Retroversion Angle Research Articles

Changing Glenoid Version After Open Reduction of Shoulders in Children With Obstetric Brachial Plexus Palsy

Twenty-three patients who had obstetric brachial plexus palsy and shoulder subluxation or dislocation that required open reduction and tendon lengthening were entered into a prospective study to evaluate glenoid version after surgery. All the patients had a preoperative computerized axial tomograph and postoperative computed tomography scan of both shoulders at approximately yearly intervals to assess the degree of congruity of the glenohumeral joint and glenoid version. Surgery was performed between 1988 and 1997. There were 11 girls and 12 boys. The mean age was 2 years 5 months (range 8 months-6 years 7 months). The left shoulder was affected in 12 patients and the right shoulder was affected in 11 patients. At mean follow-up of 3 years 7 months, the mean glenoid retroversion for the dislocated shoulder progressively decreased. The difference in glenoid version between the dislocated and the normal side decreased. The angle of glenoid retroversion in the affected shoulders decreased by a mean of 31% after open reduction, and the retroversion continued to improve at 9% per year.

Measurement of the humeral head retroversion angle. A new radiographic method.

In this study, a simple and reliable radiographic method is described to determine the torsional profile of the humeral head. First, by using a specially developed frame, the humeral head retroversion angles (HRAs) of 20 dry humeri were measured by an anatomist and an orthopedist. Then the HRA of these humeri were measured by two orthopedists on radiographs taken in semi-axial view when the humeri were in 20 degrees abduction. The results were assessed with the SPSS 9.05 program, and the repeatability coefficient of both methods was 98%. The average difference in angle determination between the two methods was 0.9 degrees; the maximum difference was 3 degrees. After that, posteroanterior semi-axial radiographs of both humerus bones of 40 healthy volunteers were taken by positioning their arms in 20 degrees abduction to the X-ray axis. The mean HRA difference between the right and left sides was 0.4 degrees (maximum difference 3 degrees ) and is of no clinical significance. It was determined that left and right HRAs can be taken as a reference to each other. For measurement of the HRA in the planning of proximal humeral rotation osteotomy and prosthesis replacement arthroplasty, the presented radiographic method can be used with a high rate of accuracy.

Computed tomography measurement of humeral head retroversion: Influence of patient positioning

For accurate humeral head arthroplasty, the surgeon needs to know some geometric data, such as, for example, the retroversion angle of the humeral head. Only a few reports have described and evaluated the use of computed tomography (CT) to measure humeral head retroversion. The humerus position relative to the roentgen beam is variable from one subject to another depending on the patients' morphology. It could influence the retroversion measurement and has not been investigated previously. This study analyzes in 9 cadaver humeri the variability of retroversion angle measurements with different humerus positioning relative to the roentgen beam during CT examination. The truest retroversion angle can be obtained when true axial slices, perpendicular to the humeral diaphysis, are obtained. Our study tries to clarify technical problems that occur during CT examination. Geometric considerations that can modify the measurements are presented. A reliable method of humeral head retroversion angle measurement is recommended, which could be useful to the shoulder surgeon. (J Shoulder Elbow Surg 2001;10:550-3.)

Computed tomography evaluation of shoulder prosthesis retroversion

Computed tomography (CT) allows calculation of anatomic and prosthetic humeral head retroversion. The purpose of this study was to demonstrate how the retroversion angle measured by CT scan varied with changes in arm position in the CT scan reference system. A trigonometric analysis shows that the measured retroversion angle decreases when the arm is in extension and increases when it is in flexion, compared with the true retroversion angle determined perioperatively. For the same degree of flexion, or extension, the error of measurement is greater when the initial true retroversion is low. A shoulder prosthesis with 20° of true head retroversion was radiologically scanned with different degrees of flexion, extension, and abduction. The results validate the theoretical analysis. Trigonometric formulas are proposed to correct the retroversion angle measured by CT scan. (J Shoulder Elbow Surg 2001;10:546-9.)

In vivo characterization of glenoid with use of computed tomography

Improvement in the treatment of the shoulder could be achieved by accurately describing the pathologic characteristics of the joint. The goal of this study was to characterize, in vivo, glenoids with 3 different diagnoses by using computed tomography (CT): rotator cuff pathology with a limited rupture and without bony changes (group A, n = 15), primary osteoarthritis (group B, n = 13), and rheumatoid arthritis (group C, n = 4). The bone density distribution was assessed by means of the CT value expressed in Hounsfield units. The version angle was also measured. The examination of the CT value showed different distributions according to the pathology. In group A, the cancellous bone presented a central area with a relatively homogeneous and low density. In group B, the reinforcement of the density along with the posterior region seemed to be correlated with the retroversion angle. In the rheumatoid arthritis group, the main characteristic was the loss of the subchondral bone margin. The cartography of the CT value was not reproducible among the 4 cases examined. These in vivo descriptions provide guidelines for the surgeon before total shoulder arthroplasty, helping preoperative planning as well as simulation of implantation. (J Shoulder Elbow Surg 2001;10:116-22.)

The torsional profile of the proximal humeral articular surface

Objectives: To derive the developmental torsional profile of the humerus and to determine a reference value for the retroversion angle of the proximal humeral articular surface (HRA), which can be instrumental in joint replacement arthroplasties performed in our country. Methods: Measurements of the HRA in 14 fetal cadaveric humeri (7 pairs) was accomplished by means of a photographic technique, and in 50 adult cadaveric humeri by means of a specially constructed frame. Measurements of adult HRA were independently made by an orthopedist and an anatomist and repeated after an interval of two weeks. In order to assess the reliability of the anatomic measurement method, calculation of intraclass and interclass correlation coefficients were used for statistical analysis. Results: The mean HRA value was 52.8° in fetal humeri, and 24.9° in adult humeri (maximum 47°, minimum 9°). The interclass correlation coefficient of the anatomic measurement was 98%. Conclusion: It is observed that increased retroversion angle of the proximal humeral joint surface in fetal life decreases in adults. A reference value for HRA can be appropriately used as 25° in joint replacement arthroplasties performed in our country.

Die Behandlung der rezidivierenden Schulterluxation durch Drehosteotomie

According to Weber, from 1989 trough 1995, 32 rotational humeral osteotomies were performed on 31 patients with recurrent shoulder dislocation. Some of the pat. had a functionel Hill-Sachs-lesion. Follow-up was possible on 22 patients with 23 operated shoulders. Mean follow-up was 79 month. Good and excellent results were reached in the Rowescore by 82% and in the Constantscore by 92 % of the patients. There was one recurrence. One patient developed a moderate arthrosis 8 y. after operation. Three of 23 shoulders had a restricted function because of an decreased range of motion and a deficit in strength. 74% of the patients were able to return to their previous occupation and their former levels of sport activities. 90% of the patients rated the result of the operation as good or excellent and would willingly undergo the operation again. Severe complications were 3 nerve paresis. 2 complete radial n. paresis had full recovery and one axillaris n. paresis persisted. There were no osseous complications. For recurrent anterior shoulder dislocation associated with a moderate to severe or respectively functional effective Hill-Sachs lesion, or reduced retroversion angle of the humeral head, the rotational humeral osteotomy is still a successful operation, and most of the patients can achieve an excellent or good result.

Rotational alignment of humerus after closed locked nailing.

Rotational malalignment that may happen during closed nailing of humeral fractures is, to date, an unexplored area of investigation. The purpose of this study was to examine the effect of arm position during surgery on humeral rotational alignment and the effect of this alignment on shoulder motion and function. Thirty patients with eventual fracture healing after closed humeral locked nailing were retrospectively studied: 15 had retrograde nailing; 15, antegrade. Retrograde nailing was performed with the patient in a decubitus position and with the upper arm anteriorly flexed and the forearm perpendicular to the operating table. Antegrade nailing was performed with the patient in a semisitting position and with the upper arm in the so-called resting position. The humeral retroversion angle as measured by computed tomographic scan, range of shoulder rotation, and Neer score of the shoulder for the fractured and the intact humeri were determined, and the discrepancy (i.e., value for the intact subtracted from that for the fractured) between the two was noted. To test the effect on alignment of positioning during retrograde nailing, we similarly determined retroversion angles for another 15 patients treated in a supine resting position. Between antegrade nailing and retrograde nailing in decubitus position, there was a significant difference in the mean discrepancies for the retroversion angles and the range of external rotation of the shoulder in the neutral and abduction positions, but no significant difference for internal rotation of the shoulder and Neer score. Between antegrade nailing and retrograde nailing in supine resting position, there was no significant difference in the mean discrepancy for the retroversion angle. Positioning of the arm may significantly affect humeral rotational alignment and range of motion during closed nailing. Until a reliable method for intraoperative measurement of humeral rotation is devised, we recommend that closed nailing of humeral shaft fractures be performed with the patient's upper arm in the resting position shown in this study.

Variations in the retroversion of the humeral head

It is generally accepted that the humeral head in adults is retroverted between 25° and 35°. To assess the validity of this belief, 336 dry bone specimens of humeral heads were measured. The specimens were taken from various ethnic groups: white Americans, black Americans, New Mexican Indians, northern Chinese, Alaskan Eskimos, and Negev Desert bedouins. There was significant variation in retroversion angle between specimens from different ethnic groups and even wider variation between specimens within particular groups—a finding contrary to popular belief. Retroversion angle in the specimens ranged from −8° to +74°. In addition, 50 fetal skeletons of white and black Americans were studied. The mean humeral head retroversion angle in the fetal skeletons was 78°, much greater than that in adults. It was evident that the large retroversion angle in the very young decreases with growth and that it does so to a varying extent among different ethnic groups and individuals. It is of clinical importance to understand the variations in humeral head retroversion among individuals undergoing operation and the ways in which this parameter might be manipulated to surgical advantage.

Study on Long Bones: Variation in angular traits with sex, age, and laterality

The biological problems considered in this study are sexual dimorphism in angular osteometric traits, changes in these traits with aging and their bilateral asymmetry in the same individual. The sample comprises the right and left long bones of 200 skeletons (100 males and 100 females) of Sardinian adults (Frasetto collection) for whom the sex and age at death are known. As concerns the sexual dimorphism, some angular traits of upper limb (joint axis angle of the ulna in particular) and the lower limb (condylo-diaphyseal angle of the femur and retroversion angle of the tibia) are significantly different between males and females. Torsion angles of long bones (especially the femur) were found to change with age. In sides comparison revealed a clear right-left asymmetry in our sample. The asymmetry, sexual dimorphism and changes with age are discussed in relation to varying stresses of different living activities. Our data indicate that the angular traits of long bones could be very informative in biomechanical interpretations of human activities based on skeletal remains.

Comparison of humeral head retroversion with the humeral axis/biceps groove relationship: A study in live subjects and cadavers

The purpose of this study was to investigate whether the axis of the humeral articular surface bears a more constant relationship to the bicipital groove than to the distal humerus. This finding could help intraoperative placement of a shoulder prosthesis in the most anatomic position. Magnetic resonance imaging was used in 41 live volunteers and 9 cadavers to measure the distance from the biceps groove to a line drawn perpendicular to the midpoint of the humeral articular surface. A cadaver model with a plastic humeral prosthesis was used to convert this biceps distance into an angular measurement. The relationship between the biceps distance and the retroversion angle of the humeral head with respect to the humeral epicondyles was analyzed. The biceps distance averaged 11.8 mm ± 3.5 mm (equivalent to 26.8° ± 8.3°), whereas retroversion averaged 26.8° ± 12.2°. This difference in variability is significant (P = .008). Placing the fin of a humeral head implant 12 mm posterior to the biceps groove reproduces normal anatomy better than the use of an arbitrary standard of 30° to 40° of retroversion.

Normal Humeral Head Retroversion Angle in Korean Measured with Semil - axial View

Normal Humeral Head Retroversion Angle in Korean Measured with Semil - axial View

Influence of glenohumeral prosthesis geometry and placement on shoulder muscle forces.

The authors studied the influence of a changed geometry of the glenohumeral joint on the function of the muscles with the use of a shoulder prosthesis with an anatomic design. The changed geometry is characterized by 4 parameters: orientation of the glenoid, radius of the humeral head, position of the glenohumeral joint's geometric center in relation to the scapula, and position of the glenohumeral joint's geometric center in relation to the humeral shaft. The effect of changes in these 4 parameters was investigated with an inverse dynamic 3-dimensional musculoskeletal model of the shoulder. This was done at 60 degrees and 90 degrees of abduction and flexion. Gravity was the only external force on the arm. The magnitudes of the introduced changes are assumed to be a realistic representation of a changed geometry due to the implantation of a prosthesis. In most situations, the effect of a change in the 4 parameters on the exerted muscle force was small compared with the maximum force of a muscle. However, in relation to the initial reference force in a muscle, changes with an average of 50% occurred. Changes in the geometric center's position relative to the humerus are especially important, because they are closely related to the retroversion angle and can cause changes in force of up to 300%.

Rotation osteotomy of the proximal humerus to stabilise the shoulder. Five years' experience

A reduced retroversion angle of the humeral head may predispose to recurrent anterior shoulder dislocation and may also be a factor in persistent instability after soft-tissue repair. We performed rotational osteotomy of the proximal humerus in 20 patients with recurrent anterior shoulder dislocations (10 traumatic, 10 non-traumatic) and a decreased retroversion angle of the humeral head. The mean preoperative retroversion angle was 12 degrees, which was increased after surgery to a mean value of 32 degrees. All patients regained a normal range of shoulder motion and normal function within three months after surgery. At the five-year review all shoulders were stable, pain-free and had no radiological signs of osteoarthritis.

Retroversion of the proximal humerus in relationship to prosthetic replacement arthroplasty

Arthroplasty of the proximal humerus positions a prosthetic articular surface in relation to the humeral canal. Most descriptions of surgical technique recommend positioning the humeral component in 30 degrees to 45 degrees of retroversion. This study measured retroversion in relationship to the surgically reamed canal and introduced a method of measurement pertinent to prosthetic reconstruction. The canals of 21 cadaveric humeri were surgically reamed, the articular margins of the humeral heads were outlined with steel wire, and the trochlear axes were transfixed with Steinman pins. Under fluoroscopy the humeri were rotated on a jig that allowed rotation around the reamer and measurement of retroversion relative to the plane of the articular surface. Retroversion of the proximal humerus is highly variable, ranging in this study from 10 degrees to 55 degrees (mean 29.8 degrees). Anatomic reconstruction of the retroversion angle must be individualized. Palpation of the rotator cuff insertion is recommended prior to humeral head resection to avoid inadvertant cuff injury.

Assessment of Rotation in Proximal Humeral Osteotomy

The correlation between the shift measured on bone surface in rotatory osteotomy and the radiologic change of the retroversion angle was analyzed. The humeral head retroversion was measured radiographically in 7 isolated humeri by means of a semiaxial projection. All bones were then osteotomized and the humeral head rotated in order to increase and decrease the retroversion. The retroversion was measured radiographically for each new rotational position of the head. The relationship between the measured shift in rotatory osteotomy and the change of retroversion was found to be linear. Twelve patients with recurrent anterior shoulder joint dislocations and a small humeral head retroversion were operated on in order to increase the retroversion. In all patients the increase of retroversion angle was smaller (57%) than expected on the basis of the shift in osteotomy and humeral diameter. The mean increase of retroversion was 2 degrees/mm shift (range 1.3-3.0 degrees/mm).

STABILITY IN RELATION TO HUMERAL HEAD RETROVERSION AFTER SURGICAL TREATMENT OF RECURRENT ANTERIOR SHOULDER DISLOCATIONS

This study reports the influence of the retroversion angle on the postoperative stability in 50 patients operated on for recurrent shoulder dislocations. Fifty-two shoulders were reviewed by radiographic and clinical examinations. Particular attention was focused on humeral head retroversion, shoulder stability, and range of motion in relation to surgical technique. The retroversion angle was significantly reduced in 30 of 47 shoulders, for which satisfactory radiographs could be achieved. Mean humeral head retroversion was 24 degrees for both dominant and nondominant shoulders. Forty-eight of 52 reexamined shoulders became stable. Four had remaining instability following a Putti-Platt procedure, with a mean retroversion angle of 18 degrees. A reduced humeral head retroversion is therefore proposed as an important factor in creating instability, and may be one explanation for failed stability after soft tissue repair. Irrespective of the type of surgical procedure (Bristow or Putti-Platt), there was a significant decrease in range of shoulder rotation in the operated shoulder compared to the contralateral stable shoulder and to reference values for normal controls. However, decreased rotation was not found to impair shoulder function, and 48 of the 50 reexamined patients generally improved after surgery.

Surgical and methodologic aspects of proximal humeral osteotomy for stabilization of the shoulder joint

It has previously been shown that a small retroversion angle might predispose to recurrent anterior shoulder dislocation, and in patients with remaining instability after soft-tissue repair the retroversion angle is often reduced. In these patients a rotation osteotomy of the proximal humerus to correct the anatomy in order to stabilize the joint can be advocated. The surgical technique for subcapital rotational osteotomy of the humerus is presented in this report. An isolated humerus has been osteotomized and radiographically examined in various positions. These findings, supplemented with mathematic calculations of the relationship between shift in millimeters of the osteotomy and angle of correction, have provided guidelines for obtaining accurate correction of the humeral head retroversion angle at surgery. The method has been used in seven patients with recurrent anterior shoulder dislocations, and all patients were operated on with a rotational osteotomy. Mean retroversion before surgery was 15°. It was changed after surgery to a mean value of 32°. All shoulders became stable and pain-free and had a normal range of motion. At the 3-year follow-up no radiologic signs of osteoarthrosis were found.

Proximal Humeral Osteotomy to Correct the Anatomy in Patients with Recurrent Shoulder Dislocations

Surgical treatment of patients with traumatic shoulder dislocations is usually successful, but soft-tissue surgery in patients with nontraumatic shoulder dislocation often fails to stabilize the joint. Previous studies have shown that decreased humeral head retroversion might be one cause of anterior shoulder instability. Eleven patients with anterior recurrent dislocations, five traumatic and six nontraumatic, and all with a small humeral head retroversion angle, have been operated on using a proximal humerus osteotomy to correct the abnormal anatomy. After surgery, the humeral head retroversion was normalized to a mean angle of 34 degrees. All shoulders became stable. External rotation increased 7 degrees on the average, and internal rotation decreased 10 degrees on the average. One year after surgery, shoulder function was excellent in all operated shoulders.

Humeral Head Retroversion in Patients With Unstable Humeroscapular Joints

Humeral head retroversion and shoulder rotation in both the frontal and scapular plane were studied in 34 patients with anterior glenohumeral instability. Twenty-two patients had traumatic anterior shoulder dislocations and another 12 patients had nontraumatic dislocations with generalized joint laxity. Patients with traumatic recurrent dislocations had a smaller than normal retroversion angle in the unstable shoulder. The angles were 26 degrees on the dominant side and 23 degrees on the nondominant side compared with 33 degrees and 29 degrees, respectively, in normal shoulders. The stable contralateral shoulder joint was clinically and roentgenographically similar to the normal shoulder. The patients with nontraumatic dislocations had increased rotation and smaller retroversion angles, irrespective of stability in the shoulder joint. The retroversion angles were 18 degrees for unstable shoulders on the dominant side and 15 degrees on the nondominant side. The retroversion angle of the stable contralateral joint in these patients was less in five of eight shoulders.