Fracture of a triple-polished tapered cemented femoral stem at the Morse taper after metal-on-metal primary total hip arthroplasty.

Total hip arthroplasty, one of the most successful orthopaedic procedures, is influenced by several variables. Corrosion at the modular junction is known as trunnionosis. Despite being reported infrequently, corrosion between the femoral head and the Morse taper can result in severe complications. Fracture of the femoral component in primary metal-on-metal (MoM) total hip arthroplasty at the Morse taper is an extremely rare event and can be associated with several risk factors. We report a case of corrosion at the Morse taper in a hybrid primary MoM total hip arthroplasty, resulting in Morse taper fracture with consequent femoral head entrapment inside the acetabular component. We hypothesise that some risk factors, such as age over 60years, active male patients, body mass index above 30kg/m2, large femoral heads, high-offset stems, 9/10 Morse taper and MoM-bearing surfaces, are associated with this mode of failure.

Gait instability may indicate liner failure in patients with total hip arthroplasty. A report of three cases.

Total hip arthroplasty is one of the most common and successful orthopaedic procedures performed worldwide. Uncemented modular acetabular components and highly cross-linked polyethylene liners are the implants of choice for most arthroplasty surgeons. However, despite their well-known benefits, highly cross-linked polyethylene liners are not without complications, such as rim fracture, rupture and dissociation. We report three patients with gait instability and radiographic subluxation due to highly cross-linked polyethylene liner failures evidenced during stage one revision surgery. The three patients were symptoms free, with no new instability episodes, and the radiographs showed no evidence of implant loosening at the most recent follow-up. Although it is a rare complication, these three cases highlight the importance of suspecting and evaluating highly cross-linked polyethylene liner failures in patients referred for gait instability with no history of previous trauma.

Six-stage revision surgery of a triple periprosthetic joint infection due to a delayed diagnosis of a bilateral psoas abscess: a case report.

CASE: We present a case of a 70-year-old woman with simultaneous periprosthetic joint infection (PJI) of both hips and left knee due to a bilateral psoas abscess. The patient underwent debridement and implants removal with the consequent reimplantation in a sequential six-stage revision surgery. At four years of follow-up and in spite of the patient's comorbidities and current PJI presentation, she maintains full activities of daily living without restrictions. CONCLUSION: Accurate and early diagnosis of a psoas abscess is crucial. This case report provides experience of a complex scenario, the decision-making involved and the outcomes of an underdiagnosed complication.

¿Es útil la artroscopia de cadera para el tratamiento de la displasia limítrofe?: análisis de casos y controles / Is hip arthroscopy useful in the treatment of borderline dysplasia?: a case-control study

INTRODUCCIÓN: Puesto que la artroscopia de cadera es controversial en el tratamiento de la displasia, nuestro objetivo fue analizar sus resultados clínicos y radiológicos en una cohorte de pacientes con displasia limítrofe y compararlos con controles con choque femoroacetabular (CFA). MATERIAL Y MÉTODOS: Analizamos retrospectivamente a un grupo de 29 pacientes con lesión labral secundaria a displasia limítrofe de cadera y a otro de 197 con CFA, ambos tratados con artroscopia, evaluando las reoperaciones y la supervivencia articular. El diagnóstico de displasia limítrofe se realizó con un ángulo centro-borde lateral mayor de 18° pero menor de 25°. El seguimiento promedio fue de 43 meses. Realizamos un análisis de regresión multivariada para evaluar la asociación de recirugía con distintas variables demográficas, radiológicas e intraoperatorias. RESULTADOS: Se registraron 7 complicaciones en el grupo CFA (una infección superficial tratada médicamente, 3 parestesias de nervio pudendo, una trombosis venosa profunda y 2 casos de calcificación heterotópica) y ninguna en el grupo displasia. Mientras que 5 pacientes del grupo CFA requirieron una nueva cirugía, ninguno del grupo displasia fue reintervenido (p = 0,38). Luego de ajustar por confundidores, la reoperación demostró una asociación muy fuerte con el hallazgo de lesiones osteocondrales, con un coeficiente de 0,12 (p < 0,001, IC95%=0,06-0,17). CONCLUSIÓN: La artroscopia de cadera resultó útil en el tratamiento de la displasia limítrofe, sin hallarse diferencias de supervivencia con el grupo CFA. Sugerimos indicarla en forma cuidadosa en la displasia, siempre que primen los síntomas de roce femoroacetabular por sobre los de inestabilidad

INTRODUCTION: Since arthroscopy remains a controversial treatment of hip dysplasia, our objective was to analyse its clinical and radiological results in a cohort of patients with dysplasia and compare them to controls with femoroacetabular impingement (FAI). MATERIAL AND METHODS: We retrospectively analysed a series of patients who underwent hip arthroscopy for the treatment of labral pathology; 29 of them with borderline hip dysplasia and 197 with FAI, comparing reoperations and joint survival. The diagnosis of borderline dysplasia was made with a lateral centre-edge angle greater than 18° but less than 25°. The average follow-up was 43 months. We performed a multivariate regression analysis to evaluate the association of reoperations with different demographic, radiological and intraoperative variables. RESULTS: Seven complications were registered in the FAI group (1 medically treated superficial wound infection, 3 pudendal nerve paraesthesias, 1 deep vein thrombosis and 2 heterotopic ossifications) and none in the dysplasia group. While 5 patients from the FAI group required a new surgery, none of the dysplasia group was re-operated (p=.38). After adjusting for confounders, reoperation showed a very strong association with the finding of osteochondral lesions during index surgery, with a coefficient of .12 (p<.001, 95%CI=.06-.17). CONCLUSION: Hip arthroscopy was useful in the treatment of borderline dysplasia, without non-inferior survival compared to the FAI group. We suggest indicating it carefully in dysplasia cases, whenever the symptoms of femoroacetabular friction prevail over those of instability

Is hip arthroscopy useful in the treatment of borderline dysplasia?: a case-control study. / ¿Es útil la artroscopia de cadera para el tratamiento de la displasia limítrofe?: análisis de casos y controles.

INTRODUCTION: Since arthroscopy remains a controversial treatment of hip dysplasia, our objective was to analyse its clinical and radiological results in a cohort of patients with dysplasia and compare them to controls with femoroacetabular impingement (FAI). MATERIAL AND METHODS: We retrospectively analysed a series of patients who underwent hip arthroscopy for the treatment of labral pathology; 29 of them with borderline hip dysplasia and 197 with FAI, comparing reoperations and joint survival. The diagnosis of borderline dysplasia was made with a lateral centre-edge angle greater than 18° but less than 25°. The average follow-up was 43 months. We performed a multivariate regression analysis to evaluate the association of reoperations with different demographic, radiological and intraoperative variables. RESULTS: Seven complications were registered in the FAI group (1 medically treated superficial wound infection, 3 pudendal nerve paraesthesias, 1 deep vein thrombosis and 2 heterotopic ossifications) and none in the dysplasia group. While 5 patients from the FAI group required a new surgery, none of the dysplasia group was re-operated (p=.38). After adjusting for confounders, reoperation showed a very strong association with the finding of osteochondral lesions during index surgery, with a coefficient of .12 (p<.001, 95%CI=.06-.17). CONCLUSION: Hip arthroscopy was useful in the treatment of borderline dysplasia, without non-inferior survival compared to the FAI group. We suggest indicating it carefully in dysplasia cases, whenever the symptoms of femoroacetabular friction prevail over those of instability.

Estudio comparativo radiológico y funcional del abordaje anterior directo versus abordaje posterolateral de cadera / Comparative study of radiological and functional outcomes following a direct anterior approach versus to a posterolateral approach to the hip

Objetivo: Realizar una comparación funcional y radiográfica de los resultados iniciales obtenidos con la utilización de los abordajes anterior directo (AAD) y posterolateral (PL) en la artroplastia total de cadera (ATC). Material y método: Estudio longitudinal prospectivo multicéntrico en 80 pacientes (80ATC). Cuarenta pacientes fueron intervenidos mediante AAD y 40 pacientes mediante abordaje PL. Se recogieron los siguientes parámetros clínicos: anestesia, abordaje, longitud de la incisión cutánea, duración de la cirugía, discrepancia de longitud, dolor, complicaciones, tiempo de ingreso, escala funcional de Harris (HHS) y satisfacción de los pacientes. En cuanto a los parámetros radiográficos, se recogieron ángulo de inclinación acetabular, anteversión acetabular, integración del cotilo, integración y orientación del vástago y longitud del miembro inferior. Resultados: Dolor postoperatorio: AAD 4puntos; PL 4,3puntos. Tamaño incisión: AAD14cm; PL 15cm. Duración media del ingreso hospitalario: AAD 2,8días; PL 3,4días. HHS a las 3semanas: AAD 87,5puntos, PL 84puntos; a los 2meses: AAD 92puntos, PL 91puntos. Se detectó hundimiento del vástago femoral en 4 pacientes AAD y en un paciente PL, y mala alineación en 9 casos del grupo AAD. Conclusiones: Nuestros resultados muestran una leve mejoría inicial del AAD en la recuperación funcional y en el dolor de los pacientes, lo que permite una menor estancia hospitalaria. Esta diferencia se compensa aproximadamente a los 2meses del postoperatorio. Asimismo, se ha detectado un mayor índice de complicaciones en el AAD con el uso de vástagos no cementados estándar

Objective: To compare clinically and radiologically the results obtained using both a direct anterior approach (DAA) and posterolateral (PL) approach in total hip arthroplasty (THA). Material and methods: Multicentric longitudinal prospective study in 80 patients (80 THA). Forty patients underwent total hip arthroplasty through DAA and 40 through a PL approach. The following clinical parameters were collected: anaesthesia, length of surgical incision, duration of the procedure, lower limb discrepancy, pain, complications, hospitalization time, Harris Hip Score (HHS) and subjective patient satisfaction. Radiological measures collected were acetabular tilt angle, acetabular component version, osteointegration and lower limb length. Results: Postoperative pain: DAA 4points; PL 4.3points. Incision length: DAA 14cm, PL 15cm. Mean hospital stay: DAA 2.8days, PL 3.4days. HHS at 3weeks: DAA 87.5points and PL 84points; at 2months: DAA 92points and PL 91points. Femoral stem subsidence was noticed in 4 patients from DAA and 1 from PL. Malalignment was reported in 9 cases from the DAA group. Conclusions: Our results show an initial advantage of the DAA group regarding functional recovery and pain that enabled shorter hospitalization time. This difference equalled out over 2months following the procedure. Likewise, we detected a greater complication rate in the DAA group using standard cementless stems

Comparative study of radiological and functional outcomes following a direct anterior approach versus to a posterolateral approach to the hip. / Estudio comparativo radiológico y funcional del abordaje anterior directo versus abordaje posterolateral de cadera.

OBJECTIVE: To compare clinically and radiologically the results obtained using both a direct anterior approach (DAA) and posterolateral (PL) approach in total hip arthroplasty (THA). MATERIAL AND METHODS: Multicentric longitudinal prospective study in 80 patients (80 THA). Forty patients underwent total hip arthroplasty through DAA and 40 through a PL approach. The following clinical parameters were collected: anaesthesia, length of surgical incision, duration of the procedure, lower limb discrepancy, pain, complications, hospitalization time, Harris Hip Score (HHS) and subjective patient satisfaction. Radiological measures collected were acetabular tilt angle, acetabular component version, osteointegration and lower limb length. RESULTS: Postoperative pain: DAA 4points; PL 4.3points. Incision length: DAA 14cm, PL 15cm. Mean hospital stay: DAA 2.8days, PL 3.4days. HHS at 3weeks: DAA 87.5points and PL 84points; at 2months: DAA 92points and PL 91points. Femoral stem subsidence was noticed in 4 patients from DAA and 1 from PL. Malalignment was reported in 9 cases from the DAA group. CONCLUSIONS: Our results show an initial advantage of the DAA group regarding functional recovery and pain that enabled shorter hospitalization time. This difference equalled out over 2months following the procedure. Likewise, we detected a greater complication rate in the DAA group using standard cementless stems.

No lower bacterial adhesion for ceramics compared to other biomaterials: An in vitro analysis.

BACKGROUND: Although there is some clinical evidence of ceramic bearings being associated with a lower infection rate after total hip arthroplasty (THA), available data remains controversial since this surface is usually reserved for young, healthy patients. Therefore, we investigated the influence of five commonly used biomaterials on the adhesion potential of four biofilm-producing bacteria usually detected in infected THAs. HYPOTHESIS: Ceramic biomaterials exhibit less bacterial adherence than other biomaterials. MATERIAL AND METHODS: In this in vitro research, we evaluated the ability of Staphylococcus aureus, Staphylococcus epidermidis ATCC 35984, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa to adhere to the surface of a cobalt-chromium metal head, a fourth-generation ceramic head, a fourth-generation ceramic insert, a highly-crossed linked polyethylene insert and a titanium porous-coated acetabular component. After an initial washing step, bacterial separation from the surface of each specimen was done with a vortex agitator. The colony-forming units were counted to determine the number of viable adherent bacteria. RESULTS: We found no differences on global bacterial adhesion between the different surfaces (p=0.5). E. coli presented the least adherence potential among the analysed pathogens (p<0.001). The combination of E. coli and S. epidermidis generated an antagonist effect over the adherence potential of S. epidermidis individually (58±4% vs. 48±5%; p=0.007). The combination of P. aeruginosa and S. aureus presented a trend to an increased adherence of P. aeruginosa independently, suggesting an agonist effect (71% vs. 62%; p=0.07). DISCUSSION: Ceramic bearings appeared not to be related to a lower bacterial adhesion than other biomaterials. However, different adhesive potentials among bacteria may play a major role on infection's inception. LEVEL OF EVIDENCE: IV, in vitro study.

Resultados de un vástago con cobertura completa de hidroxiapatita con un seguimiento mínimo de 5 años / Outcomes using wedge stem with full hydroxiapatite coverage with a minimum of 5 years' follow-up

Introducción. La artroplastia total de cadera (ATC) con vástagos no cementados es popular en las últimas décadas. La supervivencia de un implante es crítica, con una tasa de revisión menor al 10% a 10años como límite para su aceptación y comercialización. Objetivos. Analizar los resultados clínico-radiográficos con un vástago en forma de cuña no cementado con recubrimiento completo de hidroxiapatita (HA) y con seguimiento mínimo de 5años. Material y métodos. Estudio prospectivo. Utilización de vástago Element (Exactech) y copa no cementada con inserto crosslink pared posterior elevada y cabeza metálica de 32mm. Se realizó un abordaje posterolateral con retención del músculo piriforme. Seguimiento clínico a las 3 semanas, a los 3 y 6 meses, al año y años subsiguientes. Evaluación radiográfica base en el postoperatorio inmediato y comparación con los controles. Se registraron las complicaciones intraoperatorias y en los seguimientos. Resultados. Ciento catorce ATC en 104 pacientes: 54 mujeres y 50 hombres (52/48%), con seguimiento de 5,7años (rango, 5-6,2años) y con 56,8años de promedio de edad (rango, 42-75años). Evaluación inicial score Merle d’Aubigné pobre con mejora postoperatoria de 6,8 puntos. Score de Harris inicial de 47,3 puntos y, a la última consulta, de 93,1 puntos. Evaluación radiográfica: osteointegración de todos los vástagos. Hundimiento: 6 casos (5,3%) a 3meses de cirugía, promedio de 1,4mm (rango, 0-2,6mm) sin repercusión clínica hasta la actualidad. En 3 casos de hundimiento hubo fracturas intraoperatorias: una del trocánter mayor (se realizó un cerclaje tipo mochila) y 2 por fractura proximal en el área del calcar (tratadas con cerclaje circular). Evaluación subjetiva: 86 casos (82,6%) excelente, 9 pacientes (8,6%) buena, 6 casos (5,9%) satisfactoria y 3 casos (2,9%) pobre. Los resultados pobres coincidieron con pacientes que tuvieron las complicaciones mencionadas. No se detectó dolor femoral anterior. No se produjeron luxaciones o aflojamientos sépticos. No hubo pérdida de pacientes en el período de seguimiento. Todos los implantes se encuentran in situ al momento del último seguimiento. Conclusiones. La evaluación y el seguimiento radiográfico confirman buena osteointegración del vástago. Los resultados clínicos y subjetivos son prometedores. Con una buena técnica quirúrgica y sin complicaciones, el riesgo de aflojamiento aséptico impresiona ser mínimo o ausente (AU)

Introduction. Total Hip Arthroplsty (THA) using uncemented stems is a popular practice in the last decades. The implant survivorship is crtitical and a less than 10% revision at 10 years is been propesed for commercialization and use. Objective. To analyse the clinicoradiological results of an uncemented hydroxiapatite covered wedge stem with a 5 years minimum follow up. Material and methods. Prospective study, patients aged from 21-75years were included. All patients received an Element stem (Exactech) and uncemented cup with crosslink poly and 32 mm metal head, and posterior approach with piriformis retention was used. Scheduled clinical and radiographic evaluation at 3 weeks, 3-6 month, year and subsequent years using Harris Hip Score and Merle d’Aubigné Postel. Intraoperative and during follow up complications were recorded. Results. One hundred and fourteen total hip replacements in 104 patients: 54 females and 50 males (52%/48%). Follow-up of 5.7 years (range, 5-6.2years). Average age 56.8years (range, 42-75years). Clinical evaluation the Merle d’Aubigné score improved 6.8 points and from the initianl Harris Hip Score 47.3 to 93.1 points at last follow up. Radiographic evaluation shows osteointegration in all stems. And in 6 cases (5.3% at 3 months subsidence was detected, average 1.4 mm (range 0-2.6 mm) with no clinical manifestation, 3 cases of subsidence were associated to intraoperative fractures (1 greater trochanter and 2 in the calcar area, all resolved with wire cerclaje). Subjective evaluation: 86 cases (82.6%) excellent, 9 patients (8.6%) good, 6 cases (5.9%) satisfactory and 3 cases (2.9%) poor. All poor results linked to the intraoperative complications. No patient lost during follow up period. No femoral pain dislocation or aseptic or loosening detected. All implants were in situ at last follow up. Conclusions. The radiological results confirm the benefits of this type of stem with good osteointegration. The clinical and subjective results are promising. With good surgical technical and without complications the risk of aseptic loosening should be absent or minimal (AU)

Metaphyseal debonding of the Corail collarless cementless stem: report of 18 cases and case-control study.

AIMS: The Corail stem has good long-term results. After four years of using this stem, we have detected a small group of patients who have presented with symptomatic metaphyseal debonding. The aim of this study was to quantify the incidence of this complication, to delineate the characteristics of patients presenting with this complication and to compare these patients with asymptomatic controls to determine any important predisposing factors. PATIENTS AND METHODS: Of 855 Corail collarless cementless stems implanted for osteoarthritis, 18 presented with symptomatic metaphyseal debonding. A control group of 74 randomly selected patients was assembled. Clinical and radiological parameters were measured and a logistic regression model was created to evaluate factors associated with metaphyseal debonding. RESULTS: The prevalence of this complication was 2.1% in our series. In the multivariable model, the presence of a Dorr B-type proximal femur was associated with metaphyseal debonding (odds ratio (OR) 10.73, 95% confidence interval (CI) 2.31 to 49.97, p = 0.002), as was a body mass index > 25 kg/m2 (OR 6.85, 95% CI 1.06 to 44.28, p = 0.04). Smaller stems and the use of a polyethylene acetabular liner appeared to be protective when compared with metal and ceramic setting hard-on-hard bearings. CONCLUSION: We have described an uncommon but important mode of failure of the Corail stem. Surgeons should be aware of this phenomenon; overweight patients with Dorr B-type femurs and in whom hard bearings are used appear to be particularly at risk. Cite this article: Bone Joint J 2017;99-B:1435-41.

Outcomes using wedge stem with full hydroxiapatite coverage with a minimum of 5 years' follow-up. / Resultados de un vástago con cobertura completa de hidroxiapatita con un seguimiento mínimo de 5 años.

INTRODUCTION: Total Hip Arthroplsty (THA) using uncemented stems is a popular practice in the last decades. The implant survivorship is crtitical and a less than 10% revision at 10 years is been propesed for commercialization and use. OBJECTIVE: To analyse the clinicoradiological results of an uncemented hydroxiapatite covered wedge stem with a 5 years minimum follow up. MATERIAL AND METHODS: Prospective study, patients aged from 21-75years were included. All patients received an Element stem (Exactech) and uncemented cup with crosslink poly and 32 mm metal head, and posterior approach with piriformis retention was used. Scheduled clinical and radiographic evaluation at 3 weeks, 3-6 month, year and subsequent years using Harris Hip Score and Merle d'Aubigné Postel. Intraoperative and during follow up complications were recorded. RESULTS: One hundred and fourteen total hip replacements in 104 patients: 54 females and 50 males (52%/48%). Follow-up of 5.7 years (range, 5-6.2years). Average age 56.8years (range, 42-75years). Clinical evaluation the Merle d'Aubigné score improved 6.8 points and from the initianl Harris Hip Score 47.3 to 93.1 points at last follow up. Radiographic evaluation shows osteointegration in all stems. And in 6 cases (5.3% at 3 months subsidence was detected, average 1.4 mm (range 0-2.6 mm) with no clinical manifestation, 3 cases of subsidence were associated to intraoperative fractures (1 greater trochanter and 2 in the calcar area, all resolved with wire cerclaje). Subjective evaluation: 86 cases (82.6%) excellent, 9 patients (8.6%) good, 6 cases (5.9%) satisfactory and 3 cases (2.9%) poor. All poor results linked to the intraoperative complications. No patient lost during follow up period. No femoral pain dislocation or aseptic or loosening detected. All implants were in situ at last follow up. CONCLUSIONS: The radiological results confirm the benefits of this type of stem with good osteointegration. The clinical and subjective results are promising. With good surgical technical and without complications the risk of aseptic loosening should be absent or minimal.

Bilateral simultaneous femoral neck fracture mimicking abdominal pain in a cerebral palsy patient.

Simultaneous bilateral femoral neck fractures are unusual lesions, generally associated with an underlying condition which causes impaired bone mineralization, triggered by an increased bone stress. We present a 24-year-old cerebral palsy patient, who was previously evaluated in another institution due to inability to walk, interpreted as abdominal pain. No alteration in blood analysis or abdominal X-rays was found. As no response to treatment was observed, a new abdominal X-ray was taken, which incidentally depicted bilateral medial femoral neck fracture. He was referred to our practice after a resection arthroplasty was offered in another institution. After admission, bilateral one-stage THA was performed. Several reports emphasize bone disease as a major precipitating factor, and there is an increased incidence of hip fractures in chronic epilepsy, renal osteodystrophy, and chronic steroid use. Femoral head resection has been proven to be effective in immobilized patients, whereas this was not a reasonable option in this patient who presented walking ability. Despite the treatment election, primary care physicians should be aware of and alert to the possibility of fractures in patients with neurological disorders and calcium metabolism alterations. Late diagnosis of orthopedic injuries in this type of patients may lead to permanent disability.

The use of femoral struts and impacted cancellous bone allograft in patients with severe femoral bone loss who undergo revision total hip replacement: a three- to nine-year follow-up.

We determined the midterm survival, incidence of peri-prosthetic fracture and the enhancement of the width of the femur when combining struts and impacted bone allografts in 24 patients (25 hips) with severe femoral bone loss who underwent revision hip surgery. The pre-operative diagnosis was aseptic loosening in 16 hips, second-stage reconstruction in seven, peri-prosthetic fracture in one and stem fracture in one hip. A total of 14 hips presented with an Endoklinik grade 4 defect and 11 hips a grade 3 defect. The mean pre-operative Merle D'Aubigné and Postel score was 5.5 points (1 to 8). The survivorship was 96% (95% confidence interval 72 to 98) at a mean of 54.5 months (36 to 109). The mean functional score was 17.3 points (16 to 18). One patient in which the strut did not completely bypass the femoral defect was further revised using a long cemented stem due to peri-prosthetic fracture at six months post-operatively. The mean subsidence of the stem was 1.6 mm (1 to 3). There was no evidence of osteolysis, resorption or radiolucencies during follow-up in any hip. Femoral width was enhanced by a mean of 41% (19% to 82%). A total of 24 hips had partial or complete bridging of the strut allografts. This combined biological method was associated with a favourable survivorship, a low incidence of peri-prosthetic fracture and enhancement of the width of the femur in revision total hip replacement in patients with severe proximal femoral bone loss.

Conjugated Linoleic Acid (CLA) content of meat from three muscles of Massese suckling lambs slaughtered at different weights.

Eighteen Massese male lambs, fed mainly maternal milk were slaughtered at 11, 14 and 17kg. Samples of Longissimus Dorsi (LD), Triceps Brachii (TB) and Semimembranosus (Sm) muscles were collected. Milk from the lamb's dams was sampled weekly. Fatty acid composition of milk and meat was determined. TB was the fattest muscle, Sm the leanest one and LD showed an intermediate value of total lipids, while the weight at slaughter did not influence total intramuscular fat content in any muscle. Although slaughter weight slightly affected overall fatty acid composition of muscles, rumenic acid and total CLA content in TB and Sm, but not in LD, significantly increased with slaughter weight. As regard milk fatty acid composition, the contents of total CLA, RA and others minor CLA isomers decreased during the first four weeks after lambing and then increased at the last control (five weeks). The animals slaughtered at a live weight of 14 and 17kg showed a greater SCD enzyme activity (estimated by product/substrate ratio) and a higher rumen activity (estimated by means of branched chain and odd chain fatty acid content in meat) than animals slaughtered at 11kg. Cis-7, trans-9 CLA content significantly increased with the slaughter age in TB and SM, while trans-7, trans-9 CLA, only increased in TB, and cis-8, cis-10 CLA, only increased in SM. Further studies are needed in order to verify weather the different behaviour of RA in LD muscle may be due to differences in muscle metabolism or fatty acid utilisation.

Viability of impacted bone allografts under metal mesh at the calcar in revision surgery of the hip.

Metal meshes are used in revision surgery of the hip to contain impacted bone grafts in cases with cortical or calcar defects in order to provide rotational stability to the stem. However, the viability of bone allografts under these metal meshes has been uncertain. We describe the histological appearances of biopsies obtained from impacted bone allografts to the calcar contained by a metal mesh in two femoral reconstructions which needed further surgery at 24 and 33 months after the revision procedure. A line of osteoid and viable new bone was observed on the surface of necrotic trabeculae. Active bone marrow between these trabeculae showed necrotic areas in some medullary spaces with reparative fibrous tissue and isolated reactive lymphocytes. This is interpreted as reparative changes after revascularisation of the cancellous allografts. These pathological findings are similar to those reported in allografts contained by cortical host bone and support the hypothesis that incorporation of morcellised bone under metal meshes is not affected by these devices.

Locking compression plate fixation of Vancouver type-B1 periprosthetic femoral fractures.

BACKGROUND: Fractures occurring at or near the distal tip of a hip prosthesis with a stable femoral stem (Vancouver type-B fractures) are associated with many complications because of the inherently unstable fracture pattern. Locking compression plates use screws that lock into the plate allowing multiple points of unicortical fixation. Such unicortical fixation may lower the risk of damage to the cement mantle or a stable femoral stem during the treatment of a periprosthetic femoral fracture. The purpose of this study was to analyze clinically and radiographically a group of patients with a Vancouver type-B1 periprosthetic femoral fracture treated with open reduction and internal fixation with use of a locking compression plate. METHODS: Fourteen consecutive patients (fourteen hips) with a Vancouver type-B1 periprosthetic femoral fracture were treated with a locking compression plate. There were five men and nine women with an average age of sixty-eight years at the time of fracture. All of the fractures occurred after a total hip arthroplasty performed with cement, and eleven of the arthroplasties were revisions. In addition to the plate, cortical strut allografts were used to stabilize five fractures. The patients were assessed clinically and radiographically. RESULTS: The average duration of follow-up was twenty months. Eight fractures healed uneventfully at an average of 5.4 months. Three treatment constructs failed with fracture of the plate within twelve months after surgery. An additional three constructs also failed because of plate pullout. All failures except one occurred in constructs in which a cortical strut allograft had not been utilized. CONCLUSIONS: On the basis of the high failure rate in this series of patients, locking compression plates do not appear to offer advantages over other types of plates in the treatment of type-B1 periprosthetic femoral fractures. Despite the potential to preserve the cement mantle, the locked screws did not appear to offer good pullout resistance in this fracture type. We believe that supplementation with strut allografts should be used routinely if this type of locking compression plate is selected to treat these fractures.

Separation of the apex hole eliminator screw in four failed hybrid total hip arthroplasties.

Advancement or separation of the apex hole eliminator screw in uncemented Duraloc 100 cups (DePuy, Warsaw, Indiana, USA) has been recently reported as a radiographic finding without clinical effects. We report 4 patients with a separation of the apex hole eliminator screw in Duraloc 300 uncemented cups and aseptic failures of a hybrid total hip arthroplasty (acetabular osteolysis and femoral stem loosening). Revision surgery was performed when disabling pain and radiographic signs of loose components were present. Although difficult to determine, a relationship between the screw migration and the failure could have existed in these cases. Migration of the screw might not only be interpreted as a radiographic, clinically irrelevant finding. Its presence should alert the orthopaedic surgeon that the prosthesis is exposed to high intraarticular fluid pressures.

Modular femoral head dissociation after dislocation and entrapment in reconstruction ring: a case report.

Dissociation of modular components is an infrequent potential complication characteristically unique to modularity. We present a patient in whom dissociation of the modular femoral head occurred at attempted closed reduction after dislocation, with the intraoperative findings including entrapment of the head between the rim of a reconstruction ring and the acetabular bone. In the case a dislocation in a patient that was previously reconstructed with a reinforcement ring and a modular femoral stem occurs, dissociation of the modular head should be considered as an extremely uncommon complication that does not outweigh the advantages given by modularity.

Acetabular reconstruction with impacted bone allografts and cemented acetabular components: a 2- to 13-year follow-up study of 142 aseptic revisions.

We reviewed the clinical and radiological results of 131 patients who underwent acetabular revision for aseptic loosening with impacted bone allograft and a cemented acetabular component. The mean follow-up was 51.7 months (24 to 156). The mean post-operative Merle D'Aubigné and Postel scores were 5.7 points (4 to 6) for pain, 5.2 (3 to 6) for gait and 4.5 (2 to 6) for mobility. Radiological evaluation revealed migration greater than 5 mm in four acetabular components. Radiological failure matched clinical failure. Asymptomatic radiolucent lines were observed in 31 of 426 areas assessed (7%). Further revision was required in six patients (4.5%), this was due to infection in three and mechanical failure in three. The survival rate for the reconstruction was 95.8% (95% confidence interval 92.3 to 99.1) overall, and 98%, excluding revision due to sepsis. Our study, from an independent centre, has reproduced the results of the originators of the method.