Changes in Distance Between the Flexor Pollicis Longus Tendon and Volar Locking Plate: An Ultrasonographic Study.

PURPOSE: Flexor pollicis longus rupture is a major complication after volar locking plate fixation of distal radius fractures. Although the distance between the flexor pollicis longus tendon and the plate (plate-tendon distance) measured by ultrasonography is used to predict tendon rupture risk, the timing of the ultrasonography can affect the measurements. Therefore, this study aimed to analyze the chronological change of the plate-tendon distance between the tendon and plate. METHODS: A total of 166 wrists underwent the plate-tendon distance measurement twice or more times within 15 months after surgery. Longitudinal ultrasonography scans with the wrist in a neutral position and the thumb flexed were used to measure the plate-tendon distance. The plate-tendon distances at 0-5 months, 5-10 months, and 10-15 months after surgery were compared. A multiple linear regression analysis was performed to evaluate the influence of the interval between surgery and examination, Soong grade, and plate type on the plate-tendon distance. RESULTS: The plate-tendon distance decreased as the interval between surgery and examination increased. The plate-tendon distance was an average of 2.0 ± 1.1 mm, 1.4 ± 0.9 mm, and 1.2 ± 0.9 mm at 0-5 months, 5-10 months, and 10-15 months after surgery, respectively. Significant differences were observed between 0-5 months and 5-10 months and between 5-10 months and 10-15 months after surgery. A multiple linear regression showed that significant predictors of the plate-tendon distance were the intervals between surgery and examination and Soong grade. CONCLUSIONS: The plate-tendon distance decreased as the time since surgery increased. When ultrasonography is used for the assessment of tendon rupture risk, it should be considered that the plate-tendon distance decreases as the interval between the surgery and examination increases. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognosis IV.

Risk of nerve injury during elbow arthroscopy: ultrasonographic evaluation of preoperative patients.

BACKGROUND: To clarify the real risk of nerve injury during elbow arthroscopy, the distances of the radial and median nerves to the elbow joint were investigated using ultrasonography in patients who underwent surgery. METHODS: A total of 35 patients who underwent arthroscopic surgery of the elbow were investigated. The distances of the nerves to the capsule and bony landmarks were measured using ultrasonography. The radial nerve distances were measured at the capitellum, joint space, radial head, and radial neck levels. The median nerve distances were measured at the trochlear, joint space, and coronoid process levels. The patients were divided into 2 groups: nine patients in the hydrarthrosis (HA) group and 26 patients in the non-hydrarthrosis (non-HA) group. HA was defined as the intra-articular effusion on magnetic resonance imaging scans. RESULTS: The radial nerve ran closer to the capsule at the radial neck level in the HA group than in the non-HA group (2.0 mm vs. 5.9 mm, P < .01). In the non-HA group, the radial nerve ran closer to the radial head than in the HA group (6.3 mm vs. 8.5 mm, P = .01). The median nerve ran closer to the capsule at the trochlear level in the HA group than in the non-HA group (5.2 mm vs. 8.8 mm, P < .01). Nerves at a distance of ≤2 mm from the capsule were found in 7 patients at the radial neck of the radial nerve and in 2 patients at the trochlear region of the median nerve in the HA group. In the non-HA group, they were found in 3 patients at the radial head and in 1 patient at the joint space of the radial nerve. CONCLUSIONS: The dangerous locations for nerve injury during elbow arthroscopy vary according to hydrarthrosis, and this risk should be recognized during arthroscopic surgery.

Arthroscopic Partial Excision of the Radial Head for Advanced Rheumatoid Elbow.

We treated humeroradial joint disorder in rheumatoid elbows with arthroscopic partial excision of the radial head, in which the radial head is minimally resected under arthroscopy to ensure adequate joint space and articular congruity. To examine the effect of this method, we investigated outcomes using a retrospective case series. The hypothesis of this study was that this method decreases symptoms related to the humeroradial joint and ensures articular congruity. Since 2008, we have performed arthroscopic partial excision of the radial head for 14 patients (15 rheumatoid elbows) with more than 2 years of follow-up. Surgical indications for this method were motion pain with crepitus around the humeroradial joint and joint narrowing and sclerosis on plain radiography. After synovectomy, the surface of the radial head was resected 4 to 5 mm under arthroscopy, ensuring adequate joint space and articular congruity. Osteophyte removal and anterior capsular release were performed if necessary. At the final follow-up of 54 months, pain around the humeroradial joint had resolved in all cases. Range of motion improved from 115° flexion, -39° extension, 55° pronation, and 54° supination preoperatively to 127° flexion, -27° extension, 60° pronation, and 65° supination postoperatively. The articular congruity of the humeroradial joint was well maintained at final follow-up, with the exception of 2 cases in which the space decreased after 4 years. Arthroscopic partial excision of the radial head is a promising procedure for improvement of humeroradial symptoms. This method is effective, even for advanced cases, and should be considered before total arthroplasty. [Orthopedics. 2022;45(4):209-214.].

Corrective osteotomy for hyperextended elbow with limited flexion due to supracondylar fracture malunion.

BACKGROUND: Extension deformity of the distal humerus after a malunited supracondylar fracture can restrict elbow flexion. Here we report a computer-assisted operative procedure and review the results of clinical cases in which corrective surgery was performed. METHODS: The medical records of the patients who underwent corrective osteotomy for hyperextended elbow malunion of the distal humerus with limited elbow flexion (flexion angle ≤100°) were reviewed retrospectively. Osteotomy was performed using patient-specific instruments designed based on preoperative 3-dimensional computer simulation. RESULTS: Three patients, a 55-year-old woman and two 12-year-old boys, met the inclusion criteria. The angles of hyperextension of the affected distal humerus were 29°, 29°, and 25°, respectively. The range of flexion/extension of the elbow motion in the first patient improved from 95°/25° preoperatively to 140°/-10° postoperatively, in the second patient from 100°/20° to 145°/5°, and in the third patient from 80°/25° to 140°/10°. Bone union was achieved in all patients. There were no major complications. The corrective operations not only improved elbow flexion but also increased the total range of motion in the elbow by rebuilding the anterior curve of the distal humerus. CONCLUSIONS: Correction of the extension deformity of the distal humerus after a malunited supracondylar fracture is a reasonable option for patients older than 10 years with restricted elbow flexion. Preoperative computer simulation and the use of patient-specific instruments can be a useful alternative that enables accurate deformity correction and improves the total range of motion.

Anconeus Muscle-Pedicle Bone Graft With Periosteal Coverage for Osteochondritis Dissecans of the Humeral Capitellum.

BACKGROUND: Treatment of advanced osteochondritis dissecans (OCD) of the capitellum is controversial, especially in moderate-sized lesions. PURPOSE: To establish a treatment algorithm for capitellum OCD, we tried to determine the utility of and problems associated with anconeus muscle-pedicle bone graft with periosteal coverage (ABGP) for the treatment of moderate-sized articular OCD defects of the capitellum. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: According to our protocol for elbow OCD, 16 patients (15 males, 1 female; age range, 12-17 years; mean age, 14.4 years) with a moderate-sized OCD lesion of the humeral capitellum were treated with ABGP. All patients had a full-thickness, unstable OCD lesion that was 10 to 15 mm in diameter. Clinical results and postoperative images, including radiographs and magnetic resonance imaging (MRI), were evaluated at a mean follow-up of 31 months (range, 24-66 months). RESULTS: All but 1 patient had functional improvement after the procedure and returned to previous sporting activities within 6 months. One female patient needed 1 year for functional recovery due to development of postoperative chronic regional pain syndrome (CRPS). Two patients required additional surgery, including shaving of the protruding cartilage, and they returned to their previous level of activity. Mean arc of range of flexion-extension motion was 117° preoperatively and 129° at follow-up (P = .031). Mean elbow function as assessed with the clinical rating system of Timmerman and Andrews was 136 preoperatively and 186 at follow-up (P = .00012). Bony union of the graft as demonstrated by trabecular bone bridging on radiography was obtained within 3 months in all patients. Postoperative MRI was examined for 14 patients at 6 to 12 months after the procedure; the MRIs showed near-normal articular surface integrity in 9 of the 14 patients (64%) and underlying bony structure in 10 of the 14 patients (71%). CONCLUSION: Improvement after ABGP was obtained within 6 months in all except 1 patient, who developed CRPS. Postoperative radiography and MRI revealed near-normal articular surface integrity or underlying bony structure. This procedure is useful as a surgical option for a moderate-sized articular OCD lesion in the elbow.

Prediction of forearm bone shape based on partial least squares regression from partial shape.

BACKGROUND: Computer-assisted corrective osteotomy using a mirror image of the normal contralateral shape as reference is increasingly used. Instead, we propose to use the shape predicted by statistical learning to deal with cases demonstrating bilateral abnormality, such as bilateral trauma, congenital disease, and metabolic disease. METHODS: Computed tomography (CT) scans of 100 normal forearms were used in this study. The whole bone shape was predicted from its partial shape based on statistical learning of the other 99 bones. Accuracy was evaluated by average symmetric surface distance (ASD), and translational and rotational errors. RESULTS: ASDs for predicted shapes were 0.71-1.03 mm. Mean absolute translational and rotational errors were 0.48-1.76 mm and 0.99-6.08°, respectively. CONCLUSION: Normal bone shape was predicted with an acceptable accuracy from its partial shape using statistical learning. Predicted shape can be an alternative to a mirror image, which may enable reduced radiation exposure and examination costs.

Three-dimensional analysis of osteophyte formation on distal radius following scaphoid nonunion.

BACKGROUND: The purposes of this study were to quantitatively analyze osteophyte formation of the distal radius following scaphoid nonunion and to investigate how fracture locations relate to osteophyte formation patterns. METHODS: Three-dimensional surface models of the scaphoid and distal radius were constructed from computed tomographic images of both the wrists of 17 patients' with scaphoid nonunion. The scaphoid nonunions were classified into 3 types according to the location of the fracture line: distal extra-articular (n = 6); distal intra-articular (n = 5); and proximal (n = 6). The osteophyte models of the radius were created by subtracting the mirror image of the contralateral radius model from the affected radius model using a Boolean operation. The osteophyte locations on the radius were divided into 5 areas: styloid process, dorsal scaphoid fossa, volar scaphoid fossa, dorsal lunate fossa, and volar lunate fossa. Osteophyte volumes were compared among the areas and types of nonunion. The presence or absence of dorsal intercalated segment instability (DISI) deformity was also determined. RESULTS: The distal intra-articular type exhibited significantly larger osteophytes in the styloid process than the distal extra-articular type. Furthermore, the proximal type exhibited significantly larger osteophytes in the dorsal scaphoid fossa than the distal extra-articular type. Finally, the distal intra- and extra-articular types were more associated with DISI deformity and tended to have larger osteophytes in the lunate fossa than the proximal type. CONCLUSION: The pattern of osteophyte formation in the distal radius determined using three-dimensional computed tomography imaging varied among the different types of scaphoid nonunion (distal extra-articular, distal intra-articular, and proximal). The results of this study are clinically useful in determining whether additional resection of osteophytes or radial styloid is necessary or not during the treatment of the scaphoid nonunion.

Corrective osteotomy assisted by computer simulation for a malunited intra-articular fracture of the distal humerus: two case reports.

INTRODUCTION: Intra-articular malunion after fractures of the distal humerus can cause pain, stiffness and, consequently, osteoarthritis in the long run. Although corrective osteotomy for intra-articular malunion has been reported, it is still technically challenging and needs careful preoperative evaluation and planning. Here, we present two cases of corrective osteotomy assisted by preoperative three-dimensional (3-D) computer simulation. MATERIALS AND METHODS: We present two cases of malunited intra-articular fracture of the distal humerus, which was treated by corrective osteotomy with the aid of 3-D computer simulation. One case was initially treated with closed reduction and pinning, and the other was initially treated with open reduction and internal fixation. Both of them had pain and severely limited range of motion in the elbow due to intra-articular malunion. 3-D models of the bilateral humeri were created on a computer using computed tomography (CT) data. The deformity was analyzed by superimposing the model of the affected humerus on the mirrored model of the contralateral normal humerus. Osteotomy, reduction and fixation were simulated preoperatively on the computer. The actual surgery was performed exactly according to the preoperative 3-D computer simulation. RESULTS: The operative procedures were performed successfully according to the computer simulation. Range-of-motion exercises started 3 days and immediately after the surgery in cases 1 and 2, respectively. Two years after surgery, there were no complaints of pain or instability. The range of elbow motion was 5°-140° and 15°-125° in cases 1 and 2, respectively. Plain radiographs and CT scans showed good reconstruction of the articular surface. CONCLUSION: 3-D computer simulations can be useful in preoperative planning for intra-articular corrective osteotomy for complex malunion of the distal humerus.

Postoperative accuracy analysis of three-dimensional corrective osteotomy for cubitus varus deformity with a custom-made surgical guide based on computer simulation.

BACKGROUND: For correction of cubitus varus deformity resulting from supracondylar fracture of the humerus, we developed an operative method with use of a custom-made surgical guide, designed on the basis of 3-dimensional (3D) computer simulation with computed tomography data. The purpose of this study was to investigate the postoperative accuracy of this system in clinical cases. METHODS: Subjects included 17 consecutive patients (13 males and 4 females) with cubitus varus deformity after supracondylar fracture. Patients underwent 3D corrective osteotomy with use of a custom-made surgical guide. Postoperative computed tomography scan was performed after bone union diagnosis on plain radiographs, and postoperative 3D bone models were compared with preoperative simulation by surface registration technique. In addition, we evaluated radiographic parameters (humerus-elbow-wrist angle and tilting angle) and range of elbow motion at the most recent follow-up. RESULTS: Mean errors in 3D corrective osteotomy were 0.6° ± 0.7° in varus-valgus rotation, 0.8° ± 1.3° in flexion-extension rotation, 2.9° ± 2.8° in internal-external rotation, 1.7 ± 1.8 mm in anterior-posterior translation, 1.3 ± 1.8 mm in lateral-medial translation, and 7.1 ± 6.3 mm in proximal-distal translation. The mean humerus-elbow-wrist angle on plain radiographs of the affected side was 15° in varus before surgery and improved to 6° in valgus after surgery. The mean tilting angle of the affected side was 31° before surgery and improved to 40° after surgery. CONCLUSION: The 3D correction of cubitus varus deformity was performed accurately within the allowable error limits.

Volar morphology of the distal radius in axial planes: a quantitative analysis.

To investigate the cause of rupture of the flexor pollicis longus (FPL) after volar plate fixation of distal radius fractures, previous studies have examined the shape of the distal radius in the sagittal plane or in the lateral view. However, there are no reports on the anatomical shape of the volar surface concavity of the distal radius in the axial plane. We hypothesized that this concavity might contribute to the mismatch between the plate and the surface of the radius. To test this hypothesis, we constructed three-dimensional models of the radius and FPL based on computed tomography scans of 70 normal forearms. We analyzed axial cross-sectional views with 2 mm intervals. In all cases, the volar surface of the distal radius was concave in the axial plane. The concavity depth was maximum at 6 mm proximal to the palmar edge of the lunate fossa and progressively decreased toward the proximal radius. FPL was closest to the radius at 2 mm proximal to the palmar edge of the lunate fossa. The volar surface of the distal radius was externally rotated from proximal to distal. These results may help to develop new implants which fit better to the radius and decrease tendon irritation.

Three-dimensional corrective osteotomy using a patient-specific osteotomy guide and bone plate based on a computer simulation system: accuracy analysis in a cadaver study.

BACKGROUND: The accuracy of three-dimensional (3-D) corrective osteotomy using a patient-specific osteotomy guide and bone plate based on computer simulation was investigated. METHODS: Six fresh-frozen cadaver upper limbs were used. A patient-specific osteotomy guide designed to realize a preplanned osteotomy was set on the distal humerus and distal radius, and the error in the setting location was evaluated. After the osteotomy, the surgical site was fixed using a patient-specific bone plate designed to exactly fit the anatomical shape of the postoperative bone model. The postoperative results were compared with the preoperative simulation. RESULTS: The errors in the guide location on the humerus and radius were <1.5° and 1.0 mm and <1.0° and 1.0 mm, respectively. The plate fixation errors of the humerus and radius were <2.0° and 1.5 mm and <1.0° and 1.0 mm, respectively. CONCLUSIONS: The system is sufficiently feasible to realize precise 3-D deformity correction of a limb.