Visuomotor Prediction Errors Modulate EEG Activity Over Parietal Cortex.

The parietal cortex is thought to be involved in visuomotor adaptation, yet it remains unclear whether it is specifically modulated by visuomotor prediction errors (i.e. PEs; mismatch between the predicted and actual visual consequences of the movement). One reason for this is that PEs tend to be associated with task errors, as well as changes in motor output and visual input, making them difficult to isolate. Here this issue is addressed using electroencephalography. A strategy (STR) condition, in which participants were instructed on how to counter a 45° visuomotor rotation, was compared to a condition in which participants had adapted to the rotation (POST). Both conditions were matched for task errors and movement kinematics, with the only difference being the presence of PEs in STR. Results revealed strong parietal modulations in current source density and low theta (2-4 Hz) power shortly after movement onset in STR vs. POST, followed by increased alpha/low beta (8-18 Hz) power during much of the post-movement period. Given recent evidence showing that feedforward and feedback information is respectively carried by theta and alpha/beta oscillations, the observed power modulations may reflect the bottom-up propagation of PEs and the top-down revision of predictions.

Arthroscopic treatment of instability attributable to capsular injury or laxity.

Among the many causes of shoulder instability are traumatic capsular injury associated with the Bankart lesion and capsular laxity as seen in multidirectional instability. Previously, open surgical procedures were the most commonly accepted surgical treatment of these disorders. However, because of the foresight of surgeons such as Richard Caspari, arthroscopy rapidly is becoming the surgical treatment of choice. Current studies have shown a 97% satisfactory outcome of arthroscopic Bankart repair. Similarly, the arthroscopic treatment of multidirectional instability has produced a 93% satisfactory outcome. These results parallel the gold standard open surgical techniques of the past and subsequently have led to a change in the treatment of shoulder instability.

Rotator cuff repairs in patients 62 years of age or older.

We retrospectively reviewed 105 consecutive patients aged 62 years and older who had undergone a repair of a rotator cuff tear to evaluate the efficacy of this surgery in patients in this age range. Six patients died, and 7 had less than 2 years of follow-up or were incapable of returning for examination. Ninety-two patients with 97 rotator cuff tears were re-examined. The average preoperative UCLA (University of California, Los Angeles) score was 12.9 (range 8 to 20), and the average postoperative score was 32.4 (range 12 to 35). Five patients (5%) had failure of the repair, accounting for the poor results. Severe complications included infection (1 patient) and brachial plexus stretch injury (1 patient). Four additional patients sustained minor complications, for an overall rate of 6%. Overall, 87% of patients had good or excellent results. Eight additional patients, while satisfied, were classified as fair. Of the 5 failures, 3 were revised to a satisfactory result. Thus 90 of the 92 patients in the study were satisfied with the result of the surgery at final follow-up. Rotator cuff repair in patients 62 years and older results in increased function, decreased pain, and satisfactory results.

Osteochondritis dissecans of the elbow.

Osteochondritis dissecans of the elbow remains a difficult problem to manage in the young athlete. Though the etiology is unclear, a definite association between overuse with repetitive microtraumatic insult and OCD has been established. Early detection and appropriate treatment can provide the best chance for preventing an unfavorable outcome. In many cases, conservative treatment regimens will provide complete resolution of symptoms, return of function, and full recovery, including return to sports participation. Surgical indications should be recognized, however, and surgical management carried out when warranted. Most authors treat unstable lesions primarily by excision of the fragment, accompanied by drilling or burring of the base of the lesion. Symptoms usually improve significantly, but approximately half of all patients will continue to experience chronic pain or limitation of elbow motion, highlighting the significance and severity of OCD of the elbow.

Arthrofibrosis and complications in arthroscopy of the elbow.

The authors offer concise procedural advice for arthroscopic treatment of flexion contractures of the elbow, bracketed by indications for treatment and recommendations regarding postoperative complications.

Arthroscopic capsulodesis of the lunotriquetral joint.

A case series consisting of 20 consecutive patients with persistent ulnar-sided mechanical wrist pain, lunotriquetral interosseous (LTIOL) ligament tears resulting in joint incongruity and increased laxity, and traumatic triangular fibrocartilage complex (TFCC) tears was reviewed. Each patient underwent an arthroscopic reduction and internal fixation (ARIF) of the lunotriquetral joint, arthroscopic disk-carpal (disklunate-ulnocapitate-disktriquetral, DL-UC-DT) ligament plication, and TFCC repair or débridement. There were 12 right wrists and 8 left wrists, of which 12 were dominant. The mean patient age was 33 years; 7 patients had workers' compensation claims and 2 had legal claims. Fourteen patients recalled a specific injury mechanism, such as hyperextension or rotation. The accompanying traumatic TFCC tears were peripheral in 15 and linear radial in 6 patients (one patient had concomitant peripheral and radial linear tears), and in 6 cases, the palmar ulnocarpal extrinsic ligaments were partially torn. The mean preoperative modified Mayo Wrist Score was 50, and at a mean of 3.1 years after surgery, the score had increased to 88. There were 13 excellent, 5 good, and 2 fair results. Four patients had complications, including transient tenderness along the extensor carpi ulnaris and persistent neuritis of a dorsal branch of the ulnar nerve. Overall wrist comfort and function, as indicated by the modified Mayo Wrist Scores, improved after arthroscopic stabilization of ulnar-sided wrist injuries (pinning of the lunotriquetral joint, disk-carpal ligament plication, and TFCC repair or débridement).

Posterolateral rotatory instability of the elbow.

Since its original description by O'Driscoll in 1991, PLRI is becoming increasingly recognized as a significant cause of elbow pathology. It is well documented that this problem results from an insufficiency of the radial ulnohumeral ligament and its related lateral structures, and that this insufficiency is usually the result of elbow trauma. Diagnosis has improved with the introduction of the PLRI test to identify the instability and advancing MR imaging capabilities of illustrating the injury. Whereas open reconstruction was previously the only definitive treatment, improving arthroscopic techniques provide a satisfactory alternative in stabilizing the elbow.

Arthroscopic repair of partial-thickness tears of the rotator cuff.

Management of partial-thickness tears of the rotator cuff should include consideration of tear size, tear depth, patient age and activity level, and tear etiology. We present an arthroscopic technique for repair of articular surface partial-thickness tears that may promote healing by closing the tendon side-to-side, placing the debrided tendon end in contact with an abraded humeral surface. By repairing selected partial-thickness tears, progression of the tear and the need for subsequent repair may be prevented. Our preliminary results in 28 patients are encouraging and suggest that this technique is a useful adjunct to tendon debridement for articular surface partial-thickness tears of the rotator cuff.

Laser-assisted capsulorrhaphy for multidirectional instability of the shoulder.

PURPOSE: The purpose of this study was to review the clinical results of laser-assisted capsulorrhaphy performed on 27 shoulders in 26 patients for multidirectional shoulder instability with minimum follow-up of 2 years. TYPE OF STUDY: Prospective case series. METHODS: Laser shrinkage was performed on the entire capsule. In patients in whom the rotator interval did not shrink, suture plication of this area was performed. All patients were evaluated with respect to the incidence of recurrent instability, need for reoperation, and ability to return to their previous level of activity or sports participation. In addition, all patients were rated as satisfactory or unsatisfactory using criteria established by Neer. RESULTS: Twenty-six of 27 shoulders (96%) remained stable and asymptomatic a minimum of 2 years after surgery. Of 14 athletes in the study group, 12 (86%) returned to their previous level of sports participation. CONCLUSION: Our results suggest that laser-assisted capsulorrhaphy is an effective treatment alternative for multidirectional instability.

Anterior superior instability with rotator cuff tearing: SLAC lesion.

Anterosuperior instability of the shoulder may occur from a variety of pathologic lesions. We describe a specific entity, the SLAC (superior labrum, anterior cuff) lesion that involves an association of anterior-superior labral tear with a partial supraspinatus tear. We retrospectively isolated a group of 40 patients with this lesion. The presenting complaints, physical examination findings, surgical findings, and results were isolated. Overhead activities were the most common etiology; load and shift instability testing and whipple rotator cuff testing were the most common physical examination findings. Surgical repair was successful in 37 of the 40 patients. The SLAC lesion is a definable clinical entity with predictable history, examination, surgical pathology, and satisfactory results from surgery.