Advertisement

Irreducible dislocation of the fourth metatarsophalangeal joint—a case report

      Traumatic dislocation of the metatarsophalangeal joint of an isolated lesser toe is an uncommon injury. We report a patient who presented 1 day after a dorsiflexion injury of the right foot. Physical examination showed a shortened and angulated right fourth toe resulting in scissoring of his digits. X-rays of the right foot confirmed complete dislocation of the fourth metatarsophalangeal joint. After failing 4 attempts at closed reduction, an orthopedic consult was made, and he underwent surgery. Six months after the operation, he developed avascular necrosis of the fourth metatarsal head. Reduction of the metatarsophalangeal of an isolated lesser toe is difficult due to the anatomical constraints imposed by the surrounding soft tissue. Failure at reduction after a single attempt by an experienced emergency physician should prompt the need for an orthopedic consult in view of likely surgery required. Avascular necrosis of the metatarsal head can also occur as a late complication after such injury.
      Traumatic dislocation of the metatarsophalangeal joint (MTPJ) of an isolated lesser toe is an uncommon injury [
      • Rao J.P.
      • Banzon M.T.
      Irreducible dislocation of the metatarsophalangeal joints of the foot.
      ,
      • Nakano Y.
      • et al.
      Irreducible dorsal MTP joint dislocation in the second and third toes.
      ,
      • Boussouga M.
      Irreducible dorsal metatarsophalangeal joint dislocation of the fifth toe: a case report.
      ]. To our knowledge, there are no large studies available to document the incidence of such injuries. The consequence of prolonged dislocation has been studied on larger joints showing an increased risk of avascular necrosis [
      • Sahin V.
      • Karakaş E.S.
      • Aksu S.
      • Atlihan D.
      • Turk C.Y.
      • Halici M.
      Traumatic dislocation and fracture-dislocation of the hip: a long-term follow-up study.
      ,
      • Goddard N.J.
      Classification of traumatic hip dislocation.
      ,
      • Phillips A.M.
      • Konchwalla A.
      The pathologic features and mechanism of traumatic dislocation of the hip.
      ]. We describe a patient with delayed presentation of an isolated fourth MTPJ dislocation who failed close reduction in the emergency department and had to be treated with surgery.
      A 61-year-old gentleman presented 1 day after a dorsiflexion injury of the right foot after jumping off a lorry about 1 m in height. He had pain and swelling over his right forefoot and was unable to bear weight. Physical examination showed a shortened and angulated right fourth toe resulting in scissoring of his digits. X-rays of the right foot confirmed loss of joint congruency and complete dislocation of the fourth MTPJ (Fig. 1).
      Figure thumbnail gr1
      Fig. 1Anteroposterior and oblique x-rays showing dislocation of the fourth MTPJ.
      Despite adequate analgesia and sedation, a total of 4 attempts at close reduction in the emergency department were unsuccessful. Subsequently, an orthopedic consult was sought, and the patient underwent open reduction of the dislocation with Kirschner wire fixation under general anesthesia.
      Surgery was performed via a dorsal approach. The metatarsal head was found to have dislocated in the plantar direction, exposing the articular surface of the proximal phalanx. The interposed plantar capsule was seen to obstruct reduction and had to be excised. However, attempts to bring the metatarsal head dorsally remained unsuccessful. The deep transverse metatarsal ligament was then divided, followed by release of the fibrocartilaginous plantar plate. In view of joint instability after multiple soft tissue releases, a 1.6-mm Kirschner wire was passed through the joint for splintage.
      Postoperatively, the patient was started on non–weight-bearing ambulation. His wound healed 2 weeks after the surgery, and the Kirschner wire was removed at 2 months. The patient was last reviewed 6 months after his surgery. He complained of mild, persistent right foot pain. X-rays showed osteolysis of the fourth metatarsal head (Fig. 2). Because he remained ambulant and preferred conservative management for his injuries, no further surgery was scheduled.
      Figure thumbnail gr2
      Fig. 2Anteroposterior, oblique, and true lateral x-rays showing avascular necrosis of the fourth metatarsal head at 6 months.
      The MTPJ is supported by articular capsule and its associated collateral, dorsal, and plantar ligaments. In addition, the fibrocartilaginous plantar plate located at the metatarsal head is capable of enduring compressive and tensile forces, [
      • Gregg J.
      • et al.
      Histologic anatomy of the lesser metatarsophalangeal joint plantar plate.
      ,
      • Johnston III, R.B.
      • Smith J.
      • Daniels T.
      The plantar plate of the lesser toes: an anatomical study in human cadavers.
      ], giving the joint added stability. It has several reinforcements—medial and lateral collateral ligaments, intermetatarsal ligaments, interosseous tendons, lumbricals, extensor digitorum longus, and brevis as well as flexor tendons [
      • Yu G.V.
      • et al.
      Predislocation syndrome. Progressive subluxation/dislocation of the lesser metatarsophalangeal joint.
      ].
      Dislocation at the MTPJ occurs with forced extension of the foot, which is consistent with the injury sustained by our patient [
      • Rao J.P.
      • Banzon M.T.
      Irreducible dislocation of the metatarsophalangeal joints of the foot.
      ,
      • Gentless J.
      • et al.
      First and second metatarsophalangeal joint dislocation. A case report.
      ,
      • Murphy J.L.
      Isolated dorsal dislocation of the second metatarsophalangeal joint.
      ]. Upon landing, the excessive dorsiflexion force on the forefoot caused the metatarsal head to be pushed in a plantar direction. This then ruptures the plantar plate [
      • Yu G.V.
      • et al.
      Predislocation syndrome. Progressive subluxation/dislocation of the lesser metatarsophalangeal joint.
      ] and dislocates the joint. The metatarsal head is then trapped between the plantar plate on the volar surface, deep transverse metatarsal ligament on the dorsal surface, the flexor tendons on the lateral aspect, and the lumbrical tendons on the medial aspect. In fact, similar findings have been described in the literature. Rao and Banzon [
      • Rao J.P.
      • Banzon M.T.
      Irreducible dislocation of the metatarsophalangeal joints of the foot.
      ] noted interposition of the plantar capsule and deep transverse metatarsal ligament, whereas Hynes et al [
      • Hynes D.
      • D'Souza L.G.
      • Stephens M.
      Irreducible dislocation of the fifth metatarsophalangeal joint: a case report.
      ] observed incarceration of the metatarsal head under the flexor digitorium longus. In our patient, reduction was only possible with the division of the plantar plate, deep transverse metatarsal ligament, dorsal capsule, and excision of the capsular tissue.
      In the emergency department, the findings of a shortened and angulated toe with scissoring of the digits may be subtle if the swelling is substantial. Under such circumstances, a confirmatory x-ray would be helpful. This should include true orthogonal views 90° to each other to avoid missing any dislocation in the plane of the x-ray projection. Upon confirmation of the diagnosis, closed manipulation can then be attempted by applying traction to dis-impact the bones, followed by manipulation to realign the joint. However, owing to the inherent difficulties with this kind of dislocation, multiple attempts are not advisable. An orthopedic referral should be made after a single failed attempt by an experienced emergency physician. [
      • Rao J.P.
      • Banzon M.T.
      Irreducible dislocation of the metatarsophalangeal joints of the foot.
      ,
      • Nakano Y.
      • et al.
      Irreducible dorsal MTP joint dislocation in the second and third toes.
      ,
      • Boussouga M.
      Irreducible dorsal metatarsophalangeal joint dislocation of the fifth toe: a case report.
      ,
      • Hynes D.
      • D'Souza L.G.
      • Stephens M.
      Irreducible dislocation of the fifth metatarsophalangeal joint: a case report.
      ].
      Prolonged dislocation leading to avascular necrosis has been described in the hip joint [
      • Boussouga M.
      Irreducible dorsal metatarsophalangeal joint dislocation of the fifth toe: a case report.
      ,
      • Sahin V.
      • Karakaş E.S.
      • Aksu S.
      • Atlihan D.
      • Turk C.Y.
      • Halici M.
      Traumatic dislocation and fracture-dislocation of the hip: a long-term follow-up study.
      ], with the rate of avascular necrosis varying from 5% if the hip is reduced in less than 6 hours after injury to 50% if the hip is reduced more than 6 hours after injury [
      • Goddard N.J.
      Classification of traumatic hip dislocation.
      ]. Although the cause of avascular necrosis in our patient could be contributed by delayed reduction of the joint, it could also be secondary to loss of blood supply to the joint after extensive soft tissue dissection. Nevertheless, this case highlights some of the challenges in the management of such injuries.

      Acknowledgment

      The authors would like to thank Dr. Sim Tiong Beng for his ideas in the course of this project.

      References

        • Rao J.P.
        • Banzon M.T.
        Irreducible dislocation of the metatarsophalangeal joints of the foot.
        Clin Orthop Relat Res. 1979; 145: 224-226
        • Nakano Y.
        • et al.
        Irreducible dorsal MTP joint dislocation in the second and third toes.
        Injury. 2003; 34: 870-873
        • Boussouga M.
        Irreducible dorsal metatarsophalangeal joint dislocation of the fifth toe: a case report.
        J Foot Ankle Surg. 2010; 49: 298e17-298e20
        • Sahin V.
        • Karakaş E.S.
        • Aksu S.
        • Atlihan D.
        • Turk C.Y.
        • Halici M.
        Traumatic dislocation and fracture-dislocation of the hip: a long-term follow-up study.
        J Trauma. 2003; 54: 520-529
        • Goddard N.J.
        Classification of traumatic hip dislocation.
        Clin Orthop Relat Res. 2000; 377: 11-14
        • Phillips A.M.
        • Konchwalla A.
        The pathologic features and mechanism of traumatic dislocation of the hip.
        Clin Orthop Relat Res. 2000; 377: 7-10
        • Gregg J.
        • et al.
        Histologic anatomy of the lesser metatarsophalangeal joint plantar plate.
        Surg Radiol Anat. 2007; 29: 141-147
        • Johnston III, R.B.
        • Smith J.
        • Daniels T.
        The plantar plate of the lesser toes: an anatomical study in human cadavers.
        Foot Ankle Int. 1994; 15: 276-282
        • Yu G.V.
        • et al.
        Predislocation syndrome. Progressive subluxation/dislocation of the lesser metatarsophalangeal joint.
        J Am Podiatr Med Assoc. 2002; 92: 182-199
        • Gentless J.
        • et al.
        First and second metatarsophalangeal joint dislocation. A case report.
        J Am Podiatr Med Assoc. 1992; 82: 630-632
        • Murphy J.L.
        Isolated dorsal dislocation of the second metatarsophalangeal joint.
        Foot Ankle. 1980; 1: 30-32
        • Hynes D.
        • D'Souza L.G.
        • Stephens M.
        Irreducible dislocation of the fifth metatarsophalangeal joint: a case report.
        Foot Ankle Int. 1994; 15: 625-626