патогенез hallux valgus

Surgery for Hallux Valgus

Recovery and Rehabilitation

After the operation, you will need to remain non-weight bearing with your foot elevated for the first two to three days.

After this time you will need to wear a special shoe that shifts your weight away from your large toe. This usually continues for around 6 weeks, but during this time you can put your full weight through the foot.

You will start seeing a physiotherapist who will show you a number of exercises to maintain the flexibility of your joint. These will gradually progress into full strengthening and range of motion exercises over the weeks of your rehabilitation.



Hallux Valgus Osteotomy

Pre-Procedure

Background

Hallux valgus is a deformity at the base of the big toe or the metatarsophalangeal joint in which the great toe or hallux is deviated or points toward the lesser toes; in severe types of the deformity, the great toe goes over or under the second toe.

The musculotendinous attachments in the great toe bypass without any attachment to the head of the metatarsal itself to be inserted into base of the proximal and distal phalanges. When the great toe is in a normal alignment, the muscle forces exerted around it are balanced. Deformity is associated with muscle imbalance at the metatarsophalangeal joint. The muscle imbalance increases with the deformity; in long-standing hallux valgus deformity, a contracture in the overpowering lateral muscles and stretching of the medial capsule exists. As the deformity increases, the metatarsal head becomes prominent medially giving rise to the "bunion" deformity.

A number of operative procedures and osteotomies have been devised and or modified over the years. The great variety of procedures and osteotomies devised underlines the fact that all hallux valgus deformities are not similar and no single versatile osteotomy can treat them all. Therefore, exact procedure(s) selected for operative intervention is based on carefully clinical and radiological evaluation and planning.

Decision making requires careful consideration of the following:

History: patients age/duration and severity and location of pain/involvement of other joints/response to conservative care/activity level/occupation/expectations

Comorbidities: diabetes mellitus/rheumatoid arthritis/gout/stroke or any other underlying spastic neurologic conditions

Physical findings: severity of deformity/presence of bursitis/cellulitis/calluses/rotational deformity or pronation/reducibility of deformity/hyper mobility of the metatarsocuneiform (MTC) and other joints/pes planus/gastrocnemius contracture and neurovascular status

Radiographic evaluation of the hallux valgus, intermetatarsal, and interphalangeal, distal metatarsal articular angles; metatarsophalangeal (MTP) joint congruity; and sesame-metatarsal, MTP, and MTC joint congruity or arthrosis

Relevant Anatomy

The metatarsal bones are roughly cylindrical in form. The body tapers gradually from the proximal to distal end. They are curved in the long axis and present a concave plantar surface and a convex dorsal surface.

The first metatarsal bone is the stoutest and the shortest of the metatarsal bones. The body is strong and of well-marked prismoid form. The base usually has no articular facets on its sides, but occasionally on the lateral side an oval facet exists, by which it articulates with the second metatarsal. Its proximal articular surface is of large size and kidney shaped; its circumference is grooved (for the tarsometatarsal ligaments) and medially gives insertion to part of the tendon of the tibialis anterior; its plantar angle presents a rough, oval prominence for the insertion of the tendon of the fibularis (peroneus) longus. The head is large; on its plantar surface are 2 grooved facets, on which glide sesamoid bones; the facets are separated by a smooth elevation.

For more information about the relevant anatomy, see Foot Bone Anatomy .

Indications

Failure of conservative care to relieve symptoms due to hallux valgus deformity is an indication for consideration of surgical intervention. Some patients worry that the deformity may become worse and therefore prefer it to be corrected. But rapid progression of a hallux valgus deformity is unusual; therefore, the deformity can be observed and decision based mainly on symptoms. Pain and discomfort and failure of conservative measures to relieve symptoms and lifestyle needs should be the major considerations for surgical correction.

Contraindications

Patients should be made to realize that return to professional sports or dance cannot be guaranteed. They must fully understand that some residual stiffness, pain, or deformity may be inevitable. Following surgery, they may not be able to return to their previous level of activity. Therefore, until they can no longer perform in their chosen field, bunion surgery should probably be deferred. If patients can eventually resume their previous level of activity after surgery, they will be much more satisfied with the outcome. [1]

The current opinion and stand by reputed societies such as the American Orthopedic Foot and Ankle Society advise against cosmesis as an indication for surgery. Surgery should not be performed just to enable patients to wear fashionable shoes. Patients who have bunion surgery only because they believe that they will then be able to wear a more fashionable shoe are subsequently disappointed when this goal cannot be achieved. In reviewing more than 300 bunion cases, Coughlin and Jones observed that a third of patients could wear the shoes that they wanted before surgery and that two thirds could after surgery. Unfortunately, this still leaves a third of patients unable to wear their shoe of choice, and this should be explained to the patient who do not have pain but simply want to fit their feet into narrower shoes. [2, 3]

Dysvascular patients with poor vascularity are at risk of wound healing problems and gangrene with loss of toes. Other contraindications include advanced arthrosis of the MTP joint, gout, neuropathy, spasticity of any type (eg, cerebral palsy, CVA, head injury), and ligamentous laxity.

Preparation

Anesthesia

Hallux valgus corrective procedures can be undertaken with a local anesthetic block around the base of the first metatarsal and in first web space or with an ankle block if other toes too need surgical intervention. A calf or ankle level tourniquet can be uncomfortable, and, if required, a popliteal level block is also a suitable alternative. The block can be supplemented by sedation and or alternatively the procedure can be undertaken with laryngeal mask or endotracheal anesthesia depending on patient and anesthesiologist preference.

Regardless of whether the patient receives a general anesthetic or not, the author highly recommends pre-emptive analgesia and anesthetic techniques that are multimodal and give excellent preoperative anesthesia and postoperative pain control, which is an important objective especially for prevention of chronic pain.

On the day of surgery, if no contraindications exist, a cox-2 inhibitor is given in the morning. The author has a motto ("‘needle before knife") and believes that if a mixture of short-acting and long-acting local anesthetic is injected before skin incision, and if oral analgesics are started before the local anesthetic effect wears off in the immediate postoperative interval and are given on a regular basis, the patients go through the entire experience with little or no pain.

Equipment

A tourniquet is traditionally applied at the level of the thigh, but, over the years, tourniquets applied more distally in the leg just above the ankle work just as well and decrease the area that is unnecessarily exsanguinated, thus limiting the reperfusion injury or effects. Also, a distal tourniquet need not be inflated to the same higher level of pressure, and, typically, 250 mm of Hg or 100 mm of Hg higher than the systolic blood pressure is sufficient.

Positioning

Patient is positioned supine with pressure points padded. The author uses a triangle under the knee helps to keep the foot flat on the table and makes orientation easier to follow. [4] The foot is elevated over a double-brick height and shaped bump to clear it from the other limb, allowing unobstructed ease of access to instruments such as the saw or drill and for fluoroscopy. The knee support also stabilizes the limb and lessens the need or reliance on assistance for maintaining position of the limb or the foot.

Complication prevention

Always be aware of the anatomy and location of the neurovascular structures. Careful dissection and retraction of the flaps before execution of the osteotomy is important to prevent soft tissue damage. Also, thermal damage should be avoided by using a low setting on the driver for the saw, irrigation, sharp thin blade with fine teeth and by unclogging the teeth if the same saw is being used.

Technique

Approach

The osteotomies for hallux valgus are performed through a medial approach. A longitudinal incision along the midline at junction of plantar and dorsal skin on the medial border of the foot straddling the metatarsophalangeal joint is marked and carried out using a No. 15 blade. Careful dissection is carried out in the loose areolar tissue plane that is naturally there, created by movement of skin and subcutaneous tissue over the capsular structures. Dissection in this plane is safer and easier and creates full thickness soft tissue flaps superficial to the level of the joint capsule.

The dorsal and plantar flaps thus created carry the dorso-medial and plantar-medial digital nerves and are kept retracted and away from instruments for rest of the procedure. Then the capsule is incised along the line of incision exposing the medial eminence. The proximal and distal extension of the exposure depends on the exposure needed and type of osteotomy planned. The bunion prominence on medial aspect of the head of the metatarsal is excised in line with the medial aspect of the foot. Excessive resection can lead to hallux varus.

Osteotomy

Generally, the more severe the deformity, the more proximal or longer is the osteotomy needed on the first metatarsal and the more likely at more than one levels, such as an additional osteotomy in the proximal phalanx. Selection of a particular osteotomy is also dependent on familiarity and experience of the surgeon. For mild deformities, a distal metatarsal osteotomy such as a Chevron osteotomy is sufficient. For moderate and severe deformities, a midshaft or proximal osteotomy along with a phalangeal osteotomy may be necessary. The midshaft osteotomies commonly performed are the Z or Scarf osteotomy and the Ludloff osteotomy. A closing or opening wedge osteotomy at base of metatarsal or the cuneiform is also an option for severe deformities. Commonly performed osteotomies are described further below.

Chevron osteotomy

A chevron osteotomy is chevron shaped and is located in the broad metaphyseal region at junction of head and neck. A 0.062" drill hole is useful to mark the apex of the chevron on the metatarsal head. The drill hole is started on the medial surface of the head at or just proximal to the center of an imaginary sphere that is the head of the metatarsal and driven in a direction that is medial to lateral and in line that is parallel to the plantar surface and the articular surface of the head of the metatarsal (see the images below). Then the limbs of the chevron are 2 cuts made by a sagittal saw starting at the hole. The limbs of the chevron cuts extend proximally at a 60 ? angle, the plantar cut exiting the plantar cortex proximal to the sesamoid articulation.

Chevron osteotomy to correct a severe hallux valgus deformity: the deformity on left side and on the right side operated previously. Chevron osteotomy to correct a severe hallux valgus deformity: the preoperative anteroposterior radiograph with patient standing. Chevron osteotomy to correct a severe hallux valgus deformity: the preoperative anteroposterior radiograph with measurements of the hallux valgus and the intermetatarsal angles.

As the osteotomy is performed, irrigation is used to dissipate heat; as the saw blade approaches the lateral cortex care must be taken not to overpenetrate the cortex and enter the lateral soft tissues, to prevent damaging the blood supply to the metatarsal head. Badwey et al reported that the capital fragment can be displaced laterally up to 6 mm in males and 5 mm in females, which constitutes displacement of approximately 30% of the metatarsal's width. [5]

To displace the osteotomy, holding the proximal portion of the metatarsal with a small towel clip while pushing the metatarsal head laterally is sometimes useful. The osteotomy is then fixed with a single K wire. The author uses the K wire as a buttress (see the images below).

Chevron osteotomy to correct a severe hallux valgus deformity: the intraoperative radiograph of anteroposterior and oblique views showing the K–wire being used as a "buttress." Chevron osteotomy to correct a severe hallux valgus deformity: the intraoperative radiograph of lateral views showing the chevron-shaped osteotomy cut and the K-wire.

The tip of the wire is held flat against the displaced head and first brought out distally through a long soft tissue sleeve and the proximal tip of the wire is cut blunt. Holding the displacement the blunt tip is introduced into the shaft of the proximal fragment and advanced proximally by tapping on its distal end until the blunt end lodges securely in the subchondral region at the base of the metatarsal. The excess sharp projection at the displaced distal medial end of the shaft of the first metatarsal is trimmed (see the images below).

Chevron osteotomy to correct a severe hallux valgus deformity: the foot in the follow-up period at 6 weeks and the tip of the K-wire on medial side of the great toe. Chevron osteotomy to correct a severe hallux valgus deformity: the anteroposterior radiograph showing the correction of the deformity and improvement in the hallux valgus and intermetatarsal angles measured. Chevron osteotomy to correct a severe hallux valgus deformity: the lateral radiograph showing the healed chevron osteotomy. Chevron osteotomy to correct a severe hallux valgus deformity: the great toe in an improved alignment compared to the preoperative photograph.

Scarf osteotomy

A scarf osteotomy is an osteotomy with an outline that looks like the letter "z"; it is also called a "z" osteotomy. The metatarsal shaft is essentially split in dorsal and plantar halves. This longitudinal split in shaft extends into the metaphysis distally into the head and proximally in the base but stops short by 1–2 cm from articular surfaces. Transversely directed cuts from medial to lateral in dorsal half distally and in plantar half proximally create 2 segments of the first metatarsal with the plantar half carrying the head segment and the dorsal half carrying the base. The exposure described above is used but extended proximally to expose the medial surface of the first metatarsal.

Osteotomy to correct a severe hallux valgus deformity: the hallux valgus deformity in the left foot. Scarf osteotomy to correct a severe hallux valgus deformity: the preoperative anteroposterior radiograph with measurements of the hallux valgus and the intermetatarsal angles. Scarf osteotomy to correct a severe hallux valgus deformity: the exposure for scarf osteotomy on medial aspect of the foot.

After the resection of the medial eminence, the osteotomy to be executed is drawn out. A 0.045" K wire is drilled 1 cm away from the articular surface of the head, halfway between the dorsal and plantar surface in a medial-to-lateral direction also aimed in about 15 ? plantar and proximal orientation. Another wire is drilled parallel to this wire, again, halfway between the dorsal and plantar surfaces under fluoroscopy to ensure that it is at least 1 cm distal from the articular surface at the base (see the image below).

Scarf osteotomy to correct a severe hallux valgus deformity: the fluoroscopic image and a needle used to determine the proximal extent for the osteotomy.

These wires form the apices of the "z" and limit the cut that is along the long axis of the shaft. A sagittal saw is used to execute the longitudinal cut, again ensuring that the saw blade is directed plantarwards from a medial-to-lateral direction (see the images below).

Scarf osteotomy to correct a severe hallux valgus deformity: the vertical cut and saw blades in the horizontal cuts at either end of the first. Scarf osteotomy to correct a severe hallux valgus deformity: the vertical cut and saw blades in the horizontal cuts at either end of the first metatarsal bone parallel to each other.

At either end of this longitudinal cut another cut is made along the width directed medial to lateral and angled proximally. The distal cut is made dorsal and the proximal cut made plantar to the K wires in this location; additionally, care is taken not to enter the joint at base of the metatarsal. After the osteotomy is conducted, the plantar capital fragment is displaced laterally and the dorsal basal fragment displaced medially to reduce the intermetatarsal angle; additionally, the capital fragment can be rotated out to correct articular set angle by taking appropriate sized medial based wedges at either end. Once the deformity is reduced satisfactorily, as determined clinically and radiologically, the displacement is secured with bone clamps and later with 2 cortical 2.5 mm diameter screws (see the images below).

Scarf osteotomy to correct a severe hallux valgus deformity: the fluoroscopic image of the displacement held with a clamp. Scarf osteotomy to correct a severe hallux valgus deformity: the intraoperative photograph of the corrected hallux valgus deformity. Scarf osteotomy to correct a severe hallux valgus deformity: the anteroposterior radiograph showing the correction of the deformity and improvement in the hallux valgus and intermetatarsal angles measured at 3 months. Scarf osteotomy to correct a severe hallux valgus deformity: the lateral radiograph showing the healed scarf osteotomy and the 2 screws used to stabilize the osteotomy. Scarf osteotomy to correct a severe hallux valgus deformity: the great toe in a improved alignment compared to the preoperative photograph.

Ludloff osteotomy

Ludloff osteotomy is an oblique osteotomy that begins dorsally a few millimeters distal to the joint at the base of the first metatarsal and is directed plantar at a 30 ? angle; it is carried out into the shaft region and stopped just before it exits the plantar surface. A 3.5-mm screw is placed proximally at right angles to the osteotomy, and, before it is countersunk, the rest of the osteotomy is completed. The capital fragment is then rotated with the screw as an axis to reduce the hallux valgus deformity. After the desired correction is obtained and checked clinically and radiologically, the screw is tightened and an additional screw is inserted distal to the first screw to secure the displacement.

Akin osteotomy

An Akin osteotomy is performed at the base of the proximal phalanx. It is a medial-based closing wedge osteotomy. Retracting the flexor hallucis tendon and the extensor tendon dorsally and using fluoroscopy to ensure that the proximal articular surface is not violated is important.

The first cut is made from medial to lateral across the width and is parallel to the base of the proximal phalanx, stopping short of the lateral cortex; the second cut starts just distal to this cut and is aimed to meet the first cut on the lateral cortex, again leaving it weakened but not cut. The wedge-shaped wafer of bone between these 2 cuts is removed. The lateral opening is then closed with the weakened lateral cortex as a hinge. The osteotomy is secured with a K wire driven from plantar medial corner at base of proximal phalanx across the osteotomy into dorsal distal shaft just enough to engage it.

First web space soft tissue release

This is a more appropriate term than the commonly used term "distal soft tissue release," because no "proximal’ soft tissues can be released and because the new term defines the procedure more aptly. It is used to release the contracted lateral structures to allow a subluxed head of the metatarsal to be relocated in the joint (see the image below).

First web space release as an adjunctive procedure to correct a severe hallux valgus deformity: the hallux valgus deformity in the left foot.

This procedure described below uses a new technique and a new approach that is sequential and hidden in the web fold and, therefore, more cosmetic than a dorsal approach, which gives a visible scar on top of the foot. [6] The procedure is performed as follows: With toes held apart, a vertical incision from dorsal to ventral is made in the first web space to include the transverse fold of skin (see the images below).

First web space release as an adjunctive procedure to correct a severe hallux valgus deformity: the incision marked out for an approach that is hidden in the first web space. First web space release as an adjunctive procedure to correct a severe hallux valgus deformity: the deeper tissues exposed delineating the adductor tendon. First web space release as an adjunctive procedure to correct a severe hallux valgus deformity: the capsule incised longitudinally and the head of metatarsal exposed after release of the sesamometatarsal ligament.

Blunt dissection is carried out proximally in the web space to identify the structures while the plantar digital neurovascular bundle is retracted plantarwards using a Langenbeck retractor. The soft tissue structures are identified and then cut in a sequence as follows:

Step 1: The superficial and deep intermetatarsal ligaments are cut using tenotomy scissors.

Step 2: The adductor tendon just proximal to its insertion is outlined and detached at its attachment to the fibular sesamoid.

Step 3: The capsule is incised longitudinally at the level of the metatarsophalangeal joint with a No. 11 blade.

Step 6: Two 2-0 Vicryl sutures are placed in the capsule of the first and second metatarsals and the detached stump of adductor tendon. An assistant holds the forefoot squeezed while the 2 sutures are tied to bring the heads of first and second metatarsals together.

The wound is irrigated and closed using a subcuticular Vicryl suture at this stage or after performing the concomitant procedures planned such as scarf osteotomy of first metatarsal.

A retrospective chart review of 76 patients (88 procedures) and functional outcome analysis of 38 patients (44 procedures) who underwent first web space release using the new technique was conducted by Panchbhavi et al. [7] The mean followup was 3.8 years. The mean age was 50.8 (range, 24 to 74) years; 98% were female patients and 2% were male. Most of the patients (89%) had good or excellent results. The surgical scar was hidden between the first and second toes in the web fold. The average Olerud-Molander score was 86.4 out of 100. None of the patients reviewed had nerve injury, recurrence of deformity, hallux varus, or revision surgery. They conclude that the new technique for the first web space soft tissue release was a reliable technique that can be used as an adjunctive surgical procedure in correction of hallux valgus. Since the incision is in the web fold, the resulting scar is hidden.

Wound Closure

The correction leaves the capsule on the medial surface of the head redundant. The plantar capsular flap is folded into A V-shaped fold, which is raised in the plantar capsular flap. Enough is folded to take up the slack, and it is excised. This leaves a straight vertical cut, which is then repaired using an absorbable suture. The dorsal flap is drawn under the plantar flap and sutured in a pants-over-vest manner using mattress sutures. The rest of the wound is closed using a running non absorbable subcuticular stitch.

A nonadherent dressing is applied next to the wound and then covered with 4x4 gauze pieces. A 2" gauze roll is then rolled in a figure-of-8 manner to include the base of the big toe and forefoot. Then in a similar manner a soft roll of cotton is applied. The aim of the dressing is to ensure that the great toe is held aligned.

A well-padded posterior splint can then be applied for pain relief and protection. Alternatively, a post-operative accommodative shoe with a rocker sole can be used in a reliable patient.