Excessive External Rotation Research Articles

A Test for Knee Posterolateral Rotatory Instability

A test for knee posterolateral instability, which is a modification of the standard posterolateral rotatory instability test, is described. In this test, the patient lies supine on the examination table with hips and knees flexed to 90 degrees. The examiner grasps both feet and attempts to maximally externally rotate them. A positive test is indicated by (1) excessive external rotation of the affected tibia, which is easily recognized since the feet act as pointers and amplify the external rotation, and (2) a slight posterior sag of the affected tibial tubercle, which is more subtle but still a very recognizable sign.

Patterns of flexibility, laxity, and strength in normal shoulders and shoulders with instability and impingement

Imbalance of the internal and external rotator musculature of the shoulder, excess capsular laxity, and loss of capsular flexibility, have all been implicated as etiologic factors in glenohumeral instability and impingement syndrome; however, these assertions are based largely on qualitative clinical observations. In order to quantitatively define the requirements of adequate protective synergy of the internal and external rotator musculature, as well as the primary capsulolabral restraints, we prospectively evaluated 53 subjects: 15 asymptomatic volunteers, 28 patients with glenohumeral instability, and 10 patients with impingement syndrome. Range of motion was evaluated by goniometric technique in all patients with glenohumeral instability and impingement. Laxity assessment was performed and anterior, posterior, and inferior humeral head translation was graded on a scale of 0 to 3+. Isokinetic strength assessment was performed in a modified abducted position using the Biodex Clinical Data Station with test speeds of 90 and 180 deg/sec. Internal and external rotator ratios and internal and external rotator strength deficits were calculated for both peak torque and total work. Patients with impingement demonstrated marked limitation of shoulder motion and minimal laxity on drawer testing. Both anterior and multidirectional instability patients had excessive external rotation as well as increased capsular laxity in all directions. Sixty-eight percent of the patients with instability had significant impingement signs in addition to apprehension and capsular laxity. Isokinetic testing of asymptomatic subjects demonstrated a 30% greater internal rotator strength in the dominant shoulder. Comparison of all three experimental groups demonstrated a significant difference between internal and external rotator ratios for both peak torque and total work. Conclusions are that there appears to be a dominance tendency with regard to internal rotator strength in asymptomatic individuals. Impingement syndrome and anterior instability have significant differences in both strength patterns of the rotator muscles and flexibility and laxity of the shoulder. Isokinetic testing potentially may be helpful in diagnostically differentiating between these two groups in cases where there is clinical overlap of signs and symptoms.

A Functional Analysis of Shoulder Fusions

Seventeen shoulder fusions with relatively normal musculature were analyzed with particular interest to the ability of the fused extremity to perform activities of daily living. Joints fused for paralysis were excluded. No patient was able to work overhead or with arms abducted as required for activities such as hammering, house painting, or climbing a ladder. Many patients had difficulty functioning at head level for hygienic purposes. Many were unable to perform functions behind the back, although waist-level function approached normal. The position of rotation was the most critical factor in approaching optimum function. Fusions in positions of internal rotation reduced the ability to comb hair, wash the face, or to otherwise use the hand at head level. Fusion in a position of excessive external rotation made it impossible for the patient to reach the opposite axilla or belt buckle. There was a range of acceptability of abduction of forward flexion that did not appear to compromise the eventual functional result. The recommended position is 25 degrees to 40 degrees abduction, 20 degrees to 30 degrees flexion, and 25 degrees to 30 degrees of internal rotation. Even at the ideal position, shoulder fusion produces significant limitations in function. For patients with painful, nonfunctional shoulders who need arthrodesis, these limitations should be clearly discussed, along with the pros and cons of surgical treatment in general.

Anatomy and Biomechanics of the Shoulder in Throwing, Swimming, Gymnastics, and Tennis

As the most mobile joint in the body, the shoulder is structurally insecure. The ball-shaped humeral head rotates and glides on a shallow scapular cup. A limited amount of passive stability is provided by the glenoid labrum, which slightly deepens the scapular cup, and by ligaments reinforcing the capsule on its superior and anterior surfaces. At peak maturity ligamentous restraint equals 50 to 80 kg. These structural limitations indicate that the primary source of joint stability must be balanced muscle control. Joint compression is the major factor. This is supplemented by active tangential restraint, which selectively opposes anterior, posterior, or superior displacement. The large external muscles used for purposeful motion and speed often create subluxating shear forces in addition to the desired actions. Impingement and attrition syndromes are common consequences. To counter this, as well as to provide selective rotation, there are the four muscles that constitute the rotator cuff. Joint compression is the major force generated by the supraspinatus and infraspinatus. The latter (accompanied by the teres minor) also provides a downward pull to oppose the upward displacement of early deltoid action. Anterior protection against excessive external rotation or extension is offered by the subscapularis. Athletic who use the arm for a propelling force strain the extremes of joint range in their drive for maximum performance. The threat of injury can be minimized by two actions, namely, modifying motion patterns, which may avoid impingement or make it a less frequent experience, and active protection, which is gained through specific strengthening of the rotator cuff muscles.

Tibiofemoral Incongruity in Association with Patellar Instability

Ninety-three knees with patellar instability were repaired after conservative treatment failed. In 34 there was evidence of tibiofemoral incongruity consisting of an articular depression of the medial femoral condyle by the meniscus. Secondary articular invasion by synovium occurred in 20 knees. Certain clinical phenomena indicate the presence of this impingement lesion: distinct tenderness over the joint line anterior to the medial collateral ligament, pseudo-locking, and increased pain when walking with the tibia rotated externally. These findings are in addition to the usual parapatellar tenderness, apprehension sign, and crepitus encountered in patellar instability. Excessive external tibial rotation is the probable cause of the impingement rather than genu valgum or dysplasia of the vastus medialis. Hypertension may be a factor. The lesion may play a role in the genesis of osteoarthritis subsequent to patellar instability. Transfer of the tibial tubercle medially may be expected to aggravate tibiofemoral incongruity by increasing tibial external rotation. Other procedures are preferred for patellar stabilization.

Rotation & Torsion of the Leg in Osteoarthritis of the Knee

We studied on the rotation and tibial torsion of the leg in both normal and osteoarthritis of the knees using the horizontal cross rotatory tomography.Method: With the knee full extended, tomographs were taken at following three levels and measured, calculated for t-test of two independent means. (P=0.05)1 femoral condyles 2 tibial condyles just below the articular surface 3 malleoli Results: 1 External rotation of the leg at knee joint increases in osteoarthritis com pared with normal knees.2 The mean angle of the tibial torsion in osteoarthritis is not different statistically significantly from normal knees.3 In operation, it is important not only to correct varus deformity but also excessive external rotation.

Results of the Magnuson operation for recurrent dislocation of the shoulder

T HE problem of recurrent dislocation of the shoulder has troubled orthopedists and surgeons for many years. Numerous theories as to the pathogenesis have been advanced but the following are most commonly accepted. Some authorities, notably Bankhart,’ have described a detachment (usually traumatic) of the glenoid Iabrum from the antero-inferior rim of the glenoid which permits anterior and inferior dislocation of the humeral head. Others (Hill and Sacks) d escribed an abnorma1 groove in the posterolateral quadrant of the humeral head which they believe facilitated recurrent dislocation. Still others, DePalma2 in particular, have found by anatomic studies of a11 ages that the above labral and humeral defects are concomitant with increasing age, but that in the later decades of life, while the bone and labral defects increased in frequency and severity, the incidence of recurrent dislocation declined. From these observations DePalma postulated that other factors must be involved, being convinced that the real causative factor was a tearing and relaxation of the musculotendinous cuff of the shoulder plus a stretching of the other auxiliary stabilizing structures such as the glenohumeral Iigaments and the deltoid muscle. This relaxation permits excessive external rotation of the humeral head which predisposes to dislocation. This postulate is concurred with and appears to account for all the elements necessary to explain this phenomenon. Attempts to correct this disabling condition have been legion. Watson-Jones3 states that sixty different operations have been described. These divide themselves into four classes: tion. This method has not been conspicuously successful. Various suspension operations, such as the Henderson5 and NicolaG procedures, attempting to “snug-up” the humeral head in the glenoid cavity by tendinous slings. These slings passing through bony channels tend to atrophy, become relaxed and finally disintegrate. Bankhart and Putti-Platt believed that by reattaching the glenoid labrum (the typical Bankhartian lesion) or reinforcing the antero-inferior capsule, recurrent dislocations might be prevented. This method has been widely used. In 1945 Magnuson’ proposed an approach to this problem which he believed met all of the factors involved. Recurrent dislocation occurs with the arm in abduction and external rotation. Magnuson believed that by limiting the range of these two types of motion dislocation would be less apt to recur. His method transfers the normal insertion of the subscapularis tendon from the lesser tuberosity to a point distal to the greater tuberosity, thus providing a dynamic musculotendinous sling about the humeral head holding it up, and in internal rotation, preventing dislocation. The author has found this method to be both simple and successful.