Volar dislocation of four carpometacarpal joint: A rarest injury

This article reports a case of young male grieved with fracture dislocation of the four carpometacarpal (CMC) joints dislocation due to motor vehicle collision. Volar- radial deviation of the second and third CMC joints and volar- ulnar deviation of fourth and fifth CMC joints were observed. Patient was treated with closed reduction and fixed with 0.045 K wires. First wire was placed in third metacarpal and capitate and second wire was placed from fifth metacarpal base to the proximal row of carpals. Despite all effort complete reduction at fourth and fifth CMC joint was not achieved. Follow up radiographs at one month showed satisfactory reduction and patient is performing well till the last follow up. Intensive postoperative physiotherapy is vital to achieving a satisfactory outcome.


Introduction
Metacarpal fractures and dislocation account for 1% of all hand injuries 1 . Men aged 10-29 have highest incidence of metacarpal injuries. Carpometacarpal (CMC) fracture dislocations are developed due to a direct high-energy blow on to the hand. Any type of displacement of the metacarpals is determined by the direction of the force applied to the hand at the time of injury 2 . The carpometacarpal joints of the hand are gliding type of joints. The distal row of the carpal bones articulates with the bases of the metacarpals and with each other. All ligaments like Intermetacarpal and carpometacarpal, as well as ligaments of the wrist flexors and extensors those are inserted to the bases of the second, third, and fifth metacarpals, reinforce the joints 1 .
Although volar type of CMC dislocation are very rare type of injury, but it was first described by McWhorter in 1918 3 . All of the ligamentous and tendonous structures are disrupted in the volar-radial displacement which may cause marked displacement of the metacarpal base. The pisometacarpal ligament remains intact in the volar-ulnar type of displacement, which preventing excessive displacement of the fifth metacarpal base. There are chances of concomitant soft tissue injuries like tendon laceration and neurovascular injury.
In the literature many cases were reported of one or two volar CMC joints dislocations which were treated by closed reduction and casting 4,5 , while open reduction and internal fixation is usually required in unstable type of injury. The patients usually complain of pain as well as grip weakness due to failure to diagnose these injuries or inability to maintain an anatomic reduction 6,7 . The purpose of this report is to present a case of all four CMC joints dislocations. It is a very rare injury. After extensive search on pubmed we did not find any case report of volar displacement of all four CMC joints injury.

Case report
A 22 year old, young male met with a motor vehicle collision and fell onto his forced palmer flexed right hand. He noticed immediate pain and deformity of his hand and presented himself to author. On physical examination marked widening in between all fingers as well as swelling with significant bruising over the dorsum of the wrist ( fig 1) and hand was observed.

Abstract
This article reports a case of young male grieved with fracture dislocation of the four carpometacarpal (CMC) joints dislocation due to motor vehicle collision. Volar-radial deviation of the second and third CMC joints and volar-ulnar deviation of fourth and fifth CMC joints were observed. Patient was treated with closed reduction and fixed with 0.045 K wires. First wire was placed in third metacarpal and capitate and second wire was placed from fifth metacarpal base to the proximal row of carpals. Despite all effort complete reduction at fourth and fifth CMC joint was not achieved. Follow up radiographs at one month showed satisfactory reduction and patient is performing well till the last follow up. Intensive postoperative physiotherapy is vital to achieving a satisfactory outcome. Keywords: carpometacarpal joint, volar radial, volar ulnar, K wires IJBR (2014) 05 (10) www.ssjournals.com Empty space over dorsal aspect of hand and bony prominences felt on thenar and hypothenar region (fig 2). Sensation over the median and ulnar nerve distributed area was intact. All thenar, hypothenar and inteossei muscles were working properly. Capillary refilling was within normal limits. Anteroposterior radiograph showed widening of all intermetacarpal distance and normal relationship of distal row with base of all metacarpals found disturbed, second and third CMC joints was radially deviated and ulnar deviation of fourth and fifth CMC joints were observed (fig 3). On oblique view all four metacarpal was volarly dislocated. True lateral view was not taken due to severe pain as patient was not co-operating. CT scan was not done due to financial concerns.

Fig 3: Preoperative oblique and anteroposteriorradiograph showed widening of all intermetacarpal distance, disruption of relationship of distal row with base of metacarpals, volar-radial deviation of the second and third CMC joints and volar-ulnar deviation of fourth and fifth CMC joints
Patient was taken to Operation Theater and closed reduction was performed under general anesthesia. Reduction was not stable on releasing traction, the metacarpals dislocated towards volar side hence fixed with 0.045 K wires. First wire was placed in third metacarpal and capitate and second wire was placed from fifth metacarpal base to the proximal row of carpals (fig 4).

Fig 4: Postoperative radiograph showed fixation with K wires, one wire placed in third metacarpal and capitate and another one placed from fifth metacarpal base to the proximal row of carpals
Despite all effort we could not achieved complete reduction at fourth and fifth CMC joint. Patient and his relatives did not agree for open reduction, hence no further procedure was undertaken and a volar POP slab was given for one month. After one month POP slab and K wire were removed and radiograph of hand was taken (Fig 5). IJBR (2014) 05 (10) www.ssjournals.com

Ethical Considerations
Informed consent was taken from the patients prior to operation and for the inclusion to the study.

Discussion
Volar dislocations of all four CMC joints are very rare injury. Only two reports of isolated volar index finger CMC dislocations 8,9 and two reports of volar CMC dislocations of the index and long fingers 2,10 are mentioned in literature. Volar CMC dislocations of the four ulnar metacarpals are reported by three authors 4,11,12 . In our case report not only volar dislocation of all four CMC joints but two CMC joints were dislocated towards radial side and two towards ulnar side which is a very rare occurence.
Either dorsal or volar CMC dislocation may create severe consequences if they were not identified and treated adequately. Neu rovascular evaluation is compulsory due to chances of injury to deep motor branch of the ulnar nerve in both dorsal 13,14 and volar CMC dislocations 15,16 and the median nerve is also affected by volar CMC dislocations 2 . But in present case report no neurovascular compromised had detected. Though many authors described open reduction of this fracture dislocation as the primary treatment but in present case we performed closed reduction and K wire fixation and follow up radiograph showed satisfactory reduction and patient is performing well till the last follow up. Intensive postoperative physiotherapy is vital to achieving a satisfactory outcome.