Consistency of AO fracture classification for the distal radius.

We sought to quantify agreement by different assessors of the AO classification for distal fractures of the radius. Thirty radiographs of acute distal radial fractures were evaluated by 36 assessors of varying clinical experience. Our findings suggest that AO 'type' and the presence or absence of articular displacement are measured with high consistency when classification of distal radial fractures is undertaken by experienced observers. Assessors at all experience levels had difficulty agreeing on AO 'group' and especially AO 'subgroup'. To categorize distal radial fractures according to joint displacement and AO type is simple and reproducible. Our study examined only whether distal radial fractures could be consistently classified according to the AO system. Validation of the classification as a predictor of outcome will require a prospective clinical study.

The 2.5 mm PushLock suture anchor system versus a traditional suture anchor for ulnar collateral ligament injuries of the thumb: a biomechanical study.

We compared the biomechanical strength of the 2.5 mm PushLock suture anchor with a traditional Bio-SutureTak suture anchor in repair of ulnar collateral ligament injuries. Iatrogenic ulnar collateral ligament injuries in 18 cadaveric thumbs were repaired and used to test for load to failure and cyclic loading. The average force required to generate a 2 mm gap was 7.7 N for the 2.5 mm PushLock and 6.3 N for the Bio-SutureTak (p = 0.04). The ultimate load to failure was 28.0 N for the 2.5 mm PushLock and 18.8 N for the Bio-SutureTak (p = 0.16). There were no statistical differences between the two suture anchors under cyclic loading. The 2.5 mm PushLock suture anchor provides significantly stronger resistance to 2 mm gap formation at the repair site and is less likely to fail at the suture-ligament interface. However, there was no difference in the load to failure between the two suture anchors.

Intra-articular distal radius fractures: arthroscopic assessment of radiographically assisted reduction.

The optimal means of assessing articular displacement during closed reduction of distal radius fractures is unknown. The purpose of this study was to evaluate the in vivo accuracy of fluoroscopy (C-arm) and plain radiographs (XR) in measuring articular step-off and gap and to determine if postreduction arthroscopy can identify malreduced intra-articular fractures that would benefit from reduction. Fifteen intra-articular distal radius fractures underwent closed manipulation and percutaneous pinning. Reduction was assessed sequentially by C-arm, XR, and wrist arthroscopy. The width of gapping between articular surface fragments was underestimated to a statistically significant degree by both C-arm and XR. The magnitude of articular step-off measured with arthroscopy was not statistically different than that measured radiographically. In 5 (33%) cases, the optimal reduction obtained using C-arm and XR was found to have an articular displacement of >1mm by adjunctive arthroscopy. Complete reduction and pinning was performed with satisfactory results. These results suggest that adjunctive arthroscopy may detect residual gapping of the articular surface that is not seen by C-arm or XR. Residual displacement noted by adjunctive arthroscopy may prompt another reduction effort and result in an improved articular alignment of intra-articular distal radius fractures.

X-ray film measurements for healed distal radius fractures.

In order to understand the effect of malunion on functional outcome, it is essential that deformity be measured in a consistent manner. A standardized method of measuring eight anatomic parameters at the distal radius was developed. By this method, six x-ray films of healed distal radius fractures were subsequently measured by 16 raters. Rater agreement was quantified by using the intraclass correlation coefficient. Tolerance limits were developed in order to estimate the expected margin of error for each parameter. Parameters measured with high rater agreement include ulnar variance, palmar tilt, and radial shift; however, even experienced clinicians did not readily agree on the size of step and gap deformity. Using the method of tolerance limits, one would expect that two randomly chosen clinicians measuring step and gap deformity on a random x-ray film will differ by more than 3 mm at least 10% of the time. Similarly, repeat step or gap measurements by the same observer are expected to differ by more than 2 mm at least 10% of the time. In view of our inability to measure deformity more accurately, the concept of a specific relationship between a given degree of deformity and outcome must be questioned. Prospective research is needed in order to improve our understanding of the precise relationship between malunion and functional outcome.