Ulnar lengthening for children with forearm deformity from hereditary multiple exostoses: a retrospective study from a tertiary medical center.

BACKGROUND: Patients with hereditary multiple exostosis (HME) usually present with forearm deformity with or without radial head dislocation. Ulna lengthening has been proposed to address this condition. Exostosis resection plus ulna lengthening has been adopted in our hospital since 2008, and patients with this condition were retrospectively reviewed. Herein, we aimed to investigate the optimal timing and clinical outcomes of this surgical approach. METHODS: In all, thirty-five patients (40 forearms), including 22 boys and 13 girls, were enrolled in our study from July 2014 to September 2020. We divided the patients into 4 groups based on the age when they received surgery and the status of the radial head. Pronation and supination of the forearm, flexion and extension of the elbow, wrist ulnar deviation and wrist radial deviation, and radiological parameters including ulnar length (UL), ulnar variance (UV), the percentage of radial bowing (RB/RL), radio articular angle (RAA) and carpal slip (CS), were assessed and recorded. RESULTS: The mean UL was significantly improved after surgery in four Groups (P<0.05). In patients with radial head dislocation, we found significant improvement in forearm, wrist function and elbow flexion (p < 0.05). For the patients with radial head dislocation, the juniors demonstrated better improvement in % RB and RAA (p<0.05, p = 0.003 and 0.031). CONCLUSION: Exostosis resection and ulna lengthening with unilateral external fixation can effectively improve the function and radiological parameters of forearm deformity in HME children. For patients with radial head dislocation, early surgery can achieve better results. For patients not associated with radial head dislocation, we recommend regular follow-up and surgical treatment after 10 years of age.

Is a Novel Fluoroscopic Intraoperative Reference System Superior to Conventional Management for Distal Radius Fracture Reduction? A Propensity-matched Comparative Study.

BACKGROUND: Preoperative planning is generally performed to simulate the process of reduction as well as to determine the size and placement of implants in patients undergoing distal radius fracture surgery. We previously described a three-dimensional (3D) digital preoperative planning system for the osteosynthesis of distal radius fractures, and we have developed a novel intraoperative referencing system that superimposes preoperative planning (such as plate position and length) onto fluoroscopic images during surgery; however, its efficacy has not been evaluated compared with conventional planning and surgery. QUESTIONS/PURPOSES: Does use of a novel intraoperative referencing system result in (1) better Mayo wrist scores at 3 and 6 months after surgery and (2) less loss of reduction in terms of ulnar variance, palmar tilt, and radial inclination on plain radiographs taken 1 week, 3 months, and 6 months after surgery compared with conventional preoperative planning? METHODS: Between April 2014 and October 2021, we treated 294 patients with open reduction and volar plate fixation for distal radius fractures. Of 294 patients, 65% (191) underwent surgery using either conventional preoperative planning or a novel intraoperative referencing system. The remaining patients were excluded because they were younger than 18 years, they had some missing medical records related to the clinical outcomes, or they had a previous history of upper extremity injuries. During that time, we generally treated fractures with volar plates when there was: more than 2 mm of stepoff/gap in the articular surface, a dorsal tilt more than 15°, radial inclination less than 15°, or radial shortening more than 5 mm. Generally, we used a flexor carpi radialis approach. In some patients who had dorsal fragments, we added a dorsal approach. At that time, we were developing the new intraoperative referencing system, so it was not used consistently. To arrive at a fair assessment, we opted to perform propensity matching based on age, gender, and AO fracture type. During the period in question, 36% (69 of 191) of patients with distal radius fractures who received a volar plate were treated using our novel intraoperative referencing system, and 64% (122 of 191) had surgery using conventional preoperative planning (control group). Of those, 91% (63 of 69) of patients who were treated with the intraoperative referencing system and 89% (108 of 122) of those in the control group were available for follow-up with all imaging and Mayo wrist scores at least 6 months after surgery. After propensity matching, that left us with two groups of 39 patients, who were well matched in terms of age and fracture type; these were the study groups. We also tried to match them according to gender, but there were fewer patients in the intraoperative referencing group, and the percentage of women for each group differed: 70% (44 of 63) in the intraoperative referencing group and 76% (82 of 108) in the control group. Also, there were fewer men with C3 fractures in the control group. Therefore, 64% (25 of 39) of patients in the intraoperative referencing group were women and 77% (30 of 39) of patients in the control group were women. In the intraoperative referencing group, our novel intraoperative referencing system was used in combination with the 3D digital preoperative planning system for preoperative planning. In the control group, preoperative planning was performed manually in a conventional manner using tracing paper and implant templates or using a digital template. We compared the groups in terms of operative duration, the radiation dose used in surgery, and Mayo wrist scores at 3 and 6 months after surgery. We also compared the groups in terms of loss of reduction on ulnar variance, palmar tilt, and radial inclination on plain radiographs taken 3 months and 6 months after surgery. We considered the plain radiograph taken 1 week after surgery as a baseline. Each item was compared between the image fusion and control groups using a Welch t - test. RESULTS: Mayo wrist scores were no different between the intraoperative referencing system and the control group at 3 months (71 ± 7 versus 72 ± 11, mean difference 1 [95% CI -3.7 to 5.7]; p = 0.07) or at 6 months after surgery (76 ± 6 versus 79 ± 11, mean difference 3 [95% CI -3.5 to 7.9]; p = 0.12). There were no differences in surgical duration or radiation doses between the intraoperative referencing and control groups. We found only a small advantage in favor of the intraoperative referencing system in terms of loss of reduction on ulnar variance (3 months after surgery: 0.2 ± 0.4 mm versus 0.6 ± 0.7 mm, mean difference 0.4 mm [95% CI 0.15 to 0.69]; p = 0.003, 6 months after surgery: 0.4 ± 0.6 mm versus 0.8 ± 0.8 mm, mean difference 0.4 mm [95% CI 0.05 to 0.73]; p = 0.02 for the intraoperative referencing system and the control group, respectively). This difference in radial shortening was so small that it was not likely to have been clinically important. CONCLUSION: We found no clinically important advantages from the use of our novel intraoperative referencing system except a slight improvement in ulnar variance. Therefore, we recommend against its use in everyday practice at this time. However, future improvements may lead to better clinical outcomes, so we plan further investigations. LEVEL OF EVIDENCE: Level III, therapeutic study.

Comparison of corticocancellous bone graft from the anterolateral metaphysis of the distal radius versus iliac crest for the treatment of unstable scaphoid nonunion with humpback deformity.

BACKGROUND: Corticocancellous bone grafting from the iliac crest is acceptable treatment for unstable scaphoid nonunion with a viable proximal pole. However, harvesting graft from the iliac crest is associated with donor site morbidity and the requirement of general anesthesia. Thus, bone grafting from the anterolateral metaphysis of the distal radius (DR) can be a treatment option. However, no study has compared the clinical effect between the two grafting techniques. METHODS: From 2014 to 2019, patients with unstable scaphoid nonunion with humpback deformity underwent corticocancellous bone grafting from the anterolateral metaphysis of the DR (group DR) or iliac crest (group IC). Humpback deformity was determined by evaluating the scapholunate angle (SLA) ≥ 60°, intrascaphoid angle (ISA) ≥ 45°, and radiolunate angle (RLA) ≥ 15° from preoperative radiographs and computed tomography scans. The SLA, ISA, and RLA served to gauge carpal alignment. The operative time, grip strength, active range of motion (ROM), the Modified Mayo Wrist score (MMWS), and Disabilities of Arm, Shoulder, and Hand (DASH) score were assessed postoperatively. RESULTS: Thirty-eight patients qualified for the study (group DR, 15; group IC, 23). Union rates did not differ by patient subset (group DR, 100%; group IC, 95.7%; P = .827), and grip strength, ROM, MWS, and DASH score were similar between groups at the last follow-up. The operative time (minutes) was significantly shorter in group DR (median, 98; quartiles, 80, 114) than in group IC (median, 125; quartiles, 105, 150, P < .001). The ISA, RLA, and SLA improved postoperatively in both groups (P < 0.001). The degree of restoring carpal alignment, as evaluated by SLA, showed superior correction capability in group DR (median, 25.3% quartiles, 21.1, 35.3, P < 0.05). Donor site complications were not significantly different between the groups. CONCLUSIONS: Corticocancellous bone graft from the anterolateral metaphysis of the DR for unstable scaphoid nonunion is associated with a shorter operation time and comparable results with that from the iliac crest in regard to union, restoration of carpal alignment, and wrist function. LEVEL OF EVIDENCE: Level III.

Effect of the Sauvé-Kapandji method on the wrist contact surface for distal radial ulnar joint disorders.

BACKGROUND: The Sauvé-Kapandji (S-K) method is a surgical procedure performed for chronic deformities of the distal radial ulnar joint (DRUJ). Changes to the joint contact surface from pre- to postoperatively under physiological in vivo conditions have not yet been determined for this useful treatment. The aim of the present study was therefore to compare the articular contact area of the wrist joint between before and after the S-K method for DRUJ disorders. METHODS: The SK method was performed for 15 patients with DRUJ osteoarthritis and ulnar impaction syndrome. We calculated the Mayo Wrist Score as the patient's clinical findings and created 3-dimensional bone models of cases in which the S-K method was performed and calculated the contact area and shift in the center of the contact area using customized software. RESULTS: The Mean modified Mayo Wrist Score improved significantly from 60.3 preoperatively to 80.3 postoperatively (P < 0.01). Scaphoid contact area to the radius increased significantly from 112.6 ± 37.0 mm2 preoperatively to 127.5 ± 27.8 mm2 postoperatively (P = 0.03). Lunate contact area to radius-ulna was 121.3 ± 43.3 mm2 preoperatively and 112.5 ± 37.6 mm2 postoperatively, but this decrease was not significant (P = 0.38). Contact area ratio of scaphoid to lunate increased significantly from 1.01 ± 0.4 preoperatively to 1.20 ± 0.3 postoperatively (P = 0.02). Postoperative translations of the center of the scaphoid and lunate contact areas were decomposed into ulnar and proximal directions. Ulnar and proximal translation distances of the scaphoid contact area were 0.8 ± 1.7 mm and 0.4 ± 0.6 mm, respectively, and those of the lunate contact area were 1.1 ± 1.7 mm and 0.4 ± 1.1 mm, respectively. This study revealed changes in wrist contact area and center of the contact area before and after the S-K method. CONCLUSION: These results may accurately indicate changes in wrist joint contact area from pre- to postoperatively using the S-K method for patients with DRUJ disorder. Evaluation of changes in contact area due to bone surface modeling of the wrist joint using 3DCT images may be useful in considering surgical methods.

Location of the posterior interosseous nerve in relation to common lateral approaches to the elbow.

PURPOSE: The risk of posterior interosseous nerve (PIN) injury during surgical approaches to the lateral elbow varies depending on the chosen approach, level of dissection, and rotational position of the forearm. Previous studies evaluated the trajectory of the PIN in specific surgical applications to reduce iatrogenic nerve injuries. The goal of this study is to examine the location of the PIN using common lateral approaches with varying forearm rotation. METHODS: The Kaplan, extensor digitorum communis (EDC) split, and Kocher approaches were performed on 18 cadaveric upper extremity specimens. Measurements were recorded with a digital caliper from the radiocapitellar (RC) joint and the lateral epicondyle to the point where the PIN crosses the approach in full supination, neutral, and full pronation with the elbow at 90°. The ratio of the nerve's location in relation to the entire length of the radius was also evaluated to account for different-sized specimens. RESULTS: The PIN was not encountered in the Kocher interval. For Kaplan and EDC split, with the forearm in full supination, the mean distance from the lateral epicondyle to the PIN was 52.0 ± 6.1 mm and 59.1 ± 5.5 mm, respectively, and the mean distance from the RC joint to the PIN was 34.7 ± 5.5 mm and 39.3 ± 4.7 mm, respectively; with the forearm in full pronation, the mean distance from the lateral epicondyle to the PIN was 63.3 ± 9.7 mm and 71.4 ± 8.3 mm, respectively, and the mean distance from the RC joint to the PIN was 44.2 ± 7.7 mm and 51.1 ± 8.7 mm, respectively. CONCLUSIONS: The PIN is closer to the lateral epicondyle and RC joint in the Kaplan than EDC split approach and is not encountered during the Kocher approach. The PIN was not encountered within 26 mm from the RC joint and 39 mm from the lateral epicondyle in any approach and forearm position and is generally safe from iatrogenic injury within these distances.

Reconstruction of the proximal radius with 3D-printed personalized prosthesis after tumor resection: case series.

BACKGROUND: Giant cell tumor of bone (GCTB) (Campanacci III) or malignant tumors extend to the epiphyseal region of the proximal radius, and intra-articular resection of the proximal radius is often needed. In the present study, we present the patients who underwent reconstruction of the proximal radius with 3D-printed personalized prosthesis after tumor resection, aiming to describe the prosthesis design and surgical technique and evaluate the clinical outcomes of this method. METHODS: Between November 2018 and January 2021, 9 patients received radial hemiarthroplasty with 3D-printed personalized prostheses after tumor resection. The pathologic diagnosis was GCTB (Campanacci III) in 7 patients, osteosarcoma (IIB) in 1 patient, and synovial sarcoma (IIB) in 1 patient. The range of motion (ROM) and strength in terms of elbow flexion/extension and forearm supination/pronation were evaluated. Pain was assessed by the visual analog scale (VAS) preoperatively and at each follow-up visit. To evaluate the functional outcome, the Mayo Elbow Performance Score (MEPS) system and the Musculoskeletal Tumor Society (MSTS) scoring system were administered at each follow-up visit. Complications and oncological outcomes were recorded. RESULTS: The patients were followed from 24 to 51 months, with a median follow-up of 35 months. No patients were lost to follow-up. During the follow-up, local recurrence and metastasis were not observed. The VAS score improved from a median of 5 points (range 4-7) preoperatively to 1 point (range 0-2) at the last follow-up visit. The mean MEPS score was 88.5% (83-93), and the mean MSTS score was 25.3 (24-27) at the last follow-up visit. No complications such as infection and aseptic loosening were detected. CONCLUSIONS: The implantation of a 3D-printed personalized prosthesis after proximal radial resection showed excellent oncologic outcomes and postoperative function at short-term follow-up and is a viable alternative method for reconstruction of the proximal radius bone defect after tumor resection.

The impact of anatomic alignment on radiocapitellar pressure following radial head arthroplasty.

BACKGROUND: The incidence of radial head fractures is increasing, and radial head arthroplasty (RHA) is being more frequently used as treatment for irreparable fractures. Our objective was to compare radiocapitellar pressure between the native joint and 2 radial head prosthesis conditions: (1) a prosthetic head that was aligned to the forearm axis of rotation and (2) the same prosthesis with an axisymmetric nonaligned head. METHODS: Ten cadaveric specimens received a pressfit radial head prosthesis (Align; Skeletal Dynamics) for both prosthetic testing conditions. Anatomic alignment (AL) was defined as the prosthetic head aligned to the forearm axis of rotation. Axisymmetric alignment (AX) was defined as the prosthetic radial head aligned to the axis of the prosthetic stem. Axial load was applied with the elbow in extension and the forearm pronated. Data were collected using a Tekscan 4000 sensor. RESULTS: The mean pressure in the AL and AX groups were significantly higher than the mean pressure in the native joint. Compared with the native joint, the mean pressure was 19% higher in the AL group and 56% higher in the AX group. Peak pressure beyond 5 MPa occurred in 0 specimens in the native joint group, in 1 specimen (10%) in the AL group, and in 5 specimens (50%) in the AX group. DISCUSSION: Our results demonstrated that a pressfit radial head prosthesis aligned with the forearm axis of rotation yields capitellar pressures that were more similar to the native condition than a nonaligned pressfit prosthesis. These findings suggest that anatomic alignment may optimize capitellar wear properties, improving the long-term durability of radial head arthroplasty.

Physeal Fractures of the Distal Ulna: Incidence and Risk Factors for Premature Growth Arrest.

BACKGROUND: The aim of this study is to assess the rate of distal ulnar growth arrest following physeal fracture and to identify specific risk factors for premature physeal closure. METHODS: A retrospective review of patients with a distal ulnar physeal fracture was performed at a single United States children's hospital. Patients without 6-month follow-up were excluded. Patient demographics, injury characteristics, treatment, and outcomes were abstracted. Fractures were classified by the Salter-Harris (SH) system. All follow-up radiographs were reviewed for changes in ulnar variance or signs of premature physeal arrest. RESULTS: Fifty-six children with distal ulnar physeal fracture at a mean age of 10.7±3.3 years were included with a mean follow-up of 1.9 years. The most common fracture pattern was a SH II (52.7%), versus SH I (29.1%), SH III (9.1%), and SH IV (9.1%). Of displaced fractures (41.1%), the mean translation was 40.2±38.3% the and mean angulation was 24.8±20.9 degrees. Eleven fractures (19.6%) demonstrated radiographic signs of growth disturbance, including 3 patients (5.4%) with growth disturbance but continued longitudinal growth and 8 patients (14.3%) with complete growth arrest. The average ulnar variance was -3.4 mm. Three patients underwent subsequent surgical reconstruction including ulnar lengthening with an external fixator, distal ulna completion epiphysiodesis with distal radius epiphysiodesis, and ulnar corrective osteotomy. Patients with displaced fractures and SH III/IV fractures were more likely to develop a growth disturbance (34.8% vs. 3.2%, P =0.003; 50.0% vs. 11.1%, P =0.012, respectively). Children with less than 2 years of skeletal growth remaining at the time of injury had a higher risk of growth disturbance (46.2% vs. 9.5%, P =0.007). CONCLUSIONS: SH III and IV fractures are more common injury patterns in the distal ulna compared with the distal radius. Growth disturbance or growth arrest occurs in ~20% of distal ulnar physeal fractures. Displaced fractures, intra-articular fractures, fractures requiring open reduction, and older children are at increased risk of distal ulnar growth arrest and should be followed more closely. LEVEL OF EVIDENCE: Level IV--case series.

Guided Growth With Minifragment Plates for Angular Deformities in the Distal Radius in Skeletally Immature Patients. Preliminary Results.

INTRODUCTION: Growth modulation allows correction of progressive ulnar deviation of the distal radius in skeletally immature patients, which may occur as a consequence of various pathologies. The aim of this study is to evaluate the radiographic results and complication rate in a series of patients treated with minifragment plates. METHODS: The medical records of 12 patients who underwent guided growth with a minifragment plate on the radial aspect of the distal radius as a consequence of angular deformities in the distal radius were retrospectively reviewed. Demographic data, radiographic changes, and complication rate were analyzed. RESULTS: A total of 14 wrists and forearms were evaluated. The mean age at which surgery was performed was 10.5 years (interquartile range: 9.0 to 11.3). The average time between placement and removal of the material was 28.7 months (SD: 8,89). In each case, a general improvement of the radiographic parameters was obtained. There were 3 postoperative complications, but only 1 of them required reintervention (broken metaphyseal screw). CONCLUSIONS: Hemiepiphysiodesis using a minifragment plate is a treatment that respects the surgical anatomy and offers an alternative surgical option for angular deformities of the distal radius in children. LEVEL OF EVIDENCE: Level IV.

Reconstruction of congenital pseudarthrosis of the radius with a vascularized tibial periosteal transplant: A case report.

Congenital pseudarthrosis of the forearm poses a considerable challenge because of its rarity. The objective of this report is to introduce a novel surgical technique for its treatment. Here, we document a case of congenital pseudarthrosis of the radius in a 3-year-old boy diagnosed with type-1 neurofibromatosis. The surgical treatment involved the excision of approximately 9 cm of native radial periosteum and a bifocal radius osteotomy, which was supplemented with a vascularized tibial periosteal transplant to facilitate bone healing. Anastomosis between the anterior tibial vessels and radial vessels was performed. No immediate or late postoperative complications were observed. After 3 weeks, a robust callus formation was observed, and during a follow-up examination 3 years and 4 months later, a wide range of active forearm rotation was noted. This report suggests that vascularized periosteal flaps show promise as a viable treatment option for congenital pseudarthrosis of the forearm. They offer an alternative to vascularized fibular grafts or single-bone forearm constructs.

Reconstruction Strategy for Upper Extremity Defects After Bone Tumor Resection Based on 3D Customized Bone Cement Mold.

BACKGROUND: Reconstructing bone defects in the upper extremities and restoring their functions poses a significant challenge. In this study, we describe a novel workflow for designing and manufacturing customized bone cement molds using 3D printing technology to reconstruct upper extremity defects after bone tumor resection. METHODS: Computer tomography data was acquired from the unaffected upper extremities to create a detachable mold, which can be customized to fit the joint precisely by shaping the bone cement accordingly. Fourteen patients who underwent reconstructive surgery following bone tumor resection in the proximal humerus (13 cases) or distal radius (1 case) between January 2014 and December 2022 were retrospectively evaluated. The medical records of this case series were reviewed for the demographic, radiological, and operative data. Metastasis, local recurrence, and complication were also reviewed. Additionally, Musculoskeletal Tumor Society Score (MSTS) and Visual Analogue Scale (VAS) were used to assess clinical outcomes. RESULTS: The mean follow-up period was 49.36 ± 15.18 months (range, 27-82 months). At the end of follow-up, there were no cases of metastasis or recurrence, and patients did not experience complications such as infection, dislocation, or implant loosening. Two cases complicated with subluxation (14.3%), and 1 case underwent revision surgery for prosthetic fracture (7.1%). The average MSTS score was 23.2 ± 1.76 (77.4%, range, 66.7%-86.7%), and the postoperative VAS score was 1.86 ± 1.03 (range, 1-4), which was significantly lower than that before surgery (average preoperative VAS score was 5.21 ± 2.00 (range, 2-8)) (P < .001). CONCLUSION: Customized 3D molds can be utilized to shape bone cement prostheses, which may serve as a potential alternative for reconstructing the proximal humerus and distal radius following en bloc resection of bone tumors. This reconstruction strategy offers apparent advantages, including precise matching of articular surfaces and comparatively reduced costs.

Cancellous bone graft from the distal radius and headless screw fixation for unstable scaphoid waist nonunion.

PURPOSE: Cancellous bone harvested from the distal radius has been used in various hand surgeries, but studies on its use in scaphoid waist nonunions are insufficient. We investigated the usefulness of cancellous bone graft from the distal radius and headless screw fixation in unstable scaphoid waist nonunion. METHODS: Thirty-one patients who underwent cancellous bone graft from the distal radius and headless screw fixation for unstable scaphoid waist nonunion with follow-up for at least 1 year were included. Bone union time, the number of patients with bone union at six and 12 weeks, total number of patients with bone union at last follow-up, and bone union on the computed tomography (CT) image at postoperative six weeks were evaluated. Further, pre- and postoperative radiological measurements, such as scaphoid length and height, lateral intra-scaphoid angle, and height-to-length ratio, and functional outcomes were compared. Additionally, inter-observer reliability of radiologic parameters was checked. RESULTS: Bone union was achieved in 29 patients. There were two nonunions (6.5%). Bone union time was 10.7 (range, 6-26) weeks. Eighteen (58%) and 25 patients (80.6%) were diagnosed with bone union on the plain radiographs at six and 12 weeks, respectively. Twenty-two patients (71%) were diagnosed with bone union on CT performed at six weeks. Radiological measurements and functional outcomes improved postoperatively. The scaphoid length showed good inter-observer agreement. CONCLUSIONS: In treating unstable scaphoid waist nonunion, cancellous bone graft from the distal radius and headless screw fixation achieved 93.5% union and improved radiological measurements as well as functional outcomes.

Comparison of three-dimensional printed patient-specific guides versus freehand approach for radial osteotomies in normal dogs: Ex vivo model.

OBJECTIVE: To compare the accuracy of three-dimensional (3D) printed patient-specific guide (PSG) with a freehand (FH) approach for radial osteotomies in ex vivo normal dogs. STUDY DESIGN: Experimental study. ANIMALS: Twenty four ex vivo thoracic limb pairs from normal beagle dogs. METHODS: Computed tomography (CT) images were collected preoperatively and postoperatively. Three osteotomies tested (n = 8/group) were: (1) uniplanar 30° frontal plane wedge ostectomy, (2) oblique plane (30° frontal, 15° sagittal) wedge ostectomy, and (3) single oblique plane osteotomy (SOO, 30° frontal, 15° sagittal, and 30° external). Limb pairs were randomized to a 3D PSG or FH approach. The resultant osteotomies were compared with virtual target osteotomies by surface shape-matching postoperative to the preoperative radii. RESULTS: The mean ± standard deviation osteotomy angle deviation for all 3D PSG osteotomies (2.8 ± 2.8°, range 0.11-14.1°) was less than for the FH osteotomies (6.4 ± 6.0°, range 0.03-29.7°). No differences were found for osteotomy location in any group. In total, 84% of 3D PSG osteotomies were within 5° deviance from the target compared to 50% of freehand osteotomies. CONCLUSION: Three-dimensional PSG improved FH accuracy of osteotomy angle in select planes and the most complex osteotomy orientation in a normal ex vivo radial model. CLINICAL SIGNIFICANCE: Three-dimensional PSGs provided more consistent accuracy, which was most notable in complex radial osteotomies. Future work is needed to investigate guided osteotomies in dogs with antebrachial bone deformities.

Effects of simulated radioulnar synostosis on supination and pronation in cats. A cadaveric study.

OBJECTIVE: To evaluate the effect of an induced synostosis with a screw on pronation and supination in cats. STUDY DESIGN: Ex vivo biomechanical study. SAMPLE POPULATION: A total of 58 feline forelimbs. METHODS: A total of 58 cadaveric feline thoracic limbs were mounted on a custom-built jig with the elbow and carpus flexed at a 90° angle. To exclude any orthopedic disease, radiographs of the forelimbs were performed prior to the mechanical tests. Radioulnar synostosis was imitated with a 2 mm cortical screw through the radius into the ulna in the proximal (Group P; n = 54), middle (Group M; n = 52), and distal (Group D; n = 53) radial diaphysis. The angles of pronation and supination were recorded after manually applying a two-finger tight rotational force to the metacarpus. Rotational tests were performed without a screw (Group N) and with a screw in each of the aforementioned positions. Pairwise comparisons between the groups were performed based on their angles of rotation with a paired t-test with the Benjamini-Hochberg procedure and a mixed model ANOVA. RESULTS: Mean angles of rotation decreased between Group N (129.5 ± 15.9°) and all groups with imitated radioulnar synostosis to a mean angle of 37.5 ± 14.5° (p < .0001). Mean angles of rotation did not differ between the groups with imitated radioulnar synostosis. CONCLUSION: Induced radioulnar synostosis decreases antebrachial rotation by more than two-thirds, regardless of location. CLINICAL SIGNIFICANCE: Implants fixating the radius to the ulna should be avoided in cats, regardless where they are located along the radial diaphysis.

Intraoperative visualization of the posterolateral ulnohumeral joint space is reliable to indicate overlengthening in radial head arthroplasty.

INTRODUCTION: Avoiding overlengthening in radial head arthroplasty (RHA) is essential for the prognosis of the elbow joint. An overlengthening from 2 mm is visible due to widening of the anterolateral ulnohumeral joint space but intraoperatively, this particular joint space is difficult to visualize. The commonly used Kocher approach allows visualization of the posterolateral joint space without additional instruments or further surgical release of the already unstable elbow. The aim of our study was to investigate whether the visualization of the posterolateral joint space is also a reliable method to indicate overlengthening in RHA. MATERIAL AND METHODS: RHA was performed in five human cadaveric specimens with the forearm, wrist, and hand intact. The lateral ligament complex was detached and an anatomic transosseous refixation was performed. Six stages of implantation heights were documented: native joint (1), RHA at the anatomic height (2), + 2 mm (3), + 4 mm (4), + 6 mm (5) and - 2 mm (6). Macroscopic measurement and digital image analysis of the posterolateral and anterolateral ulnohumeral joint spaces were performed. RESULTS: All stages of overlengthening showed a significant increase in posterolateral and anterolateral joint space widening (p < 0.05). The posterior and anterior joint space showed excellent intraclass correlation. CONCLUSION: Visualization of the posterolateral aspect of the ulnohumeral joint space is a reliable indicator for overlengthening in RHA without further compromising an already unstable elbow. Correlation to the findings of the anterolateral ulnohumeral joint space in different implants leads to the assumption that visualization of either the anterior or posterior ulnohumeral joint space is universally applicable to determine overlengthening in RHA, regardless of the type of the radial head implant.

Radiographic evaluation of radial flexion osteotomy effect on static scapholunate instability: a preliminary cadaveric study.

INTRODUCTION: The optimal treatment of chronic scapholunate instability has yet to be established. Scapholunate ligament grafts are still far from being the ideal solution. We conducted an experimental study to evaluate whether flexion-opening wedge osteotomy of the distal radius improves misalignment and avoids rotatory subluxation of the scaphoid in a cadaveric model of static scapholunate dissociative instability. MATERIALS AND METHODS: Radiographic studies were performed on 15 cryopreserved specimens after recreating a model of scapholunate instability by division of the scapholunate interosseous ligament (SLIL) and secondary stabilizers, taking radiographs at baseline, after the instability model, and after distal radius osteotomy. Static and dynamic (under controlled tendon traction) anteroposterior and lateral views were obtained to measure the length (in mm) of the carpal scaphoid and scapholunate interval, scapholunate angle, radio-lunate angle, and palmar tilt of the distal joint surface of the radius and to measure the dorsal scaphoid translation by the concentric circles method. The Wilcoxon test was used for statistical comparisons. RESULTS: The scapholunate interval was significantly decreased after osteotomy in all static anteroposterior views and in all lateral views under tendon traction. Dorsal scaphoid translation was significantly reduced in static lateral view in extension and in dynamic lateral view under 5-pound flexor carpi radialis tendon tension controlled by a digital dynamometer. CONCLUSIONS: Flexion-addition osteotomy of the distal radius appears to improve carpal alignment parameters in a cadaveric model of static scapholunate instability, achieving similar values to those obtained before instability.

Open reduction and internal fixation of modified Mason type III/IV radial head fractures with more than three fragments: an analysis of the clinical outcome and reoperation rate.

PURPOSE: It is generally accepted that a radial head fracture (RHF) with more than three parts is not suitable for repair; therefore, most authors suggest straightforward radial head arthroplasty (RHA). With up to 20% risk for reoperation after RHA, improvement in reduction and fixation techniques may represent a valuable alternative before further extending the indications for arthroplasty. To determine the functional results and radiological failure rate after osteosynthesis of multi-fragmentary RHF with more than three articular fragments. We specifically determined (1) the one-year Broberg and Morrey functional elbow score, (2) duration of fracture healing, (3) complication rate, and (4) number of patients converted to RHA. METHODS: This study is a retrospective single-center case series. All patients who underwent primary osteosynthesis for RHF between 2012 and 2019 were included. Nine patients with an average age of 52 years had an average clinical and/or radiological follow-up of 49 months. RESULTS: The preoperative imaging identified nine fractures with four fragments. Three patients underwent osteosynthesis with plates and screws, whereas six patients underwent osteosynthesis with only screws. The mean Broberg and Morrey score was 95 points. Overall, eight of the nine patients had satisfactory results. All patients retained their radial heads and showed radiological fracture healing. Only two patients presented with low-grade complications requiring no further surgery. CONCLUSION: Our study showed that osteosynthesis of RHF with up to four fragments can achieve good functional results with a low complication rate and seems to be a valid alternative to RHA.

The optimal strategy for 3D-printed uncemented endoprosthesis for the bone defect reconstruction of the distal radius, based on biomechanical analysis and retrospective cohort study.

INTRODUCTION: Prosthetic reconstruction after resecting giant cell tumor of bone (GCTB) of the distal radius has been proposed. However, this is generally associated with various complications. To improve the functional outcomes, we designed a three-dimensional (3D)-printed uncemented endoprosthesis. Meanwhile, using finite-element analysis and clinical observation, an optimization strategy was explored. MATERIALS AND METHODS: We retrospectively analyzed patients with Campanacci III or recurrent GCTB of the distal radius who underwent 3D-printed uncemented endoprosthesis reconstruction. Clinically, according to the different palmar tilts of the endoprosthesis, patients were divided into the biological angle (BA) group and the zero-degree (ZD) group. We recorded and evaluated the differences in functional outcomes and complications between the two groups. Biomechanically, four 3D finite-element models (normal and customized endoprostheses with three different implemented palmar tilts) were developed. RESULTS: We analyzed 22 patients (12 males and 10 females). The median follow-up period was 60 (range, 19-82) months. Of the 22 patients, 11 patients were included in the BA group and the remaining 11 patients were in the ZD group. Both groups showed no significant differences in the range of motion, Mayo score, and disabilities of the arm, shoulder, and hand scores postoperatively. The subluxation rate was significantly lower in the ZD group than in the BA group. The biomechanical results showed similar stress and displacement distribution patterns in the normal and prosthetic reconstruction models. Additionally, the endoprosthesis with 0° palmar tilt showed better biomechanical performance. CONCLUSION: 3D-printed uncemented endoprosthesis provides acceptable midterm outcomes in patients undergoing distal radius reconstruction. Optimizing the design by decreasing the palmar tilt may be beneficial for decreasing the risk of wrist joint subluxation.

Distal Radioulnar Joint: Normal Anatomy, Imaging of Common Disorders, and Injury Classification.

The distal radioulnar joint (DRUJ) is the distal articulation between the radius and ulna, acting as a major weight-bearing joint at the wrist and distributing forces across the forearm bones. The articulating surfaces are the radial sigmoid notch and ulnar head, while the ulnar fovea serves as a critical attachment site for multiple capsuloligamentous structures. The DRUJ is an inherently unstable joint, relying heavily on intrinsic and extrinsic soft-tissue stabilizers. The triangular fibrocartilage complex (TFCC) is the chief stabilizer, composed of the central disk, distal radioulnar ligaments, ulnocarpal ligaments, extensor carpi ulnaris tendon subsheath, and ulnomeniscal homologue. TFCC lesions are traditionally classified into traumatic or degenerative on the basis of the Palmer classification. The novel Atzei classification is promising, correlating clinical, radiologic, and arthroscopic findings while providing a therapeutic algorithm. The interosseous membrane and pronator quadratus are extrinsic stabilizers that offer a minor contribution to the joint's stability in conjunction with the joints of the wrist and elbow. Traumatic and overuse or degenerative disorders are the most common causes of DRUJ dysfunction, although inflammatory and developmental abnormalities also occur. Radiography and CT are used to evaluate the integrity of the osseous constituents and joint alignment. US is a useful screening tool for synovitis in the setting of TFCC tears and offers dynamic capabilities for detecting tendon instability. MRI allows simultaneous osseous and soft-tissue evaluation and is not operator dependent. Arthrographic CT or MRI provides a more detailed assessment of the TFCC, which aids in treatment and surgical decision making. The authors review the pertinent anatomy and imaging considerations and illustrate common disorders affecting the DRUJ. Online supplemental material is available for this article. © RSNA, 2022.

A Novel Method for Treating Distal Radius Diaphyseal Metaphyseal Junction Fracture in Children.

BACKGROUND The treatment of distal radius diaphyseal metaphyseal junction (DMJ) fracture in children is a clinical problem; several treatments are available, but none are very effective. Therefore, this study aimed to report a novel method for treating this fracture using limited open reduction and transepiphyseal intramedullary fixation with Kirschner wire. MATERIAL AND METHODS From January 2018 to December 2019, a total of 15 children (13 boys and 2 girls) with distal radius DMJ fractures with a mean age of 10 years (range: 6-14 years) were included in the study. The operation time, incision length, and X-ray radiation exposure were precisely recorded. All children were followed up regularly. At the final follow-up, clinical outcomes were evaluated according to Price criteria, and complications were recorded. RESULTS The mean operation time of the 15 children was 21.4 min, and the mean incision length was 1.9 cm. The intraoperative X-ray was performed 3.7 times on average. The mean radiographic union of fracture was 4.7 weeks, and the mean time to remove the Kirschner wire was 4.8 weeks for radial instrumentation and 4.7 months for ulnar instrumentation. According to the Price grading evaluation system, clinical outcome was excellent in 14 cases and good in 1 case. Moreover, there were no major complications related to loss of reduction, malunion, nonunion, and physeal arrest of the distal radius. CONCLUSIONS Limited open reduction and transepiphyseal intramedullary fixation with Kirschner wire are effective for treating distal radius DMJ fracture in children, which has the advantages of simple surgical procedures, short operation time, small incision, and less radiation exposure, making it an excellent choice for treating this fracture.