Objectives. The paradoxical migration of the femoral neck element (FNE) superomedially against gravity, with respect to the intramedullary component of the cephalomedullary device, is a poorly understood phenomenon increasingly seen in the management of pertrochanteric hip fractures with the intramedullary nail. The aim of this study was to investigate the role of bidirectional loading on the medial migration phenomenon, based on unique wear patterns seen on scanning electron microscopy of retrieved implants suggestive of FNE toggling. Methods. A total of 18 synthetic femurs (Sawbones, Vashon Island, Washington) with comminuted pertrochanteric fractures were divided into three groups (n = 6 per group). Fracture fixation was performed using the Proximal Femoral Nail Antirotation (PFNA) implant (Synthes, Oberdorf, Switzerland; n = 6). Group 1 was subjected to unidirectional compression loading (600 N), with an elastomer (70A durometer) replacing loose fracture fragments to simulate surrounding soft-tissue tensioning. Group 2 was subjected to bidirectional loading (600 N compression loading, 120 N tensile loading), also with the elastomer replacing loose fracture fragments. Group 3 was subjected to bidirectional loading (600 N compression loading, 120 N tensile loading) without the elastomer. All constructs were tested at 2 Hz for 5000 cycles or until cut-out occurred. The medial migration distance (MMD) was recorded at the end of the testing cycles. Results. The MMDs for Groups 1, 2, and 3 were 1.02 mm, 6.27 mm, and 5.44 mm respectively, with reliable reproduction of medial migration seen in all groups. Bidirectional loading groups showed significantly higher MMDs compared with the unidirectional loading group (p < 0.01). Conclusion. Our results demonstrate significant contributions of bidirectional cyclic loading to the medial migration phenomenon in cephalomedullary nail fixation of pertrochanteric hip fractures. Cite this article: G. W. Law, Y. R. Wong, A. K-S. Yew, A. C. T. Choh, J. S. B. Koh, T. S. Howe. Medial migration in cephalomedullary nail fixation of pertrochanteric hip fractures: A biomechanical analysis using a novel bidirectional cyclic loading model. Bone Joint Res 2019;8:313–322. DOI: 10.1302/2046-3758.87.BJR-2018-0271.R1

After many patients, some of whom were unexpectedly young, had presented with medial migration of the hemi-prosthetic head and erosion of the glenoid, we decided 2 years ago to do preoperative DEXA on all shoulder replacement patients. The aim was first to determine normal bone mineral density (BMD) of the glenoid and secondly to predict which patients would be at risk. We used the same DEXA method as for the hip. The glenoid was divided into three areas, numbered R1, R2 and R3, and we determined BMD in each of them. Preliminary studies showed that patients fell into two groups. In one, BMD in the R2 and R3 areas was in the range 0.3 to 0.5. Most often the patients in this group were younger or had acute trauma and the contralateral shoulder was not pathological. BMD in the other group was in the range 0.9 to 1.3. Nearly all patients with OA of the shoulder fell into this group. In this ongoing study, patients are followed up annually with clinical examination and standard radiographs. Follow-up to date has only been 2 years. So far no medial migration of the hemi-prosthetic head has been noted in patients in the group with BMD between 0.9 to 1.3

Introduction and Objectives: Acetabular bone defects in hip replacement therapy present difficulties in terms of achieving stable, long-lasting fixation of the implant. Various surgical techniques exist to correct this problem. In this study we analysed the clinical and radiographic progression of a series of patients treated with fragmented grafts using the X-Change acetabular revision method. Materials and Methods: From November 1988 to February 1998, 24 patients were treated, with an average age of 64.5 (±7) at the time of surgery. Patients were evaluated clinically preoperatively and were evaluated using the Harris scale at the end of the follow-up period. Defects were classified according to Paprosky’s classification of acetabular bone defects. Radiographic studies were used to evaluate upward and medial migration of the acetabular component and to look for signs of loosening. Follow-up time was a minimum of 12 months, with an average of 56.2 months. Results: Average score on the Harris scale went from 49.7 points (±12.9) preoperatively to 88.2 points (±14.1) on follow-up. There was no graft incorporation in 5 patients (20%). There were 3 infections, 2 prosthetic dislocations, and one case of pulmonary thromboembolism. Upward migration of the cup (from the upper obturator line) was 0.48 cm (±0.72) postoperatively and 0.48 cm (±0.84) at follow-up. Medial migration (measured from Kohler’s line) was −0.16 cm (±0.50) postoperatively and −0.09 cm (±0.56) on follow-up. Cup angle (measured at the anteroposterior plate of the pelvis) changed from 48.9° (±5°) to 56° (±7°) at the conclusion of the follow-up period. Discussion and Conclusions: This reconstructive technique provides stable, long-lasting fixation of the implant with complication rates similar to those described in the literature. We consider it a useful technique in the management of this type of defect, particularly in young patients who need to recover acetabular bone stock

Aims

This cross-sectional study aimed to investigate the in vivo ankle kinetic alterations in patients with concomitant chronic ankle instability (CAI) and osteochondral lesion of the talus (OLT), which may offer opportunities for clinician intervention in treatment and rehabilitation.

Introduction. Although femoral neck fractures remain a concern in short term failures for hip resurfacing, acetabular component position and fixation are increasingly being recognized as causes of mid term failures for hip resurfacing. This study aimed to evaluate the migration pattern of a cobalt chrome, beaded acetabular component for a metal on metal hip resurfacing. Methods. 130 patients underwent metal on metal hip resurfacing: 66 hips in 60 patients had sufficient films to be included in this analysis. Forty-eight patients were male and 12 were female, with a mean age of 50 (range, 32–66). Ninety-five percent of the procedures were performed for osteoarthritis. In all cases acetabular migration was measured both vertically and horizontally, on serial radiographs using the computer-assisted Ein Bild Röntgen Analyse method. A minimum of three comparable radiographs is necessary for calculating the migration curves. We scored medial migration as negative horizontal movement. Results. At a mean follow up 25.3 months (24–36 months), each hip had an average of 5.1 radiographs for analysis. 12.5% of the cups showed more than 1 mm migration in the medial-lateral axis and 45.3% more than 1 mm in the vertical axis. 23% of the cups showed a combined migration of greater than 2 mm in the observation period. Two of these cases required revision for aseptic loosening at 34 months. Discussion and Conclusion. Previous studies have shown EBRA to have an excellent sensitivity and positive predictive value for mid to long term cup failure. This data raises concern about the initial stability if this acetabular component. Continued follow-up is needed to monitor the longer term survival of this implant

Introduction. The standard practice of uncomplicated total ankle replacement (TAR) involves postoperative immobilisation. Periprosthetic fracture is a well-recognised complication following ankle arthroplasty. It occurs predominantly as a stress reaction on the medial tibial metaphysis during the postoperative rehabilitation period. Occasionally it occurs during surgery. We present fractures from a single-centre series of Mobility TARs. Materials and Methods. We have 133 TARs with 3 to 48 months' follow-up. 28 patients were excluded for the following reasons: other major procedure performed concurrently (osteotomy or tendon transfer), custom prosthesis, revision surgery, fusion conversions, or patients involved in a separate RCT (n = 16). We do not routinely immobilise patients postoperatively but allow partial to full weight-bearing as able. Outcome scores were compared to those without fractures. Results. 105 patients were included in the study. Nine (8.6%) patients sustained a periprosthetic fracture with no history of significant trauma. One of these was intraoperative; this was a posterior tibial fracture noticed on postoperative radiographs. The remainder (n = 8) were tibial metaphyseal stress fractures, all occurring within the first three months, most (n = 6) within six weeks. One occurred on the sixth post-op day and was managed in cast. Seven were asymptomatic at diagnosis and managed nonoperatively; one was fixed at three months due to radiological medial migration of the talus and one was fixed at seven months due to progression to symptomatic non-union. The remainder united. Between those with and without fractures, there was no significant difference in age (mean 61.4 vs. 62.1, p = 0.387), diagnosis leading to arthroplasty (OA, RA, PTOA), or outcome scores (12 months: 83 vs. 78, p = 0.237). Conclusion. Periprosthetic fracture remains a significant complication of total ankle arthroplasty. However, in our series, they do not lead to increased morbidity or worse outcome scores than patients without fractures and most can be managed nonoperatively

Introduction. The standard practice of uncomplicated total ankle replacement (TAR) involves post-operative immobilisation. Periprosthetic fracture is a well-recognised complication following ankle arthroplasty. It occurs predominantly as a stress reaction on the medial tibial metaphysis during the post-operative rehabilitation period. Occasionally it occurs during surgery. We present fractures from a single-centre series of Mobility TARs. Materials and Methods. We have 133 TARs with 3 to 48 months' follow-up. 28 patients were excluded for the following reasons: other major procedure performed concurrently (osteotomy or tendon transfer), custom prosthesis, revision surgery, fusion conversions, or patients involved in a separate RCT (n = 16). We do not routinely immobilise patients post-operatively but allow partial to full weight-bearing as able. Outcome scores were compared to those without fractures. Results. 105 patients were included in the study. Nine (8.6%) patients sustained a periprosthetic fracture with no history of significant trauma. One of these was intra-operative; this was a posterior tibial fracture noticed on post-operative radiographs. The remainder (n = 8) were tibial metaphyseal stress fractures, all occurring within the first three months, most (n = 6) within six weeks. One occurred on the sixth post-op day and was managed in cast. Seven were asymptomatic at diagnosis and managed non-operatively; one was fixed at three months due to radiological medial migration of the talus and one was fixed at seven months due to progression to symptomatic non-union. The remainder united. Between those with and without fractures, there was no significant difference in age (mean 61.4 vs. 62.1, p = 0.387), diagnosis leading to arthroplasty (OA, RA, PTOA), or outcome scores (12 months: 83 vs. 78, p = 0.237). Conclusion. Periprosthetic fracture remains a significant complication of total ankle arthroplasty. However, in our series, they do not lead to increased morbidity or worse outcome scores than patients without fractures and most can be managed non-operatively

Recognized anatomic variations that lead to patella instability include patella alta and trochlea dysplasia. Lateralization of the extensor mechanism relative to the trochlea is often considered to be a contributing factor; however, controversy remains as to the degree this contributes to instability and how this should be measured. As the tibial tuberosity-trochlear groove (TT-TG) is one of most common imaging measurements to assess lateralization of the extensor mechanism, it is important to understand its strengths and weaknesses. Care needs to be taken while interpreting the TT-TG value as it is affected by many factors. Medializing tibial tubercle osteotomy is sometimes used to correct the TT-TG, but may not truly address the underlying anatomical problem. This review set out to determine whether the TT-TG distance sufficiently summarizes the pathoanatomy, and if this assists with planning of surgery in patellar instability.

Cite this article: Bone Jt Open 2022;3(3):268–274.

CLS Spotorno cotyle consists of an expansible hemispheric external component with troncoconic internal thin thread of Protasul Titanium. It also has a polyethylene UHMW internal threaded element which adapts prosthesic femoral heads (28–32 mm of diameter). The implant procedure is technically simple. First of all, the acetabulum is prepared by milling the cartilaginous surface with hemispheric mills. The external element is inserted pressthorn;t, later it is expanded with a troncoconic thread, the high density polyethylene is threaded inside the expanded component. The aim of this comunication is to expose the clinical and radiological outcome of 50 patients whom a CLS Spotorno expansible cotyle were implanted with a mean clinical follow up of 14 years. The indications are exposed considering the age, cotyle morphology and bone quality. The evaluation included both clinical and radiographic parameter. Test of Postel and Merle DñAubigne were assessed for this clinical outcome. Radiological evaluation included: Acetabular angle desviation, periprosthesic osteolysis, proximal and medial migration of the cotyle and polyethylene wear. The primary stability of the acetabular stems were found excellent. Good osteointegration and biocompatibility were demostrated by serial radiographic and funtional scores. We also present the surgical procedure, the complications and the conclusions of the study

Introduction: Impaction allografting is an established method for restoring deficient bone during revision arthroplasty of the hip. Graft augmentation with synthetic materials has been proposed and evaluated experimentally. Our aim was to assess clinically whether migration and wear of implants with a synthetic graft mix would be equivalent to pure allograft. Materials and Methods: Patient inclusion criteria were: acetabular and or femoral defects from aseptically loosened primary THR undergoing cemented revision with impaction grafting; age 55–80 years; initial diagnosis of osteo arthritis; good health with reasonable daily activity level. Patients were randomized to receive either pure allograft or a 50% mixture with a porous hydroxyapatite material (Apapore60, Apatech, UK). Revision was with the Exeter stem, antibiotic Simplex cement (Stryker Howmedica Ltd), and Ogee cup (Depuy Int. Ltd., Leeds, UK). Tantalum markers were inserted into the pelvis, cup, femur, cement and graft in order to measure migration with radiostereometry (RSA). Patients received a sequence of RSA examinations up to 2 years. A total of 26 patients (18 for the femur) have been analysed. Results: At 2 years no significant differences were seen in cup wear, or migration of the cup, femoral and pelvic graft markers. Stem migration occurred mainly at the stem cement interface. The rate of distal migration for the femoral head was greater for pure allograft in the first year (p < 0.05), however this rate reduced significantly in year two. Higher medial migration in year one was observed for the proximal medial cement mantle for allograft (p < 0.05). Conclusions: Improved stability and normal cup wear were observed in a randomized clinical study for a synthetically augmented allograft. This agrees with experimental findings. 1. Longer follow up with increased patient numbers is recommended to confirm these findings

Purpose: Although femoral neck fractures remain a concern in terms of short term failures for hip resurfacing, acetabular component position and fixation are increasingly being recognized as causes of mid term failures for hip resurfacing. The purpose of our study was to evaluate the migration pattern of a cementless acetabular component for a metal on metal hip resurfacing. Method: Between January 2006 and June 2007, 130 patients underwent metal on metal hip resurfacing; 66 hips in 60 patients were included in this analysis. Forty-eight patients were male and 12 were female, with a mean age of 50 (range, 32–66). Ninety-five percent of the surgeries were performed for osteoarthritis. All surgeries were performed by two surgeons using the Conserve Plus (Wright Medical Technology, Memphis, TN) hip resurfacing system. The acetabular component is a monoblock cobalt chrome with a porous beaded surface for osteointegration. In all cases acetabular migration was measured both vertically and horizontally, on serial radiographs using the computer-assisted Ein Bild Röntgen Analyse (EBRA) method. A minimum of three comparable radiographs is necessary for calculating the migration curves. We scored medial migration as negative horizontal movement. Results: At a mean follow up 25.3 months (range, 24–36 months), each hip had an average of 5.1 radiographs for analysis. The software excluded two cases for poor comparability ending finally with 64 cases for the analysis. Eighty-seven point five per cent of the cups showed less than 1 mm migration in the medium-lateral axis and 54.7% less than 1 mm in the vertical axis. Seventy-seven percent of the cups showed a combined migration of less than 2 mm in the observation period, without radiolucencies, leaving 23% of the acetabular components with 2 mm or greater of component migration. One of these cases required revision for aseptic loosening at 34 months. Conclusion: In our study the majority of the acetabular components were stable with some of the migration observed secondary to lack of complete initial seating due to the rigidity of the shell. Krismer et al did report on the migration of the PCA shell (also a porous beaded cobalt-chrome shell) using EBRA, with 27.5% of the shells demonstrating > 1 mm of migration. Although hip resurfacing has only mid term followup, results have been good to excellent. Caution should still be maintained since the higher frictional torque generated by the larger femoral head size as well as the nanometer size particles could negatively affect long term fixation of the acetabular component

Introduction: Some reports have suggested an unacceptable failure rate of Elite Plus stem in the medium term. We have previously argued that other measurements must be made in addition to RSA in order to assess reasons for abnormal migrations. This 3-year RSA study of Elite Plus stems assessed the migration pattern and factors that influenced it. Method: Twenty five patients (23 OA, 2 RA, mean age 60.4 years (37–81)) underwent Elite Plus THR (single surgeon). A-P radiographs were assessed for cementing technique, and measurements (canal widths, stem orientation, cement thickness etc) were taken using CAD software. Activity score and BMI were also recorded. Multiple factors were assessed for correlation with the main components of migration. Results: One patient’s stem centroid migrated proximally (due to valgus rotation about the shoulder) and the mean subsidence of the others was 0.297 mm at 36 months. Mean internal rotation and posterior head migration (25 patients) at that time were: 1.42° (CI: 0.99° to 1.86°) and 0.801 mm (CI: 0.526 mm to 1.076 mm), neither being significantly different from migrations at 24 months. One patient’s stem migrated continuously. By 36 months, it had subsided 1.279 mm and internally rotated 4.2°. Some significant correlations (p < 0.05, rho > 0.6) were 3M and 36M subsidence with proximal-medial cement thickness; effective offset with 36M medial migration. Discussion: The one patient with continuous high migration had the highest activity level. This was corroborated by a wear measurement of 3.5 mm in the contralateral (Charnley) hip which had been in place for 9 years (assuming the head was not scratched). If RSA, 3 years postoperatively, can predict future outcome, the 4% failure rate is similar to the ten year results of the Charnley hip

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

Purpose: To assess the clinical and radiological performance of the Ultima THR. Material-Methods: Between January 1991 and July 1994, 147 consecutive patients (154 hips) underwent a primary THR using an all-polyethylene cemented cup and the Ultima Ti alloy smooth, collarless, double tapered, straight stem. 65% were females and primary diagnosis was OA or RA in the majority. The average age at operation was 66.4 years. At average follow-up of 76 months, 34 patients (35 hips) were dead and 5 were lost. Patients were annually assessed clinically (HSS) and radiologically. Radiographs were digitized and migration analysis and cup wear was performed using the EBRA method. Results: There were 9 aseptic failures (5 stems, 1 cup and 3 both components). Cup migration analysis was possible in 106 cases. Migration was detected in 62 of them (18 proximal, 15 medial, and 29 combined). Proximal migration ranged from 0.8 mm-4.0 mm and medial migration from 1.0 mm–3.5 mm. The average cumulative linear cup wear was 0.2 mm. Stem migration analysis was possible in 114 cases. At 2 years, 35 stems subsided less than 1.5 mm. Migration of more than 1.5 mm was observed in 16 stems. Early subsidence of more than 1.5 mm was highly predictive for later revision. Conclusions: Ti-stems have been criticised for high failure rate but the exact mechanism of loosening is multifactorial. Our revision rate and the low incidence of focal osteolysis, even in the presence of a small degree of stem subsidence, indicate that a smooth double tapered Ti-alloy cemented stem may offer a durable long-term solution

Positioning and secure fixation of the acetabular component without bone cement in dysplastic and deficient acetabulum is technically challenging because of the distorted anatomy of the acetabulum such as shallow and very thin medial and anterior wall, deficient super-olateral dome. Several treatment options have been reported to solve these problems when total hip arthroplasty is needed. The author developed a new technique of circumferential acetabular medial wall displacement osteotomy to get secure fixation of the cementless hemispherical acetabular component at the site of the original acetabulum. This technique preserves the thin medial wall, deepens, and enlarges the acetabulum without additional structural bone graft. The procedure can also provide appropriate positioning and sufficient coverage of the acetabular cup. From October 1989 to October 1995, we analyzed 84 hips in 80 patients who had a cementless total hip replacement with circumferential acetabular medial wall osteotomy at the Kyung Hee University Hospital. There were 28 male and 52 female patients with an average age of 49 years (range 25–71). Initial diagnoses were congenital dislocation, severe dysplasia, infection sequelae, and secondary osteoarthritis. The follow-up period ranged from 5 years to 11 years, the average being 7.2 years. All acetabular components used in this procedure were cementless porous coated hemispherical Harris-Galante (HG) I or II cup. The acetabular cup had secure fixation at the site of the original acetabulum without bone cement in all cases. Cup coverage ratio has become 97.7% in average. There was no radiolucent line around the cup or loosening. None of the acetabular cups with circumferential acetabular medial wall osteotomy had signs of medial migration. Bone union at the site of osteotomy was achieved in all cases. Bony ingrowth into the porous surface and remodeling around osteotomized acetabular medial wall was excellent. Technical pitfalls and advantages in biomechanical viewpoint of the procedure will be discussed

Introduction: This study investigates the influence of surgical approach on the early migration of a cemented Total Hip Replacement (THR), assessed by Roentgen Stereo-photogrammetric Analysis (RSA). Rapid early migration has been correlated with premature implant failure. Method: 46 patients awaiting THR were allocated into Posterior Approach (PA) and Lateral Approach (LA) groups. RSA was used to assess post-operative stem position and migration at 1 year. Post-operative gait was examined for a subgroup of patients. Results: There was no difference in initial stem position within the medulla. Significant differences in distal migration were found; (LA 0.78±0.07mm and PA 1.27±0.15mm), p< 0.01. Posterior head migration for the PA group (0.78±0.18mm) was twice that for the LA group (0.46±0.08mm), p< 0.05. The PA group showed greater medial migration of the prosthesis tip (0.62±0.24mm), compared to the LA group (0.11±0.08mm), p< 0.05. During gait, the legs of the PA group were relatively internally rotated when compared to those of the LA group. Discussion: The PA implants rotate internally and into valgus further than the LA implants. The starting positions of the prostheses were the same with similar cement and prostheses characteristics. We can infer that surgical approach and therefore muscle function have a significant effect upon component migration. During gait, the PA group has relatively internally rotated legs, probably due to short external rotator weakness. Hence, the internally rotating torque on the femoral stem will be larger, explaining the rapid migration in this direction. With the LA approach, the abductors are likely to be damaged. Therefore, the PA joint reaction force will be more laterally directed, explaining the higher coronal plane rotation rates seen in this group. Conclusion: Profound differences exist in early migration, between the LA and PA. Different muscle function may account for this and probably influences long-term outcome

Aim: The purpose of this work is to report the early results from medial protrusio technique for placement of acetabular component without cement in patients who have acetabular dysplasia. Material and Method: Thirty-two hip replacements were performed in thirty consecutive cases with dysplastic osteoarthritis between 2001 and 2003. In none of the patients an augmentation with bone or cement of the superolateral aspect of the acetabulum was made. Indication for operation was a painful hip joint that could not be alleviated by conservative treatment. According to Crowe’s criteria the dysplasia was evaluated as type I (19); type II (11); type III (3). The size and localization of the true acetabulum were evaluated using Ranawat’s triangle on a weigh-bearing preoperative X-ray. Clinical appraisal of the joint was done preoperatively, at the sixth, twelfth and thirty-six month postoperatively by the scheme of Merle dAubigne and Postel modified by Charnley. In 29 cases the surgery was performed via lateral transgluteal approach of Hardinge-Mulliken and in the rest of the cases through anterolateral approach of Watson-Jones. In all cases the medial wall was perforated with reaming and the medial periosteum was torn to visualize the illiacus muscle. Results: One to three-year postoperatively clinical results showed significant improvement: in 28 joints 15–18 points (excellent and very good results); in 5 joints 14–16 points (good result). The medialization of the acetabular component is found to be 5.72.8 mm average values. X-ray evidences for medial migration of the acetabular component and early loosening were not found. Nerve palsy and intraoperative fracture of the femur did not occur, but one joint dislocated 24 days after the replacement despite the resection of anterior inferior iliac spine. Excessive medialization and impingement of the femur to the pelvic bone were the reasons for this complication. Conclusion: When precisely planned the medial protrusion technique without cement fixation of the acetabu-lar component is a good alternative for arthroplasty in dysplastic hip joint. Particular attention must be paid in preserving enough thickness of the anterior and posterior acetabular walls during the reaming process. The perforation of the medial wall must not exceed 25–30% from the surface, because of plain risk of protrusion of the component beyond the teardrop figure of Kohler

Introduction: The objectives of this study were to evaluate acetabular bone deficiency in revision THA with a simple classification on the anteroposterior pelvis radiograph and correlate the results of cementless hemispherical porous coated cup and cancellous bone graft reconstruction. Methods: 70 acetabular revisions reconstructed employing large ‘jumbo’ porous coated cups with cancellous allo-grafting were evaluated at a mean follow-up of 5 years (range 2 – 10 years). During this time period 7 additional acetabular reconstructions required impaction grafting, cage reinforcement and cemented cups. Pre- and postoperative measurements of acetabular bone loss and the position of the revision component were performed with respect to a previously described triangle defining the placement and size of an idealcup. Impaction bone allo-grafting techniques were employed to fill defects. A minimum of 40% implant contact to host bone, especially in the weight-bearing dome region was attained in all cases and a minimum of 2 screws supplemented fixation to the ilium. Clinical evaluation comprised the HSS score and a patient assessment questionnaire (PAQ). Radiographically, cups were examined for filling of defects, ingrowth, graft consolidation, and stability. Results: The mean HSS score improved from 18 to 33 out of a maximum of 40. The mean superior bone defect was 18 mm (range 10 – 25mm) and the mean medial bone defect was 7 mm (range 0 – 22mm). All the cement-less acetabular components were bone ingrown with the exception of one stable fibrous union. Allograft incorporation occurred at a mean of 7 months after surgery. Neither the status of Kohler’s line nor the Paprosky class correlated with eventual radiographic or clinical results. Discussion: We present a simple method of evaluation of acetabular bone deficiency on the A-P pelvis radiograph employing a triangle that locates the ideal center of rotation of the hip. Superior bone loss upto 25 mm and medial migration as much as 22 mm has been successfully reconstructed employing impacted, cancellous allograft, large porous coated hemispherical Cementless acetabular components and screw fixation with excellent outcomes at intermediate-follow-up. Larger defects necessitate complex reinforced cage reconstruction

Materials and methods: From 1993 to 2001 in 20 patients with rheumatoid arthritis 24 total shoulder arthroplasties were performed. Concerning 19 Biomet total shoulder arthroplasties of which one glenoid component and one humeral component were cemented for optimal fixation. Five Aequalis total shoulder arthroplasties were performed, one with an uncemented glenoid component. The pre-operative diagnosis was rheumatoid arthritis in the whole Biomet-group. In the Aequalis-group there were four patients with rheumatoid arthritis and one patient with juvenile chronic arthritis. The mean age was 48 (19–76) years. The mean pre-operative range of motion was flexion 80 (40–150), external rotation 23 (–20 – 65) and abduction 55 (0–110) degrees. Pre-operative shoulder X-rays were staged according to Larssen. In the Biomet-group this resulted in eight times Larssen 3, nine times Larssen 4 and two times Larssen 5; in the Aequalis-group five times Larssen 4. All 24 operations were performed by a deltopectoral approach with 11 longitudinal osteotomies of the clavicula, 12 osteotomies of the lesser tubercle, two osteotomies of the greater tubercle and two osteotomies of the coracoid process; all without complications. Seven times a cancellous bone graft of the glenoid was performed. A rotatorcuff rupture was seen five times; in all cases this was closed primarily. A rotatorcuff release was performed four times. Two procedures were complicated: one longitudinal fissure of the humerus and one fractured greater tubercle, both in the Biomet-group. The after-treatment for all shoulder arthroplasties was functional with use of a collar ‘n cuff accompanied by intensive physiotherapy with increasing load of use. Results: No (sub)dislocation was seen or revision surgery was performed within six weeks after operation. Eight cranial subdislocations and one caudal subdislocation occured and one lesion of the brachial plexus was diagnosed six weeks or more after operation in the Biomet-group. There were no complications in the Aequalis-group. The mean follow-up is 49 (4–93) months. The mean postoperative range of motion was flexion 79 (20–150), external rotation 36 (0–75) and abduction 62 (0–150) degrees. The mean visual analogue painscore (VAS) increased from 3, 3 pre-operatively to 7, 3 postoperatively. Radiolucent lines were seen nine times, cemented Biomet humeral component 1x, uncemented Biomet glenoid component 7x and around cemented Aequalis glenoid component 1x. Two uncemented Biomet glenoid components showed medial migration. None humeral components showed migration. Two times a screw breakage was seen. Revision surgery was performed in two patients with subdislocation in the Biomet-group; a thicker humeral head was placed both times. One with good result and one re-subdislocated due to a lesion of the brachial plexus. Discussion: in 24 total shoulder arthroplasties no loosening of the humeral component occured. Loosening was seen in two glenoid components (8, 3%) although there was no indication to perform revision surgery. In these two cases a decreasing shoulder function was found. According to the pre-operative situation the range of motion post-operatively was unchanged but pain was obviously less

Aims

Restoration of proximal medial femoral support is the keystone in the treatment of intertrochanteric fractures. None of the available implants are effective in constructing the medial femoral support. Medial sustainable nail (MSN-II) is a novel cephalomedullary nail designed for this. In this study, biomechanical difference between MSN-II and proximal femoral nail anti-rotation (PFNA-II) was compared to determine whether or not MSN-II can effectively reconstruct the medial femoral support.