The Scarf Osteotomy with Minimally Invasive Lateral Release for Treatment of Hallux Valgus Deformity: Intermediate and Long-Term Results

SLR - November 2015 - Osayamen Edigin

Podiatric Relevance: Hallux valgus deformity is a common pathology faced by many podiatrists. Conservative and surgical treatments have been described extensively in podiatric and non-podiatric literatures. Amongst the surgical treatments is the 1st metatarsal midshaft osteotomy; more specifically the Scarf osteotomy. This is a powerful procedure used for the correction of hallux valgus deformity. This osteotomy is sometimes performed in combination with a closing wedge osteotomy of the proximal phalanx of the hallux (Akin osteotomy) with additional soft tissues procedures. Adjunctive soft tissue procedures, which include the lateral release, can be accomplished from a dorsal approach through the first intermetatarsal web space, or a single dorsomedial approach, or intra-articular approach. The authors show intermediate and long term results following a minimally invasive lateral release via a dorsal approach and in combination with the Scarf osteotomy.

Methods: This is a retrospective review of 108 patients (115 feet), from January 1997- December 1999, who underwent unilateral Scarf osteotomies with lateral releases via a dorsal skin incision not longer than 0.5cm. Ninety-three patients (93 feet) were evaluated at a mean follow-up of 124 months. Pre-operative and post-operative radiographic and clinical assessments were recorded. Parameters including first intermetatarsal angle (IMA), hallux valgus angle (HVA), the distal metatarsal articulation angle (DMAA), sesamoid position, and first metatarsophalangeal joint range of motion were analyzed and reported by the authors. Inclusion and exclusion criteria were extensively detailed in this paper. Intra-operatively, a Z-shaped Scarf osteotomy was performed from a medial skin incision and fixation was achieved using a single compression screw. A lateral release was performed only if the hallux valgus deformity was not reducible to 10 degree varus position and sesamoid subluxation was present. An adjunctive Akin osteotomy was performed in cases with hallux valgus interphalangeal deformity, which consisted of 17 percent of the patients. Post-operatively, patients were allowed full weightbearing in post-op surgical shoe for a minimum of six weeks. Furthermore, clinical and functional scoring systems such as the American Orthopedic Foot & Ankle Society (AOFAS), Visual Analogue Scale (VAS), and the Foot and Ankle Outcome Score (FAOS) were assessed.

Results: The authors describe statistically significant improvements in AOFAS and VAS scores post-operatively, when compared to pre-operative scores. All subscores of the AOFAS increased or remained unchanged, except for the first metatarsophalangeal joint range of motion score, which decreased in the intermediate and long term evaluations. There was an inverse correlation between AOFAS scores and HVA post-operatively. The authors also reported a positive correlation between post-operative HVA and VAS scores; higher post-operative HVA correlated with higher VAS scores. All radiographic parameters also had significant improvement, long term; although, reoccurrence of radiographic angles like HVA was seen in 28 (30 percent) of the 93 patients, at final follow-up. Complications reported include; (1) one revision surgery at 118 months due to reoccurrence of the hallux valgus deformity, (2) development of transfer metatarsalgia in three patients, (3) hardware removal in 13 patients secondary to pain, and (4) post-op hallux varus deformity in two patients.

Conclusion: Reoccurrence of HVA > 20 degree occurred in one-third of all patients who underwent Scarf osteotomies with minimally invasive lateral release. This happened almost within the first 1.5-2.8 years, and correlated with higher pain levels encountered post-operatively. Some risks factors, the authors recognized, which may have led to increased incidence of reoccurrence include; higher pre-operative HVA, DMMA and failure to restore sesamoid position, post-operatively. Although the minimally invasive lateral release might be a viable option, this approach may not allow for sufficient visualization of all lateral soft tissue structures and adequate anatomic or sequential release. It is my opinion that with proper patient selection, adequate reduction of angles, and proper visualization of lateral soft tissue structures reduction recurrence could be obtained. Some limitations mentioned by the authors include the study’s retrospective nature and lack of a control group for comparison.