Point-Counterpoint: Should The Lapidus Replace The Closing Base Wedge Osteotomy?
Yes, this author says the Lapidus facilitates better first ray stability, allows more intraoperative flexibility and is an easier procedure to perform and fixate. By Babak Baravarian, DPM As the field of foot and ankle surgery has evolved, there has been a dramatic shift in hallux abducto valgus surgery. Currently, the primary treatment goals are ensuring proper alignment of the first metatarsal in both the sagittal, frontal and transverse planes, and facilitating the best long-term outcome. When it comes to realignment of the first ray in all three planes and minimizing the chance of recurrence, the Lapidus bunionectomy is the ideal surgical procedure. There are several reasons for using a Lapidus bunionectomy in comparison to a closing base wedge procedure. Employing the Lapidus bunionectomy enables one to achieve a greater level of first ray stability and allows for unlimited correction of the first ray in all three planes of motion with the possibility of intraoperative correction of alignment. The Lapidus bunionectomy virtually prevents the possibility of the bunion deformity from reoccurring. The Lapidus is also far simpler to perform and fixate in comparison to the closing base wedge procedure. As noted by Morton in his studies, the first ray lacks stability when one compares it to the lateral rays. This lack of stability allows for medial shift of the ray and hallux valgus formation. While researchers have shown some association with the cause of hallux valgus being related to the position of the distal articular cartilage of the first metatarsal and tendon imbalance of the great toe, the most common cause of deformity is related to the laxity of the first metatarsocunieform joint. With this laxity, there is a medial shift and relative elevatus of the first metatarsal as well as a medial shift of the great toe. Too often, this underlying instability is missed as an underlying cause and symptom of hallux valgus deformity. Callus formation or pain plantar to the second metatarsal, thickening of the second metatarsal shaft and dorsal spurring of the first metatarsal with exostosis of the first metatarsocunieform joint are all signs of possible first ray laxity. The single greatest positive factor for employing the Lapidus procedure is the added stability one can provide to the midfoot and medial column. This allows for better function of the peroneus longus tendon and retrograde stability of the rearfoot complex with a better shift of weight from the rearfoot to forefoot. How The Lapidus Allows More Intraoperative Flexibility A closing base wedge is a very difficult procedure to comprehend conceptually. It is difficult to perform well consistently, considering the triplane correction required for proper hallux valgus correction. While it is fairly easy to perform a wedge procedure and correct the intermetatarsal angle, it is far more difficult to correctly reduce the intermetatarsal angle, plantarflex the first metatarsal and correct possible frontal plane rotation of the ray with a wedge removal of bone. This subsequently results in a possible elevated ray, overcorrected angle and poor alignment. By performing the Lapidus with curettage and realignment, one can reduce the intermetatarsal angle, shift the first metatarsal plantar to correct elevatus and rotate the first metatarsal to correct frontal deformity. Although it is slightly more difficult to facilitate a frontal rotation and plantar shift with wedge correction Lapidus procedures, it is still possible. The Lapidus is also an excellent procedure as one can fine tune the correction under fluoroscopy, limiting the chance of over- or undercorrection prior to placing the fixation. Once one has performed a closing wedge osteotomy of the first metatarsal, it is very difficult to correct the alignment without breaking the hinge and/or further osteotomy of the bone. Addressing The Issue Of Large Intermetatarsal Angles Although one can correct a large intermetatarsal (IM) angle with a closing base wedge, if a closing wedge is required for correction of a large IM angle, there must be a severe hallux valgus. This may be due to the instability of the medial column. If this is the case, there may be a high chance of recurrence of the deformity in a young or very active person due to the extreme loads placed on the medial column.