2 The procedure
2.1.1 In hallux valgus the big toe is deviated towards the other toes and a bony protrusion (a bunion) is formed by medial deviation of the first metatarsal phalangeal joint. There may be damage to the skin over the bunion, pain when walking, cosmetic concerns and difficulty with footwear.
2.1.2 Conservative treatment may include footwear modification, and use of insoles or toe spacers. Common surgical treatment options involve different types of first metatarsal osteotomy.
2.2.1 Surgical correction of hallux valgus using minimal access techniques is carried out with the patient under local or general anaesthesia and with X-ray or endoscopic monitoring. One or more small incisions are made close to the hallux metatarsophalangeal joint. The bunion is removed and the metatarsal is divided surgically. The bone fragments may be stabilised using plates, screws or wires. A dressing or plaster may be used to support the foot in the corrected position until the divided bone heals.
Sections 2.3 and 2.4 describe efficacy and safety outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview.
2.3.1 The evidence relates to studies that varied in osteotomy technique (regarding the location, shape and fixation of the osteotomy, and in the methods of visualisation or guidance). Where bone fixation was undertaken, it was usually with Kirschner wires, but use of plates and screws were also reported.
2.3.2 Recurrence of hallux valgus was reported in 2% (2/94) and 1% (1/118) of treated feet in case series of 83 and 82 patients respectively (timing of events not stated).
2.3.3 In a case series of 204 patients (301 feet), 83 reported preoperative pain. Of these, 84% (70/83) reported no pain after the operation, 8% (7/83) had decreased pain and 1% (1/83) had increased pain (mean follow-up 8.3 months). A series of 64 patients reported that 95% (61/64) of patients were pain free at a mean follow-up of 9 years.
2.3.4 Case series of 204 and 168 patients reported postoperative decreases in mean hallux angle from 26° to 7.5° (p < 0.05) and 28° to 14° (significance not stated) at mean follow-up of 6 weeks and 31.5 months respectively.
2.3.5 The case series of 204 patients (301 feet) reported that 74% (61/83) of survey respondents were very pleased with the procedure, 12% (10/83) were somewhat pleased, 4% (3/83) were not satisfied and 4% (3/83) regretted having had surgery (mean follow-up 8.3 months).
2.3.6 The Specialist Advisers listed key efficacy outcomes as improvement in pain and deformity, patient satisfaction, radiographic correction of deformity and pedobarography (foot pressure measurement).
2.4.1 Deep infection at the osteotomy site was reported in 1 patient (treated by intravenous antibiotics and resolved within 2 weeks) in the case series of 82 patients; 1 patient (Kirschner wire removed after 3 weeks and infection resolved) in a series of 31 patients; and in 4% (4/98) of feet in the series of 64 patients (98 feet).
2.4.2 Osteonecrosis was reported in 8% (1/13) of patients in a case series of 13 patients (13 feet) (timing of event not stated).
2.4.3 Delayed union was reported in 1% (4/301) of feet in the case series of 204 patients (301 feet) (at mean 8.3 month follow-up). A case series of 49 patients (59 feet) reported malunion and nonunion in 2 patients each (assessed radiographically at mean follow-up 31.5 months).
2.4.4 Postoperative hallux varus was reported in 0.3% (1/301) (not otherwise described) and 1% (1/94) (1 year after surgery, treated by extensor hallucis longus transfer) of feet in case series of 204 (301 feet) and 83 (94 feet) patients respectively.
2.4.5 Stress fracture of the second metatarsal was reported in 2% (7/301) of feet in the case series of 204 patients (timing of events not stated).
2.4.6 Specialist Advisers expressed concerns about the safety of this procedure. They listed possible adverse events as nerve injury including complex regional pain syndrome, toe stiffness, skin necrosis, osteomyelitis, deep vein thrombosis, tendon injury, removal of fixation screw, recurrent deformity, fracture, tender scars and skin sensitivity. They considered theoretical adverse events to include burning soft tissue, damage to foot blood vessels, inflammatory reaction to bone debris, and first metatarsal malpositioning, shortening or necrosis.