Faculty Bibliography

VO ₂ max is a measure of athletic performance and is generally considered an excellent health parameter for athletic performance testing. Various methods are used to generate such a result generally using a treadmill or cycle ergometer. Improvements have been shown through training. The upper limit of such improvement has been difficult to find in the literature in part because testing often starts with individuals already at a superior level of performance. As genetics may play a significant role in an individual's VO ₂ max, training can only contribute a portion of the result. Humans have a range of maximal oxygen utilization with upper limits approaching 100 mL/kg. This case report demonstrates a 96% improvement over time secondary to selective intense training. The intent was to document objectively amelioration of the VO ₂ max using a defined protocol on standardized testing equipment. This may lead to more efficient training of individuals desiring performance improvement.

PURPOSE/OBJECTIVE:The purpose of this study was to describe the anatomic footprint of the subscapularis tendon. METHODS:We examined 19 cadaveric shoulder specimens in this study. Dissection was carried out to the level of the subscapularis through a deltopectoral approach. The subscapularis tendon was identified, and the dissection was continued, elevating the tendon, subperiosteally, from its insertion site at the lesser tuberosity. The dimensions of the footprint were measured superior to inferior, as well as medial to lateral, by a single observer. RESULTS:The insertion of the subscapularis tendon on the lesser tuberosity was trapezoidal in shape. The mean length of the subscapularis tendon footprint was 2.5 cm (range, 1.5 to 3.0 cm). The superior portion of the footprint was the widest part of the subscapularis insertion. The mean width at the most superior aspect of the insertion site was 1.8 cm (range, 1.5 to 2.6 cm). The most inferior aspect of the footprint was much narrower, with a mean width of 0.3 cm (range, 0.1 to 0.7 cm). CONCLUSIONS:The subscapularis insertion footprint has a broad and wide superior attachment that narrows distally to form a trapezoidal shape. We found the mean length of the footprint to be 2.5 cm. The mean superior width of the footprint was 1.8 cm, which was maintained for the upper 60% of the tendon insertion, at which point the footprint began to rapidly narrow to a minimum width of 0.3 cm at its most inferior aspect. The upper 60% of the footprint provided by far the major surface area for tendon insertion, consistent with prior findings of superior load transmission at the superior aspect of the footprint. CLINICAL RELEVANCE/CONCLUSIONS:This broad attachment site superiorly is likely important in load transmission. Knowledge of the shape of the footprint of the subscapularis, with a broad superior attachment, makes it easier for the surgeon to perform an accurate anatomic surgical reconstruction of the torn subscapularis.

PURPOSE/OBJECTIVE:Our objective was to evaluate the preliminary results of 25 consecutive arthroscopic subscapularis tendon repairs. TYPE OF STUDY/METHODS:Case series. METHODS:All 25 shoulders had longer than 3 months follow-up, with an average of 10.7 months (range, 3 to 48 months). The average age was 60.7 years (range, 41 to 78 years). The average time from onset of symptoms to surgery was 18.9 months (range, 1 to 72 months). The shoulders were evaluated using a modified UCLA score, Napoleon test, lift-off test, radiographs, and magnetic resonance imaging (MRI). Indications for surgery included clinical and/or MRI evidence of a rotator cuff tear. An arthroscopic suture anchor technique devised by the senior author (S.S.B.) was used for repair. RESULTS:UCLA scores increased from a preoperative average of 10.7 to a postoperative average of 30.5 (P <.0001). By UCLA criteria, excellent and good results were obtained in 92% of patients, with 1 fair and 1 poor result. Forward flexion increased from an average 96.3 degrees preoperatively to an average 146.1 degrees postoperatively (P =.0016). Eight of 9 patients with a positive Napoleon test had complete tears of the subscapularis. All 7 patients with a negative Napoleon test had a tear of the upper half only. The lift-off test could not be performed reliably due to pain or restricted motion in 19 of the 25 patients. Eight patients had isolated tears of the subscapularis. The remaining 17 patients had associated rotator cuff tears with an average total tear size of 5 x 8 cm. Ten patients had proximal migration of the humerus preoperatively. Eight of these 10 patients had durable reversal of proximal humeral migration following surgery. These 8 patients improved their overhead function from a preoperative "shoulder shrug" with attempted elevation of the arm to functional overhead use of the arm postoperatively. CONCLUSIONS:(1) The senior author has been able to consistently perform arthroscopic repair of torn subscapularis tendons, with good and excellent results, in 92% of patients. (2) The Napoleon test is useful in predicting not only the presence of a subscapularis tear, but also its general size. (3) Combined tears of the subscapularis, supraspinatus, and infraspinatus tendons are frequently associated with proximal humeral migration and loss of overhead function. Arthroscopic repair of these massive tears can produce durable reversal of proximal humeral migration and restoration of overhead function.

PURPOSE/OBJECTIVE:Our goal was to establish a consistent methodology for quantifying glenoid bone loss by arthroscopic means. TYPE OF STUDY/METHODS:This study was an anatomic investigation of glenoid structure and its consistent anatomic landmarks as determined by arthroscopic means in live subjects and by direct measurement in fresh-frozen cadaver specimens. METHODS:We arthroscopically evaluated and measured the location of the bare spot of the glenoid in 56 subjects that had no evidence of instability (average age, 40 years). We also measured the exact location of the glenoid bare spot in 10 cadaver shoulders (average age, 76 years). RESULTS:The bare spot of the glenoid was a consistent reference point from which to determine glenoid bone loss because it was located almost exactly at the center of the circle that was defined by the articular margin of the inferior glenoid below the level of the midglenoid notch. The tightly clustered standard deviations of the bare spot measurements in both the live subjects and the cadaver specimens confirmed its consistent location. CONCLUSIONS:The glenoid bare spot can be used as a central reference point to quantify the percentage bone loss of the inferior glenoid. Such objective measurement of glenoid bone loss can be clinically useful to the surgeon in deciding whether bone grafting is necessary to restore stability to the shoulder with a bone-deficient glenoid.

We present a case of transient quadriparesis in an 8-yr-old football player with a normal cervical spinal canal but Chiari I malformation of the hindbrain. Chiari I consists of herniation of the cerebellar tonsils through the foramen magnum, which reduces space available for the spinal cord. Magnetic resonance imaging (MRI) of the brain or cervical spine can identify asymptomatic Chiari I, whereas previously myelography was necessary. The incidence and natural history of Chiari I malformation is reviewed, with special reference to the question of return-to-play in young athletes.

The effects of misoprostol, a prostaglandin E1 analog, and prostaglandin E2 on proteoglycan biosynthesis and loss were studied in unloaded and mechanically loaded mature bovine articular cartilage explants. The prostaglandins were administered daily at dosages of 0, 10, 100 and 1000 eta g/ml for up to seven days, and proteoglycan biosynthesis determined by measurement of radiolabelled sulfate incorporation. The presence of misoprostol lead to a significant (p < 0.001) dose-dependent inhibition (30%-50%) in proteoglycan biosynthesis which was also dependent on exposure time (p < 0.05). A significant decrease in biosynthesis (34%) was also found for prostaglandin E2, but only at the highest dose (1000 eta g/ml). Proteoglycan catabolism rates were not affected by either substance as assessed by loss of newly synthesized proteoglycan. The application of a continuous cyclic mechanical compressive load (stress of 1.0 MPa at 1 hertz for 24 hours) resulted in a significant inhibition of proteoglycan biosynthesis (up to 50%) as compared to unloaded explants. However, there was no additive effect when mechanical load and misoprostol or prostaglandin E2 were combined. These results suggest that prostaglandins may have a role in the degenerative and repair process in various forms of arthritis where elevated intra-articular levels of prostaglandin E2 are present.