Surgical Strategies: Ludloff First Metatarsal Osteotomy

Transcription

1 FOOT &ANKLE INTERNATIONAL Copyright 2007 by the American Orthopaedic Foot & Ankle Society, Inc. DOI: /FAI Surgical Strategies: Ludloff First Metatarsal Osteotomy Su-Young Bae, M.D.; Lew C. Schon, M.D. Baltimore, MD BACKGROUND AND PROCEDURE Moderate to severe hallux valgus deformities associated with a wide first intermetatarsal angle require a first metatarsal osteotomy for adequate correction. A variety of procedures have been introduced such as the crescentic, chevron, scarf, closing or opening wedge osteotomies of the first metatarsal base, and the Ludloff and Mau procedures. 7,8,10,15,16,17,24,27 Recently the Ludloff osteotomy has risen in popularity as demonstrated in clinical and biomechanical publications. 1,2,3,5,6,11,13,22,26 The Ludloff first metatarsal osteotomy was described in 1918 by Ludloff. 14 Indications for the procedure were substantial metatarsus primus varus and hallux valgus deformities. As originally described, the Ludloff procedure was designed as a long oblique osteotomy from dorsal proximal to plantar distal that allowed realignment and shortening of the first metatarsal. A distinctive advantage of the geometry of the Ludloff osteotomy is that the relatively large proximal bone fragment allows secure fixation. Although Ludloff claimed excellent results, the original technique before the advent of rigid screw fixation had complications such as delayed union, nonunion, and malunion. MODIFICATIONS After the introduction of screw fixation in orthopaedics, Patton and Zelichowski 21 described the Ludloff osteotomy with two 2.0- or 2.7-mm cortical screws for fixation. These authors also used a shorter midshaft osteotomy. Their use of the larger proximal bone fragment for fixation highlighted an advantage of the geometry of the osteotomy and foreshadowed future creative fixation techniques. Corresponding Author: Lew C. Schon, M.D. Union Memorial Orthopaedics c/o Lyn Camire 3333 North Calvert Street #400 Baltimore, MD Lyn.Camire@Medstar.Net For information on prices and availability of reprints, call X226 Indications for the Patton and Zelichowski 21 modification of the Ludloff osteotomy are symptomatic hallux valgus with an intermetatarsal angle of more than 13 degrees or splayfoot or forefoot adductus with an intermetatarsal angle of more than 11 degrees and normal metatarsocuneiform joint inclination. In their method, the osteotomy, is through the mid-diaphysis beginning dorsally 1.5 cm distal to the metatarsocuneiform joint and progressing distally and plantarward to the junction of the diaphysis and metaphysis, exiting proximal to the MTP joint capsule (the sesamoid apparatus). A crucial step is movement of the distal fragment, which is rotated and translated laterally. They also mentioned lengthening of the first metatarsal bone to avoid metatarsalgia. A bone clamp was used to gain temporary fixation before screw fixation. Postoperatively, these authors recommended nonweightbearing in a below-knee cast for 6 weeks. Although results were encouraging with this modification, it was still difficult to obtain proper position of the metatarsal head, because manual skill was needed to perform simultaneous sliding and rotation and secure fixation, especially in osteoporotic bone with thin cortices in the diaphysis. Currently, the configuration of the modified Ludloff osteotomy, as popularized by Myerson, 18 is an oblique cut starting more proximally, 5 to 8 mm anterior to the metatarsocuneiform joint, and continuing toward the plantar-distal diaphysis with about 30 degrees of inclination (Figure 1). 18 This permits a broad area of bony contact involving some metaphyseal bone for better stability and healing and allows for a greater angular correction by being closer to the apex of the deformity. Initially, only the dorsal two thirds of the cut is done and a proximal screw is directed from dorsal to plantar. The osteotomy is then completed, and the distal fragment is rotated around the proximal screw. The second screw is placed about 1 cm distal to the first one to finalize fixation. It has consequently changed into a purely rotational osteotomy on the axis of the first screw and proximal metatarsal osteotomy. Other surgeons have varied this osteotomy in terms of screw size, from 2.0 to 3.5 mm, and in screw type, direction of the screw, and length of the osteotomy. 9,13 137

2 138 BAE AND SCHON Foot & Ankle International/Vol. 28, No. 1/January 2007 Fig. 1: Ludloff osteotomy. The cut angle is from dorsal proximal to plantar distal at a 30-degree inclination. Initially only the proximal three quarters of the osteotomy is completed. In 2003, Nyska et al. 20 modified the osteotomy angle by coronal tilting plantar-laterally by 10 degrees to avoid head elevation 4,19,20 (Figure 2). Recently, Schon et al. 25 modified this osteotomy by adding supplementary axial fixation with one or two Kirschner wires in addition to the standard one or two screws to prevent loss of reduction or dorsal malunion (Figures 3, C; 4, D; and 5, B and C). This modification was recommended for use in small or osteoporotic metatarsals. In a biomechanical study, Jung et al. 12 demonstrated that the two-wire and one-screw technique was not significantly weaker than the technique using two screws without wires. Current results, contrasted with the original Ludloff osteotomy, are very encouraging. 3,5,6,7,11 Modification of the proximal screw direction after an incomplete cut helps to prevent metatarsal shortening, which was one of the common complications of the original procedure. In 2004, Chiodo et al. 6 independently reviewed cases by Schon and Myerson. They reported excellent correction of the first intermetatarsal angle in moderate to severe hallux valgus with few complications at 3-year followup in a retrospective study of 70 feet. Preoperatively, the mean hallux valgus and first intermetatarsal angles were 31 degrees and 16 degrees and were corrected postoperatively to a mean of 11 degrees and 7 degrees, respectively. In the sagittal plane, the first metatarsal was plantarflexed by an average of 1 mm. The first metatarsal was shortened by an average of 2.3 mm (range, 0 to 8 mm). No patients reported pain under the second metatarsal head after surgery. The mean AOFAS metatarsophalangeal-interphalangeal score improved from 54 (range 29 to 69) to 91 (range 62 to 100) points, and 69 patients (98%) were satisfied with the results of surgery. More recently, Hofstaetter et al. 11 reported favorable results in their 3-year follow up retrospective study of 70 feet in 67 patients. The average AOFAS score improved significantly from 55.2 ± 15.2 points to 86.6 ± 15.2 points at follow up. The average hallux valgus angle (HVA) improved from 37 ± 8 degrees to 12 ± 11 degrees, the intermetatarsal angle (IMA) improved from 18 ± 2 degrees to 8 ± 4 degrees, the sesamoid position improved significantly, and all osteotomies healed at 37 ± 6 months followup. A comparison of the mechanical strength of proximal metatarsal osteotomies found no significant difference between the strength to resist dorsiflexion bending load of proximal crescentic and proximal chevron osteotomies but noted that the Ludloff value was significantly stronger than the crescentic and chevron osteotomies and similar to the scarf osteotomy. 26 In this study, the average strengths were Mau, 530 kpa; biplanar, 508 kpa; scarf, 428 kpa; Ludloff, 372 kpa; and crescentic, 199 kpa. The strength of the Ludloff osteotomy was lower than that of the Mau osteotomy because the Ludloff osteotomy is unstable with regard to ground reaction, but it can be reinforced by additional axial Kirschner wires(figure3,c;4,d;5,bandc). 12,25 CURRENT INDICATIONS The current indications for the Ludloff osteotomy are hallux valgus deformities with an HVA of more than 35 degrees, an IMA of more than 12 degrees, a sesamoid position of grade 2 or 3, no or mild arthritis at the metatarsocuneiform (MTC) joint, no radiographic instability of the MTC, no or mild arthritis of the MTP joint and a distal metatarsal articular angle (DMMA) of less than 10 degrees (Figure 4, A through D). Since the osteotomy achieves the correction by rotation, a DMAA over 10 degrees may be vulnerable to arthritis by making a congruent joint incongruent. Contraindications are active infection, an insensate foot, a noncompliant patient, severe arthritis of the MTC joint or the MTP joint, instability of MTC joint, and a DMAA of more than 10 degrees unless performed with an additional distal metatarsal osteotomy. Osteoporosis is a relative contraindication unless supplementary fixation is used. OPERATIVE TECHNIQUE Fig. 2: The saw blade should be angled 10 degrees toward the fifth metatarsal to avoid head elevation. The procedure is performed through separate dorsal and medial incisions.

3 Foot & Ankle International/Vol. 28, No. 1/January 2007 LUDLOFF FIRST MT OSTEOTOMY 139 (A) (B) (C) Fig. 3: Dorsal view of the procedure (A). The first screw is placed 12 to 14 mm distal to the osteotomy before rotation (B). After rotation on the axis of the first screw, the medial prominence of proximal bone shelf should be removed (C). Fixation can be performed by two screws, one screw with two supplementary Kirschner wires, or two screws with one or two supplementary Kirschner wires. (Reprinted with permission from Schon, LC; Dom, KJ; Jung HG. Clinical Tip: Stabilization of the proximal Ludloff osteotomy. Foot Ankle Int. 26: , 2005.) The dorsal incision is made first and is aligned over the first webspace. Through this incision the transverse metatarsal ligament and adductor hallucis tendon are released. The lateral capsule is perforated or stretched to allow the hallux to move into a mild varus position (10 to 15 degrees with minimal manual resistance). The medial aspect of the first metatarsal and MTP joint are exposed through a separate 8-cm medial longitudinal incision extending from the MTC joint to the base of the proximal phalanx. Through a medial longitudinal capsulotomy, the medial eminence is freed from capsular attachments. A minimal resection of the medial eminence is done beginning 2 to 3 mm medial to the sagittal sulcus. An oblique osteotomy is next made with the saw beginning 2 mm distal to the MTC joint and extending from dorsal proximal to plantar distal. 6,23 The distal extent of the osteotomy is proximal to the MTP capsule and sesamoid apparatus. The line should be marked before the osteotomy cut is done. The plane of the osteotomy is oriented at an angle approximately 30 degrees from the long axis of the first metatarsal (Figure 1). Thus, it exits the plantar distal metatarsal approximately 1 cm proximal to the sesamoids. The surgeon should raise

4 140 BAE AND SCHON Foot & Ankle International/Vol. 28, No. 1/January 2007 (A) (B) (C) (D) Fig. 4: Preoperative weightbearing photograph (A) and anteroposterior radiograph (B) of a patient with severe hallux valgus with wide intermetatarsal angle. Postoperative photograph (C) and radiograph (D) shows the correction of the IMA. Two Kirschner wires were added for reinforcement of screw fixation. the saw blade handle 10 degrees from the horizontal plane aimed at the fifth metatarsal (Figure 2). This orientation of the plane of the osteotomy will prevent dorsal elevation of the distal fragment. Initially, only the proximal three-quarters of the osteotomy is completed, leaving intact the most distal aspect (Figure 1). The incomplete osteotomy is fixed with a cannulated lag screw (3.0, 3.5 or 4.0 mm) placed perpendicular to the plane of the cut approximately 12 to 14 mm distal to the proximal aspect of the osteotomy (Figure 3, A). Placing a scalpel blade into the plane of the osteotomy will assist the surgeon in achieving perpendicular placement of the screw (Figure 6). If the screw is off the plane, the

5 Foot & Ankle International/Vol. 28, No. 1/January 2007 LUDLOFF FIRST MT OSTEOTOMY 141 (A) (B) (C) Fig. 5: Typically two cortical screws are used for fixation (A). Instead of the distal screw, two K-wires can be used for osteoporotic bone (B). Sometimes the addition of one or two K-wires to the two cortical screws is helpful for stable fixation (C). rotation around the screw will be similarly off plane and will lead to poor fixation or facture of the osteotomy. The screw is then backed out just enough to allow rotation of the osteotomy. The osteotomy is then completed, and the distal fragment is rotated about the axis of the screw until the intermetatarsal angle is corrected (Figure 3B). Overcorrection is possible, and the IMA should not be reduced to less than 3 to 5 degrees. Gentle traction on a towel clamp placed on the plantar proximal shelf and translational pressure on the distal Fig. 7: The distal fragment is rotated and held with a pointed reduction clamp (two black arrows). Gentle traction on the plantar proximal shelf with a towel clamp (open arrow) and translational pressure on the metatarsal head with a finger (open triangle) help maintain proper position. Fig. 6: Plane of the Ludloff osteotomy and the direction of the first screw. The first screw is directed perpendicular to the plane of the osteotomy (scalpel blade). metatarsal with a finger will help hold the reduction (Figure 7). The osteotomy is then held with a bone reduction tenaculum to achieve compression. Once the desired correction has been obtained, the initial screw is tightened. Fluoroscopy will aid in confirmation of position and fixation.

6 142 BAE AND SCHON Foot & Ankle International/Vol. 28, No. 1/January 2007 Fig. 8: If there is space for a third screw, a fully threaded 2.5mm cortical screw can be added. A second, more distal screw is then inserted perpendicularly across the osteotomy. Often it is not possible to place this second screw exactly perpendicular to the plane of the cut. In these cases, a fully-threaded 2.5-mm cortical screw can be inserted from plantar to dorsal (Figure 3, C) The screw is bicortical and is inserted while the bone tenaculum holds the osteotomy firmly compressed to prevent gapping or shifting. If the screw is placed in a nonperpendicular fashion in a lag mode, the osteotomy tends to shift with progressive tightening of the screw and the correction will be diminished. When dealing with osteoporotic bone, two inch Kirschner wires can be inserted instead of the second screw or one or two inch Kirschner wires can be added after the second screw fixation (Figure 3, C; 4, D; and 5). The wires are placed from the proximal medial aspect of the osteotomy into the metatarsal head or shaft distally. The wires are adjusted for proper length by fluoroscopy. Once the length is determined, the wires are backed out 1 cm, cut, bent, and pushed into final position against the bone. If there is space, a third fully threaded 2.5 mm cortical screw can be added to the construct (Figure 8). The prominent bone shelf is then resected with a saw (Figure 9, A and B), with care not to compromise the screw fixation when removing this shelf of bone. The capsulorrhaphy includes resecting a triangular section of the plantar capsule 3 mm proximal to the base of the proximal phalanx (Figure 10 A and B). The base of the triangle (approximately 1 cm) is dorsal, and the apex is at the medial sesamoid. Care is taken not to injure the plantar medial hallucal nerve. The capsule is closed with 2-0 vicryl suture on a GU needle (3/4 short radius tapered needle) shortening the plantar limb of the capsule and repositioning the sesamoids. The plantar and dorsal capsule is then closed. Postoperative Care Patients are allowed to bear weight as tolerated on their heel and lateral forefoot in an open, hard-soled surgical shoe with crutches for balance. This is followed by gradual (A) (B) Fig. 9: A, Plantar bone shelf makes a prominence after rotation. B, This shelf is shaved down with a sagittal saw to avoid soft tissue irritation. In this case, we used two K-wires instead of a distal screw.

7 Foot & Ankle International/Vol. 28, No. 1/January 2007 LUDLOFF FIRST MT OSTEOTOMY 143 (A) (B) (C) (D) Fig. 10: Redundant capsule (A and B) is resected as a dorsal based triangular shape (C). Proximal and distal capsular margins are closed with 2-0 vicryl suture (D). resumption of full weightbearing on the flat foot as tolerated, typically starting at 6 weeks. Typically, by 12 weeks there is full weightbearing on the first metatarsal. Dressing changes are demonstrated to the patient using a 2-inch elastic wrap at 10 to 14 days. The hallux is held in a neutral position (straight relative to the metatarsal), and the midfoot is wrapped in comfortable compression. The wrap is discontinued after 6 weeks if position is acceptable and there is no swelling. A toe spacer is used for 12 weeks. The postoperative shoe is discontinued at 8 to 14 weeks with evidence of bone healing radiographically and if the swelling and pain are controlled. SUMMARY The Ludloff osteotomy is an effective osteotomy for moderate to severe hallux valgus deformities. The current modifications provide for good angular correction and mechanical stability. Two advantages of the broad area of bony contact are predictable healing and the possibility for supplementation of fixation with additional screws or wires. Although the osteotomy is more difficult to perform than a distal osteotomy, it is a similar technical challenge to the other proximal osteotomies. Surgical steps that are outlined should improve the results. In particular, it is important 1) to make the long oblique osteotomy beginning as proximal as possible, 2) not to complete the osteotomy before the first screw placement, 3) to compress the osteotomy site after rotation with a bone reduction tenaculum while inserting the second screw or K-wires, and 4) to carefully remove the shelf of protruding bone without compromising the fixation. With this surgery we find that patients are 75% clinically healed by 3 months and 90% healed by 6 months, although radiographic healing occurs between 10 and 14 weeks. Results and complications are similar to other proximal osteotomies, but shortening and dorsiflexion malunion are uncommon. As with all surgeries, familiarity with the various elements of the procedure will facilitate correction and improve patient satisfaction. REFERENCES 1. Acevedo, JI: Fixation of metatarsal osteotomies in the treatment of hallux valgus. Foot Ankle Clin. 5(3): , Acevedo, JI; Sammarco, VJ; Boucher, HR; et al.: Mechanical comparison of cyclic loading in five different first metatarsal shaft osteotomies. Foot Ankle Int. 23: , Basile A; Battaglia A; Campi A: Retrospective analysis of the Ludloff osteotomy for correction of severe hallux valgus deformity. Foot Ankle Surg. 7:1 8, Beischer AD; Ammon P; Corniou A; Myerson M: Three-dimensional computer analysis of the modified Ludloff osteotomy. Foot Ankle Int. 26: , Chao W; Mizel MS: Specialty update: What s new in foot and ankle surgery. J. Bone Joint Surg. 88-A: , Chiodo, CP; Schon, LC; Myerson MS: Clinical Results with the Ludloff osteotomy for correction of adult hallux valgus. Foot Ankle Int. 25 : , Cisar, J; Holz, U; Jenninger W, Uhlig, C: Ludloff s osteotomy in hallux valgus. Aktuelle Traumatol. 13: , 1983.

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