Hisao Moritomo

Preoperative, Computer Simulation-based, Three-dimensional Corrective Osteotomy for Cubitus Varus Deformity with Use of a Custom-designed Surgical Device

BACKGROUNDnCubitus varus deformity after a supracondylar fracture classically includes varus, extension, and internal rotation components. However, to our knowledge, no reliable surgical method for three-dimensional corrective osteotomy has been established. We developed an intraoperative guide system involving a custom-made surgical template designed on the basis of a three-dimensional computer simulation incorporating computed tomography (CT) data. We aimed to investigate the feasibility of this novel technique for correcting cubitus varus deformity.nnnMETHODSnThirty consecutive patients (twenty-three males and seven females) with a cubitus varus deformity resulting from the malunion of a distal humeral supracondylar fracture were included in this study. Between October 2003 and May 2011, the patients underwent a three-dimensional corrective osteotomy with use of a custom-made surgical template. The patients were then followed for a minimum of twelve months. We evaluated radiographic parameters, including the humerus-elbow-wrist angle and tilting angle, as well as the ranges of motion of the elbow and shoulder at the time of the most recent follow-up. An overall clinical evaluation was performed.nnnRESULTSnBone union was achieved at a mean of four months after surgery. The mean humerus-elbow-wrist angle and tilting angle on the affected side improved significantly from 18.2° (varus) and 25.0°, respectively, before surgery, to 5.8° (valgus) and 38.0°, respectively, after surgery. Hyperextension of the elbow and internal rotation of the shoulder were normalized in all patients. Early plate breakage was observed in one patient. One patient had mild recurrence of varus deformity. Twenty-seven patients had an excellent result, three had a good result, and none had a poor result.nnnCONCLUSIONSnThree-dimensional corrective osteotomy with the use of a custom-made surgical template that is designed and produced on the basis of computer simulation is a feasible and useful treatment option for cubitus varus deformity.

The Distal Interosseous Membrane: Current Concepts in Wrist Anatomy and Biomechanics

The distal interosseous membrane (DIOM) of the forearm acts as a secondary stabilizer of the distal radioulnar joint (DRUJ) when the dorsal and palmar radioulnar ligaments of the triangular fibrocartilage complex are cut. Recent anatomical studies revealed that thickness of the DIOM varies widely among specimens and the distal oblique bundle (DOB) exists within the DIOM in 40% of specimens. The DOB originates from the distal one-sixth of the ulnar shaft and runs distally to insert on the inferior rim of the sigmoid notch of the radius. The mean thickness of the DIOM without a DOB was 0.4 mm, which was significantly thinner than 1.2 mm with a DOB. Biomechanical studies have shown that the DOB is an isometric stabilizer of the forearm during pronosupination. The presence of a DOB was shown to have a significant impact on DRUJ stability. Innate DRUJ laxity in the neutral forearm position was greater in the group without a DOB than in the group with a DOB. Ulnar shortening with the osteotomy performed proximal to the attachment of the DIOM had a more favorable effect on stability of the DRUJ compared with the effect of distal osteotomy, especially in the presence of a DOB. The longitudinal resistance to ulnar shortening was significantly greater in proximal shortening than in distal shortening. It also suggested that the DIOM is of great importance in the management of concomitant ulnar-side injuries in distal radius fracture.

Three-dimensional suitability assessment of three types of osteochondral autograft for ulnar coronoid process reconstruction

BACKGROUNDnOsteochondral autografts with use of the olecranon tip, lateral radial head, or proximal radial head have been employed for coronoid process reconstruction. However, it is unclear which autograft is most suitable for coronoid articular configuration. We assessed 3-dimensional articular facet suitability of 3 osteochondral autografts for coronoid process reconstruction.nnnMETHODSnWe performed 3-dimensional computed tomography of 20 elbows to compare the articular facet configuration between the coronoid process and the ipsilateral olecranon tip, lateral radial head, and proximal radial head. We measured the area of the proximity region (≤2.0 mm) between the articular facets of the coronoid process and 3 osteochondral autografts, the covering rate defined as the percentage area of the coronoid articular facet occupied by the proximity region, the location of the proximity region center, and the percentage of the removed ulnohumeral articular facet.nnnRESULTSnThe covering rate was significantly higher with an olecranon graft than with radial head grafts. The regional center of a proximal radial head graft was significantly medial compared with that of olecranon and lateral radial head grafts. The olecranon graft used an average of 13.8% of the ulnohumeral articular facet.nnnCONCLUSIONSnAn olecranon graft was most suitable for defects of the coronoid process involving the tip, and a proximal radial head graft was most suitable for defects of the coronoid process involving the anteromedial rim. The use of an olecranon graft for reconstruction of 50% of the height of the coronoid process does not cause concern for gross elbow instability.

The distal oblique bundle of the distal interosseous membrane of the forearm.

The distal interosseous membrane (DIOM) of the forearm is on the distal side of the central band of the interosseous membrane, spanning the radius and ulna at the dorsal region of the pronator quadratus muscle. Recent anatomical studies have revealed that the thickness of the DIOM varies widely among specimens (0.5–2.6 mm), and an obvious thick fiber within the DIOM, called the distal oblique bundle (DOB), exists in 40% of specimens.1,2 The DOB originates from the distal ulna 54u2009mm (on average; range, 50–57 mm) proximal to the ulnar head and runs distally to insert on the dorsal inferior rim of the sigmoid notch of the radius (Fig. 1a,b). The DOB has an anatomical relationship with the triangular fibrocartilage complex (TFCC) (Fig. 2), both of which probably work as isometric collateral ligaments of the distal radioulnar joint (DRUJ) because the ulnar insertions of the DOB and the deep limbs of the radioulnar ligament almost coincide with the course of the axis of forearm rotation.3 n n n nFig. 1a,b n nDistal interosseous membrane of the right cadaver wrist. (a) Dorsal view of the distal oblique bundle (DOB) and the central band. (b) The distal radius with the distal interosseous membrane and TFCC viewed from the dorsoulnar side. The ulna has been ... n n n n n nFig. 2 n nAnatomical relationship between DOB and TFCC, which comprises the ulnocarpal ligamentous complex (UCLC), disk, and palmar and dorsal radioulnar (RU) ligaments. UT, ulnotriquetral ligament; UC, ulnocapitate ligament; UL, ulnolunate ligament. n n n nThe TFCC is the primary soft-tissue DRUJ stabilizer, and the DIOM acts as a secondary stabilizer of the DRUJ when the dorsal and palmar radioulnar ligaments of the TFCC are cut.4,5 In normal situations, the influence of the DIOM on DRUJ stability is relatively inconsequential. However, after a TFCC injury, an ulnar head resection, or a Sauve-Kapandji procedure, the DIOM has a more important role in the stability of the ulnar head or ulnar stump. The clinical relevance of the DIOM includes its stabilizing effect on the DRUJ in ulnar shortening procedures. Recent study has revealed that ulnar shortening with the osteotomy performed proximal to the attachment of the DIOM has a more favorable effect on stability of the DRUJ as compared to distal osteotomy, especially in the presence of a DOB.6 The longitudinal resistance to ulnar shortening is significantly greater in proximal shortening than in distal shortening. These results suggest that proximal ulnar shortening in the presence of a robust DIOM could be a risk factor for nonunion, and for patients with ulnocarpal abutment but no instability of the DRUJ, it may be advantageous to perform a distal osteotomy.

Effect of wrist position on distal radioulnar joint stability: A biomechanical study

We investigated distal radioulnar joint (DRUJ) stability in different wrist positions and examined the relative contribution of each ligamentous component of the triangular fibrocartilage complex (TFCC) to DRUJ stability. We used nine fresh‐frozen cadavers. The humerus and ulna were fixed at 90° elbow flexion. The radiocarpal unit was translated relative to the ulna in dorsopalmar directions with the wrist in five positions. Displacement of the unit was measured by an electromagnetic tracking device. Magnitudes of displacement were compared between different wrist positions in various sectioning stages: ulnocarpal ligament (UCL) sectioning, radioulnar ligaments (RUL) sectioning, and extensor carpi ulnaris (ECU) floor sectioning. Wrist position and sectioning stage significantly influenced the displacement. In intact wrists, the displacement in wrist extension was significantly lower than that in neutral. However, after UCL sectioning, there were no longer any significant differences. After RUL sectioning, the displacement in radial deviation was significantly lower than that in neutral. Following ECU floor sectioning, there were no longer any significant differences. Thus, in intact wrists, DRUJ stability in wrist extension is likely due to tightening of the UCL. After complete RUL sectioning, DRUJ is stabilized in radial deviation due to tightening of the ECU floor.

Cylindrical Corrective Osteotomy for Madelung Deformity Using a Computer Simulation: Case Report

We report an adolescent patient with Madelung deformity that we successfully treated by cylindrical corrective osteotomy of the distal radius. We used customized surgical guides, which were designed based on preoperative 3-dimensional computer simulation.

Anatomy and Clinical Relevance of the Ulnocarpal Ligament

The ulnocarpal ligament, or ulnocarpal ligamentous complex (UCLC),1 is anatomically divided into the ulnocapitate, ulnotriquetral, and ulnolunate ligaments, though, macroscopically, these three ligaments are often confluent and indistinguishable from each other. The ulnotriquetral, ulnocapitate, and ulnolunate ligaments originate together at the fovea of the ulnar head and the base of the ulnar styloid. These ligaments, along with the palmar radioulnar (RU) ligament, extend distally like a fan in the coronal plane and insert at the palmar aspects of the triquetrum, capitate, and lunate (Figs. 1, u200b,2).2). The three ligaments of the UCLC merge firmly with the palmar RU ligament. The palmar RU ligament also merges with the dorsal RU ligament on the ulnar side, and they attach together on the ulnar fovea and the ulnar styloid process. This one compound ligamentous complex (UCLC and two RU ligaments), which extends in two perpendicular planes to attach the carpus (in the coronal plane) and the radius (in the transverse plane) to the ulna, is essential for coordination of the distal radioulnar joint (DRUJ) and the ulnocarpal joint.2 n n n nFig. 1 n nDissection of a human right wrist demonstrating the ulnocarpal ligament complex viewed from the dorsal side (a) and the palmar side (b). The ulnotriquetral, ulnocapitate, and ulnolunate ligaments originate together at the fovea of the ulnar head and ... n n n n n nFig. 2 n nAnatomic relationship between ECU sheath floor, prestyloid recess, and triangular fibrocartilage complex (TFCC), which comprises ulnocarpal ligamentous complex (UCLC), disk, and palmar and dorsal radioulnar (RU) ligaments. n n n nThe ulnocapitate ligament is the most superficial of the three ulnocarpal ligaments.3 It attaches not directly to the triangular fibrocartilage complex (TFCC) but to the palmar portion of the fovea region of the ulnar head, which is a slight depression at the base of the ulnar styloid process. At the fovea, the ulnocapitate ligament merges with the deep fibers of the palmar RU ligament.3 From the fovea, the ulnocapitate ligament passes distally, just anterior to the junction between the other ulnocarpal ligaments, and inserts on the ulnopalmar aspect of the capitate. The ulnotriquetral ligament originates mainly from the palmar RU ligament, and some fibers originate from the palmar radial aspect of the ulnar styloid process.3 It inserts at the proximal and ulnar surfaces of the triquetrum. The ulnolunate ligament originates proximally from the palmar RU ligament, thus attaching indirectly to the ulna. The ulnolunate ligament is continuous with the short radiolunate ligament and attaches to the palmar cortex of the lunate just as the short radiolunate ligament does. n nThe extensor carpi ulnaris (ECU) sheath floor is a part of the infratendinous extensor retinaculum, which originates from the dorsal aspect of the triquetrum and inserted on the dorsal and ulnar aspects of the ulnar styloid (Fig. 2). The ECU sheath floor firmly blends with the dorsal RU ligament on the dorsal ulnar aspect of the ulnar fovea and the ulnar styloid. Therefore, the ECU sheath floor, the dorsal and palmar RU ligaments, the articular disk, and the UCLC together form a u shape when viewed from the ulnar side (Fig. 3a). n n n nFig. 3 n nUlnar view (a) and palmar views (b) of a right cadaver wrist. a The ECU sheath floor, the dorsal and palmar RU ligaments, the articular disc, and the UCLC together form a u shape. The ulnar head and the ECU are removed. b There is a “soft spot” ... n n n nThere is a “soft spot” between the ulnotriquetral ligament and ECU sheath floor that is easy to identify by palpation (Fig. 3b). This portion is covered by a thin capsule that forms the anterior wall of the prestyloid recess, which is an area where the meniscus homologue does not cover the ulnar styloid process, thereby creating a pouch, variable in size and shape.4 This soft spot is used as a 6U portal in wrist arthroscopy. In the ulnopalmar view of a three-dimensional (3D) computed tomography (CT) arthrogram, the prestyloid recess appears as a small bulge that is anterodistal to the ulnar styloid and distinguishable from the palmar bulge of the DRUJ capsule (Fig. 4). The narrow area between the two bulges is the ulnar insertion of the UCLC and palmar RU ligament. It is worth noting that this portion is the common lesion of a foveal avulsion of the TFCC. In a foveal TFCC avulsion, especially in cases with a positive fovea sign (a localized tenderness on the palmar aspect of the fovea and ulnar styloid), this portion is often disrupted and filled with loose scar tissue. We have reported open repair of a foveal tear of the TFCC using a palmar approach.5 The advantage of this approach, compared with the dorsal approach, is that iatrogenic damage to the dorsal RU ligament and ECU sheath floor is avoided, while it provides satisfactory views of the disrupted foveal insertions, UCLC and palmar RU ligament. n n n nFig. 4 n nThe ulnopalmar view of a 3D CT arthrogram of a right wrist in which dye was injected in the radiocarpal and distal RU joints. The prestyloid recess is depicted as a small bulge anterodistal to the ulnar styloid and distinguishable from the palmar bulge ... n n n nIn vivo 3D studies on the ulnocarpal ligaments have shown that carpal movements that occur during wrist hyper–radial extension or hyperextension result in substantial strain to the ulnocapitate and ulnotriquetral ligaments and on the foveal and palmar styloid insertions of the TFCC.6 Considering that the ulnotriquetral ligament has another origin on the palmar aspect of the ulnar styloid, which is eccentric from the center of forearm rotation (fovea), it is easily seen that the change in length of this fascicle would be increased by forearm supination. Strain of this fascicle during forearm supination may thus affect the tension of the foveal insertion. Based on these findings, one major injury mechanism of a TFCC foveal avulsion can be excessive traction of the UCLC, especially the ulnocapitate ligament, caused by wrist hyper–radial extension or hyperextension with forearm supination (Fig. 5). This theory agrees with the fact that more than half of the patients with traumatic TFCC foveal avulsion were caused by a fall on the outstretched hand and had a positive fovea sign.5 n n n nFig. 5 n nA simulated TFCC foveal avulsion by excessive traction of the UCLC, especially the ulnocapitate ligament, caused by wrist hyper–radial extension with the forearm supination. A right cadaver wrist is viewed from the distal and palmar side. n n n nIn cases with nonreparable TFCC disruption, TFCC reconstruction is considered. We made use of the UCLC to reconstruct the TFCC because a remnant of UCLC is often retained even in cases with severe ulnar disruption of TFCC (Fig. 6). In our preceding cadaver study, our palmar reconstruction restored stability despite only the palmar portion of the TFCC being reconstructed.7 In our technique, we focused on reconstructing the palmar deep RU ligament rather than the dorsal deep RU ligament, because the most common form of instability is dorsal displacement of the distal ulna with respect to the radius.8 Stuart et al reported in a cadaveric study that the palmar RU ligament provided the greatest restraint to dorsal ulnar translocation.9 Moreover, one previous cadaver study demonstrated that volar dislocation of the ulna relative to the radius did not occur even when the RU ligaments were totally excised, as long as the interossous membrane was intact.10 n n n nFig. 6 n nIllustrations of palmar reconstruction of TFCC that used a UCLC remnant, which is viewed from the palmar and ulnar side. The palmaris longus tendon graft was passed through slits made in the UCLC. The graft was then sutured to the UCLC and the palmar ... n n n nThe UCLC an important role in stabilizing the ulnocarpal joint. The UCLC firmly merges with the palmar RU ligament, which provides the greatest restraint to dorsal ulnar translocation. Knowing the anatomy and function of the UCLC is worthwhile for understanding the pathomechanism of foveal TFCC avulsion and the palmar surgical approach for TFCC repair or reconstruction.

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

BACKGROUNDnAn 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 inxa0vivo and 3-dimensional motion analysis.nnnMETHODSnMagnetic 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.nnnRESULTSnUlnohumeral 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.nnnCONCLUSIONnPatients 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.

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.

Palmar reconstruction of the triangular fibrocartilage complex for instability of the distal radioulnar joint: a biomechanical study.

We developed a new triangular fibrocartilage complex reconstruction technique for distal radioulnar joint instability in which the palmar portion of the triangular fibrocartilage complex was predominantly reconstructed, and evaluated whether such reconstruction can restore stability of the distal radioulnar joint in seven fresh cadaver upper extremities. Distal radioulnar joint instability was induced by cutting all soft-tissue stabilizers around the distal ulna. Using a palmar approach, a palmaris longus tendon graft was sutured to the remnant of the palmar radioulnar and ulnocarpal ligaments. The graft was then passed through a bone tunnel created at the fovea and was sutured. Loads were applied to the radius, and dorsopalmar displacements of the radius relative to the ulna were measured using an electromagnetic tracking device in neutral rotation, 60° supination and 60° pronation. We compared the dorsopalmar displacements before sectioning, before reconstruction and after reconstruction. Dorsopalmar instability produced by sectioning significantly improved in all forearm positions after reconstruction.