Youngswick-Austin procedure: the effect of plantar arm orientation on metatarsal head displacement.

The Youngswick-Austin metatarsal head procedure was developed to allow for correction of a mildly elevated metatarsal head and/or to shorten an abnormally long first metatarsal. However, it was difficult to accurately and consistently predict the amount of plantar metatarsal head displacement utilizing this modification of the Austin procedure. This study demonstrated, through the use of preoperative templates and a mathematical formula, that the angle of the plantar arm relative to the weightbearing surface of the foot is what dictates the amount of plantar metatarsal head displacement. The authors divide the angle of the chevron osteotomy into a dorsal and plantar arm angle and demonstrate that the larger the angle of the plantar arm, the greater one can plantarly displace the metatarsal head.     

Amputation of the great toe. A clinical and biomechanical study

Clinical and biomechanical observations were made on otherwise normal feet in ten patients, who had had amputations for pollicization of the great toe. Measureable changes were demonstrated in the patients' gait pattern and in force plate data. The center of pressure was noted to shift from beneath the second metatarsal head on the normal side to beneath the third metatarsal head on the amputated side. The velocity of movement of the center of pressure slowed significantly in the metatarsal head region of the operated side, which secondarily resulted in an increased loading of the metatarsal region. The progression of the center of pressure was noted to be beneath the third metatarsal head region on the involved side, instead of progressing medially and distally toward the first web space. Clinically, the operated foot demonstrated slight thickening beneath the second and third metatarsal heads but no significant abnormal callus formation developed. The patients' shoes all showed increased lateral wear on the amputated side. From a functional standpoint, the patients had little or no disability from loss of the hallux.     

First metatarsal head shape in juvenile hallux abducto valgus.

A round first metatarsal head has been implicated as a predisposing factor in hallux abducto valgus. The shape of one hundred first metatarsal heads was analyzed on 50 weightbearing dorsoplantar x-rays of 10-year-old children with a hallux abductus angle in excess of 15 degrees and osteophytic thickening of the first metatarsophalangeal joint. The metatarsals were subjectively described as either round or square. A measurement technique was then devised to quantify in millimeters the difference between the two types. Using chi-square analysis, a very strong statistical association (p less than 0.001) was found between the subjective assessment and the objective measurement. A weak relationship was found between the metatarsal head shape and the degree of hallux abducto valgus (HAV) (r = -0.294). While the trend of this correlation is consistent with accepted wisdom, that is, the squarer the metatarsal head the less the hallux abducto valgus, the association is not strong enough to scientifically confirm it. This finding along with the presence of so many square metatarsal heads in children with advanced HAV indicates that assessment of metatarsal head shape has little place in the scientific assessment of first metatarsophalangeal joint pathology.     

The Reverdin-Isham procedure for the correction of hallux abducto valgus. A distal metatarsal osteotomy procedure

The Reverdin-Isham Procedure is a distal metatarsal osteotomy procedure that has stood the test of time and has revolutionized the correction of simple to severe hallux abducto valgus deformities. This procedure, a modification of the classic Reverdin bunionectomy, modifies the osteotomy cut of Reverdin by performing a medial wedge osteotomy through the head of the first metatarsal. In this modification, the osteotomy is performed at an oblique angle from dorsal distal to plantar proximal through the head of the first metatarsal, preserving the entire articular surface of the first metatarsal head. The result of this osteotomy places the articular surface of the first metatarsal into alignment with the shaft of the first metatarsal, thereby correcting the structural deformity of hallux abducto valgus at the first MPJ. This modification, using the advances of minimal incision surgery, is a procedure that is highly successful, permits immediate ambulation, causes minimal disability, allows early return to productive activities, and is cost effective.     

Hallux sesamoid bones. Anatomical observations with special reference to osteoarthritis and hallux valgus

Summary The normal characteristics of the hallux sesamoid bones were studied in 200 toes (100 dissections and 100 radiographs from patients with hallux valgus), and pathological changes were recorded. Normally each sesamoid articulated with a separate groove on the plantar surface of the first metatarsal head. A bony ridge on the head separated these grooves.Bipartite sesamoids were found in 4% of the toes. Osteoarthritic changes manifested by deformity, irregularity, lipping, cysts in the sesamoids and in the heads of the first metatarsal and erosions in the articular surfaces were present in 32% of the dissected toes. Fusion of the sesamoids was found in 6%. Ankylosis between the sesamoids and the head of the metatarsal was observed in 4%.In the toes affected by hallux valgus the sesamoids, together with the plantar pad and the tendon of the flexor hallucis brevis, were displaced laterally to a variable degree. In severe deformities the lateral sesamoid was dislocated lateral to the first metatarsal head and the medial sesamoid occupied the groove originally corresponding to the lateral sesamoid, while the metatarsal ridge separating the two sesamoids tended to disappear. Osteoarthritis of the metatarsophalangeal joint frequently accompanied hallux valgus.     

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.     

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.     

Effect of metatarsal pad placement on plantar pressure in people with diabetes mellitus and peripheral neuropathy

BACKGROUND: Standard prevention and treatment strategies to decrease peak plantar pressure include a total contact insert with a metatarsal pad, but no clear guidelines exist to determine optimal placement of the pad with respect to the metatarsal head. The purpose of this study was to determine the effect of metatarsal pad location on peak plantar pressure in subjects with diabetes mellitus and peripheral neuropathy. METHODS: Twenty subjects with diabetes mellitus, peripheral neuropathy, and a history of forefoot plantar ulcers were studied (12 men and eight women, mean age=57+/-9 years). CT determined the position of the metatarsal pad relative to metatarsal head and peak plantar pressures were measured on subjects in three footwear conditions: extra-depth shoes and a 1) total contact insert, 2) total contact insert and a proximal metatarsal pad, and 3) total contact insert and a distal metatarsal pad. The change in peak plantar pressure between shoe conditions was plotted and compared to metatarsal pad position relative to the second metatarsal head. RESULTS: Compared to the total contact insert, all metatarsal pad placements between 6.1 mm to 10.6 mm proximal to the metatarsal head line resulted in a pressure reduction (average reduction=32+/-16%). Metatarsal pad placements between 1.8 mm distal and 6.1 mm proximal and between 10.6 mm proximal and 16.8 mm proximal to the metatarsal head line resulted in variable peak plantar pressure reduction (average reduction=16+/-21%). Peak plantar pressure increased when the metatarsal pad was located more than 1.8 mm distal to the metatarsal head line. CONCLUSIONS: Consistent peak plantar pressure reduction occurred when the metatarsal pad in this study was located between 6 to 11 mm proximal to the metatarsal head line. Pressure reduction lessened as the metatarsal pad moved outside of this range and actually increased if the pad was located too distal of this range. Computational models are needed to help predict optimal location of metatarsal pad with a variety of sizes, shapes, and material properties.     

Ultrasonographic measurement of the mechanical properties of the sole under the metatarsal heads.

The sole under the metatarsal heads functions as a shock absorber during walking and running. The mechanical properties of the sole provide the primary defense against the development of metatarsalgia and foot ulceration. However, limited information about these properties has been documented. In this study, we used ultrasonography to evaluate the mechanical properties, including unloaded thickness, compressibility index, elastic modulus, and energy dissipation ratio, of the sole in 20 healthy subjects. The unloaded thickness decreased progressively from the first to the fifth metatarsal heads, with values of 1.50, 1.36, 1.25, 1.14, and 1.04 cm. The sole under the first metatarsal head had the greatest values for the compressibility index and elastic modulus (55.9% and 1.39 kg/cm2), and the sole under the third metatarsal head had the smallest values (50.8% and 1.23 kg/cm2). The sole under the fifth metatarsal head had the greatest energy dissipation ratio (33.7%), followed by that under the third, second, first, and fourth metatarsal heads. Multivariate adjusted linear regression showed that the unloaded thickness, compressibility index, and elastic modulus values increased significantly with age and body weight (p < 0.05) and that the energy dissipation ratio increased significantly with body weight (p < 0.05)     

Treatment of Freiberg's disease. A new operative technique

A method of treating Freiberg's disease of the metatarsal head by shortening the metatarsal bone is described. This operation has been performed in 15 patients (16 feet). Excellent relief of pain was obtained, although most patients had persistent stiffness of the metatarsophalangeal joint.     

Metatarsal Head Resection in the Rheumatoid Foot: 5-Year Follow-Up With and Without Resection of the First Metatarsal Head

Twenty-nine patients (45 feet) who underwent metatarsal head resections for rheumatoid forefoot deformities were reviewed retrospectively at a mean follow-up of 6.57 years (range, 5-9.3 years). Resections were confined to the lesser metatarsal heads in 16 feet because of a lack of involvement in the first metatarsal head. In the remaining 29 feet, all metatarsal heads were resected. A questionnaire was provided to assess subjective outcomes. Thirty-three feet (73.3%) had no pain or only mild pain, 5 feet (11%) had moderate pain, and 7 (15.5%) had severe pain. Among the 29 feet with panmetatarsal head resections, 5 (17%) required revision of metatarsal stumps at an average follow-up of 55.2 months (range, 17-84 months; standard deviation, 26.88). Among the 16 feet with only lesser metatarsal head resections, 7 (43.75%) required subsequent first metatarsal head resections at an average follow-up period of 33.14 months (range, 13-56 months; standard deviation, 16.54). In conclusion, metatarsal head resection is a simple procedure that gives long-term pain relief in over two thirds of the patients who have rheumatoid forefoot deformities. A high rate of recurrence of pain and subsequent resection of first metatarsal head is noted if it is not resected primarily. We recommend a low threshold for the inclusion of some form of primary reconstruction of the first metatarsophalangeal joint when resection arthroplasty is performed on the lesser toes.     

Percutaneous Bunionette Correction Without Fixation: Clinical Results and Radiographic Evaluations Including Rotation of Metatarsal Head and Sagittal Angle Change of Fifth Metatarsal

Bunionette deformities have been treated as an analog of hallux valgus, and the surgical techniques are similar. Most commonly anteroposterior image is evaluated pre- and postoperatively. To our knowledge, only one study has evaluated changes on the lateral radiograph and no study has evaluated changes in rotation of the fifth metatarsal head postoperatively. In percutaneous bunionette correction using a burr for osteotomy, shortening of the fifth metatarsal and elevation of the metatarsal head are inevitable. Without fixation, there is also a possibility of rotational change to the metatarsal head. We measured parameters on anteroposterior and lateral weightbearing radiographs in 18 feet pre- and postoperatively. Rotation of the fifth metatarsal head was graded according to the medial tubercle location. We also evaluated angular change of the fifth metatarsal on weightbearing lateral radiographs. Percutaneous bunionette correction without fixation could achieve satisfactory clinical and radiographic results, with less complication, when compared with previously published outcomes of open and percutaneous surgery with fixation. In this surgical method, bunionette is corrected in 3 dimensions. To our knowledge, this is the first study to evaluate rotation of the metatarsal head and change in the sagittal angle of the fifth metatarsal after bunionette correction.     

Correction of metatarsus primus varus with the Chevron metatarsal osteotomy. An analysis of corrective factors

A trigonometric evaluation of the amount of correction of metatarsus primus varus obtainable via lateral displacement of the first metatarsal head in a Chevron osteotomy technique revealed that approximately 1 degree of correction may be obtained for each millimeter of lateral shift. This calculated correction was correlated with the actual correction obtained in ten feet. Narrowing of the metatarsal head associated with removal of the medial eminence was an additional corrective factor.     

Bunionette.

The bunionette, or tailor's bunion, is a painful osseous prominence on the lateral aspect of the head of the fifth metatarsal. This prominence occurs in many individuals but seldom causes symptoms. Orthotic devices may be useful if a symptomatic bunionette results from excessive pronation of the subtalar joint. Operative management to decrease the width of the foot and the osseous prominence is indicated when nonoperative treatment can no longer control symptoms and when the patient has special demands, particularly in sports. A proximal osteotomy is able to correct most deformities. A distal osteotomy is recommended if medial translation of the head for one-third of the width of the metatarsal shaft produces a normal fourth-fifth intermetatarsal angle.     

Brachymetatarsia. IV: A different surgical approach

A review of the surgical alternatives available for the correction of brachymetatarsia is presented with an introduction of a different surgical approach. This involves the transplantation of a portion of the fifth metatarsal and head to the short fourth metatarsal. The results of three cases are presented with a discussion of the indications, technique, and complications.     

Comparison of plantar pressure, clinical, and radiographic changes of the forefoot after biplanar Austin osteotomy and triplanar Boc osteotomy in patients with mild hallux valgus

BACKGROUND: Boc's modification of the Austin procedure is a triplane distal osteotomy that achieves shortening and plantarflexion of the first metatarsal with a lateral translation of the metatarsal head. The clinical results and influence of the Austin and Boc osteotomies on plantar pressure have been compared retrospectively. MATERIALS AND METHODS: The patients were divided into two groups: 30 Austin and 30 Boc osteotomies were performed with a mean followup of 37 (range, 29 to 56) months. RESULTS: Sixty patients with mild hallux valgus deformities and central metatarsalgia, took part in the study. Pressure measurements were performed with a Diagnostic Support system footplate. The average postoperative American Orthopaedic Foot and Ankle Society score of the Austin group was 81.9 and 86.4 for the Boc group. The pressure distributions under the fourth and fifth metatarsal head were comparable in both groups (p>0.05). The Austin group showed decreased load bearing under the hallux and the first metatarsal head (p<0.01), consistent with a persistent overloading of the second and third metatarsal head (p>0.05). The Boc group showed decreased weightbearing under the hallux with better load distribution beneath the second and the third metatarsal head (p<0.05). Correlation of the American Orthopaedic Foot and Ankle Society scores and pressure variables confirmed a significant negative correlation with altered hallux and central metatarsal head loading (p<0.01). CONCLUSION: The Boc triplane osteotomy seems to restore more physiologic loading of the forefoot in comparison to the Austin procedure, reducing the incidence of painful callus under the second and third metatarsal head.     

第二跖骨头缺血性坏死的显微外科治疗

为探索治疗成人第二跖骨头缺血性坏死的新术式，应用带血管蒂跖骨瓣逆行移位植骨治疗４例，效果满意。随访１年６个月以上者２例，Ｘ线片示第二跖骨头呈圆形，密度均匀，跖趾关节功能良好。认为，带血管蒂跖骨瓣逆行移位植骨可为缺血坏死跖骨头带入可靠的血供和各种成骨因素，并可达到清理关节腔，骨内减压和凿除骨赘，修整跖骨头等目的     

Modifications of the Weil osteotomy have no effect on plantar pressure

Previous studies have shown that increasing angulation of the Weil osteotomy produces greater plantar translation of the metatarsal head. Modifications have been proposed to reduce plantar translation. However, there is no evidence that the increased plantar translation with a Weil osteotomy is clinically significant or that these modifications are required. Ten lower extremities consisting of five matched pairs were used to evaluate whether different configurations of the Weil osteotomy altered plantar pressure in a dynamic cadaver model. For each pair, an oblique Weil osteotomy with a 5-mm shift was done on one side and a standard (parallel) Weil osteotomy with a 5-mm shift was done on the matched foot. A 4-mm slice resection and a metatarsal head resection then were done sequentially. Plantar pressures were measured with cyclic loading to 700 N at a frequency of 1 Hz with an F-scan in-shoe sensor on the intact specimens and after each intervention. Increased plantar translation of the metatarsal head with a more oblique Weil osteotomy did not significantly increase plantar pressure, and the 4-mm slice resection did not significantly unload the metatarsal head. Only complete metatarsal head resection significantly unloaded the metatarsal head.     

The arterial supply of the lesser metatarsal heads: a vascular injection study in human cadavers

The possibility of avascular changes of the metatarsal heads following forefoot surgery has been previously documented. The aim of this study was to investigate the arterial supply of the lesser metatarsal heads with regard to osteotomies of these bones. We used epoxy resin injections and a modified Spalteholz technique in human cadaveric specimens to demonstrate the intraosseous and extraosseous blood supply of the lesser metatarsals. The metatarsal heads had two arterial sources: 1. The dorsal metatarsal arteries, which arose from the dorsalis pedis artery, and 2. The plantar metatarsal arteries, which are branches of the posterior tibial artery. These two vessels typically anastomosed at two sites about the metatarsal heads, forming a vascular ring and provided an extensive extraosseous arterial network around the metatarsal heads. Small arterial branches of this network run distally on the metatarsal cortex to enter the bone of the metatarsal head. The nutrient arteries traversed the cortex of the metaphysis close to the capsular and ligamentous insertions to provide multiple branches for the supply of the subchondral bone. Extensive capsular stripping during metatarsal head osteotomies results in damage to the medial and lateral head vessels.     

Isolated slipped-retroverted osteochondral fracture of second metatarsal head

Although metatarsal fractures are common, isolated intraarticular metatarsal head fractures are rare, and retroversion of the fracture segment is even rarer. Herein, a retroverted fracture of the second metatarsal head, which happened with a direct trauma from jumping from a height, was discussed with treatment options and finally a simple surgical trick was advised. There are only a few cases of isolated osteochondral and retroverted fractures of the metatarsal head in literature. The following is a rare case report of such an injury in a 19-year-old male.