ABSTRACT
BACKGROUND: The glenohumeral internal rotation deficit (GIRD) is diagnosed when there is a loss of 20° of internal rotation compared to the contralateral shoulder. This condition has already been well described in a group of throwing athletes, i.e. baseball pitchers. However, athletic athletes such as javelin throwers, discus throwers, hammer throwers, shot putters may also be susceptible to this condition. Reports are lacking to recognize these symptoms as GIRD for these group of athletes. We aim to evaluate these subgroups of athletes for the possibility of GIRD. MATERIALS AND METHODS: We examined ten athletes (javelin, hammer throwers, and shot putters) for signs of GIRD. Signs of loss of internal rotation were assessed by measuring shoulder range of motion (internal rotation and external rotation) in supine position and posterior shoulder tightness test. Complaints of shoulder pain, evidence of scapular malposition, inferior medial border prominence, coracoid pain and malposition, and dyskinesis of scapular movement (SICK) scapula, posterior shoulder flexibility test were examined. RESULTS: The athletes had a mean training period of 3.8 years. One athlete had complaints of mild pain on their dominant shoulder. Two athletes had GIRD (20° and 25°) with no posterior shoulder tightness. Three athletes had posterior shoulder tightness, but normal total shoulder ROM (195°, 180°, and 185°). Three athletes had increased external rotation (105°, 100°, 125°). No subjects had scapular dyskinesia nor SICK scapula syndrome. All athletes had normal total shoulder ROM. CONCLUSION: Glenohumeral internal rotation deficit could be present in non-pitcher overhead athletics athletes.
ABSTRACT
BACKGROUND: Posterior instrumentation of the spine presents a challenge, especially in conditions with low bone quality. Pedicle screw insertion with cortical bone trajectory is designed to add interface between the screw and the bone through engagement between pedicles and the cortex when compared to conventional screw course. Pedicle screw insertion trajectory from cortical infero-superior and the proposed cortical supero-inferior should obtain better pull-out performance than conventional pedicle trajectory. We aim to evaluate the pull-out strength differences among conventional pedicle screw, cortical infero-superior, and cortical supero-inferior trajectories. METHODS: Samples from Yorkshire porcine lumbar spine (L1-L5; n = 30) were relieved of soft tissue attachments and dried. Morphometric measurements were conducted, and the samples were randomly assigned to 3 groups. The screws were inserted into the vertebrae by drilling with the 3 trajectories: conventional, cortical infero-superior, and cortical supero-inferior. The trajectories of the screws were examined using x-rays. Pull-out tests were conducted by applying uniaxial traction in line with the screw trajectory with a translational speed of 5 mm/min. The results of the pull-out are measured in Newtons. RESULTS: We obtained a mean value of pull-out force in conventional trajectory of 491.72 ± 187.2 N, cortical infero-superior of 822.16 ± 295.73 N, and cortical supero-inferior of 644.14 ± 201.97 N. Cortical infero-superior and cortical supero-inferior trajectories attained 67% and 30% higher pull-out mean, respectively. Using 1-way analysis of variance and a post hoc Tukey test revealed a significant difference between cortical infero-superior and conventional trajectories (P < .01). Differing pull-out strengths between cortical infero-superior and supero-inferior trajectories showed no statistical significance. Results of our study showed a 30% higher pull-out strength in our proposed trajectory than the conventional one, although not statistically significant. CONCLUSIONS: The trajectory of the screws within the lumbar spine seemed to have an impact in pull-out strength. Cortical bone engagement using the novel trajectories may increase pull-out strength of pedicle screws. LEVEL OF EVIDENCE: Level 5.
