metatarsat osteotomy for the correction of metatarsus adductus

tarsometatarsal joint, as evidenced by the disparity in themedial and lateral foot borders (Fig. 1). The presentationof a convex lateral border and a concave medial borderwill be evident but depends on the degree of compensation.ln the uncompensated foot the convexity of theIateral border will be most marked with the styloid processof the fifth metatarsal very prominent. The medialarch may exhibit more height than expected for a childin his/her particular age group. ln contrast the totallycompensated deformity may reveal only a mild amountof convexity to the lateral border, a rather low or evenflattened medial arch and even some abduction of thedigits. Many authors have observed the separation of thehallux and the second digit and have suggested that thisseems more prevalent in the uncompensated and partiallycompensated foot types.During a thorough biomechanical evaluation, determinationof the presence of sagittal and frontal planeabnormalities must be made. This will affect the surgicalstrategy. The presence of a gastrocnemius orgastrocnemius-soleus equinus must be addressed toinsure the success of a metatarsus adductus repair.Evaluation of subtalar joint motion is also of greatimportance. Finally, the presence of an uncompensatedrearfoot varus if present must also be addressed.The forefoot should be examined in the standardfashion, the subtalar joint should be in its neutral position,the midtarsal joint should be locked. This willpermit an accurate appraisal of the metatarsal alignmentin all three planes. If a true transverse plane deformityexists, the metatarsal heads will all be aligned on thesame transverse plane. Any difference in elevation betweenmetatarsals can be compensated at the time ofsurgery. Careful preoperative planning will help to ensurea successful outcome. A gross frontal plane deformitymay exist in the form of a rigid forefoot varus. Actualdetermination of inversion of the metatarsals is notclinically possible.A common radiographic finding that is difficult toquantify clinically is the degree of adduction of eachmetatarsal. There may be an actual increase in the degreeof adduction of each metatarsal from lateral to medialwith the greatest amount being present in the firstmetatarsal. This can be considered as the domino effect.Another parameter to consider is the degree of flexibilitypresent in the deformity. A rigid metatarsus adductusdeformity will require more aggressive treatmentthan a flexible deformity. Postoperative casting andsplinting will be of assistance in reducing the adductusin the flexible deformity.Fig. 't. Clinical representation of resistant metatarsus adductus.Consideration of the presence of functional halluxlimitus must be made. Functional hallux Iimitus is theinability of the great toe to extend over the first metatarsalwhen the heel is lifting off the ground. This createsa sagittal plane motion blockade at the first metatarsophalangealjoint which must be compensated for atthe level of the midtarsal joint or ankle joint. The endresult is an accentuation of the deformity through anadductory twist at heeloff. This can be corrected at thetime of surgery by plantarflexing the first metatarsal andincreasing the declination and stability of the first ray.RADIOGRAPHIC EVATUATIONSThe diagnosis of metatarsus adductus is generallymade by clinical evaluation. Radiographic studies do contributeto determining the extent of the deformity as wellas providing greater insight to the osseous relationships.Full weight-bearing dorsoplantar and lateral views areperformed and used not only for determination ofangular relationships but to evaluate the osseous maturityof the foot (Fig. 2).The dorsoplantar view is of primary importance fordetermination of the metatarsus adductus angle. Thereare two methods currently used. The first depends ondefining the longitudinal axis of the lesser tarsus. Thisis accomplished by plotting a series of points beginningwith the medial most aspect of the first metatarsalcuneiform joint followed by the medial most aspect ofthe talonavicular joint, the lateral most aspect of the fifthmetatarsal cuboid joint, lastly the lateral most aspect ofthe calcaneocuboid joint. Two lines are then drawn, oneconnecting the medial points and one connecting thelateral points. Each of these lines is then bisected anda third line is drawn connecting the bisect points acrossthe midfoot. A fourth line is then constructed perpen-243