Malunited Colles' fracture. Analysis of stress distribution

[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.

Computational Simulation of Synovial Fluid Kinematics of the Scapholunate Joint

Background: The interaction between wrist kinematics and synovial fluid pressure has yet to be studied. To our knowledge, this is the first study to determine the effect of scapholunate joint kinematics on synovial fluid pressure change using finite volume method. Methods: The carpal bones of a cadaveric hand were obtained from Computed Tomography (CT) scans. CT images of the carpal bones were segmented and reconstructed into 3D model. The 3D synovial fluid model between the scaphoid and lunate was constructed and then used for computational simulations. The kinematics data of scapholunate joint obtained from radioulnar deviation of the wrist was investigated. Results: It was found that the pressure in synovial fluid varied from -1.68 to 2.64 Pa with maximum pressure located at the scaphoid-fluid interface during the radial deviation. For ulnar deviation, the pressure increased gradually from the scaphoid-fluid interface towards the lunate-fluid interface (-1.37 to 0.37 Pa). Conclusions: This new computational model provides a basis for the study of pathomechanics of ligament injury with the inclusion of synovial fluid.

Radiological and Functional Outcome of Displaced Colles' Fracture Managed with Closed Reduction and Percutaneous Pinning: A Prospective Study

Background: Displaced Colles’ fractures are treated by manipulation and below elbow cast application. Malunion is a common complication, resulting in pain, mid-carpal instability, and post-traumatic arthritis. Fracture stabilization by percutaneous pinning is a simple, minimally invasive technique that helps prevent displacement of the fracture, thereby minimizing complications. This study aims to assess the amount of collapse after closed manipulation and percutaneous pinning with Kirschner wires (K-wires) and its correlation with the functional outcome of the wrist after union.

Methods: A prospective study was conducted from May 2015 to May 2016 in a tertiary orthopedic center. Ninety patients (60 females, 30 males) with an average age of 54.93 years with Type II fractures underwent closed manipulation and percutaneous pinning with crossed K-wires as the primary procedure. Serial radiographs were taken to document the amount of collapse. The functional outcome was assessed using the Cooney Wrist Score.

Results: At the final follow-up at six months, the collapse in the mean dorsal angle was 0.94 and mean ulnar variance was 0.51. Functionally, 48 patients (53.33%) had an excellent outcome, 36 patients (40%) had a good outcome, and six patients (6.67%) had a fair outcome.

Conclusions: Displaced Colles’ fractures should be reduced and stabilized with percutaneous K-wires to achieve an excellent functional outcome.

Morphometry of distal end radius in the Indian population: A radiological study

INTRODUCTION

The morphometry of distal end radius (DER) comprises the four necessary parameters: radial inclination, palmer tilt, radial height, and ulnar variance. The unblemished intellect about the morphometry is urged for the management of fracture of DER. The goal of our study was to determine the values of morphometric parameters of the DER from the adult Indian.

MATERIALS AND METHODS

It was a single hospital- based observational cross-sectional, prospective study. Radial inclination, radial height, and ulnar variance were measured on posteroanterior view, and the measurement of palmer tilt was accomplished on the lateral view. All the statistical analysis was done by Microsoft XL 2007 (data add in function were installed for data analysis). T-test was used for comparing the means of the parameters.

RESULTS

Two hundred and forty two (n = 242) X-rays were included in this study to analyze. The mean value (n = 242) of radial inclination was 23.27°± (standard deviation [SD]) 7.42° (range: 11.3-42.1°), palmer tilt 10.07° ± (SD) 5.28° (range: 1-16.9°), radial height 11.31 mm ± (SD) 4.9 mm (range: 7.1-30.4 mm), and ulnar variance 0.66 mm ± (SD) 2.46 mm (range: -2.4 to +4.1).

CONCLUSION

This study may provide an inauguratory plinth to prosecute the further analytical research in the Indian population. Moreover, the data may also be used as a reference data for the anatomical alignment while treating the injuries of the DER in the Indian population.

Treatment of distal radial fractures with antegrade intra-medullary Kirschner wires

The treatment of unstable Colles-type distal radial fractures remains a challenge. A prospective study was conducted to evaluate the outcomes of the treatment of unstable distal radial fractures using antegrade intra-medullary K-wires. Twenty-eight Colles-type distal radial fractures were selected excluding comminuted intra-articular and Barton’s fractures. The blunt tips of intra-medullary K-wires were introduced in an antegrade direction to support the subchondral bone of the distal fragment. The scoring system of Green and O’Brien modified by Cooney et al. was used for the final clinical evaluation. The radiological outcomes were evaluated using the scale proposed by Stewart et al. After a mean follow-up of 34 months (range 14–46), 17 patients were rated clinically excellent, seven good, three fair and one poor. The mean loss of radial height, radial inclination, volar tilt and ulnar variance was 0.9 mm, 1.9°, 0.5° and 0.4 mm, respectively. These results were comparable with the values reported in other pinning studies. Only one patient complained of skin irritation and painful bursitis in the forearm; otherwise, no complications related to tendon or nerve injury were encountered. One patient had protrusion of K-wire into the wrist joint. The technique proved to be effective in maintaining reduction in distal radial fracture with low rate of soft tissue complications.

Comparison of three dimensional and radiographic measurements in the analysis of distal radius malunion

To estimate the accuracy of radiographic deformity evaluation for distal radius malunion, we compared the results obtained from radiographic measurements (palmar tilt, radial angle, and ulnar variance) with those from the three-dimensional (3D) method using computer bone models in 20 dorsally tilted malunions. Dorsal tilt deformity, radial tilt deformity, and shortening deformity were calculated using the unaffected side as a reference. The 3D method showed a slightly lower value for dorsal tilt deformity than the radiographic evaluation, but the difference was < 10° in all cases. In patients with dorsal tilt ≥ 40°, notable differences in radial tilt evaluation were observed between the two methods compared with patients with less dorsal tilt. The 3D shortening showed positive correlations with radiographic evaluation, but a discrepancy of ≥ 2 mm was observed in eight cases. Palmar tilt is reliable for surgical planning, but radial angle and ulnar variance may be less accurate than previously thought.

Correction of dorsally-malunited extra-articular distal radial fractures using volar locked plates without bone grafting

Malunion is the most common complication of the distal radius with many modalities of treatment available for such a problem. The use of bone grafting after an osteotomy is still recommended by most authors. We hypothesised that bone grafting is not required; fixing the corrected construct with a volar locked plate helps maintain the alignment, while metaphyseal defect fills by itself. Prospectively, we performed the procedure on 30 malunited dorsally-angulated radii using fixed angle volar locked plates without bone grafting. At the final follow-up, 22 wrists were available. Radiological evidence of union, correction of the deformity, clinical and functional improvement was achieved in all cases. Without the use of bone grafting, corrective open wedge osteotomy fixed by a volar locked plate provides a high rate of union and satisfactory functional outcomes.

Three-dimensional deformity analysis of malunited distal radius fractures and their influence on wrist and forearm motion

Little information exists about three-dimensional (3-D) deformity patterns of malunited distal radius fractures including axial deformity. The current study aimed to clarify the 3-D deformity pattern of malunited distal radius fractures and reveal the influence of osseous deformities, including axial rotation deformity, on wrist and forearm motion. The deformity of 20 dorsally tilted malunions were evaluated using 3-D computer models created from CT data, and correlations between deformity components and range of motion were assessed. The 3-D deformity analysis showed that axial malalignment in pronation, which showed a correlation with the degree of radial tilt deformity, was very common. A radial tilt deformity of > 5° was observed in only 45% of cases. Although the range of wrist flexion and extension showed a correlation with dorsal tilt deformity, the range of forearm pronation and supination did not correlate with distal radius deformities.

OUTCOME OF UNSTABLE DISTAL RADIUS FRACTURES TREATED WITH OPEN REDUCTION AND INTERNAL FIXATION VERSUS EXTERNAL FIXATION

The objective of this study was to compare the clinical results of unstable distal radius fractures treated with ORIF with plate and screws compared to EF. Patients with unstable distal radius fractures treated with ORIF or EF from January 2005 to December 2010 were reviewed in terms of the Modified Mayo Wrist Score, range of motion, pain, grip strength, and radiologic parameters. Results showed that there was no difference in the Modified Mayo Wrist Score between ORIF (17 patients) and EF (11 patients) (p = 0.07). The ORIF group had better wrist flexion, wrist extension, pronation and supination compared to the EF group (p < 0.05). There were no significant differences in terms of radial and ulnar deviation, grip strength, pain and postoperative radiologic parameters (p < 0.05). Better wrist flexion, wrist extension and forearm rotation can be expected in ORIF compared to EF in the management of unstable distal radius fractures.

Malunion of the distal radius

Fractures of the distal radius are extremely common injuries, which are steadily becoming a public health issue. One of the most common complications following distal radius fractures is still malunion of the distal radius. This review of the literature surrounding distal radius malunion covers the biomechanics of distal radial malunion, treatment options, indications for surgery, surgical techniques, and results.

The effect of distal radius locking plates on articular contact pressures

PURPOSE

Fractures of the distal radius are among the most common injuries treated in hand surgery practice, and distal radius locking plates have become an increasingly popular method of fixation. Despite widespread use of this technology, it is unknown whether the subchondral placement of locking screws affects the loading profile of the distal radius. Our study was designed to determine whether subchondral locking screws change the articular contact pressures in the distal radius.

METHODS

Twelve cadaveric forearms underwent a previously described axial loading protocol in a materials testing machine. We used an intra-articular, real-time computerized force sensor to measure peak contact pressure, total pressure, and contact area in the distal radius. Internal validation of sensor placement and reproducibility was conducted. Each specimen was tested before fixation (control), after application of a palmar distal radius locking plate, and after simulation of a metaphyseal fracture.

RESULTS

We identified no statistically significant differences in maximum pressure, total pressure, and contact area among control, plated, and plated and fractured specimens. However, the contact footprint-represented by squared differences in force across the sensor-were significantly different between the control group and both plated groups.

CONCLUSIONS

The technique for measuring contact pressures produces highly repeatable values. Distal radius locking plates with subchondral hardware placement do not seem to significantly change articular contact pressures.

Management of post-traumatic malunion of fractures of the distal radius

Distal radius malunions are a common cause of patient morbidity. This review of the literature surrounding distal radius malunion covers the demographics, pathologic anatomy, and indications for surgery, surgical techniques, and salvage options. Particular emphasis is placed on subject areas that have not been reviewed as extensively in previous articles, including: intra-articular malunion, computer-assisted techniques, bone graft alternatives, and volar fixed-angle plate osteosynthesis.

Late collapse of distal radius fractures after K-wire removal: is it significant?

BACKGROUND

The aim of this study was to find out whether distal radius fractures treated by Kirschner wire (K wire) fixation loose reduction after wire removal and analyze the variables may influence this.

MATERIALS AND METHODS

Patients who underwent K wire fixation for unstable fractures of distal radius over a period of 3 years were included in this retrospective study. Fractures were classified according to AO classification. Radiographs taken just prior to removal of K wires and radiographs taken at least 1 month after wire removal were analyzed to study three radiological parameters; Palmar or dorsal tilt, radial inclination and ulnar variance. Loss of these angles was analyzed statistically against variables like age, sex, AO classification and duration of fixation.

RESULTS

59 fractures were analyzed with mean age of 56 years and male to female ratio of 1:2. Average loss of radial tilt was 2.6 degrees , loss of palmar tilt was 2.6 degrees and loss of ulnar variance was 1.3 mm.

CONCLUSIONS

We found that distal radius fractures treated by percutaneous K wire fixation, did not suffer significant loss of reduction of fracture position after removal of wires. This remains true regardless of age, sex, fracture type according to AO type or duration of wire fixation.

Corrective osteotomy for deformity of the distal radius using a volar locking plate

Dorsally angulated malunions of the distal radius have historically been corrected with an opening wedge osteotomy fixed with a dorsal plate. Volar locking plates may facilitate a less morbid approach to corrective osteotomies of the wrist. Eight consecutive patients with an average age of 40 years (range, 15-52 years) underwent correction of a distal radius deformity through a volar approach. Clinical follow-up averaged 17.4 months (range, 7-41 months). Preoperative radiographs revealed an average of 24 degrees of dorsal tilt in patients with dorsal deformity. Postoperatively, their average measurement was <3 degrees of volar tilt. Patients were initially ulnar-positive with an average of 4 mm ulnar-positive variance (range, 2-7 mm). This corrected to less than 1 mm postoperatively. Postoperative disabilities of the arm, shoulder, and hand (DASH), SF-12, and Mayo Wrist scores averaged 10.8, 40.5, and 82.5, respectively. There were no nonunions, and no plates required removal. Distal radius deformity can be effectively addressed through a volar approach with the use of a locking plate.

Management of post-traumatic malunion of fractures of the distal radius

Distal radius malunions are a common cause of patient morbidity. This review of the literature surrounding distal radius malunion covers the demographics, pathologic anatomy, and indications for surgery, surgical techniques, and salvage options. Particular emphasis is placed on subject areas that have not been reviewed as extensively in previous articles, including: intra-articular malunion, computer-assisted techniques, bone graft alternatives, and volar fixed-angle plate osteosynthesis.

Extra-articular distal radial fracture malunion

With the increase in surgical options for the treatment of distal radius fractures, the authors anticipate that distal radial fracture malunions will be a less frequently seen problem. Nevertheless, they will still occur. Although patient selection has been weighted toward the younger patient, we believe that surgery should be based on patient activity level, functional needs, and disability related to the malunion. With advances in biotechnology and improved anesthetics, surgical intervention even in the older and osteopenic population is now more promising. Surgical intervention still requires appropriate patient selection, careful preoperative planning, and meticulous surgical technique. The appropriate surgical procedure should be tailored to the patient's symptoms, age, needs, and radiographic findings.

Corrective osteotomy of the distal radius through volar approach

Operative correction through the malunion has become a well-accepted reconstructive procedure for symptomatic malunited extra-articular fractures of the distal radius over the last 3 decades. Now that newer plates designed specifically for the volar fixation of dorsally unstable distal radius fractures by incorporating buttress pins and screws that lock to the plate are available, more and more surgeons prefer volar fixation of dorsally unstable distal radius fractures. In the mid 1970s, the senior author (U.B.L.) developed a technique for corrective osteotomy of dorsally tilted malunions of the distal radius using a radiovolar approach and a special plate. This technique was proved to be efficient in more than 400 patients.

Rotational deformity in malunited fractures of the distal radius

PURPOSE

To evaluate rotational deformity in malunited fractures of the distal radius and its effect on forearm rotation.

METHODS

Thirty-seven patients with a symptomatic malunion of the distal radius (25 with dorsal angulation and 12 with volar angulation) were assessed for rotational deformity of the distal fragment. Spiral computed tomographic scans were taken of both wrists. Rotational deformity was evaluated by comparing the radial torsion angle of the injured and uninjured sides according to Frahm. Multivariable regression analyses were used to identify the radiologic parameter that had the most important influence on forearm rotation.

RESULTS

Of the 37 patients, 23 showed a rotational deformity of the distal radius. In both dorsally and volarly angulated malunions, pronation and supination deformities were identified. There was a tendency toward more pronation deformities with volar malunion. Volar angulated malunion with a rotational deformity of less than 10 degrees showed the smallest amount of forearm supination. Losses of pronation-supination did not correlate with the amount of rotational deformity.

CONCLUSIONS

This study showed that rotational deformity is common with angulated malunions of the distal radius. The effect on forearm rotation should not be overestimated. Pretreatment computed tomographic scanning of both wrists to identify and measure malrotation of the distal radius may be helpful to improve the outcome after corrective osteotomy.

Kinematic and torque-related effects of dorsally angulated distal radius fractures and the distal radial ulnar joint

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Analysis of stress distribution in the humeroradial joint

Stress distribution in the humeroradial joint was analyzed with pressure-sensitive film, a tactile sensor, and by the three-dimensional finite element method. Fifteen cadaveric elbows with minimal osteoarthritic changes were loaded perpendicular to the articular surface of the radial head in the full pronation, supination, and neutral positions from 0 degrees to 90 degrees. Finite element analysis of stress distribution in the joint was based on a model of the same conditions. The patterns of stress distribution were similar with all three analysis methods. High stress was concentrated laterally in supination, and medially in the neutral and pronation positions. The results of the analyses closely resembled those found in some studies of the pathophysiology of degenerative changes in the humeroradial joint.

Load transfer analysis of the distal radius from in-vivo high-resolution CT-imaging

Prevention of osteoporotic bone fractures requires accurate diagnostic methods to detect the increase in bone fragility at an early stage of osteoporosis. However, today's bone fracture risk prediction, primarily based on bone density measurement, is not sufficiently precise. There is increasing evidence that, in addition to bone density, also the bone microarchitecture and its mechanical loading conditions are important factors determining the fracture risk. Recently, it has been shown that new high-resolution imaging techniques in combination with new computer modeling techniques based on the finite-element (FE) method can account for these additional factors. These techniques might provide information that is more relevant for the prediction of bone fracture risk. So far, however, these new imaged-based FE techniques have not been feasible in-vivo. The objectives of this study were to quantify the load transfer through the trabecular network in a distal radius using a computer model based on in-vivo high-resolution images and to determine if common regions of fractures can be explained as a result of high tissue loading in these regions. The left distal radius and the two adjacent carpal bones of a healthy volunteer were imaged using a high-resolution three-dimensional CT system providing an isotropic resolution of 165 microm. The bone representation was converted into a FE-model that was used to calculate stresses and strains in the trabecular network. The two carpal bones were loaded using different load ratios (for each load case 1000 N in total) representing impact forces on the hand either in near-neutral position or ulnar/radial deviation. The load transfer through the trabecular network of the radius was characterized by the tissue strain energy density (SED) distribution for all load cases. It was found that the distribution of the tissue loading depends on the ratio of the forces acting on the carpal bones. For all load cases the higher SED values (on average: 0.02 +/- 0.08 (S.D.) N mm(-2)) are found in a 10 mm region adjacent to the articular surface which corresponds well with the region where Colles- or Chauffeur-fractures occur. We expect that, eventually, this new approach can lead to a better prediction of the fracture risk than methods based on bone density alone since it accounts for the bone microstructure as well as its loading conditions.