Takashi Masatomi

MR arthrography of elbow: evaluation of the ulnar collateral ligament of elbow

Abstract Objective. The purpose of this study was to evaluate ulnar collateral ligament (UCL) injury of the elbow in throwing athletes by MRI and MR arthrography. Design. Ten elbows of throwing athletes were examined on both plain MRI and MR saline arthrography and the injuries subsequently surgically proven. Spin-echo (SE) T1-weighted and fast SE T2-weighted coronal images were obtained. Results. The UCL was unclear in all ten cases on T1-weighted MRI. In five cases an avulsion fracture was also found on T1-weighted MRI. On T2-weighted MRI, abnormal high-intensity areas were identified in or around the UCL. On T2-weighted MR arthrography images, extracapsular high-intensity areas, which represent extracapsular leakage, were found in four of five cases with avulsion fracture. At surgery, all these four cases showed avulsion fractures with instability; the other case had a fracture but it was stable and adherent to the humerus. On T2-weighted MR arthrography images, an extracapsular high-intensity area was found in one of the five cases without avulsion fracture. At surgery this patient had a complete tear of the UCL itself. Conclusion. MR arthrography provided additional information for evaluating the degree of UCL injury.

Osteosynthesis for old, established non-union of the lateral condyle of the humerus.

In thirty elbows that had an established non-union of a fracture of the lateral humeral condyle that had occurred more than five years before, treatment consisted of one of three operations: anterior transposition of the ulnar nerve (nine patients), corrective osteotomy of the humerus and anterior transposition of the ulnar nerve (four patients), or osteosynthesis of the non-union combined with neurolysis and anterior transposition of the ulnar nerve, with or without corrective osteotomy of the humerus (seventeen patients). Of the thirty patients, fifteen had been apprehensive when using the elbow, due to lateral instability, or had had pain in the elbow. In thirteen of these fifteen patients, the non-union was treated by osteosynthesis. Afterward, the pain and apprehension disappeared, but the range of motion of the elbow decreased in all but three patients. Three patients had clicking between the humerus and radius, and the bone failed to unite in three others. Osteosynthesis is indicated for the treatment of non-union of the lateral humeral condyle only if the patient has serious pain in the elbow or apprehension when using the elbow, due to lateral instability.

Open Repair of Foveal Avulsion of the Triangular Fibrocartilage Complex and Comparison by Types of Injury Mechanism

PURPOSE Little attention has been paid to injury mechanisms of foveal avulsion of the triangular fibrocartilage complex (TFCC). The purpose of this study was to determine whether the mechanism of injury is associated with different anatomic disruptions as well as different preoperative clinical symptoms. We also evaluated the clinical results of an open repair method for foveal avulsion according to the mechanism of injury. METHODS Fifteen patients with a traumatic foveal TFCC avulsion were treated with an open repair technique. The injury mechanism was forced wrist extension in 10 patients (group E) and forced forearm rotation in 5 patients (group R). All patients in group E and 3 in group R showed positive fovea signs. Surgical and clinical findings were compared according to the 2 types of injury mechanism. RESULTS Foveal insertions of TFCC were found in surgery to be disrupted in all 15 patients. In addition, disruption of the dorsal styloid insertions of the radioulnar ligament showed a significantly greater association with group R than with group E. Clinical results showed significant postoperative improvement but were marginally different between the 2 groups. CONCLUSIONS The most common mechanism of foveal TFCC avulsions is forced wrist extension, an injury that commonly shows positive fovea signs and leaves the dorsal styloid insertion of the radioulnar ligament intact. Forced forearm rotation is the second most common injury mechanism that is more frequently associated with disruption of the dorsal styloid insertion. TYPE OF STUDY/LEVEL OF EVIDENCE Prognostic IV.

Arthroscopic debridement of the humeral capitellum for osteochondritis dissecans: radiographic and clinical outcomes.

PURPOSE Although arthroscopic debridement of the humeral capitellum is an accepted procedure for osteochondritis dissecans, some patients develop radial head enlargement or osteoarthritic lesions after the procedure. The aim of this study was to investigate the radiographic and clinical outcomes of arthroscopic debridement and consider its indications. METHODS We retrospectively evaluated 106 patients who had arthroscopic debridement between 1997 and 2007. Surgery was performed after closure of the capitellar physis. We categorized the patients into 4 groups by lesion size and by whether the proximal radial physis was open or closed. The average patient age at surgery was 15 years (range, 12-18 y), and the average follow-up period was 13 months (range, 8-46 mo). RESULTS In patients with large lesions and open proximal radial physes, radiographic and clinical outcomes were poor. Three of 4 patients developed early osteoarthritic lesions of the radiohumeral joint, secondary to radial head enlargement. Radial head resection was required in 2 of 3 patients. Conversely, osteoarthritic lesions did not occur, and we observed noteworthy improvement in elbow pain routinely after the procedure in the other 3 groups. For range of motion, clinically important changes were not observed. Overall, postoperative elbow pain was absent in 89 patients. Mild pain was present in 15 patients and moderate or severe pain in 2 patients. A total of 90 patients returned to sports at pre-injury levels. Time of return to sports varied from 1 month to 5 months (mean, 2.4 mo). CONCLUSIONS Arthroscopic debridement of the capitellum can provide excellent short-term results for the treatment of osteochondritis dissecans. However, it is contraindicated in cases with large lesions when the proximal radial physis remains open.

Residual deformity in congenital radial club hands after previous centralisation of the wrist

We used the Ilizarov method in seven patients with severe congenital radial club hands who had had previous wrist surgery, to correct residual shortening and bowing of the ulna together with recurrent wrist deformity. The mean age at operation was 6.5 years. The mean ulnar shortening was 5.3 cm and the mean angular deformity 42°. The mean length gained was 51% of the original ulna. The mean healing index was 46.9 days (29.8 to 64.0). The ratio of the length of the lengthened ulna to the normal side improved on average from 64% to 95%. The angular deformity was initially completely corrected in six out of seven patients. The length ratio, however, decreased to 83% at the final follow-up. In four patients, the angular deformity partially recurred. We recommend correction of congenital radial club hand by staged procedures. The first is centralisation and stabilisation of the wrist and the second lengthening of the ulna and correction of the angular deformity using the Ilizarov method.

In vivo and 3-dimensional functional anatomy of the anterior bundle of the medial collateral ligament of the elbow

BACKGROUND Although the anterior bundle of the medial collateral ligament (AMCL) is a critical stabilizer of the elbow joint, little information exists on in vivo and 3-dimensional functional anatomy of the AMCL. The purposes of this study were to investigate in vivo changes in the length of the AMCL during elbow flexion and to clarify the 3-dimensional functional anatomy of the AMCL. METHODS We created 3-dimensional models of the AMCL and bones from computed tomography data of 4 healthy elbows in 5 different elbow positions. The AMCL was subdivided into 9 ligaments. We calculated changes in lengths of ligaments during flexion and related ligament origins to the axis of rotation of the elbow joint. RESULTS There were 4 uniquely configured isometric ligaments, where their origins aligned broadly along the course of the axis of rotation in the coronal plane. The medially originating ligaments inserted on the posterior portion of the tubercle of the coronoid process, whereas the laterally originating ligaments inserted on its anterior portion. There were 5 non-isometric ligaments, 3 of which had origins proximal to the axis and became taut only in extension and the other 2 having origins distal to the axis and becoming taut only in flexion. CONCLUSIONS Isometric ligaments within the AMCL do not originate from a narrow area; rather, they originate from a broader area that extends more medially in the coronal plane than previously thought, which explains how the AMCL reconciles isometricity and robustness. The proximal and distal ligaments act as checkreins that work only at the limits of elbow motion.

Three-dimensional analysis of acute plastic bowing deformity of ulna in radial head dislocation or radial shaft fracture using a computerized simulation system

BACKGROUND Little 3-dimensional biomechanical investigation of plastic bowing deformity of the ulna has been reported, and the purpose of this study was to conduct such an investigation to elucidate mechanisms of injury and appropriate treatments. METHODS Ten cases of traumatic plastic deformity of the ulna in pediatric patients, 4 with chronic radial head dislocations (Monteggia equivalent) and 6 with malunited radial shaft fractures, were analyzed for rotational deformities in the axial plane and bending deformities in the sagittal and coronal planes in Euler angle space by use of a 3-dimensional computerized simulation system with a markerless registration technique. RESULTS Deformed ulnae with radial head dislocations had 18.7° ± 17.4° of external rotation in the axial plane and 10.4° ± 7.0° of extension in the sagittal plane whereas those with malunited radial shaft fractures had 12.5° ± 12.7° of internal rotation and 6.3° ± 5.6° of flexion displacement compared with mirror images of the opposite ulnae. Absolute values of rotational deformities in both groups were larger than those of sagittal and coronal bending deformities. DISCUSSION Most major traumatic plastic bowing deformities of the ulna involved rotation rather than bending. External rotational stress on the ulna is suspected to cause radial head dislocation, and internal rotational stress results in radial shaft fracture during falls onto outstretched arms. Therefore the correction of rotational deformities of the ulna should be considered in the treatment of chronic radial head dislocations and malunited radial shaft fractures.

Treatment of residual instability and extensor lag in polydactyly of the thumb.

Extensor indicis tendon transfers were used in six cases with residual deformity of the thumb in polydactyly. The indication was extensor lag and instability of the interphalangeal joint. At mean follow-up of three and a half years, normal stability was improved. Full extension was achieved in three cases and two cases also derived some benefits from this operation. Alignment was improved in five cases.

A histochemical study of the biceps brachii muscle cross-innervated by intercostal nerves 6 cases of brachial plexus injuries operated with nerve-crossing

Direct nerve-crossing of intercostal nerves from the lateral thorax to the musculocutaneous nerve was performed in 6 patients after spinal nerve root avulsion with brachial plexus palsy. Elbow flexion power was regained well enough to move against gravity and some resistance in all cases. The muscles were examined histochemically 4 (1-9) years after the operation. The intercostally-innervated biceps brachii muscle showed motor predominance of slow-twitch Type 1 fiber regeneration much more than that of fast-twitch Type 2 fiber in 5 of our patients. Our study suggests that the motor nerves of slow-twitch fibers may have priority in peripheral nerve regeneration over those of fast-twitch fibers.

Rupture of the flexor pollicis longus in von Recklinghausen's disease

An unusual cause of inability to flex the interphalangeal joint of the thumb in a patient with von Recklinghausens disease is reported. A tumor in the cubital fossa and the basic characteristics of this disease led to a preoperative misdiagnosis of anterior interosseous nerve paralysis. However, surgical exploration and histological examination showed that the correct diagnosis was rupture of the flexor pollicis longus tendon caused by intratendinous proliferation of a neurofibroma. This is the first report in the English-language literature of a flexor tendon rupture caused by intratendinous tumor proliferation.