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
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 advice 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.
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