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.

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.

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.

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

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

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

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

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

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

The morphologic change of the elbow with flexion contracture in upper obstetric brachial plexus palsy.

BACKGROUND: Contracture of the elbow after obstetric brachial plexus palsy (OBPP) is well known; however, details of the 3-dimensional (3D) morphologic changes in the elbow joint in OBPP have not been clarified. This study aimed to clarify the 3D morphologic changes in the elbow joint by focusing on the distal humerus with flexion contracture in upper OBPP. We tested the hypothesis that the shape of the distal humerus with flexion contracture in upper OBPP is hypoplastic in the trochlea, capitellum, and olecranon fossa. METHODS: We retrospectively studied 20 patients with elbow flexion contracture and residual OBPP. The approximate radius of the distal humerus, the shortest distance between the olecranon and coronoid fossa, and the size of the olecranon fossa were measured and compared between the affected and normal sides using 3D bone models to assess the distal humerus morphology. RESULTS: The average radius of the distal humerus was smaller on the affected side than on the normal side. Furthermore, the average distance between the olecranon and coronoid fossa was greater and the average size of the olecranon fossa was smaller on the affected side than on the normal side. The size of the distal humerus was significantly smaller and the olecranon fossa was significantly shallower on the affected side. CONCLUSIONS: Consistent with our original hypothesis, the distal humerus with flexion contracture in upper OBPP was hypoplastic. The shallow olecranon fossa might prevent full extension of the elbow even though soft tissue contracture release is performed. We recommend evaluation of the morphology of the olecranon fossa to determine the treatment plan for elbow flexion contracture with OBPP.

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

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

Rotational Corrective Osteotomy for Malunited Distal Diaphyseal Radius Fractures in Children and Adolescents.

PURPOSE: To report our method of computer-planned rotational corrective osteotomy for malunited distal diaphyseal radius fractures in children and adolescents using a custom jig and to review the results of 4 cases. METHODS: Four patients (mean age, 13 years; range, 11-16 years) underwent computer-planned rotational corrective osteotomy for malunited distal diaphyseal radius fracture using a custom jig. We retrospectively evaluated their radiographic and clinical data. RESULTS: In patients who had marked restriction of forearm supination before osteotomy, the mean arc of forearm supination improved from 5° before surgery to 79° after surgery. Angular deformity on x-ray, range of forearm rotation, and grip strength all improved after surgery. Mild and moderate pain reported by 1 and 2 patients, respectively, was resolved after surgery. CONCLUSIONS: Computer-planned rotational corrective osteotomy for malunited distal diaphyseal radius fracture in children and adolescents using a custom jig is a strategy that facilitates the surgical procedure by accurately correcting both rotational and angular deformities on 1 plane in a single procedure. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

In Vivo 3-Dimensional Kinematics of Thumb Carpometacarpal Joint During Thumb Opposition.

PURPOSE: This study primarily aimed to demonstrate the screw-home rotation of the thumb carpometacarpal (CMC) joint and the function of surrounding ligaments during thumb oppositional motion. METHODS: A 3-dimensional kinematic analysis of the thumb CMC joint was conducted using data derived from computed tomography of 9 healthy volunteers. Scans were obtained in the neutral forearm and wrist position and the thumb in maximum radial abduction, maximum palmar abduction, and maximum opposition. The movements of the first metacarpal and the palmar and dorsal bases on the trapezium during thumb oppositional motion from radial abduction through palmar abduction were quantified using a coordinate system originating on the trapezium. In addition to the kinematic analyses, the length of virtual ligaments, including the anterior oblique, ulnar collateral, dorsal radial, dorsal central (DCL), and posterior oblique ligament (POL), were calculated at each thumb position. RESULTS: From radial abduction to opposition of the thumb through palmar abduction, the first metacarpal was abducted, internally rotated, and flexed on the trapezium. The palmar base of the first metacarpal moved in the palmar-ulnar direction, and the dorsal base moved in the palmar-distal direction along the concave surface of the trapezium. Although the DCL and POL lengthened, the lengths of other ligaments did not change significantly. CONCLUSIONS: During thumb oppositional motion, internal rotation of the first metacarpal occurred, with the palmar base rotating primarily with respect to the dorsal base. The DCL and POL may be strained in thumb functional positions. CLINICAL RELEVANCE: Kinematic variables indicated a screw-home rotation of the thumb CMC joint and the contribution of the dorsal ligaments to the stability of the rotation on the pivot point.

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.

A comparison of corrective osteotomies using dorsal and volar fixation for malunited distal radius fractures.

PURPOSE: This study aimed to compare clinical results and to restore radiographic parameters of corrective osteotomy for malunited distal radius fracture using a volar locking plate with a dorsal plate. METHODS: We retrospectively studied 28 consecutive patients with symptomatic malunited distal radius fractures followed up for more than 12 months who underwent corrective osteotomy with a dorsal buttress plate (n = 9) or a volar locking plate (n = 19). Volar tilt (VT), radial inclination (RI), and ulnar variance (UV) were radiographically evaluated. Clinical examination parameters included pain, wrist and forearm ranges of motion (ROM), grip strength, and Mayo Modified Wrist Score (MMWS). RESULTS: The volar group had a significantly greater VT undercorrection for - 9.4° than did the dorsal group for - 1.2° (p < 0.001). Major complications requiring plate removal occurred in six of nine patients in the dorsal group and two of 19 patients in the volar group. The complication ratio was significantly greater in the dorsal group than in the volar group (p < 0.05). Improvements in forearm and wrist ROM, grip strength, and MMWS did not differ significantly between groups. CONCLUSIONS: Opening wedge osteotomy of the radius using a volar locking plate is preferable to dorsal buttress fixation in terms of surgical and technical demands and frequency of complications, but VT correction is insufficient. Surgeons should be aware of the mismatch between the plate and the volar surface of the malunited distal radius.

Physeal bar resection using a patient-specific guide with intramedullary endoscopic assistance for partial physeal arrest of the distal radius.

The partial physeal arrest of the distal radius could result in progressive deformities and functional problems of the wrist. Despite being the most preferred surgical intervention, physeal bar resection (Langenskiöld procedure) is technically demanding. This manuscript aims to illustrate the technical tricks and present an illustrative case of premature physeal arrest of the distal radius managed with a novel method for the Langenskiöld procedure, involving complete removal of the bar using a patient-specific guide in combination with an intramedullary endoscopy technique that facilitated direct observation.

In Vivo Scaphoid Motion During Thumb and Forearm Motion in Casts for Scaphoid Fractures.

PURPOSE: In nonsurgical treatment for acute undisplaced or minimally displaced scaphoid waist fractures, immobilization of both wrist and thumb can be an option. However, in vivo scaphoid motion during forearm and thumb motion with the wrist immobilized in a cast has not been measured. Therefore, we examined the in vivo kinematics of the scaphoid during forearm and thumb motion with cast immobilization. METHODS: Ten healthy right wrists of 10 male volunteers were included. These wrists were immobilized in a short-arm spica cast with the thumb in a position of volar abduction and then were scanned with the forearm in supination, neutral rotation, and pronation using computed tomography. Next, these wrists were scanned with a forearm gauntlet cast in place with the thumb abducted radially and opposed with the forearm positioned in neutral rotation. From these data, the 3-dimensional position of the third metacarpal and scaphoid was analyzed. RESULTS: From forearm supination to pronation, the scaphoid showed 0.2° radial deviation, 0.4° pronation, and 8.3° extension. The third metacarpal showed 14.6° ulnar deviation, 6.5° pronation, and 1.6° flexion. During thumb opposition from radial abduction, the scaphoid showed 2.9° radial deviation, 0.4° supination, and 7.2° extension and the third metacarpal showed 4.5° ulnar deviation, 2.8° pronation, and 5.5° extension. CONCLUSIONS: The scaphoid was not completely immobilized by either cast. However, the scaphoid motion during forearm and thumb motion was not significant. CLINICAL RELEVANCE: Several high-quality studies have shown that undisplaced or minimally displaced scaphoid waist fractures can be successfully treated with casts. Movement of scaphoid and wrist during forearm rotation or thumb motion with a cast may not be sufficient to have a negative impact on the outcome of scaphoid fracture using a cast.

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.

In vivo three-dimensional elbow biomechanics during forearm rotation.

BACKGROUND: It is unclear how elbow kinematics changes during forearm rotation. This study investigated in vivo 3-dimensional elbow kinematics during forearm rotation. METHODS: We studied 12 normal elbows using in vivo 3-dimensional computed tomography data in maximum forearm supination, neutral, and maximum pronation with the elbows in extension. We measured the motion of the radius and ulna relative to the humerus using a markerless bone registration technique and the contact area of the radiocapitellar joint, proximal radioulnar joint, and ulnohumeral joint using a proximity mapping method. RESULTS: When the forearm rotated from the supinated position to the pronated position, the radius showed significant varus rotation, internal rotation, and extension relative to the humerus. The center of the radial head significantly translated anteriorly, proximally, and laterally. The ulna significantly rotated in valgus, and the deepest point on the sagittal ridge of the trochlear notch translated medially with forearm pronation. The contact area of the radiocapitellar joint was largest in pronation. The contact area of the proximal radioulnar joint was largest in supination. The contact area of the ulnohumeral joint showed no significant change during forearm rotation. CONCLUSIONS: In pronation, because of the proximal migration of the radial head, the radiocapitellar joint was most congruent compared with other positions. The proximal radioulnar joint was most congruent in supination. The ulnohumeral joint congruency was not affected by forearm rotation. This study provides useful information for understanding 3-dimensional elbow motion and joint osseous stability related to forearm rotation.

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.

Three-dimensional in vivo kinematics during elbow flexion in patients with lateral humeral condyle nonunion by an image-matching technique.

BACKGROUND: An established nonunion of the lateral humeral condyle often reveals elbow instability and accompanying pain. The purpose of this study was to obtain 3-dimensional and quantitative information about the pathologic kinematics of the ulnohumeral joint with nonunion of the lateral humeral condyle by an in vivo and 3-dimensional motion analysis. METHODS: Magnetic resonance or computed tomography images of the elbows of 14 patients were acquired in 3 positions between full extension and full flexion. We evaluated ulnohumeral motion and calculated the change in the length of the medial collateral ligament during elbow flexion. RESULTS: Ulnohumeral motion was associated with an excessive lateral shift of ulnar movement. In addition, the distal part of the ulna was rotated in the varus direction, leading to a decrease in the carrying angle. The ulna tended to exhibit internal rotation from full extension to 90° of flexion of the elbow. With further flexion, the ulna rotated externally and returned to its neutral position. Furthermore, the length of the medial collateral ligament increased with an increase in the elbow flexion angle. CONCLUSION: Patients with lateral humeral condyle nonunion showed excessive lateral shift of the ulna and ulnar axial rotation. Also, the lateral shift caused an osseous protrusion of the medial trochlea, leading to elongation of the medial collateral ligament.