vendex and Radius-Fractures

Although distal radius fractures (DRF) are frequent, the management of associated ulnar styloid process (USP) lesions is still controversial. According to recent studies, a fracture of the USP does not appear to affect functional outcomes after treatment of a DRF with plate fixation. We sought to compare the impact of a USP fracture on pronation and supination strength in isometric and isokinetic tests. We included patients with a DRF who underwent volar locking plate fixation. We divided our population into three groups: one group consisted of patients who had a fracture of the USP base, one group composed of patients without USP fracture or with a distal ulnar fracture only, and a control group composed of subjects with normal wrists. Inclusion criteria included an age of 18 to 50 years and a minimum follow-up of 10 months post-surgery. The main exclusion criteria were complex intraarticular fractures and postoperative complications. The assessment was based on clinical examination and recording of forearm rotation strength during pronation and supination in isokinetic and isometric tests. The ratio between the operated and contralateral sides was compared for each patient. Thirty-six participants were included (mean age 31.1±4.5 years). The mean postoperative follow-up was 17.9±6.9 months. Participants with a USP fracture differed from other participants in their peak torque on the isokinetic test at 45°/s for pronation and supination, but not on isokinetic tests at 120°/s or in isometric tests. Isokinetic tests revealed a decrease in pronation-supination strength during sustained effort for patients with associated basal USP fractures. These findings may have clinical implications for management of the USP but need to be specified with further study. LEVEL OF EVIDENCE: prognostic study level III.

Topics: Adult; Bone Plates; Case-Control Studies; Female; Fracture Fixation, Internal; Humans; Male; Pronation; Radius Fractures; Retrospective Studies; Supination; Torque; Ulna Fractures; Wrist Joint

To measure the effects of distal radius malalignment on loading at the distal ulna.. Using an adjustable mechanism to simulate angulated and translated malalignments, clinically relevant distal radius deformities were simulated in a cadaveric model. A custom-built load cell was inserted just proximal to the native ulna head to measure the resultant force and torque in the distal ulna. Loads were measured before and after transecting the triangular fibrocartilage complex (TFCC).. There was an increase in distal ulna load and torque with increasing dorsal translation and angulation. Combined conditions of angulation and translation increased force and torque in the distal ulna to a greater extent than with either condition in isolation. Transecting the TFCC resulted in a reduction in distal ulna load and torque.. A progressive increase in load at the distal ulna was observed with increasing severity of malalignment, which may be an important contributor to residual ulnar wrist pain and dysfunction. However, no clear-cut threshold of malalignment of a dorsally angulated and translated distal radius fracture was identified. These observations suggest that radius deformities cause articular incongruity, which increases TFCC tension and distal radioulnar joint load. Cutting of the TFCC decreased distal ulna loading, likely by releasing the articular constraining effect of the TFCC on the distal radioulnar joint, allowing the radius to rotate more freely with respect to the ulna.. Anatomical reduction of a distal radius fracture minimizes the forces in the distal ulna and may reduce residual ulnar wrist pain and dysfunction.

Topics: Aged; Aged, 80 and over; Biomechanical Phenomena; Female; Fractures, Malunited; Humans; Male; Middle Aged; Models, Biological; Radius Fractures; Torque; Triangular Fibrocartilage; Ulna; Weight-Bearing; Wrist Injuries

Open reduction and internal fixation of distal radius fractures often necessitates release of the brachioradialis from the radial styloid. However, this common procedure has the potential to decrease elbow flexion strength. To determine the potential morbidity associated with brachioradialis release, we measured the change in elbow torque as a function of incremental release of the brachioradialis insertion footprint.. In 5 upper extremity cadaveric specimens, we systematically released the brachioradialis tendon from the radius and measured the resultant effect on brachioradialis elbow flexion torque. We defined release distance as the distance between the release point and the tip of the radial styloid.. Brachioradialis elbow flexion torque dropped to 95%, 90%, and 86% of its original value at release distances of 27, 46, and 52 mm, respectively. Importantly, brachioradialis torque remained above 80% of its original value at release distances up to 7 cm.. Our data demonstrate that release of the brachioradialis tendon from its insertion has minor effects on its ability to transmit force to the distal radius.. These data imply that release of the distal brachioradialis tendon during distal radius open reduction internal fixation can be performed without meaningful functional consequences to elbow flexion torque. Even at large release distances, overall elbow flexion torque loss after brachioradialis release would be expected to be less than 5% because of the much larger contributions of the biceps and brachialis. Use of the brachioradialis as a tendon transfer donor should not be limited by concerns of elbow flexion loss, and the tendon could be considered as an autograft donor.

Topics: Aged; Aged, 80 and over; Biomechanical Phenomena; Elbow Joint; Female; Humans; Male; Middle Aged; Radius Fractures; Suture Techniques; Tendons; Torque

Pronator quadratus (PQ) is an important contributor to forearm pronation, and there is concern that volar plating of a distal radius fracture (DRF) may damage the PQ function. The purpose of this study was to determine whether isokinetic pronation strength would decrease considerably after volar locking plating of a DRF, and whether clinical outcomes would be affected by any pronation strength decrease.. Thirty-four patients of mean age of 55 years (range, 21-74 years) underwent bilateral isokinetic testing at 6 months and 1 year after open reduction and internal fixation using volar plating. Isokinetic pronation and supination strengths were compared between the operated and normal sides. Clinical outcomes such as grip strengths, range of motions and disabilities of the arm, shoulder and hand (DASH) scores were evaluated and analysed for any associations with isokinetic results.. At 6 months, peak torque and total work values for both pronation and supination were lower in the operated sides than in the normal sides (all p < 0.001). However, at 1 year postoperatively, the differences in pronation strength were not statistically significant (p = 0.188 for peak torque and p = 0.190 for total work), whilst supination torque and total work were still significantly lower in the operated sides (p = 0.015 and p = 0.029, respectively). Decreases in pronation strength were found to correlate significantly with decreases in supination strength and grip power. Wrist motion and DASH scores were not found to be correlated with decrease in pronation or supination strengths.. In patients with a DRF treated by volar plating, pronation strength was not significantly different between the operated and normal sides at 1 year postoperatively, and decreases in pronation or supination strengths were not found to affect clinical outcomes as assessed by DASH scores. This study suggests that dissection of the PQ may have minimal clinical impact on forearm pronation function.

Topics: Adult; Aged; Bone Plates; Female; Follow-Up Studies; Forearm; Fracture Fixation, Internal; Hand Strength; Humans; Male; Middle Aged; Palmar Plate; Pronation; Radiography; Radius Fractures; Range of Motion, Articular; Retrospective Studies; Supination; Surveys and Questionnaires; Torque; Treatment Outcome; Young Adult

Distal radius fractures represent the most common fractures in adult individuals. Volar fixed-angle plating has become a popular modality for treating unstable distal radius fractures. Most of the plates allow insertion of either threaded locking screws or smooth locking pegs. To date, no biomechanical studies compare locking screws and pegs under axial and torsional loading.. Ten Sawbones radii were used to simulate an AO/OTA A3 fracture. Volar fixed-angle plates (Aptus Radius 2.5, Medartis, Switzerland) with threaded locking screws (n = 5) or smooth locking pegs (n = 5) were used to fix the distal metaphyseal fragment. Each specimen was tested under axial compression and under torsional load with a servohydraulic testing machine. Qualitative parameters were recorded as well as axial and torsional stiffness, torsion strength, energy absorbed during monotonic loading and energy absorbed in one cycle.. Axial stiffness was comparable between both groups (p = 0.818). If smooth pegs were used, a 17% reduction of torsional stiffness (p = 0.017) and a 12% reduction of minimum torque (p = 0.012) were recorded. A 12% reduction of energy absorbed (p = 0.013) during monotonic loading and unloading was recorded if smooth pegs were used. A 34% reduction of energy absorbed in one cycle (p < 0.007) was recorded if threaded screws were used. Sliding of the pegs out of the distal radius metaphyses of the synthetic bones was recorded at a mean torque of 3.80 Nm ± 0.19 Nm. No sliding was recorded if threaded screws were used.. According to the results of this study using Sawbones, volar fixed-angle plates with threaded locking screws alone are mechanically superior to volar fixed-angle plates with smooth locking pegs alone under torsional loading.

Topics: Biomechanical Phenomena; Bone Plates; Bone Screws; Cadaver; Fracture Fixation, Internal; Humans; Palmar Plate; Prosthesis Design; Radius; Radius Fractures; Torque; Weight-Bearing; Wrist Joint

The purpose of the study was to compare the biomechanical stability of distal radius fracture fixation with 2 new implants, the DNP (Hand Innovations LLC, Miami, FL), a dorsal locked hybrid of nail and plate, and the XSCREW (Zimmer, Freiburg, Germany), an implant combining a cannulated screw and K-wires, in a cadaver bone distal radius fracture model.. Eight pairs of fresh-frozen cadaver radii were used. To simulate an extra-articular distal radius fracture, a 5-mm volar open wedge osteotomy was made. Axial loads of 10 to 100 N and torque loads of -1.5 to 1.5 Nm were applied by a testing machine to the intact radii and to the radii after each device was fixed as recommended by the manufacturer. One thousand cycles in torque and failure tests were performed.. With a median of 136.0 N/mm, the axial stiffness of XSCREW-fixed specimens was higher than that of DNP-fixed specimens, with a median of 69.5 N/mm, but differences were not statistically significant. With a median of 0.163 Nm/ degrees , the torque stiffness of XSCREW-fixed specimens was significantly higher than that of DNP-fixed specimens, with a median of 0.068 Nm/ degrees . The XSCREW-group reached 33% of the axial stiffness and 49% of the torque stiffness of the intact radii, and the DNP-group reached 14% of the axial stiffness and 20% of the torque stiffness of the intact radii.. In this human cadaver bone biomechanical study, the XSCREW provided more stability than the DNP in torque stiffness but not in axial stiffness.

Topics: Aged; Aged, 80 and over; Biomechanical Phenomena; Bone Plates; Bone Screws; Bone Wires; Cadaver; Female; Fracture Fixation, Internal; Humans; Male; Prosthesis Design; Prosthesis Failure; Radiography; Radius Fractures; Statistics, Nonparametric; Stress, Mechanical; Torque

Obtaining sufficient fracture fixation in osteoporotic bone is challenging. The purposes of the current study were (1) to compare the pullout strength of a 4-mm cancellous screw (cancellous screw group) with that of a 3.5-mm cortical screw (cortical screw group), and (2) to measure the pullout strength of a 4-mm cancellous screw placed as a rescue screw (rescue screw group) in a stripped 3.5-mm cortical screw (stripped screw group) hole while controlling for bone density and cortical thickness.. We inserted 4 screws, one from each experimental group, into 11 osteoporotic cadaveric radii, while recording the insertion torque. Radii were mounted on a servohydraulic testing machine, and each screw was pulled out at a rate of 5 mm/min. Pullout strength was recorded. The effects of cortical thickness (near, far, and total), bone density, insertion torque, and the experimental screw group (cortical, cancellous, stripped, and rescue screw groups) on pullout strength were analyzed using multiple linear regression with random effects. Statistical significance was set at P < 0.05.. There was no significant difference in pullout strength between the cortical and cancellous screw groups. The rescue screw group had significantly less pullout strength than did the cortical and cancellous screws, and only partly increased pullout strength compared with stripped screws. Bone density significantly affected pullout strength, but insertion torque and cortical thickness were not significant covariates.. There seems to be no advantage in using a cancellous screw over a cortical screw in bicortical fixation in osteoporotic bone. Although the rescue screw provided greater pullout strength than the stripped screw, it is unknown if the purchase it provides is clinically sufficient.

Topics: Aged; Aged, 80 and over; Biomechanical Phenomena; Bone Screws; Cadaver; Equipment Failure Analysis; Female; Fracture Fixation, Intramedullary; Humans; Male; Osteoporosis; Radius Fractures; Torque

The purpose of this study was to compare the fixation afforded by a dorsal nonlocking plate with a volar locking plate in a fracture model simulating an extra-articular distal radius fracture with dorsal comminution (OTA [Orthopaedic Trauma Association] type 23-A3.2).. In 10 matched pairs of fresh-frozen cadaveric arms, a comminuted extra-articular dorsally unstable distal radius fracture (OTA type 23-A3.2) was created. The fractures were fixed with either dorsally placed nonlocking T-plate or volarly placed locking plate within matched pairs. The precycling stiffness with axial and torsional loading of the specimens was determined. The specimens were then loaded axially for 5000 cycles, and postcycling axial and torsional stiffness and load to failure were determined.. The mean axial and torsional stiffness before and after cyclic loading of fractures stabilized with dorsal nonlocking plate was not significantly different than fractures fixed with volar locking plate. Although the mean load to failure was greater for the volar locking plate group than dorsal nonlocking plate group, the difference was not significant.. This study suggests that the fixation obtained with volar locking plates is as stable as fixation with a dorsal plate in acute healing period and can withstand the functional demands of the immediate postoperative period in dorsally comminuted unstable extra-articular distal radius fractures. Elimination of dorsal tendinopathy by using volar locking plates may lead to fewer long-term complications. Locking plates provided better stability in specimens with osteoporosis.

Topics: Aged; Aged, 80 and over; Bone Plates; Cadaver; Elastic Modulus; Female; Fracture Fixation, Internal; Humans; Joint Instability; Male; Middle Aged; Radius; Radius Fractures; Stress, Mechanical; Torque

The purpose of this study was to examine the torque required to achieve a full range of motion of the distal radioulnar joint (DRUJ) as a result of increasing dorsal angulation from simulated fractures of the distal radius. Based on this study the accepted amount of dorsal angulation of the distal radius can be determined.. In 9 fresh cadaver limbs motion of the DRUJ was simulated by a custom motion and loading forearm device. The malunion model of the distal radius was controlled by a specially designed external fixation frame that provided control in 6 degrees of dorsal angulations (N, 0 degrees, 10 degrees, 20 degrees, 30 degrees, and 40 degrees ). The study included an intact and nonintact triangular fibrocartilage complex.. This study showed that torque across the DRUJ was affected by the degree of simulated malunion of the distal radius. With more than 30 degrees dorsal angulation the torque across the DRUJ was increased in both muscle loading and unloading conditions. Although significance was not noted, with resistive loading this study showed torque changes with as little as 10 degrees malunion of the distal radius.. We conclude that reduction of distal radius fractures to within 10 degrees of dorsal angulation is needed to allow patients to maintain full forearm and wrist rotation.

Topics: Aged; Aged, 80 and over; Female; Fractures, Malunited; Humans; Male; Middle Aged; Models, Biological; Pronation; Radius Fractures; Range of Motion, Articular; Torque; Ulna; Weight-Bearing; Wrist Joint