Purpose of the study: The sub-fibular bone occurs as an ossicle adjacent to the apex of the lateral malleolus. Observed in 2% of children, it is generally a fortuitous x-ray discovery considered as a normal variant. Its rather high frequency in victims of former ankle trauma suggests the hypothesis of a traumatic origin. We have observed a high frequency of subfibular bone associated with functional ankle instability after trauma in children. The purpose of this study was to evaluate the function outcome after inverted ankle trauma in children with an avulsion fracture of the distal point of the lateral malleolus or a subfibular bone. We tested the hypothesis that presence of a subfibular bone corresponds to a sequelae of a former trauma and that it could led to a high frequency of mid- and long-term ankle stability.

Material and methods: This series included 50 children with a diagnosis of subfibular bone identified after trauma with ankle inversion. At least six months after the trauma, stability measurements were made to quantify residual functional instability of the ankle. Clinical signs of subjective instability were noted. A standardized protocol for stress x-rays was performed using the trauma-free contralateral ankle as the control.

Results: In more than 50% of patients, presence of a subfibular bone was associated with clinical signs of functional instability one year after ankle trauma. The quantitative measures of joint stability confirmed the significant presence of this instability, rarely associated with residual ligament laxity.

Discussion: In our series, most of the subfibular bones were interpreted as fracture-avulsions of the point of the lateral malleolus.

Conclusion: Discovery of a subfibular bone after an ankle «sprain» in children is a significant risk factor for subjective sequelar ankle instability after orthopedic treatment with a plaster cast.

Purpose: Blast injury of the hand generally occurs during manipulations of unstable explosives. The explosion greatly damages the first commissure. The aim of this study was to define a classification system useful for establishing therapeutic strategy.

Material and methods: From 1988 to 2002, we treated eight patients (nine hands, five dominant) with blast injury of the hand. Mean age was 24 years. Five hands were injured during manipulation of firecrackers and four during manipulation of munitions. The thumb was amputated on five hands, including three cases of index or medius amputation. Thumb revascularisation was successful in only one case. Two proximal thumb amputations were treated by twisted toe transfer. For one of these patients, the transfer was prepared by translocation of M2 on M1 using an inguinal flap. Two patients required a composite osteocutaneous reconstruction of M1 using the index as the bone source. In one final patient, lesions were limited to soft tissues.

Discussion: Blast injured hands present several types of lesions: extensive soft tissue damage, diffuse vessel damage making revascularisation difficult or impossible, combined thenar and joint lesions leading to secondary closure of the first commissure. We distinguished three stages. Stage 1 involves only muscle and skin damage. After opening the first commissure with M1-M2 pinning, cover is achieved with a posterior interosseous flap or a skin graft. Stage 2 involves osteoarticular damage. Bone loss of M1 and P1 is often associated with dislocation. Bone reconstruction is often achieved using the distally amputated or greatly damaged thumb. Stage 3 involves amputation or devascularisation of the thumb. Reconstruction of the thumb is particularly difficult in these cases. If the amputation is distal beyond MP, M1 lengthening or classical toe transfer can be used. If the amputation is proximal, prior M1 reconstruction is required with a skin envelope using M2 fashioned with an interosseous or inguinal flap, followed by twisted toe transfer of the second toe. Stage 3 translocations are difficult because of the often damaged index and scar formation.

Purpose: Prolonged denervation resulting from deferred nerve repair or long distance between the muscle and the repaired nerve, leads to major alterations concerning muscle fibre degeneration and their replacement by fibrous or fatty tissue. These structural modifications of the muscle are unfavourable for reinnervation and consequently affect the final functional outcome after peripheral nerve repair with its corollary of reduced muscle force. The purpose of this work was to assess the potential for regeneration of denervated-reinnervated muscles and their improvement with adjuvant cell therapy using in situ transfer of cultured autologus satellite cells.

Material and methods: This work was conducted with the tibialis anterior muscle in different groups of New Zealand rabbits. The experimental model was a sectioned common fibular nerve and immediate or deferred (two months) microsurgical nerve suture. In vivo functional measurements and histomorphological analyses were performed four months after nerve repair.

Results: Reinervation led to loss of mucle weight and maximal force (Fmax) which were greater with longer deferral of repair. Transfer of satellite cells performed immediately after reinervation did not improve muscle properties. Conversely, transfer of satellite cells two months after nerve suture increased Fmax 25% (p < 0.01) and muscle weight 28% (p = 0.005) in comparison with control muscles undergoing reinervation without cell transfer. Furthermore, the morphology of the muscle was improved as demonstrated by anti-myosine labelling studies.

Discussion: Adjuvant cell therapy allows, in certain conditions, an improvement in functional recovery after peripheral nerve injury. Its clinical application still raises a certain number of ethical issues but taking into consideration data currently available, it would be reasonable to propose this therapeutic approach in humans to reduce involution of the denervated muscle and improve its receptivity for regenerating axons after peripheral nerve repair. Better post-operative results could be expected

Purpose: Recovery of muscle function after nerve repair remains incomplete despite progress in microsurgical techniques. Potential for muscle recovery could be greatly improved. The purpose of our study was to demonstrate the functional impact of exogenous satellite cells in degenerated muscles.

Material and methods: We used the anterior tibialis muscle (Ta) in rabbits (n=24) as our experimental model. Muscle degeneration was created by bilateral injections of cardio-toxin into the Ta. Five days later, the left Ta was injected with autologous satellite cells (SC) at multiple points. The same volume of culture medium was injected into the right Ta. Two months later, maximal isometric muscle force and stress resistance of the Ta was measured. Histoimmuno-chemical labellings were made.

Results: The volume of cardiotoxin injected created two categories of muscles: recovery of former function was not possible with low dose cardiotoxin injections. Maximal isometric muscle force was less than 35% of the control. Transfer of SC restored nearly normal muscle force. Resistance to stress followed the same pattern. Recovery of maximal muscle force was possible with high-dose cardiotoxin injections. Resistance to stress was greater than the control (+ 35%). Transfer of SC did not modify results.

The weight of the Ta increased for both cardiotoxin doses. There was an increase in the size of the fibres with or without SC transfer.

Discussion: Injection of cardiotoxin induced muscle degeneration. With greater muscle degeneration, regeneration of muscle capacity was greater. Transfer of SC improved the functional result when muscle degeneration was incomplete. Improved resistance to stress after injection of high-dose cardiotoxin could result from changes in muscle myosin and fibrillary structure.

Conclusion: Further studies are needed before clinical application to better understand the underlying mechanisms operating with satellite cell injections. Many applications could be proposed, particularly for surgical nerve repair, ischaemic heart failure, and myopathy.