MaryBeth Horodyski

Humeral retroversion and its relationship to glenohumeral rotation in the shoulder of college baseball players.

Background Previous studies have documented changes in musculature, bony anatomy, and glenohumeral rotation in the dominant shoulder of baseball players. Hypothesis In a group of asymptomatic college baseball players the total range of motion in the dominant and nondominant shoulders will be similar. Any measured increase in external rotation and decrease in internal rotation occurring between the two sides will be consistent and directly correlate with an increased angle of humeral retroversion in the dominant extremity. Study Design Descriptive anatomic study. Methods Fifty-four asymptomatic college baseball players were examined. Standard measurements of glenohumeral range of motion were made and humeral retroversion was determined radiologically. Results Total rotational motion, measured at 90° of glenohumeral abduction, was 159.5° for the dominant shoulders and 157.8° for the nondominant shoulders. Mean differences in external and internal rotation in the dominant versus nondominant extremities were 9.7° and 8.2°, respectively. Humeral retroversion measured 36.6° ± 9.8° in the dominant and 26° ± 9.4° in the nondominant extremity. The mean difference in retroversion correlated significantly by Pearsons product moment with the difference in external (P = 0.001) and internal (P = 0.003) rotation measurements. Conclusions There is a pattern of increased external rotation and decreased internal rotation in the dominant extremity that significantly correlates with an increase in humeral retroversion. The loss of internal rotation and gains in external rotation may be more strongly related to adaptive changes in proximal humeral anatomy than to changes in the soft tissues.

Rotational Motion Changes in the Glenohumeral Joint of the Adolescent/Little League Baseball Player

Background Differences in range of motion and rotational motion between the dominant and nondominant shoulders in throwing athletes are well documented, although the age at which these changes begin to occur is not known. Hypothesis Changes in glenohumeral rotational motion in the shoulder of the Little League/adolescent baseball player occur during the most formative years of physical development. Study Design Cross-sectional study. Methods Elevation, internal rotation at 90° of abduction, and external rotation at 90° of abduction were measured in the dominant and nondominant shoulders of 294 baseball players, aged 8 to 16 years. Results Analysis of variance revealed 2-way interactions between arm dominance by age for elevation (P =. 005) and internal rotation (P =. 001). Significant differences were noted between dominant and nondominant arms for internal rotation at 90° (P =.001) and external rotation at 90° (P =. 001). Elevation, internal rotation at 90°, external rotation at 90°, and total range of motion varied significantly (P =. 001) among age groups. Elevation in the dominant arms of 16-year-olds was on average 5.3° less than in 8-year-olds (179.6° vs 174.3°). In the nondominant arms, mean elevation for 16-year-olds was 5.6° less than in 8-year-olds (179.7° vs 174.1°). Internal rotation at 90° for the dominant arms averaged 39.0° at age 8 and only 21.3° at age 16. In the non-dominant arms, internal rotation for 8-year-olds averaged 42.2° and only 33.1° for 16-year-olds. Conclusions Elevation and total range of motion decreased as age increased. These changes may be consequences of both bone and soft tissue adaptation. The most dramatic decline in total range of motion was seen between the 13-year-olds and 14-year-olds, in the year before peak incidence of Little Leaguers shoulder. This decrease in rotational motion may cause increased stress at the physis during throwing.

Nonirradiated Versus Irradiated Achilles Allograft In Vivo Failure Comparison

Background Many studies suggest that gamma irradiation decreases allograft strength in a dose-dependent manner. No study has demonstrated that this decrease in strength translates into higher clinical failures. Hypothesis Irradiation of allograft tissue will lead to higher early clinical failure in anterior cruciate ligament (ACL) reconstruction. Study Design Cohort study; Level of evidence, 3. Methods Medical records were reviewed for 90 consecutive patients who had received Achilles allograft reconstruction for unilateral primary ACL injuries at one institution between July 2001 and June 2002. One half of patients received nonirradiated Achilles allograft and the other half received irradiated Achilles allograft at a dose range of 2.0 to 2.5 Mrad. The ACL allograft reconstructions were performed using the same surgical technique. The rehabilitation program was identical for both groups. All clinical failures were recorded. Results At least 6 months’ follow-up was available on 42 subjects in the nonirradiated group and 33 subjects in the irradiated group. A significant difference was noted in early failure rates between the groups (P < .01). The nonirradiated group had 1 in 42 (2.4%) catastrophic failure. In the irradiated group, 11 of 33 (33%) Achilles tendon grafts failed. Conclusions Less than satisfactory results led the senior authors to discontinue the use of irradiated allografts in ACL surgery. Continued research into alternatives to gamma irradiation is needed.

National Athletic Trainers' Association Position Statement: Acute Management of the Cervical Spine- Injured Athlete

OBJECTIVE To provide certified athletic trainers, team physicians, emergency responders, and other health care professionals with recommendations on how to best manage a catastrophic cervical spine injury in the athlete. BACKGROUND The relative incidence of catastrophic cervical spine injury in sports is low compared with other injuries. However, cervical spine injuries necessitate delicate and precise management, often involving the combined efforts of a variety of health care providers. The outcome of a catastrophic cervical spine injury depends on the efficiency of this management process and the timeliness of transfer to a controlled environment for diagnosis and treatment. RECOMMENDATIONS Recommendations are based on current evidence pertaining to prevention strategies to reduce the incidence of cervical spine injuries in sport; emergency planning and preparation to increase management efficiency; maintaining or creating neutral alignment in the cervical spine; accessing and maintaining the airway; stabilizing and transferring the athlete with a suspected cervical spine injury; managing the athlete participating in an equipment-laden sport, such as football, hockey, or lacrosse; and considerations in the emergency department.

Assessment of Shoulder Proprioception in the Female Softball Athlete

Background There have been reports of overhand throwing athletes having decreased joint position sense in their dominant shoulder as compared with the nondominant shoulder. Very little research, however, exists concerning joint position sense in the female athlete. Hypothesis Female softball athletes have decreased joint position sense in their dominant shoulder as compared with their nondominant shoulder. Study Design Factorial design with investigation of multiple independent variables. Methods Joint position sense was assessed in 50 female softball players and 50 nonthrowing female athletes by using an inclinometer during four glenohumeral joint motions. Both the dominant and nondominant shoulders were assessed and error scores were calculated to describe joint position sense. Data were collected during the course of a fall semester and analyzed by using a mixed model analysis of variance with repeated measures on the dependent variable (error scores). Results A significant group by movement interaction was observed, with the softball athletes demonstrating significantly greater external rotation error scores than the nonthrowing athletes. Conclusion We failed to reject the null hypothesis. Increased error scores (less joint position sense) were observed in both arms of subjects in the softball group. Clinical Relevance This study suggests that there is decreased shoulder proprioception in asymptomatic female athletes involved in overyhand throwing sports, which may predispose them to injury.

Spine-board Transfer Techniques and the Unstable Cervical Spine

Study Design. A repeated-measures design using a cadaveric model was used in this preliminary investigation on the effectiveness of spine-board transfer techniques. Objectives. To compare the amount of angulation (flexion–extension) motion that results at the cervical spine during the execution of the log-roll maneuver and the lift-and-slide technique; and to examine how changes to the integrity of the cervical spine impacts the amount of motion generated during the transfer process. Summary of Background Data. Very little research has been performed to establish the efficacy of spine-board transfer techniques. Early studies have indicated that the log-roll maneuver may not be appropriate for transferring victims with thoracolumbar injuries. Also, there has not been a single study that has reported the impact of transfer techniques on the unstable cervical spine. This lack of data necessitated the present study. Methods. Four groups (with six participants each) were asked to execute the log-roll maneuver and the lift-and-slide technique on five cadavers. An electromagnetic motion analysis device was used to assess the amount of angulation motion generated at the C5–C6 segment during the execution of these transfer techniques. To examine how changes to the integrity of the cervical spine impacts the amount of motion that is produced during the transfer process, flexion–extension motion was assessed under various conditions: across a stable C5–C6 segment, after the creation of a posterior ligamentous injury, and after a complete segmental injury. Results. No significant differences in angulation motion were noted between transfer techniques. However, significant differences were noted between all three injury conditions. That is, as the severity of the injury increased, the average amount of angulation motion produced at the site of the lesion also increased, regardless of technique. Conclusion. The participants of this study were able to restrict flexion–extension motion equally well with thelog-roll maneuver as with the lift-and-slide technique. However, more research is needed to fully ascertain the effectiveness of spine-board transfer techniques.

Functional outcome of surgically treated massive rotator cuff tears: a comparison of complete repair, partial repair, and debridement.

Functional outcomes of three surgical treatments for massive rotator cuff repairs were compared. Surgery was performed by a single surgeon (T.W.W.) on 38 patients (mean age: 62.5 years). The surgeon decided which procedure to use for each patient based on tissue quality, ability to mobilize the torn rotator cuff, and degree of tension after the repair was attempted. Twenty-one patients underwent complete repair, 11 underwent partial repair, and 6 had debridement alone. Results were evaluated using the Shoulder Pain and Disability Index and by measuring range of motion and strength. The mean Shoulder Pain and Disability Index score for all patients postoperatively was 25, with subindices averaging 10 for pain and 15 for function. For the subgroups, Shoulder Pain and Disability Index scores for pain and function, were 8 and 10 for complete repair, 11 and 19 for partial repair, and 14 and 24 for debridement alone, respectively. Active external rotation was significantly better (P = .008) postoperatively in patients who had a complete repair compared to debridement alone.

Cervical Collars are Insufficient for Immobilizing an Unstable Cervical Spine Injury

BACKGROUND Cervical orthoses are commonly used for extrication, transportation, and definitive immobilization for cervical trauma patients. Various designs have been tested frequently in young, healthy individuals. To date, no one has reported the effectiveness of collar immobilization in the presence of an unstable mid-cervical spine. STUDY OBJECTIVES To determine the extent to which cervical orthoses immobilize the cervical spine in a cadaveric model with and without a spinal instability. METHODS This study used a repeated-measures design to quantify motion on multiple axes. Five lightly embalmed cadavers with no history of cervical pathology were used. An electromagnetic motion-tracking system captured segmental motion at C5-C6 while the spine was maneuvered through the range of motion in each plane. Testing was carried out in intact conditions after a global instability was created at C5-C6. Three collar conditions were tested: a one-piece extraction collar (Ambu Inc., Linthicum, MD), a two-piece collar (Aspen Sierra, Aspen Medical Products, Irvine, CA), and no collar. Gardner-Wells tongs were affixed to the skull and used to apply motion in flexion-extension, lateral bending, and rotation. Statistical analysis was carried out to evaluate the conditions: collar use by instability (3 × 2). RESULTS Neither the one- nor the two-piece collar was effective at significantly reducing segmental motion in the stable or unstable condition. There was dramatically more motion in the unstable state, as would be expected. CONCLUSION Although using a cervical collar is better than no immobilization, collars do not effectively reduce motion in an unstable cervical spine cadaver model. Further study is needed to develop other immobilization techniques that will adequately immobilize an injured, unstable cervical spine.

The 6-Plus-Person Lift Transfer Technique Compared With Other Methods of Spine Boarding

CONTEXT To achieve full spinal immobilization during on-the-field management of an actual or potential spinal injury, rescuers transfer and secure patients to a long spine board. Several techniques can be used to facilitate this patient transfer. OBJECTIVE To compare spinal segment motion of cadavers during the execution of the 6-plus-person (6+) lift, lift-and-slide (LS), and logroll (LR) spine-board transfer techniques. DESIGN Crossover study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Eight medical professionals (1 woman, 7 men) with 5 to 32 years of experience were enlisted to help carry out the transfer techniques. In addition, test conditions were performed on 5 fresh cadavers (3 males, 2 females) with a mean age of 86.2 +/- 11.4 years. MAIN OUTCOMES MEASURE(S) Three-dimensional angular and linear motions initially were recorded during execution of transfer techniques, initially using cadavers with intact spines and then after C5-C6 spinal segment destabilization. The mean maximal linear displacement and angular motion obtained and calculated from the 3 trials for each test condition were included in the statistical analysis. RESULTS Flexion-extension angular motion, as well as anteroposterior and distraction-compression linear motion, did not vary between the LR and either the 6+ lift or LS. Compared with the execution of the 6+ lift and LS, the execution of the LR generated significantly more axial rotation (P = .008 and .001, respectively), more lateral flexion (P = .005 and .003, respectively), and more medial-lateral translation (P = .003 and .004, respectively). CONCLUSIONS A small amount of spinal motion is inevitable when executing spine-board transfer techniques; however, the execution of the 6+ lift or LS appears to minimize the extent of motion generated across a globally unstable spinal segment.

Biomechanical evaluation of the pullout strength of cervical screws.

Objective: In the process of anterior cervical fusion, little is known about the biomechanics of anterior cervical screw pullout. In this study, three different aspects of cervical screw fixation were evaluated: self-tapping (ST) versus self-drilling (SD) screws, the effect of screw geometry (length, diameter, thread pitch), and the use of rescue screws. Methods: Nine screws consisting of different diameters, lengths, and thread pitch (cancellous and cortical) were tested in peak pullout force in an artificial bone model using an MTS 858 Mini Bionix test system. Rescue screws (4.5 mm) were then inserted in the failed holes of 4.0-mm screws and extracted to determine their holding strength. Results: Length of screws and thread pitch both had a significant effect on the pullout force. Each 1 mm of increased screw length translates to 16 N of increased force to pullout in the foam bone model. Pullout strength did not vary significantly according to screw diameter or between SD and ST screws. However, the SD screw has an advantage because it can decrease the length of surgery. A decrease in pullout force of between 43% and 70% was found when using rescue screws. Conclusions: In situations in which the use of rescue/salvage screws is required, the surgeon should anticipate a significant decrease in the holding force compared with the original screw. Future directions for research include an evaluation of pullout force for screw and plate constructs.