Image-Based Comparison Between the Bilateral Symmetry of the Distal Radii Through Established Measures

Three-Dimensionally Planned and Printed Patient-Tailored Plates for Corrective Osteotomies of the Distal Radius and Forearm

PURPOSE

We evaluated the 1-year postoperative clinical and patient-reported outcomes in patients who had a 3-dimensional planned corrective osteotomy of their distal radius, radial shaft, or ulnar shaft using a printed, anatomical, patient-tailored plate to determine the feasibility and effectiveness of this methodology.

METHODS

Simulations in computer-assisted preoperative planning of corrective osteotomies resulted in 3-dimensionally printed surgical guides, surgical models, and anatomically customized plates for application at the distal radius and forearm. Patients with malunions of the distal radius or forearm who underwent fixation with the custom-made plates were documented in our registry. Grip strength and range of motion assessments were made before surgery (baseline), as well as at 6 weeks and 3 and 12 months. Additionally, patients rated their wrist-related pain and disability using the Patient-Rated Wrist Evaluation.

RESULTS

Fifteen patients underwent corrective surgery, and the 1-year follow-up data of 14 patients with a median age of 56 years (interquartile range, 24-64 years) were available for analysis. The median baseline Patient-Rated Wrist Evaluation score improved from 47 to 7 after 1 year. The flexion-extension arc of motion of the wrist increased from 90° at baseline to 130° at 1 year and the pronation-supination arc of motion of the wrist increased from 135° to 160° in the same time period. Differences in radiological measurements for palmar and radial inclinations, as well as for ulnar variance between the affected and contralateral wrists, were reduced with the osteotomy. In 1 case, the plate was removed 11 months after the osteotomy. No severe adverse events were reported.

CONCLUSIONS

Three-dimensionally planned and printed patient-tailored plates offer a reliable method for correcting even complex malunions of the distal radius and forearm.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

An Evaluation of the Reliability of Manual Landmark Identification on 3D Segmented Wrists

BACKGROUND

Three-dimensional (3D) preoperative planning is increasingly used in orthopaedic surgery. Two-dimensional (2D) characterization of distal radial deformities remains inaccurate, and 3D planning requires a reliable reference frame at the wrist. We aim to evaluate the reliability of the determination of anatomical points placed manually on 3D models of the radius to determine which of those points allow reliable morphometric measurements.

METHODS

Twenty-three radial scans were reconstructed in 3D. Five operators specialized in the upper limb manually positioned 8 anatomical points on each model. One of the operators repeated the operation 6 times. The anatomical points were based on previously published 3D models used for radial inclination and dorsopalmar tilt measurements. The repeatability and reproducibility of the measurements derived using this manual landmarking were calculated using different measurement methods based on the identified points. An error of ≤2° was considered clinically acceptable.

RESULTS

This study of intraobserver and interobserver variability of the anatomic points allowed us to determine the least variable and most accurately defined points. The middle of the ulnar border of the radius, the radial styloid, and the midpoint of the ulnar incisura of the radius were the least variable. The palmar and dorsal ends of the ridge delineating the scaphoid and lunate facets were the most variable. Only 1 of the radial inclination measurement methods was clinically acceptable; the others had a repeatability and reproducibility limit of >2°, making those measurements clinically unacceptable.

CONCLUSIONS

The use of isolated points seems insufficient for the development of a wrist reference frame, especially for the purpose of measuring dorsopalmar tilt. If one concurs that an error of 2° is unacceptable for all distal radial measurements, then clinicians should avoid using 3D landmarked points, due to their unreliability, except for radial inclination measured using the radial styloid and the midpoint of the ulnar edge of the radius. A characterization of the wrist using 3D shapes that fit the articular surface of the radius should be considered.

LEVEL OF EVIDENCE

Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Intermediate-Term Outcome of 3-Dimensional Corrective Osteotomy for Malunited Distal Radius Fractures With a Mean Follow-Up of 6 Years

PURPOSE

Our study aimed to analyze the functional and radiological intermediate-term outcome of 3-dimensional-guided corrective osteotomies for malunited distal radius fractures and to evaluate the progression of osteoarthritis after this intervention.

METHODS

All patients with malunited distal radius fractures who underwent 3-dimensional-guided corrective osteotomies from October 2008 to January 2015 were included. Pre- and postoperative range of motion, grip strength, and postoperative patient-reported outcomes were assessed. Pre- and postoperative osteoarthritis grading was performed using conventional radiographs and the osteoarthritis grading system described by Knirk and Jupiter. Additionally, the evaluation of articular stepoff was performed using pre- and postoperative computed tomography.

RESULTS

Fifteen patients, with a mean follow-up of 6 years (range, 4.1-10.4 years), were included. According to rater 1, 8 cases had no postoperative osteoarthritis progression, 6 cases had progression of 1 grade, and 1 case had progression of 2 grades. According to rater 2, there was no progression in 11 cases, and there was progression of 1 grade in 2 cases and progression of 2 grades in 2 cases. Compared with before the surgery, the patients demonstrated a mean improvement of 14.8 kg (±12.6 kg) in grip strength after the surgery. At the last follow-up, the mean Patient-Rated Wrist Evaluation score was 11.8 (±12.0), the mean Disabilities of the Arm, Shoulder and Hand score was 11.1 (±11.4), and the mean residual pain score on the visual analog scale was 0.8 (±1.0).

CONCLUSIONS

The intermediate-term outcome of 3-dimensional-guided corrective osteotomies for distal radius intra-articular malunions showed excellent patient-reported outcomes and no clinically relevant progression of osteoarthritis.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Morphological symmetry of the radius and ulna-Can contralateral forearm bones utilize as a reliable template for the opposite side?

The most important precondition for correction of the affected forearm using data from the contralateral side is that the left and right bone features must be similar, in order to develop patient-specific instruments (PSIs) and/or utilize computer-assisted orthopedic surgery (CAOS). The forearm has complex anatomical structure, and most people use their dominant hand more than their less dominant hand, sometimes resulting in asymmetry of the upper limbs. The aim of this study is to investigate differences of the bilateral forearm bones through a quantitative comparison of whole bone parameters including length, volume, bowing, and twisting parameters, and regional shape differences of the forearm bones. In total, 132 bilateral 3D radii and ulnae 3D models were obtained from CT images, whole bone parameters and regional shape were analyzed. Statistically significant differences in whole bone parameters were not shown. Regionally, the radius shows asymmetry in the upper section of the central part to the upper section of the distal part. The ulna shows asymmetry in the lower section of the proximal part to the lower section of the central part. Utilizing contralateral side forearm bones to correct the affected side may be feasible despite regional differences in the forearm bones of around 0.5 mm.

Exploring partial intrinsic and extrinsic symmetry in 3D medical imaging

We present a novel methodology to detect imperfect bilateral symmetry in CT of human anatomy. In this paper, the structurally symmetric nature of the pelvic bone is explored and is used to provide interventional image augmentation for treatment of unilateral fractures in patients with traumatic injuries. The mathematical basis of our solution is based on the incorporation of attributes and characteristics that satisfy the properties of intrinsic and extrinsic symmetry and are robust to outliers. In the first step, feature points that satisfy intrinsic symmetry are automatically detected in the Möbius space defined on the CT data. These features are then pruned via a two-stage RANSAC to attain correspondences that satisfy also the extrinsic symmetry. Then, a disparity function based on Tukey's biweight robust estimator is introduced and minimized to identify a symmetry plane parametrization that yields maximum contralateral similarity. Finally, a novel regularization term is introduced to enhance similarity between bone density histograms across the partial symmetry plane, relying on the important biological observation that, even if injured, the dislocated bone segments remain within the body. Our extensive evaluations on various cases of common fracture types demonstrate the validity of the novel concepts and the accuracy of the proposed method.

Accuracy and Early Clinical Outcome After 3-Dimensional Correction of Distal Radius Intra-Articular Malunions Using Patient-Specific Instruments

PURPOSE

To investigate the residual articular incongruity on computed tomography image data and the early clinical outcome of 3-dimensional planned and navigated intra-articular osteotomies of the distal radius.

METHODS

We conducted a retrospective analysis of intra-articular osteotomies executed between 2008 and 2016. We identified 37 patients (aged 26-73 years) and performed a combined intra-articular and extra-articular osteotomy on 20 patients. A preoperative 3-dimensional plan with the superimposed bone of the contralateral healthy side was performed in each case to analyze and execute the osteotomy by intraoperative navigation. The residual articular incongruity was assessed by quantification of the maximal stepoff in the coronal or sagittal computed tomography scans. Clinical outcome, including range of motion, grip strength, and return to work, was assessed after a minimum follow-up of 12 months and compared with preoperative measurements.

RESULTS

On average, the preoperative intra-articular stepoff was 2.5 mm (±0.6 mm; range, 1.4-4.2 mm) and was significantly reduced to 0.8 mm (±0.2 mm) after surgery. After surgery, 30 patients had a stepoff less than 1 mm; in 7, a stepoff of 1.1 to 1.4 mm was measured. After 1 year, 22 had no pain, 9 had slight pain during heavy work, and 5 had moderate pain with no improvement compared with their preoperative status, although wrist strength and range of motion improved in all 37 patients. One patient underwent a secondary radioscapholunate arthrodeses owing to persistent pain despite a congruent joint with a small residual intra-articular stepoff (0.6 mm).

CONCLUSIONS

Intra-articular osteotomies of the distal radius treated by 3-dimensional preoperative planning and patient-specific guides are an accurate technique to reduce articular incongruity to an average stepoff of 0.8 mm (range, 0.3-1.4 mm). The early clinical outcomes demonstrated overall reduction in pain and improvement of range of motion and grip strength in 36 of 37 patients.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Three-Dimensional Versus Radiographic Measurements for Analyzing Extra-Articular Distal Radius Malunion

PURPOSE

To compare the accuracy of evaluating deformity in distal radius malunions using plain radiographic measurements compared with a 3-dimensional method involving 3-dimensional computer bone models.

METHODS

Consecutive patients who had an extra-articular distal radius malunion were included. Standard radiographs and computed tomography scans of both wrists were performed. Palmar tilt, radial tilt, and ulnar variance were measured on radiographs. The computed tomography scan data were sent to a workstation and 3-dimensional bone surface models of the radius were created. The 3-dimensional palmar tilt, 3-dimensional radial tilt, 3-dimensional ulnar variance, and axial rotational deformity were calculated.

RESULTS

Thirteen patients, mean age 40 years (range, 22-57 years) were included. The 3 3-dimensional values were positively correlated with their corresponding radiographic values. Nevertheless, the 3-dimesional palmar tilt and 3-dimensional radial tilt values were slightly smaller than the radiographic palmar tilt and radial tilt. The quantitative difference between the 3-dimensional method and plain radiographs was on average 2° for the dorsal deformity group and 3° for the palmar deformity group. The 3-dimensional ulnar variance was significantly higher than the radiographic ulnar variance by an average of +1.3 mm for malunions with dorsal tilt and +0.6 mm for malunions with palmar tilt. The 3-dimensional method allowed us to measure the extent of the axial rotational deformity, which was 9° on average (range, 2° to 21°).

CONCLUSIONS

Despite small differences, measurements made on both plain radiographs and 3-dimensional computer bone models are accurate for evaluating the deformity in extra-articular distal radius malunions. Our 3-dimensional method seems to provide a more accurate measurement of ulnar variance, particularly for dorsally angulated cases, and is helpful for measuring rotational malalignment.

CLINICAL RELEVANCE

In this study, we found that either a 3-dimensional computer bone model or plain radiographs can be used as a benchmark to evaluate the deformity of extra-articular distal radius malunion. The 3-dimensional method can also be used to define axial rotational deformity.

Assessment of grip-motion characteristics in carpal tunnel syndrome patients using a novel finger grip dynamometer system

Background

Grip strength measurement is widely used in daily medical practice, and it has been reported that the grip strength decreases in patients with carpal tunnel syndrome (CTS). However, conventional grip dynamometers evaluate only the maximum power of total grip strength and cannot measure the time course of grip motion. In this report, we aimed to determine the grip characteristics of CTS patients by measuring the time course of each finger’s grip motion and to analyze the relationship between finger grip strength and subjective symptoms using this new grip system.

Methods

The grip strength of each finger was measured using the new grip system that has four pressure sensors on the grip parts of each finger of the Smedley grip dynamometer. We analyzed the time course of grip motion and relationship between finger grip strength and subjective symptoms in 104 volunteer and 51 CTS hands. The Japanese Society for Surgery of the Hand version of the Carpal Tunnel Syndrome Instrument (CTSI-JSSH) and the Disability of Arm, Shoulder, and Hand questionnaire (DASH) were used as subjective evaluation scores.

Results

In the CTS group, the grip time with the index, middle, and ring fingers was longer, and the time at which strength was lost after reaching the maximum was earlier. Patients with severe subjective symptoms tended to not use the index and middle fingers during grip motion.

Conclusions

This new system that measures each finger’s grip strength at one time and record the time course of grip motion could quantify a patient’s symptoms easily and objectively, which may contribute to the evaluation of hand function.