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Modified Scarf Osteotomy with Medial Capsular Interposition in Great Toe and Metatarsal Shortening Offset Osteotomy in Lesser Toes for Rheumatoid Deformity

Hirao, Makoto, MD, PhD1; Ebina, Kosuke, MD, PhD1; Tsuboi, Hideki, MD, PhD2; Nampei, Akihide, MD, PhD3; Tsuji, Shigeyoshi, MD, PhD4; Noguchi, Takaaki, MD, PhD4; Owaki, Hajime, MD, PhD5; Yoshikawa, Hideki, MD, PhD1; Hashimoto, Jun, MD, PhD4

JBJS Essential Surgical Techniques: December 26, 2018 - Volume 8 - Issue 4 - p e27
doi: 10.2106/JBJS.ST.18.00004
Subspecialty Procedures
Disclosures

Background: Arthrodesis of the first metatarsophalangeal (MTP) joint has been recommended for severe hallux valgus deformity in patients with rheumatoid arthritis. We developed an alternative procedure that preserves motion of the first MTP joint while restoring alignment and balance to the forefoot. This procedure was shown to be effective in a series of 60 patients with a 3-year follow-up.

Description: We perform a modified Scarf osteotomy, with the longitudinal first metatarsal cut parallel to the sole of the foot and with shortening of the metatarsal to realign the first ray. This is combined with an interpositional capsular arthroplasty of the first MTP joint and shortening offset osteotomies of the lesser metatarsals.

Alternatives: Alternatives include arthrodesis of the first MTP joint combined with resection arthroplasty of the lesser MTP joints, or of all 5 MTP joints, or perhaps interpositional (total) joint arthroplasty for severe rheumatoid forefoot deformity/destruction.

Rationale: The purpose of the modified Scarf osteotomy is preservation of motion of the first MTP joint and protection against destruction of the rheumatoid joint. The metatarsal shortening offset osteotomy provides rigid stabilization at the site of osteotomy after dynamic correction to make the transverse arch.

1Department of Orthopaedics, Osaka University Graduate School of Medicine, Suita, Japan

2Department of Orthopaedics, Osaka Rosai Hospital, Sakai, Japan

3Nampei Orthopaedics and Rheumatology Clinic, Katsuragi, Japan

4Department of Orthopaedics/Rheumatology, National Hospital Organization, Osaka Minami Medical Center, Kawachinagano, Japan

5Department of Orthopaedics, Japan Community Health Care Organization (JCHO), Osaka Hospital, Osaka, Japan

E-mail address for M. Hirao: makohira777@gmail.com

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Introductory Statement

Modified Scarf osteotomy combined with metatarsal shortening offset osteotomy of the lesser toes provides stable forefoot realignment with preservation of the motion of the first metatarsophalangeal (MTP) joint.

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Indications & Contraindications

Indications

  • Symptomatic rheumatoid arthritis and deformity of the forefoot, specifically the first ray.

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Contraindications

  • Problems (e.g., pes planus, hallux flexus, and inversion deformity) that require creation of a medial arch structure, for which plantar flexion osteotomy of the first metatarsal bone is preferable.
  • Pencil deformity of the metatarsal head of the lesser toes due to progression of rheumatoid disease.

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Step-by-Step Description of Procedure

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Step 1: Preoperative Planning

On a standing anteroposterior radiograph, plan the resection of the first metatarsal as the amount equal to the overlap of the first metatarsal and the base of the proximal phalanx, and plan to resect enough length of the lesser metatarsals to allow reduction of the MTP joints while keeping these metatarsals longer than the first.

  • Use a preoperative standing anteroposterior foot radiograph to plan the osteotomies.
  • Define the amount of resection of the first metatarsal as being equal to the amount of overlap of the first metatarsal and the base of the proximal phalanx (designated by double-headed arrow 1 in Fig. 1) as seen on a standing anteroposterior radiograph. Avoid leaving the first metatarsal longer than the second.
  • Plan to resect enough length of the lesser metatarsals to allow reduction of the MTP joints while keeping these metatarsals longer than the first (the dotted line in Fig. 1 indicates the new position of the shortened first metatarsal). The actual length of the shortening osteotomy of the metatarsals in the lesser toes is 3 mm less than the preoperatively measured length. (The offset correction site is fixed [hooked] into 3-mm-deep grooves of the cortical bone). For example, if 10 mm of shortening is measured preoperatively, the actual length of the shortening osteotomy will be 7 mm.

Fig. 1

Fig. 1

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Step 2: Operating Room Setup (Fig. 2)

With the patient supine, and a fluoroscope in place to later check alignment and correction, ensure that full knee joint flexion is possible so that the foot can be placed parallel to the operating table.

  • The operation is performed under tourniquet control with the patient in the supine position.
  • Fluoroscopy is set up, as it will be used to check alignment after the osteotomy and correction.
  • Drape the whole lower limb on the affected side.
  • Ensure that full knee joint flexion is possible so that the foot can be placed parallel to the operating table.

Fig. 2

Fig. 2

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Step 3: Incisions (Fig. 3)

Make the incisions.

  • Make a 2-cm longitudinal dorsal incision between the first and second metatarsal heads.
  • Make a 7-cm longitudinal incision medially from the midportion of the first proximal phalanx to the base of the first metatarsal, parallel to both.
  • Confirm the position of the first tarsometatarsal (TMT) joint (arrow in Fig. 3-B).
  • Make 3 to 4-cm longitudinal dorsal incisions between the second and third and the fourth and fifth metatarsal heads.
  • If there is a claw toe deformity, add a 1.5-cm longitudinal skin incision on the proximal interphalangeal (PIP) joint.

Fig. 3

Fig. 3

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Step 4: Approach

Approach the lesser toes through the lateral 2 dorsal toe incisions and the great toe through the dorsal first web space incision.

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Lesser Toes (Fig. 4-A)

  • Through the lateral 2 dorsal incisions, expose the neck of each of the 4 lesser metatarsals in preparation for osteotomy.
  • Identify the extensor digitorum longus (EDL) tendon and extensor digitorum brevis (EDB) tendon.
  • Retract the EDL medially and the EDB laterally.
  • Incise the periosteum longitudinally (arrow in Fig. 4-A-2) and retract it to expose the metatarsal neck.

Figs. 4-A, 4-B, and 4-C Approaches.

Fig. 4-A

Fig. 4-A

Fig. 4-B

Fig. 4-B

Fig. 4-C

Fig. 4-C

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Great Toe (Fig. 4-B)

  • Through the dorsal first web space, dissect the adductor hallucis tendon from the base of the proximal phalanx and secure its stump with a heavy suture (triple mattress).
  • Release the transverse metatarsal ligament and incise the lateral capsule between the first metatarsal head and the lateral sesamoid longitudinally from the proximal phalanx to the midpart of the first metatarsal shaft to facilitate reduction of the sesamoids later.
  • Through the medial incision, after retracting and protecting the medial dorsal hallucal nerve, use the medial capsule of the first MTP joint to create a 10-mm-wide proximally based flap (Fig. 4-C).
  • Keep the flap moist with a saline solution-soaked sponge.

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Step 5: Osteotomy and Reduction

Resect a sufficient amount of each lesser metatarsal neck to allow reduction of the respective MTP joint (Fig. 5-A); to correct the hallux valgus deformity, perform sufficient shortening and translation of the first metatarsal shaft through a horizontal longitudinal osteotomy (Fig. 5-B).

Figs. 5-A and 5-B Osteotomy and reduction.

Fig. 5-A

Fig. 5-A

Fig. 5-B

Fig. 5-B

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Lesser Toes

  • Retract the soft tissue, including the periosteum, medially and laterally from the metatarsal neck.
  • Make a first saw cut perpendicular to the neck and 1.5 cm proximal to the metatarsal head.
  • Note the length of the neck to be resected as measured on the preoperative radiographs.
  • Make a second cut at the measured length proximal to the first cut.
  • After resecting the free bone segment, pull the distal metatarsal head fragment proximally and open the MTP joint capsule using a scalpel.
  • Debride inflamed synovial tissue and release any soft-tissue adhesions within the MTP joint.
  • Partially release the insertions of the medial and lateral collateral ligaments sharply as necessary to achieve an adequate reduction of each MTP joint.

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Great Toe

  • Through the medial incision, incise and elevate the periosteum and soft tissue from around the dorsal, plantar, and medial aspects of the first metatarsal.
  • Remove the medial metatarsal head osteophyte (bunion).
  • Draw the preplanned osteotomy cuts on the bone.
  • Using an oscillating saw, make the first cut 10 mm proximal to the metatarsal head and perpendicular to the longitudinal axis of the first metatarsal.
  • Make the second longitudinal cut parallel to the sole of the foot1. To avoid pronation of the first metatarsal head and loss of the longitudinal arch of the foot, the direction of the bone saw during the osteotomy should not be parallel to the transverse axis of the first metatarsal. Rather, an oblique direction (from medial-dorsal to lateral-plantar) is recommended.
  • Make the third cut on the plantar cortex and 10 mm distal to the TMT joint.
  • Make the fourth cut parallel to the first cut and at the premeasured distance (Step 1) proximal to the first cut.
  • Make the fifth cut parallel to the third cut and at the premeasured distance (Step 1) distal to the first cut.
  • Partially resect the lateral end of the dorsal (proximal) bone fragment to make reduction easier.
  • Confirm release of the insertion of the lateral collateral ligament from the medial approach and remove any proliferated synovial tissue.
  • Translate the distal bone fragment laterally, and confirm that the metatarsal head is aligned with the sesamoid bones.

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Step 6: Fixation

Lock the distal fragment (metatarsal head) of the lesser metatarsals into 3-mm-deep grooves in the cortical bone of the proximal fragment and then secure it to the proximal fragment with a 1.2-mm Kirschner wire (Fig. 6-A); shift the distal bone fragment of the first metatarsal laterally and securely fix it with screws (Fig. 6-B).

Figs. 6-A and 6-B Fixation.

Fig. 6-A

Fig. 6-A

Fig. 6-B

Fig. 6-B

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Lesser Metatarsals

  • Fashion the cortex of the distal end of the proximal stump into a narrow spike with 2 grooves dorsally using a power burr.
  • Ream the medullary canal of the metatarsal head fragment using the burr to create a mortise to receive the proximal fragment spike.
  • Insert the spike of the proximal fragment into the medullary canal mortise of the distal fragment.
  • First insert a 1.0 or 1.2-mm Kirschner wire antegrade from the proximal end of the distal fragment, through the MTP, PIP, and distal interphalangeal (DIP) joints to exit at the toe apex.
  • Then reduce the metatarsal neck osteotomy and drive the Kirschner wire in a retrograde fashion into the medullary canal and across the TMT joint. The dorsal spike of the proximal fragment should sit securely in the medullary canal mortise of the distal fragment, stabilized by the Kirschner wire.
  • Place bone chips from the resection around the osteotomy sites to fill any defects.

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First Metatarsal

  • Use 3 AcuTwist screws (Acumed) for the fixation.
  • Before fixation, place chips from the resected bone into the medullary canal of both fragments to act as bone graft.
  • After manually aligning the osteotomy, insert 3 1.1-mm guidewires for 2 screws to stabilize the metatarsal head and neck and 1 screw to secure the proximal aspect of the osteotomy.
  • Confirm proper placement of the guidewires with fluoroscopy.
  • Complete the fixation as the fragments are held securely with Kocher forceps.
  • After fixation, resect any medially overhanging bone from the proximal fragment with a power saw.
  • Use fluoroscopy to confirm that any overhanging bone has been removed.

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Step 7: Medial Capsular Interposition and Closure

After correction of the hallux valgus deformity using the modified Scarf osteotomy, interpose the 10-mm-wide capsular flap into the first MTP joint (Fig. 7).

  • Grasp the 10-mm-wide capsular flap with Kocher forceps that have been passed from the lateral side through the first MTP joint, and pull it laterally so that it is interposed between the base of the proximal phalanx and the metatarsal head.
  • Apply tension to the flap so that the toe assumes a slightly varus position.
  • Suture the proximal end of the flap to the stump of the dissected adductor hallucis tendon and the soft tissue surrounding the metatarsal head (Videos 1 and 2).
  • Close the skin over drains for all wounds (Fig. 8).
Fig. 7

Fig. 7

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Fig. 8

Fig. 8

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Results

In our series of 76 cases in 60 patients, sufficient reduction of the hallux valgus deformity was achieved consistently even in cases with severe destruction (Larsen grade 4 or 5) of the first MTP joint due to rheumatoid arthritis2. Painful callosities plantar to the lesser-toe metatarsal heads routinely disappeared following the metatarsal shortening offset osteotomies3. This combined joint-preserving surgery for the great and lesser toes resulted in greater plantar pressure distribution under the first MTP joint and lower plantar pressure distribution under the second and third MTP joints with weight-bearing4.

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Pitfalls & Challenges

  • To avoid the “troughing” phenomenon, and to obtain stable fixation, abundant bone-chip transplantation into the metatarsal canal after the Scarf osteotomy is required.
  • To avoid pronation of the first metatarsal head and loss of the longitudinal arch of the foot, the direction of the bone saw during osteotomy should not be parallel to the transverse axis of the first metatarsal. Rather, an oblique direction (from medial-dorsal to lateral-plantar) is recommended.
  • Any residual pronation deformity of the great toe should be corrected at the time of surgery using an Akin osteotomy of the proximal phalanx.
  • Persistent valgus hindfoot deformity carries some risk for recurrence of the hallux valgus deformity and often can be managed with shoe inserts.
  • Conversely, persistent varus hindfoot deformity poses some risk for the recurrence of subluxation/dislocation of the lesser-toe MTP joints.

Note: The authors thank Tsukasa Kumai (Faculty of Sport Science, Waseda University/Department of Orthopaedics, Nara Medical University) and Shuji Horibe (Faculty of Comprehensive Rehabilitation, Osaka Prefecture University) for their valuable instructions for this study.

Published outcomes of this procedure can be found at: J Bone Joint Surg Am. 2018 May 2;100(9):765-76 and Mod Rheumatol. 2017 Nov;27(6):981-9.

Disclosure: The authors indicated that no external funding was received for any aspect of this work. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSEST/A226).

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References

1. Tanaka Y. [Horizontal first metatarsal osteotomy]. Kansetsugeka. 2004;23:731-6. Japanese.
2. Kushioka J, Hirao M, Tsuboi H, Ebina K, Noguchi T, Nampei A, Tsuji S, Akita S, Hashimoto J, Yoshikawa H. Modified scarf osteotomy with medial capsule interposition for hallux valgus in rheumatoid arthritis: a study of cases including severe first metatarsophalangeal joint destruction. J Bone Joint Surg Am. 2018 May 2;100(9):765-76.
3. Hirao M, Ebina K, Tsuboi H, Nampei A, Kushioka J, Noguchi T, Tsuji S, Owaki H, Hashimoto J, Yoshikawa H. Outcomes of modified metatarsal shortening offset osteotomy for forefoot deformity in patients with rheumatoid arthritis: short to mid-term follow-up. Mod Rheumatol. 2017 Nov;27(6):981-9. Epub 2017 Feb 1.
4. Ebina K, Hirao M, Takagi K, Ueno S, Morimoto T, Matsuoka H, Kitaguchi K, Iwahashi T, Hashimoto J, Yoshikawa H. Comparison of the effects of forefoot joint-preserving arthroplasty and resection-replacement arthroplasty on walking plantar pressure distribution and patient-based outcomes in patients with rheumatoid arthritis. PLoS One. 2017 Aug 29;12(8):e0183805.

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