Tomographic evaluation of Hill-Sachs lesions: is there a correlation between different methods of measurement?

Variability in quantifying the Hill-Sachs lesion: A scoping review

Background

Currently, is there no consensus on a widely accepted measurement technique for calculating the Hill-Sachs lesion (HSL). The purpose of this review is to provide an overview of the techniques and imaging modalities to assess the HSL pre-operatively.

Methods

Four online databases (PubMed, Embase, MEDLINE, and COCHRANE) were searched for literature on the various modalities and measurement techniques used for quantifying HSLs, from data inception to 20 November 2021. The Methodological Index for Non-Randomized Studies tool was used to assess study quality.

Results

Forty-five studies encompassing 3413 patients were included in this review. MRA and MRI showed the highest sensitivity, specificity, and accuracy values. Intrarater and interrater agreement was shown to be the highest amongst MRA. The most common reference tests for measuring the HSL were arthroscopy, radiography, arthro-CT, and surgical techniques.

Conclusion

MRA and MRI are reliable imaging modalities with good test diagnostic properties for assessment of HSLs. There is a wide variety of measurement techniques and imaging modalities for HSL assessment, however a lack of comparative studies exists. Thus, it is not possible to comment on the superiority of one technique over another. Future studies comparing imaging modalities and measurement techniques are needed that incorporate a cost-benefit analysis.

Assessing Bone Loss in the Unstable Shoulder: a Scoping Review

PURPOSE OF REVIEW

The aim of this scoping review is to identify and summarize findings published in the literature over the past 5 years related to methods for assessment of bone loss in anterior shoulder instability.

RECENT FINDINGS

Of the 113 clinical studies included in this review, 76 reported a cutoff for glenoid bone loss when determining the patients indicated for one of the many stabilization procedures investigated. Bone loss on the glenoid side was evaluated most commonly with three-dimensional computed tomography (3D CT), and either linear or surface area-based methods were employed with the use of a best-fit circle. When combined with plain CT, the two methods comprise up to 70% of the reported measurement techniques for glenoid bone loss (79 of 113 studies). On the humeral side, Hill-Sachs lesions were assessed more heterogeneously, though plain CT or 3D CT remained the methods of choice in the majority of studies (43 of 68, 63.2%). Lastly, the glenoid track was assessed by 27 of 113 studies (23.9%), again most commonly with 3D CT (13 studies) and plain CT (seven studies). The assessment of glenoid and humeral bone loss is essential to treatment decisions for patient with recurrent anterior shoulder instability. Glenoid bone loss is most commonly assessed using cross-sectional imaging, most often 3D CT, and some variation of a best-fit circle applied to the inferior portion of the glenoid. Hill-Sachs lesion assessment was also commonly done using three-dimensional imaging; however, there was more variability in assessment methods across studies and there is an obvious need to unify the approach to humeral bone loss assessment for the purposes of improving treatment decisions and to better assess on-track and off-track lesions.

Validação clínica do conceito de glenoid track na instabilidade glenoumeral anterior

Objective  To evaluate the correlation of the glenoid track and glenoidal bone loss with the recurrence dislocation rate and the Rowe score.

Methods  Retrospective study that assessed the glenoid track and glenoidal bone loss through preoperative magnetic resonance imaging. Patients undergoing primary arthroscopic repair of anterior Bankart were included. Patients with glenoidal bone loss greater than 21%, rotator cuff tear, scapular waist fracture, and posterior or multidirectional instability were not included. Rowe score were the primary outcome, and the recurrence rate was the secondary outcome.

Results  One hundred and two patients were included. Postoperative recurrent instability was reported by 8 patients (7.8%). Four patients (50%) in the group with recurrence presented glenoidal bone loss greater than 13.5% against 24 (25.5%) in the group without recurrence ( p  = 0.210), with a negative predictive value of 94.6%. Three patients (37.5%) in the recurrence group were considered off-track, against 13 (13.8%) in the group without recurrence ( p  = 0.109), with a negative predictive value of 94.2%. Patients with absolute glenoid track value ≤ 1.5 mm had worse results in relation to the recurrence group, with 6 patients (75%) presenting recurrence ( p  = 0.003).

Conclusion  Off-track injury and glenoidal bone loss greater than the subcritical are not related to the recurrence rate and Rowe score, despite the high negative predictive value. The cut of the absolute value of the glenoid track at 1.5 mm had a significant relationship with the recurrence rate.

Chronic locked posterior gleno-humeral dislocation: technical note on fibular grafting for restoration of humeral head sphericity

BACKGROUND

Reconstruction of reverse Hill-Sachs defect using osteo-chondral allograft has the advantages of spherical re-contouring and provision of smooth biological articular surface of the reconstructed humeral head. However, worldwide availability and risk of disease transmission of osteo-chondral allograft remain points of increasing concerns. As an alternative to lacking osteo-chondral allograft, the current technical note describes a reconstructive technique of reverse Hill-Sachs defect using autologous fibular grafting.

METHODS

Following open reduction of the dislocated humeral head, reverse Hill-Sachs defect was reconstructed using 3-4 autologous fibular pieces (each is of 10 mm in length) fixed in flush with the articular cartilage using 4-mm cancellous screws. Defect reconstruction was then followed by modified McLaughlin's transfer and posterior capsulorrhaphy.

RESULTS

Spherical contour of the humeral head and gleno-humeral range of motion were restored. Intra-operative dynamic testing of the reconstruct revealed no residual posterior gleno-humeral instability.

CONCLUSION

Currently reported technique might offer advantages of graft availability, technical simplicity, familiarity and reproducibility, safety (i.e. no disease transmission) and bone preservation facilitating future revision management (if needed). Nevertheless, long-term outcomes of this technique should be investigated via further cohort clinical studies.

Interobserver agreement for detecting Hill-Sachs lesions on magnetic resonance imaging

BACKGROUND

Our aim is to determine the interobserver reliability for surgeons to detect Hill-Sachs lesions on magnetic resonance imaging (MRI), the certainty of judgement, and the effects of surgeon characteristics on agreement.

METHODS

Twenty-nine patients with Hill-Sachs lesions or other lesions with a similar appearance on MRIs were presented to 20 surgeons without any patient characteristics. The surgeons answered questions on the presence of Hill-Sachs lesions and the certainty of diagnosis. Interobserver agreement was assessed using the Fleiss' kappa (κ) and percentage of agreement. Agreement between surgeons was compared using a technique similar to the pairwise t-test for means, based on large-sample linear approximation of Fleiss' kappa, with Bonferroni correction.

RESULTS

The agreement between surgeons in detecting Hill-Sachs lesions on MRI was fair (69% agreement; κ, 0.304; p<0.001). In 84% of the cases, surgeons were certain or highly certain about the presence of a Hill-Sachs lesion.

CONCLUSIONS

Although surgeons reported high levels of certainty for their ability to detect Hill-Sachs lesions, there was only a fair amount of agreement between surgeons in detecting Hill-Sachs lesions on MRI. This indicates that clear criteria for defining Hill-Sachs lesions are lacking, which hampers accurate diagnosis and can compromise treatment.

Anterior Instability: What to Look for

Most first-time anterior glenohumeral dislocations occur as the result of trauma. Many patients suffer recurrent episodes of anterior shoulder instability (ASI). The anatomy and biomechanics of ASI is addressed, as is the pathophysiology of capsulolabral injury. The roles of imaging modalities are described, including computed tomography (CT) and MR imaging with the additional value of arthrography and specialized imaging positions. Advances in 3D CT and MR imaging particularly with respect to the quantification of humeral and glenoid bone loss is discussed. The concepts of engaging and nonengaging lesions as well as on-track and off-track lesions are examined.

[Current concepts of diagnostic techniques and measurement methods for bone defect in patient with anterior shoulder instability]

Objective

To summarize the diagnosis and measurement methods of bone defect in anterior shoulder instability (glenoid bone defect and Hill-Sachs lesion).

Methods

The related literature on the diagnosis and measurement of the bone defect in anterior shoulder instability was reviewed and summarized.

Results

The commonly used techniques for the diagnosis of anterior glenoid bone defect and Hill-Sachs lesion of humeral head include X-ray, CT, MRI, arthroscopy, arthrography. The methods for measuring the degree of anterior glenoid bone defect include Griffith method, glenoid index method, Pico method, and best-fit circle method. The indexes for measuring the Hill-Sachs lesion include the length, width, depth, and volume. X-ray is mainly used for primary screening. Best-fit circle method on three-dimensional (3D) CT reconstruction is commonly used to measure the glenoid bone defect currently. Glenoid track theory on 3D CT reconstruction is popular in recent years. Reliability of measuring the glenoid bone defect and Hill-Sachs lesion with MRI and arthroscopy is still debatable. Arthrography is more and more used in the diagnosis of shoulder joint instability of bone defect and concomitant soft tissue injury.

Conclusion

How to improve the accuracy of evaluating glenoid bone defect and Hill-Sachs lesion before surgery still need further study.

How to measure a Hill-Sachs lesion: a systematic review

Quantifying bone loss is important to decide the best treatment for patients with recurrent anterior glenohumeral instability. Currently, there is no standard method available to make a precise evaluation of the Hill–Sachs lesion and predict its engagement before the surgical procedure. This literature review was performed in order to identify existing published imaging methods quantifying humeral head bone loss in Hill–Sachs lesions.

Searches were undertaken in Scopus and PubMed databases from January 2008 until February 2018. The search terms were “Hill-Sachs” and “measurement” for the initial search and “Hill–Sachs bone loss” for the second, to be present in the keywords, abstracts and title. All articles that presented a method for quantifying measurement of Hill–Sachs lesions were analysed.

Several methods are currently available to evaluate Hill–Sachs lesions. The length, width and depth measurements on CT scans show strong inter and intra-observer correlation coefficients. Three-dimensional CT is helpful for evaluation of bony injuries; however, there were no significant differences between 3D CT and 3D MRI measurements. The on-track off-track method using MRI allows a simultaneous evaluation of the Hill–Sachs and glenoid bone loss and also predicts the engaging lesions with good accuracy.

Cite this article: EFORT Open Rev 2019;4:151-157. DOI: 10.1302/2058-5241.4.180031

Three-dimensional computed tomography measurement accuracy of varying Hill-Sachs lesion size

BACKGROUND

The glenoid track concept has been proposed to correlate shoulder stability with bone loss. Accurate assessment of Hill-Sachs lesion size preoperatively may affect surgical planning and postoperative outcomes; however, no measurement method has been universally accepted. This study aimed to assess the accuracy and reliability of measuring Hill-Sachs lesion sizes using 3-dimensional (3D) computed tomography (CT).

METHODS

Nine polyurethane humerus bone substitutes were used to create Hill-Sachs lesions of varying sizes with a combination of lesion depth (shallow, intermediate, and deep) and width (small, medium, and large). Specimens were scanned with a clinical CT scanner for size measurements and a micro-CT scanner for measurement of true lesion size. Six evaluators repeated measurements twice in a 2-week interval. Scans were measured by use of 3D CT reconstructions for length, width, and Hill-Sachs interval and with use of 2D CT for depth. The interclass correlation coefficient evaluated interobserver and intraobserver variability and percentage error, and Student t-tests assessed measurement accuracy.

RESULTS

Interclass correlation coefficient reliability demonstrated strong agreement for all variables measured (0.856-0.975). Percentage error between measured length and measured depth and the true measurement significantly varied with respect to both lesion depth (P = .003 and P = .005, respectively) and lesion size (P = .049 and P = .004, respectively).

DISCUSSION AND CONCLUSIONS

The 3D CT imaging is effective and reproducible in determining lesion size. Determination of Hill-Sachs interval width is also reliable when it is applied to the glenoid track concept. Measured values on 3D and 2-dimensional imaging using a conventional CT scanner may slightly underestimate true measurements.

Imaging of shoulder instability

This extended review tries to cover the imaging findings of the wide range of shoulder injuries secondary to shoulder joint instability. Usefulness of the different imaging methods is stressed, including radiography, computed tomography (CT) and magnetic resonance. The main topics to be covered include traumatic, atraumatic and minor instability syndromes. Radiography may show bone abnormalities associated to instability, including developmental and post-traumatic changes. CT is the best technique depicting and quantifying skeletal changes. MR-arthrography is the main tool in diagnosing the shoulder instability injuries.

Anatomic Humeral Head Reconstruction With Fresh Osteochondral Talus Allograft for Recurrent Glenohumeral Instability With Reverse Hill-Sachs Lesion

The treatment of recurrent glenohumeral instability, especially with a concomitant bony lesion, remains challenging. This is especially true in the case of posterior instability given its less common incidence. Moreover, the presence of an engaging reverse Hill-Sachs lesion in combination with posterior instability will result in the need for a more aggressive treatment option. In comparison with a Hill-Sachs lesion, a reverse Hill-Sachs lesion features greater chondral deficiency that must be addressed during treatment. We propose the talus allograft as a potential allograft for treatment of an engaging reverse Hill-Sachs lesion. The superior articular surface of the talus may be used to reconstruct the articular surface of the humeral head. In this technical note, we describe our preferred primary technique for treatment of an engaging reverse Hill-Sachs lesion with recurrent glenohumeral instability through use of a fresh osteochondral talus allograft, as well as discuss the advantages and disadvantages of this allograft option.