TIBIAL HEMIMELIA ; DO WE NEED A MODIFICATION OF THE CURRENTLY USED CLASSIFICATION SYSTEMS ?

* Abdelaal. Ahmed Hamed Kassem 1 , Morsy. Ahmad Fawaz. MD , Ashraf Rashad Marzouk. MD 3 and Ahmed Sleem. MD 3 . 1. Assistant lecturer of Pediatric Orthopedic Surgery, Faculty of Medicine, Sohag University, Egypt. 2. Lecturer of Pediatric Orthopedic Surgery, Faculty of Medicine, Sohag University, Egypt . 3. Lecturer of Orthopedic Surgery, Faculty of Medicine, Sohag University, Egypt. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History


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partially absent, or dysplastic with diastasis of the distal tibiofibular joint. In 2008, Weber viii believed that these earlier classifications were no longer useful for present-day requirements and suggested a new classification reflecting the severity of the morphology of the condition, clinical prognosis and the importance of any cartilaginous anlage. In either of the former classification systems, diastasis of the inferior tibiofibular joint appears to be related to different types of tibial hemimelia. ix ˒ x However, congenital isolated Congenital diastasis of the inferior tibiofibular joint also presents as a clinical problem such as talipes equinovarus, ankle diastasis, and leg-length inequality as many surgeons agree, xi despite the exact etiology is not well defined.
We report two cases of tibial hemimelia with complete diastasis of the tibia and fibula with separate skin envelop for each bone, the first case has complete diastasis, while the second case has partial diastasis, where the deformity could not be classified by any of the above systems and hadn't been reported before.
Case Report:-Case 1: A fifteen days old boy was presented to our pediatric orthopedic surgery unit with a deformed and bifid left leg. His parents were apparently healthy and non-consanguineous and his only brother was normal. His prenatal history was irrelevant. The baby looks generally well. The left knee was sublaxed with complete diastasis of tibia and fibula from the level of knee joint downward, with almost completely separate skin envelop for each bone, the fibula attain a flexed abducted position, while the tibia attain a flexion adduction position. Foot was articulated via dislocated joint with the fibula, while the tibia has no articulation with foot and widely separated from the fibula. Foot is supinated 180 degree with deficient first ray and the foot was smaller than the right side but most of the bones of the foot were present. The dorsalis pedis and tibialis posterior pulses were absent, but strikingly, the foot seems to elicit normal reflexes. There was partial active plantar flexion of the toes but no dorsiflexion. There was some movement in the subtalar or midfoot joints and passive pronation of the foot was possible. Patella could be palpated, a web is presented between the both bones of the leg. No hip subluxation or dislocation could be detected using the screening Barlow and Ortolani tests. Examination of the upper limbs and spine showed no abnormality, Routine abdominal and chest examination by a pediatrician was done and revealed no abnormality. Hip ultrasonographic examination was performed and showed no dislocation or subluxation in either hip joint. Abdominal ultrasonography as well as chest echocardiography was done and revealed no abnormality. Clinical appearance of the limb is shown in Fig.1. Radiographs and computed axial tomography showed a proximally displaced fibula with diastasis of both the proximal and distal tibiofibular joints, widely separated tibia and fibula, ankle joint is not present, deficient medial ray of the foot and medial femoral condyle hypoplasia. (Fig.2).

Case 2:
A four weeks old boy with a deformed right leg. There was a distal diastasis of tibia and fibula from the level of mid leg downward, with almost completely separate skin envelop for each part of the bone, the fibula attain a slightly flexed abducted position, articulating with the smaller sized inverted foot. Foot was articulated through a hyperflexible joint with the rudimentary fibula, while the tibia has no articulation with foot and widely separated from the fibula. No other apparent congenital anomalies (Fig. 3).
Treatment possibilities include amputation of the tibial stump with tibialization of fibula. However disarticulation knee with prosthesis replacement is not a far possibility. But we still wait a suitable time for either option. Lack of literature guidelines to treat such case makes the decision making a real clinical dilemma.

Discussion:-
Different classification systems for tibial hemimelia is present Although there is no many articles published about the gene location for tibial hemimelia. xii ˒ xiii Distal tibiofibular diastasis is a component of subtype in more than one of these classification systems. But as our case has complete diastasis, not only distal, and separate soft-tissue envelop for both tibia and fibula, our case does not fulfill the criteria of any recognized classification system. However, up to date no classification system entails the complete diastasis of tibia and fibula as a variant. Jones type 4, in which there is distal tibiofibular diastasis and foot is usually positioned between the divergent tibia and the fibula seems to be a possible classification. Our opinion to add these cases description to Kalamchi and Dawe classification as Type IV, As they mentioned different degrees of tibiofibular diastasis within the same soft tissue covering in type III.