Influencia de la magnitud del desplazamiento lateral de la cabeza metatarsal tras la osteotomía en chevron para hallux valgus sobre el resultado reportado por el paciente

Resumen

Influence of the amount of metatarsal head lateral displacement after chevron osteotomy for hallux valgus on patient-reported outcome Background: The hallux valgus (HV) is the most common forefoot pathology in adults. One of the most widely accepted surgical technique for its correction is the chevron osteotomy for realignment of the first metatarsal by lateral displacement of the metatarsal head. However, an analysis of the influence of the amount of head displacement on functional outcome and patient satisfaction has not been performed. Objectives: The primary objective was to analyze the influence of the amount of metatarsal head lateral displacement after distal chevron osteotomy of the first metatarsal on the patient-reported outcomes. The secondary objectives were: (1) to identify the minimum displacement of the metatarsal head necessary to obtain a satisfactory result, and (2) to evaluate if the sesamoid position obtained with surgery changed over time and if this had influence on the patient-reported outcome. Material and Methods: Prospective, comparative, cohort study of 97 patients. The clinical assessment was performed by the Self-reported Foot and Ankle score (SEFAS) quality of life questionnaire, American Foot and Ankle Society score (AOFAS), Visual Analogue Scale (VAS) for pain, and 5-likert scale for patient’s satisfaction. Radiologically, the lateral displacement of the metatarsal head was quantified by: a) intermetatarsal angle (IMA); and b) lateral linear displacement. Patients were divided into two groups according to whether they presented a postoperative increase greater than or equal to or less than the minimum clinically important difference (MCID) of 9 points on the SEFAS scale. For the secondary objective (1) a ROC analysis was performed, and for (2) the patients were grouped according to the sesamoid position obtained with surgery. Results: There was no significant association between the magnitude of the lateral displacement of the metatarsal head measured by AIM and the postoperative SEFAS score. In the ROC curve, a significant cut-off point in the AIM was not found for the discrimination of the patients with a final SEFAS score equal or greater to DMCI (area under the curve, AUC= 0.46; p= 0.611). Likewise, for lateral linear displacement (AUC 0.47, p= 0.730). In multivariate analysis, significant predictors of successful SEFAS were only the final VAS-pain and correct position of the sesamoids. The 66 patients with a normal sesamoid position obtained in the surgery had no sesamoid position changes at the final follow-up. Contrary, 8 (25,8%) patients of the 31 with wrong sesamoid positions had a worsening of their sesamoid positions over time, and worse final SEFAS (p= 0,003), VAS-pain (p= 0,026) and satisfaction (p= 0,010) at the final follow-up. Conclusion: The amount of metatarsal head displacement does not influence patient-reported outcome as measured by the SEFAS score, but it does influence patient's satisfaction with the surgery. An incorrect sesamoid position obtained in surgery can lead to a worsening of said position over time and worse functional outcome. The main factor of successful outcome is not so much the amount of metatarsal head lateral displacement as obtaining a correct coverage of the sesamoids in the surgery.