Rescate articular con colgajo anterolateral del muslo / Joint rescue with anterolateral thigh flap

La preservación del nivel de amputación tanto de la extremidad superior como de la inferior, puede mejorar la función residual y el proceso de rehabilitación protésica de la misma. Ambas van a estar condicionadas por la longitud restante de la extremidad, la presencia o no de articulaciones operativas y la calidad de la cobertura del muñón. Presentamos 2 casos de amputaciones. El primero es un caso agudo de amputación traumática de extremidad superior a la altura del tercio proximal de antebrazo, que asocia avulsión cutánea circular desde el tercio medio del brazo y con articulación de codo conservada. El segundo, es la secuela de una amputación infracondílea de extremidad inferior por osteosarcoma que presenta fístulas cutáneas con drenaje supurativo por osteomielitis en el muñón tibial. En ambos pacientes realizamos cobertura con colgajo anterolateral de muslo anastomosado a la arteria radial en el caso de la extremidad superior, y a la arteria genicular descendente en la extremidad inferior. En los dos casos el postoperatorio transcurrió sin complicaciones, logrando preservar las articulaciones del codo y de la rodilla respectivamente, así como la posterior rehabilitación protésica. Consideramos que el colgajo anterolateral del muslo permite aportar tejido de buena calidad como cobertura del muñón de amputación. Dadas las características del tejido aportado y su volumen, es idóneo tanto para cobertura de defectos agudos como de déficits de almohadillado en casos crónicos (AU)

Sometimes, the severity of the trauma or the existence of a cancer force to amputate a limb. The prosthetic rehabilitation process and residual function will be influenced by the remaining length of the limb, the presence or absence of functional joints and the quality of the coverage of the stump. Two cases of amputations are shown. The former is an acute traumatic upper limb amputation at the level of the proximal third of forearm with skin avulsion from the middle third of the arm and the elbow joint preserved. The second case is the sequelae of an amputation below the knee due to lower extremity osteosarcoma, which was referred with suppurative draining cutaneous fistulas as a consequence of an osteomyelitis of the femur in the stump. In both patients the stumps were covered with anterolateral thigh flap anastomosed over the radial artery in the case of the upper extremity, and over the descending genicular artery in the lower extremity. In both cases the postoperative course was uneventful, preserving the elbow and knee respectively and allowing the subsequent prosthetic rehabilitation. We consider that anterolateral thigh flap is a suitable option for the treatment of the amputation stump. Given the characteristics of the tissue and volume provided by this flap, it is appropriate for coverage of acute defects and for padding deficits in chronic cases (AU)

The Scandinavian total ankle replacement (STAR).

Ankle joint arthritis is a condition that affects many people. Initial conservative treatment includes nonsteroidal antiinflammatory drugs, soft bracing, and ankle foot orthosis. When conservative management fails, surgical intervention is often considered. Previously an ankle joint fusion has been considered the "gold standard" to treat disabling ankle joint arthritis because early total ankle joint replacements had unacceptably high complication rates. However, early and midterm data have demonstrated that the Scandinavian Total Ankle Replacement (STAR) or Agility Total Ankle may be a reasonable alternative to an ankle joint fusion.

[Longevity factors in total trapezometacarpal prostheses]. / Facteurs de longévité des prothèses totales trapézométacarpiennes.

We report the long term outcome of the trapeziometacarpal prosthesis in a personal series of 13 cases with a follow-up ranging from 12 to 17 years. This ball and socket prosthesis with a metal on polyethylene pairing is cemented. Several modifications were performed along the years: such as increased range of motion, better fit between the metacarpal medullary canal and the proximal part of the stem and addition of a versatile, intermediate component in order to re-establish length of the first ray. The status of the metacarpo-phalangeal joint is critical. Natural hyperextension of this joint has been seen in about two-third of th normal individuals. If the metacarpal component become loose, the thumb column become shorter and hyperextension of the metacarpophalangeal joint is followed by an adduction contracture of the metacarpal which produces a shear force component on the cup and finally the loosening of the cup (sequential loosening). Keeping or re-establishing the length of the first ray is the major principle in the trapeziometacarpal prosthesis. On the other hand, metacarpophalangeal arthrodesis is a contraindication for a trapeziometacarpal prosthesis. Trapeziometacarpal prosthesis should only be used as a last resort when there is severe pain. If the dominant hand is involved, intensive use is a contraindication. The trapezium must be large enough to accommodate the cup. The author recommends a posterior approach which preserve the anterior ligaments and allows a proper bone resection and a good positioning of the cup.

[Metacarpophalangeal prosthesis modeling. Comparison of stress factors in a normal and a prosthetic metacarpophalangeal joint using finite element analysis]. / Modélisation d'une prothèse métacarpophalangienne. Comparaisons de l'état de contraintes par la méthode des éléments finis d'une articulation métacarpophalangienne saine et munie d'une prothèse.

INTRODUCTION: Prosthetic replacement of the metacarpophalangeal joints of long fingers is a problematical technique for the surgeon. The aim of the present study was to examine and compare, by means of finite element analysis, stress distribution in a normal metacarpophalangeal joint and to compare this with the findings in a similar joint with a prosthesis in order to better determine the risk of aseptic loosening, and also to examine possible solutions to limit these risks. METHOD: Finite element modelling was carried out using Abaqus software. Various criteria were taken into account including anatomical data, stress distribution, mechanical characteristics of the materials used, and different positions of the phalanx. RESULTS: A comparison of the results showed two significant stress distribution factors, i.e., a reduction of normal stress in the cortical bone of the finger fitted with a prosthesis; and the appearance of a flexion moment which completely modified the stress distribution throughout the metacarpal and therefore also in the opposite phalanx. DISCUSSION: To reduce the risk of aseptic loosening, two solutions were proposed: a) to reduce Young's module. The problem which arises, as in the case of total hip prosthesis, is that of finding a material with a Young's module which is closer to that of cortical bone, and which at the same time has a high elastic limit and breakage point and good biocompatibility; b) to reduce the inertia of the prosthesis, which seems the more likely of the two propositions, as it is based on the results of the modelling. The inertia of the prosthesis on stress distribution can be reduced by modifying two parameters, namely by producing a hollow section and shortening the structure of the prosthesis.