Scarf Procedure and Rotational Scarf Procedure

Fig. 12.1

Demonstration of the Jupiter cut in a market in Auvillars (Haute Garonne), France

Fig. 12.2

Depiction of the long inter-fragmental contact and the double chevron cut distal dorsal and proximal plantar on a cadaveric model of the first metatarsal

The debut of the Z-cut osteotomy in 1976 by Burutaran of San Sebastian, Spain, was performed in conjunction with the Keller arthroplasty for primary bunion correction [2, 9]. This osteotomy was revised, by Gudas and Zygmunt in 1982 with a full-length horizontal “Z” cut in the mid-shaft of the first metatarsal with a 50/50 transverse osteotomy [1]. Continued modifications to the initial “Z” lent itself to the scarf osteotomy originally described by Weil, Sr., in 1984. The scarf osteotomy was an evolution of the “Z” and incorporated a more distally cancellous cut in the metaphyseal head of the first metatarsal and more proximal cut at the metatarsal flare. The distal cut was performed at a 70–90° angle to avoid the fragility of a more angular osteotomy and to maintain the cut in the denser and stable metaphyseal bone. The cuts were made distally at the dorsal one-third of the metatarsal and proximally at the plantar one-third of the metatarsal. All of these alterations lead to the ability for increased correction while preventing the most common limitations seen in literature [2, 8, 11]. This powerful osteotomy gained increasing popularity with the publications and long-term follow-up by Barouk and Weil et al. [2, 7].

Frontal plane correction has been discussed since the early 1980s, and recent advancements with frontal plane rotation have altered thoughts and imparted a new component to bunion correction [3–6]. Triplanar deformities can be corrected if deemed necessary, with the preoperative and intraoperative confirmation, by performing a rotational scarf osteotomy . By performing this de-rotational osteotomy, there is no loss of corrective power within the transverse or sagittal plane.

Indications

The scarf osteotomy has been shown to correct intermetatarsal (IM) angle up to 23°, proximal articular set angle (PASA) of 10°, and a hallux interphalangeus angle as high as 35° with additional adjunctive procedure of an Akin osteotomy [2, 10]. Indications for the scarf bunionectomy are:

1.

IM angle of 12–23°
2.

True IM angle greater than 12°
3.

Minimal to no arthritic changes at the first metatarsophalangeal joint with at least 40° of dorsiflexion

Preoperative Imaging

All patients are evaluated clinically and corroborated with bilateral weight-bearing radiographs: consisting of anterior-posterior (AP), lateral (LAT), sesamoid axial (SA), and oblique views. All foot radiographs should be weight bearing, especially if evaluating hallux valgus deformity to fully appreciate the pathology. The AP weight-bearing view is utilized to assess the hallux valgus angle (HA), first and second IM angle, metatarsal parabola, metatarsus adductus (MA) angle, and tibial sesamoid position (TSP). Other angles that can be observed on weighting bearing AP radiographs include distal articular set angle and hallux interphalangeal angle (Fig. 12.3). The evaluation of sagittal plane deformity such as declination or metatarsus elevatus is observed on lateral weight-bearing films and should be accounted when determining appropriate surgical care (Fig. 12.4). In conjunction with the TSP on weight-bearing AP films, the sesamoid axial can assist in determining any frontal plane deformity of the metatarsal as well as establish the sesamoid position in relation to the crista (Figs. 12.5 and 12.6). Radiographs, clinical exam, and appreciation of patient’s goals are necessary to determine the best treatment and surgical intervention. Advanced imaging studies such as MRI and CT provide little additional information to the initial workup, although many have described use of 3D weight-bearing CT imaging as a beneficial imaging exam, and this is an evolving area that may have greater future benefits .

Fig. 12.3

The AP weight-bearing view is utilized to assess the hallux valgus angle (HA), first and second IM angle, metatarsal parabola, metatarsus adductus (MA) angle, and tibial sesamoid position (TSP). Other angles that can be observed on weight-bearing AP radiographs include distal articular set angle and hallux interphalangeal angle

Fig. 12.4

The evaluation of sagittal plane deformity such as declination or metatarsus elevatus is observed on lateral weight-bearing films and should be accounted when determining appropriate surgical care

Fig. 12.5

The sesamoid axial can determine any frontal plane deformity of the metatarsal as well as establish the sesamoid position in relation to the crista; there is no frontal plane deviation in this preoperative weight-bearing X-ray

Fig. 12.6

There is a frontal plane deviation in this preoperative weight-bearing X-ray, determined by the position of the crista

Surgical Technique

The scarf osteotom y is performed through a medial incision. The medial incision is preferred as it is void of neurovascular structures, allows better visualization and leads to better postoperative cosmetic result (Figs. 12.7 and 12.8). The incisional approach is medial at the junction of the plantar and dorsal skin extending 5–7 cm from the base of the proximal phalanx to the mid-segment of the first metatarsal shaft, paying careful attention to the 15-degree declination of the metatarsals (Fig. 12.9).

Fig. 12.7

Preoperative clinical image, non-weight bearing showing substantial deviation of the first metatarsal with drifting of the great right toe. Skin markings seen are for adjunctive procedures: plantar plate repair of the second as well as an exostectomy of the IPJ of the hallux

Fig. 12.8

Preoperative clinical image, non-weight bearing. Skin markings demonstrated a 5–7 cm linear marking coursing along the declination of the first metatarsal. This incision is extended over the base of the proximal phalanx if an osteotomy is indicated

Fig. 12.9

The skin incision is deepened through subcutaneous tissue

After the skin incision is deepened through subcutaneous tissue, the great toe is dorsiflexed to reveal a dorsal pocket to allow for dissection deep to the neurovascular bundle allowing for retraction and protection (Fig. 12.10). Next, the great toe is plantarflexed, which exposes a pocket at the most distal plantar aspect of the joint to carefully release soft tissue attachments from the capsule (Fig. 12.11). The use of single prong urologic skin hooks provides less traumatic handling of the dorsal and plantar skin and excellent exposure (Fig. 12.12).

Fig. 12.10

Using the non-dominant hand, the great toe is dorsiflexed to reveal a dorsal pocket to allow for dissection under the neurovascular bundle to allow retraction without disturbance

Fig. 12.11

Using the non-dominant hand, the great toe is plantarflexed which exposes a pocket at the most distal plantar aspect of the joint. This pocket demarcates to permit careful release of all soft tissue attachments surrounding the joint capsule

Fig. 12.12

Four single prong urologic skin hooks, two dorsal and two plantar, provide less traumatic handling of the dorsal and plantar skin and excellent exposure. They are held taught on the opposing side of the foot with a heavy hemostat

A lenticular capsular incision is then performed, excising a fusiform-shaped portion of capsule at the level of the first metatarsal head (Fig. 12.13). This resection is not performed over the joint in order to prevent postoperative scarring, which could result in limitation of motion. The capsule and periosteum are reflected dorsally and plantarly to expose the metatarsal for osteotomy and fixation. To minimize soft tissue trauma and ensure the osteotomy can be translocated, the handle of the #3 Bard-Parker blade is utilized to free the proximal plantar soft periosteum under the proximal first metatarsal (Figs. 12.14 and 12.15) [17, 18].

Fig. 12.13

A lenticular capsular incision is then performed with a #15 blade; this ellipse is initiated from proximal to distal and is carefully performed not to extend over the joint

Fig. 12.14

To minimize soft tissue trauma and ensure the osteotomy can be displaced, the handle of the #3 Bard-Parker blade is utilized to free the proximal plantar soft periosteum under the first metatarsal

Fig. 12.15

The orientation is directed from distal medial to proximal lateral along the contour of the base of the first metatarsal

An intra-articular sesamoid release is performed through the same incision with the use of a McGlamry elevator releasing the lateral suspensory ligament (Fig. 12.16). Through this approach, the blood supply to the first metatarsal and sesamoid apparatus is not compromised, and an adjuvant incision in the first interspace is not required (Figs. 12.17, 12.18, and 12.19) [17, 18]. This technique allows for mobilization of the sesamoid apparatus and preservation of the lateral metatarsophalangeal joint ligament, thereby maintaining stability of the joint. Manual manipulation of the great toe into extreme varus, keeping the metatarsal head within the soft tissue, should be performed to confirm a full ligament release (Fig. 12.20) [2, 12].

Fig. 12.16

An intra-articular sesamoid release is then performed through the same incision with the use of a McGlamry elevator releasing the lateral suspensory ligament

Fig. 12.17

Arterial supply to the first metatarsal head

Fig. 12.18

Plantar arterial supply to the first metatarsal head

Fig. 12.19

Plantar arterial supply and dorsolateral system of the first metatarsal head

Fig. 12.20

Manual manipulation of the great toe into extreme varus, keeping the metatarsal head within the soft tissue, should be performed to confirm a full ligament release

Frontal plane rotation of the first metatarsal is evaluated by assessment of the joint and compared with the preoperative sesamoid axial views. If there is no rotational deformity, a standard scarf osteotomy will be performed; however, if there is a rotational component, an additional step will be added to the standard scarf procedure.

Standard Scarf Osteotomy

Prior to making any osteotomy, a smooth 0.045 Kirschner (K) wire is placed as an apical axis guide. The apical pin is placed in the dorsal one-third to one-fourth of the head of the first metatarsal to safeguard appropriate placement of the dorsal apex arm of the osteotomy (Figs. 12.21, 12.22, and 12.23). This ensures that the distal aspect of the osteotomy will be in the cancellous bone and not the more fragile corticomedullary bone, increasing stability and preventing the troughing effect. In addition, the osteotomy is angulated 15–30° plantarly so plantar displacement of the first metatarsal head is achieved with lateral translation and intermetatarsal correction of the capital fragment. This creates increased medial column stability and reduces the possibility of transfer metatarsalgia (Fig. 12.20).