Cubitus varus deformity following paediatric supracondylar humeral fracture remodelling predominantly in the sagittal direction: A three-dimensional analysis of eighty-six cases.

PURPOSE: Three-dimensional (3D) capacity for remodelling in cubitus varus deformity (CVD) after paediatric supracondylar humeral fractures (PSHFs) remains unelucidated. This study investigated remodelling patterns after PSHFs by examining 3D deformity distribution over time after injury. METHODS: Computed tomography (CT) data of 86 patients with CVD after PSHFs were analysed. The 3D deformity angles in the sagittal, coronal, and axial directions were assessed and correlated with the duration between the age at injury and CT evaluation. For the subgroup analysis, we performed the same correlation analysis in a younger (< 8 years old) and an older group (≥ 8 years old); we categorized the duration into early (< 2 years), middle (≥ 2 to < 5 years), and late periods (≥ 5 years) and compared the deformity angles of each direction among the three groups. RESULTS: Sagittal deformity showed a moderate correlation with the duration of deformity (r = -0.54; P < 0.001), while coronal and axial deformities showed a negligible correlation. Sagittal deformity showed moderate correlations with the duration in the younger group (r = -0.62; P < 0.001) and weak correlations in the older group (r = -0.37; P = 0.091). In the sagittal direction, the deformity angle in the early period was significantly larger than those in the mid and late periods (P < 0.001). However, there were no significant differences among the three groups in the coronal and axial directions. CONCLUSION: Sagittal deformities in CVDs are capable of remodelling, especially in the early period and at a younger age, whereas coronal and axial deformities are less likely to undergo remodelling.

Three-dimensional corrective osteotomy for cubitus varus deformity using patient-matched instruments.

Background: Various methods of two or three-dimensional (3D) corrective osteotomy for cubitus varus deformity have been reported. However, whether 3D correction of cubitus varus deformity is necessary is controversial because of technical difficulties and surgical complications. This study introduced 3D simulations and printing technology for corrective osteotomy against cubitus varus deformities. Moreover, recent studies on the application of these technologies were reviewed. Methods: The amount of 3D deformity was calculated based on the difference in 3D shape between the affected side and the contralateral normal side. Patient-matched instruments were created to perform the actual surgery as simulated. Further, a 3D corrective osteotomy was performed using patient-matched instruments for cubitus varus deformity in pediatric and adolescent patients. The humerus-elbow-wrist angle, tilting angle, and elbow ranges of motion were evaluated. Results: Humerus-elbow-wrist angle and tilting angle were corrected from -21° to 14° and from 30° to 43°, respectively, in the pediatric patient and from -18° to 10° and from 20° to 40°, respectively, in the adolescent patient. The elbow flexion and extension angles changed from 130° to 140° and from 20° to 10°, respectively, in the pediatric patient and from 120° to 130° and from 15° to 0°, respectively, in the adolescent patient. Conclusion: The 3D computer simulations and the use of patient-matched instruments for cubitus varus deformity are reliable and can facilitate an accurate and safe correction. These technologies can simplify the complexity of 3D surgical procedures and contribute to the standardization of treatment for cubitus varus deformity.

Reproduction of forearm rotation dynamic using intensity-based biplane 2D-3D registration matching method.

This study aimed to reproduce and analyse the in vivo dynamic rotational motion of the forearm and to clarify forearm motion involvement and the anatomical function of the interosseous membrane (IOM). The dynamic forearm rotational motion of the radius and ulna was analysed in vivo using a novel image-matching method based on fluoroscopic and computed tomography images for intensity-based biplane two-dimensional-three-dimensional registration. Twenty upper limbs from 10 healthy volunteers were included in this study. The mean range of forearm rotation was 150 ± 26° for dominant hands and 151 ± 18° for non-dominant hands, with no significant difference observed between the two. The radius was most proximal to the maximum pronation relative to the ulna, moved distally toward 60% of the rotation range from maximum pronation, and again proximally toward supination. The mean axial translation of the radius relative to the ulna during forearm rotation was 1.8 ± 0.8 and 1.8 ± 0.9 mm for dominant and non-dominant hands, respectively. The lengths of the IOM components, excluding the central band (CB), changed rotation. The transverse CB length was maximal at approximately 50% of the rotation range from maximum pronation. Summarily, this study describes a detailed method for evaluating in vivo dynamic forearm motion and provides valuable insights into forearm kinematics and IOM function.

Acceptable range of forearm deformity derived from relation to three-dimensional analysis and clinical impairments.

This study aimed to investigate deformity patterns that cause clinical impairments and determine the acceptable range of deformity in the treatment of forearm diaphyseal fractures. A three-dimensional (3D) deformity analysis based on computed bone models was performed on 39 patients with malunited diaphyseal both-bone forearm fractures to investigate the 3D deformity patterns of the radius and ulna at the fracture location and the relationship between 3D deformity and clinical impairments. Clinical impairments were evaluated using forearm motion deficit. Cutoff values of forearm deformities were calculated by performing receiver operating characteristic analysis using the deformity angle and the limited forearm rotation range of motion (less than 50° of pronation or supination) resulting in activities of daily living (ADL) impairment as variables. The extension, varus, and pronation deformities most commonly occurred in the radius, whereas the extension deformity was commonly observed in the ulna. A positive correlation was observed between pronation deficit and extension deformity of the radius (R = 0.41) and between supination deficit and pronation deformity of the ulna (R = 0.44). In contrast, a negative correlation was observed between pronation deficit and pronation deformity of the radius (R = -0.44) and between pronation deficit and pronation deformity of the ulna (R = -0.51). To minimize ADL impairment, radial extension deformity should be <18.4°, radial rotation deformity <12.8°, and ulnar rotation deformity <16.6°. The deformities in the sagittal and axial planes of the radius and in the axial plane of the ulna were responsible for the limited forearm rotation.

Neurotropin® accelerates peripheral nerve regeneration in a rat sciatic nerve crush injury model.

BACKGROUND: Peripheral nerve injuries are common and serious conditions. The effect of Neurotropin® (NTP), a nonprotein extract derived from the inflamed skin of rabbits inoculated with vaccinia virus, on peripheral nerve regeneration has not been fully elucidated. However, it has analgesic properties via the activation of descending pain inhibitory systems. Therefore, the current study aimed to determine the effects of NTP on peripheral nerve regeneration. METHODS: We examined axonal outgrowth of dorsal root ganglion (DRG) neurons using immunocytochemistry in vitro. In addition, nerve regeneration was evaluated functionally, electrophysiologically, and histologically in a rat sciatic nerve crush injury model in vivo. Furthermore, gene expression of neurotrophic factors in the injured sciatic nerves and DRGs was evaluated. RESULTS: In the dorsal root ganglion neurons in vitro, NTP promoted axonal outgrowth at a concentration of 10 mNU/mL. Moreover, the systemic administration of NTP contributed to the recovery of motor and sensory function at 2 weeks, and of sensory function, nerve conduction velocity, terminal latency, and axon-remyelination 4 weeks after sciatic nerve injury. In the gene expression assessment, insulin-like growth factor 1 and vascular endothelial growth factor expressions were increased in the injured sciatic nerve 2 days postoperatively. CONCLUSIONS: Therefore, NTP might be effective in not only treating chronic pain but also promoting peripheral nerve regeneration after injury.

Quantitative 3-D CT Demonstrates Distal Row Pronation and Translation and Radiolunate Arthritis in the SNAC Wrist.

BACKGROUND: In scaphoid nonunion advanced collapse (SNAC) wrist arthritis, we analyzed the 3-dimensional (3-D) deformity patterns of carpal alignment secondary to scaphoid nonunion and quantified subchondral arthritis by investigating alterations in bone density. METHODS: We constructed 3-D models of the carpal bones and radius from 51 patients with scaphoid nonunion (nonunion group) and 50 healthy controls (control group). We quantified the differences in 3-D geometric position of the distal carpal row relative to the distal radius in SNAC wrists versus controls. In addition, we assessed the bone density of anatomic regions of interest in the radiocarpal and capitolunate joints relative to the pisiform bone density to characterize degenerative changes in SNAC wrists. RESULTS: The distal carpal row pronated by a difference of 14° (7.2° versus -6.7°; p < 0.001), deviated ulnarly by a difference of 19° (7.7° versus -11.2°; p < 0.001), shifted dorsally by a difference of 17% of the dorsovolar width of the distal radius (21.0% versus 4.4%; p < 0.001), shifted radially by a difference of 8% of the radioulnar width of the distal radius (13.2% versus 5.3%; p < 0.001), and migrated proximally by a difference of 12% of the lunate height (96.3% versus 108.8%; p < 0.001) in the nonunion group compared with the control group. Additionally, it was found that bone density was greater at the capitolunate joint (capitate head: 140.4% versus 123.7%; p < 0.001; distal lunate: 159.9% versus 146.3%; p < 0.001), the radial styloid (157.0% versus 136.3%; p < 0.001), and the radiolunate joint (proximal lunate: 134.8% versus 122.7%; p < 0.001; lunate fossa: 158.6% versus 148.1%; p = 0.005) in the nonunion group compared with the control group. CONCLUSIONS: Scaphoid nonunion exhibited a unique deformity pattern and alteration in bone-density distributions. The distal carpal row not only shifted dorsally and migrated proximally but also pronated, deviated ulnarly, and shifted radially. Bone density was greater at the capitolunate joint, the radial styloid, and surprisingly, the radiolunate joint. Our findings give insight into the natural history and progression of arthritis of the SNAC wrist. Additionally, future studies may give insight into whether successful treatment of scaphoid nonunion arrests the progression of arthritis. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Artificial intelligence to diagnosis distal radius fracture using biplane plain X-rays.

BACKGROUND: Although the automatic diagnosis of fractures using artificial intelligence (AI) has recently been reported to be more accurate than those by orthopedics specialists, big data with at least 1000 images or more are required for deep learning of the convolutional neural network (CNN) to improve diagnostic accuracy. The aim of this study was to develop an AI system capable of diagnosing distal radius fractures with high accuracy even when learning with relatively small data by learning to use bi-planar X-rays images. METHODS: VGG16, a learned image recognition model, was used as the CNN. It was modified into a network with two output layers to identify the fractures in plain X-ray images. We augmented 369 plain X-ray anteroposterior images and 360 lateral images of distal radius fractures, as well as 129 anteroposterior images and 125 lateral images of normal wrists to conduct training and diagnostic tests. Similarly, diagnostic tests for fractures of the styloid process of the ulna were conducted using 189 plain X-ray anteroposterior images of fractures and 302 images of the normal styloid process. The distal radius fracture is determined by entering an anteroposterior image of the wrist for testing into the trained AI. If it identifies a fracture, it is diagnosed as the same. However, if the anteroposterior image is determined as normal, the lateral image of the same patient is entered. If a fracture is identified, the final diagnosis is fracture; if the lateral image is identified as normal, the final diagnosis is normal. RESULTS: The diagnostic accuracy of distal radius fractures and fractures of the styloid process of the ulna were 98.0 ± 1.6% and 91.1 ± 2.5%, respectively. The areas under the receiver operating characteristic curve were 0.991 {n = 540; 95% confidence interval (CI), 0.984-0.999} and 0.956 (n = 450; 95% CI 0.938-0.973). CONCLUSIONS: Our method resulted in a good diagnostic rate, even when using a relatively small amount of data.

2D-3D reconstruction of distal forearm bone from actual X-ray images of the wrist using convolutional neural networks.

The purpose of the study was to develop a deep learning network for estimating and constructing highly accurate 3D bone models directly from actual X-ray images and to verify its accuracy. The data used were 173 computed tomography (CT) images and 105 actual X-ray images of a healthy wrist joint. To compensate for the small size of the dataset, digitally reconstructed radiography (DRR) images generated from CT were used as training data instead of actual X-ray images. The DRR-like images were generated from actual X-ray images in the test and adapted to the network, and high-accuracy estimation of a 3D bone model from a small data set was possible. The 3D shape of the radius and ulna were estimated from actual X-ray images with accuracies of 1.05 ± 0.36 and 1.45 ± 0.41 mm, respectively.

Computer-Aided Assessment of Displacement and Reduction of Distal Radius Fractures.

This study aims to investigate displacements and reductions of distal radius fractures using measurement indices based on the computer-aided three-dimensional (3D) radius shape model. Fifty-two distal radius fracture patients who underwent osteosynthesis were evaluated with pre- and post-operative distal radius 3D images. In the 3D images, three reference points, i.e., the radial styloid process (1), sigmoid notch volar, and dorsal edge (2) (3) were marked. The three-dimensional coordinates of each reference point and the barycentric coordinates of the plane connecting the three reference points were evaluated. The distance and direction moved, due to the reductions for each reference point, were (1) 12.1 ± 8.1 mm in the ulnar-palmar-distal direction, (2) 7.5 ± 4.1 mm in the ulnar-palmar-proximal direction, and (3) 8.2 ± 4.7 mm in the ulnar-palmar-distal direction relative to the preoperative position. The barycentric coordinate moved 8.4 ± 5.3 mm in the ulnar-palmar-distal direction compared to the preoperative position. This analyzing method will be helpful to understand the three-dimensional direction and the extent of displacements in distal radius fractures.

Three-dimensional evaluations of preoperative planning reproducibility for the osteosynthesis of distal radius fractures.

BACKGROUND: Three-dimensional preoperative planning was applied for the osteosynthesis of distal radius fractures. The objective of this study was to evaluate the reproducibility of three-dimensional preoperative planning for the osteosynthesis of distal radius fractures with three-dimensional reference points. METHODS: Sixty-three wrists of 63 distal radius fracture patients who underwent osteosynthesis with three-dimensional preoperative planning were evaluated. After taking preoperative CT scans of the injured wrists, 3D images of the distal radius were created. Fracture reduction, implants choices, and placements simulation were performed based on the 3D images. One month after the surgery, postoperative CT images were taken. The reproducibility was evaluated with preoperative plan and postoperative 3D images. The images were compared with the three-dimensional coordinates of radial styloid process, volar and dorsal edges of sigmoid notch, and the barycentric coordinates of the three reference points. The reproducibility of the preoperative plan was evaluated by the distance of the coordinates between the plan and postoperative images for the reference points. The reproducibility of radial inclination and volar tilt on three-dimensional images were evaluated by intra-class correlation coefficient (ICC). RESULTS: The distances between the preoperative plan and the postoperative reduction for each reference point were (1) 2.1±1.3 mm, (2) 1.9±1.2 mm, and (3) 1.9±1.2 mm, respectively. The distance between the preoperative plan and postoperative reduction for the barycentric coordinate was 1.3±0.8 mm. ICCs were 0.54 and 0.54 for the volar tilt and radial inclination, respectively (P<0.01). CONCLUSIONS: Three-dimensional preoperative planning for the osteosynthesis of distal radius fracture was reproducible with an error of about 2 mm for each reference point and the correlations of reduction shapes were moderate. The analysis method and reference points may be helpful to understand the accuracy of reductions for the three-dimensional preoperative planning in the osteosynthesis of distal radius fractures. TRIAL REGISTRATION: Registered as NCT02909647 at ClinicalTrials.gov.

Utility of a 3-dimensionally printed color-coded bone model to visualize impinging osteophytes for arthroscopic débridement arthroplasty in elbow osteoarthritis.

BACKGROUND: The identification and precise removal of bony impingement lesions during arthroscopic débridement arthroplasty for elbow osteoarthritis require a high level of experience and surgical skill. We have developed a new technique to identify impinging osteophytes on a computer display by simulating elbow motion using the multiple positions of 3-dimensional (3D) elbow models created from computed tomography data. Moreover, an actual color-coded 3D model indicating the impinging osteophytes was created with a 3D printer and was used as an intraoperative reference tool. This study aimed to verify the efficacy of these new technologies in arthroscopic débridement for elbow osteoarthritis. METHODS: We retrospectively studied 16 patients treated with arthroscopic débridement for elbow osteoarthritis after a preoperative computer simulation. Patients who underwent surgery with only the preoperative simulation were assigned to group 1 (n = 8), whereas those on whom we operated using a color-coded 3D bone model created from the preoperative simulation were assigned to group 2 (n = 8). Elbow extension and flexion range of motion (ROM), the Mayo Elbow Performance Score (MEPS), and the severity of osteoarthritis were compared between the groups. RESULTS: Although preoperative elbow flexion and MEPS values were not significantly different between the groups, preoperative extension was significantly more restricted in group 2 than in group 1 (P = .0131). Group 2 tended to include more severe cases according to the Hastings-Rettig classification (P = .0693). ROM and MEPS values were improved in all cases. No significant differences in postoperative ROM or MEPS values were observed between the groups. There were no significant differences in the improvement in ROM or MEPS values between the 2 groups. CONCLUSIONS: The use of preoperative simulation and a color-coded bone model could help to achieve as good postoperative ROM and MEPS values for advanced elbow osteoarthritis as those for early and intermediate stages.

Arthroscopic Debridement of Elbow Osteoarthritis Using CT-Based Computer-Aided Navigation Systems Is Accurate.

PURPOSE: To evaluate whether the bony impingement lesion in elbow osteoarthritis can be removed accurately, as planned during arthroscopy, by using the computer-aided navigation system and performing mock surgery using 3-dimensional (3D)-printed bone models for clinical applications. METHODS: We performed mock surgery using 3D-printed plaster bone models of the humerus of 15 actual patients with elbow osteoarthritis. Two types of experiments were conducted to evaluate the surgical accuracy. Three surgeons performed the mock surgery, each with 15 bone models (total, 45 trials). Surgical accuracy was based on the mean of 45 trials. The differences in surgical accuracy among the 3 surgeons were also evaluated (mean 15 trials). The same surgeon performed 30 trials, and the difference in surgical accuracy between the first and the second halves was also evaluated (mean 15 trials). RESULTS: The spatial error in the entire elbow joint was 1.13 mm. In terms of resection volume, a mean of 8% more volume was resected than was planned, and 85% of the planned area was resected. In our experiments, the surgical accuracy was significantly lower in the anterior than in the posterior joint. Intrarater reliability was intraclass correlation (ICC)2,1 0.81 and inter-rater reliability was ICC1,1 0.87. CONCLUSIONS: Surgery using computer-aided navigation systems for arthroscopic debridement of the elbow provided accuracy comparable to that in other joints. CLINICAL RELEVANCE: Arthroscopic debridement of elbow osteoarthritis requires advanced surgical skills because accurate identification of the bony impingement legion is difficult during surgery. Surgery using computer-aided navigation systems for arthroscopic debridement of the elbow will provide real-time tracking of both the surgical instruments and bony impingement lesions as well as solve the technical difficulties of arthroscopic surgery of the elbow joint.

Degenerative changes in the elbow joint after radial head excision for fracture: quantitative 3-dimensional analysis of bone density, stress distribution, and bone morphology.

HYPOTHESIS AND BACKGROUND: Some investigators speculate that excision may lead to elbow arthritis and associated problems; however, evidence supporting this theory is limited. It is hypothesized that radial head excision causes bone density changes as a result of asymmetrical stress distributions, consequently leading to osteophyte formation. In this study, we sought to quantitatively compare the 3-dimensional (3D) bone density and stress distributions between operative and nonoperative elbows in patients who underwent radial head excision. Furthermore, we aimed to quantify the bone morphologic changes using 3D models in the same cohort. METHODS: After retrospective identification, this study enrolled 6 patients who had undergone radial head excision for radial head fractures. We created 3D bone models using computed tomography data obtained from the injured and uninjured elbows. Humerus and ulna models were divided into anatomic regions, and the bone density of each region was assessed and described by its percentage of high-density volume (%HDV). We also constructed finite element models and measured the stress values in each region. Furthermore, we compared the bone morphology by superimposing the operative elbow onto the mirror image of the nonoperative elbow. RESULTS: The mean interval from radial head excision to examination was 8.4 ± 3.3 years. The %HDV on the operative side was higher than that of the nonoperative side at the anterolateral trochlea (77.5% ± 6.5% vs. 64.6% ± 4.0%, P = .028) and posterolateral trochlea (70.7% ± 7.8% vs. 63.1% ± 3.8%, P = .034) regions of the distal humerus. Reciprocal changes were observed in the proximal ulna, as %HDV was higher in the lateral coronoid (52.6% ± 9.6% vs. 34.2% ± 6.6%, P = .007). The stress distributions paralleled the bone density measurements. The operative elbows demonstrated an enlarged capitellum and a widened and deepened trochlea with osteophyte formation compared with the nonoperative side. DISCUSSION AND CONCLUSION: In elbows treated with radial head excision, we identified asymmetrical bone density and stress alterations on the lateral side of the ulnohumeral joint and bone morphologic changes across the joint. These data support the theory that radial head excision contributes to ulnohumeral arthritis over the long term.

Quantitative Analysis for the Change in Lengths of the Radius and Ulna in Missed Bado Type I Monteggia Fracture.

BACKGROUND: In missed Monteggia fracture (MMF) cases, ulnar angulation and lengthening by osteotomy are required to reduce the dislocated radial head. This study aimed to clarify the abnormal discrepancy in length between the radius and ulna in MMF. We tested the hypothesis that the increase in the abnormal discrepancy in length between the radius and ulna relates with the duration of radial head dislocation. METHODS: In total, 24 patients with MMF were studied and classified into 2 groups, according to the duration of radial head dislocation, including the early group (n=9, within 3 y) and the long-standing group (n=15, older than 3 y). The lengths of the radius (Lr) and ulna (Lu) were measured. The difference in length between the ulna and radius (DL=Lu-Lr) was calculated on both the affected (DLaff) and normal (DLnor) sides. DLnor-DLaff, which represented an abnormal discrepancy in both bones, was analyzed for correlation with the duration of radial head dislocation and the age at initial injury. RESULTS: The affected and normal sides had no differences in the Lr of both the groups and in the Lu of the early group. However, in the long-standing group, Lu was significantly smaller in the affected side than in the normal side (P=0.001). In the long-standing group, DLaff was significantly smaller, owing to decreased length of the ulna, than DLnor (P=0.003). The DLnor-DLaff was positively correlated with the duration of radial head dislocation and was negatively correlated with the age at injury. CONCLUSIONS: In chronic MMF cases, the length of the ulna was shorter in the affected side than in the normal side. Therefore, ulnar lengthening is necessary to resolve this abnormal discrepancy and reduce the radial head. Because excessive ulnar lengthening has risks of postoperative complications, one of the surgical options is gradual ulnar lengthening or shortening osteotomy of the radius. LEVEL OF EVIDENCE: Level III-Prognosis study.

Utility of Distal Forearm DXA as a Screening Tool for Primary Osteoporotic Fragility Fractures of the Distal Radius: A Case-Control Study.

BACKGROUND: Osteoporotic fragility fractures frequently occur at the distal part of the radius. This suggests that initial osteoporosis evaluation at this site may inform screening and treatment to prevent additional fractures. The purpose of this study was to investigate the utility of distal forearm dual x-ray absorptiometry (DXA) as a screening tool to assess the risk of fragility fractures at the distal part of the radius. METHODS: This retrospective, case-control study included postmenopausal women who had sustained a distal radial fracture (fracture group, n = 110) and postmenopausal women with no history of fracture (control group, n = 95). DXA measurements at the spine, hip, and distal part of the forearm (ultra-distal, mid-distal, and one-third distal sections) were compared between the groups on the basis of bone mineral density (BMD), T-score, and the proportion of patients with a T-score of ≤-2.5 standard deviations (SD). We also investigated the regional differences on the basis of T-score among the skeletal sites. Furthermore, the reliability of distal forearm DXA measurements was validated by assessing the statistical correlation (r) with volumetric BMD by computed tomography (CT). RESULTS: Compared with the control group, the fracture group showed significantly lower BMD and T-scores and higher proportions of patients with a T-score of ≤-2.5 SD at the ultra-distal, mid-distal, and one-third distal forearm; however, the spine and hip measurements did not differ significantly between the 2 groups. With respect to regional differences, in the fracture group, T-scores were significantly lower and the proportions of patients with a T-score of ≤-2.5 SD were significantly higher for the 3 distal forearm sites compared with the spine and hip. DXA measurements at all 3 of the distal forearm regions exhibited high correlation with volumetric BMD by CT (r = 0.83 to 0.92). CONCLUSIONS: Some postmenopausal women were found to exhibit bone loss preferentially at the distal part of the radius, which may render them vulnerable to fragility fractures. Forearm DXA for the assessment of local bone loss may demonstrate benefit in screening for those at risk for distal radial fractures and facilitate the early identification of patients who require intervention for osteoporosis. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Three-dimensional analysis of displacement characteristics of dorsally angulated intra-articular distal radial fractures.

Understanding the complex fragmentation of intra-articular distal radial fractures contributes to achieving anatomical reduction during surgery. This study aimed to clarify three-dimensional displacement patterns of intra-articular fragmentation in dorsally angulated, intra-articular distal radial fractures. We identified five characteristic intra-articular fragments: a key fragment, dorsal ulnar corner, dorsal wall, radial column and anterior radial column. The key fragment was displaced with radial deviation, pronation and extension and with dorsal, proximal and radial translations. The dorsal ulnar corner displacement resulted in a gap, a step-off and a deepened concavity for the lunate facet and sigmoid notch. The dorsal wall displacement resulted in a deepened concavity, a gap and a step-off of the dorsal scaphoid facet. The displacements of the radial column and anterior radial column caused a step-off between the scaphoid and lunate facets. The five characteristic intra-articular fragments each created a characteristic gap and step-off in the articular surface. Level of evidence: IV.

Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using three-dimensional surgical computer simulation and patient-matched instrument.

BACKGROUND: Corrective osteotomy of malunited intra-articular distal radius fracture is challenging. In this study, we investigated the results in patients with malunited intra-articular distal radius fracture who underwent intra-articular corrective osteotomy through an extra-articular approach using three-dimensional (3-D) computer simulation and a patient-matched instrument (PMI). METHODS: We retrospectively studied five consecutive patients with symptomatic malunited intra-articular distal radius fracture who underwent corrective osteotomy using a PMI. The maximal step-off on computed tomography and the deformity angle on plain radiographs were evaluated. The clinical examination parameters included range of motion (ROM), grip strength, pain according to visual analog scale (VAS), and Patient-Rated Wrist Evaluation (PRWE) score. RESULTS: The maximal step-off was significantly reduced from 4.9 ± 1.8 to 1.0 ± 0.2 mm (p = 0.008). The absolute differences between the affected side and the normal contralateral side in radial inclination were significantly reduced from 5.4° ± 3.4°-1.2° ± 1.1° (p = 0.043). These differences were not significantly reduced postoperatively in the volar tilt and ulnar variance. VAS was significantly reduced from 4.1 ± 1.6 to 0.9 ± 0.7 cm (p = 0.006). The PRWE score significantly improved from 41.6 ± 22.0 to 15.7 ± 19.5 (p = 0.043). Grip strength was significantly increased from 54.0% ± 14.8%-85.8% ± 18.8% (p = 0.003). The preoperative and postoperative total arc of the wrist and forearm ROM were not significantly different. CONCLUSIONS: Intra-articular corrective osteotomy using PMI could be one of the reliable treatment options for intra-articular malunion. PMI has exceptionally high precision performance, and it is also anticipated to yield superior surgical results.

Combination of Electrospun Nanofiber Sheet Incorporating Methylcobalamin and PGA-Collagen Tube for Treatment of a Sciatic Nerve Defect in a Rat Model.

BACKGROUND: For peripheral nerve defects, autografting is considered the therapeutic gold-standard treatment. However, this procedure leads to donor-site morbidity. While various artificial conduits have been recently developed, treatment outcome has been demonstrated to be poorer than that with autograft. In our previous study using a rat sciatic nerve crush injury model, we demonstrated that the delivery of electrospun nanofiber sheets incorporating methylcobalamin (MeCbl sheet) to the local site of a peripheral nerve injury promoted peripheral nerve regeneration. In this study, we examined the effects of combination therapy using an MeCbl sheet and a polyglycolic acid tube filled with collagen sponge (PGA-c) in a rat model of a 10-mm sciatic nerve defect. METHODS: The rats were divided into 4 groups: (1) sham group (n = 10); (2) PGA-c group (n = 9), in which the gap was bridged using a PGA-c; (3) PGA-c/Sheet group (n = 8), in which the gap was bridged using a PGA-c wrapped in an MeCbl sheet; and (4) autograft group (n = 10), in which the gap was bridged using a reversed autograft. Motor and sensory function were evaluated, electrophysiological analysis was performed, and histomorphological findings were analyzed at 12 weeks postoperatively. RESULTS: Compared with the PGA-c group, the PGA-c/Sheet group demonstrated significant improvements in the paw-withdrawal threshold expressed as a ratio relative to the contralateral side (mean difference [MD], -1.51; 95% confidence interval [CI], -2.64 to -0.38), terminal latency (MD, -0.86 ms; 95% CI, -1.56 to -0.16 ms), myelinated axon area (MD, 4.97%; 95% CI, 0.14% to 9.80%), proportion of myelinated axons (MD, 8.453%; 95% CI, 0.001% to 16.905%), and g-ratio (MD, -0.018; 95% CI, -0.035 to -0.001). No significant improvements were observed regarding motor function, electrophysiological findings with the exception of terminal latency, and axon numbers. CONCLUSIONS: An MeCbl sheet in combination with a PGA-c significantly accelerated recovery with respect to sensory function, electrophysiology, and histomorphometry. CLINICAL RELEVANCE: An MeCbl sheet may represent an effective therapeutic strategy for promoting regeneration across a nerve gap bridged with an artificial conduit.

Regional Distribution of Articular Cartilage Thickness in the Elbow Joint: A 3-Dimensional Study in Elderly Humans.

During elbow procedures, reconstruction of the joint (including the articular cartilage) is important in order to restore elbow function; however, the regional distribution of elbow cartilage is not completely understood. The purpose of the present study was to investigate the 3-dimensional (3-D) distribution patterns of cartilage thickness of elbow bones (including the distal part of the humerus, proximal part of the ulna, and radial head) in order to elucidate the morphological relationship among them. METHODS: Two 3-D surface models were created with use of a laser scanner: (1) a cartilage-bone model based on 20 elderly cadaveric elbows exhibiting normal cartilaginous conditions and (2) a bone model that was created after dissolving the cartilage. The 2 models were superimposed, and cartilage thickness was measured as the interval distance on the articular surface. Measurements were made at categorized anatomical points of the individual bones, and 3-D distributions on the entire articular surface were analyzed. The spatial relationship among individual bones was also assessed. RESULTS: In the distal part of the humerus, the cartilage was thickest in the intermediate region between the capitellum and the trochlea (mean [and standard deviation], 1.27 ± 0.17 mm); in the proximal part of the ulna, it was thickest at the anterolateral edge of the coronoid (2.20 ± 0.39 mm) and the anteroproximal edge of the proximal sigmoid notch (2.49 ± 0.55 mm); and in the radial head, it was thickest at the articular zone on the rim circumference within the dish (1.10 ± 0.17 mm) and on the proximal circumference around the side (1.02 ± 0.17 mm) (p < 0.001 for all). These thicker cartilage regions gathered on the joint center, facing each other. CONCLUSIONS: The present study demonstrated regional variations in elbow cartilage thickness. The combined findings in individual bones showed "cartilage gathering" at the center of the elbow joint, which we believe to be a novel anatomical finding. CLINICAL RELEVANCE: An enhanced understanding of elbow cartilage geometry will provide additional insights into elbow procedures in elderly individuals, such as hemiarthroplasties, in which anatomical contours could help to restore normal joint function and improve postoperative outcomes.

Validation of the registration accuracy of navigation-assisted arthroscopic débridement for elbow osteoarthritis.

BACKGROUND: The identification and precise removal of bony impingement lesions during arthroscopic débridement arthroplasty for elbow osteoarthritis is technically difficult. Surgical navigation systems, combined with preoperative 3-dimensional (3D) assessment of bony impingements, can provide real-time tracking of the surgical instruments and impingement lesions. This study aims to determine the registration accuracy of the navigation system for the humerus and ulna during elbow arthroscopy. METHODS: We tested the registration procedure using resin bone models of 3 actual patients with elbow osteoarthritis. We digitized bone surface points using navigation pointers under arthroscopy. We initially performed paired-point registration, digitizing 6 preset anatomical landmarks, and then refined the initial alignment with surface matching registration, digitizing 30 points. The registration accuracy for each trial was evaluated as the mean target registration error in each reference marker. Three observers repeated the registration procedure 5 times each with the 3 specimens (total, 45 trials). The median of the registration accuracy was evaluated in total (45 trials) as the accuracy of the registration procedure. The differences in the registration accuracy among the 3 observers (median of 15 trials) were also examined. RESULTS: The total registration accuracies were 0.96 mm for the humerus and 0.85 mm for the ulna. No significant differences were found in the registration accuracy for the humerus and ulna among the 3 observers. CONCLUSIONS: This arthroscopic-assisted registration procedure is sufficiently feasible and accurate for application of the navigation system to arthroscopic débridement arthroplasty in clinical settings.