The intra-articularly located ligament variation of the first metatarsophalangeal joint
Article Outline
Abstract
An intra-articularly located ligament in the first metatarsophalangeal joint of the left foot has been detected in a patient. The intra-articular ligament was dorsomedially attached to the head of the first metatarsal and to the inferior part of the articular face of the base of the proximal phalanx of the big toe. In a literature search we could not find any report of a ligament located intra-articularly in this particular joint. Such a variation may have a role in the etiology of hallux valgus.
Keywords: The first metatarsophalangeal joint, Extra ligament, Variation, Hallux valgus
1. Introduction
Metatarsophalangeal joints (MPJ) are classified within the spheroid joints when considering joint shape and within the elipsoid joints when considering joint movement [1]. Articular capsule, plantar ligaments, deep and transverse metatarsal ligaments and collateral ligaments constitute the ligaments of these joints [2]. Collateral ligaments are round and strong ligaments on each side of these joints [1]. They run from the dorsal aspects of the lateral faces of the distal tips of the metatarsal bones obliquely downwards and forwards and insert into the lateral aspect of the base of the corresponding proximal phalanx [1]. The joint capsule is inseparable from the collateral ligaments and the plantar ligament in each of these joints [2]. The first MPJ is one of the most significant structures in the forefoot. The first MTP is composed of four bones, nine ligaments, and three muscular attachments. The first MPJ formed by the convex metatarsal head, the concave proximal phalanx, and the superior surfaces of the medial and lateral sesamoids. Six of the ligaments exist in pairs: two collaterals, two sesamoids, and two plantar. In addition to the six, there are intersesamoid, and deep transverse ligament. The plantar intrinsic muscles that insert into the first MPJ capsule are the adductor hallucis, abductor hallucis, and flexor hallucis brevis [3].
Hallux valgus is characterised by lateral deviation of the first toe and medial deviation of the first metatarsal bone. If the hallux valgus angle (HVA) is greater than 15° and the intermetatarsal angle is greater than 9° on standing, antero-posterior radiographs then, hallux valgus may be diagnosed. Usually it is seen in people who wear Western shoes. Additionally neuromuscular diseases, systemic diseases such as rheumatoid arthritis, a genetic tendency and metatarsus primus varus are suggested among the intrinsic factors that play role in the etiology of hallux valgus [4], [5], [6], [7].
2. Case report
In this study, we took into consideration the operative results of the 23 feet of 18 (3 female and 15 male) patients with hallux valgus between 2003 and 2006. The average age in the group was 40 (16–62 years). Before the operation standing antero-posterior, and lateral radiographs were taken for all patients at the standing position. At the radiographic examination these measures were evaluated: hallux valgus angle, intermetatarsal angle, distal metatarsal joint angle, medial sesamoid position, metatarsophalangeal joint arthrosis, metatarsophalangeal joint subluxation. In one of these 23 feet an intra-articular ligament was detected as surgery. This was the left foot of a 52-year-old male patient. During the operation a ligament within the cavity of the first metatarsophalangeal joint was found distinct from the joint capsule and which originated from the dorsomedial aspect of the head of the first metatarsal bone and passed obliquely to insert to the inferior part of the articular facet of the base of the proximal phalanx (Fig. 1, Fig. 2).
Fig. 1.
The view of the dissected capsule of the first MTP joint.
Fig. 2.
The view of the intra-articular ligament located within the first MTP joint and the neighboring structures.
3. Discussion
Unfortunately, there are few studies published about the anatomy of this joint. In daily surgical practice related to hallux valgus, it is unusual to observe the soft tissues inside the first metatarsophalangeal joint. The structure described by the authors may be the medial collateral MTP ligament which is elongated due to the position of the hallux or it may be meniscoid tissue. In a search of the literature, Dereymaeker and Mulier mentioned that in 102 cadavers the first MPJ meniscus was present in 19% of cadavers. They also detected that the presence of the meniscus was higher and was present in 33% of the cadavers having hallux valgus deformity. [8]. We have not encountered any mention of an intra-articular ligament of the first metatarsophalangeal joint in the literature. The direction of the ligament in our case resembled the direction of the medial collateral ligament which was not detected additionaly in our case. Whether such a variation can play a role in the etiology of hallux valgus can be proved only if more reports of such coexistence occur in future.
References
- . Anatomy. vol. 1. Ankara: Güneş Company (Publisher); 1997;p. 138–9
- . Pelvic girdle and lower limb. Gray's anatomy. 39th ed.. London, UK: Churchill Livingstone Medical Division of Longman; 2005;p. 1529–30
- . Pathological anatomy of hallux abductio valgus. Clin Podiatr Med Surg. 1989;6(1):1–15
- . Hallux valgus. J Bone Joint Surg (Am). 1996;78:932–966
- . Hallux valgus. In: Adelaar RS editors. Disorders of the great toe. 1st ed.. Illinois: American Academy of Orthopaedic Surgeons; 1997;p. 43–62[monograph series]
- . Hallux valgus-etiology, anatomy, treatment and surgical considerations. Clin Orthop. 1981;157:31–41
- . Osteotomy and fixation for hallux valgus. Clin Orthop. 1981;157:42–46
- Dereymaeker G, Mulier T. The first metatarsophalangeal joint meniscus: an anatomical and clinical study. Naamsestraat, Leuven, Belgium: Foot and Ankle Clinic, Heilig hart ziekeenhuis.
PII: S1268-7731(07)00091-4
doi:10.1016/j.fas.2007.10.001
© 2007 European Foot and Ankle Society. Published by Elsevier Inc. All rights reserved.
