Yohei Kawanishi

Arthroscopic-Assisted Reduction and Percutaneous Fixation for Coronal Shear Fractures of the Distal Humerus: Report of Two Cases

Two patients with fractures of the capitellum and trochlea were treated with arthroscopic-assisted reduction and percutaneous fixation. This option may only be appropriate for straightforward fractures with no posterior comminution that can be reduced and visualized adequately.

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

The accuracy of three‐dimensional (3‐D) corrective osteotomy using a patient‐specific osteotomy guide and bone plate based on computer simulation was investigated.

Does cubitus varus cause morphologic and alignment changes in the elbow joint

BACKGROUND In cubitus varus after pediatric supracondylar fracture, late development of trochlear deformity causing additional varus angulation and joint misalignment relating to late complications of the tardy ulnar nerve palsy or posterolateral rotatory instability have been suggested. However, it is unclear whether these morphologic and alignment changes of the elbow joint occur in cubitus varus. The object of this study was to investigate morphologic changes of the bones and alignment changes of the elbow joint in longstanding cubitus varus using 3-dimensional computer bone models created from computed tomography data. MATERIALS AND METHODS We studied 14 patients with longstanding cubitus varus after pediatric supracondylar fractures. Three-dimensional bone models of the bilateral humerus, radius, and ulna were created from computed tomography data. We compared the morphology and alignment of the elbow joint between the affected side and contralateral unaffected side. RESULTS The posterior trochlea, distal part of the lateral capitellum, diameters of the radial head, and articular surface of the ulna in cubitus varus were larger than those of the contralateral elbow. In the ulna, the convex portion of the trochlear notch shifted laterally in cubitus varus. Joint alignment in cubitus varus was affected by a shift of the ulna to a more distal and medial position with external rotation and flexion. CONCLUSIONS In longstanding cubitus varus, the morphology and alignment of the elbow joint are observed to differ from those of the normal side.

The association between cubital tunnel morphology and ulnar neuropathy in patients with elbow osteoarthritis

BACKGROUND Morphologic changes in the cubital tunnel during elbow motion in patients with elbow osteoarthritis have not been examined in vivo. We examined changes in cubital tunnel morphology during elbow motion and characteristics of medial osteophyte development to elucidate whether cubital tunnel area and medial osteophyte size are factors contributing to cubital tunnel syndrome in patients with elbow osteoarthritis. METHODS We performed computed tomography of 13 primary osteoarthritic elbows in patients with cubital tunnel syndrome (group A) and 25 primary osteoarthritic elbows in patients without cubital tunnel syndrome (group B) at full extension, 90° of flexion, and full flexion. Cubital tunnel area, humeral and ulnar osteophyte area, and proportion of osteophytes within the cubital tunnel were analyzed at each position. RESULTS Humeral osteophytes and osteophyte proportion within the cubital tunnel were larger at full flexion (24.7 mm(2) and 49.9% in group A; 18.7 mm(2) and 39% in group B) and 90° of elbow flexion (20.3 mm(2) and 45.3% in group A; 10.2 mm(2) and 30.2% in group B) than at full extension (9.0 mm(2) and 31.3% in group A; 2.3 mm(2) and 12.5% in group B). These parameters were significantly greater in group A than in group B at full extension and 90° of flexion. CONCLUSIONS The effect of medial osteophytes on the ulnar nerve, especially on the humeral side, rather than narrowing of the cubital tunnel, may be a causative factor for cubital tunnel syndrome with elbow osteoarthritis.

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.

In vivo 3-dimensional analysis of stage III Kienböck disease: pattern of carpal deformity and radioscaphoid joint congruity.

PURPOSE To examine 3-dimensional carpal alignment and radioscaphoid joint (RSJ) congruity among normal wrists and those with Lichtman stage III Kienböck disease or scapholunate dislocation (SLD). METHODS We conducted 3-dimensional analysis based on computed tomographic data to compare 10 wrists of stage III Kienböck disease (5 IIIa and 5 IIIb) with 5 normal wrists and 3 wrists with SLD. A markerless bone registration technique was used to investigate the 3-dimensional position of the scaphoid relative to the radius. To evaluate RSJ congruency, the inferred contact area between the scaphoid proximal pole and the distal radius was calculated from 3-dimensional bone models. RESULTS The scaphoid position was not significantly different from normal wrists in stage IIIa Kienböck disease. Stage IIIb Kienböck disease was meaningfully associated with a flexed scaphoid and proximal translation of the centroid, but not dorsal translation of the scaphoid proximal pole, where RSJ congruity was preserved. With SLD, the scaphoid flexed to the same extent as that in stage IIIb Kienböck disease, and the proximal pole translated dorsally together with the capitate, producing RSJ incongruity. CONCLUSIONS The patterns of carpal collapse differed between stage IIIb Kienböck disease and SLD in terms of RSJ congruity. Our study showed that stage IIIb Kienböck disease did not involve dorsal subluxation of the scaphoid proximal pole and that RSJ congruity was retained, unlike SLD. CLINICAL RELEVANCE Our results suggest that carpal collapse in Kienböck disease is not associated with RSJ incongruity, which may explain why there are asymptomatic patients with Kienböck disease and carpal collapse.

A comparison of 3-D computed tomography versus 2-D radiography measurements of ulnar variance and ulnolunate distance during forearm rotation

Positive ulnar variance is associated with ulnar impaction syndrome and ulnar variance is reported to increase with pronation. However, radiographic measurement can be affected markedly by the incident angle of the X-ray beam. We performed three-dimensional (3-D) computed tomography measurements of ulnar variance and ulnolunate distance during forearm rotation and compared these with plain radiographic measurements in 15 healthy wrists. From supination to pronation, ulnar variance increased in all cases on the radiographs; mean ulnar variance increased significantly and mean ulnolunate distance decreased significantly. However on 3-D imaging, ulna variance decreased in 12 cases on moving into pronation and increased in three cases; neither the mean ulnar variance nor mean ulnolunate distance changed significantly. Our results suggest that the forearm position in which ulnar variance increased varies among individuals. This may explain why some patients with ulnar impaction syndrome complain of wrist pain exacerbated by forearm supination. It also suggests that standard radiographic assessments of ulnar variance are unreliable.