Fixed Lunate Flexion Deformity in Distal Radius Fractures

Three-Dimensional Morphometric Analysis of the Volar Cortical Shape of the Lunate Facet of the Distal Radius

In cases of distal radius fractures, the fixation of the volar lunate facet fragment is crucial for preventing volar subluxation of the carpal bones. This study aims to clarify the sex differences in the volar morphology of the lunate facet of the distal radius and its relationship with the transverse diameter of the distal radius. Sixty-four CT scans of healthy wrists (30 males and 34 females) were evaluated. Three-dimensional (3D) images of the distal radius were reconstructed from the CT data. We defined reference point 1 as the starting point of the inclination toward the distal volar edge, reference point 2 as the volar edge of the joint on the bone axis, and reference point 3 as the volar edge of the distal radius lunate facet. From the 3D coordinates of reference points 1 to 3, the bone axis distance, volar-dorsal distance, radial-ulnar distance, 3D straight-line distance, and inclination angle were measured. The transverse diameter of the radius was measured, and its correlations with the parameters were evaluated. It was found that in males, compared to females, the transverse diameter of the radius is larger and the protrusion of the volar lunate facet is greater. This suggests that the inclination of the volar surface is steeper in males and that the volar locking plate may not fit properly with the volar cortical bone of the lunate facet, necessitating additional fixation.

Traumatic Volar Carpal Instability Nondissociative: A Case Series

Carpal instability nondissociative (CIND) involves disruption between carpal rows from injury to extrinsic and intrinsic wrist ligaments. CIND traumatic (CINDT) highlights the posttraumatic etiology of some of these cases and has been gaining increasing attention in the literature. We present four cases of CINDT-volar intercalated segmental instability (VISI). We diagnosed two adults with distal radius fractures and two adolescents with Galeazzi fractures, all treated surgically, who developed CINDT-VISI with radiolunate angles greater than 15° at 2 weeks after surgery. One adult had progressive deformity but was asymptomatic at 33 months. The other underwent volar capsular release at 1 year to improve alignment. One adolescent with a fixed deformity required soft tissue releases and temporary pinning to restore alignment at 7 months. We treated the other successfully with early physiotherapy. No patient had radiographic signs of arthritis at 1-2 years. This is the first reported association between Galeazzi fractures and CINDT-VISI. Contrary to existing literature, we report successful outcomes with nonsurgical and delayed nonfusion surgery of CINDT-VISI.

[Carpal Malalignment in Malunited Fractures of the Distal Radius]

PURPOSE

To evaluate and classify carpal alignment in malunited fractures of the distal radius.

MATERIALS AND METHODS

On standardized lateral radiographs of the involved wrist of 72 patients with a symptomatic extra-articular malunion of the distal radius, 43 with a dorsal and 29 with a palmar angulation, radius tilt (RT), radiolunate (RL) and lunocapitate angle were measured. Malposition of the radius was defined as RT plus 11° in dorsal malunion and RT minus 11° in palmar malunion. A palmar tilt of the radius was marked with a minus sign. At the time of corrective osteotomy 9 dorsal malunions underwent for different reasons evaluation of the scapholunate ligament with 4 having a complete scapholunate ligament disruption.

RESULTS

With respect to the RL-angle, carpal malalignment was categorized as follows: type P with a RL-angle less than -12°, type K with a RL-angle between -12 and 10°, type A with a RL-angle more than 10°, but less than the malposition of the radius, type D with a RL-angle greater than the malposition of the radius. All types of carpal malalignment were found in both, dorsally and palmarly tilted malunion. Type A carpal alignment was identified as the leading type in dorsal malunion (25 out of 43 patients), whilst in palmar malunion colinear subluxation of the carpus (type C) was the dominant type (12 out of 29 patients). To return the hand to a neutral position the rotation of the lunate was compensated by a contrarotation of the capitate in the dorsal malunion. In the palmar malunion a dorsal extension of the capitate returned the hand to a neutral position. In 4 of the 5 patients with type D carpal alignment, who had scapholunate ligament evaluation, a complete ligament tear was found.

CONCLUSION

In this study four different types of carpal alignment in malunited extra-articular fractures of the distal radius were identified. Based on this data we suspect that type D carpal alignment in dorsal malunion may be associated with a scapholunate ligament tear. Therefore, we recommend wrist arthroscopy for this group of patients.

Influence of volar margin of the lunate fossa fragment fixation on distal radius fracture outcomes: A retrospective series

BACKGROUND

Distal radius fractures accompanied by the volar margin of the lunate fossa (VMLF) lesions are often overlooked or inadequately reduced in clinical practice.

AIM

To investigate the impact of VMLF fragment in distal radius fractures on the stability and function of the wrist joint.

METHODS

This was a retrospective study of patients with distal radius fractures who underwent surgical treatment between January 2013 and December 2017. The patients were divided into two groups according to whether the VMLF fragments were fixed or not. X-rays and computed tomography were performed before surgery, immediately postoperatively, and at 1, 3, and 6 mo to measure the scapholunate angle, radiolunate angle, capitolunate angle, and effective radiolunate flexion (ERLF). The Mayo wrist score and disabilities of the arm, shoulder, and hand (DASH) score were determined at 1 year.

RESULTS

Thirty-five patients were included. There were 15 males and 20 females. Their mean age was 52.5 ± 14.3 (range: 19-70) years. There were 38 wrists (17 on the left side, 15 on the right, and three bilateral; 16 in the fixed group, and 22 in the unfixed group). The interval between trauma and surgery was from 1 h to 1 mo. The incidence of postoperative wrist instability in the unfixed group (86.4%) was higher than in the fixed group (25.0%) (P ≤ 0.001). Ten patients had ERLF > 25° in the unfixed group and none in the fixed group (P = 0.019). The Mayo wrist score was 94 ± 5.7 in the fixed group and 68 ± 15.1 in the unfixed group (P < 0.001). The DASH score was 4.6 ± 2.5 in the fixed group and 28.5 ± 19.5 in the unfixed group (P < 0.001).

CONCLUSION

Injuries of VMLF, even small fractures, might damage the radial-lunar ligament, leading to postoperative wrist instability, sagittal force line imbalance, and poor recovery of wrist joint function.

Volar Tilt of the Lunate After Open Reduction Internal Fixation of a Distal Radius Fracture

The pathophysiology of carpal adaptations after fracture of the distal radius is incompletely understood. We report 5 patients who had normal carpal alignment on injury radiographs that developed marked volar angulation of the lunate during recovery from volar plate fixation of a fracture of the distal radius. There were no signs of alteration of the carpal ligaments. Two patients had similar volar tilt on the contralateral side. The cause and optimal treatment of carpal malalignment after restoration distal radial alignment are unclear.

Carpal Instability Nondissociative Following Acute Wrist Fractures

PURPOSE

Carpal malalignment following intra-articular fractures has been reported in the literature, with no clear description of possible ligamentous injury leading to the radiological appearance. This study presents a series of patients that developed carpal instability nondissociative (CIND) following acute wrist fractures. The mechanism of injury is postulated by using a cadaveric laboratory investigation.

METHOD

Twelve patients with average age of 32 years were identified with CIND, between 2013 and 2018. Ten patients with a normal carpal alignment in the initial postoperative radiographs exhibited CIND-palmar radiographically at different postoperative periods, and 2 patients showed CIND-dorsal in the initial postoperative x-rays. Four cadaveric specimens were used to validate this injury pattern.

RESULTS

In cadaveric dissections, CIND-palmar could be reproduced by applying an axial loading and dorsal shearing force on a wrist with sequential sectioning of dorsal and palmar extrinsic wrist ligaments. For the intra-articular fractures with CIND-dorsal, the cause is likely a result of volar radiocarpal extrinsic ligament injury combined with intra-articular incongruity of the scaphoid fossa. Eight out of the 12 patients had severe wrist pain and underwent additional surgery. Three patients with reducible CIND-palmar had open capsular repair, and 5 patients with fixed nonreducible malalignment were treated with radioscapholunate arthrodesis. At an average follow-up of 2.3 years, pain relief was noted, together with an improvement in grip strength and range of movement. Radiographically, the wrist alignment was corrected and maintained.

CONCLUSIONS

This article highlights the existence of possible concomitant radiocarpal ligament lesions and residual articular incongruity, associated with acute intra-articular fractures and radiocarpal fracture-dislocations, that destabilize the proximal carpal row into a pattern of nondissociative carpal instability. Early detection of this condition may preserve wrist function by capsular repair, whereas cases with fixed deformity and residual joint incongruity may be best managed with a limited radiocarpal arthrodesis.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic IV.