Scarf Osteotomy of the First Metatarsal

Definition

Scarf is a carpentry term, meaning "a joint made by bevelling two beams to correspond". The aim is to set the two beams end-to-end in order to make a longer beam, providing a longer bearing surface. The join - or the cut - is similar to a flash of lightning, on a thunder sky. This is why it is called in France: "trait de Jupiter" (in Spain "rayo de Jupiter"); in France Jupiter is Zeus.

The name "scarf" was given in 1984 by Lowell Scott Weil to this first metatarsal osteotomy in regard to its cuts. However, in this osteotomy, instead of end-to-end lengthening, the plantar beam which includes the first meta-tarsal head, shifts laterally to the dorsal beam that is stable throughout its length. This displacement can be not only lateral, but also in several directions, resulting in a great versatility, to adapt to the different hallux valgus deformities. Furthermore, the stability is notable, resulting from a large fragment area contact and from the double chevron shaped cut - proximal and distal - (Fig. 03a).

Distal Chevron Procedure Hallux Valgus

Fig 03a1. The scarf term.

The scarf term comes from the French term "trait de Jupiter" (Jupiter is the Roman name of the Greek god: Zeus); it certainly comes from lightening observed in a thunder sky. In Spanish it is called "Rayo de Jupiter". English people talk about "Jupiter cut" or "scarf'. It was first applied to the carpentry (to lengthen a beam) then to the forefoot surgery, particularly to the first metatarsal. L. S. Weil gave the name scarf to this osteotomy.

Fig 03a1. The scarf term.

The scarf term comes from the French term "trait de Jupiter" (Jupiter is the Roman name of the Greek god: Zeus); it certainly comes from lightening observed in a thunder sky. In Spanish it is called "Rayo de Jupiter". English people talk about "Jupiter cut" or "scarf'. It was first applied to the carpentry (to lengthen a beam) then to the forefoot surgery, particularly to the first metatarsal. L. S. Weil gave the name scarf to this osteotomy.

Scarf Carpentry

Fig. 03a2. Scarf, a carpentry term.

Scarf, or "trait de Jupiter", in an old market - picture communicated by B. Baudet (Toulouse, France). The two beams are joined by a "trait de Jupiter" cut.

Fig. 03a2. Scarf, a carpentry term.

Scarf, or "trait de Jupiter", in an old market - picture communicated by B. Baudet (Toulouse, France). The two beams are joined by a "trait de Jupiter" cut.

Trait Jupiter Scarf

Fig. 03a3. Ship's carpentry.

1. Scarf cuts, with and without lock piece (picture provided by E. Maceira, Madrid).

2. Scarf in a ship's sheathing.

3. Scarf in a ship's keel is necessary to have both a sufficient length and to follow the changing keel direction.

Fig. 03a3. Ship's carpentry.

1. Scarf cuts, with and without lock piece (picture provided by E. Maceira, Madrid).

2. Scarf in a ship's sheathing.

3. Scarf in a ship's keel is necessary to have both a sufficient length and to follow the changing keel direction.

Roman Keel Scarf

Fig. 03a4. Scarf cut in carpentry and in forefoot surgery.

In the 1st metatarsal, the scarf cut is the same as in carpentry, but its aim is not end-to-end lengthening of the two fragments, but rather to displace only the plantar one, primarily in lateral shifting - but also in several directions, resulting in great versatility. The large fragment area is an important factor of stability of this osteotomy.

Fig. 03a4. Scarf cut in carpentry and in forefoot surgery.

In the 1st metatarsal, the scarf cut is the same as in carpentry, but its aim is not end-to-end lengthening of the two fragments, but rather to displace only the plantar one, primarily in lateral shifting - but also in several directions, resulting in great versatility. The large fragment area is an important factor of stability of this osteotomy.

History

1973 J. M. Burutaran [29] described a cut almost similar to the scarf cut, though not chevron-ended, and which was used to lengthen the first metatarsal.

1983 Charles Gudas and K. H. Z. Zygmunt [102] began to perform "z bunionectomies" with lateral shift of the plantar / distal fragment, including the metatarsal head.

1984 L. S. Weil [8, 26, 128, 129] gave the name "scarf" to this osteotomy (see above definition). With A. H. Borrelli, they studied the blood supply regarding this osteotomy, modified the scarf cuts, increased the length of the osteotomy, and made the first important clinical study, particularly with a long follow-up.

I met L. S. Weil in Chicago eleven years ago (February 1991) and since this moment I have begun to perform the scarf osteotomy. During these years I have performed more than

3,000 scarf osteotomies of the first metatarsal for hallux valgus. My personal contribution to the procedure has been: study of the first metatarsal anatomy [3], describing and emphasizing the displacements of the osteotomy, in particular the lowering of the first metatarsal head (in collaboration with B. Valtin*); the shortening of the first metatarsal (in collaboration with M. Maestro**); the use of a specially designed bone clamp, the internal fixation using a threaded head screw, placing the distal screw into the head to offer additional support to the osteotomy, and placing of scarf osteotomy in the global surgical management of static forefoot disorders [4-8, 15]. Many authors have already written about the scarf procedure [23, 24, 26, 29, 30, 31, 33, 34, 35, 38, 40, 41, 45-48, 53-57, 61, 62, 63, 64, 66, 70, 77-79, 82, 85, 87, 90, 91-96, 100-

* Bernard Valtin, Paris - France.

Fig. 03b. Surgical scarf story.

1. 1973 J. M. Burutaran (San Sebastian, Spain).

Fig. 03b. Surgical scarf story.

1. 1973 J. M. Burutaran (San Sebastian, Spain).

102, 104, 109, 110-112, 122, 124, 127-129, 131] (Fig. 03b).

Local Anatomy as Applied to the Scarf Osteotomy

- The first metatarsal bone is described in Fig. 04a; it shows that M1 is closely adapted to the scarf osteotomy; the cuts are extended from the distal to the proximal cancellous bone; the obliquity of the medial plantar surface is also adapted to the scarf osteotomy, as described further.

- The blood supply of the 1st metatarsal head (Fig. 04b). This study results from cadaver findings (5 feet with injection of the vessels) made in collaboration with Pr. Dominique Ligoro (CHU Bordeaux) [3], from the literature [58, 73, 107], but mainly from my operative and postoperative findings. We observed that the blood supply of the 1st metatarsal head can be entirely preserved; firstly, by the approach, lateral when performing the lateral release, medial when performing the medial approach, secondly by the cuts and the displacements of the scarf osteotomy.

- The Proximal Plantar Exposure (Fig. 05b) is performed proximal to the plantar neck vascular bundle; it is a "no man's land" allowing the osteotomy, the displacement and the fixation to be performed accurately and harmlessly.

- The local anatomy is more detailed in the enclosed CD-ROM.

Hallux Valgus

Fig. 04a. First metatarsal anatomy and scarf cuts.

The first metatarsal anatomy is closely adapted to the scarf osteotomy (specimen bones and CT scan). Lateral view 2. The longitudinal cut reaches the lateral surface (ls) in its plantar part, thus preserving almost the entire lateral surface which works as a strong beam. 3, 4. Proximal and distal transverse cuts.

Medial dorsal view. The medial border (mb) is an important landmark to perform the longitudinal cut (1) on the medial dorsal face. The distal transverse cut (4) is directed backwards, making a chevron with the longitudinal cut. Medial plantar view. This view reveals that the medial plantar surface (mps) is about 40° inclined from the horizontal plane. The scarf proximal transverse cut (3) is located on this face and is directed backwards.

3 mps

Fig. 04a. First metatarsal anatomy and scarf cuts.

The first metatarsal anatomy is closely adapted to the scarf osteotomy (specimen bones and CT scan). Lateral view 2. The longitudinal cut reaches the lateral surface (ls) in its plantar part, thus preserving almost the entire lateral surface which works as a strong beam. 3, 4. Proximal and distal transverse cuts.

Medial dorsal view. The medial border (mb) is an important landmark to perform the longitudinal cut (1) on the medial dorsal face. The distal transverse cut (4) is directed backwards, making a chevron with the longitudinal cut. Medial plantar view. This view reveals that the medial plantar surface (mps) is about 40° inclined from the horizontal plane. The scarf proximal transverse cut (3) is located on this face and is directed backwards.

Corectio Pedis

Fig. 04b1. First metatarsal distal blood supply. 1. Dorsal

The dorsalis pedis artery (1) is in fact dorsal-lateral, and it branches off to a nutrient artery (2) which is not constant. Then it supplies a fine branch, the metaphyseal capital dorsal branch (3) which penetrates the head through the dorsal capsule. Both the scarf approach and distal cut can respect this blood supply which nevertheless cannot alone adequately supply the metatarsal head: The main head blood supply is plantar.

Fig. 04b1. First metatarsal distal blood supply. 1. Dorsal

The dorsalis pedis artery (1) is in fact dorsal-lateral, and it branches off to a nutrient artery (2) which is not constant. Then it supplies a fine branch, the metaphyseal capital dorsal branch (3) which penetrates the head through the dorsal capsule. Both the scarf approach and distal cut can respect this blood supply which nevertheless cannot alone adequately supply the metatarsal head: The main head blood supply is plantar.

Cadaver Specimen Plantar

Fig. 04b2. First metatarsal distal blood supply. 2. Plantar

The medial plantar artery (4) runs on the dorsal aspect of the abductor muscle. It anastomoses with the first intermetatarsal plantar artery. The first intermetatarsal artery (6) is the main artery regarding the first metatarsal head, blood supply. It is created by the union of the deep plantar arch and the first perforating artery. It runs on the dorsal aspect of the lateral head of the flexor hallucis brevis muscle. In the scarf osteotomy, both of these arteries are preserved as a result of the Proximal Plantar Exposure (ppe). These arteries create an arch and join themselves under the metatarsal neck; this junction provides two metaphyseal capital branches: medial (5) and lateral (7) and similarly a branch to the medial and lateral sesamoids. The junction under the arch and the metaphyseal capital arteries are included in the plantar vascular bundle (8) which is also preserved both by the approach and the cuts of the scarf osteotomy. The plantar blood supply is the primary one of the 1st metatarsal head.

Blood Supply 1st Metatarsal Head

Fig. 04b3. Scarf and 1st metatarsal head blood supply.

The scarf cuts preserve both the dorsal and the plantar metatarsal head blood supply.

Fig. 04b3. Scarf and 1st metatarsal head blood supply.

The scarf cuts preserve both the dorsal and the plantar metatarsal head blood supply.

First Metatarsal Medial Approach

We emphasize the following points:

- Preservation of the MTP dorsal capsule to keep the distal cut just proximal thus extra articular while preserving the dorsal blood supply.

- Preservation of the plantar vascular bundle.

- The proximal plantar exposure (ppe) is really the best approach to guarantee an accurate and harmless longitudinal cut and proximal transverse cut. The proximal fixation and the Ml shortening resection are easily performed through this approach.

Scarf Osteotomy Instrument

Fig. 05a. Scarf osteotomy: the medial approach - 1. Distally.

1, 2. The medial approach must preserve the dorsal capsule (dc) to preserve the dorsal blood supply and to keep the distal cut extra articular (2).

3. Minimal exostosis resection, in line with the medial border, just enough to facilitate the medial longitudinal scarf cut.

4. The plantar vascular bundle (pvb) must also be preserved, located between the distal approach and the proximal plantar exposure (ppe).

Fig. 05a. Scarf osteotomy: the medial approach - 1. Distally.

1, 2. The medial approach must preserve the dorsal capsule (dc) to preserve the dorsal blood supply and to keep the distal cut extra articular (2).

3. Minimal exostosis resection, in line with the medial border, just enough to facilitate the medial longitudinal scarf cut.

4. The plantar vascular bundle (pvb) must also be preserved, located between the distal approach and the proximal plantar exposure (ppe).

Fig. 05b. Scarf osteotomy medial approach - 2. Proximally: The Proximal Plantar Exposure (ppe).

1.5 centimeter proximally from the metatarsal head medial cartilage, the scalpel divides the thin septum joining the abductor muscle to the medial border (mb), enabling the ppe which is an important landmark for the scarf osteotomy. The spatula easily separates plantarly from the plantar metatarsal surface (ps), the abductor and the medial head of the flexor hallucis brevis muscles as well as the plantar arteries. There are four advantages of the ppe:

1. To point out the medial border (mb) of the 1st metatarsal, which is an important landmark to perform the longitudinal cut on the medial face.

2. To see the plantar surface of the metatarsal, ensuring first to perform the longitudinal cut (lc) parallel and located just above the metatarsal plantar surface, secondly to make an accurate and safe proximal transverse cut (ptc).

3. To see and control the exit of the K wire for the proximal fixation (5).

4. To pull easily and harmlessly the plantar fragment for 1st metatarsal shortening (6).

Fig. 05b. Scarf osteotomy medial approach - 2. Proximally: The Proximal Plantar Exposure (ppe).

1.5 centimeter proximally from the metatarsal head medial cartilage, the scalpel divides the thin septum joining the abductor muscle to the medial border (mb), enabling the ppe which is an important landmark for the scarf osteotomy. The spatula easily separates plantarly from the plantar metatarsal surface (ps), the abductor and the medial head of the flexor hallucis brevis muscles as well as the plantar arteries. There are four advantages of the ppe:

1. To point out the medial border (mb) of the 1st metatarsal, which is an important landmark to perform the longitudinal cut on the medial face.

2. To see the plantar surface of the metatarsal, ensuring first to perform the longitudinal cut (lc) parallel and located just above the metatarsal plantar surface, secondly to make an accurate and safe proximal transverse cut (ptc).

3. To see and control the exit of the K wire for the proximal fixation (5).

4. To pull easily and harmlessly the plantar fragment for 1st metatarsal shortening (6).

The Scarf Cuts

The osteotomy is designed to separate a proxi-mally based dorsal fragment, which must be handled carefully, especially on the lateral side, and a plantar fragment, which comprises the plantar surface and the metatarsal head. The longitudinal cut is then followed by two transverse cuts.

Longitudinal Cut

The longitudinal cut is first performed on the M1 medial aspect, with accurate specificities following the type of displacement osteotomy requires.

Then the longitudinal cut is made transver-sally across the metatarsal.

The proximal plantar exposure enables this cut to be performed parallel to and located just above the medial plantar surface, therefore isolating the plantar cortex. This cut is oblique laterally and plantarward; it reaches and cuts the lateral surface near its plantar border. This has two results: (1) Lowering of the plantar head fragment when it is laterally displaced; and (2) preservation of the lateral surface, which acts as a strong sagittal strut which allows a large lateral shift of the plantar fragment.

The length of the longitudinal cut.

I know that some authors, like L. S. Weil, adapt the cut length to the degree of defor mity, making a short cut (middle shaft) in mild hallux valgus, and a long cut in case of advanced hallux valgus or osteoporotic bones. I also make this distinction, but I prefer reserving the short cut only for very mild deformity in young patients with a strong bone, particularly to avoid secondary fractures. It is not more invasive to perform a 1 or 1.5 cm longitudinal cut, thus I prefer to reach proximally the cancellous bone of the proximal metaphy-seal, for having two strong pillars, both distal and proximal [131].

Scarf Lengthening Osteotomy

Fig. 06a1. Longitudinal cut on the medial surface.

The longitudinal cut is first performed on the medial surface. There are two important landmarks to perform this cut: 1, 4. The medial border (mb) - correctly pointed out by performing the proximal plantar exposure -and the medial surface of the metatarsal head after performing an economic exostosis resection.

2. Location, proximal and distal ends of the longitudinal cut performed on the medial dorsal surface.

3. The saw blade has a slight proximal direction.

5. Regarding the metatarsal axis (m.ax) the longitudinal cut is oblique so that the solidity of the dorsal fragment is preserved and the cut is longitudinal (so that there is no elevation when shortening: see Fig. 07f5).

Fig. 06a1. Longitudinal cut on the medial surface.

The longitudinal cut is first performed on the medial surface. There are two important landmarks to perform this cut: 1, 4. The medial border (mb) - correctly pointed out by performing the proximal plantar exposure -and the medial surface of the metatarsal head after performing an economic exostosis resection.

2. Location, proximal and distal ends of the longitudinal cut performed on the medial dorsal surface.

3. The saw blade has a slight proximal direction.

5. Regarding the metatarsal axis (m.ax) the longitudinal cut is oblique so that the solidity of the dorsal fragment is preserved and the cut is longitudinal (so that there is no elevation when shortening: see Fig. 07f5).

Sagittal Bunionectomy

Fig. 06a2. Longitudinal cut crossing the metatarsal transversally.

1, 2, 3. The ppe allows to perform this cut accurately. It has to be parallel to the very oblique plantar surface, and located just above. This has two consequences:

Almost the entire lateral surface (ls) is preserved and this strong beam enables a large lateral shift of the plantar fragment while preserving the solidity (a).

The plantar obliquity of the cut results in metatarsal head lowering (b) when laterally displaced.

Fig. 06a2. Longitudinal cut crossing the metatarsal transversally.

1, 2, 3. The ppe allows to perform this cut accurately. It has to be parallel to the very oblique plantar surface, and located just above. This has two consequences:

Almost the entire lateral surface (ls) is preserved and this strong beam enables a large lateral shift of the plantar fragment while preserving the solidity (a).

The plantar obliquity of the cut results in metatarsal head lowering (b) when laterally displaced.

For this reason, I don't agree with a short osteotomy when it is performed in every case by certain authors like Zygmunt et al., Day et al., Reed, Glick-man and Zahari [63], Maestro et al., though the short scarf should be preferable to a long cut distal chevron osteotomy, because the short scarf has two chevrons, proximal and distal, which provides more stability than only a distal one.

Fig. 06a3. Longitudinal oblique cut. Particular aspect.

Since the longitudinal cut is very oblique plantarly, care has to be taken not to begin this cut distally in the middle part of the medial surface of the head (b). This may jeopardize the plantar and lateral surface of the MTP > joint and the lateral sesamoid leading sometimes to a MTP fusion (2, 3): pictures communicated by P. Rippstein, Zurich. We must begin the cut very dorsally on this medial aspect (a).

Fig. 06a3. Longitudinal oblique cut. Particular aspect.

Since the longitudinal cut is very oblique plantarly, care has to be taken not to begin this cut distally in the middle part of the medial surface of the head (b). This may jeopardize the plantar and lateral surface of the MTP > joint and the lateral sesamoid leading sometimes to a MTP fusion (2, 3): pictures communicated by P. Rippstein, Zurich. We must begin the cut very dorsally on this medial aspect (a).

Fig. 06a4. Longitudinal cut: long or short cut?

1, 2, 3. A short cut is almost only indicated for young patient with mild deformity. For moderate or large deformity this cut weakens the osteotomy by being placed at a stress riser and could result in a stress fracture (3). It is also indicated just for DMAA correction (without lateral shift).

4, 5. Only a long cut allows to have two solid fragmental contacts in both the distal and the proximal cancellous bone of the 1st metatarsal. This avoids particularly the "channel effect" in an osteoporotic shaft. In fact, we preserve too strong pillars located in the distal and the proximal cancellous bone of the metatarsal, like in the Bordeaux "Pont de Pierre" (6).

Fig. 06a4. Longitudinal cut: long or short cut?

1, 2, 3. A short cut is almost only indicated for young patient with mild deformity. For moderate or large deformity this cut weakens the osteotomy by being placed at a stress riser and could result in a stress fracture (3). It is also indicated just for DMAA correction (without lateral shift).

4, 5. Only a long cut allows to have two solid fragmental contacts in both the distal and the proximal cancellous bone of the 1st metatarsal. This avoids particularly the "channel effect" in an osteoporotic shaft. In fact, we preserve too strong pillars located in the distal and the proximal cancellous bone of the metatarsal, like in the Bordeaux "Pont de Pierre" (6).

The Transverse Cuts

They are chevron shaped, 60° to the longitudinal cut. Both cuts are directed proximally to allow easier lateral displacement. The proximal cut is performed first in order not to jeopardize the distal fragment when performing the proximal cut.

The proximal cut is accurately and harmlessly performed thanks to the PPE. The distal cut is directed less proximally than the proximal cut to obtain good distal contact between the two fragments; it is performed just proximally to the dorsal capsule, thus remaining extra articular.

Once the cuts are performed, the two fragments become separated. If they are not, we recommend to cross over the saw cut and gently lever the proximal transverse cut with a spatula (Fig. 06b).

Chevron Osteotomy

Fig. 06b. Transverse cuts.

The scarf is a bi-chevron osteotomy. So the transverse cuts form an angle of about 60° with the longitudinal cut (1). Both cuts are directed backwards, but the proximal one is slightly more inclined in order to ensure the distal fragments good contact (2).

- Proximal cut: (3, 4) direction and inclination of the saw blade. The proximal cut is easily performed and checked thanks to the ppe, which also allows protection of the soft tissue (5).

- Distal cut: (6, 7) this cut is just proximal to the dorsal capsule (dc), thus remaining extra articular. This is important for preserving both the MTP range motion and the dorsal blood supply.

Fig. 06b. Transverse cuts.

The scarf is a bi-chevron osteotomy. So the transverse cuts form an angle of about 60° with the longitudinal cut (1). Both cuts are directed backwards, but the proximal one is slightly more inclined in order to ensure the distal fragments good contact (2).

- Proximal cut: (3, 4) direction and inclination of the saw blade. The proximal cut is easily performed and checked thanks to the ppe, which also allows protection of the soft tissue (5).

- Distal cut: (6, 7) this cut is just proximal to the dorsal capsule (dc), thus remaining extra articular. This is important for preserving both the MTP range motion and the dorsal blood supply.

The Displacements

The Versatility of the Scarf Osteotomy

The scarf technique allows a considerable choice of final positions of the fragments. The main displacements, however, are in the transverse plane, mainly lateral shift and if necessary with medial rotation (DMAA or PASA correction). In the frontal plane, lowering, and in the sagittal plane, shortening can be performed if required.

Transverse Lateral Shift

There can be a considerable amount of lateral shift (two-thirds to three-fourths of the surface), because a strong lateral strut is preserved. This is what differentiates the scarf technique form other osteotomies.

To obtain such a large lateral shift, simply pushing the plantar head fragment is insufficient. To "pull and push" is necessary, combining the pushing of the plantar fragment with the medial pulling of the dorsal fragment using a Backhauss clamp (one of the ancillary instruments). The amount of lateral shift depends on the degree of deformity, although the exact amount of the displacement cannot be determined preoperatively.

The lateral shift is the common denominator of the scarf osteotomy for hallux valgus correction. To improve this correction, however, it has to be combined with other displacements.

Healed Scarf Osteotomy

Fig. 07a1. Scarf lateral shift: generalities.

Thanks to the preservation of the lateral surface (ls), the scarf enables a very large lateral shift of the plantar fragment while preserving the solidity. This is a significant improvement for the correction of a large hallux valgus deformity.

Fig. 07a1. Scarf lateral shift: generalities.

Thanks to the preservation of the lateral surface (ls), the scarf enables a very large lateral shift of the plantar fragment while preserving the solidity. This is a significant improvement for the correction of a large hallux valgus deformity.

Hallux Valgus Deformity

Fig. 07a2. Scarf lateral shift: operative views.

1, 2. "Pull and push". 1. Pushing the plantar fragment laterally is not sufficient to achieve a large displacement.

2, The use of a Backhauss clamp (bc) is often necessary to pull the dorsal fragment while pushing the plantar one. This is the "pull and push" motion.

3, 4, 5. We can have more than "half a head" lateral shift and it can be performed not only when the metatarsal is large (4) but also when it is narrow (5).

Fig. 07a2. Scarf lateral shift: operative views.

1, 2. "Pull and push". 1. Pushing the plantar fragment laterally is not sufficient to achieve a large displacement.

2, The use of a Backhauss clamp (bc) is often necessary to pull the dorsal fragment while pushing the plantar one. This is the "pull and push" motion.

3, 4, 5. We can have more than "half a head" lateral shift and it can be performed not only when the metatarsal is large (4) but also when it is narrow (5).

How To Reduce Acne Scarring

How To Reduce Acne Scarring

Acne is a name that is famous in its own right, but for all of the wrong reasons. Most teenagers know, and dread, the very word, as it so prevalently wrecks havoc on their faces throughout their adolescent years.

Get My Free Ebook


Responses

Post a comment