Purpose of the study: Mycetoma designates an inflammatory pseudotumour caused by fungal or bacterial agents with a slow chronic course and characterised by the emission of species-specific grains through fistules. Like the foot, the knee is a weight-bearing zone which can lead to mycetoma of soft tissue and/or bone or articular tissue. The purpose of this work was to study the frequency of the different clinical forms and report medical and surgical outcomes of the localisation.

Material and methods: This was a retrospective analysis of consecutive files collected over a 20-year period from July 1988 to 2008 including a total of 267 cases. Twentyfive patients (22 male 3 female) had an articular or peri-articular mycetoma of the knee joint. Mean age was 31.8 years (range 18–59). The right knee was involved in 17 cases and the left in eight. Duration of symptoms was 2.2 years (range 1–25 years). Antibacterial treatment with sulfamethoxazole and exclusively for actinomycetoma was given for 10 months at least and antifungal treatment with ketoconazole as adjuvant treatment with surgery for maduromycetomas. This orthopaedic surgery was radical (three above-knee amputations) or conservative (directed healing for 5, first-intention surgery for 5 with a flap for 3 and with a graft for the others).

Results: The knee accounted for 9.23% of the localizations in our series, most common after the foot and ankle. Twenty cases were exclusively maduromycetomas with black grains; the five others were actinomycetomas: 3 red grain, 1 white grain and 1 yellow grain. The topographic forms were predominantly anterior localization: 15 cases (versus popliteal in two, the entire knee in four and unknown in four). According to the Bouffard classification, the lesions were: diffuse (n=20), polyfisutulised (n=20), sclerohypertrophic (n=1) versus two localized encapsulated forms. Local spread led to bone and joint involvement in six patients, mycosis arthritis in three complicated by a pathological fracture of the patella. At last follow-up, there have been three recurrences with limited flexion in four patients.

Discussion: Articular or extra-articular mycetoma of the knee is an infectious dermato-orthopaedic disease dominated by fungal infection. Treatment is particularly difficult in advanced stage disease, medical and surgical management can be proposed with cancerological type resection.

Purpose of the study: Bipolar dislocation of the first metatarsal, also called floating metatarsal, remains a rare traumatic injury of the first ray of the foot. This is an acute unstable post-traumatic metatarsophalangeal and cuneometatarsal injury occurring simultaneously or successively. Most earlier reports have been single case reports. We report here three successive cases in adults to study the mechanism of the injury, the clinical forms and the different therapeutic modalities.

Material and method: The patients were three males aged 35 years on average who presented a bipolar dislocation of the first metatarsal.

Results: The causal event was an automobile accident for two patients and a work accident for one. There was an open wound in two cases over the metatarsophalangeal joint. Orthopaedic metatarsophalangeal reduction was achieved in two cases and open cuneometarsal reduction in one. The cuneometatarsal reduction was maintained with a pin for six weeks. The auto-reduction was then continued.

Discussion: Described for the first time by English as a paired dislocation, in 1997 Liebner coined the term of a floating metatarsal. We were able to identify eight publications in the literature. The causal mechanism would be successive dislocation of themetatarsophalangeal joint first followed by the cuneometatarsal joint. The metatarsophalangeal dislocation was dorsal in two patients and lateral in one. The sesamoid girdle remained intact (Jahns 1) and in all cases followed the first phalanx in its displacement (Garcia Mata S+). The cuneometatarsal dislocation was dorsal in all cases. The skin opening involved the plantar surface in one case and was medial in the other, allowing externalisation of the first metatarsal head. The floating metatarsal was isolated in one case and associated with a fracture of the second metatarsal in two. Primary reduction of the metatarsophalangeal joint then the cuneometatarsal joint was achieved in all cases. Irreducibility due to a button effect was noted in one case. At minimum three months follow-up, there has been no evidence of deformity. The foot has remained pain free with correct shoe wearing. The control x-rays have not shown any subluxation.

Conclusion: The floating first metatarsal is an exceptional foot injury. Primary reduction of the metatarsophalangeal joint appears to be the rule. Adequate primary treatment ensures satisfactory outcome.