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.

The effect of forearm rotation on the bone mineral density measurements of the distal radius.

INTRODUCTION: Forearm dual-energy X-ray absorptiometry (DXA) is often performed in clinics where central DXA is unavailable. Accurate bone mineral density (BMD) measurement is crucial for clinical assessment. Forearm rotation can affect BMD measurements, but this effect remains uncertain. Thus, we aimed to conduct a simulation study using CT images to clarify the effect of forearm rotation on BMD measurements. MATERIALS AND METHODS: Forearm CT images of 60 women were analyzed. BMD was measured at the total, ultra-distal (UD), mid-distal (MD), and distal 33% radius regions with the radius located at the neutral position using digitally reconstructed radiographs generated from CT images. Then, the rotation was altered from - 30° to 30° (supination set as positive) with a one-degree increment, and the percent BMD changes from the neutral position were quantified for all regions at each angle for each patient. RESULTS: The maximum mean BMD changes were 5.8%, 7.0%, 6.2%, and 7.2% for the total, UD, MD, and distal 33% radius regions, respectively. The analysis of the absolute values of the percent BMD changes from the neutral position showed that BMD changes of all patients remained within 2% when the rotation was between - 5° and 7° for the total region, between - 3° and 2° for the UD region, between - 4° and 3° for the MD region, and between - 3° and 1° for the distal 33% radius region. CONCLUSION: Subtle rotational changes affected the BMD measurement of each region. The results showed the importance of forearm positioning when measuring the distal radius BMD.

Study of Reliability and Validity of the Load Cell-Type Hand Dynamometer Compared to the Jamar Dynamometer and the Number of Reliable Grip Strength Measurements.

Background: Standardised measurement protocols for grip strength remained unclear due to variations in values depending on the device and measurement method. The load cell hand dynamometer has recently been developed. This study aims to investigate the reliability of the load cell dynamometer by comparing it to the Jamar dynamometer, which is considered the gold standard, and to identify a reliable and practical measurement method. Methods: This study included 80 healthy hospital workers (mean age of 40.1 years). All measurements were performed seated, with the elbow flexed 90° and the grip span at the second handle (approximately 50 mm) for the Jamar dynamometer, and with the elbow extended and the grip span fixed at 55 mm for the load cell dynamometer. Grip strength was measured three times on each hand using two dynamometers, and the same tests were repeated on different days. Test-retest reliability, the association between the two devices and the agreement between the two measurement methods were assessed using the intraclass correlation coefficient (ICC), Pearson correlation and the Bland-Altman analysis. Results: The ICC of the one measurement was lower than that of three measurements for both dynamometers, but was above 0.858 in all groups, indicating sufficient reliability with one-time measurement. Additionally, the ICC for different days revealed good reliability (Jamar: >0.830, load cell: >0.772). The load cell dynamometer showed significantly lower values in all measurements despite the excellent correlation (r > 0.70) and the agreement between the two dynamometers. Conclusions: This study revealed sufficient reliability of the load cell dynamometer with the standardised measurement method, but it should be noted the lower values compared to the Jamar dynamometer. Additionally, one-time measurement reliability is adequate for practical use by standardising the measurement methods for both dynamometers. Level of Evidence: Level III (Diagnostic).

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.

A Quantitative Analysis of Subchondral Bone Density Around Osteochondritis Dissecans Lesions of the Capitellum.

PURPOSE: In capitellar osteochondritis dissecans (OCD), unstable lesions generally demonstrate signs of subchondral sclerosis. We postulate that OCD lesions have abnormal subchondral bone density. We aimed to quantify the subchondral bone thickness around OCD lesions using conventional computed tomography (CT) imaging. METHODS: This retrospective study included 15 patients with capitellar OCD (OCD group) and 12 patients with an unaffected radio-capitellar joint (control group). We constructed 3-dimensional humerus models using CT data and quantified the bone density with colored contour mapping to determine the subchondral bone thickness. We measured the thickness relative to the condylar height at the centroid and lateral, medial, superior, and inferior edge points of the OCD lesion, and compared the findings between the groups. We then correlated the CT measurements with the magnetic resonance imaging measurements. RESULTS: Subchondral bone thickness at the centroid and lateral, medial, superior, and inferior edges in the OCD group was significantly higher than that in the control group. Correlation analyses revealed that the magnetic resonance imaging measurements highly correlated with the CT subchondral bone measurements. CONCLUSIONS: We found that there is a zone of increased subchondral bone thickness around OCD lesions that should be considered during drilling, microfracture, or other reconstruction methods. We observed a high correlation with low errors between the measurements taken from conventional CT images and the measurements from magnetic resonance imaging, suggesting that both modalities are useful in clinical decision making. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.

Comparison of the Orientation Angles of Volar Locking Plate Distal Ulnar Locking Screw for Distal Radius Fractures.

PURPOSE: This study aimed to measure the angles between the screw and plate in 16 commercially available volar locking plates (VLPs) to determine the fixable intra-articular fragment size. METHODS: Ulnar orientation angles (axial plane) and elevation angles (sagittal plane) between the distal ulnar screw and plate were measured for 14 fixed-angle VLPs and 2 variable-angle VLPs. Each VLP was simulated by 2 surgeons to sit distally and ulnarly in 10 normal distal radius models. The distance between the screw and distal/ulnar end of the distal radius on both the volar and dorsal sides, designated as the longitudinal/lateral distance, was measured to identify the fixable size of the 2 intra-articular fragments: volar lunate fragment and dorsoulnar fragment. Relationships between the ulnar orientation angle and dorsal-side lateral length as well as the elevation angle and dorsal-side longitudinal distance were analyzed. RESULTS: The ulnar orientation and elevation angles ranged from 6.5° to 16.9° and -5.8° to 34.3°, respectively, for fixed-angle VLPs and -12.5° to 32.2° and 3.1° to 42.1°, respectively, for variable-angle VLPs. The minimal longitudinal distances on the volar side with the fixed- and variable-angle VLPs were 4.3-10.9 mm and 5.8-5.9 mm, respectively. On the dorsal side, the lateral distance negatively correlated with the ulnar orientation angle (R = -0.74), and the longitudinal distance negatively correlated with the elevation angle (R = -0.89). CONCLUSIONS: The Depuy Synthes variable-angle VLP provides an advantage for fixating small intra-articular fragments. For fixed-angle VLPs, the Mizuho VLP provides an advantage for fixating small volar lunate fragments. A narrow dorsoulnar fragment can be fixated using a plate with a large ulnar orientation angle, such as the Zimmer Biomet or Mizuho VLP. CLINICAL RELEVANCE: The ability of each individual commercially available plate to capture specific intra-articular fragments should be known.

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.

Comparing the locking screw direction of three locking plates for lateral clavicle fractures: a simulation study.

BACKGROUND: The locking plate is a useful treatment for lateral clavicle fractures, however, there are limits to the fragment size that can be fixed. The current study aimed to measure the screw angles of three locking plates for lateral clavicle fractures. In addition, to assess the number of screws that can be inserted in different fragment sizes, to elucidate the size limits for locking plate fixation. METHODS: The following three locking plates were analyzed: the distal clavicle plate [Acumed, LLC, Oregon, the USA], the LCP clavicle plate lateral extension [Depuy Synthes, LLC, PA, the USA], and the HAI clavicle plate [HOMS Engineering, Inc., Nagano, Japan]. We measured the angles between the most medial and lateral locking screws in the coronal plane and between the most anterior and posterior locking screws in the sagittal plane. A computer simulation was used to position the plates as laterally as possible in ten normal three-dimensional clavicle models. Lateral fragment sizes of 10, 15, 20, 25, and 30 mm were simulated in the acromioclavicular joint, and the number of screws that could be inserted in the lateral fragment was assessed. Subsequently, the area covered by the locking screws on the inferior surface of the clavicle was measured. RESULTS: The distal clavicle plate had relatively large screw angles (20° in the coronal plane and 32° in the sagittal plane). The LCP clavicle lateral extension had a large angle (38°) in the sagittal plane. However, the maximum angle of the HAI clavicle plate was 13° in either plane. The distal clavicle plate allowed most screws to be inserted in each size of bone fragment. For all locking plates, all screws could be inserted in 25 mm fragments. The screws of distal clavicle plate covered the largest area on the inferior surface of the clavicle. CONCLUSIONS: Screw angles and the numbers of screws that could be inserted in the lateral fragment differed among products. Other augmented fixation procedures should be considered for fractures with fragment sizes < 25 mm that cannot be fixed with a sufficient number of screws.

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.

A Three-Step Method for the Treatment of Radioulnar Synostosis with Posterior Radial Head Dislocation.

Congenital radioulnar synostosis with posterior dislocation of the radial head remains challenging to treat. We describe a three-step treatment method that combines radial shaft osteotomy with a custom-made device, ulnar shaft osteotomy, and local adipofascial flap elevation procedures. For posterior radial head dislocation treatment, osteotomy near the proximal radius cannot recover physiological rotation of the radial head. Thus, we chose a precise radial shaft osteotomy with a custom-made device according to preoperative planning based on three-dimensional evaluation of the bone deformation. Performing radial shaft osteotomy alone, however, may not be enough to achieve sufficient supination range of motion. We, therefore, also performed ulnar shaft osteotomy. Finally, we elevated the local adipofascial flap to prevent re-adhesion. In three patients, the range of motion of the elbow improved postoperatively. In conclusion, our three-step method does not require a microsurgical technique and is easy to perform.

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.

Bone resorption of the greater tuberosity after open reduction and internal fixation of complex proximal humeral fractures: fragment characteristics and intraoperative risk factors.

HYPOTHESIS AND BACKGROUND: In complex proximal humeral fractures, bone resorption of the greater tuberosity is sometimes observed after open reduction and internal fixation (ORIF). However, this has not been well characterized, and risk factors for resorption are not completely understood. We aimed (1) to identify the risk factors associated with bone resorption of the greater tuberosity and (2) to quantify the geometric and bone density characteristics associated with bone resorption using 3-dimensional computed tomography models in complex proximal humeral fractures treated with ORIF. METHODS: We identified a retrospective cohort of 136 patients who underwent ORIF of 3- or 4-part proximal humeral fractures; greater tuberosity resorption developed after ORIF in 30 of these patients. We collected demographic, fracture-related, and surgery-related characteristics and performed multivariable logistic regression analysis to identify factors independently associated with the development of greater tuberosity resorption. Furthermore, we identified 30 age- and sex-matched patients by use of propensity score matching to perform quantitative fragment-specific analysis using 3-dimensional computed tomography models. After the fragment of the greater tuberosity was identified, the number of fragments, the relative fragment volume to the humeral head, and the relative bone density to the coracoid process were calculated. Measurements were compared between matched case-control groups. RESULTS: We found that an unreduced greater tuberosity (odds ratio [OR], 10.9; P < .001), inadequate medial support at the calcar (OR, 15.0; P < .001), and the use of an intramedullary fibular strut (OR, 4.5; P = .018) were independently associated with a higher risk of bone resorption. Quantitative fragment-specific analysis showed that greater tuberosities with a larger number of fragments (5 ± 2 vs. 3 ± 2, P = .021), smaller fragments (9.9% ± 3.8% vs. 18.6% ± 4.7%, P < .001), and fragments with a lower bone density (66.4% ± 14.3% vs. 88.0% ± 18.4%, P = .001) had higher rates of resorption. DISCUSSION AND CONCLUSION: An unreduced greater tuberosity or inadequate medial support increases the risk of greater tuberosity resorption, as do a larger number of fracture fragments, smaller fragments, and lower bone density. Additionally, fibular strut grafting is an independent risk factor for tuberosity resorption. Further study is needed, but alternatives to strut grafting such as femoral head allograft may warrant serious consideration.

Parallel plate fixation for distal humeral fracture: Computer simulation to determine the appropriate screw insertion sequence.

BACKGROUND: Parallel plate fixation for distal humeral fractures provides good clinical outcomes. However, few studies have investigated the insertion sequence of the distal screws, although long screw insertion into the distal fragment is technically demanding. The purpose of this study was to investigate a correlation between the insertion sequence of the distal screws and the screw insertion difficulty. METHODS: Medial and lateral anatomical locking plates were closely fitted to the medial and lateral sides of the 10 intact humerus bone models on the computer. Most distal screws have 2 patterns: the screw was inserted from the lateral side first followed by insertion from the medial side (group 1) or from the medial side first followed by insertion from the lateral side (group 2). We calculated the target area wherein the second screw can be inserted. RESULTS: The length of the first most distal screw in group 2 was significantly longer than that in group 1 (58.4 vs. 49.8 mm, p < 0.05). The target areas in both groups were divided into the distal and proximal areas. The distal and proximal areas in group 1 were 91.6 and 61.6 mm2, respectively, and those in group 2 were 191.1 and 11.3 mm2, respectively. The distal area in group 2 was significantly greater than in the other areas (p < 0.05). CONCLUSIONS: In parallel plate fixation for distal humeral fracture, most distal screws could be more easily inserted from the medial side first followed by insertion from the lateral side than from the lateral side first followed by insertion from the medial side.