Ligamentoplasty using the ulnotriquetral ligament with wafer procedure for chronic triangular fibrocartilage complex foveal tear: Short-tem outcome.

BACKGROUND: We developed a new ligamentoplasty technique using the ulnotriquetral ligament (UTL) via a palmar approach for cases with dorsal instability of the ulna due to a foveal tear of the triangular fibrocartilage complex (TFCC). The study aimed to evaluate the clinical outcomes of this procedure. METHODS: We retrospectively analyzed 19 cases with foveal tears of TFCC who underwent the ligamentoplasty using UTL. We harvested the UTL from the triquetrum as a pedicle graft, avoiding damage of the connection between the base of the UTL and palmar radioulnar ligament (PRUL) as possible. The graft was flipped proximally and pulled out through the bone tunnel from the ulnar fovea to the ulnar neck, then fixed to the fovea using a tenodesis screw. The function of the TFCC can be reproduced by pulling out the UTL along with the PRUL through the ulnar fovea and re-establishing the PRUL tension. Clinical results were evaluated at least 12 months following surgery. The preoperative and postoperative wrist pain level on a neumerical rating scale (NRS), the radioulnar joint (DRUJ) ballottement test, the range of motion, the grip strength, and the Patient-rated wrist evaluation (PRWE) scores were evaluated. RESULTS: In all cases, the DRUJ ballottement test became negative at the final follow up compared with the normal side on manual examination. The pain levels significantly decreased as reflected by a decrease in NRS from 6.8 to 2.5 at final follow up (p < 0.01). The range of pronation/supination motion was improved from 149° to 157°. The mean PRWE score significantly decreased from 52.1 to 22.8 (p < 0.01). The postoperative pain level on the NRS scale of the three patients poorly improved. One case of the three with the 3 mm positive ulnar variance needed additional ulnar shaft shortening using a plate seven months after the primary procedure. CONCLUSIONS: The ligamentoplasty using UTL efficiently restored the ulnar palmar stability in all 19 cases and significantly decreased the wrist pain and the PRWE scores. STUDY DESIGN: Clinical, retrospective study.

Biomechanical Effects of Radioscapholunate Fusion With Distal Scaphoidectomy and Triquetrum Excision on Dart-Throwing and Wrist Circumduction Motions.

PURPOSE: Distal scaphoid and triquetrum excisions can improve the range of wrist motion after radioscapholunate (RSL) fusion, but little is known about the kinematics of dart-throwing and global circumduction motions. We hypothesized that these excisions could increase the range of motion without causing midcarpal instability. METHODS: Seven fresh-frozen cadaver upper extremities were mounted on a testing apparatus after isolation and preloading of the tendons of the flexor carpi radialis, flexor carpi ulnaris, extensor carpi radialis, and extensor carpi ulnaris. Sequential loadings of the flexor carpi ulnaris and extensor carpi radialis simulated active dart-throwing motion. Passive circumferential loading produced the wrist circumduction motion. We measured the range of wrist motions with an electromagnetic tracking system in 4 experiments: intact, simulated RSL fusion, RSL fusion with distal scaphoid excision, and RSL fusion with distal scaphoid and total triquetrum excisions. To evaluate midcarpal stability, we conducted passive mobility testing of the distal carpal row in the radial, volar, ulnar, and dorsal directions. RESULTS: Radioscapholunate fusion decreased the dart-throwing motion to a mean of 46% of the baseline value; distal scaphoid and triquetrum excisions increased the mean arc to 50% and 62%, respectively. Radioscapholunate fusion diminished the wrist circumduction to a mean of 43% of the baseline value, which increased to a mean of 58% and 74% after distal scaphoid and triquetrum excision, respectively. A significant increase in radial deviation was noted after distal scaphoid excision, and subsequent triquetrum excision significantly increased motion in the ulnar-palmar direction. Regarding midcarpal stability, dorsal translation significantly increased after distal scaphoid and triquetrum excisions. CONCLUSIONS: Distal scaphoid and triquetrum excision after RSL fusion improved both dart-throwing and circumduction motions, but dorsal midcarpal instability occurred. CLINICAL RELEVANCE: Subsequent carpal excisions may improve short-term outcome by increasing motions in a RSL-fused wrist; however, a potential risk of midcarpal instability should be considered.

Lunate fracture healing after partial capitate shortening in Kienböck disease.

BACKGROUND: It is unclear whether lunate fracture types in Kienböck disease correlate with the degree of fracture healing. This study aimed to review the clinical results of stage 3 Kienböck disease treated using partial capitate shortening (PCS) and to evaluate the healing rates of lunate fractures based on the fracture types. METHODS: Twenty-three patients were clinically and radiographically followed up for >2 years after PCS. The preoperative location and postoperative healing of the lunate fracture were evaluated using plain radiography, computed tomography, and/or magnetic resonance imaging. Results were evaluated using the Kienböck scoring system by Nakamura. RESULTS: PCS was clinically effective, demonstrating excellent and good results in 11 and 11 patients, respectively. Pain evaluated using the visual analog scale, wrist extension, flexion motion, and grip strength significantly improved postoperatively (p < 0.01). Fractures were preoperatively detected in all 23 cases. Fracture locations were preoperatively classified into five subtypes based on radiographs: volar pole in five patients, dorsal pole in three, coronal in five, transverse in nine, and ulnar in one. The overall union rate of the lunate fracture was 48%, whereas none of the coronal fractures healed. CONCLUSIONS: PCS was effective in treating stage 3 Kienböck disease. Coronal lunate fractures had a poor healing rate relative to those of the other fracture types. STUDY DESIGN: Clinical, retrospective 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.

Three-Dimensional Kinematic Analysis of the Distal Radioulnar Joint in the Axial-Loaded Extended Wrist Position.

PURPOSE: To assess the wrist joints of healthy volunteers in extended and loaded states versus the unloaded state by using computed tomography (CT) to analyze the in vivo 3-dimensional movements in the distal radioulnar joint (DRUJ). METHODS: The dominant arms of 9 volunteers with healthy wrists were studied. We mounted a compression device onto the elbows in an inverted position. A 0-kg and 7-kg load each was applied during low-dose radiation CT imaging and a bone model was produced. We marked the insertion sites for the 4 radioulnar ligaments stabilizing the DRUJ: palmar superficial radioulnar ligament (PS-RUL), dorsal superficial radioulnar ligament (DS-RUL), dorsal deep radioulnar ligament (DD-RUL), and palmar deep radioulnar ligament (PD-RUL). Using Marai's method, each ligament was virtualized and the length of each simulated ligament was measured. We also computed the 3-dimensional displacement and corresponding rotation of the distal ulna where it comes into contact with the radius in the sigmoid notch. RESULTS: The lengths of palmar ligaments (PS-RUL and PD-RUL) increased significantly under loaded conditions, and although not significant, the length of dorsal ligaments (DS-RUL and DD-RUL) tended to increase. When the wrist was loaded, the ulna rotated toward the open palmar side. CONCLUSIONS: The length of simulated radioulnar ligaments increased when the wrist joint was loaded in an extended position. This kinematic movement of DRUJ separation under a loading condition is different from physiological active movement. CLINICAL RELEVANCE: The 3-dimensional kinematic analysis revealed that palmar radioulnar ligaments were stretched during axial loading, suggesting that a tear of the palmer ligament can result from a fall on an outstretched hand.

Biomechanical study of isolated radial head dislocation.

BACKGROUND: Isolated radial head dislocation is a rare injury with an unclear pathomechanism, and the treatment is controversial. The purpose of the present study was to investigate the biomechanical contributions of the annular ligament, quadrate ligament, interosseous membrane, and annular ligament reconstructions to proximal radioulnar joint stability. METHODS: Five fresh frozen cadaveric upper extremities were amputated above the elbow and solidly fixed on a customized jig. Radial head dislocation was reproduced by sequential sectioning of ligamentous structures and passive mobility testing. Radial head displacement during mobility testing was measured with an electromagnetic tracking device in three forearm rotation positions. The data were compared among different sectioning stages and between two types of simulated ligamentous reconstruction. RESULTS: Lateral displacement of the radial head significantly increased in the neutral forearm rotation after annular ligament sectioning (46 ± 10%, p < 0.05). After quadrate ligament sectioning, we found significant posterior (67 ± 36%, p < 0.05) and lateral (74 ± 24%, p < 0.01) displacement in neutral forearm rotation and pronation. Significant radial head displacement was found in all directions and in all forearm positions after sequential sectioning of the proximal half of the interosseous membrane. Anatomical annular ligament reconstruction stabilized the proximal radioulnar joint except for anterior laxity in neutral forearm rotation (15 ± 6%, p < 0.05). The radial head with Bell Tawse procedure was significantly displaced in all directions. CONCLUSION: The direction of radial head instability varied depending on the degree of soft tissue sectioning and specific forearm rotation. Anterior radial head dislocation may involve more severe ligament damage than other types of dislocation. Anatomical annular ligament reconstruction provided multidirectional radial head stability.

Impact of Distal Ulnar Fracture Malunion on Distal Radioulnar Joint Instability: A Biomechanical Study of the Distal Interosseous Membrane Using a Cadaver Model.

PURPOSE: Certain distal ulna fractures may contribute to distal radioulnar joint (DRUJ) instability. We hypothesized that residual distal ulna translation could affect DRUJ stability by slackening the distal interosseous membrane (DIOM). We aimed to test this hypothesis in a cadaver model. METHODS: We created an ulnar translated distal ulna fracture model in 6 cadavers. Dorsal and palmar displacements of the ulna relative to the radius were measured and DRUJ instability was staged under the following conditions: (1) 0-, 2-, and 4-mm ulnar translation of the distal ulna with an intact triangular fibrocartilage complex (TFCC) and DIOM; (2) 0-, 2-, and 4-mm translations with TFCC divided and an intact DIOM; and (3) a 0-mm translation with TFCC and DIOM divided. RESULTS: With an intact TFCC, dorsal and palmar displacements were not increased with any amount of distal ulna translation. After TFCC division with 0-mm translation, dorsal displacement increased significantly with DRUJ dislocation, whereas palmar displacement increased to a lesser extent with DRUJ subluxation. Palmar displacement gradually increased as the translation increased, and with 4-mm translation the ulnar head displaced to a perched position off the sigmoid notch. With TFCC and DIOM division, displacements increased markedly with DRUJ dislocation both dorsally and palmarly. CONCLUSIONS: Dorsal dislocation occurred when the TFCC was divided regardless of the amount of distal ulna translation. Palmar subluxation occurred when the TFCC alone was divided. Palmar displacement to a perched position occurred because of slackening of the DIOM as a result of translation of the distal ulna. Bidirectional DRUJ instability with dorsal dislocation and palmar displacement to a perched position occurred when the TFCC was divided and the distal ulna was ulnarly translated. CLINICAL RELEVANCE: Bidirectional DRUJ instability might occur when distal ulna translation deformity is associated with TFCC injury because the DIOM loses its function as a secondary stabilizer.

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.

Bidirectional Dislocation of the Distal Radioulnar Joint After Distal Radius Fracture: Case Report.

We report a patient with bidirectional dislocation of the distal radioulnar joint after malunited distal radius fracture, in which the ulnar head dislocated dorsally during forearm pronation and palmarly during supination without manual compression of the ulnar head. The patient had chronic ulnar wrist pain and experienced a painful clunk during forearm rotation. The distal radioulnar joint ballottement test was positive in both the dorsal and palmar directions. Her distal radius was malunited with a 20° dorsal angulation and 18° pronation deformity. A corrective osteotomy of the radius with open repair of the triangular fibrocartilage complex foveal avulsion yielded success. At the 7-year follow-up, there was almost a normal range of wrist and forearm motion, 83% grip strength, no arthritis, and a stable distal radioulnar joint.

Scaphoid tuberosity excursion is minimized during a dart-throwing motion: A biomechanical study.

PURPOSE: The purpose of this study was to determine whether the excursion of the scaphoid tuberosity and therefore scaphoid motion is minimized during a dart-throwing motion. METHODS: Scaphoid tuberosity excursion was studied as an indicator of scaphoid motion in 29 cadaver wrists as they were moved through wrist flexion-extension, radioulnar deviation, and a dart-throwing motion. RESULTS: Study results demonstrate that excursion was significantly less during the dart-throwing motion than during either wrist flexion-extension or radioulnar deviation. CONCLUSION: If the goal of early wrist motion after carpal ligament or distal radius injury and reconstruction is to minimize loading of the healing structures, a wrist motion in which scaphoid motion is minimal should reduce length changes in associated ligamentous structures. Therefore, during rehabilitation, if a patient uses a dart-throwing motion that minimizes his or her scaphoid tuberosity excursion, there should be minimal changes in ligament loading while still allowing wrist motion. STUDY DESIGN: Bench research, biomechanics, and cross-sectional. LEVEL OF EVIDENCE: Not applicable. The study was laboratory based.

Computed tomography arthrography using a radial plane view for the detection of triangular fibrocartilage complex foveal tears.

PURPOSE: To classify triangular fibrocartilage complex (TFCC) foveal lesions on the basis of computed tomography (CT) arthrography using a radial plane view and to correlate the CT arthrography results with surgical findings. We also tested the interobserver and intra-observer reliability of the radial plane view. METHODS: A total of 33 patients with a suspected TFCC foveal tear who had undergone wrist CT arthrography and subsequent surgical exploration were enrolled. We classified the configurations of TFCC foveal lesions into 5 types on the basis of CT arthrography with the radial plane view in which the image slices rotate clockwise centered on the ulnar styloid process. Sensitivity, specificity, and positive predictive values were calculated for each type of foveal lesion in CT arthrography to detect foveal tears. We determined interobserver and intra-observer agreements using kappa statistics. We also compared accuracies with the radial plane views with those with the coronal plane views. RESULTS: Among the tear types on CT arthrography, type 3, a roundish defect at the fovea, and type 4, a large defect at the overall ulnar insertion, had high specificity and positive predictive value for the detection of foveal tears. Specificity and positive predictive values were 90% and 89% for type 3 and 100% and 100% for type 4, respectively, whereas sensitivity was 35% for type 3 and 22% for type 4. Interobserver and intra-observer agreement was substantial and almost perfect, respectively. The radial plane view identified foveal lesion of each palmar and dorsal radioulnar ligament separately, but accuracy results with the radial plane views were not statistically different from those with the coronal plane views. CONCLUSIONS: Computed tomography arthrography with a radial plane view exhibited enhanced specificity and positive predictive value when a type 3 or 4 lesion was identified in the detection of a TFCC foveal tear compared with historical controls. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.

Arthroscopic Partial Capitate Resection for Type Ia Avascular Necrosis: A Short-Term Outcome Analysis.

PURPOSE: To examine short-term clinical results of arthroscopic partial resection for type Ia avascular necrosis of the capitate. METHODS: Patients who underwent arthroscopic treatment for type 1a avascular necrosis of the capitate with at least 1-year follow-up were identified through a retrospective chart review. The necrotic capitate head was arthroscopically resected with removal of the lunate facet and preservation of the scaphoid and hamate facets. Wrist range of motion, grip strength, and radiographic parameters--carpal height ratio, radioscaphoid angle, and radiolunate angle-were determined before surgery and at the latest follow-up. Patients completed a visual analog scale for pain; Disabilities of the Arm, Shoulder, and Hand measure; and the Patient-Rated Wrist Evaluation score before surgery and at the latest follow-up. RESULTS: Five patients (1 male, 4 females) with a mean age of 34 years (range, 16-49 years) and a mean follow-up duration of 20 months (range, 12-36 months) were identified during the chart review. All were type Ia (Milliez classification). Arthroscopy revealed fibrillation or softening with cartilage detachment at the lunate facet of the capitate head and an intact articular surface at the scaphoid and hamate facet. At the latest follow-up, the mean wrist flexion-extension was 123° (vs 81° before surgery) and grip strength was 74% (vs 37% before surgery). The visual analog scale score for pain; the Disabilities of the Arm, Shoulder, and Hand score; and the Patient-Rated Wrist Evaluation score before surgery showed a significant improvement following treatment. Radiographic parameters did not significantly change at the final follow-up, although the proximal carpal row trended toward flexion. CONCLUSIONS: Arthroscopic partial resection of the capitate head was an acceptable treatment for type Ia avascular necrosis of the capitate. It provided adequate pain relief and improved the range of wrist motion and grip strength during short-term follow-up. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

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.

Pressure and tendon strain in the sixth extensor compartment of the wrist during simulated provocative maneuvers for diagnosing extensor carpi ulnaris tendinitis.

BACKGROUND: Various provocative maneuvers for diagnosing extensor carpi ulnaris (ECU) tendinitis have been reported; however, it remains unclear which maneuver is the most sensitive to detect ECU tendinitis. To clarify this, we investigated and compared the extratendinous pressure and ECU tendon strain in the sixth extensor compartment of the wrist during various provocative maneuvers for diagnosing ECU tendinitis. METHODS: Nine upper extremities from nine fresh-frozen cadavers were examined. We investigated extratendinous pressure in the ECU fibro-osseous tunnel of the distal ulna and ECU tendon strain during eight forearm positions-neutral rotation, pronation, supination, pronation with wrist flexion, supination with wrist flexion, supination with wrist extension, both hand and forearm supination, and supination with ECU full loading-to simulate provocative maneuvers reported to detect ECU tendinitis. RESULTS: Pressure was significantly higher during both hand and forearm supination (carpal supination test) and during supination with wrist extension (prayer's hand supination test) than during neutral rotation. The pressure during the carpal supination test was 3 times higher than that during the prayer's hand supination test and 27 times higher than that during the neutral position. Strain was significantly higher during the carpal supination test and during supination with ECU full loading (the ECU synergy test) than during other maneuvers. CONCLUSIONS: Both pressure and tendon strain increased most notably during the carpal supination test compared to the other maneuvers, which suggests that the carpal supination test is the most sensitive for the detection of ECU tendinitis.

International Federation of Societies for Surgery of the Hand 2013 Committee's report on wrist dart-throwing motion.

This report updates information on wrist dart-throwing (DT) motion, based on the most recent research published on the kinematics, kinetics, and clinical applications of DT motion. A wide range of DT planes exists. "Pure" DT motion is done along an oblique plane that intercepts the coronal and sagittal planes at the zero position, and occurs almost exclusively at the midcarpal joint with near zero scaphoid and lunate motion. "Functional" DT motion such as a hammering is done along an oblique plane that is almost parallel to the pure DT plane, but that has an offset toward the dorsal side. Functional DT rotation has greater scaphoid and lunate motion compared with pure DT motion. Midcarpal arthrodesis adversely affects DT motion compared with radiocarpal arthrodesis. During a DT motion, the mean and peak tendon forces of the flexor carpi ulnaris and the extensor carpi radialis longus were the greatest among wrist motors. By performing a task along the plane of DT motion, the scapholunate (SL) joint was stable and SL ligament elongation was minimal in healthy subjects. However, a more recent study of patients with SL dissociation revealed that DT exercises applied tensile forces on the SL ligament and induced an SL gap.

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

BACKGROUND: Osteochondral 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. METHODS: We 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. RESULTS: The 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. CONCLUSIONS: An 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.

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.

Radiographic clues for determining carpal instability and treatment protocol for scaphoid fractures.

The magnitude of carpal instability following scaphoid fracture is closely related to the fracture location. Middle-third fractures of the scaphoid are classified into B1 (distal oblique fractures) and B2 (complete waist fractures). Deciding preoperatively whether a fracture is B1 or B2 is clinically important, because several studies have revealed that B1 is more stable than B2. Dorsal intercalated segment instability deformity often develops in B2, creating a large, wedge-shaped bone defect, while minimal humpback deformity develops in B1, and the bone defect is much smaller, even after long-standing nonunions. However, determination of the fracture types using X-rays may be less accurate than using three dimensional computed tomography. This article suggests two radiographic clues for estimation of post-fracture carpal instability along with a treatment protocol for each fracture type.

Morphological evaluation of the distal interosseous membrane using ultrasound.

Evidence from a recent cadaveric study has revealed that the thickness of the distal interosseous membrane (DIOM) of the forearm shows substantial individual variations, and a thick fibrous tissue known as the distal oblique bundle (DOB) was found in 40% specimens in the study. Another cadaveric study revealed that greater stability of the distal radioulnar joint (DRUJ) was obtained in a group with DOB following ulnar shortening than in a group without DOB. Thus, the presence of DOB influences the condition of DIOM and the ability of DIOM to provide stability to the compromised DRUJ. In the present study, we carried out a preoperative morphological evaluation of DIOM using ultrasound (US) and compared the US findings with intraoperative findings in order to investigate the efficacy and the meanings of this US evaluation. A total of 14 patients with various diseases or injuries of the distal forearm requiring corrective surgery were enrolled. The mean values of DIOM thickness as measured by US evaluation correlated well with those measured intraoperatively. The sensitivity of US evaluation in confirming presence of DOB was 80% when the presence of DOB bundle was judged by DIOM thickness. In addition, 4 of 5 patients with chronic DRUJ instability showed no DOB. This study suggested that US can be a useful tool in evaluating DIOM and for detecting the presence of DOB and may provide helpful information regarding DRUJ instability.

Radiofrequency ablation for treatment for osteoid osteoma of the scapula using a new three-dimensional fluoroscopic navigation system.

Osteoid osteoma is a relatively common benign skeletal tumor. The traditional standard treatment has been surgical resection of the nidus. Recently, computed tomography (CT)-guided radiofrequency ablation (RFA) has gained favor as a more precise alternative due to potentially less bone destruction. However, CT-guided RFA is limited in treatment for osteoid osteoma involving complex anatomic structures such as cervical spine, pelvis, or scapula because of difficulty in approach and proximity to neurovascular structures. To solve this problem, we investigated RFA using a new real-time three-dimensional fluoroscopic navigation system. We report its technical procedure and use in a rare case of osteoid osteoma of the scapula.