Quantification of dynamic posterior translation in modified bilateral Alexander views and correlation with clinical and radiological parameters in patients with acute acromioclavicular joint instability
Abstract:Measuring the OL is a convenient way for quantifying DPT in modified Alexander views. It showed significant correlation with clinical scores, indicating the relevance of DPT in patients with AC-joint injury.
“…3 . The acromial centre line to dorsal clavicle (AC–DC) and centre cranialization (CCran) for vertical displacement, and maximal overlap (OL) [ 15 ], lateral extension (LE) and the glenoid centre line to posterior clavicle (GC–PC) for horizontal displacement. Fig.…”
PurposeThe aim of this study was to identify the most accurate and reliable quantitative radiographic parameters for assessing vertical and horizontal instability in different Rockwood grades of acromioclavicular joint (ACJ) separations. Furthermore, the effect of projectional variation on these parameters was investigated in obtaining lateral Alexander view radiographs.MethodsA Sawbone model of a scapula with clavicle was mounted on a holding device, and acromioclavicular dislocations as per the Rockwood classification system were simulated with the addition of horizontal posterior displacement. Projectional variations for each injury type were performed by tilting/rotating the Sawbone construct in the coronal, sagittal or axial plane. Radiographic imaging in the form of an anterior–posterior Zanca view and a lateral Alexander view were taken for each injury type and each projectional variation. Five newly defined radiographic parameters for assessing horizontal and vertical displacement as well as commonly used coracoclavicular distance view were measured. Reliability, validity and the effect of projectional variation were investigated for these radiographic measurements.ResultsAll radiographic parameters showed excellent intra- and interobserver reliability. The validity was excellent for the acromial centre line to dorsal clavicle (AC–DC) in vertical displacement and for the glenoid centre line to posterior clavicle (GC–PC) in horizontal displacement, whilst the remaining measurements showed moderate validity. For AC–DC and GC–PC, convergent validity expressed strong correlation to the effective distance and discriminant validity demonstrated its ability to differentiate between various grades of ACJ dislocations. The effect of projectional variation increased with the degree of deviation and was maximal (3 mm) for AC–DC in 20° anteverted malpositioning and for GC–PC in 20° retroverted malpositioning.ConclusionsAC–DC and the GC–PC are two novel quantitative radiographic parameters of vertical and horizontal instability in ACJ dislocations that demonstrate excellent reliability and validity with reasonable inertness to malpositioning. The use of AC–DC for assessing vertical displacement and GC–PC for assessing horizontal displacement in a single Alexander view is recommended to guide the appropriate management of ACJ dislocations. A better appreciation of the degree of horizontal instability, especially in lower Rockwood grades (II, III) of ACJ dislocations, may improve management of these controversial injuries.
“…3 . The acromial centre line to dorsal clavicle (AC–DC) and centre cranialization (CCran) for vertical displacement, and maximal overlap (OL) [ 15 ], lateral extension (LE) and the glenoid centre line to posterior clavicle (GC–PC) for horizontal displacement. Fig.…”
PurposeThe aim of this study was to identify the most accurate and reliable quantitative radiographic parameters for assessing vertical and horizontal instability in different Rockwood grades of acromioclavicular joint (ACJ) separations. Furthermore, the effect of projectional variation on these parameters was investigated in obtaining lateral Alexander view radiographs.MethodsA Sawbone model of a scapula with clavicle was mounted on a holding device, and acromioclavicular dislocations as per the Rockwood classification system were simulated with the addition of horizontal posterior displacement. Projectional variations for each injury type were performed by tilting/rotating the Sawbone construct in the coronal, sagittal or axial plane. Radiographic imaging in the form of an anterior–posterior Zanca view and a lateral Alexander view were taken for each injury type and each projectional variation. Five newly defined radiographic parameters for assessing horizontal and vertical displacement as well as commonly used coracoclavicular distance view were measured. Reliability, validity and the effect of projectional variation were investigated for these radiographic measurements.ResultsAll radiographic parameters showed excellent intra- and interobserver reliability. The validity was excellent for the acromial centre line to dorsal clavicle (AC–DC) in vertical displacement and for the glenoid centre line to posterior clavicle (GC–PC) in horizontal displacement, whilst the remaining measurements showed moderate validity. For AC–DC and GC–PC, convergent validity expressed strong correlation to the effective distance and discriminant validity demonstrated its ability to differentiate between various grades of ACJ dislocations. The effect of projectional variation increased with the degree of deviation and was maximal (3 mm) for AC–DC in 20° anteverted malpositioning and for GC–PC in 20° retroverted malpositioning.ConclusionsAC–DC and the GC–PC are two novel quantitative radiographic parameters of vertical and horizontal instability in ACJ dislocations that demonstrate excellent reliability and validity with reasonable inertness to malpositioning. The use of AC–DC for assessing vertical displacement and GC–PC for assessing horizontal displacement in a single Alexander view is recommended to guide the appropriate management of ACJ dislocations. A better appreciation of the degree of horizontal instability, especially in lower Rockwood grades (II, III) of ACJ dislocations, may improve management of these controversial injuries.
“…24,37 Injuries to this ligament lead to horizontal instability of the AC joint and are often neglected or underdiagnosed, which can cause chronic AC joint injuries and poor patient outcomes in terms of pain and disability. 13,29,31,42 Horizontal instability is difficult to quantify by use of standard radiographs, which may complicate the diagnosis. 13,26,31,35,37,44,49 Despite the poor clinical outcomes associated with horizontal instability, most of the published surgical techniques for AC joint reconstruction address only the vertical component of instability.…”
Background: Injuries to the acromioclavicular (AC) joint are common and should be suspected in patients who have shoulder pain in the region of the acromion and clavicle. Injuries to the AC ligament can cause horizontal instability and are often neglected or underdiagnosed, which can lead to poor patient outcomes. Purpose: To perform a systematic review of the literature on the diagnosis and treatment of horizontal instability of the AC joint. Study Design: Systematic review. Methods: The authors performed a systematic review using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed and EMBASE were searched for studies that investigated diagnosis, treatment, and failure of operative management of acute and chronic AC separations. Studies that did not specifically evaluate AC joint injuries, were not written in English, or were specific only to vertical instability of the AC joint were excluded. Results: Overall, 23 articles met the inclusion criteria and were therefore included in this systematic review. Diagnosing horizontal AC instability is difficult using plain radiographs; dynamic views were shown in some cases to better detect horizontal instability than with static views. More than 60 procedures for treating AC joint injuries have been published, but many focus on vertical rather than horizontal instability. Modifications to current surgical procedures to incorporate reconstruction of the horizontal component showed improved patient outcomes. Such modifications included additional AC joint suture cord cerclage, combined AC and coracoclavicular ligament reconstruction, and the Twin Tail TightRope triple button technique. Failure after surgical stabilization of AC joint separation has been reported to occur in 15% to 80% of cases. Conclusion: No consensus is available regarding the best practices for diagnosis, evaluation, and treatment of acute or chronic horizontal instability of the AC joint. Moreover, horizontal instability injuries are often neglected or poorly understood, making diagnosis difficult, which may lead to high complication rates and failure after surgical stabilization.
“…Furthermore, recently a very promising quantification method for Alexander views was proposed by Minkus et al that involves measuring the overlapping length of the acromion and clavicle et al. [ 11 ]. We did not apply this method in our study.…”
BackgroundAcute acromioclavicular (AC) dislocation is classified according to Rockwood (RW). Although of clinical relevance, dynamic horizontal translation (DHT) is not listed in this classification or in frequently used clinical evaluation tools. The aim of this study was (a) to evaluate vertical and horizontal AC joint instabilities and assess their combined occurrence and clinical appearance in a consecutive group of patients, as well as (b) to develop a new classification of acute AC joint dislocation.MethodA consecutive group of 61 patients (seven female, 54 male) with a mean age of 34.5 years (18.9–60.1) were included in the study. All patients underwent posttraumatic clinical—Taft Score (TF), Acromioclavicular Joint Instability Score (ACJI), Constant Score (CS), Subjective Shoulder Value (SSV)—and radiological (bilateral anteroposterior stress and bilateral Alexander views) evaluation.ResultsAccording to the RW classification, the following AC dislocations were present: eight (13.1%) type I, nine (14.8%) type II, 22 (36.1%) type III, and 22 (36.1%) type V. Based on the clinical and radiographic results, a new classification is proposed: Type I instabilities show only a partial vertical displacement (≤30% coracoclavicular distance [CCD]) and type II a complete vertical displacement (>30% CCD). Both type I and II are further graded into none or partial (A) and complete DHT (B) as seen on bilateral Alexander views.ConclusionDHT can be found in low-grade instabilities and lead to inferior clinical results in the posttraumatic situation.
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