Minimally invasive surgical techniques are an alternative with potential advantages in the treatment of forefoot deformities.
Several surgical techniques have been described for the treatment of hallux valgus and lesser toe deformities.1-4 However, lack of agreement exists regarding which technique is the most efficacious.
Minimally invasive techniques have become increasingly popular in orthopedics. The application of these concepts in hallux valgus has been questioned in the past, in part due to the lack of scientific validation. However, recent studies have shown satisfactory results using these techniques.5-7
This article describes the minimally invasive techniques we use at the Italian Hospital of Buenos Aires and their indications in the treatment of hallux valgus and lesser digital deformities. All techniques are performed as outpatient procedures under ankle or popliteal block with the patient supine and the operative foot positioned off the end of the table.8 Fluoroscopy is useful to monitor the performance of some of the steps.
The Bösch technique is used to treat mild to moderate hallux valgus with an intermetatarsal angle of 10° to 20° and a distal metatarsal articular angle <10°.
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Figure 1: A 2-mm incision is made in the medial side of the great toe, approximately 5 mm plantar to the proximal edge of the nail. Figure 2: A second incision is made at the distal metaphysis of the first metatarsal, equidistant between the dorsal and plantar aspects of the bone. Figure 3: A 2-mm K-wire is inserted in retrograde form from the first to the second incision.
A 2-mm incision is made in the medial side of the great toe, approximately 5 mm plantar to the proximal edge of the nail (Figure 1). The wire entrance may be located dorsally when plantar metatarsal head displacement is desired, and plantarly if dorsal metatarsal head displacement is chosen. A second incision is made at the subcapital region of the first metatarsal, equidistant between the dorsal and plantar aspects of the bone (Figure 2). A 2-mm Kirschner wire is inserted retrograde from the first to the second incision (Figure 3). The K-wire must be placed subcutaneously and extraperiosteally to perform the metatarsal head displacement at the osteotomy site.
In the proximal incision, the periosteum is detached dorsally and plantarly with a small elevator, preserving its continuity to protect the soft tissues during the osteotomy.
The osteotomy is made in the first metatarsal subcapital region under fluoroscopic control, using an end cutting burr Shannon 44 (Miltex Instrument Co Inc, York, Pa). First, a pilot hole is made from medial to lateral. Using the hole as a guide, the bone cutter is swept around the dorsal and plantar cortex, trying to maintain the same angle proximally and distally (Figure 4). The osteotomy is performed perpendicular to the metatarsal shaft in the sagittal plane. In the frontal plane, the mediolateral obliquity of the osteotomy can be varied to shorten or lengthen the first metatarsal according to the preoperative plan. Furthermore, the metatarsal head can be rotated in the axial plane to correct rotational components of the deformity. Once the osteotomy is finished, mobility at the osteotomy site is checked under fluoroscopy.
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Figure 4: Intraoperative (A) and fluoroscopic (B) images of the osteotomy.
Next, a bent grooved guide is placed through the proximal incision into the proximal metatarsal bone fragment. The K-wire tip is placed in the concavity of the guide (Figure 5). Using the guide and K-wire as a lever, the metatarsal head lateral displacement and rotation is achieved and maintained during the wire progression into the medullary canal. While holding the hallux in a varus position, the wire is driven with smooth blows of the mallet to the base of the metatarsal. Fluoroscopy is used to confirm the lateral displacement of the head, and overlap of the proximal and distal fragments. The probe is taken out and the wire is cut, leaving 1 cm outside the skin. The medial step-off at the osteotomy site is evaluated and, if prominent, is resected percutaneously with the burr through the proximal incision. The skin around the proximal incision is freed up and is closed with Vicryl rapide 4.0 (Johnson & Johnson Intl, Brussels, Belgium).
When marked sesamoid subluxation is present, a distal lateral release is useful, but it is always performed at the end of the procedure since ligamentotaxis drives the correction of the distal fragment inclination.
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Figure 5: Intraoperative (A) and fluoroscopic (B) images. A bent, grooved probe is placed through the proximal incision in the proximal metatarsal bone fragment. Next, the K-wire is progressed until it reaches the probe concavity.
A bandage is placed to maintain the varus overcorrection of the hallux. The patient is encouraged to walk with full weight bearing on postoperative day one with a postoperative shoe.
The wire is kept in place for one month with weekly bandage changes. The wire then is removed and replaced by a bandage in varus with an interdigital kidney-shaped pad for two weeks. At six weeks, patients are encouraged to walk with regular shoes.
Exostectomy is used to treat mild hallux valgus with an intermetatarsal angle <12°.
A 2-mm incision is made in the plantar medial edge of the metatarsal immediately proximal to the eminence. Using a sharp elevator, the capsule is elevated (Figure 6). Using a burr, the eminence is removed to obtain a regular surface, taking care not to contact the joint. It is important to copiously irrigate the area (usually performed with a syringe and a 18° needle) since intra-articular debris can generate joint stiffness.
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Figure 6: Intraoperative (A) and fluoroscopic (B) images of the exostectomy.
Akin osteotomy is used to correct hallux interphalangeous.
A 2-mm incision is made using a medial approach over the proximal phalanx metaphysis. Detachment of the periosteum is performed with a small elevator dorsally and plantarly. The osteotomy is performed with the cutting burr under fluoroscopy control, preserving the lateral cortex of the phalanx. A pilot hole is made in the medial cortex and then sweep the burr plantar and dorsally without cutting the lateral cortex. Closed reduction is performed and checked by interposing the small elevator. No fixation is used. The great toe is bandaged in a forced varus position to maintain the correction.
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Figure 7: Extensor tendon tenotomy. Figure 8: Flexor tendon tenotomy.
The incision is made over the dorsal lateral first articular metatarsopahangeal joint. A single-edge scalpel is introduced in the articular space from dorsal to plantar. The blade is oriented laterally to cut the capsule and the adductor tendon, usually assisted by medial deviation of the toe.
Lesser Toe Deformities
Flexible claw/hammer toes can be treating with percutaneous tenotomies (extensor and flexor tendons). Extensor tenotomy is performed through a pari-tendinous dorsal incision. The tendon is identified by sliding the scalpel around its dorsal and plantar surfaces. The scalpel is placed beneath the tendon and the tenotomy is performed from plantar to dorsal moving down the toe, taking care to not injure the dorsal skin (Figure 7). Flexor tenotomy is made through a plantar incision at the base of the proximal phalanx (Figure 8). The toe must be put into dorsiflexion to shift the neurovascular bundle dorsally in a safer position. The cut should be at the level of the cortex to avoid damaging the neurovascular bundle.
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Figure 9: Preoperative (A) and postoperative (B) clinical appearance and preoperative (C) and postoperative (D) radiographs of a 52-year-old patient with a 17° intermetatarsal angle.
If nonflexible deformity exists, additional procedures can be performed as needed for correction. Plantar capsulotomy of the proximal interphalangeal joint can be performed through a 1-cm incision on the medial surface of the joint. A lateral capsulotomy is made with a single-edge scalpel following the curvature of the condylar surface to its plantar aspect. With the cutting edge of the scalpel placed in the plantar position, joint extension is performed carrying the plantar aspect of the capsule to the scalpel edge. The orientation of the articular surfaces should be considered when the scalpel is introduced in the joint to facilitate this technique.
If the toe persists in a dorsiflexion position, a dorsal metatarsophalangeal joint capsulotomy can be made. The articular space is located and, through an incision like that used for extensor tenotomy, capsulotomy can be performed.
A bandage is placed putting the metatarsophalangeal joint in plantar flexion and the proximal interphalangeal joint in dorsiflexion.
If it is impossible to achieve proper alignment of the toe, an open proximal interphalangeal joint arthroplasty is performed.
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Figure 10: Preoperative (A) and postoperative (B) clinical appearance and preoperative (C) and postoperative (D) radiographs of a 52-year-old patient with a 22° intermetatarsal angle.
Previously, surgical procedures have been described for the treatment of hallux valgus.1-4 No strong scientific evidence exists to determine the optimal technique to correct this deformity.
The popularity of minimally invasive techniques for the treatment of hallux valgus in recent years is consistent with recent studies that have shown satisfactory results.5-7 Our preliminary results with the techniques described in this article have been satisfactory and are under evaluation (Figures 9 and 10).
Bösch et al5 first performed this technique in 1984. In a study of 114 patients with long-term follow-up, they demonstrated satisfactory correction of the intermetatarsal and metatarsophalangeal angles with no complications of hallux varus, pseudoarthrosis, or osteonecrosis of the metatarsal head.
Magnan et al7 reported on 118 patients with an average follow-up of 36 months, with good clinical results (91%) and a low recurrence rate (2.5%). The average angular correction obtained was 5° and 7.5° for the intermetatarsal and metatarsophalangeal angle, respectively.7
One advantage of this technique is the short operating time required. This is particularly important in cases that require several surgical procedures to realign the forefoot. As with other percutaneous techniques, the Bösch technique decreases postoperative discomfort and, therefore, immediate weight bearing, improvement in postoperative metatarsophalangeal joint motion, and fewer local complications. Another advantage of this technique is that fixation is achieved with a K-wire without requiring additional implants, thereby reducing cost and facilitating removal.
The preliminary observations we made confirm these advantages, and we noted excellent sesamoid alignment with predictable healing of the osteotomy, even in cases with poor contact between bone fragments.
Disadvantages of our technique are the long learning curve and the lack of predictability of head displacement. The poor tolerance of the K-wire by some patients can result in early implant removal, although there was no loss of correction observed in these patients.
The use of our techniques in the deformities of the lesser toes has the same potential advantages: minimal soft-tissue damage, preservation of joint range of motion, and avoidance of metallic implants. In some patients, loss of correction can occur and a conventional proximal interphalangeal arthroplasty may be required.
Percutaneous techniques can not be performed without adequate instruments and experience. Our results are under investigation; however, these procedures offer an interesting alternative with many potential advantages.
- Austin DW, Leventen EO. A new osteotomy for Hallux valgus: a horizontally directed V displacement osteotomy of the metatarsal head for hallux valgus and primus varus. Clin Orthop Relat Res. 1981; 157:25-30.
- Hawkins FB, Mitchell CL, Hedrick DW. Correction of hallux valgus by metatarsal osteotomy. J Bone Joint Surg. 1945; 37:387-394.
- Homann G. Symptomatische oder physiologische behandlung des hallux valgus. Munch Med Wschr. 1921; 68:1042-1045.
- Reverdin J. De la dèviation en dehors du gros orteil (hallux valgus, vul, oignon, bunions, Ballen) et de son traitement chirurgical. Trans Int Med Congr. 1881; 2:408-412.
- Bösch P, Wanke S, Legenstein R. Hallux valgus correction by the method of Bösch: a new technique with a seven-to-ten-year follow-up. Foot Ankle Clin. 2000; 5:485-498.
- Magnan B, Bortolazzi R, Samaila E, et al. Percutaneous distal metatarsal osteotomy for correction of hallux valgus. Surgical technique. J Bone Joint Surg Am. 2006; 88 (Suppl 1 Pt 1):135-148.
- Magnan B, Pezzè L, Rossi N, et al. Percutaneous distal metatarsal osteotomy for correction of hallux valgus. J Bone Joint Surg Am. 2005; 87:1191-1199.
- Migues A, Slullitel G, Vescovo A, et al. Peripheral foot blockade versus popliteal fossa nerve block: a prospective randomized trial in 51 patients. J Foot Ankle Surg. 2005; 44:354-357.
Drs Migues, Campaner, Slullitel, Sotelano, Carrasco, and Solari are from the Institute of Orthopedics, Carlos E. Ottolenghi, Hospital Italiano de Buenos Aires, Argentina.
Correspondence should be addressed to: Gustavo Campaner, MD, Institute of Orthopedics, Carlos E. Ottolenghi, Hospital Italiano de Buenos Aires, Potosí 4215, Buenos Aires, C1199ACK, Argentina.