Biomedical subjects

Robert Balyk

Publications and source records attributed to Robert Balyk.

3 recordsLinked to original sources

PubMed2005

Functional outcome and health-related quality of life after surgical repair of full-thickness rotator cuff tear using a mini-open technique.

BACKGROUND: Rotator cuff tear, a common shoulder injury, can lead to shoulder pain and functional loss. HYPOTHESIS: Surgical repair of full-thickness rotator cuff tears using the mini-open surgical technique will improve shoulder function and health-related quality of life. STUDY DESIGN: Cohort study. Level of evidence, 2. METHODS: Patients with a full-thickness rotator cuff tear who underwent a mini-open repair were evaluated for (1) active shoulder range of motion preoperatively, and 6 months and 12 months postoperatively and (2) health-related quality of life preoperatively, 6 months postoperatively, and annually up to 5 years postoperatively. Satisfaction with the repair and return to work status were ascertained 1 year postoperatively. A subgroup analysis of tear size and patient age was also undertaken. RESULTS: Of the subjects, 61 (73%) were men, and the average age was 53.2 ( +/- 9.9) years. According to repeated-measures analysis of variance, shoulder range of motion (flexion and external rotation) improved significantly from before surgery to 1 year after surgery (P <.001). The mean American Shoulder and Elbow Surgeons scores improved from 53.3 ( +/- 20.6) preoperatively to 90.6 ( +/- 11.7) 1 year postoperatively (P <.001). The mean Western Ontario Rotator Cuff scores also improved from 43.2 ( +/- 20.2) preoperatively to 87.2 ( +/- 14.3) 1 year postoperatively (P <.001). No differences were seen in either the American Shoulder and Elbow Surgeons scores or Western Ontario Rotator Cuff scores between the 1-year examination and the last follow-up assessment undertaken at a median of 5 years postoperatively (P >.05). Ninety-six percent of patients were satisfied or very satisfied with the results of their repair; 78% of patients who were working before surgery returned to work without modification by 1 year postoperatively. For the most part, patient age and size of tear did not influence postoperative range of motion or health-related quality of life. CONCLUSION: Mini-open rotator cuff repair led to improved shoulder function and health-related quality of life up to 5 years postoperatively.

Adult↗

PubMed2005

Repetitive pointing to remembered proprioceptive targets improves 3D hand positioning accuracy.

Repetitive pointing movements to remembered proprioceptive targets were investigated to determine whether dynamic proprioception could be used to modify the initial sensorimotor conditions associated with an active definition of the target position. Twelve blindfolded subjects used proprioception to reproduce a self-selected target position as accurately as possible. Ten repetitions for each limb were completed using overhead and scapular plane pointing tasks. A 3D optical tracking system determined hand trajectory start and endpoint positions for each repetition. These positions quantified three-dimensional pointing errors relative to the target position and the initial and preceding movement repetitions, as well as changes in movement direction and extent. Target position and cumulative start position errors were significantly greater than the corresponding preceding movement (inter-repetition) errors, and increased as the trial progressed. In contrast, hand trajectory start and endpoint inter-repetition errors decreased significantly with repeated task performance, as did movement extent, although it was consistently underestimated for each repetition. Pointing direction remained constant, except for the angle of elevation for scapular plane pointing, which consistently decreased throughout the trial. The results suggest that the initial conditions prescribed by actively defining a proprioceptive target were subsequently modified by dynamic proprioception, such that movement reproduction capability improved with repeated task performance.

Biomechanical Phenomena↗

PubMed2004

Dynamic upper limb proprioception in multidirectional shoulder instability.

The ability of subjects with multidirectional shoulder instability to use proprioception to complete a series of upper limb repositioning tasks was investigated. Twelve subjects with multidirectional instability and 12 control subjects were blindfolded and instructed to use proprioception to reproduce a self-selected target position as accurately as possible. Subjects completed 10 repetitions for each limb using three distinct upper limb movements: overhead reaching, scapular plane pointing, and humeral external rotation with abduction. A three-dimensional video motion analysis system tracked limb position and determined spatial hand position error. Subjects with multidirectional shoulder instability showed significantly greater hand position error than control subjects. No hand position error differences were found between the symptomatic and the asymptomatic limbs of subjects in the instability group. Inter-repetition error for subjects in both groups improved significantly during the first three movement cycles. These results suggest that after movement initiation, dynamic proprioception was a factor in improving hand position accuracy in both groups, but to a lesser degree in subjects with multidirectional instability. Consequently, subjects with multidirectional instability may have a reduced capacity to use proprioception to refine and control the motor output of the upper limb.

Adult↗