Perilunate Injury Combined with Lunate Fracture

We present an atypical case of combined comminuted lunate fracture and the scaphoid waist fracture, chip fracture of triquetrum and pisiform. Comminuted scaphoid waist fracture was caused by forced hyperextension of the wrist, similar mechanism to stage I of progressive perilunate instability (PLI), and lunate fracture might be caused by axial compression force, does not appear on the original theory of PLI. We performed closed reduction and screw fixation for the scaphoid fracture and immobilized and mildly distracted the wrist joint with the use of a bridging external fixator to prevent further collapse of comminuted lunate by neutralizing the compression force imposed by the capitate on the lunate. We achieved excellent radiological and clinical outcomes at 29-months of follow-up. We aimed to introduce this rare injury and clinically important points in its treatment with the review of the literature.

Traumatic mechanisms and therapeutic results of the perilunate injuries / Mecanismos traumáticos y resultados terapéuticos en lesiones perisemilunares

OBJECTIVES: In this study, eighteen patients who have had perilunate injury with dislocation or fracture, were evaluated and the patho-mechanics and surgical treatment were studied. SUBJECTS AND METHODS: According to the Green and O 'Brien's classification, type 1 injury occurred in one patient, type 2 in nine, type 4A in five, type 4C in one and type 4D in one. The other one case could not be classified using the Green and O 'Brien's criteria. RESULTS: According to the Evans scoring system, good results were achieved in thirteen patients, fair results, in four, poor results in one and very poor results in none. When the patho-mechanics was esti mated based on the Mayfield's criteria, seventeen patients were classified as stage 3. However, only one case was extremely unusual and should be classified as a subtype of stage 2. CONCLUSION: The results were good in the majority ofpatients who had repair ofperilunate injury.

OBJETIVO: En este estudio, se evaluaron dieciocho pacientes que tuvieron lesión perisemilunar con dislocación o fractura, y se estudiaron la patomecánica y el tratamiento quirúrgico. SUJETOS Y MÉTODO: Sobre la base de la clasificación de Green y O'Brien, se concluye que ocurrieron las siguientes lesiones: lesión de tipo 1 en un paciente, de tipo 2 en nueve, tipo 4A en cinco, tipo 4C en uno y tipo 4D en uno. El otro caso no se pudo clasificar usando criterios de Green y O'Brien. RESULTADOS: El sistema de puntuación de Evans, indica que se lograron buenos resultados en trece pacientes; resultados satisfactorios en cuatro; resultados pobres en uno; resultados muy pobres en ninguno. Cuando se estimó la patomecánica sobre la base de los criterios Mayfield, diecisiete pacientes fueron clasificados como fase 3. Sin embargo, sólo un caso fue sumamente raro y debe ser clasificado como subtipo de fase 2. CONCLUSIÓN: Los resultados fueron buenos en la mayoría de los pacientes que tuvieron reparación de lesión perisemilunar.

Mechanical Properties of Palmar Radiocarpal Ligaments of Wrist and Their Clinical significances / 대한정형외과학회잡지

To study why the palmar capsular connections between radius and lunate remain intact in perilunate ligamentous injury of the wrist joint, and to compare the material properties of the short radiolunate, long radiolunate, and radioscaphoid region of the radioscaphocapitate ligaments (as the extrinsic ligaments) with those of the intrinsic ligaments of the previous papers, the anatomical and mechanical characteristics of those three palmar radiocarpal ligaments of twenty cadavers were measured and tested by a servo-hydraulic test machine. In spite of its small cross-sectional area (24% of short radiolunate ligament), the radioscaphoid ligament demonstrates a failure load of 58% and a stress of 260% of the short radiolunate ligament, and toughness similar to both the short and long radiolunate ligaments. This suggests that the radioscaphocapitate ligament may contribute as an initial constraint to perilunate injury. The failure load of the scapholunate ligament might be smaller than previously reported due to testing strain rate, which coupled with its short initial length may make it more vulnerable to injury at lower applied loads. The short radiolunate ligament, in spite of the largest width and cross-sectional area, has a failure load and toughness similar to the long radiolunate ligament. The material properties of short and long radiolunate ligaments may explain why the rest of the carpals persistently dislocate or fracture about lunate.