Four-corner arthrodesis concentrator of Ni-Ti memory alloy for carpal collapse

Surgical fixation techniques in four-corner fusion of the wrist: a systematic review of 1103 cases

BACKGROUND

Four-corner fusion (4CF) is a known treatment option for degenerative wrist conditions. Different techniques may be used and there is no general consensus on best implant. As such, it was the purpose of the current systematic review to compare fusion rates and outcomes depending on the fixation technique.

METHODS

The systematic review was registered in the international prospective register of systematic reviews (PROSPERO): CRD42020164301. It followed the PRISMA guidelines. Original articles were screened using the following databases: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and Web of Science Core Collection. Studies reporting on outcome for 4CF surgery were included. Studies with a minimum Level IV of evidence were considered eligible. Quality assessment was performed using the Methodological Index for Non-Randomized Studies (MINORS) criteria.

RESULTS

A total of 29 studies met the inclusion criteria, for a total of 1103 wrists. The mean age was 41.8 years (range 19-83). Mean follow-up overall was 43.5 months (range 24-146 months). Reported fusion weighted rates were >90% and did not differ significantly between techniques. Reoperations due to different reasons occurred in 135 (12%) of all 1103. There was significant data heterogeneity regarding fusion rates (I² = 70%). Inconsistency and heterogeneity in data reporting did not allow meta-analysis with direct data pooling and comparison of subgroups.

CONCLUSIONS

Satisfactory fusion rates (over 90%) can be achieved independent of the fixation technique used in 4-corner arthrodesis. Due to the high data heterogeneity and reporting inconsistency across studies, no statements regarding PROMs, ROM or grip strength can be made.

LEVEL OF EVIDENCE

Systematic Review of Level IV Studies.

Early motion following 4-corner arthrodesis using cannulated compression screws: a biomechanical study

PURPOSE

To assess the ability of headless compression screws to maintain immobile bony contact throughout wrist cycling following simulated 4-corner arthrodesis. Our hypothesis was that the screw constructs would not permit displacement of the carpal bones and, therefore, could tolerate early postoperative range of motion in vivo.

METHODS

Using 6 matched-paired cadaveric arms, 4-corner arthrodesis was performed using an all-cannulated compression screw construct (capitolunate, lunotriquetral, and triquetrohamate screws) or a partial compression screw combined with partial K-wire construct (2 crossing capitolunate screws with the lunotriquetral and triquetrohamate interfaces immobilized with 2 K-wires). Wrists were mounted and cycled 5,000 times. Intercarpal distances were measured at 0, 100, 1,000, and 5,000 cycles at fixed points of passive flexion. Because previously published studies considered intercarpal distances of greater than 1 mm as significant, we defined fixation failure as greater than 0.5 mm gapping.

RESULTS

Neither screw construct showed any significant intercarpal gapping at any point during the experimental cycling (largest average intercarpal gapping was 0.2 mm). There were no significant differences between the constructs regarding gapping at any point.

CONCLUSIONS

In this biomechanical model, cannulated compression screws effectively resist significant intercarpal gapping during early motion after 4-corner arthrodesis. This may allow for immediate postoperative range of motion.

CLINICAL RELEVANCE

Early gentle range of motion may be possible immediately following 4-corner arthrodesis using a construct consisting of headless compression screws.