Estabilización de fracturas Schatzker I de la meseta tibial. Estudio numérico comparativo mediante elementos finitos. Placas bloqueadas vs tornillos canulados

ResumenObjetivoLa estabilización quirúrgica de las fracturas SchatzkerI de meseta tibial se realiza principalmente mediante la colocación de tornillos canulados o mediante la aplicación de una placa con tornillos bloqueados proximales. En el postoperatorio, los pacientes realizan generalmente una descarga de 6 u 8 semanas. Usando el método de elementos finitos (EF), este estudio intenta analizar si la carga inmediata del paciente después de la cirugía genera un exceso de desplazamiento interfragmentario (DI).MétodosUtilizando un modelo validado de EF de paciente sano, el modelo tibial se reprodujo geométricamente, y se realizó una fractura SchatzkerI tipo a partir de radiografías y TAC de diferentes pacientes. Se modelizaron tornillos canulados de 6,5mm y una placa Polyax (Biomet Inc, EE.UU.), implantándose virtualmente en la tibia fracturada, y aplicando una fuerza de 400N, equivalente a 80kg de peso del paciente en bipedestación. Los DI se calcularon a partir del desplazamientos de diferentes nodos en el área fractuaria.ResultadosLos DI máximos calculados con la placa Polyax y los tornillos canulados fueron de 0,1-0,15mm y 0,25-0,3mm, respectivamente. Sin embargo, aplicando un peso de un 20% existía riesgo de fractura por compresión con los tornillos canulados. Con la placa Polyax se obtuvo una mejor distribución de las cargas, manteniéndose en zona segura por debajo de 100Mpa con la aplicación del 50% del peso del paciente.ConclusiónEste estudio sugiere que ambos sistemas tienen un resultado similar en cuanto al DI, pero la placa realiza una mejor distribución de las cargas en la zona de la fractura, permitiendo la carga parcial inmediata de un 50% del peso del paciente.AbstractObjectiveSurgical stabilization of split fractures of the lateral tibial plateau may involve percutaneous insertion of cannulated screws or more invasive implantation of locked plating systems. In any case, six to eight weeks of non-weight-bearing are recommended. By using the finite element (FE) method, this study aimed to assess whether immediate weight bearing can generate excessive interfragmentary motions (IM).MethodsA validated femur-tibia FE model of a healthy patient was used. The tibia model was reconverted into geometry, and a SchatzkerI fracture was re-created based on patient x-rays. Cannulated 6.5mm cancellous bone screws, and a Polyax tibial locked plating system (Biomet Inc, USA) were modelled, and virtually implanted into the fractured tibia geometry. An axial force of 400N pressed the femur model against the tibial plateau, simulating the weight of an 80Kg patient in bipedal stance. IM were calculated as the displacements between two nodes initially superimposed in the fracture areaResultsMaximum IM calculated with the Polyax and with the cannulated screw fixations were around 0.1-0.15mm, and 0.25-0.3mm, respectively. Both systems led to similar IM up to 80-90% of applied body weight. However, applying over 20% of the simulated body weight might lead to a risk of compression bone fracture. With the Polyax system, bone stresses were better distributed, and remained below 100MPa at 30% of body weight. Maximum stresses in the implants were about half the reported strength for the alloy simulated.ConclusionThis study suggested that IM caused by weight bearing might not impede bone healing in a fracture stabilized with either a Polyax locked plating system or cannulated screws. However, cannulated screw systems could lead to harmful load concentrations in the bone with immediate weight bearing. Plate systems will allow around 50% of immediate weight bearing

Fresh Osteochondral Resurfacing of the Patellofemoral Joint

Large osteochondral lesions of the knee in young patients continue to be a challenge for orthopaedic surgeons and the focus of continual research. This is particularly true if the injury is a consequence of a dysplastic trochlea and involves both articular surfaces of the biomechanically complex patellofemoral joint. To obtain a healthy and congruent patellofemoral joint, the use of a bipolar fresh osteochondral allograft transplantation of the patella and trochlea is one of the few options to biologically treat these injuries. This would achieve a replacement of the entire articular surface of the patellofemoral joint with a high number of viable chondrocytes and respect the unique structural characteristics of the cartilage. The aim of this study was to obtain symptomatic and functional improvements while delaying the timing of prosthetic surgery. We present a reproducible although demanding surgical technique to perform a bipolar fresh osteochondral allograft transplantation of the patella and trochlea

Primary lipoma arborescens of the knee may involve the development of early osteoarthritis if prompt synovectomy is not performed

Primary lipoma arborescens (LA) is a rare, benign intra-articular hyperplastic tumor that has been associated with osteoarthritis (OA). The aim of this study was to determine whether prompt synovectomy could avoid progressive joint degeneration in cases of primary LA of the knee. A review of currently available literature about the disease was carried out. The clinical, histological and radiological records of a series of nine knees with primary LA diagnosed and treated between 2002 and 2012 were retrospectively reviewed. Eight of the knees had histological confirmation of LA and none had evidence of condropathy on the initial magnetic resonance image or degenerative changes at the initial radiographic examination. At the final follow-up no evidence of OA was found in the three knees that underwent synovectomy when symptoms did not last more than 1 year. The five knees in which synovectomy was delayed developed progressive joint degeneration. In this series, primary LA of the knee involved the development of early osteoarthritis when prompt synovectomy was not performed. Timely synovectomy is strongly recommended, if not mandatory

20-Year Risks of Breast-Cancer Recurrence after Stopping Endocrine Therapy at 5 Years

The administration of endocrine therapy for 5 years substantially reduces recurrence rates during and after treatment in women with early-stage, estrogen-receptor (ER)-positive breast cancer. Extending such therapy beyond 5 years offers further protection but has additional side effects. Obtaining data on the absolute risk of subsequent distant recurrence if therapy stops at 5 years could help determine whether to extend treatment

Lateral Capsular Fixation : An Implant-Free Technique to Prevent Meniscal Allograft Extrusion

Although several surgical techniques have been described to perform meniscal allograft transplantation with good clinical results and although different methods of capsular stabilization can be found in the literature, there is no standard surgical technique to prevent a common complication in the most of series: the tendency to a radial displacement or extrusion of the transplanted menisci. We present a simple, reproducible, and implant-free technique to perform a lateral capsular fixation (capsulodesis) at the time of only the soft-tissue fixation technique of meniscal allograft transplantation in an effort to reduce or prevent the risk of graft extrusion. Using a minimum of two 2.4-mm tunnels drilled from the contralateral side of the tibia with the help of a regular tibial anterior cruciate ligament guide, a capsular attachment to the lateral tibial plateau is obtained

Triple Hybrid Tibial Anterior Cruciate Ligament Graft Fixation

Optimal graft fixation in anterior cruciate ligament reconstruction is critical. Several direct and indirect methods of graft fixation exist, each with advantages and disadvantages. This Technical Note describes a tibial hybrid anterior cruciate ligament graft fixation technique combining direct and indirect fixation methods, including autologous bone augmentation of the drill tunnel using cancellous bone fragments

Failed medial patellofemoral ligament reconstruction : Causes and surgical strategies

Patellar instability is a common clinical problem encountered by orthopedic surgeons specializing in the knee. For patients with chronic lateral patellar instability, the standard surgical approach is to stabilize the patella through a medial patellofemoral ligament (MPFL) reconstruction. Foreseeably, an increasing number of revision surgeries of the reconstructed MPFL will be seen in upcoming years. In this paper, the causes of failed MPFL reconstruction are analyzed: (1) incorrect surgical indication or inappropriate surgical technique/patient selection; (2) a technical error and (3) an incorrect assessment of the concomitant risk factors for instability. An understanding of the anatomy and biomechanics of the MPFL and cautiousness with the imaging techniques while favoring clinical over radiological findings and the use of common sense to determine the adequate surgical technique for each particular case, are critical to minimizing MPFL surgery failure. Additionally, our approach to dealing with failure after primary MPFL reconstruction is also presented

Fresh Osteochondral and Meniscus Allografting for Post-traumatic Tibial Plateau Defects

Large post-traumatic osteochondral defects of the proximal tibia in young active patients can be challenging because total or partial arthroplasties are to be avoided. The use of a fresh osteochondral allograft including its meniscus is one of the few options to biologically treat these injuries. Although the use of a fresh allograft is not easily accessible in some places and carries considerable logistical limitations, it is an alternative that provides viable chondrocytes to the defect. The inclusion of the meniscus in the osteochondral graft improves the results but also makes the technique even more demanding. We present a thorough description of this allograft transplantation to make it as reproducible as possible

Effectiveness of the Intratissue Percutaneous Electrolysis (EPI®) technique and isoinertial eccentric exercise in the treatment of patellar tendinopathy at two years follow-up

Aim: to show the effect of Intratissue Percutaneous Electrolysis (EPI®) combined with eccentric programme in the treatment of patellar tendinopathy. Methods: prospective study of 33 athlete-patients consecutively treated for insertional tendinopathy with Intratissue Percutaneous Electrolysis (EPI®) and followed for 2 years. Functional assessment was performed at the first visit, at three months and two years with the Tegner scale and VISA-P. Results: an average improvement in the VISA-P of 35 points was obtained. The mean duration of treatment was 4.5 weeks. Some 78.8% of the patients returned to the same level of physical activity as before the injury by the end of treatment, reaching 100% at two years. Conclusions: intratissue percutaneous electrolysis (EPI®) combined with an eccentric-based rehab program offers excellent results in terms of the clinical and functional improvement of the patellar tendon with low morbidity in a short-term period. Level of Evidence: Therapy, level 4