Age-dependent variation of glenohumeral anatomy: a radiological study

Minimum two-year follow-up of a reverse total shoulder arthroplasty using a wedged baseplate

Background

Avoiding inclination of the glenoid baseplate in reverse shoulder arthroplasty often requires considerable glenoid reaming. It is proposed that the use of a metal wedged baseplate in all patients can achieve neutral inclination with reduced glenoid reaming.

Materials and Methods

A prospective clinical single-centre study with minimum two-year follow-up was carried out. Glenoid deformity was classified on CT and surgery planned using BluePrintTM. The Tornier Perform® Reversed Wedged Augmented Glenoid was used in all cases. Clinical outcome scores and radiographs were assessed.

Results

Seventy-three patients, mean age 76.6 years. Twenty-eight demonstrated no glenoid deformity and 19 demonstrated marked retroversion. Seventy completed two-year follow-up. Mean pain scores fell from 6 to 0.7. All Patient Reported Outcome Meaures (PROMS) were significantly improved. Active elevation increased by 62° and external rotation by 28.7° (p < 0.001). In patients with no glenoid wear (E0/A1), correction of inferior inclination was achievable with a 15° full-wedge baseplate in all cases, reducing the reaming depth by 4.4 mm (p < 0.001). In patients with severe glenoid wear, a 35° half wedge baseplate was often necessary to correct the deformity. The most common complications were stress reactions/fractures.

Conclusion

A metal wedged baseplate can achieve neutral inclination in all patients, minimising bone reaming and preserving lateralisation with good two-year outcomes.

Level of evidence

IV (case series with no comparison group).

Assessment of the Glenoid Morphology Based on Demographic Data in the Turkish Population

Purpose

In this study, our aim was to evaluate the glenoid version, height, and width measurements based on gender, side, age, height, and hand dominance in the Turkish population using computed tomography (CT) images.

Methods

In our study, CT images of 140 patients (62 females and 78 males; mean age: 39.6 years) who had no shoulder complaints were evaluated retrospectively. Glenoid version (GV), AP diameter (width), and SI diameter (height) on both shoulders were measured on the CT images. Correlations between patient gender, side, age, height, and hand dominance and the GV and size were evaluated.

Results

The right shoulder had a mean GV of −0.93 ± 7.80 degrees and the left shoulder had a GV of −0.88 ± 6.63 degrees (p > 0.05). The mean AP diameter of the glenoid was 26.57 ± 3.02 mm in the right shoulder and 26.33 ± 3.01 mm in the left shoulder (p > 0.05). The mean AP diameter of the glenoid was 26.57 ± 3.02 mm in the right shoulder and 26.33 ± 3.01 mm in the left shoulder (p > 0.05). The mean AP diameter of the glenoid was 26.57 ± 3.02 mm in the right shoulder and 26.33 ± 3.01 mm in the left shoulder (p > 0.05). The mean AP diameter of the glenoid was 26.57 ± 3.02 mm in the right shoulder and 26.33 ± 3.01 mm in the left shoulder (p > 0.05). The mean AP diameter of the glenoid was 26.57 ± 3.02 mm in the right shoulder and 26.33 ± 3.01 mm in the left shoulder (p > 0.05). The mean AP diameter of the glenoid was 26.57 ± 3.02 mm in the right shoulder and 26.33 ± 3.01 mm in the left shoulder (p > 0.05). The mean AP diameter of the glenoid was 26.57 ± 3.02 mm in the right shoulder and 26.33 ± 3.01 mm in the left shoulder (p > 0.05). The mean AP diameter of the glenoid was 26.57 ± 3.02 mm in the right shoulder and 26.33 ± 3.01 mm in the left shoulder (

Conclusion

Hand dominance had an effect on the glenoid version, while patient gender, age, and height had an effect on the glenoid size. The glenoid width in the Turkish population was similar to that of the European and American populations, and the glenoid height was similar to that of the Asian population. Our GV values were similar to those of the Asian population and more anteverted compared to the Western population. We believe that our findings will be useful in preoperative planning and in the production of implants for our population.

Middle-aged adults cocontract with arm ADductors during arm ABduction, while young adults do not. Adaptations to preserve pain-free function?

Middle-aged individuals cocontract with adductor muscles during abduction. This may be crucial for counteracting deltoid forces, depressing the humerus and ensuring free passage of subacromial tissues underneath the acromion during abduction. We questioned whether adductor co-contraction is always present, or develops during ageing, in which case it may explain the age-related character of common shoulder conditions such as Subacromial Pain Syndrome. In a cross-sectional analysis with electromyography (EMG), activation patterns of the latissimus dorsi, teres major, pectoralis major and deltoid muscle were assessed during isometric force tasks in 60 asymptomatic individuals between 21 and 60 years old. Cocontraction was expressed as the degree of antagonistic activation relative to the same muscle's degree of agonistic activation, resulting in an activation ratio between -1 and 1, where lower values indicate more cocontraction. Using linear regression analyses, we found age-related decreases in the activation ratio of the latissimus dorsi (regression estimate: -0.004, 95% CI: -0.007 to 0.0, p-value: 0.042) and teres major (regression estimate: -0.013, 95% CI: -0.019 to -0.008, p-value: <0.001). In contrast to young individuals, middle-aged individuals showed a high degree of adductor cocontraction during abduction. This may indicate that during ageing, alterations in activation patterns are required for preserving pain-free shoulder function.

Reliability of measurements performed on two dimensional and three dimensional computed tomography in glenoid assessment for instability

PURPOSE

The main purpose of this study is to establish which of two methods is more reliable in glenoid assessment for instability in pre-operative planning. Accordingly, we have studied the intra- and inter-observer reliability of glenoid parameters with the use of two-dimensional (2D) and three-dimensional (3D) reconstructed computed tomography (CT) images.

METHODS

One hundred glenoids were measured with the use of 2D-CT and 3D-CT (in 3D orientation) by two independent observers (one experienced and one inexperienced). Measurements were repeated after one week for 30 randomly selected glenoids.

RESULTS

The intra-class correlation coefficient (ICC) for inter-observer reliability was significantly greater for 3D-CT (0.811 to 0.915) than for 2D-CT (0.523 to 0.925). All intra-observer reliability values for 3D-CT were near perfect (0.835 to 0.997), while those for 2D-CT were less reliable (0.704 to 0.960). A dependent t-test showed that, for both observers, almost all glenoid parameters (except R and d) differed significantly (p < 0.05) between 2D and 3D measurement methods.

CONCLUSIONS

Therefore, it can be concluded that 3D glenoid reconstructions are more reliable for glenoid bone loss assessment than 2D-CT. The results suggest that quantifying a glenoid defect with the use of 2D image only-even if performed by an experienced orthopaedic surgeon-is prone to errors. Differences in measurements between and within observers can be explained by plane setting and identifying glenoid rim in 2D-CT. Accordingly, we recommend that glenoid measurements should be performed in 3D orientation using 3D reconstruction obtained from CT images for pre-operative assessments, which are crucial for surgical planning.

The osseous morphology of nondegenerated shoulders shows no side-related differences in elderly patients: an analysis of 102 computed tomography scans

BACKGROUND

A precise understanding of glenohumeral anatomy is required to optimize preoperative planning in shoulder joint arthroplasty, which is difficult in the presence of degenerative disease. In unilateral disease, the contralateral shoulder can be used as a representation of normal anatomy; however, intrasubject differences in shoulder morphology have not been investigated.

METHODS

A retrospective study of all patients aged >65 years who received whole body computed tomography at our trauma center from 2010 through 2014 was conducted. Right and left shoulder computed tomography scans were examined, and the following anatomic parameters were measured: humeral head diameter in anteroposterior and axial views, glenoid diameter in anteroposterior and axial views, glenoid surface, scapula neck depth, neck-shaft angle, glenoid inclination, glenoid/head ratio, and glenoid version. Patients with inadequate scan quality, osseous lesions, pre-existing anatomic abnormality, or metallic implant at the shoulder region and significant osteoarthritis were excluded.

RESULTS

The study analyzed 102 shoulders of 51 patients. Mean age was 71.4 ± 8.2 years. Humeral head and glenoid diameters, scapula neck depth (right, 36 ± 8 mm; left, 36 ± 7 mm; P = .684), glenoid/head ratio (right, 0.6 ± 0.1; left, 0.6 ± 0.0; P = .961), and glenoid surface (right, 790 ± 152 mm(2); left, 754 ± 134 mm(2); P = .215) showed no significant side-related differences. In addition, no significant difference was found regarding the neck-shaft angle (P = .211) and glenoid anteversion or retroversion (right, 65% [n = 33] anteversion and 35% [n = 18] retroversion; left, 69% [n = 35] anteversion and 31% [n = 16] retroversion; P = .417).

CONCLUSION

There are no significant side-dependent differences in the osseous anatomy of the glenohumeral joint. In patients with unilateral shoulder degeneration, the contralateral shoulder can provide reference values during the planning of shoulder replacement surgery.