Biomechanical Comparison of Two Surgical Methods in Treating Stage IIIb Lunate Necrosis

Abstract

This study aims to determine the biomechanical changes and basis for treatment using two surgical methods (scaphotrapeziotrapezoid [STT] fusion and capitoscaphoid [CS] fusion) for stage IIIb lunate necrosis. Eighteen fresh frozen upper extremities of adult cadavers were randomly divided into three groups. In group A, only the radioscaphoid and radiolunate spaces were exposed to place pressure sensors. Groups B and C underwent STT and CS fusion, respectively. The advanced I-scan pressure measurement system was used. Piezoelectric films were placed at the radioscaphoid and radiolunate spaces of wrist joints, and connected to the computerized I-scan system, which was then connected to a biaxial hydraulic material testing system (MTS). Pressure (up to 100 N) was applied to the wrist in inferior neutral position at a 10 N/s compression rate. The pressure distribution, pressure loading, and other data on the radioscaphoid and radiolunate articular surfaces for each sample were dynamically recorded and analyzed. After application of pressure with the wrist in neutral position, the radioscaphoid and radiolunate pressure values of the normal wrist group A were 41.39 ± 6.93 N/cm 2 and 39.22 ± 6.61 N/cm 2 , respectively; those of the STT arthrodesis group B were 83.89 ± 11.27 N/cm 2 and 22.55 ± 11.27 N/cm 2 ; and those of the SC arthrodesis group C were 86.45 ± 8.10 N/cm 2 and 34.11 ± 8.10 N/cm 2 . Compared with CS fusion, STT fusion surgery has much greater value in preventing rotatory semidislocation of the scaphoid bone, as well as in maintaining the stability of the wrist. It is the preferred surgical treatment for stage IIIb lunate necrosis.

Lunatum excision and scaphocapitate arthrodesis in Kienböck’s disease

“…20 Li et al stated in a recent biomechanical study that compared with SCA, STT arthrodesis has much greater value in preventing rotatory semidislocation of the scaphoideum, as well as in maintaining the stability of the wrist. 21 In the present study, SCA was applied following lunatum excision in all patients without significant change in carpal height.…”

Limited Carpal Fusion in Kienböck's Disease: Early Results following Scaphocapitate Arthrodesis

“…SCA and STT arthrodesis shift the load bearing from radiolunate to radioscaphoid joint along with reduction of force transmission at lunocapitate joint. 35 The principle behind SCA in stage III is to arthrodese scaphoid in a favorable position so as to take load off lunate and reduce the nociceptive stimuli arising out of it. 8 SCA was done in all patients in this study with significant change in Note: values are expressed as mean AE standard deviation (range).…”

Managing Kienbock Disease’s Surgical Treatment and Outcome Analysis: A Case Report and Review of Literature

“…Biomechanical investigations have demonstrated that in addition to capitate-hamate-arthrodesis (CHA), SCA and STT arthrodesis resulted in a noteworthy reduction in loading on the lunate [ 13 ]. In a recent biomechanical investigation, Li et al reported that STT arthrodesis is significantly more valuable than SCA in preventing rotatory semi-dislocation of the scaphoid and preserving wrist stability [ 14 ]. In this instance, the patient had SCA after having their lunate removed, and their carpal height did not significantly change.…”