Pertinent Insights On Lesser Metatarsal Osteotomies

Acknowledging the challenges in treating lesser metatarsal pathologies, these authors discuss the relevant pathomechanics, review keys to appropriate procedure selection and provide a thorough review of the literature.

Disorders involving the lesser metatarsals are among the most difficult to treat as outcomes are often quite unpredictable for both conservative and surgical interventions. Given this issue that we face as treating physicians, we must have a thorough appreciation of the pathomechanics contributing to the various lesser metatarsal pathologies.^1-6

Conditions such as metatarsalgia can have many origins and contributing factors such as biomechanics, traumatic events and genetic predispositions. In order to provide the best outcomes for our patients, it is necessary to consider the whole picture and not focus singularly on the metatarsal itself. We must couple clinical and radiographic findings with the patient’s history to best address the deformity.^1-5 Similarly, treatment may require addressing more than just the metatarsal itself as there may be compounding factors which, if we do not address them, may predispose the patient to a poor outcome and recurrence of symptoms.^1-5

Accordingly, let us take a closer look at the various clinical and radiographic findings related to lesser metatarsal pathology, specifically metatarsalgia, and review the vast array of lesser metatarsal osteotomies designed to address this pathology. It is important to note that we will not specifically focus on lesser metatarsal osteotomies related to tailor’s bunions, brachymetatarsia or metatarsus adductus as we feel these subjects are worthy of separate distinction.

Current Diagnostic Pointers

Obtaining a thorough history and physical is of utmost importance to best identify the etiology of the patient’s pain and deformity. Patients may report pain that is more diffuse or global to the forefoot, or perhaps pain that is isolated to a single metatarsal. They may present with an isolated plantar keratosis. Those complaints, which are of acute onset, may lead one to believe a traumatic event led to the development of discomfort whereas a slower onset of discomfort that has progressed over a period of time would be more consistent with a biomechanical origin.^1-4

It is critical to perform a full biomechanical evaluation, including weightbearing and gait exams of these patients, not only to assess their complaints related to the metatarsal but also to evaluate for any concomitant deformities that are contributing to or exacerbating the metatarsal pain. For example, ankle equinus, cavus or planus foot types, hammertoe deformity, hypermobility of the first ray, a short first ray, first ray elevatus, or fat pad atrophy may all lead to metatarsal pain.^1-4,7-9

Evaluation of the patient’s shoegear can help one gain a better appreciation of the patient’s foot type and gait. Pedobarographic studies may prove useful as well to correlate with the clinical findings.
Metatarsal pain may have an iatrogenic origin as well. A common scenario that one may encounter is a patient developing metatarsal pain after a bunionectomy in which there was excessive shortening of the first ray, altering the load mechanics of the forefoot.¹⁰ Similarly, if the patient has had a lesser metatarsal procedure that alters the metatarsal parabola and again changes the load mechanics of the forefoot, transfer metatarsalgia may develop. Given the many factors that may be causing the patient’s discomfort, it is important not to narrow one’s focus to treating only the affected metatarsal but to properly address all contributing factors to minimize the patient’s likelihood of recurrence.

Radiographic evaluation should complement the clinical and gait evaluation. Prior to obtaining X-rays, it may be helpful to attach a lesion marker to the patient’s foot to help correlate the clinical and radiographic findings. Several points to consider on a dorsoplantar film include the metatarsal parabola, any specific signs of trauma or remodeling to the lesser metatarsals, degenerative changes at the metatarsophalangeal joints (MPJs), digital deformities, anatomic variants, the presence of foreign bodies and angular relationships. Typically, the normal anatomic parabola is 2>1=3>4>5.^1,2,7 If there is any variation to this, for example an excessively long or short metatarsal, an abnormal loading pattern may arise, producing the patient’s symptoms.

From a traumatic standpoint, other than an occult fracture, one may observe periosteal thickening, a change in radiodensity or fragmentation. Digital deformities in either the transverse or sagittal plane may produce an abnormal retrograde force on the corresponding metatarsal.^1-3 One should also note if there are any anatomic variants such as accessory sesamoids that may cause pain at the level of the MPJs, although this is relatively uncommon.

Similarly, on a lateral radiograph, one should evaluate for digital deformities, the declination of the metatarsals, etc. A sesamoid axial view may also prove helpful to evaluate for the presence of accessory sesamoids, prominence of the metatarsal head plantar condyles and soft tissue density. It is worth mentioning that a sesamoid axial view cannot evaluate the elevational relationships of the metatarsals as the positioning device and view both alter the true anatomic relationship.⁷ In all views, note any previously performed surgical procedures and how the outcome has impacted the patient. Pursue advanced imaging if radiographs are inconclusive.^1,2

Keys To Conservative Care And Surgical Treatment

Conservative treatment options such as immobilization, palliative lesion debridement, offloading, injections, medication or physical therapy, orthotics, and shoegear modifications may be successful for some patients while many others require definitive surgical intervention to address the metatarsal deformity.^7,9 It is important that the treating physician thoroughly explain the condition and various treatment modalities to patients, and ensure that they have a full understanding of the implications of each, especially in regard to the potential complications or recurrence following surgery.¹

In addition to selecting the proper surgical procedure for each patient, surgeons need to be thorough in their preoperative planning, taking into account factors such as incision placement and the neurovascular supply to the forefoot.^1,11

The main goals of surgical management of the lesser metatarsal-related complaints include pain and deformity reduction, which one may approach with proper digital and joint alignment, preservation of capsule tendon balance, and restoration/preservation of the parabola.⁷ Again, performing a metatarsal osteotomy alone often does not achieve these goals but surgeons can achieve success by performing this procedure in conjunction with correction of digital deformities and hallux abducto valgus deformity, and the use of postoperative orthotics. In fact, treatment of lesser metatarsal-related complaints may not involve surgical intervention specific to the lesser metatarsals. Mann and colleagues discovered that correcting the hallux abducto valgus deformity alone led to resolution of painful calluses in 63 percent of their patients.¹²

Authors have advocated multiple osteotomies focused on addressing lesser metatarsal deformities and pain. These osteotomies can effectively decompress the metatarsophalangeal joint, shorten or lengthen the metatarsal, and dorsiflex or plantarflex the metatarsal.¹ The osteotomy of choice is specific to the patient’s pathology and the surgeon often performs it in concert with other procedures. Several considerations are specific to each osteotomy, such as position, angulation, fixation and weightbearing. Many of these go hand in hand. For example, a midshaft osteotomy is subject to greater loading as the gait cycle progresses, and therefore would require a longer period of non-weightbearing and a more stable fixation construct.¹

Selecting The Most Effective Osteotomy Technique

Now let us review some of the traditional lesser metatarsal osteotomies and identify pertinent insights relative to each to assist the surgeon in achieving the optimal outcome for the patient.  
From a historical perspective, Meisenbach reported on the first lesser metatarsal osteotomy in 1916. This was a transverse, midshaft, non-fixated osteotomy with dorsal translation of the capital fragment to alleviate pain secondary to submetatarsal head hyperkeratosis.¹³  

In the years that followed, authors described numerous other surgical procedures, including Mau’s resection of a trapezoidal wedge from the proximal metatarsal (1940), McKeever’s telescopic shortening osteotomy (1952), DuVries’ plantar condylectomy (1953), Giannestras’ midshaft step-cut osteotomy (1956) and Kelikian’s metatarsal head resection with syndactylization of digits (1961), just to name a few.^14-18 While there have been multiple modifications to these procedures over the years, it is important to note that all of the original authors described these procedures without fixation. Researchers believed that the capital fragment would find its own level via ground reaction forces. One of the first lesser metatarsal procedures described with fixation was the dorsal closing base wedge osteotomy that Sgarlato discussed in 1971.¹⁹  

In 1973, Graver was the first to advocate a metaphyseal V-shaped osteotomy with a proximally oriented apex to prevent translation in the transverse plane.²⁰ Jacoby reported a similar osteotomy that year but with the apex oriented distally.²¹ Many found this to be more advantageous as it did not violate the joint capsule, allowing for greater stability. In 1996, Lauf and Weinraub modified the V-type osteotomy, which consisted of an asymmetric arm to allow for fixation.²² Sullivan and O’Donnell originally described a dorsal distal to plantar proximal oblique osteotomy without fixation in 1975.²³ Helal advocated a dorsal proximal to plantar distal osteotomy that same year.²⁴ In 1987, Reese and Scoffield presented a double osteotomy in which one makes two parallel and oblique cuts distal dorsal to proximal lateral with subsequent removal of the bone and fixation.²⁵ While the authors originally described this procedure at the level of the metatarsal neck, Spence and coworkers described a similar procedure at the proximal aspect of the metatarsal in which one removes but does not fixate a cylindrical wedge of bone.²⁶  

In the present day, the Weil osteotomy has become one of the more favored osteotomies as it is relatively minimally invasive, technically easy to perform, stable, and has documented good outcomes with high patient satisfaction.¹ The surgical technique includes a dorsal MPJ incision followed by capsulotomy, taking care to respect the neurovascular bundles and extensor tendons. Some advocate for placement of the capsulotomy on the medial or lateral aspect of the extensor tendon based on the side of greatest contracture.¹ Then one would perform capsular dissection to fully expose and evaluate the metatarsal head. Using a bone saw, the surgeon creates an intra-articular osteotomy, beginning approximately 2 mm from the dorsal cartilage margin and orienting the osteotomy from distal dorsal to proximal plantar.¹ One should make the osteotomy as parallel to the weightbearing surface as possible while being mindful not to invade the shaft of the metatarsal.

Once the osteotomy is complete, the capital fragment will translate proximally into its corrected position. Evaluate the desired position and fixate it in typical fashion, although some may choose to let the osteotomy heal without fixation. Fixation options typically include a single or double screw construct.¹ Once the definitive fixation is stable, resect the dorsal overhanging bone margin so as not to limit dorsiflexion. One should close the operative site in layers so as to minimize scar tissue formation and prevent contracture. Postoperative bandaging with the digit in a plantarflexed attitude is crucial to maintaining the correction.

Many authors have investigated outcomes related to lesser metatarsal surgery to better elucidate outcomes and complications. It is important to note, however, that outcomes specific to lesser metatarsal osteotomies alone are difficult to evaluate as more often than not, surgeons perform these procedures in conjunction with other corrections involving the digits or first ray.^8,9

In a 1998 study, Pontious and colleagues examined the efficacy of the V-osteotomy for plantar keratoses and evaluated if the use of fixation yielded a better outcome with fewer complications.⁷ The retrospective study on 40 procedures in 29 patients consisted of patients with plantar keratoses related to the second, third and fourth metatarsals. The patients all had a V-osteotomy. Surgeons performed digital, bunion and/or lesion excision procedures concomitantly in some cases. Of the 40 osteotomies, 15 did not have fixation. For 25 procedures, surgeons used fixation with either 0.062 or 0.045 Kirschner wires. The fixation was intact for an average of 4.8 weeks. Both groups had approximately 2 mm of shortening. While rates of recurrence (10 percent), transfer lesions (42.5 percent; 52 percent fixated and 26.7 percent non-fixated), lack of purchase (25 percent), and dehiscence (12.5 percent) were comparable in both groups, MPJ subluxation was only present in the non-fixated group (13 percent). Consolidation time in the fixated group (10 to 12 weeks) was significantly shorter in comparison to the non-fixated group (22 weeks).⁷

Overall, the authors concluded that the V-osteotomy showed limited success in treating plantar keratoses and that the use of fixation did not yield a more predictable result outside of shortening consolidation time.⁷

Kitaoka and Patzer also performed a study examining the outcomes of 24 chevron osteotomies (21 feet in 19 patients), specifying a 45-degree angle with a distal apex.⁹ One dorsally displaces the capital fragment 2 to 3 mm, impacts the fragment, and fixates proximally to distally with a Kirschner wire. Patients were immobile in a surgical shoe for five to six weeks with subsequent wire removal at three weeks. Similar to the Pontious study, patients had an average of 2.6 mm of shortening. Union occurred in all cases and at the four-year follow-up, only two patients had required revision. Based on a 70-point clinical outcome scale, the authors noted good results in 16 feet, fair results in two feet and poor results in three feet. The authors’ use of fixation in this study was guided by the previously reported higher rates of malunion without fixation use. These authors concluded that a distal chevron osteotomy yielded success for most patients.

Trnka and colleagues retrospectively reviewed the outcomes of 114 feet (96 patients) who had a Helal-type osteotomy for the treatment of metatarsalgia.¹⁰ The authors assessed if the clinical outcome was affected by patient age, follow-up or correction of bunion deformity (previous or simultaneous). Sixty-one percent of patients had an excellent or good outcome based on survey results. While age or the number of osteotomies performed did not impact outcome, the time following surgery and performance of a Keller arthroplasty procedure, prior to or simultaneously with a Helal osteotomy, negatively impacted results. A high incidence of transfer lesions was present.

Analyzing weightbearing patterns, the authors found an increase in loading under the operated metatarsal in 38 patients.¹⁰ Seven asymptomatic and one symptomatic non-union occurred along with one case of avascular necrosis. The authors attributed the avascular necrosis to placing the osteotomy too distally, an important point to make with regard to surgical planning. The authors felt as though this osteotomy did not produce predictable long-term outcomes.

Idusuyi and coworkers also reported on a Helal-type osteotomy but surgeons performed this in isolation on one metatarsal without any concomitant procedures.⁸ They noted similarly disappointing results with four of 23 feet requiring revision and over half of the patients reporting continued pain, two-thirds noting limitations in activity, and three-quarters of the patients having post-op shoegear limitations.
Galluch and colleagues reported on segmental midshaft metatarsal osteotomies fixated with a plate and screw construct.27 Transfer lesions were present in five of 95 patients and non-union occurred in one patient. The non-union resolved following the removal of hardware. Overall, the authors reported a 99.2 percent union rate, although they did not specify a timeframe.

Again, specific to midshaft osteotomies, DeSandis and colleagues examined union rates following a segmental shortening osteotomy.²⁸ Of 91 osteotomies, 29.7 percent were healed by three months and 75.8 percent healed by six months. At the six-month mark, 24.2 percent were not healed and thus classified as non-unions. Sixteen of the non-unions went on to heal progressively by 12.9 months for a final union rate of 93.4 percent. These results supported the authors’ hypothesis that more time is required to heal a midshaft osteotomy and that this procedure would be associated with a higher rate of delayed and non-unions. The authors attributed this to the nature and location of the osteotomy as it applies to the vascular anatomy of the metatarsal.

In Giannestras’ original study, 40 patients had a proximal step-cut osteotomy.¹⁷ Each arm of the osteotomy was 0.5 inches long, resulting in overall shortening of 0.5 inches. Ten percent of the patients developed a non-union while approximately 92 percent reported good to excellent results.

Kennedy and Deland reported on a modification of Coughlin and Mann’s diaphyseal oblique osteotomy.²⁹ Instead of central placement of the osteotomy, surgeons made the osteotomy slightly off midline to allow for easier fixation. These authors reported pain relief in 31 of 32 patients with union occurring in a mean of 10 weeks. Minor complications included one case of digit numbness, three cases of digital dorsiflexion contracture and one plantar digital callus. Authors reported no non-unions although they pointed out the healing time is longer in comparison to a distal procedure.

Sclamberg and Lorenz advocated a proximal V osteotomy with a proximal apex and 60 degree angle with the plantar cortex left intact.³⁰ One then creates a second V osteotomy, converging plantarly so as to remove a 3 to 4 mm wedge of bone. Subsequently, one violates the hinge and applies plantar pressure to shift the metatarsal dorsally, although the authors originally described this without fixation. All 41 patients included in their study had resolution of symptoms, no recurrence of plantar lesions and no major complications.

What You Should Know About Complications Of Lesser Metatarsal Osteotomies

Known complications of lesser metatarsal osteotomies include recurrence, transfer metatarsalgia, transfer lesions, non-union and over-shortening, which can lead to a floating toe deformity. Many of these complications can arise secondary to poor pre-op clinical evaluation and overreliance on radiographic findings. Failure to identify the true etiology leads to inappropriate procedure selection, resulting in a poor outcome for the patient. Again, multiple procedures addressing pathology on multiple levels may be required.¹¹

Published rates of floating toe deformity following Weil osteotomy range from 15 to 50 percent.¹ Surgeons may employ several techniques to help prevent this complication, including lengthening the extensor tendon, tightening the plantar capsule or pinning the digit across the MPJ. While a viable option to maintain digital position, introducing a wire across the joint and osteotomy may compromise the osteotomy and damage the cartilaginous joint surface.

Stiffness at the MPJ level is also a reported negative outcome of distal metatarsal osteotomies, which may result from exposure of the joint via excessive capsular dissection. This may be related to incision placement, length and closure techniques.¹¹ An arthrotomy, with or without an osteotomy, may free adhesions and return motion to the joint.

Symptomatic non-unions and deviation of the metatarsal often require revision with autogenous bone grafts and fixation.¹¹ With respect to delayed/non-unions, one must consider that the initial procedure has compromised the vascular supply to the metatarsal. Non-union rates in proximal osteotomies are reportedly as high as 76 percent.⁵

Hardware failure may also lead to complications requiring revisional surgery.³¹ Regardless of the outcome, one should attempt conservative treatment prior to revisional surgery as a second procedure may carry more risk and greater chances for complications than the first. Revisional techniques as we have outlined above can range from removal of hardware, grafting, repeat or multiple osteotomies, and even partial resection of the metatarsal. The surgeon must ensure the patient’s expectations are realistic in regard to the potential outcome.

In addition to the procedure specific shortcomings leading to complications, also consider the patient’s medical history. Patients with conditions such as diabetes and rheumatoid arthritis, or those who smoke are often predisposed to higher complication rates. This may involve increased incidence of dehiscence, non-healing, etc.³¹ Counsel patients appropriately so they can become optimized to experience the best outcome for the initial or revisional procedure.

In Summary

Treatment of lesser metatarsal related complaints requiring metatarsal osteotomies is something that one must approach carefully. Thorough clinical and radiographic evaluations are paramount to addressing the true etiology of the complaint. Always attempt conservative treatment first as lesser metatarsal osteotomies do not always have predictable results and can lead to complications that may be more symptomatic than the original condition. Patient education is crucial to ensure they understand the complex nature of their condition and the risks associated with surgical intervention.

If surgical intervention is necessary, proper procedure selection and preoperative planning are essential to achieving the best outcome for the patient. While different schools of thought on procedures, fixation and postoperative weightbearing exist, decisions should be specific to the patient. Much of the research to date does not provide clarity as to which procedure is best or a standard protocol for treatment. Future investigations are necessary to better evaluate the various osteotomies for lesser metatarsals and their outcomes so we may improve the postoperative outcomes for our patients.

Dr. Sansosti is the Chief Resident in the Temple University Hospital Podiatric Surgical Residency Program in Philadelphia.   

Dr. Pontious is a Clinical Professor and the Chair of the Department of Podiatric Surgery at Temple University School of Podiatric Medicine.

References

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27.     Galluch DB, Bohay DR, Anderson JG. Midshaft metatarsal segmental osteotomy with open reduction and internal fixation. Foot Ankle Int. 2007; 28(2):169-174.
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For further reading, see “Lesser Metatarsalgia: Are Lesser Metatarsal Osteotomies Necessary?” in the February 2013 issue of Podiatry Today or “Keys To Treating Proximal Fifth Metatarsal Fractures” in the February 2016 issue.