Muneaki Abe

MORPHOLOGY AND DYNAMICS OF THE ULNAR NERVE IN THE CUBITAL TUNNEL: Observation by ultrasonography

We examined 200 normal elbows to assess the usefulness of ultrasonography in examining the ulnar nerve in the cubital tunnel. On longitudinal images in elbow extension, the nerve changed its course at the fibrous band region 11.5 (SD 2.8) mm distal to the medial epicondyle. On axial images, the diameter of the major axis of the nerve was 3.1 (0.5) mm and that of the minor axis was 1.9 (0.4) mm in men. The respective values were 2.7 (0.4) mm and 1.8 (0.4) mm in women. Dynamic studies showed that in 53 elbows (27%), the nerve moved on to the tip of the epicondyle with the elbow flexed and in 39 elbows (20%), the nerve dislocated anteriorly. The diameters of the hypermobile nerves were significantly larger than nerves that did not displace.

Excessive Humeral External Rotation Results in Increased Shoulder Laxity

Background The quantitative relationship between increased anterior shoulder laxity and increased humeral external rotation observed in throwers remains unclear. Hypothesis An elongated anterior capsule, especially the anterior band of the inferior glenohumeral ligament, produced by excessive humeral external rotation will result in increased anterior shoulder laxity and increased humeral external rotation. Study Design Controlled laboratory study. Methods Seven cadaveric shoulders were tested to measure the humeral rotational range of motion, glenohumeral translations, and length of the anterior band of the inferior glenohumeral ligament. Data were collected for the intact shoulders and after nondestructive stretching of 10%, 20%, and 30% beyond maximum humeral external rotation. Results Nondestructive excessive external rotational stretching resulted in a significant increase in superior (30%, 3.3 mm) and inferior (30%, 2.3 mm) length of the anterior band of the inferior glenohumeral ligament, external rotation (30%, 35°), and anterior (30%, 2.4 mm), inferior (30%, 2.2 mm), and anterior-posterior (30%, 5.1 mm) translations. There were significant positive linear correlations between the length of the anterior band of the inferior glenohumeral ligament, external rotation, and anterior translation. Conclusions Excessive humeral external rotation results in an elongation of the anterior band of the inferior glenohumeral ligament and an increase in anterior and inferior glenohumeral translations and humeral external rotation. Clinical Relevance Repetitive excessive humeral external rotation observed in throwers may be one of the biomechanical causes for increased shoulder laxity and increased humeral external rotation.

The dorsiflexion-eversion test for diagnosis of tarsal tunnel syndrome

Background: The clinical diagnosis of tarsal tunnel syndrome lacks objectivity and consistency. We have devised a new diagnostic physical examination test in which the tibial nerve is compressed as it runs beneath the flexor retinaculum behind the medial malleolus. In this test, the ankle is passively maximally everted and dorsiflexed while all of the metatarsophalangeal joints are maximally dorsiflexed and held in this position for five to ten seconds. Methods: We performed this test on fifty normal volunteers (100 feet) and on thirty-seven patients (forty-four feet) treated operatively for tarsal tunnel syndrome between 1987 and 1997. We performed the maneuver both preoperatively and postoperatively and recorded any consequent changes in the signs and symptoms; during the operation we observed the altered anatomical relationships in the tarsal tunnel that were produced by the maneuver. The average duration of follow-up was three years and eleven months. Results: Before the operation, the signs and symptoms of tarsal tunnel syndrome were intensified or induced by the maneuver in fifteen of the twenty feet of the patients who reported numbness, in fifteen of the seventeen feet of those who reported pain alone, and in six of the seven feet of those who had combined numbness and pain. Local tenderness was intensified in forty-two of forty-three feet, and it was induced in one foot in which it had been previously absent. A Tinel sign became more pronounced in forty-one feet, and the sign was induced in three feet in which it had been absent previously. During the operation, the tibial nerve was stretched and compressed beneath the laciniate ligament when the ankle was dorsiflexed, the heel was everted, and the toes were dorsiflexed. Preoperative signs and symptoms disappeared on an average of 2.9 months after the operation, and they could not be induced by repeating the test except in three patients, all of whom had tarsal tunnel syndrome subsequent to a fracture of the calcaneus. In the normal volunteers, no symptoms or signs could be induced by the test. Conclusion: This new physical examination test is effective in facilitating the diagnosis of tarsal tunnel syndrome.

Arthroscopic findings in chronic lateral ankle instability: do focal chondral lesions influence the results of ligament reconstruction?

Background There are few studies that have assessed the influence of focal chondral lesions on the results of ligament reconstruction for chronic lateral ankle instability. Hypothesis Focal chondral lesions do not influence the results of ligament reconstruction. Study Design Case series; Level of evidence, 4. Methods Arthroscopic examination of the ankle was performed on 30 consecutive patients immediately before ligament reconstruction using the palmaris longus tendon. Clinical assessment was performed using the Karlsson scoring scale. A radiologic assessment was performed on stress radiographs of the ankle. Preoperative anteroposterior and lateral weightbearing radiographs of the ankle did not show any joint space narrowing in any ankle. The mean duration of follow-up was 38 months. Results On arthroscopy, focal chondral lesions were found in 19 ankles (63%). Chondral lesions were located on the medial side of the tibial plafond in 13 ankles (43%), on the lateral side in 2 ankles (7%), on the lateral side of the talar dome in 3 ankles (10%), and on the medial side in 9 ankles (30%). Postoperative mean Karlsson scores in patients without chondral lesions and in those with chondral lesions were 99.1 and 98.4 points, respectively. Postoperative mean talar tilt angles in patients without chondral lesions and in those with chondral lesions were 5.9° and 4.7°, respectively. There were no significant differences in the clinical and radiologic results between patients with chondral lesions and those without chondral lesions. Conclusions Reconstruction of the lateral ligament can be successful regardless of the presence of focal chondral lesions in patients with chronic lateral ankle instability when preoperative weightbearing radiographs of the ankle do not show any joint space narrowing.

Biomechanical comparison of kyphoplasty with different bone cements.

Study Design. Ex vivo biomechanical study. Objectives. To compare the biomechanical properties of isolated, fractured, osteoporotic vertebral bodies after treatment by kyphoplasty with one of two cements: &agr;-tri-calcium phosphate cement (Biopex-R; Mitsubishi Materials Corp., Tokyo, Japan) or polymethylmethacrylate (Simplex P; Stryker-Howmedica-Osteonics, Mahwah, NJ). Summary of Background Data. Kyphoplasty and vertebroplasty typically use polymethylmethacrylate cements for the treatment of osteoporotic compression fractures. Scant information exists regarding the use of alternative cements in kyphoplasty. Methods. Simulated compression fractures were created in 24 vertebral bodies (T6–T9, L2–L5) harvested from three female cadavers. Vertebral bodies were assigned to one of two groups: kyphoplasty with Biopex-R or kyphoplasty with Simplex P. The kyphoplasty treatment consisted of inserting bone tamps bipedicularly into each vertebral body, inflating the tamp, and filling the created void with Biopex-R or Simplex P. Pretreatment and post-treatment heights were measured, and the repaired vertebral bodies were recompressed to determine posttreatment strength and stiffness values. Differences were checked for significance (P < 0.05) using a repeated-measures analysis of variance followed by Tukey’s test. Results. Kyphoplasty with Biopex-R restored strength in the lumbar and thoracic vertebral bodies. Kyphoplasty with Simplex P displayed significantly greater posttreatment strength than initial strength in the thoracic region. Vertebral bodies augmented with either cement were significantly less stiff than their initial conditions, except for the thoracic vertebrae treated with Simplex P, in which stiffness was restored. There was no significant difference in percentage of height restored between the cement treatments. Conclusions. Kyphoplasty with either cement restored initial strength. In general, stiffness was not restored.

Tardy ulnar nerve palsy caused by cubitus varus deformity

Fifteen patients with tardy ulnar nerve palsy caused by cubitus varus deformity were studied. All patients had a history of previous fracture of the humerus during childhood. The mean interval between fracture and onset of symptoms was 15 years. The severity of the palsy was classified as McGowans grade I in 12 patients, grade II in 2 patients, and grade III in 1 patient. The mean carrying angle was -2 degrees before surgery. X-ray films showed a shallow ulnar nerve groove, a dysplastic humeral trochlea, medial shift of the ulna, and deformity of the medial epicondyle. The ulnar nerve was explored in all but one patient. Operative findings suggested that the main cause of the palsy was compression by a fibrous band running between the two heads of flexor carpi ulnaris. Surgical steps included release of the fibrous band in 14 patients with anterior subcutaneous transposition of the ulnar nerve in 5 of those patients. A corrective osteotomy was done in 11 patients who requested correction of the varus deformity. Traumatic cubitus varus deformity should be recognized as another cause of cubital tunnel syndrome.

Tarsal tunnel syndrome associated with an accessory muscle.

Between 1986 and 1999, we surgically treated 41 patients (49 feet) with Tarsal Tunnel Syndrome (TTS) in whom seven (eight feet) were associated with an accessory muscle. An accessory flexor digitorum longus muscle was present in six patients, and an accessory soleus muscle was in one patient (both feet). Three of them were males and four females, with the mean age of 33.1 years (12 to 59 years). The mean interval from the onset of symptoms to operation was 7.5 months (range, six to nine months). All patients with an accessory muscle had a history of trauma or strenuous sporting activity. The diagnosis of TTS was made based on physical findings in all the patients (eight feet) and confirmed in five patients (six feet) by electrophysiological examination. Imaging examinations (radiography, ultrasonography, MRI) revealed abnormal bone and soft tissue lesions in and around the tarsal tunnel. Preoperative signs and symptoms disappeared average 4.1 months after decompression of the tibial nerve in addition to excision of the muscle. No functional deficit was observed at final follow-up (24 to 88 months).

Tarsal Tunnel Syndrome in Athletes

Background The details of the occurrence of tarsal tunnel syndrome in athletes have not been well documented in the literature, and more data on tarsal tunnel syndrome related to sporting activity are necessary to enable better recognition of this condition. Hypothesis Sporting activities make athletes vulnerable to the occurrence of tarsal tunnel syndrome under specific conditions. Study Design Case series; Level of evidence, 4. Methods Between 1986 and 2002, 18 patients with tarsal tunnel syndrome related to sporting activities were surgically treated, of whom 15 patients (21 feet; mean age, 17.8 years) were competitive athletes and 3 were recreational sports amateurs (4 feet; mean age, 52.7 years). To assess the role of physical factors and sporting activities in making athletes vulnerable to the occurrence of tarsal tunnel syndrome, the authors reviewed the medical charts and evaluated the results of treatment. The mean duration of follow-up was 58.6 months. Results Activities that triggered tarsal tunnel syndrome were those that applied a heavy burden on the ankle joint such as sprinting, jumping, and performing ashibarai in judo under specific physical conditions. Predisposing underlying physical factors were flatfoot deformity and an existence of talocalcaneal coalition, accessory muscles, and bony fragments around the tarsal tunnel. The majority of patients were able to return to the same sport after treatment. Conclusion Tarsal tunnel syndrome occurs in athletes involved in strenuous sporting activities, especially when predisposing physical factors are present.

Distal soft tissue procedure and proximal metatarsal osteotomy in hallux valgus.

The results of a distal soft tissue procedure and a proximal metatarsal osteotomy in patients with symptomatic hallux valgus deformity were reviewed. The series consisted of 33 patients (47 feet; mean age of patients, 44 years). The average followup period was 48 months. At followup, 41 feet (29 patients, 85%) were free from pain at the first metatarsophalangeal joint. In six feet (four patients), the pain was improved but persisted. The mean hallux valgus angle was 38° before surgery and 13.8° after surgery. The mean intermetatarsal angle was 17.7° before surgery and 7° after surgery. The postoperative hallux valgus angle and intermetatarsal angle in patients who had pain at the first metatarsophalangeal joint after surgery were greater than those in patients without pain after surgery. This procedure corrects the hallux valgus deformity and relieves the symptoms, but careful attention should be paid to the surgical technique to obtain consistent and satisfactory results.

Lengthening of the forearm by callus distraction

Ten patients aged 3 to 13 years (mean, 9 years and 7 months) underwent forearm lengthening by callotasis. The indications for lengthening were shortening and/or deformity of the forearm due to exostosis of the distal ulna in five cases, enchondroma of the distal ulna in one, growth disturbance after fracture of the distal radius in one, radial club hand in one, congenital amputation of the forearm in one and congenital dislocation of the radial head in one. Four had lengthening of the ulna, one of the radius and five of both the radius and the ulna. The average lengthening achieved was 30 mm. Complications encountered were pin track discharge in three cases, callus fracture in five, delayed consolidation of the callus in one and no callus formation in one. Review after 1 to 7 years follow-up (with a mean of 4 years and 9 months) showed satisfactory improvement in appearance and function especially in patients who had tumorous conditions or traumatic epiphyseal arrest.