perilunate fracture dislocations represent uncommon and unusual injuries that are often missed at initial presentation in up to 25% of cases . a neglected injury of this type can result in progressive carpal instability with ensuing post - traumatic arthritis , leading to pain and dysfunction . prompt open reduction , carpal stabilisation and ligamentous repair is required to reduce the risk of complications . we report a case of an established scaphoid non - union in an operatively managed perilunate fracture dislocation that spontaneously united almost 2  years after the initial injury , just before a planned revision scaphoid fixation with bone grafting . to our knowledge , and following an extensive literature search of the pubmed and medline databases , such a case has not been reported on before . a 19-year - old , right - hand - dominant , smoker attended the emergency department with left wrist pain and swelling following a fall down a staircase . 1 ) were interpreted as showing a radial styloid fracture , and he was managed in a below - elbow back slab and referred to the fracture clinic.fig . 1wrist pa x - ray at presentation showing a displaced scaphoid fracture with disruption of gilula s arcs ( 1 and 2 ) wrist pa x - ray at presentation showing a displaced scaphoid fracture with disruption of gilula s arcs ( 1 and 2 ) at review in the fracture clinic the next day , his radiographs were correctly interpreted with an additional true lateral wrist view ( fig . he had symptoms of median nerve compression at the wrist . computed tomography ( ct ) scan was not performed , and he underwent immediate surgical management . this involved a volar incision to decompress the carpal tunnel , reduce the lunate and repair the rent in the volar capsule . through a dorsal approach , k - wire stabilisation of the carpal bones was performed , followed by a triquetro - lunate ligament repair using a mitek suture anchor ( fig . his median nerve symptoms resolved post - operatively , and he was discharged home in a below - elbow cast . the k - wires were removed at 4  weeks and he was placed into a wrist splint.fig . 3wrist pa x - ray taken post - operatively wrist lateral x - ray showing volar perilunate dislocation wrist pa x - ray taken post - operatively unfortunately he failed to attend any further follow - up and was re - referred 12  months later with on - going pain at the base of the thumb . he had scaphoid tenderness on palpation in the  anatomical snuff box but also pain on radial deviation and a reduced range of movement ( flexion 20 , extension 30 ) . radiographically , he had features of a scaphoid non - union ( fig .  4 ) . it was elected to proceed to revision of the scaphoid fixation with cortico - cancellous bone grafting for this non - union . ct scan was not performed as it was felt that the combination of scaphoid tenderness and radiological appearances supported the diagnosis of scaphoid non - union . furthermore , his clinical symptoms warranted surgical intervention at this stage , nearly 13  months post injury.fig . 4wrist pa x - ray at 12  months suggesting non - union of scaphoid fracture wrist pa x - ray at 12  months suggesting non - union of scaphoid fracture on the day of his revision operation , a repeat x - ray ( fig . 5 ) was performed as he was no longer tender over the scaphoid . this suggested union of the scaphoid fracture ( 20  months post injury ) . he did however complain of pain on radial deviation of the wrist , attributed to radial styloid impingement on the scaphoid . a radial styloidectomy was performed to address the impingement , and at his last follow - up ( 6  weeks post - operative ) his symptoms were settling and his wrist mobility was improved , though with some on - going stiffness . 5wrist pa x - ray at 20  months suggesting scaphoid fracture union wrist pa x - ray at 20  months suggesting scaphoid fracture union stability of the carpal bones is dependent on the perilunar ligaments and the scaphoid bone , which acts as a bony bridge between the proximal and distal carpal rows . lesser arc injuries are purely ligamentous and result in perilunar injury , with lunar dislocation being the last stage . transosseous variants are classified as greater arc injuries and represent two - thirds of perilunar dislocations . they result in perilunar injury with fractures of the scaphoid , capitate , radial / ulnar styloid or triquetrum , or combinations thereof . the trans - scaphoid perilunate variant is reported to represent 61% of all perilunate fracture dislocations . the general mechanism of injury results from hyperextension with ulnar deviation and intercarpal supination , as described by mayfield et al .   in 1980 . they suggested four stages of ligamentous disruption , progressing in a radial to ulnar direction , with volar lunate dislocation ( into the space of poirier ) being the final stage . although prompt surgical intervention can potentially avoid progressive carpal instability , it has been reported that over 50% of operatively managed patients can develop post - traumatic arthritis . closed reduction alone is associated with poor outcome in 27% of cases due to difficulties in attaining and maintaining anatomic reduction . prompt open reduction , carpal stabilisation and ligamentous repair is the treatment of choice to prevent this . theoretically , the risk of scaphoid non - union would be higher in the setting of perilunate fracture dislocation due to increased soft tissue damage at time of injury and increased carpal instability thereafter . in a series of 15 operatively managed trans - scaphoid perilunate fracture dislocations , 13 were fixed with herbert screws . three developed non - union and required further bone grafting . in another series , 25 trans - scaphoid perilunate fracture dislocations were operatively managed and no non - unions developed at a mean of 44.6  months . more recently , forli et  al .   reported retrospectively on a series that included seven trans - scaphoid perilunate fracture dislocations managed operatively with a minimum 10  years follow - up . three out of seven had excellent or good mayo wrist score , and four out of seven had radiographical evidence of degenerative changes at follow - up . the authors re - enforce that poor reduction in these injuries leads to worse degenerative changes , however this did not always correlate with wrist function . there have been no reports of spontaneous unions of scaphoid fractures in established non - union following operative fixation in the setting of perilunate fracture dislocation . we are aware of three case reports of established isolated scaphoid non - unions that have spontaneously united , one in a 19-year - old requiring fixation   and the other two in paediatric cases . report on an 11-year - old and manak et  al .   report on a 14-year - old , both with established scaphoid non - unions that proceeded to union at 2  years post injury . the important messages that the presented case highlights are as follows . firstly , perilunate injuries are difficult to diagnose and emergency department doctors should be aware of these injuries . a history of high - energy injury with axial loading of an extended wrist should raise suspicion of a perilunar injury . full clinical evaluation of the wrist and upper limb , including neurological examination , together with appropriate good - quality x - rays is essential . secondly , the importance of pre - operative clinical and radiological re - assessment can not be stressed enough . this is important to prevent possible morbidity associated with unnecessary procedures . in this case , the patient s clinical symptoms were significant enough to warrant surgical intervention . however , this needed to address the radial - sided impingement as the scaphoid had spontaneously united . finally , regular follow - up of these injuries is important for monitoring of rehabilitation and checking for possible complications .
perilunate dislocations and fracture dislocations represent uncommon and unusual injuries that are often missed at initial presentation and diagnosed late in up to 25% of cases . 
 prompt open reduction , carpal stabilisation and ligamentous repair is required to reduce the risk of complications . 
 we report a case of an established scaphoid non - union in an operatively managed perilunate fracture dislocation that spontaneously united almost 2  years after the initial injury , just before a planned revision scaphoid fixation with bone grafting . 
 this case highlights the importance of initial clinical assessment together with appropriate radiographs and follow - up of these injuries post - operatively , especially when complications such as non - union arise .