Very long-term results of post-traumatic bone defect reconstruction by the induced membrane technique.

INTRODUCTION: The induced membrane technique for bone defect reconstruction is now well recognized, and short-term results for bone healing are consistent between published reports. OBJECTIVES: To assess very long-term functional results in post-traumatic reconstruction using the induced membrane technique. METHOD: Results for 18 patients undergoing bone defect reconstruction by induced membrane were retrospectively analyzed at 10 to 22years' follow-up. Initial lesions were multitissue with infection in 14 cases. Reconstruction concerned the tibia in 14 cases, and the humerus, elbow, radius or ulna in 1 case each. Soft-tissue reconstruction was performed in 17 cases, by free flap (n=8) or pedicle flap (n=9). Fixation used a single-plane external fixator in 15 cases, screwed plate in 1 case (humerus), or intramedullary nail in 1 case (ulna). There was 1 crossover from external fixator to internal plate fixation (radius). Assessment comprised radiology, functional assessment, clinical examination and patient satisfaction. All patients were followed up in individual consultation. RESULTS: Eight of the 14 patients with lower limb lesions had unrestricted walking distance; 4 resumed leisure sports. Limb shortening ranged from 0.5 to 4cm and was well-tolerated, although dorsiflexion was abolished or limited in most cases. Several patients underwent second procedures to improve limb function: ankle fusion, Achilles lengthening, tendon transfer, or realignment osteotomy. Radiology found a neotubular aspect, indicating peripheral densification and central resorption. Despite the multiple procedures, no patients regretted the original limb-conserving surgery. All reported that it took 2 to 3years after consolidation and resumption of walking to achieve stable final functional improvement. No recurrent sepsis in the reconstruction zone was found. CONCLUSION: The present results encourage implementing limb-conserving strategies in young patients after severe multitissue limb trauma, on condition that lesions are properly assessed, notably in terms of infection, and that the reconstruction protocol is feasible and has the patient's consent. LEVEL OF EVIDENCE: IV, retrospective series.

Induced Membrane Technique: Pearls and Pitfalls.

The induced membrane technique for reconstruction of bone defects has proved its effectiveness and is now widely accepted. The 2 stages procedure, implying a cement spacer in the first stage and a huge bone graft in the second stage, responds to rigorous technical details involving each phase of the procedure. Prerequisites for the technique, cement spacer, bone fixation, time between the 2 stages, grafting, and postoperative course are reported and discussed.

Circumferential bone grafting around an absorbable gelatin sponge core reduced the amount of grafted bone in the induced membrane technique for critical-size defects of long bones.

OBJECTIVES: The objectives of the study were to introduce a circumferential bone graft around an absorbable gelatin sponge core using an induced membrane technique, to assess its ability to reduce the required amount of graft and to maintain the bone graft, and to evaluate the clinical outcomes in the management of critical-size bone defects. PATIENTS AND METHODS: Circumferential bone grafting using a staged induced membrane technique for managing critical-size bone defects was performed in 21 patients. Postoperative computed tomography scans were performed 7days after Hemovac drain removal and 3 months after bone grafting. Volumetric measurements of the defect size, gelatin sponge proportion, and amount of grafted bone were performed by two independent observers using three-dimensional (3D) software. RESULTS: The critical-size defects were located at the metadiaphyseal area of 11 tibias, eight femurs, and two humeri. The average defect size was 8.9cm in length and 65.2cm3 in volume. The absorbable gelatin sponge core replaced 21.4% (average) of the defect volume. There was no significant deterioration in the shape of the grafted bone among the serial 3D models. Eighteen patients (86%) were healed radiographically at 9.1 months (average). CONCLUSION: Our study suggests that circumferential bone grafting in association with the induced membrane technique could reduce the required amount of bone graft and adequately maintain graft position and shape, with favourable clinical outcomes.

[Psychogenic contracture, a trap for the orthopedic surgeon]. / La contracture psychogène: un piège pour les chirurgiens orthopédistes.

Dysfunctional posture is an enigmatic pathological entity now attributed to a conversion reaction (formerly to hysteria). When localized to the limbs, the main clinical feature is a contracture of one or several articular segments inflexion or extension. Most of the time, the contracture is released by anesthesia. Patients should be managed with a psychopathological approach. However, some patients continue to be managed in a surgical department because the contracture became apparent after a trauma or surgical procedure. The orthopedic surgeon must be aware of this phenomenon in order to avoid unnecessary operations.

The concept of induced membrane for reconstruction of long bone defects.

Clinical, experimental, and fundamental studies have shown the interest of a foreign body-induced membrane to promote the consolidation of a conventional cancellous bone autograft for reconstruction of long bone defects. The main properties of the membrane are to prevent the resorption of the graft and to secrete growth factors. The induced membrane appears as a biological chamber, which allows the conception of numerous experimental models of bone reconstruction. This concept could probably be extended to other tissue repair.

Bone regeneration in long-bone defects: tissue compartmentalisation? In vivo study on bone defects in sheep.

Regeneration of living tissue varies with species, age and type of tissue, and undoubtedly with the biological and mechanical environment of the precise tissue. Autologous cancellous bone grafting is a well-known technique that provides bony regeneration. We investigated the efficiency of autologous bone grafting in a well-vascularised muscle environment, and additionally when isolated from the muscle and connected only to the bony environment. We designed a reproducible animal model producing a stable 3cm middiaphyseal bone and periosteal defect on sheep femurs and created a foreign-body membrane with a temporary poly-methylmethacrylate spacer. The foreign-body membrane had the outer dimension of the removed bone segment. We then ascertained the bony regeneration potential within the bone defect using autologous cancellous bone graft. Regeneration of bone is enhanced considerably by an autologous foreign-body membrane that separates the interfragmentary space from the muscular environment. This effect is independent of the autologous bone graft. The results suggest that bone behaves like a compartment that protects its specific humoral or its cellular environment, or both. Regeneration of bone can be enhanced by compartmentalisation of the bone defect.

Arterial vascularization of the proximal extensor carpi radialis brevis tendon.

The macroscopic arterial vascularization of the extensor carpi radialis brevis tendon was investigated in 12 elbows from cadavers to provide fundamental anatomic information of this tendon which has been associated with lateral epicondylitis. The arterial blood supply of the extensor carpi radialis brevis tendon was highly consistent. The radial recurrent artery vascularized the entire proximal tendon through direct branches to the medial and lateral border of the tendon forming a network of small vessels on the surface of the tendon. Important contributions were provided by the posterior branch of the radial collateral artery, and minor contributions were provided by the interosseous recurrent artery. The undersurface of the tendon seemed almost avascular. This observation suggests that potential hypovascular zones might be located at the undersurface of the tendon causing degeneration and partial tear of the tendon, and that this might be an etiologic factor in the pathogenesis of lateral epicondylitis. Additional microvascular studies are necessary to investigate this hypothesis.