[Degenerative cartilage changes in metatarsosesamoidal joint and Scarf procedure results for hallux valgus: a prospective study of 100 cases].
OBJECTIVE
Sesamoid bones of the hallux play a major role in the biomechanics of the metatarsophalangeal complex. Due to the deformations resulting from hallux valgus, the sesamoid system is exposed to abnormal stress forces. Mapping the degenerative cartilage shows the significant prevalence of these lesions and their relation with the anatomic deformation. The purpose of this work was to determine the impact of these metatarsosesamoidal joint changes on the results of Scarf procedure for hallux valgus.


METHODS
This series included 89 patients (100 feet) who underwent Scarf osteotomy with complementary phalangeal osteotomy. We distinguished two groups in this cohort: 78 cases of surgery not involving the lateral metatarsals (group A), and 22 cases with associated lateral metatarsal osteotomy (group B). Mean follow-up was 2.3 years; minimal follow-up 16 months. The study protocol was prospective, with preoperative and last follow-up radiological and clinical assessment by an independent operator. Joint lesions noted intraoperatively by one senior operator were noted. The clinical work-up included the AOFAS score. A 15 degrees anteroposterior weight-bearing view was used to determine the degree of sesamoid dislocation and measure the following angles: first metatarsophalangeal angle (M1P1), first intermetatarsal space (M1M2), proximal articular set angle (PASA). Eleven zones were described to map the joint surfaces. The statistical analysis was used to search for links between joint lesions and the radiographic and clinical findings.


RESULTS
The joint cartilage analysis revealed lesions involving the sesamoid bones in 72 cases, with a preferential involvement of the medial sesamoid bone (67%). The plantar joint surface of the first metatarsal presented lesions in the medial gutter in 72 cases, and in the lateral gutter in 68. Complete absence of the intersesamoid crest was noted in 38%. The metatarsophalangeal compartment presented degenerative lesions in 15 cases. The preoperative assessment noted a positive significant correlation between the AOFAS overall score and the absence of lesions involving the lateral sesamoid bone (p=0.015), between the AOFAS pain score and the absence of lesions involving the lateral sesamoid bone (p=0.022), between the AOFAS pain score and the complete absence of the intersesamoid crest (p=0.001), between the AOFAS deviation score and the absence of lesion involving the lateral gutter (p=0.001), between the M1P1 angle and the absence of an intersesamoid crest (p=0.001). At last follow-up, there was a positive significant correlation between the absence of lesions involving the medial sesamoid bone and a better overall AOFAS score (p=0.014), between absence of a lateral sesamoid lesion and better postoperative sentering of the sesamoids (p=0.014), between the absence of lesion in the medial gutter and a higher postoperative M1P1 angle (p=0.002), between the absence of lesions involving the lateral gutter and more favorable overall AOFAS score (p=0.005) for function (p=0.022), and deviation (p=0.018), between the absence of intersesamoid crest lesions and better radiographic sesamoid recentering (p=0.020). Distinct analysis of groups A and B did not demonstrate a significant difference compared with the overall cohort. Comparison of the two groups only demonstrated three significant differences involving radioclinical parameters.


CONCLUSIONS
Hallux valgus is associated with very frequent metatarsosesamoid lesions. The distribution of these lesions is a function of the anatomic and biomechanical features of the metatarsosesamoid joint surfaces. Lesions to the lateral compartment would be a poor prognostic factor for Scarf procedure.
Largey
A
A
Service orthopédie-3, CHU Lapeyronie, 191, avenue Gaston-Giraud, 34295 Montpellier cedex 5, France. arnaudlargey@hotmail.com
Canovas
F
F
Roussanne
Y
Y
Hebrard
W
W
Bonnel
F
F
D002357:Cartilage Diseases / Q000150:complications* / Q000601:surgery*; D002358:Cartilage, Articular; D005260:Female; D033023:Foot Joints; D006215:Hallux Valgus / Q000150:complications* / Q000601:surgery*; D006801:Humans; D008297:Male; D008682:Metatarsal Bones; D008875:Middle Aged; D011446:Prospective Studies; D012716:Sesamoid Bones