supported by the bulk bone graft but by the host bone with the pressfit and additional screws. Moreover, 95.2% of all cups were placed within the anatomical hip center. In conclusion, our new bulk bone graft technique would be simple to perform and an excellent option for the reconstruction of the acetabulum in patients with severe dysplasia

In total hip arthroplasty (THA), cementless cup without screw holes has the putative benefits of maximizing host bone contact and reducing osteolysis by eliminating channels to backside wear particles. However, supplemental trans-acetabular screws cannot be used. 74 hips in 60 patients receiving same model of cementless cup without screw holes (Depuy Duraloc 100 HA cup) from 6/1999 to 3/2003 were prospectively followed up. All patients were allowed to have immediate full weight bearing. Age at THA was 53 ± 13 (range 24–74) years. Osteonecrosis was the leading hip disease (45% of hips). Survivorship was assessed using revision of the cup as the end point. Radiological parameters, including lateral opening angle, vertical and horizontal migration distances of the cups were measured. Paired t-test was used to compare between the measurements in early postoperative period and at final follow up. 51 hips were assessed at minimum 20 years follow-up. The mean follow-up was 22.6 (range 21 – 25) years. All the cups were well fixed. There were two cup revisions. Conventional polyethylene (PE) was used in both hips; osteolysis occurred 17 and 18 years later. Both cups were well fixed but were revised, one due to cup mal-positioning, one due to need in upsizing the articulation. 14 other hips were revised but these cups were well fixed and not revised; 9 loosened stems (most were cemented Elite plus stems), 5 PE wear and osteolysis (all were conventional PE). At 20 years, the survivorship of cups was 96.1%. Changes in lateral opening angle, vertical and horizontal migration distances were 0.44±1.59°, 0.01±1.52mm and -0.32±1.47mm respectively, without statistical significance. This study provided evidence of excellent long-term survivorship of cementless cup without screw holes. Immediate postoperative weight-bearing also did not lead to cup migration in the long-term

The concept of stainless steel dual mobility cups in total hip arthroplasty has demonstrated very low long-term instability rates and a 98% survival rate after 12 years. We systematically implanted titanium alloy acetabular cups during a one year period. The purpose of our retrospective study was to report the 18-year clinical outcome data in a homogeneous and continuous series of 103 primary total hip replacements after implantation of a cementless titanium cup. All patients were implanted with NOVAE Ti (SERF) cups made of titanium alloy combined with a retentive polyethylene liner and a 22.2 mm cobalt chrome prosthetic head. Mean patient age at the time of surgery was 53 years. All patients were clinically and radiographically evaluated. The overall 18-year actuarial cup survival rate with a 95% confidence interval was 87.4%. At last follow-up, there was no evidence of implant instability whereas acetabular aseptic loosening was reported in one case and high wear of the retentive liner in 9. The results of this investigation confirmed the long-term stability of dual-mobility implants. The main limitation of this system was early wear of the polyethylene liner in contact with the titanium metal back and reaction with third body along with loss of liner retentivity. In our study, titanium demonstrated favourable osteointegration properties but poor tribologic characteristics, therefore suggesting its interest at the bone-cup interface only

The aim of this paper is to present a new solution in treating osteoarthritis after congenital dysplasia. In the First Orthopaedic Clinic in Prague, we have obtained, by using oval-shaped cups, excellent results in the treatment of acetabular deficiency occurring in THA loosening. These positive results have also encouraged us to use the implants in THA for secondary coxarthrosis.

In severe acetabular defects, an endoprothesis is very difficult to implant. A whole range of methods has been described for fixing the acetabular component. We prefer not to use cemented implants with middle-aged patients. Methods using bulk bone grafts are being scaled down. Cup implantation to the neoacetabulum is disadvantageous because forces inherent to the hip joint are considerably higher in the superior lateral position. Cotyloplasty and controlled fracture impair the medial wall with the enhanced risk of implant protrusion to the pelvis. The implementation of an oval cup eliminates the above-mentioned disadvantages.

During the period of 1994 to 1998, we applied the LOR cup in treating secondary coxarthrosis eight times in six women (mean age: 54 years). 83% had already been operated for congenital hip dislocation. The stage of the dysplasia was classified as Crowe II in two hip joints, Crowe III in four, and Crowe IV in two. An average of four screws were used for a 52x64 cup. Mean follow-up was 4.8 years.

The mean Harris hip score at follow-up was 92 points. There were no infections, luxations, implant migrations, or screw failures. The radiograph evaluations revealed just one case of a translucent line 1 mm wide in the b,c zone. Osteointegration was perfect with the other implants.

Using the oval-shaped cup does not usually require implementation of bulk bone grafts. Implant shape and the option of implementing an eccentric inlay enables preservation of the rotational centre, which is advantageous in terms of biomechanics. Implantation of the cup is easy and fast. Because of the good results, we suggest introducing the oval-shaped cup as a standard method of THA primo-implantation with patients who have acetabular dysplasia. The LOR cup was designed as a revision implant, but a disadvantage is the insufficient size scale and the 32 insert. For widespread application, it is therefore necessary to design a smaller size 28 inlay cup. We are currently developing our own acetabular component with a more suitable size scale and a plasma-sprayed hydroxyapatite ceramic coating.

Introduction

The mid- or long-term results of acetabular revision total hip arthroplasty (THA) in Korea are rare. The purpose of this study is to report the mid-term radiographic results (> 5 years) of acetabular revision THA with porous-coated cementless Trilogy^® cup (Zimmer, Warsaw, IN, USA).

Introduction: Cementless press-fit cups are the most widely used acetabular implants in total hip arthroplasty today. Their primary and secondary stability is largely determined by the design and choice of surface coating. Porous titanium coatings are used for the majority of cementless acetabular implants. However, an additional hydroxyapatite (HA) layer has been advocated for superior bone ongrowth. We studied the effect of additional HA coating on early micromotion of a porous titanium plasmasprayed cup with a flattened pole. A secondary objective was to compare the extent of micromotion of this well established cementless cup to data of other press-fit cups. Methods: A total of 44 female patients (45 hips) undergoing total hip arthroplasty for osteoarthritis consented to participate in this prospective, IRB approved study. They were randomized for either a press-fit cup (EP-FIT PLUS. ®. , Plus Orthopedics AG, Switzerland) with a titanium plasma sprayed surface (Ti-group) or with additional HA coating (HA -group). All cups were used with the same combination of stem, PE liner and ceramic head. Model-based radiostereometry (MBRSA) was used to measure translation and rotation immediately postoperative, at 6 weeks, 3, 6, and 12 months. Statistical analysis of migration was performed utilizing one-sided Mann-Whitney tests and ANOVA. Results: At one year, mean translation in the HA-group (Ti-group) along the medial-lateral (x), proximal-distal (y) and anterior-posterior (z) axes was −0.01 (0.07), 0.08 (0.09), and 0.03 (−0.06) mm, respectively. Mean rotation around the x-axis (anterior-posterior tilt) was −0.19 (−0.16), the y-axis (anteversion-retroversion) was −0.10 (−0.19), and the zaxis (adduction-abduction) was 0.23 (−0.05) degrees. Our hypothesis that translation and rotation would be different in the two groups was rejected (p< 0.00) for all dimensions except for rotation about the z-axis (p=0.10). The was no evidence for different migration patterns throughout the examined time points. All patients had excellent clinical outcome with a mean Harris Hip Score of 95.4 (HA-group) and 95.3 (Ti-group) (p=0.10). Plain radiographs of the cups showed good osseointegration. Discussion: With excellent primary stability in both the Ti-group and the HA-group, we conclude, that HA-coating does not significantly increase stability of this flattened pole press-fit cup during the first postoperative year. We were able to show that the early stability of this cup is well comparable to that of the more frequently used hemispherical cups with initial stability being one prerequisite for long-term success. RSA measurements after 2 years will be conducted to confirm the current findings and the cup is also being studied in a long-term observation

In acetabular revision press-fit cups usually are used in smaller defects and contact to the host bone should be more than 50 %. Due to the thin wall thickness and the surface design the cementless press-fit cup Allofit S has a specific characteristic during implantation. Therefore this cup was used for revision with greater acetabular defects and analysed in a prospective study. The press-fit in these cases was 4 mm and additional 2 or 3 screws into the Os ilium were used. 64 cups were were followed prospectively for 38.3 months with a minimum of 24 months and examined clinically (Harris-Hip-Score) and radiographically for migration (Method of Nunn et al.) and loosening (Method of Delee and Charnley). Corresponding to Nunn et al. and Blum et al., cup migration was defined to be a change of position greater than 3 mm or referring to Cordero-Ampuero et al. and Dickob et al. a change of inclination greater than 5 degrees. There were 25 revisions of the cup and 39 complete exchanges of the prosthesis due to 54 aseptic and 10 septic loosenings (two-step revision with spacer and cementless reimplantation). There were acetabular defects of type Paprosky 2A in 12 cases, of type 2B in 15 cases, type 2C in 19 cases, type 3A in 16 cases and type 3 B in 2 cases. The average age of the patients was 70.9 ± 8.9 years. The Harris-Hip-Score increased from 45.4 ± 14.9 points preoperatively to 81.8 ± 17.5 points one year and 82.3 ± 17.1 points two years postoperative. There was no loosing or significant migration of the cups. The Allofit S press-fit cup shows good result in cup revisions with greater acetabular defects when using a press-fit of 4 mm and additional 2 or 3 screws. In these cases it seems to be a good and cheeper alternative to specific implants like trabecular metal cups

Introduction: The Allofit cup is a hemispherical pressfit cup with a flattened pole for cementless implantation. Clinical use started in 1993 and we report our clinical and radiographic results of the first 100 cases. 75 hips of this group have been followed during the first 3 to 4 years using EBRA for migration analysis. These results also are presented.

Material: Out of 100 hips 81 have been followed mith a mean of 10,1 years (9,8–11). 6 patients died, 11 did not show for follow up an 1 patient had a revision for deep infection with two-stage exchange meanwhile.

The initial diagnosis was primary coxarthrosis in 63, rheumatoid arthritis in 10, congenital dislocation of the hip in 5 and necrosis of the femoral hed in 3.

In all cases the cementless Alloclassic stem was used, as bearing material metasul was implanted in 73 and ceramic-polyethylene in 8 cases.

Complications: For prolonged exsudation from the wound one soft tissue revision was necessary. 2 luxations were treated conservative. One early deep infection healed after synovectomy and irrigation, one late deep infection was cured by a two stage reimplantation.

Results: The EBRA migration analysis after 3,6 years (2,3–4,2) showed cranial migration of 0,35 mm (0,2–0,6 mm), medial migration of 0,25 mm (0,10–0,40 mm) and a calculated total migration as a combination of both of 0,45 mm (0,22–0,72). Therefore at this time there was no evidence of early loosening or migration indicating later loosening.

The preoperative Harris hip score was 53,13 pts (23–73), the postoperative score after 10 years 96,5 (78–100).

Radiographic evaluation after 10 years showed no lucencies in 78 of 81 jpints. 3 hips had a lucent line of 1mm in zone III. We detected no signs of osteolysis, loosening or migration.

No reoperations for any reason exept 2 septic cases have been performed yet.

Summary: After 10 years the clinical and radiological results of this implant are very satisfying. These results confirm the early observations of a migration analysis performed 6 to 8 years before.

First generation uncemented modular cups reproduciblyfixed to bone but they were associated with unacceptable rates of pelvicosteolysis and mechanical failure. Consequently, second generation cups weredeveloped with shells having a limited number of holes or no holes, and improved conformity and locking mechanisms with the liner. The purpose of this study is to report the clinical and radiographic results of a second generation acetabular component for primary total hip arthroplasty.

297 patients who underwent 335 consecutive primary total hip arthroplasties by a single surgeon with the Trilogy modular acetabular component were followed clinically with the Hospital for Special Surgery Hip Scoring System and radiographs, for 4 to 7 years. All cups were implanted with a press-fit technique.

This second generation acetabular cup design achieved predictable fixation and was associated with a low prevalence of revision for loosening and low prevalence of osteolysis at an intermediate follow up.

Aim: The purpose of this study was to assess the results with use of an oval cementless acetabular component for revision total hip arthroplasty. Methods: 30 hips had an acetabular revision with an cementless oval acetabular component. No patient was lost to follow-up, but one died during the study period. All defects were classiþed during surgery according the AAOS classiþcation. All patients were evaluated radiographically and clinically and were followed for an average of thirty-six months (range, twenty four to fourty eight months). In 21 of the 30 hips no additional bone grafting was necessary. Results: There were 17 segmental defects (type 1), 12 combined defects (type III) and one case of pelvic discontinuity (type IV). At the time of follow-up, 27 (93.1%) of 29 cups were stable. One of the loosening affected the patient with pelvic discontinuity, the other a patient with a combined segmental defect including the medial wall. The average Harris Hip Score improved from 39 points (range: 15–73 points) preoperatively to 89 points (range 68–96 points) postoperatively. Complications included three dislocations without recurrency. The radiological follow-up examinations revealed good osteointegration of 27 implants. All postoperatively remaining defects were completly þlled in by bone at the follow up. Conclusion: The asymmetrical shape of the BOFOR enhanced the primary stabilty on the lateral columns with three point anchorage. We recommend this device when a patient has an oblong-shaped acetabular defect and the surgeon wants to correct an elevated hip center. However, the medial wall of the acetabulum (Kohlerñs line) should be intact.

Aims. Manual impaction, with a mallet and introducer, remains the standard method of installing cementless acetabular cups during total hip arthroplasty (THA). This study aims to quantify the accuracy and precision of manual impaction strikes during the seating of an acetabular component. This understanding aims to help improve impaction surgical techniques and inform the development of future technologies. Methods. Posterior approach THAs were carried out on three cadavers by an expert orthopaedic surgeon. An instrumented mallet and introducer were used to insert cementless acetabular cups. The motion of the mallet, relative to the introducer, was analyzed for a total of 110 strikes split into low-, medium-, and high-effort strikes. Three parameters were extracted from these data: strike vector, strike offset, and mallet face alignment. Results. The force vector of the mallet strike, relative to the introducer axis, was misaligned by an average of 18.1°, resulting in an average wasted strike energy of 6.1%. Furthermore, the mean strike offset was 19.8 mm from the centre of the introducer axis and the mallet face, relative to the introducer strike face, was misaligned by a mean angle of 15.2° from the introducer strike face. Conclusion. The direction of the impact vector in manual impaction lacks both accuracy and precision. There is an opportunity to improve this through more advanced impaction instruments or surgical training. Cite this article: Bone Joint Res 2024;13(4):193–200