Stability and fixation techniques in first metatarsal osteotomies.

Osteotomy of the first metatarsal is a common procedure for correction of hallucal disease. Metatarsals are unique in that they are the only long bones in the human body that support load perpendicular to their longitudinal axis during standing. Thus, osteotomy of the first metatarsal may be complicated by loss of fixation, resulting in nonunion or malunion. The authors review the forces that must be resisted by the osteotomy of the first metatarsal as postoperative weight bearing is initiated, and explore the principles of osteotomy geometry and different fixation techniques to maximize stability of the final construct and to minimize the risk of displacement.     

Proximal crescentic metatarsal osteotomy: the effect of saw blade orientation on first ray elevation

BACKGROUND: Moderate and severe hallux valgus deformities generally require a proximal metatarsal osteotomy to correct a widened intermetatarsal angle. Although excellent results have been reported using the proximal crescentic osteotomy, concerns have been raised about the incidence of postoperative dorsal malunion, which may lead to transfer lesions. The objectives of this paper were to evaluate the influence of saw blade angulation on the final position of the first metatarsal and to test a new technique used to ensure proper orientation of the osteotomy. METHODS: For part I of the study, 26 Sawbones specimens with hallux valgus deformities were corrected using a proximal crescentic osteotomy with the saw blade position incrementally rotated in the coronal plane. The sagittal change in the final position of the metatarsal was quantified radiographically and correlated to the saw blade orientation. For part II of the study, a Kirschner wire was placed in a vertical position into the medial cuneiform to serve as a guide for the crescentic saw blade in 13 cadaver feet with hallux valgus. Metatarsus primus elevatus was measured after surgical correction. RESULTS: Part I of the study demonstrated a highly linear relationship (R2=0.95) between first metatarsal elevation and the orientation of the saw blade. Every 10-degree of saw blade angulation resulted in a 2-mm change in the sagittal position of the first metatarsal. In part II of the study, the average change in metatarsus primus elevation for the 13 specimens after surgical correction of the hallux valgus deformity was only 1.1 mm (range -3.9 to +4.9 mm). Eleven of the 13 specimens had less than 2.5 mm of elevatus. CONCLUSION: Dorsal malunion of the first metatarsal after proximal crescentic osteotomy is a recognized complication. The final position of the hallux metatarsal is influenced by the coronal plane orientation of the saw. A new technique is described to aid the surgeon in proper alignment of the saw and help prevent excessive first ray elevation.     

Second metatarsal osteotomies for metatarsalgia: A robotic cadaveric study of the effect of osteotomy plane and metatarsal shortening on plantar pressure

Symptom relief of recalcitrant metatarsalgia can be achieved through surgical shortening of the affected metatarsal, thus decreasing plantar pressure. Theoretically an oblique metatarsal osteotomy can be oriented distal to proximal (DP) or proximal to distal (PD). We characterized the relationship between the amount of second metatarsal shortening, osteotomy plane, and plantar pressure. We hypothesized that the PD osteotomy is more effective in reducing metatarsal peak pressure and pressure time integral. We performed eight DP and eight PD second metatarsal osteotomies on eight pairs of cadaveric feet. A custom designed robotic gait simulator (RGS) generated dynamic in vitro simulations of gait. Second metatarsals were incrementally shortened, with three trials for each length. We calculated regression lines for peak pressure and pressure time integral vs. metatarsal shortening. Shortening the second metatarsal using either osteotomy significantly affected the metatarsal peak pressure and pressure time integral (first and third metatarsal increased, p < 0.01 and <0.05; second metatarsal decreased, p < 0.01). Changes in peak pressure (p = 0.0019) and pressure time integral (p = 0.0046) were more sensitive to second metatarsal shortening with the PD osteotomy than the DP osteotomy. The PD osteotomy plane reduces plantar pressure more effectively than the DP osteotomy plane. Published 2013 by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 32:385–393, 2014.     

Percutaneous sagittal plane closing wedge osteotomy of the first metatarsal

Osteotomy of the first metatarsal in the sagittal plane is useful in correction of numerous deformity of the foot. Plantarflexion osteotomy of the first metatarsal can be used to treat hallux rigidus, hallux limitus, forefoot varus in flatfoot deformity and iatrogenic metatarsus primus elevates. Dorsiflexion osteotomy of the first metatarsal is an important component in surgical correction of pes cavus. It is also indicated in recalcitrant diabetic neuropathic ulcers at the first metatarsal head. We described a minimally invasive technique of sagittal plane corrective osteotomy of the first metatarsal, which can be either a plantarflexion or dorsiflexion one.     

Planning tool for first metatarsal length in hallux valgus surgery

BackgroundThe precise planning of metatarsal (MT) I length in hallux valgus surgery is important. However, currently no tool exists which allows the surgeon to reliably predict this parameter.Methods30 virtual 3-dimensional hallux valgus surgeries were performed on varied deformation models based on cadaveric feet scans. The shortening of the first ray during distal metatarsal I osteotomy for different osteotomy angles were measured. An algebraic 2-dimensional calculation was done and compared to the results obtained from the 3-dimensional models.ResultsInadvertent shortening of the first metatarsal bone can be as much as 8 mm depending on the amount of intermetatarsal angle (IMA) correction and osteotomy angle. Comparison of the 3 dimensional simulations and the 2 dimensional model resulted in a very strong correlation (R > 0.99 p < 0.00001). Based on our findings an anterior pointing osteotomy of approximately 10° is necessary to restore the length in distal metatarsal I hallux valgus surgery.ConclusionA slight misdirection of the osteotomy plane in distal hallux valgus surgery may result in relevant unwanted alterations in first metatarsal bone length and triangulation by eye is insufficient in this complex geometrical situation without appropriate planning. The present study provides surgeons a practical tool to plan and control the change of first metatarsal length during hallux valgus procedure through exact orientation of the osteotomy angle. If no alteration of length is intended, it may be generalized that an anterior direction of the cut relative to the second metatarsal bone will preserve the length of the first metatarsal bone.     

Shortening of the first metatarsal as a complication of metatarsal osteotomies

There have been few reports of shortening of the first ray of the foot because of damage to the physis of the first metatarsal during the performance of metatarsal osteotomy for residual metatarsus adductus. In a retrospective study of twenty-seven feet in twenty patients who underwent this procedure, eight feet in seven patients were noted to have some degree of residual shortening of the first ray. This is an incidence of 30 per cent. The follow-up period after osteotomy ranged from two years to seven years and four months (average, four years). We could find no clear correlation between the occurrence of shortening and the patient's age at osteotomy, sex, or race, or the etiology of the adduction for which the osteotomy had been done. A clear correlation was found, however, with the surgical technique that had been employed. In two of the eight feet with a short first ray, the osteotomy had been done within the physis of the first metatarsal. In the other feet the procedure had employed an osteotomy site close to the physis or extensive periosteal dissection, or both. The results in our patients implicate subperiosteal dissection of the first metatarsal as an important, previously unreported cause of damage to the physis and of the resultant shortening. We recommend radiographic determination of the relationship of the osteotomy site to the physis before dissection is performed.     

Biomechanical consequences of adding plantar fascia release to metatarsal osteotomies: Changes in forefoot plantar pressures

Destruction of the normal metatarsal arch by a long metatarsal is often a cause for metatarsalgia. When surgery is warranted, distal oblique, or proximal dorsiflexion osteotomies of the long metatarsal bones are commonly used. The plantar fascia has anatomical connection to all metatarsal heads. There is controversial scientific evidence on the effect of plantar fascia release on forefoot biomechanics. In this cadaveric biomechanical study, we hypothesized that plantar fascia release would augment the plantar metatarsal pressure decreasing effects of two common second metatarsal osteotomy techniques. Six matched pairs of foot and ankle specimens were mounted on a pressure mat loading platform. Two randomly assigned surgery groups, which had received either distal oblique, or proximal dorsiflexion osteotomy of the second metatarsal, were evaluated before and after plantar fasciectomy. Specimens were loaded up to a ground reaction force of 400 N at varying Achilles tendon forces. Average pressures, peak pressures, and contact areas were analyzed. Supporting our hypothesis, average pressures under the second metatarsal during 600 N Achilles load were decreased by plantar fascia release following proximal osteotomy (p < 0.05). However contrary to our hypothesis, peak pressures under the second metatarsal were significantly increased by plantar fascia release following modified distal osteotomy, under multiple Achilles loading conditions (p < 0.05). Plantar fasciotomy should not be added to distal metatarsal osteotomy in the treatment of metatarsalgia. If proximal dorsiflexion osteotomy would be preferred, plantar fasciotomy should be approached cautiously not to disturb the forefoot biomechanics. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:800–804, 2017.

     

Percutaneous dorsal closing wedge osteotomy of the metatarsal neck in management of metatarsalgia

IntroductionMetatarsalgia can be caused by plantarflexion of a central metatarsal or discrepancies in the metatarsals’ length. Nonsurgical management is usually sufficient to achieve satisfactory results. For those recalcitrant cases, metatarsal osteotomy is needed to relieve the pain. We describe a technique of percutaneous dorsal closing wedge osteotomy of the metatarsal to manage the recalcitrant metatarsalgia. A case series was reviewed retrospectively.Materials and methodsFrom March 2010 to March 2013, percutaneous dorsal closing wedge osteotomy of the metatarsal neck has been performed in 33 patients. Thirty six feet with 63 metatarsals were operated on. Thirty two second metatarsals, 22 third metatarsals, 5 fourth metatarsals and 4 fifth metatarsals were operated on.ResultsAll the osteotomy sites healed up without any transverse plane deformity. The painful callosities subsided except in one operated metatarsal. Recurrence of painful callosities occurred in 2 operated metatarsals. Transfer metatarsalgia occurred in 2 feet. Floating toe deformity occurred in 2 operated rays. There was no nerve injury noted. Two patients had delayed wound healing with serous discharge and the wounds were eventually healed up with wound dressing.ConclusionPercutaneous dorsal closing wedge osteotomy of the metatarsal neck is an effective and safe surgical treatment of recalcitrant metatarsalgia.     

Plantar forefoot pressure changes after second metatarsal neck osteotomy

BACKGROUND: The aim of this study was to evaluate plantar pressure changes after second metatarsal neck osteotomy using the Weil technique. METHODS: Six below-knee cadaver specimens were used. Each specimen was held in a custom-built apparatus and loaded to 500 N for a period of 3 seconds. Using a computerized Musgrave pedobarograph, pressure measurements were made before and after osteotomy in both neutral and 45-degree heel rise positions. All osteotomies were made at an angle of approximately 20 degrees relative to the long axis of the metatarsal shaft. The metatarsal heads were displaced proximally by 5 mm and fixed with a single Kirschner wire. RESULTS: After osteotomy there was an average decrease in pressure beneath the second metatarsal from 70.6 to 45.1 kPa in neutral and from 813.0 to 281.4 kPa in heel rise, representing statistically significant (p < or = 0.05) decreases of 36% and 65%, respectively. There also were significant decreases beneath the third metatarsal in both neutral (39%) and heel rise (37%), and beneath the fourth metatarsal in neutral position (28%). A significant pressure increase occurred beneath the first metatarsal in neutral (23%). No significant pressure changes occurred under the fifth metatarsal in either position. CONCLUSION: Overall, our results indicated that the Weil metatarsal neck osteotomy is effective at offloading the second metatarsal head at neutral and heel rise positions.     

Metatarsal bars more effective than metatarsal pads in reducing impulse on the second metatarsal head

Background

The second metatarsal head is commonly involved in cases of metatarsalgia. As part of the conservative treatment, metatarsal bars and metatarsal pads are often prescribed.

Objective

To compare the effectiveness of metatarsal bars and metatarsal pads in reducing impulse on the second metatarsal head.

Method

Thirty-five healthy subjects were monitored with an insole scanning system during walking in four different conditions: (a) wearing shoes only, (b) shoes plus metatarsal pads and shoes plus metatarsal bars, placed either (c) perpendicular to the foot axis or (d) oblique to the foot axis. The impulse under the second metatarsal head was measured using the first condition as a control. Both feet were examined in each subject resulting in a total of 840 measurements.

Results

Both metatarsal bars and metatarsal pads were effective in reducing impulse when compared with the control (P < 0.01). Metatarsal bars were found to be more effective in reducing impulse as compared to the metatarsal pads (P < 0.01), and the oblique position of the bars was more effective than the perpendicular one (P < 0.01).

Conclusions

The greatest reduction of impulse on the second metatarsal head in healthy subjects is achieved with the use of metatarsal bars in an oblique position.     

Three-dimensional computer analysis of the modified Ludloff osteotomy

BACKGROUND: The Ludloff first metatarsal osteotomy is used to correct the increased 1-2 intermetatarsal angle associated with hallux valgus deformity. We studied the spatial geometry of this osteotomy to determine the ideal parameters of the osteotomy saw cut and its rotation to give an optimal correction. METHODS: Three-dimensional computer modeling software was used to perform a virtual Ludloff osteotomy of the first metatarsal. Different geometric parameters of the osteotomy were studied. The osteotomy was rotated in virtual space and the geometric changes occurring in the virtual bone were then measured by the software. RESULTS: The optimal Ludloff osteotomy started at the dorsum of the first metatarsal base at the first tarsometatarsal joint and extended distally and plantarly to a point just proximal to the sesamoid articulation. A tilt of 10 degrees in the coronal plane of the osteotomy was necessary to limit first metatarsal head elevation. The best axis of rotation was within 5 mm of the proximal end of the osteotomy. CONCLUSIONS: The optimal geometric parameters of a modified Ludloff osteotomy limited first metatarsal shortening, elevation, and sagittal plane rotational malalignment that may occur with the use of this osteotomy.     

Avascular necrosis of the hallux metatarsal head

Avascular necrosis of the first metatarsal head is rare. Although idiopathic cases have been reported, AVN of the first metatarsal head is usually iatrogenic following surgical correction of hallux valgus using a distal metatarsal osteotomy with or without lateral soft tissue release. A thorough understanding of the delicate vascular anatomy of the first metatarsal head is essential when surgery is considered. Careful operative technique permits a safe combination of distal osteotomy and lateral soft tissue release. Because the intraosseous blood supply is completely disrupted with distal metatarsal osteotomy, excessive capsular release and saw blade penetration into the lateral capsular vessels must be avoided. Among the thousands of reported distal metatarsal osteotomies performed using a variety of technique modifications of the original procedure described by Austin, the prevalence of AVN is low. Undoubtedly, the first metatarsal head has an excellent capacity to accommodate to changes in its blood supply. Although radiographic changes are frequently observed in the metatarsal head following a distal metatarsal osteotomy with or without lateral release, rarely do these changes progress to symptomatic AVN. These transient radiographic findings probably represent an adjustment period as the metatarsal head recovers from vascular compromise. Not only is AVN of the first metatarsal rare, but it is rare for it to be symptomatic. Many more cases that are never identified may exist. Management of symptomatic AVN of the first metatarsal head has not been standardized because of the infrequency of this condition. Anecdotal experience suggests that simple activity and shoe modifications may suffice; however, joint debridement and metatarsal head decompression may prove beneficial as they have in the management of other joints more commonly afflicted with AVN. Finally, severe head collapse may be salvaged with MTP joint arthrodesis. In the event that a substantial amount of avascular bone must be removed, consideration can be given to bone block distraction arthrodesis to avoid transfer metatarsalgia.     

Retrospective study of closing wedge osteotomy complications at the base of the first metatarsal with bone screw fixation

The authors describe the surgical technique for bone screw fixation of closing wedge osteotomies of the first metatarsal. They found that the angle of the bone screw should be perpendicular or almost perpendicular to the osteotomy or fracture. They also found age and time of weightbearing to be important factors.     

Distal first metatarsal chevron osteotomy

The distal chevron osteotomy is a popular, reliable, effective procedure for correcting hallux valgus deformity and bunions. The procedure has been refined to produce and maintain satisfactory correction and repair. Significant modifications to the original procedure include alteration of the bone cuts and more thoughtful soft tissue releases to improve correction of sesamoid positioning. The most significant improvement involves a change in the osteotomy plane and angle, combined with internal fixation to maintain the correction. Finally, the sharp edge of the superior medial corner of the metatarsal head, identified as a source of excess pressure in shoewear, can be removed and beveled to a smooth rounded surface.     

Comparative mechanical testing of different geometric designs of distal first metatarsal osteotomies

BACKGROUND: The mechanical behavior of a newly described distal metatarsal osteotomy design in the shape of a reversed "L" was compared with the modified chevron and scarf osteotomies. METHODS: Experiments were performed using full-sized Sawbone models (Sawbones Europe AB, Malm?, Sweden) of the first ray. Three groups consisting of 10 scarf, 10 modified chevron, and 10 reversed L osteotomies were investigated. All distal fragments were displaced 5 mm laterally without angulation. The proximal fragment of each specimen was embedded in an epoxy resin cylinder and positioned at 15 degrees inclination to the ground. The distal fragment was loaded by a dorsally directed vertical force which was applied at the sesamoid location under the metatarsal head. Load and displacement at failure, work to failure, site of failure and contact areas were recorded for each osteotomy. RESULTS: Similar testing results were obtained in the reversed "L" and chevron osteotomies, while the scarf osteotomy needed almost 5 times less work to failure. In nine of 10 reversed "L" osteotomies and in all scarf osteotomies, the site of failure was at the proximal screw insertion site. The contact areas averaged 163 mm(2) for the reversed "L," 116 mm(2) for the chevron, and 270 mm(2) for the scarf osteotomy. CONCLUSIONS: The reversed L osteotomy is a promising design combining the advantages of both the chevron and scarf osteotomies. Further investigations need to be performed to confirm its clinical utility.     

Blood supply to the first metatarsal head and vessels at risk with a chevron osteotomy

BACKGROUND: Chevron osteotomy, a commonly performed procedure for the treatment of hallux valgus, results in osteonecrosis of the first metatarsal head in 0% to 20% of cases. The aim of this study was to map out the arrangement of the vascular supply to the first metatarsal head and its relationship to the limbs of the chevron osteotomy. METHODS: Ten cadaveric lower limbs were injected with an India ink-latex mixture, and the feet were dissected to assess the blood supply to the first metatarsal head. The dissection was carried out by tracing the branches of the dorsalis pedis and posterior tibial vessels. A distal chevron osteotomy was mapped, with the limbs of the osteotomy set at an angle of 60 degrees from the geometric center of the first metatarsal head. The relationship of the limbs of the osteotomy to the blood vessels was recorded. RESULTS: The first metatarsal head was found to be supplied by branches from the first dorsal metatarsal, first plantar metatarsal, and medial plantar arteries. The first dorsal metatarsal artery was the dominant vessel among the three arteries in eight specimens. All of the vessels formed a plexus at the plantar-lateral aspect of the metatarsal neck, just proximal to the capsular attachment, with a varying number of branches from the plexus then entering the metatarsal head. The plantar limb of the proposed chevron cuts exited through this plexus of vessels in all specimens. Contrary to the widely held view, only minor vascular branches could be found entering the dorsal aspect of the neck. CONCLUSIONS: The identification of the plantar-lateral corner of the metatarsal neck as the major site of vascular ingress into the first metatarsal head suggests that constructing the chevron osteotomy with a long plantar limb exiting well proximal to the capsular attachment may decrease the postoperative prevalence of osteonecrosis of the first metatarsal head.     

Plantar pressure distribution in hallux valgus feet after a first metatarsal proximal crescentic osteotomy with a lesser metatarsal proximal shortening osteotomy

BackgroundPlantar pressure distribution after the first metatarsal proximal crescentic osteotomy (FMPCO) with lesser metatarsal proximal shortening osteotomy (LMPSO) for hallux valgus with metatarsalgia has not been previously described.MethodsThe pre- (Pre) and postoperative (Post) groups comprised of 18 patients who underwent unilateral FMPCO with LMPSO; fifteen healthy volunteers constituted the control (C) group. For each of the 10 regions, peak pressure (Peak-P), maximum force (Max-F), contact time (Con-T), contact area (Con-A), and force-time integral (FTI) were measured.ResultsThe mean Peak-P of the second metatarsal head was significantly lower in the Post group than the Pre group. The mean Peak-P, Max-F, Con-T, and FTI were not significantly different between the Post and C groups. The mean Con-A was significantly lower in the Post group than the C group.ConclusionFMPCO with LMPSO may improve the plantar pressure of the central forefoot comparable to healthy subjects.     

Metatarsalgia: distal metatarsal osteotomies

Metatarsalgia is a common pathologic entity. It refers to pain at the MTP joints. Pain in the foot unrelated to the MTP joints (such as Morton’s neuroma) must be distinguished from those disorders, which lead to abnormal pressure distribution, reactive calluses, and pain. Initial treatment options for metatarsalgia include modifications of shoe wear, metatarsal pads, and custom-made orthoses. If conservative treatment fails, operative reconstructive procedures in terms of metatarsal osteotomies should be considered. Lesser metatarsal osteotomy is an effective and well-accepted method for the management of metatarsalgia. The main purpose of these osteotomies is to decrease prominence of the symptomatic metatarsal head. The distal metatarsal oblique osteotomy (Weil osteotomy) with its modification represents the best evaluated distal metatarsal osteotomy in terms of outcome studies and biomechanical analysis. The role of the Weil osteotomy in metatarsalgia owing to a subluxed or dislocated MTP joint is to bring the metatarsal head proximal to the callus and to provide axial decompression of the toe to correct the deformity contributing to metatarsalgia.     

Distal metatarsal osteotomy for hallux valgus

Distal osteotomy of the first metatarsal with a step lateral displacement has been used in the treatment of 34 feet with hallux valgus.Stability of the osteotomy is achieved by a dorsomedial capsulorrhaphy. Suturing through drilled holes or internal fixation were not necessary. One case was complicated by dorsal tilt of the head of the metatarsal bone and required revision.     

Opening base wedge osteotomy of the first metatarsal utilizing rigid external fixation

The authors describe their operative approach to metatarsus primus adductus deformity when present in conjunction with a congenitally short first metatarsal. Hallux abducto valgus correction in this clinical setting has traditionally advocated use of a crescentic or opening wedge osteotomy in order to prevent further shortening of the first metatarsal. Fixation of opening base wedge osteotomies has been fraught with problems in the past, with possibilities for displacement or eventual loss of initial correction. The authors have found the mini-Hoffmann external fixation device useful for this purpose.