Pertinent Insights On Proximal Bunionectomies
- Volume 25 - Issue 10 - October 2012
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After placing the screws, evaluate the foot for any intercuneiform/intermetatarsal instability. Surgeons commonly utilize a third screw, oriented from the proximal shaft of the first metatarsal to the base of the second metatarsal, to further stabilize the construct.
An adjunct to the procedure is the use of locking plate technology in addition to compression screws. This incorporates the additional compression needed to facilitate bony ankylosis with the stability of a locking plate construct. After obtaining appropriate reduction and position of the fusion site, fashion a locking plate to the dorsal medial aspect of the fusion site. One may employ a combination of locking and non-locking screws to ensure a strong plate to bone interface without prominence.
Finally, direct attention distal to the first MPJ, where resection of the dorsal medial eminence may be necessary to complete the procedure. Then close the incision in standard layered fashion. Dress the area and place the patient in a splint to facilitate initial non-weightbearing. Our postoperative course is protected partial weightbearing at four weeks, full weightbearing at six weeks in a controlled ankle motion (CAM) boot and conversion to a walking shoe at eight weeks.
A Closer Look At The Evidence
The popularity of the Lapidus procedure is highlighted by its ability to correct severe hallux abducto valgus and multi-planar instability. Although researchers first described this procedure many decades ago, the vast majority of outcome-based reports have been presented in the last 10 years.
Cohen and colleagues compared an isolated locking plate technique to isolated cross screw fixation and found the latter to be a superior construct.5 However, the authors did not investigate the combination of lag screw with locking plate fixation.
Scranton and co-workers evaluated the load to failure comparing single compression screw with a locking plate to a crossed screw configuration.6 In this cadaveric study, a higher load to failure rate occurred in the locking plate group.
Sorensen and colleagues took their report further, looking at fusion rates and time to fusion for their cohort.7 Patients underwent Lapidus fusion using a single lag screw and locking plate construct. The study authors found the average fusion time was 6.95 weeks with no delayed unions or nonunions in their patient population. Time to weightbearing was two weeks for all patients. The authors concluded that the stability of the lag screw with a medial locking plate construct allows for early weightbearing with no reduction in fusion rates.7
The benefit of the Lapidus procedure is evident and for proximal bunion deformities, we use it exclusively. Surgeons have made important advances with this procedure through consistent study and evaluation. These efforts have brought to light the complications and pitfalls of the procedure but most importantly, they have shown consistent and valid data to remedy these complications through further surgical advancements. Lastly, advancements in internal fixation paired with the evidence on stable constructs have given surgeons the confidence to advance their patients’ postoperative care more aggressively than in days past.
We recommend the following pearls. Employ the curettage technique with minimal bone resection to reduce shortening and dorsiflexion. Since the Lapidus procedure allows for correction in multiple planes, reserve the resection of the medial eminence for final osseous correction. Employ the “third” screw technique, medial plate fixation or intermediate cuneiform fixation to reduce first and second ray instability, and strengthen the construct.