Normal Glenohumeral Relationship Research Articles

A Study of Normal Glenohumeral Relationships in Patients Attending A Tertiary Care Health Centre

A Study of Normal Glenohumeral Relationships in Patients Attending A Tertiary Care Health Centre

Functional evaluation of management modalities of three and four part proximal humeral fractures

Introduction: Three and four –part fractures represent 13%-16% of proximal humeral fractures. They occur more frequently in older patients after the cancellous bone has become weakened by senility and osteopenia. Treatment options for these displaced fractures include closed reduction and k-wire fixation, open reduction and internal fixation and arthroplasty. The purpose of the present study was to evaluate the functional results in patient with three and four-part proximal humeral fractures treated by different modalities, over a period of 2 years. Materials and Methods: We present a retrospective study of 40 three-part and four part proximal humeral fractures according to Neer’s classification, treated by simple technique of Kirschner wire Osteosynthesis, open reduction and internal fixation with clover-leaf plate or proximal humeral locking plate system (PHILOS) and hemiarthroplasty of the proximal humerus. The criteria for inclusion were a diagnosis of undisplaced three-part fracture, displaced three and four part fractures confirmed by three independent observers. Results: The study was conducted over a period of two years with an average follow up of 20.7 months (Range: 12 to 40 months). There were 14 undisplaced three-part fractures impacted in valgus, seven displaced three part fractures, two three-part fracture with dislocated head, four four-part fractures with dislocated head. Conclusion: Three-and four-part proximal humeral fractures are difficult injuries to evaluate and treat. Nevertheless, an algorithm for treatment has been devised. Preoperative and intraoperative evaluation must address fracture pattern, bone quality, patient motivation, and expectations. A thorough knowledge of normal glenohumeral relationships is essential to achieve optimal surgical results.

Analyzing on the location of the bicipital groove for alignment in shoulder arthroplasty of Chinese.

Many anthropometric studies of the normal glenohumeral relationship have been performed for the implant design and to identify reference points for the correct placement of the prosthesis in glenohumeral joint replacement. However, whether those implantation marks, which adopted from European or American, can achieve the same precision to Eastern Asian, specifically Chinese is still unknown. One hundred eighty healthy were scanned using CT. Their humeri were measured to determine humeral head retroversion and its relation to the location of the bicipital groove. The angle between the transepicondylar axis and the line connected the centre of the head sphere and the lateral lip point of the bicipital groove, and the plane through the humerus shaft axis and the lateral lip of the bicipital groove in the horizontal plane were measured and denoted by angle-α and angle-β, respectively. The biceps distance (BD) from the lateral lip of the bicipital groove proximally to the axis of humeral head in the horizontal plane was also measured. The average angle α and β was 40.08° (±11.15°) and 42.19° (±12.64°). The average BD was 7.15mm (range 0.87-13.94mm; SD 2.55mm). The linear relationship between humeral head retroversion and the bicipital groove angle α can expressed as α=0.7125×retroversion+24.8128 (R2=0.5956). If the centre of the lateral aspect of the stem has a posteriorly offset of 20° from the lateral lip of the bicipital groove, the component would have a proximal 20° of retroversion. The results indicate that the bicipital groove can be used as a landmark for prosthetic stem positioning in shoulder arthroplasty. Moreover, it is different from the current standard technique of cutting the proximal humerus at 30° of retroversion with the epicondyles or forearm used as a guide.

The glenohumeral joint - a mismatching system? A morphological analysis of the cartilaginous and osseous curvature of the humeral head and the glenoid cavity.

BackgroundRadial mismatch, glenohumeral conformity ratios and differences between cartilaginous and osseous radii highly depend on the measured plane. The comparison of cartilaginous radii between humeral head and glenoid in different planes provides new information to understand the degree of conformity during abduction of the upper limb.MethodsTo investigate the radii, CT-images in soft-tissue kernel of 9 specimen were analysed using an image visualization software. Statistical analysis of the obtained data was performed using the t-test.ResultsMeasurements of the radii in the glenoid revealed a significantly larger radius for bone than cartilage, whereas for the humeral head the opposite was the case. Highest ratios for cartilage in the transverse plane were found in the inferior and central areas of the joint surface, whereas the smallest ratios were found in the superior area. The radial mismatch varied between 0.1 mm and 13.6 mm, depending on the measured plane.ConclusionsThe results suggest that in abduction, the cartilaginous guidance of the humeral head decreases. This might permit the humeral head an anterior-posterior shifting as well as superior-inferior translation. Surgical reconstruction of the normal glenohumeral relationships necessitates precise information about the glenohumeral morphology to ensure proper sizing and correct placement of prosthetic components and osteochondral allografts.

Resurfacing humeral prosthesis: do we really reconstruct the anatomy?

The goal of a resurfacing shoulder arthroplasty is to reproduce the individual's anatomy while preserving the bone stock of the humeral head. This study investigated the hypothesis that resurfacing the humeral prosthesis restores normal glenohumeral relationships and correlates with the final clinical results. A resurfacing shoulder implant was performed in 61 patients (64 shoulders). Indications were primary osteoarthritis in 26, secondary osteoarthritis in 21, avascular necrosis in 4, rheumatoid arthritis in 4, dysplasia in 4, and for others indications in5. At an average of 36 months (range, 24-65) of follow-up , the Constant score reached 68 points and the Quick-Disabilities of Arm, Shoulder and Hand score reached 28 points. Preoperative and postoperative radiographic analysis showed a decrease of the humeral head diameter (51 ± 5 vs 48 ± 5 mm) and of the height of the humeral head (21 ± 4 vs 19 ± 2 mm), without modification of the radius of curvature or the height of the center of rotation. The medial humeral offset increased from 3.3 ± 3.5 to 6.4 ± 3 mm and the lateral offset from 6.8 ± 9 to 10.4 ± 9 mm. The implant was mainly in varus postoperatively compared with preoperative values (122° ± 11° vs 134° ± 7°). Postoperative radiographic analysis and at the last follow-up did not show any significant difference, except for the increase of the depth of the glenoid from 4.2 ± 1.4 to 4.9 ± 1.8 mm. The resurfacing shoulder arthroplasty reproduces the normal anatomy and compensates glenohumeral wear. However, there was a tendency to position the prosthesis in varus because of technical imperfections. With follow-up, medialization of the humerus with glenoid wear was observed and was correlated in some patients with reappearance of pain.

Subscapularis Release in Shoulder Replacement Determines Structural Muscular Changes

Osteotomy of the lesser tuberosity in shoulder arthroplasty allows bony healing of the subscapularis tendon but does not prevent fatty degeneration in its muscle. Occurrence or increase in fatty degeneration may depend on the surgical technique. We (1) assessed fatty degeneration in the subscapularis muscle and its cross-sectional area after a C-block osteotomy of the lesser tuberosity with minimal mobilization of the subscapularis muscle, and (2) determined whether this technique had any adverse effect on function, fatty degeneration, and cross-sectional area of the subscapularis muscle. We retrospectively examined 36 patients with shoulder replacements who had C-block osteotomies. Constant-Murley scores and clinical signs of subscapularis insufficiency were recorded. We radiographically assessed prosthetic placement. On CT scans, lesser tuberosity healing, fatty degeneration, and cross-sectional area of the subscapularis muscle were determined. The minimum followup was 13 months (mean, 18 months; range, 13-33 months). The mean absolute Constant-Murley score was 71.2. Two patients had weakness of the subscapularis muscle without loss of active motion. All tuberosities healed anatomically. A normal glenohumeral relationship was found in all cases. Fatty degeneration was Grade 0 in 44%, Grade 1 in 39%, Grade 2 in 14%, and Grade 3 in 3%. The subscapularis muscular cross-sectional area decreased from 16.7 cm(2) preoperatively to 14.5 cm(2) postoperatively (13%). The C-block osteotomy with minimal dissection of the subscapularis is associated with a low incidence of fatty degeneration in the subscapularis muscle after shoulder arthroplasty although the muscular cross-sectional area of the subscapularis decreased. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

A 3D-CT scan study of the humeral and glenoid planes in 150 normal shoulders

The purpose of the study was to determine the normal three-dimensional relationship between the humeral and the glenoid plane of the individual patient. We measured the three-dimensional angle between the glenoid plane and the humeral plane (glenohumeral angle, °GH) and the angle between the plane of the scapula and the plane of the glenoid (glenoscapular angle, °GS) with the patient in a standardized position to the CT scan gantry. We hypothesized that a normal distribution with a small variation would exist for both angles. A total of 150 conventional CT scans of normal shoulders from patients aged between 18 and 80 years were examined and three-dimensional reconstructions were derived from it. The descriptive statistics and the variability of °GH and °GS were determined. The mean °GH was 57.9°, and the mean °GS was -3.77°. The overall reliability of the measurement was good. Descriptive statistics of this study confirm the normal distribution and a narrow variation of both parameters. This is the first study to determine the normal 3D relationship between the humerus and the glenoid (°GH). This new three-dimensional anatomical information of the normal glenohumeral relationship and glenoid can be used to distinguish normal from pathological anatomy, as well as alternative surgical guidance especially in bony deficient glenoids. Level of Evidence Level II Anatomical Study.

Glenohumeral relationship in the transverse plane of the body

Reconstruction of a normal glenohumeral relationship is desirable for a successful arthroplasty. Double-contrast computed tomography was performed on 49 healthy shoulders in young volunteers. For creation of a uniform spatial reference system, the subjects were positioned in a thoracobrachial orthosis with the arm adducted in the coronal plane and the forearm flexed in the sagittal plane, and they were examined in dorsal recumbency. The classical anatomic angles were measured, and the anatomic axes were determined and quantified as angles to the coronal plane. When the axis of the glenoid was correlated to the axis of the humeral head, a mean of 8.5° divergence in a clear Gaussian distribution was found. This contrasts with the variability of the version of the humeral head and of the glenoid and offers a useful guideline in difficult prosthetic surgery of the shoulder in which normal anatomic landmarks are lost because of arthritic or traumatic deformity.

Analysis of the bicipital groove as a landmark for humeral head replacement

Many anthropometric studies of the normal glenohumeral relationship have been performed in an effort to identify reference points for the correct placement of the humeral head prosthesis in shoulder arthroplasty. The bicipital groove offers a useful landmark for placement of the lateral fin of the prosthesis. However, when fracture surgery is performed, only the distal portion of the bicipital groove may be available for reference. We evaluated the course of the bicipital groove as it moves distally along the humerus. Computer-assisted tomography axial images of 21 cadaveric humeri were obtained in order to follow the course of the bicipital groove from proximal to distal on the humerus. With use of the bisector of the transepicondylar axis as a reference point, the relative change in position of the bicipital groove from proximal to distal was measured. The mean change in rotation of the lateral lip from the proximal to the distal groove was 15.9°, with an SD of 6.8° (range, 4°-32°). The 95% confidence interval range for the change was 12.8° to 19°. Thus, a significant amount of internal rotation occurs along the course of the bicipital groove. This has significant clinical implications when the bicipital groove is used as a landmark for humeral head replacement in fractures of the proximal humerus. (J Shoulder Elbow Surg 2002;11:322-6)

A new in vivo technique for three-dimensional shoulder kinematics analysis.

The field of shoulder kinematics research has long relied upon the use of cadaveric models or invasive techniques in human volunteers. In this paper, a novel method is presented that utilizes magnetic resonance imaging (MRI) and a software system called 3DVEWNIX. This method permits non-invasive, repetitive evaluation of living patients for glenohumeral kinematics analysis. The objectives of this study were twofold: to validate the quantitative accuracy of this technique; and to demonstrate glenohumeral relationships in asymptomatic volunteers during internal and external rotation of the arm. The translational accuracy was first assessed by comparing known cadaveric glenohumeral translations with calculations from MR images of the cadaver. Nine asymptomatic volunteers were subsequently placed in an external shoulder positioning device in the scanner and imaged in 10 degrees increments of actively achieved internal and external rotation. Three-dimensional reconstructions of the glenoid and humerus were used to evaluate the glenohumeral relationships in the tested positions of rotation. The quantitative analysis revealed an error of 0.61 mm (SEM 0.11 mm). Examination of the volunteers demonstrated normal relationships about the glenohumeral joint in internal and external rotation. In addition, this method provided detailed images of the bony surface architecture from any perspective. These images can be transformed into a cinematic three-dimensional depiction of active shoulder rotation. This new technique offers an accurate, non-invasive method for assessing the normal glenohumeral relationships in shoulder kinematics. We now possess the capability to investigate the kinematics of normal and abnormal shoulder conditions non-invasively in a large patient population.

Anthropometric study of normal glenohumeral relationships

Ninety-three cadaveric proximal humeri and matching scapulae with no evidence of shoulder disease were obtained. High-resolution roentgenograms were made. They were then digitized, and a custom computer program was used to obtain periosteal and endosteal dimensions (humeral canal width, shaft width, tuberosity offset, head offset, radius of curvature, head diameter, canal flare index, glenoid height and depth, arc of enclosure, radius of curvature, and depth of cancellous bone, among others). Statistical analyses included correlations among pairs of dimensions, regression analysis, and confidence intervals to estimate each geometric parameter. To represent the degree of conformity and constraint between the humeral head and glenoid, a conformity index (radius of head/radius glenoid) and constraint index (arc of enclosure/360) were calculated for each shoulder. Most of the parameters measured approximated a Gaussian distribution. Pairwise correlations of the geometric parameters showed that many were significantly associated at the 5% level (p < 0.05) with a high correlation coefficient (r > 0.4), meaning that the variations between the parameters were not purely random but rather they were related and that this relationship was useful in a predictive sense. With these key parameters identified, one can design components with an optimum fit or match an existing design to a patient's anatomy with a high degree of accuracy. No correlation was found between the radii of curvature for the humeral head and glenoid in either the coronal or sagittal plane or between the humeral head diameter and arc of enclosure. The mean conformity index was 0.72 in the coronal and 0.63 in the sagittal plane. Only 16% of the specimens had a conformity index greater than 0.9, indicating the radii of curvature matched. The vast majority had a more curved humeral head and flatter glenoid. Also, there was more constraint to the glenoid in the coronal versus sagittal plane (constraint index = 0.18 vs 0.13). These anatomic features help prevent superior-inferior translation of the humeral head but allow translation in the sagittal plane. This database of basic anatomic geometry defines the anatomic relationships of the proximal humerus and glenoid cavity that allow for a precise bone-implant fit and assesses the match between the shape of existing components and the patient's anatomy.

The normal glenohumeral relationships. An anatomical study of one hundred and forty shoulders.

We measured the dimensions of the humeral and glenoid articular surfaces in 140 shoulders that were representative of a given population of patients, and also evaluated several glenohumeral relationships. Ninety-six measurements were made in the shoulders of cadavera and forty-four, on magnetic resonance-imaging studies of living patients. Eighty-five per cent of the humeral measurements fell within eight fixed combinations of the radius of curvature and the thickness of the humeral head, in two-millimeter increments. The average radius of curvature of the humeral head in the coronal plane was 24 +/- 2.1 millimeters (range, nineteen to twenty-eight millimeters). The average thickness of the humeral head was 19 +/- 2.4 millimeters (range, fifteen to twenty-four millimeters). There was a wide variability in the size of the humeral head and a direct correlation between the differences in size and the heights in both men and women. The humeral articular surface was spherical in the center; however, the peripheral radius was two millimeters less in the axial plane than in the coronal plane. Thus, the peripheral contour of the articular surface was elliptical (ratio, 0.92). The radius of curvature of the glenoid, measured in the coronal plane, was an average of 2.3 +/- 0.2 millimeters greater than that of the humeral head. The average dimensions of the glenoid in the superior-inferior and anterior-posterior (lower half) directions were 39 +/- 3.5 millimeters (range, thirty to forty-eight millimeters) and 29 +/- 3.2 millimeters (range, twenty-one to thirty-five millimeters). The anterior-posterior dimension of the glenoid was pear-shaped, the lower half being larger than the top half. The ratio of the lower half to the top half was 1:0.80 +/- 0.01. There was a strong linear correlation between the lateral humeral offset and the size of the humeral head (radius of curvature and thickness). The average lateral humeral offset was 56 +/- 5.7 millimeters (range, forty-three to sixty-seven millimeters). The superior most point on the humeral articular surface was an average of 8 +/- 3.2 millimeters (range, three to twenty millimeters) cephalad to the top of the greater tuberosity. Our data show that reconstruction of the lateral humeral offset is important in optimization of the moment arm of the deltoid and rotator cuff and of the normal tension of the soft tissue after prosthetic reconstruction.

Postoperative proximal migration in total shoulder arthroplasty: Incidence and significance

A retrospective review of 131 Neer total shoulder arthroplasties in 111 patients performed between 1974 and 1986 was undertaken to identify factors associated with proximal humeral migration. The influence of proximal migration on results was evaluated to clarify the indications for prosthetic constraint. The average follow-up period was 55 months (range: 24–124 mo). The results showed proximal migration in 22% of patients (29 shoulders). The migration was progressive in all cases, without corresponding increases in pain. Major rotator cuff tears were present in 21% of patients with a normal glenohumeral relationship and in 24% of the patients with proximal migration. Limited elevation was noted in patients with proximal migration, but all patients had improved range of motion and decreased postoperative pain. The cause of postoperative proximal migration is believed to be secondary to a combination of factors and not rotator cuff disruption alone. These data do not support the routine use of a constrained prosthesis for irreparable rotator cuff tears