A Closer Look At An Emerging Fixation Option For The Akin Osteotomy
- Volume 23 - Issue 7 - July 2010
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Proceed to utilize the appropriate double-holed EasyClip SI template/drill guide by centering it dorsally over and ensuring a perpendicular orientation to the hallux proximal phalanx osteotomy site. Use a 2.0 mm drill to pre-drill the pilot holes for the EasyClip SI compression device. After completing each drill hole, use a 2 mm post to maintain and identify each drill hole. Use a depth gauge to measure the length of staple needed and load the appropriately sized staple on the provided forceps. We have most commonly used the EZM 10-10-10 staple, which has a 10 mm staple width and 10 mm staple leg length, for the hallux proximal phalanx.
Use the forceps to preload and diverge the prongs of the staple to allow for insertion. Then insert it into the pre-drilled holes in the hallux with one prong distal and one proximal to the osteotomy site. When you have released the staple from the forceps, the elastic property of the staple allows the prongs to converge to achieve compression across the osteotomy site. Use a tamp to ensure the staple sits flush to the bone.
At this time, one may utilize a C-arm to assess alignment and fixation if desired. Otherwise, surgeons may opt for radiographic evaluation of fixation postoperatively.
Irrigate the wound with sterile normal saline and perform capsular, subcutaneous and skin closure according to your preference. The postoperative course includes immediate weightbearing as tolerated in a surgical shoe. Then one may transition the patient to a sneaker in approximately four weeks.
Facilitating Good Compression, Rigid Fixation And Lower Risks Of Complications
While a limited number of articles have described the complications associated with the Akin procedure, the more commonly discussed and encountered complications include: plantar angulation at the osteotomy site; fracture at the lateral cortical hinge; shortening; under/over correction; and delayed/nonunion.11,13,14 A delayed or nonunion as well as recurrence can result from bone apposition of less than 50 percent. One can maintain bone apposition by diligently performing an accurate osteotomy as well as internal fixation.
The EasyClip SI compression device offers excellent compression and rigid fixation. It offers constant compressive forces that optimize bone apposition and reduce the risk of delayed and nonunion. This staple gives the benefits of screw fixation with relative technical ease of application. Additionally, the EasyClip SI compression device is sleek enough that should the lateral hinge be violated or fracture, application of a second staple would be possible. When using screw fixation, if the lateral cortical hinge is compromised, it can be technically challenging to achieve a second point of fixation.
Another advantage of using this fixation device is the minimal dissection of the soft tissue required for its insertion. One can obtain access to the bone from the dorsum as opposed to the medial aspect. This reduces the need for overzealous retraction and exposure. This subsequently reduces the risks of postoperative complications such as tissue necrosis, wound dehiscence, edema and infection. The dorsal approach also decreases the risk of directly compromising the neurovascular bundle.
Utilizing this method of fixation also affords the surgeon the option to perform a traditional transverse osteotomy of the proximal phalanx. We have found that the transverse osteotomy adequately corrects the deformity with less removal of bone, thus decreasing the shortening of the hallux as long as the cortical hinge remains intact. Optimal orientation of screw fixation should achieve maximal compression across the osteotomy site and increased bone apposition is perpendicular to the osteotomy. Screw fixation technique would be nearly impossible with a transverse Akin (which led to its obliquely oriented variation). Also, due to the nature of the staple, there is less chance for rotation of the bone as opposed to a traditional screw.