Modified Youngswick Procedure for Hallux Limitus.

Philip Radovic, DPM
Ekta Shah, DPM
Ki Choe, DPM

Multiple surgical procedures have been described for the correction of hallux limitus deformity. We provide a detailed technique on a new modification of the Youngswick procedure for the surgical treatment of hallux limitus. In addition, a brief review of other procedures for hallux limitus are also discussed. The Modified Youngswick procedure will provide a new approach to address hallux limitus secondary to a metatarsus primus elevatus when shortening of the first metatarsal is not indicated.

INTRODUCTION

Numerous etiologies for hallux limitus have been proposed. Pes planovalgus deformity, uncompensated forefoot varus deformity, long first ray, hypermobile first ray or elevated first ray, trauma, arthrosis, and paralytic deformities are just a few.1-6 It has been quantitatively demonstrated that the influence of the first metatarsophalangeal joint (MTPJ) range of motion is dependent on the position of the first ray.7 According to Roukis et al7 by dorsiflexing or elevating the first ray from weight-bearing resting position by 4.0 mm decreased first MTPJ range of motion by 19% and with 8.0 mm of elevation range of motion was decreased by 34.7%. He also demonstrates that an elevated first metatarsal seen in hallux rigidus is greater than that seen with other pathologies such as hallux valgus, plantar fasciitis or Morton�s neuroma.8Several surgical procedures exist for the correction of hallux limitus/rigidus. Cheilectomy, Watermann-Green, Valenti, and Youngswick-Austin are examples of joint preserving procedures while the Keller arthroplasty, first MTPJ implants, and arthrodesis are joint destroying procedures utilized for non-salvageable joints.2-4, 8,9

Our surgical technique is a joint preserving procedure for hallux limitus.A Cheilectomy is an excision of the overlying osseous proliferation on the MTPJ. Though it is easily performed and allows for increased joint motion, it does not correct the underlying cause of the hallux limitus deformity in many cases. The Valenti also offers increase range of motion; it is a more aggressive procedure resecting the dorsal aspect of the joint in �V� fashion (proximal dorsal to distal plantar at the metatarsal head and distal dorsal to proximal plantar on the proximal phalanx base).

This procedure also does not correct the underlying deformity in many cases such as an elevatus. The Watermann-Green and the Youngswick-Austin address the elevated first metatarsal. With these procedures, the capital fragment is plantarflexed but along with the sagittal plane correction, shortening of the first metatarsal is also noted. According to Gerbert10 an advantage of the Youngswick-Austin is correction for an abnormally long first metatarsal. The authors believe that an elevated first metatarsal is not always accompanied with a long first metatarsal. The Modified Youngswick procedure is an excellent alternative to the Youngswick-Austin procedure when an elevated yet a normal to short first metatarsal is present. It is indicated for a hallux limitus stage I or II from Drago et al9 classification system with a positive Seiberg index and a normal to short first metatarsal.

PROCEDURE

A linear longitudinal incision is placed on the dorsomedial aspect of the first MTPJ. Through the same incision a linear longitudinal capsulotomy is performed. The capsule is carefully dissected from the head of the metatarsal and base of the proximal phalanx allowing adequate visualization of the MTPJ. The medial eminence along with any hypertrophic bone growth and osteophytes are resected. Sesamoidal apparatus is inspected and released appropriately if misaligned. A McGlamry elevator is utilized to free adhesions and mobilize soft tissue plantarly.A �V� type of osteotomy is created in the head of the metatarsal with the apex distal and the dorsal arm proximal at approximately 60-degrees measured from the reference line up and plantar arm proximal at approximately 30-degree measured from the reference line down (Fig 1,2).

A parallel osteotomy to the dorsal arm is made creating a predetermined segment of bone. This segment is set aside and will later serve to maintain the metatarsal length and add stability to the reduction.The capital fragment is distracted and plantarflexed on the metatarsal shaft correcting the sagittal plane deformity. Shifting the capital fragment laterally will allow for transverse plane correction if necessary.

The segment of bone from the dorsal cut is retrieved and placed plantarly into the osteotomy gap (Fig 3). A 0.045-inch k-wire is then utilized as temporary fixation across the osteotomy site from proximal to distal. Using proper AO technique one or two screws depending on the osteotomy stability and surgeon preference are inserted perpendicular to the osteotomy site from dorsal distal to plantar proximal. The remaining bone self is resected flush to the metatarsal and a power rasp is utilized to smooth all rough edges. The temporary fixation is removed and the surgical site irrigated.

Capsulorrhaphy may be performed as needed. The capsule is reapproximated with 3-0 vicryl; the subcutaneous tissue with 4-0 vicryl and skin is closed to surgeon�s preference. The surgical site is dressed with sterile compressive dressings.Patients are instructed on minimal weight bearing or heel weight bearing in a post-operative shoe and are followed up in 3-5 days. Serial radiographs are performed and patient is returned to regular shoes in 4-6 weeks depending on trabeculation and healing across the osteotomy and graft.

DISCUSSION

We present a new surgical technique for the correction of hallux limitus with a normal to short, elevated first metatarsal. Gerbert et al11 formulated an equation, B (sin A)=P (B=amount of bone segment, A=plantar arm degree, P=plantar displacement in millimeters) allowing the surgeon to customize the Youngswick osteotomy to the amount of plantar displacement needed. This is the parameter utilized by the authors for the osteotomy angles presented. The Modified Youngswick, like the Youngswick procedure, allows the surgeon to address the elevatus commonly attributing hallux limitus and applies Gerbert�s equation.

By placing the bone segment into the plantar osteotomy, unlike the Youngswick, the length of the metatarsal remains the same. In the early stages of hallux limitus, an indication for the Modified Youngswick, minimal or no joint involvement is noted and shortening the metatarsal to reduce internal cubic content is not necessary. By using predetermined osteotomy angles and bone segment and placing it plantarly into the osteotomy, we are able to maintain the length while plantarflexing the capital fragment (Fig 4 A-D). The capital fragment is plantarflexed without proximal displacement and thus creates a gap plantarly for the bone segment.

Once the bone segment is added a more stable interface between the capital fragment and the metatarsal is created along with resistance to dorsal displacement.The surgeon must also keep in mind that normal metatarsal protrusion distance is +/- 2 mm and approximately 1 mm shortening occurs with each pass of the blade with any osteotomy. Thus, shortening osteotomies of the first metatarsal in hallux limitus are not always necessary and can lead to complications including alterations to the metatarsal parabola and increased risk of metatarsalgia,12 second MTPJ pre-subluxation syndrome, and/or capsulitis. Transfer metatarsalgia and/or transfer lesions are common complications from first metatarsal shortening seen in the Youngswick procedure.13 Kilmaritin12 found 1 in 3 patients developed matarsalgia after decompressional osteotomies. Shortening osteotomies can also lead to progressive instability of the medial column.13 The Modified Youngswick procedure minimally influences the metatarsal parabola thus reducing lesser metatarsal sequelae.

CONCLUSION

The Modified Youngswick procedure is a practical approach to the surgical management of hallux limitus grades I or II. The procedure realigns the MTPJ and increases range of motion without affecting the length of the metatarsal. The authors have noted excellent results with an increase in the range of motion of the first MTPJ. Good stability was noted along with no incidence of delayed healing when compared to the Youngswick procedure. Patient based studies utilizing the modified Youngswick procedure as a treatment for type I and/or II hallux limitus are in progress. The quantitative increase in range of motion along with post-operative sequelae are being evaluated.

REFERENCES

FIGURE LEGENDS

Figure 1. Lateral view of the first metatarsal. A, Reference line parallel to weight-bearing surface. B, 60-degree dorsal arm from reference point. C, 30-degree plantar arm from reference point. D, Bone segment to be removed. Figure 2. Removal of predetermined bone segment from dorsal osteotomy. Figure 3. Placement of bone segment into plantar osteotomy gap. Figure 4 A-D. A, Lateral radiograph template demonstrating first metatarsal length of 62mm. B, The dotted line represents the axis line used to create a dorsal arm of 60-degrees and a plantar arm of 30-degrees. C, A predetermined wedge is removed from the dorsal arm and placed into the plantar arm after plantarflexing the capital fragment. D, First metatarsal length of 62mm maintained while capital fragment plantarflexed.