It is important to note that the difference between a good and an excellent Mayo score was the fact that the patient did not have symmetric grip strength. Coincidentally, the patient did injure his nondominant hand and it may very well be that his grip strength was asymmetric before injury. As with most people, the patient states that he did not have symmetric grip strength before injury.
This case is unique as it is the first we have encountered to describe a trans-scaphoid trans-lunotriquetral perilunate dislocation in a patient with a lunotriquetral coalition. Devilliers Minnaar9 described lunotriquetral coalitions and classified them into 4 types: type I, incomplete fusion representing a pseudoarthrosis; type II, fusion with notch of carrying depth; type III, complete fusion of lunate and triquetrum; and type IV, with complete fusion and other carpal anomalies. The patient described was determined to have a type III coalition. The complete fusion restricts motion between the anatomic structures of the hand thereby avoiding degenerative arthritis or impingements leading to pain.10
Trans-scaphoid perilunate fracture dislocations are high-energy injuries produced by wrist hyperextension where the scaphoid is fractured and there is dislocation of the capitate from the lunate.11,12 Complete coalitions have a propensity to fracture with trauma due to poor transmission of forces.4,6,7,10
Surgical intervention is the mainstay of treatment for perilunate fracture dislocations. Initial management can be either early surgical intervention or delayed surgical treatment following closed reduction dependent on the amount of soft-tissue swelling and time to presentation.12,13 If excessive swelling is present with early presentation following injury, as in this case, closed reduction followed by delayed surgical intervention is preferred.
The main debate remains as to whether a trans-scaphoid perilunate dislocation can be managed closed or whether the ligamentous injury must be directly repaired. Many surgeons have emphasized the need for repair of the interosseous ligament to stabilize the carpal architecture, whereas some investigators suggest that maintenance of anatomic position is sufficient to reestablish stability without ligamentous repair.14–18 Various surgical techniques have been described with a majority showing acceptable outcomes with open reduction and internal fixation.12,19–24 Although most reports describe open approaches, these involve soft-tissue dissection that have been shown to increase the risk of disrupting the blood supply to the scaphoid.25 Closed reduction with percutaneous fixation has been shown to have excellent functional outcomes in patients with trans-scaphoid perilunate injuries.13,21,26 One of the main objectives to open approaches is to repair the lunotriquetral ligament. However, due to the absence of a lunotriquetral joint in this patient, rigid fixation of the coalition was the treatment objective. Without fixation, disruption of a lunotriquetral coalition has been reported to lead to painful pseudoarthrosis.27 Achieving proximal stability through the use of percutaneous screw fixation of the lunotriquetral coalition and the scaphoid allowed for healing and bony union of the fractures (Fig. 3). Using this minimally invasive approach, we achieved good outcomes for this patient as determined by the Mayo functional score of 80 (Table 1).
Trans-scaphoid trans-lunotriquetral perilunate dislocations with a lunotriquetral coalition are exceedingly rare. Initial management requires reduction of the dislocation and fractures followed by surgical fixation. Percutaneous fixation can be considered for patients in whom the fracture is closed, and reduction of the dislocation and fractures is achieved through closed manipulation. Percutaneous fixation allows for proximal stability leading to carpal healing and complete bony union. Finally, percutaneous fixation of trans-scaphoid trans-lunotriquetral perilunate dislocation may lead to a good to an excellent functional outcome.
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