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Volar dislocations of the finger proximal interphalangeal joint (PIPJ) is a very rare injury. It is often missed in accident and emergency (A&E) and is chronic and irreducible when first seen in the hand clinic. Intrarticular entrapment of the extensor tendon may render close reduction difficult. We report three cases, all sent home from the A&E department, one in the thumb. A good outcome was obtained in these cases with early intervention.
A 20 year old athlete sustained a twisting injury to his left thumb while on a skiing holiday. He had the skiing stick in his left hand and the stick got stuck, his left thumb still being held in the leather loop of the stick sustaining this injury. On examination the interphalangeal joint (IPJ) was swollen and tender. Active flexion was possible but extension was weak and painful. Valgus stress was positive in extension. Radiographs showed mild subluxation of the IPJ. After attempts to close reduce the IPJ failed open reduction was performed. The ulnar collateral ligament was ruptured completely and on valgus stressing the extensor tendon was seen entrapped in S shaped in the IPJ (fig 1). A hook was inserted pulling the tendon and the joint was reduced. The capsule and the collateral ligament was repaired. The thumb was immobilised in 20 degrees of flexion. After two weeks mobilisation was started. This patient made an uneventful recovery.
A 28 year old carpenter was referred two days after injury with pain, swelling, and deformity in his right middle finger. He was struck with the ball while playing volleyball and probably sustained a severe twisting injury. He immediately felt sudden, sharp, shooting pain in his middle finger. He was seen in A&E where no definite bony injury was noted and buddy tapping was applied. The patient returned to A&E the next day unable to cope with the pain and was referred to the hand surgeons. Radiographs showed volar subluxation of the PIPJ. The volar subluxation could be reduced but the finger was unstable and immediately sprung back to subluxed position when left unsupported. On exploration a longitudinal tear was present in the extensor expansion between the central slip and the lateral band with the proximal phalanx protruding through the tear. Reduction was easy once the tear was closed with a continous 4/0 PDS suture (making sure that it was not too tight and that full flexion was still possible). The joint was stable and did not dislocate. At two weeks the finger was mobilised with a good functional result.
A 38 year woman sustained injury to her right index finger. She had attempted removing washed clothes while the washing machine was still slowing down. She felt sudden pain in her right index finger as it got stuck in the hole of the moving drum. She was seen in A&E, buddy tapping was applied. The patient returned to A&E the next day and was referred to the hand surgeons with a suspicion of compartment syndrome of the finger. The right index PIPJ was swollen, tender, and held in slight flexion. End on view of the finger was deformed. Any attempt to straighten the finger passively or actively was met with apprehension. Radiographs (fig 2) showed volar subluxation of PIPJ. On exploration the central extensor tendon although intact was entrapped in the PIPJ. The longitudinal tear in the extensor apparatus was repaired. The follow up was uneventful (fig 3).
The PIPJ is one of the most commonly injured joints in the hand.1 Dislocations of the PIPJ of the hand are comparatively common injuries. Three types of PIPJ dislocations have been described: lateral, dorsal, and volar (rotatory).2 Dorsal and lateral dislocations can usually be reduced in a closed fashion.
Volar (complex rotary) dislocations are rare and uncommon injuries. They are commonly irreducible by closed methods.3,4 These injuries are often missed in A&E and misdiagnosed resulting in delayed treatment and permanent impairment. Early detection, aggressive management, and rehabilitation to avoid significant morbidity is essential.5
The deforming force in these injuries is an axial compression with simultaneous rotational element. Further axial loading and rotational tear leads to opening of the joint as a result of the rotation of the condyles and brings the lateral band of the extensor tendon on the volar side under the head of the proximal phalanx. Once this deforming force is passed off, the finger returns back to a so called normal position but the extensor tendon remains entrapped in the joint. The central slip may remained attached to the middle phalanx or it may become avulsed with or without a fragment of bone.6 This unicondylar proximal phalangeal head notwithholding through an area through the lateral band and the central slip is a major cause preventing successful closed reduction.7 Closed reduction can also be blocked as a result of entrapment of the volar plate,8 avulsed central sleeve,9 lateral band,10 or a displaced articular fracture fragment.11
On clinical examination of volar PIPJ injuries, the joint appears flexed with the distal and the middle phalanges deviated to one side.6 A true lateral radiograph is diagnostic demonstrating an oblique orientation of the middle phalanx and lateral view of the proximal phalanx. Resistance to passive flexion and extension may exist and therefore, careful evaluation of the joint is important to spot the difference between active and passive range of movements, which, in a reduced finger, might indicate loss of central slip function. It is important to determine if the lesion is acute or chronic since the age of the injury will guide the management.
Acute injuries do well if recognised and treated early (fig 4). Late reconstruction of these injuries is technically difficult and often unrewarding. The treatment results are often poor and are particularly related to failure in recognising the rotatory component of the injury and subsequently estimating the degree of instability and the extent of the soft tissue damage.
The complication of these injuries are loss of movements, a chronic laxity, pain, swelling, deformity, and a fixed flexion contracture is common when aggressive attempts to achieve full extension are not undertaken.12
All the reported cases were sent home from the A&E. They returned within a week to the hand clinic with a deformed tender swollen finger, two of them returned, unable to bear the pain. As these are extremely rare injuries a good clinical history and examination is necessary. It may not always be possible to acquire the detailed mechanism of injury especially in a busy A&E department. Clinical examination in an acute painful situation needs a lot of patience and perseverance to locate the exact cause and nature of a closed finger injury. Severe apprehension and lack of cooperation from the patient in an acute setting might also be responsible for these injuries to be missed initially. All these cases required open reduction. Early referral, within the first week, to the hand clinic is essential in a suspected case. If diagnosed late and therefore treated late the final outcome and function is compromised.
We believe that it is extremely important to be aware of this injury. Any passive painful flexion or extension of the finger PIPJ should raise a suspicion. High index of suspicion, awareness and early referral to a hand clinic, subsequent repair and rehabilitation gives a good functional outcome.
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