This study analyses the Reverdin Isham procedure, which is the most popular minimally invasive surgical hallux valgus correction method and the minimally invasive chevron osteotomy, representing the standard technique of open surgery. It is hypothesized that the two techniques would show significant differences in regard to radiological outcome (Hypothesis 1), clinical outcome (Hypothesis 2) and development of radiological recurrence (Hypothesis 3).

Multiple different surgical techniques have been established for hallux valgus surgery so far, each technique with its unique advantages and limitations. The distal chevron method is widely accepted as a surgical method for correcting mild to moderate hallux valgus deformities. Numerous publications presenting the radiological outcome of this surgical technique and the clinical outcome by means of well established score systems have been published and make this technique, today's benchmark in hallux surgery.

Due to scarring and decreased range of motion of the greater toe joint after open surgery and increasing patients' demands several minimally invasive techniques have been brought to public in the last few years. These techniques claim minor soft tissue damage and reduced surgical time. The efficiency and stability of correction, as well as the clinical outcome of these techniques have been discussed controversially. However, most studies present data from minimally invasive surgery without specific differentiation of the type of surgery and in regard to the clinical and radiological outcome.

Recently a prospective randomized study comparing the open versus the minimally invasive chevron technique has been published presenting data with comparable clinical and radiological outcome.

Given the above-mentioned lack of evidence it was the aim of the study to compare the results of two different minimally invasive techniques. The investigators analyzed the Reverdin Isham procedure, which is known as the technique, that made minimally invasive hallux surgery popular and the minimally invasive chevron osteotomy. It was hypothesized that the two techniques would show significant differences in regard to radiological outcome (Hypothesis 1), clinical outcome (Hypothesis 2) and development of radiological recurrence (Hypothesis 3).

Inclusion Criteria:

• patients after minimally invasive distal Chevron osteotomy for hallux valgus deformity with a Minimum follow up of 24 months
• patients with informed written consent for being analyzed
• patients, of whom radiographs are available from preoperative throughout the follow-up time of 24 months

Exclusion Criteria:

• patients under 18 years of age
• pregnant patients, or women below the age of 50 ys, of whom the pregnancy status is not clear
• patients with mental illness or patients, who cannot follow the required postoperative Treatment or controls
• patients, who refuse to participate
• patients, who are assigned to other clinical studies

A rseries of a cohort of hallux patients treated with the minimally invasive Chevron ostotomy with a Minimum follow-up of 24 months is analyzed retrospectively in regard to the clinical (different clinical scores) and radiological Outcome (radiographic Analysis of defined angles).