A Guide To Performing An Effective Weil Osteotomy

Pages: 20 - 25
Author(s): 
Emily Pepyne, DPM, MPH, and Harry Schneider, DPM

The Weil osteotomy, a distal oblique osteotomy of the metatarsal head, is a commonly performed procedure that can address transverse and sagittal plane pathologies of the metatarsophalangeal joint (MPJ). While this procedure is very popular in the podiatric community, it is not without pitfalls and complications. We will discuss “pearls” of the Weil osteotomy and surgical tips to improve patient satisfaction and clinical outcomes, and prevent complications.

The most common indication to perform Weil osteotomy is metatarsalgia due to metatarsal overloading. Knowing the exact reason for the metatarsal overload is of utmost importance when determining appropriate procedure selection. Failure to address the root cause of the pain will almost certainly lead to inferior outcomes. There are several types of biomechanical overload but we can separate them into two primary categories: static and propulsive.1

In static overloading, the affected metatarsal is positioned more plantar in comparison to the adjacent metatarsals. Ground reactive forces cause friction and pain to the metatarsals. We commonly encounter this when there is hyperkeratotic tissue buildup underneath the metatarsal head.1 First ray elevatus and first ray insufficiency can indirectly lead to plantar positioning of the lesser metatarsals.
With propulsive overloading, the metatarsal is elongated in relation to the parabola. Subtle length differences cause increased pressure on the elongated metatarsal when the patient is transitioning to the propulsive phase of gait. Weil compared this to “pole vaulting” off the elongated metatarsal.1 Propulsive metatarsal overload can also be caused by iatrogenic shortening of an adjacent metatarsal, which can lead to relative lengthening of the affected metatarsal, and subsequent overloading and pain. Elongated metatarsals are often prone to plantar plate injury.1

Avoiding Pitfalls With The Weil Osteotomy

The traditionally published technique is to start the osteotomy in the dorsal articular surface of the metatarsal head. The orientation of the cut is from dorsal-distal to proximal-plantar along the metatarsal shaft, angulated 30 degrees, with an attempt to be parallel to the weightbearing surface.2

Unfortunately, it is well documented that the Weil osteotomy is fraught with potential complications such as “floating toe.” Creating the osteotomy at an angle that is too oblique, over-shortening (>3 mm) or starting the osteotomy too proximally may lead to plantar displacement of the capital fragment when shortening the metatarsal. Plantar displacement can alter the rotational axis of the metatarsophalangeal joint and lead to floating toe syndrome.4

Researchers believe floating toe is due to a dorsal displacement of the interosseous muscle relative to the MPJ’s axis of rotation due to shortening and plantarflexion of the metatarsal.5 The dorsal displacement of the muscles results in the loss of the flexion effect and permits the pull of the extensor tendon to dorsiflex the toe.

Surgeons can make a cut that is too oblique in a Weil osteotomy. The left photo shows the effect of this oblique cut. When shortening the metatarsal, this causes plantarflexion of the metatarsal head.

Another commonly encountered pitfall is malrotation of the metatarsal head when shortening and fixating the osteotomy. Medial translation of the metatarsal head on the shaft can occur with screw fixation. This results in misalignment of the metatarsal head at the metatarsophalangeal joint.

The final possible pitfall we present is failure of internal fixation. This can occur when one is performing a concomitant hammertoe correction and advancing the digital fixation wire across the metatarsophalangeal joint. Crossing the MPJ may cause unnecessary trauma to the articular cartilage of the metatarsal head. It may also create a stress riser at the site of the Weil osteotomy, leading to fracture of the metatarsal head.  

A 54-year-old female had a Weil osteotomy with screw fixation and second digit arthrodesis with K-wire fixation spanning the metatarsophalangeal joint. The patient was subsequently non-adherent with non-weightbearing status. Non-adherence coupled with the positioning of the K-wire created a lever arm, which resulted in failure of the osteotomy just proximal to the screw fixation (see right photos). This patient required revisional surgery with plating across the osteotomy site.

How To Prevent Floating Toe Complications

Numerous modifications have emerged to prevent floating toe. Our facility has employed the use of a “Weil with a Wafer” technique.  

Weil modification one. The first cut is a traditional distal cut, angled at least 30 degrees, without penetrating through the plantar aspect of the metatarsal shaft.

For the second cut, reorient the saw distally and parallel to the initial cut. Penetrate through both cortices on the second cut. This creates two parallel cuts, resulting in a “wafer” (see left photo). Return to the first cut and finish the cut through the distal cortex before removing the aforementioned wafer. Another variation of this technique is to simply fashion two saw blades on the saw. This allows for a wider osteotomy cut.

Perform metatarsal shortening and fixation, but the metatarsal should not appear plantarflexed.                         

Weil modification two. The left half of the right photo shows the traditional Weil osteotomy cut, which is parallel to the weightbearing surface. The right half of the right photo shows that when one decompresses this elongated metatarsal osteotomy, it does not cause as much plantarflexion as the previous cut. Therefore, the more parallel cut more accurately maintains the joint axis of rotation. Using the mantra “it can never be too long” helps reduce the risk of floating toe syndrome.                 

Finally, as we discussed previously, another potential complication is rotation of the metatarsal head in the transverse plane when attempting to shorten and decompress the MPJ. In order to prevent this, place a cross-shaped grid marking on the metatarsal head in both the vertical and horizontal axis (see left photo). The horizontal axis marks the starting location of the osteotomy and ensures that the cut is parallel. After shortening, lining up the vertical axis ensures that there is no angulation or rotation of the head when fixating the osteotomy.

In Conclusion

The Weil osteotomy is a tried-and-true procedure but it is not without potential complications such as “floating toe” and metatarsal head malalignment. Ensuring the osteotomy angle is parallel with the weightbearing surface or considering the “Weil with a Wafer” technique will help reduce the prevalence of floating toe. In addition, creating a grid type marking will help ensure capital fragment positioning remains stable in both the vertical and horizontal planes. By considering these simple and easy pearls, the practitioner may be able to improve surgical outcomes and patient satisfaction.

Dr. Pepyne is the Chief Resident at Cambridge Health Alliance PMSR/RRA Residency Program.  

Dr. Schneider is the Program Director of the Cambridge Health Alliance Podiatric Medicine and Surgery PMSR/RRA residency program. He is a Fellow of the American College of Foot and Ankle Surgeons and Assistant Professor of Surgery at Harvard Medical School.

References

  1. DeHeer P, Weil L Jr. Point–Counterpoint: Is the Weil osteotomy overused by DPMs? Podiatry Today. 2010; 23(6):56–62.
  2. Downey M, Spizzirri S. Chap 20. Transverse plane digital deformities. In Southerland JT, Boberg JS, Downey MS, et al (eds.): McGlamry’s Comprehensive Textbook of Foot and Ankle Surgery. Fourth Edition. Wolters-Kluwer, Philadelphia, 2012, Chapter 20, pp. 206-232.
  3. Melamed EA, Schon LC, Myerson MS, Parks BG. Two modifications of the Weil osteotomy: analysis on sawbone models. Foot Ankle Int. 2002; 23(5):400-05.
  4. Perera A, Helguera-Mendoza O, Myerson M. Can modification of the Weil osteotomy reduce the risk of dorsiflexion contracture? A biomechanical cadaveric analysis. Presented at the American Orthopedic Foot and Ankle Society, 2012.
  5. Trnka H, Nyska M, Parks BG, Myerson MS. Dorsiflexion contracture after the Weil osteotomy: results of cadaver study and 3D analysis. Foot Ankle Int. 2001; 22(1):47-51.

 

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