Is The Miami Phalangeal Osteotomy A Viable Alternative To The Akin Osteotomy?

Author(s): 
Michael M. Cohen, DPM, FACFAS

Imagine that you were running late on your way to the hospital to attend to an urgent patient. You have a choice of two routes. One route is longer because it uses two streets, each with a traffic light, and no place to make a U-turn and change direction if the traffic is heavy. The shorter route is a straight shot but has no traffic lights with options for U-turns if necessary.

   Which route would you take?

   Now imagine you are in the operating room and need to finalize your bunionectomy with a phalangeal osteotomy. You have two available options. Option one involves resecting a medially based wedge (Akin osteotomy) with two converging bone cuts, often requiring you to feather the cuts to fit and align the osteotomies while making an effort to keep the lateral hinge intact. All the while, you realize that under- or overcorrection will be difficult, if not impossible, to correct.

   Alternately, you could employ your second option, the oblique proximal phalangeal osteotomy (aka the Miami phalangeal osteotomy) and perform a single through and through osteotomy. There would be no need to feather your bone cuts. You would also have the ability to dial in your correction without the need for additional osteotomies or shortening should you need to fine-tune your correction.

   Which procedure would you do? The pragmatic response appears quite obvious: the second one.

   There are dozens of metatarsal osteotomies described in the literature for the correction of the hallux valgus deformity. Yet since 1925, the Akin medially based closing wedge osteotomy has remained essentially the sole phalangeal osteotomy in the surgeon’s armamentarium for the correction of hallux valgus.1 The osteotomy is designed to correct an aberrant distal articular set angle or excessive hallux interphalangeal angle. In reality, surgeons use the procedure to create the illusion of a rectus toe and medialize soft tissue structures.

   Despite the procedure and its various modifications, the Akin osteotomy is not benign. The disadvantages and reported complications are real. Some of these include: instability with loss of the hinge; shortening of 3 to 5 mm; intraarticular fracture and degenerative joint disease (8 to 9 percent); plantar angulation with malunion (13 to 24 percent); nonunion when bone apposition is less than 50 percent; and difficulties with fixation. Additionally, the procedure often compromises the medial capsule periosteal tissue needed for soft tissue plication.2-4

   Another disadvantage of the Akin procedure is the possibility for under- and overcorrection. It would be difficult if not impossible to correct an over-exuberant wedge resection with little to no ability for intraoperative fine-tuning if needed.

A Closer Look At Key Advantages And Indications For The Miami Phalangeal Osteotomy

At the American College of Foot and Ankle Surgeons national conference in 2002, I introduced the oblique proximal phalangeal osteotomy and subsequently published on the technique in 2003.5 The study described a single through and through osteotomy directed from proximal dorsal to plantar distal.

   The procedure eliminates many of the problems experienced with the Akin osteotomy by offering several advantages. It is technically easy to perform, offers a stable construct that results in minimal to no shortening, does not violate the medial soft tissue structures and preserves them for capsulorrhaphy. The osteotomy produces two flat, broad surfaces of bone, reducing the chances of nonunion. Finally, the technique is highly conducive to rigid fixation and allows immediate weightbearing and range of motion. Moreover, the osteotomy is precisely adjustable by allowing the surgeon to dial in the correction without the need to feather or perform additional bone cuts.

   The indications for the Miami phalangeal osteotomy are identical to the Akin procedure. The Miami osteotomy also addresses the distal articular set and the hallux interphalangeal angles. I find it especially useful when addressing crossover or second toe impingement problems, and when correcting bunion deformities in patients with a pronated foot and a high metatarsal adductus component. In these patients, it is well recognized that lasting correction is a challenge despite a well-executed operation with proper intermetatarsal angle restoration. In this situation, both the Akin and Miami phalangeal osteotomies provide an enhanced cosmetic outcome, theoretically providing a longer lasting result.

   The Miami phalangeal osteotomy has additional inherent uses. It is an excellent procedure to use when addressing failed hallux valgus surgery requiring correction of angular malalignment of an Akin osteotomy. The procedure allows realignment of the phalanx without the need to shorten the phalanx further by extracting an additional wedge of bone. Other potential uses include the ability to slide the phalanx proximally as an adjunctive procedure to elevate the distal fragment when treating hallux limitus or distract distally to lengthen and plantarflex the phalanx if it has been shortened with a previous osteotomy.

A Step-By-Step Guide To The Surgical Technique

Through a medial or dorsomedial approach, reflect the capsule with minimal to no dissection over the medial phalanx. Perform all the proximal osteotomies. Direct attention to the base of the proximal phalanx and identify the dorsal phalangeal tubercle just distal and central to the articular surface. This represents the attachment of the extensor capsularis tendon.

   Using a saw, perform a straight through and through osteotomy at approximately 25 to 30 degrees to the longitudinal bisection. Aim for the tip of the toe and stay parallel to the nail plate. It is best to make the osteotomy as long as possible and at a gradual angle, exiting as distal as possible and just proximal to the interphalangeal joint. Rotate the toe medially and fixate the osteotomy provisionally with a K-wire (usually 0.062 inch) directed dorsal to plantar when the correction appears satisfactory.

   One may use intraoperative fluoroscopy to confirm the reduction. If the correction is inadequate, retract the K-wire and reinsert it after dialing in the proper correction. When you are satisfied with the correction, place a parallel drill guide over the K-wire and fixate the osteotomy with one or two mini fragment screws. The 0.062-inch K-wire hole makes a perfect sized drill hole for a 2.0 mm screw and one may use this for a second screw if necessary.

   However, be sure not to place the screw too proximal near the edge of the shelf to avoid fracturing through it. Countersinking will help avoid this problem, particularly if one is using a 2.7 mm screw. Use the intact periosteal capsular structures as this will allow you to perform a sound plication.

Examining The Efficacy Of The Miami Phalangeal Osteotomy

A study focused on 36 oblique proximal phalangeal osteotomies performed in 32 patients with an average age of 49.9 years.5 At a follow-up of three to 21 months, angular correction ranged from 7 to 22 degrees and the hallux interphalangeal angle was corrected to within 5 degrees of neutral. There were no nonunions or delayed unions, no hardware loosening and only one patient had a mild loss of correction. The time to achieve healing ranged from four to eight weeks. No bone callus or osteoarthritis occurred.

   At an average of 11 months follow-up, the total range of motion ranged from 82 to 87 degrees.5 All patients were ambulating at a mean of nine weeks in a tennis shoe. (I should note here that patients underwent proximal metatarsal osteotomies concurrently.) The average shortening was 1 mm (range 0 to 2 mm). There were no cases of extensor and flexor tendonitis. There were two radiographic overcorrections. Two cases of mild varus rotation of the hallux occurred (these were undetectable to the patient) due to an excessively steep osteotomy (>40 degrees).

In Conclusion

Studies indicate that phalangeal osteotomies are a useful addition to hallux valgus surgery.4-7 The Miami phalangeal osteotomy has provided consistently good outcomes and has proven to be an excellent alternative to the Akin osteotomy in the treatment of hallux valgus. At this time, our institution has performed approximately 200 osteotomies with very reliable results.

   The Miami phalangeal osteotomy offers several advantages, which include precise correction and minimal shortening. In addition, the osteotomy is a stable construct that is easily fixated. By preserving the medial capsule and ligaments, the technique lends itself to a sound plication. The procedure is useful in addressing the malaligned Akin osteotomy and as an adjunct in the treatment of hallux limitus while posing few potential complications.

   Dr. Cohen is the Chief of Podiatric Surgery for the Surgical Service at the Veterans Affairs Medical Center in Miami. He is a Fellow of the American College of Foot and Ankle Surgeons.

References

1. Akin OF. The treatment of hallux valgus: a new operative procedure and its results. Med Sentinel. 1925; 33:678-679.
2. Goldberg I, Bahar A, et al. Late results in the correction of hallux valgus deformity by basilar phalangeal osteotomy. J Bone Joint Surg. 1987; 69(1):64-67.
3. Frey C, Jahss M. The Akin procedure. Foot Ankle. 1991; 12(1):1-16.
4. Springer KR. The role of the Akin osteotomy for hallux abducto valgus, Clin Pod Med Surg. 1989; 6(1):115-131.
5. Cohen MM. The oblique proximal phalangel osteotomy in the correction of hallux valgus deformity. J Foot Ankle Surg. 2003; 42(5):282-9.
6. Mitchell L, Baxter D. A Chevron Akin double osteotomy for correction of hallux valgus. Foot Ankle. 1991; 12(1):7-14.
6. Barouch LS, Barouk P, Baudet B, Toullec E. The great toe proximal phalanx osteotomy: the final step of the bunionectomy. Foot Ankle Clin. 2005; 10(1):141-155.

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