Repair of an anteroinferior glenoid defect by the latarjet procedure: quantitative assessment of the repair by computed tomography

Size and morphology of the coracoid and glenoid in pediatric and adolescent patients: implications for Latarjet procedure

Background

Glenohumeral instability is a challenging problem in children and adolescents. For patients with anterior glenoid bone loss, the Latarjet procedure is an effective treatment option. However, concerns about coracoid size and morphology may limit its utilization within this patient population. The purpose of this study was to establish normative data on coracoid and glenoid size and morphology among a large cohort of adolescent patients and describe the anatomic relationships with demographic factors.

Methods

This is a retrospective cross-sectional study of a consecutive series of 584 patients aged 12-21 years after a chest computed tomography scan for non-shoulder related trauma at a single level I trauma center. Demographic characteristics were collected from the electronic medical record, and the following coracoid anatomic measurements were obtained from computed tomography scans: coracoid length, coracoid thickness, coracoid width, glenoid height, and glenoid width. The ratio of coracoid thickness to glenoid width was calculated to estimate the percent bone loss that could be addressed with a traditional Latarjet coracoid transfer. To ensure reliability among 3 reviewers, all measured the same 25 scans and inter-rater reliability was excellent with all Kappa coefficients >0.81. The remaining scans were divided equally and assessed separately by these reviewers. Correlation coefficients were used to quantify the relationships between all anatomic measures and the age, weight, and height of individuals. Growth curves for each measurement were modeled using quantile regression with height and height∗height as predictors. Additionally, we stratified the growth curves by sex, when significant. Of the 584 subjects, 55% were male, and average age was 19 years (range 12, 21).

Results

All growth curves illustrated increase anatomic size across the height range of 145-190 cm. The growth curve including all patients (Fig. 1) illustrated that the 50% percentile of median coracoid length increased from approximately 28 to 32 mm. In addition to height, sex was a significant predictor for coracoid width and glenoid width. The median coracoid width increased from approximately 9.5 to 10.2 mm for females compared to an increased width from approximately 10 to 11 mm for males. The median glenoid width for females increased from approximately 21 to 25 mm and for males the median glenoid width increased from just under 22 to 25.5 mm.

Conclusions

Among children and adolescents, coracoid and glenoid size are correlated with patient height. These data can help guide patient selection for the Latarjet procedure.

Long-term prevalence and impact of glenohumeral osteoarthritis after Latarjet-Patte procedure for anterior instability

INTRODUCTION

The Latarjet procedure provides satisfactory functional results, with low rates of recurrence. It is, however, sometimes claimed to induce osteoarthritis due to the positioning of the bone-block and hardware. The aims of the present study were to assess the long-term prevalence of osteoarthritis following the procedure, to determine risk factors and assess clinical impact. The study hypothesis was that osteoarthritis risk can be reduced by good bone-block positioning. The secondary objective was to assess long-term recurrence of instability.

MATERIALS AND METHODS

Out of a cohort of 102 patients (106 shoulders) operated on between 1984 and 1998, 77 had complete radiology files for analysis in a previous study published in 2003. Forty-four of these patients were seen again for clinical and radiological assessment at a mean 22 years' follow-up, to be compared to results previously reported at 8 years. Clinical assessment comprised range of motion and Constant and Walch-Duplay scores. X-rays were taken systematically to determine Samilson osteoarthritis stage; 31 patients also underwent CT.

RESULTS

In the 44 patients, the rate of osteoarthritis was 34.1%. 90.9% of patients were satisfied. Mean Constant score was 83.5±14 and mean Walch-Duplay score was 71.6±23.4. Advanced age at surgery and at assessment, length of follow-up and age >30 years at first episode of instability were the main factors for onset of osteoarthritis, independently of surgery. Lateral bone-block overhang correlated with onset of osteoarthritis: 71.4%, versus 16.7% in medial or flush bone-block (p=0.0004). Humeral notch, glenoid bone defect and number of preoperative episodes of instability were unrelated to onset of osteoarthritis. Lateral bone-block overhang was the only risk factor related to surgery. The clinical impact of the osteoarthritis was significant only in advanced stages (Samilson 3 and 4).

CONCLUSION

Lateral bone-block overhang was the only surgical risk factor for osteoarthritis in the long-term. Strict coracoid positioning is therefore essential, and could be facilitated by specific instrumentation and by arthroscopy.

LEVEL OF EVIDENCE

IV; retrospective study.

Biomechanical Analysis of Plate Fixation Compared With Various Screw Configurations for Use in the Latarjet Procedure

Background:

The biomechanical properties of coracoid fixation with a miniplate during the Latarjet procedure have not been described.

Purpose:

To determine the biomechanical properties of miniplate fixation for the Latarjet procedure compared with various screw fixation configurations.

Study Design:

Controlled laboratory study.

Methods:

A total of 8 groups (n = 5 specimens per group) were tested at a screw insertion angle of 0°: (1) 3.75-mm single screw, (2) 3.75-mm double screw, (3) 3.75-mm double screw with washers, (4) 3.75-mm double screw with a miniplate, (5) 4.00-mm single screw, (6) 4.00-mm double screw, (7) 4.00-mm double screw with washers, and (8) 4.00-mm double screw with a miniplate. In addition, similar to groups 1 to 3 and 5 to 7, there were 30 additional specimens (n = 5 per group) tested at a screw insertion angle of 15° (groups 9-14). To maintain specimen uniformity, rigid polyurethane foam blocks were used. Testing parameters included a preload of 214 N for 10 seconds, cyclical loading from 184 to 736 N at 1 Hz for 100 cycles, and failure loading at a rate of 15 mm/min until 10 mm of displacement or specimen failure occurred.

Results:

All single-screw constructs and 77% of 15° screw constructs failed before the completion of cyclical loading. Across all groups, group 8 (4.00-mm double screw with miniplate) demonstrated the highest maximum failure load (P < .001). There were no differences in failure loads among specimens with single-screw fixation (groups 1, 5, 9, and 12; P > .05). All specimens in groups 9, 10, 11, 12, 13, and 14 (insertion angle of 15°) had significantly lower maximum failure loads compared with specimens in groups 2, 3, 4, 6, 7, and 8 (insertion angle of 0°) (P < .001 for all).

Conclusion:

These results indicate significantly superior failure loads with the miniplate compared with all other constructs. Across all fixation techniques and screw sizes, constructs with screws inserted at 0° performed better than constructs with screws inserted at 15°.

Clinical Relevance:

The use of a miniplate for coracoid fixation during the Latarjet procedure may provide a more durable construct for the high-demand contact athlete.

Open Versus Arthroscopic Latarjet Procedure for the Treatment of Chronic Anterior Glenohumeral Instability With Glenoid Bone Loss

PURPOSE

The purpose of this study was to compare the clinical, functional, and radiographic outcomes of open versus arthroscopic Latarjet procedures.

METHODS

Between December 2009 to January 2015, all patients older than 18 years of age who were treated with a Latarjet procedure for chronic osseous anterior instability by a single surgeon were included in this retrospective cohort study. Range of motion, strength, Rowe, Western Ontario Shoulder Instability Index (WOSI) scores, and pain level according to the Visual Analog Scale (VAS) were evaluated. In addition, postoperative computed tomography scans were used to evaluate the position of the transferred coracoid, screw orientation, and degree of graft resorption.

RESULTS

Forty-eight patients with a mean age of 29.5 years (range 19-59 years) who underwent open (n = 15; group OL) and arthroscopic (n = 33; group AL) Latarjet procedures were included in the study. The mean follow-up was 30.5 months (range 24-50 months). At final follow-up there were significant differences in the mean internal rotation loss (mean of 9° vs 14°, P = .044) favoring open surgery and WOSI (P = .017) scores favoring arthroscopic. No significant differences were detected in mean forward flexion loss (P = .918), external rotation loss (P = .883), Rowe (P = .429), and Visual Analog Scale (P = .208) scores. Mean superoinferior position of the coracoid bone graft was found between the 1:55 and 4:49 o'clock positions (2:05-4:55 for group OL; 1:51-4:47 for group AL) in en-face views. The grafts were placed laterally in 13% (group OL) and 9% (group AL) of patients. The mean α angles of the screws were 11° and 19.2°, respectively (P = .004). The mean graft resorption rates were 21% and 34% (P = .087), respectively.

CONCLUSION

Good functional results were obtained after both open and arthroscopic Latarjet procedures for the treatment of chronic osseous anterior shoulder instability. Comparative analysis showed small but statistically significant differences in internal rotation loss favoring open and in WOSI favoring arthroscopic techniques. All measured radiographic parameters were similar with the exception of a significant difference in alpha angle with improved screw position in open surgery. OL and AL techniques provide similar clinical and radiographic outcomes.

LEVEL OF EVIDENCE

III; Retrospective cohort study with comparison group.

Best implant choice for coracoid graft fixation during the Latarjet procedure depends on patients' morphometric considerations

PURPOSE

To assess the anthropometric dimensions of the coracoid process and the glenoid articular surface and to determine possible implications with the different commercially available Latarjet fixation techniques.

METHODS

In a total of 101 skeletal scapulae the glenoid length (GL), the glenoid width (GW), the coracoid length (CL), the coracoid width (CW) and the coracoid thickness (CTh) were measured. In order to assess the ability of the transferred coracoid to restore the glenoid anatomy we created a hypothetical model of 10%, 15%, 20%, 25% and 30% glenoid bone loss. We analyzed four common surgical fixation techniques for the Latarjet procedure (4.5 mm screws, 3.75 mm screws, 3.5 mm screws, and 2.8 mm button). The distances from the superior-inferior and medio-lateral limits of the coracoid using the four different fixation methods were calculated. We hypothesized that the "safe distance" between the implant and the coracoid osteotomy should be at least equal to the diameter of the implant.

RESULTS

The intra and inter-observer reliability tests were almost perfect for all measurements. The mean GH was 36.8 ± 2.5 mm, the GW 26.4 ± 2.2 mm, the CL 23.9 ± 3 mm, the CW 13.6 ± 2.mm, and the mean CTh was 8.7 ± 1.3 mm. The CL was < 25 mm in 46% of the cases. In cases with 25% and 30% bone loss, the coracoid graft restored the glenoid anatomy in 96% and 79.2% of the cases. With the use of the 4.5 mm screws the "safe distance" was present in 56% of the cases, with the 3.75 mm screws in 85%, with the 3.5 mm screws in 87%, and with the 2.8 mm button in 98% of the cases. The distance from the medio-lateral limit of the coracoid could be significantly increased (up to 9 mm) when smaller-button implants are used.

CONCLUSIONS

The coracoid graft could not always restore glenoid defects of 30%. Larger implants could be positioned too close to the osteotomy and the "medio-lateral offset" of the coracoid could be increased with smaller implants.

Relationship between the Thickness of the Coracoid Process and Latarjet Graft Positioning-An Anatomical Study on 70 Embalmed Scapulae

Background: The Latarjet procedure is a popular technique with the aim of the reconstruction of glenoid cavity bone defects in patients with chronic anterior shoulder instability. Studies have shown that the Congruent arc Latarjet procedure is better able to reconstruct larger defects than the Classic Latarjet, but there is a lack of information on the limitations of both methods. Methods: The dimensions of the glenoid width and the native coracoid process of two groups with 35 Formol-Carbol embalmed scapulae each were measured using a digital caliper. The relationship between the coracoid graft and the anterior-posterior diameter of the glenoid cavity was calculated to determine the maximum defect size of the glenoid cavity width, which can be treated by both Latarjet techniques. Results: The average restorable defect size of the anterior segment of the glenoid cavity was 28.4% ± 4.6% (range 19.2%–38.8%) in the Classic Latarjet group, and 45.6% ± 5.2% (range 35.7%–57.1%) in the Congruent arc Latarjet group. Based on our results, the feasibility of the Classic Latarjet procedure to reconstitute the anatomical width of the glenoid cavity was 86% in a 25% bone loss scenario, and only 40% in a 30% bone loss scenario. Conclusion: Based on our results we are unable to define a clear threshold for the optimal Latarjet graft position. In glenoid cavity defects <20%, the Classic Latarjet technique usually provides enough bone stock for anatomical reconstruction. Defects ≥35% of the glenoid cavity width should only be treated with a coracoid graft in the Congruent arc position. In the critical area between 20% and 35% of bone loss, we suggest the preoperative assessment of coracoid dimensions, based on which the graft position can be planned to restore the anatomical anterior-posterior diameter of the glenoid cavity.

Bone block procedures for glenohumeral joint instability

Glenoid bone loss is a well established cause of instability and long term morbidity if not adequadely addressed. Anterior glenohumeral instability due an anterior glenoid defect is significantly more common, and for many years has been well treated with open anterior bone block augmentation procedures, most commonly the latarjet procedure. However, with refinement of this technique and some interest in reducing morbidity associated with iliac crest bone harvest, arthroscopic bone block procedures with allograft has become more popular. In this article we will review some of the key available evidence. We will also review management of the less common and more challenging posterior glenoid defects associated with posterior instability.

Arthroscopic Versus Open Iliac Crest Bone Grafting in Recurrent Anterior Shoulder Instability With Glenoid Bone Loss: A Computed Tomography-Based Quantitative Assessment

PURPOSE

To assess the iliac crest bone graft (ICBG) position in the en-face view and axial plane comparing arthroscopic with open procedures.

METHODS

A total of 40 consecutive patients with recurrent anterior shoulder instability and glenoid bone loss over 10% treated by 2 independent orthopaedic departments were included. Two independent observers analyzed preoperative and immediate postoperative computed tomography scans of 20 open (group O) and 20 arthroscopic (group A) procedures. Defect and ICBG characteristics of the J-shaped graft in the en-face view and axial plane were manually assessed by multiplanar reconstructed computed tomography scans. Variances in terms of graft positioning were analyzed.

RESULTS

No significant variances in arthroscopic graft positioning were observed. The graft position in the en-face view was comparable in both groups, with the superior extent of the arthroscopic graft (40° ± 9° [inferior extent, 139° ± 16°]) lying significantly higher than the superior extent in group O (50° ± 13°, P = .005 [inferior extent, 147° ± 21°; P = .178]). The covered glenoid defect size was above 95% (98% ± 1% in group O vs 95% ± 2% in group A, P = .001). The arthroscopic graft in the axial plane showed a significantly steeper impaction angle (34.8° ± 7.8° vs 26.9° ± 9.9°, P = .010), with a significantly increased medial offset compared with group O (6.6 ± 1.7 mm vs 5.4 ± 1.3 mm, P = .024). The mediolateral step formation, however, was not significantly different (2.9 ± 1.1 mm in group A vs 3.2 ± 0.8 mm in group O, P = .289). The interobserver reliability was very good for all measurements (R = 0.969; 95% confidence interval, 0.965-0.972).

CONCLUSIONS

Positioning of the arthroscopic ICBG in the en-face view and axial plane is comparable to that of the open technique. Good glenoid defect coverage and glenoid concavity reconstruction can be achieved with the arthroscopic technique. The main difference compared with the open procedure is the significantly steeper impaction angle.

LEVEL OF EVIDENCE

Level III, case-control study.

Long Term Outcomes of Arthroscopic Shoulder Instability Surgery

BACKGROUND

Anterior shoulder instability has been successfully managed arthroscopically over the past two decades with refined "anatomic" reconstruction procedures involving the use of anchors for the repositioning and re-tensioning of the antero-inferior capsuloligamentous complex, in an effort to recreate its "bumper effect".

METHODS

Research and online content related to arthroscopic treatment of shoulder instability was reviewed and their results compared.

RESULTS

The short- and mid-term results of this technique have been very satisfactory. The greatest number of recent reports suggests that long-term results (>5 years follow-up) remain rather satisfactory, especially in the absence of significant glenoid bone loss (>20-25%). In these studies recurrent instability, in the form of either dislocation or subluxation, ranges from 5.1 to over 20%, clinical scores, more than 5 years after the index procedure, remain good or excellent in >80% of patient population as do patient satisfaction and return to previous level of activities. As regards arthroscopic non-anatomic bony procedures (Latarjet or Bristow procedures) performed in revision cases or in the presence of >20-25% bone loss of the anteroinferior aspect of the glenoid, recent reports suggest that their long-term results are very satisfactory both in terms of re-dislocation rates and patient satisfaction.

CONCLUSION

It appears that even "lege artis" performance of arthroscopic reconstruction decelerates but does not obliterate the degenerative procedure of dislocation arthropathy. The presence and grade of arthritic changes correlate with the number of dislocations sustained prior to the arthroscopic intervention, the number of anchors used and the age at initial dislocation and surgery. However, the clinical significance of radiologically evident dislocation arthropathy is debatable.

Anatomical study of the coracoid process in Mongolian male cadavers using the Latarjet procedure

Background

The Latarjet procedure addresses recurrent anterior shoulder instability in the context of a significant bony defect. However, the bony and soft tissue anatomy of the coracoid in coracoid transfer procedures has not yet been defined in Mongolian men. The aims of this study were to describe the soft tissue attachments of the coracoid regarding the bony anatomy, define the average amount of bone available for coracoid transfer, analyze the characteristics of the pectoralis minor and coracoid, and study the relationship between the bony dimensions of the coracoid and body length in Mongolian men.

Methods

We dissected 30 shoulders from 15 male Mongolian cadavers, exposing the coracoid process and attached anatomical structures including the lateral clavicle and acromion, then measured the bony dimensions of the coracoid and the locations and sizes of the coracoid soft tissue footprints.

Results

The mean length of the coracoid available for transfer was 23.93 ± 2.32 mm. The mean length of the coracoid was 42.10 ± 2.3 mm, and the mean width and height of the coracoid midpoint were 15.29 ± 1.70 mm and 11.61 ± 1.98 mm, respectively. The pectoralis minor was part of the joint capsule and passed over the coracoid in some samples. The mutation rate of the pectoralis minor footprint, which was asymmetrical and irregular, was 23.33 %. Statistical analysis involved a multiple linear regression equation.

Conclusions

The average amount of bone available for use in coracoid transfer in Mongolian men was less than that of other populations. Mutation of the pectoralis minor may induce intraoperative capsule injury because this muscle passes over the coracoid deep to the joint capsule of the glenohumeral joint and constitutes part of the shoulder joint, strengthening the joint. Statistically, higher coracoids appeared in shorter patients and longer coracoids appeared in taller patients. Surgically, great care should be taken to consider a patient’s height to precisely implement the congruent-arc Latarjet technique.

Coracoid graft positioning in the Latarjet procedure

PURPOSE

The success of shoulder stabilization with the Latarjet procedure depends on the correct positioning of the coracoid graft at the glenoid. The aim of this study was to assess intra-observer reproducibility and inter-observer reproducibility of a new standardized CT scan analysis for coracoid graft positioning in the axial plane after the Latarjet procedure and to assess the positioning in the study group.

METHODS

A consecutive series of 27 patients (22 men, 5 woman, 26.1 ± 6.4 years-13 right, 14 left shoulders) were followed up with CT scans between 2010 and 2012. The analysis of the CT scans (2.4 ± 0.7 months postoperatively) was performed with Osirix™ software. The assessment included two criteria in the axial plane: relation of the graft to the articular surface of the glenoid and impingement of the graft with the maximal humeral head circumference. Grafts were judged to be lateral, congruent, flush or medial. The strength of intra-observer agreement and inter-observer agreement was measured by the Kappa coefficient.

RESULTS

The Kappa coefficient for intra-observer agreement was "substantial" (K = 0.64 ± 0.14, z = 4.6) to "almost perfect" (K = 0.81 ± 0.14, z = 5.7). The Kappa coefficient for inter-observer variability was "substantial" (K = 0.59 ± 0.14, z = 4.3) to "almost perfect" (K = 0.89 ± 0.14, z = 6.0). In our study, in the axial plane, 3 (11 %) transplants were lateral; 6 (22 %) transplants were congruent; 16 (60 %) flush and 2 (7 %) medial.

CONCLUSION

This standardized CT scan analysis after Latarjet procedure has shown to accurately describe graft positioning in the axial plane with both good intra-observer reproducibility and inter-observer reproducibility.

LEVEL OF EVIDENCE

Case series, treatment study, Level IV.

Arthroscopic Latarjet procedure: is optimal positioning of the bone block and screws possible? A prospective computed tomography scan analysis

HYPOTHESIS

We hypothesized that the arthroscopic Latarjet procedure could be performed with accurate bone block positioning and screw fixation with a similar rate of complications to the open Latarjet procedure.

METHODS

In this prospective study, 105 shoulders (104 patients) underwent the arthroscopic Latarjet procedure performed by the same senior surgeon. The day after surgery, an independent surgeon examiner performed a multiplanar bidimensional computed tomography scan analysis. We also evaluated our learning curve by comparing 2 chronologic periods (30 procedures performed in each period), separated by an interval during which 45 procedures were performed.

RESULTS

Of the 105 shoulders included in the study, 95 (90.5%) (94 patients) were evaluated. The coracoid graft was accurately positioned relative to the equator of the glenoid surface in 87 of 95 shoulders (91.5%). Accurate bone-block positioning on the axial view with "circle" evaluation was obtained for 77 of 95 shoulders (81%). This procedure was performed in a lateralized position in 7 of 95 shoulders (7.3%) and in a medialized position in 11 shoulders (11.6%). The mean screw angulation with the glenoid surface was 21°. One patient had transient axillary nerve palsy. Of the initial 104 patients, 3 (2.8%) underwent revision. The analysis of our results indicated that the screw-glenoid surface angle significantly predicted the accuracy of the bone-block positioning (P = .001). Our learning curve estimates showed that, compared with our initial period, the average surgical time decreased, and the risk of lateralization showed a statistically significant decrease during the last period (P = .006).

CONCLUSIONS

This study showed that accurate positioning of the bone block onto the anterior aspect of the glenoid is possible, safe, and reproducible with the arthroscopic Latarjet procedure without additional complications compared with open surgery.

Imaging methods for quantifying glenoid and Hill-Sachs bone loss in traumatic instability of the shoulder: a scoping review

Background

Glenohumeral instability is a common problem following traumatic anterior shoulder dislocation. Two major risk factors of recurrent instability are glenoid and Hill-Sachs bone loss. Higher failure rates of arthroscopic Bankart repairs are associated with larger degrees of bone loss; therefore it is important to accurately and reliably quantify glenohumeral bone loss pre-operatively. This may be done with radiography, CT, or MRI; however no gold standard modality or method has been determined. A scoping review of the literature was performed to identify imaging methods for quantifying glenohumeral bone loss.

Methods

The scoping review was systematic in approach using a comprehensive search strategy and standardized study selection and evaluation. MEDLINE, EMBASE, Scopus, and Web of Science were searched. Initial selection included articles from January 2000 until July 2013, and was based on the review of titles and abstracts. Articles were carried forward if either reviewer thought that the study was appropriate. Final study selection was based on full text review based on pre-specified criteria. Consensus was reached for final article inclusion through discussion amongst the investigators. One reviewer extracted data while a second reviewer independently assessed data extraction for discrepancies.

Results

Forty-one studies evaluating glenoid and/or Hill-Sachs bone loss were included: 32 studies evaluated glenoid bone loss while 11 studies evaluated humeral head bone loss. Radiography was useful as a screening tool but not to quantify glenoid bone loss. CT was most accurate but necessitates radiation exposure. The Pico Method and Glenoid Index method were the most accurate and reliable methods for quantifying glenoid bone loss, particularly when using three-dimensional CT (3DCT). Radiography and CT have been used to quantify Hill-Sachs bone loss, but have not been studied as extensively as glenoid bone loss.

Conclusions

Radiography can be used for screening patients for significant glenoid bone loss. CT imaging, using the Glenoid Index or Pico Method, has good evidence for accurate quantification of glenoid bone loss. There is limited evidence to guide imaging of Hill-Sachs bone loss. As a consensus has not been reached, further study will help to clarify the best imaging modality and method for quantifying glenohumeral bone loss.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-015-0607-1) contains supplementary material, which is available to authorized users.

Quantitative assessment of the latarjet procedure for large glenoid defects by computed tomography: a coracoid graft can sufficiently restore the glenoid arc

BACKGROUND

Coracoid transfer to a large glenoid defect is considered an excellent method to restore the surface area of the anteroinferior glenoid. However, there is little quantitative evidence supporting whether a coracoid graft can sufficiently restore the glenoid arc.

PURPOSE

To assess whether the Latarjet procedure can sufficiently restore the surface area of the glenoid.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 44 patients who underwent a Latarjet operation for a large glenoid defect between February 2009 and July 2011 were enrolled in this study. Three-dimensional computed tomography was used to calculate the surface areas of the preoperative glenoid defect size and the reconstructed glenoid. Preoperative and postoperative clinical results also were assessed.

RESULTS

At the last follow-up, the mean visual analog scale score for instability during motion improved significantly from 5.1 points (range, 3-10 points) preoperatively to 1.3 points (range, 0-4 points) (P<.001). The mean deficit in external rotation at the side, external rotation at 90° of abduction, and internal rotation to the posterior were 10°±20°, 7°±16°, and 1.9°±4°, respectively (P=.004, .022, and .009, respectively). The overall recurrence rate was 4.5% (2 of 44 shoulders). The mean preoperative glenoid defect size was 157±38 mm2 (range, 141-239 mm2; 25.3%±6% of the intact glenoid surface). The mean surface area of the coracoid graft used for reconstruction was 152±34 mm2 (range, 146-236 mm2; 24.8%±5% of the intact glenoid surface). After the Latarjet procedure, the mean surface area of the reconstructed glenoid was 706±32 mm2 (range, 639-749 mm2). Finally, postoperative glenoid defect size was 5±11 mm2 (range, 3-28 mm2; 1.5%±2% of the intact glenoid surface).

CONCLUSION

The Latarjet procedure can provide satisfactory outcomes, including a low recurrence rate and reliable functional recovery. Defects at the anteroinferior glenoid were restored to nearly normal after coracoid transfer by use of the Latarjet procedure, which is an anatomically matched reconstruction.

Comparison of reconstructive procedures for glenoid bone loss associated with recurrent anterior shoulder instability

HYPOTHESIS

A tibial plafond allograft, iliac crest allograft, and coracoid autograft in a congruent arc Latarjet reconstruction better restore radius of curvature, depth, and surface area for glenoid bone loss in recurrent instability compared with the coracoid autograft in a standard Latarjet reconstruction for anteroinferior glenoid bone loss of the shoulder.

METHODS

Three-dimensional shoulder models were generated from bilateral computed tomography scans in 15 patients, who were a mean (standard deviation [SD]) age of 23 (7.7) years, with recurrent anterior shoulder instability and known glenoid bone loss. The surface areas of the glenoid in the involved and contralateral normal shoulder were measured. Virtual surgery was then performed using standard and congruent arc Latarjet reconstruction, tibial plafond, and iliac crest allografts. Grafts were optimally positioned to restore articular congruity and defect fill. Radius of curvature and restoration of glenoid depth were compared with the contralateral glenoid.

RESULTS

Glenoid surface area (11.04% [6.95% SD]) and depth (0.75 [0.57 SD] vs 1.44 [0.65 SD] mm) were significantly reduced (P < .012) in the injured glenoid. The mean (SD) coronal plane radius of curvature of the congruent arc Latarjet reconstruction (60.3 [39.0 SD] mm) more closely matched the radius of curvature of the injured glenoid (67.5 [33.2 SD] mm) compared with the other grafts. Restored glenoid depth was greater in the tibial plafond (1.8 [1.1 SD] mm) and iliac crest (2.0 [0.6 SD] mm) allografts compared with other grafts (P < .002).

CONCLUSION

Congruent arc Latarjet reconstruction more closely restores native glenoid coronal radius of curvature, whereas tibial plafond and iliac crest allografts more adequately restore depth compared with standard Latarjet reconstruction.

What's new in the use of MRI in the orthopaedic trauma patient?

MRI has been established as an essential tool for accurate diagnosis in patients with musculoskeletal trauma. Its major advantages include excellent soft tissue contrast, high spatial resolution and lack of ionizing radiation. Although plain radiographs remain the basic tool for diagnosis and treatment planning in bone fractures assisted by CT in pelvic, spine and large joints injuries, there are specific circumstances that require MRI. For instance, tendinous, ligamentous, intraarticular structures such as the cartilage and menisci, and intramedullary injury are seen mostly with MRI. Volumetric 3D techniques are now commercially available and provide higher spatial resolution which improves anatomic detail, allows multiplanar reformations and reduces the acquisition time. Newer applications on quantitative rather than morphologic imaging, such as relaxometry and diffusion tensor imaging, may be of paramount importance in treatment planning in the near future. Software improvements reduce metal induced artefacts, allowing thus imaging of the postoperative patient with metallic implants. A tendency towards a structured reporting pattern and standardised medical communication needs to be further explored for the benefit of orthopaedic surgeons, radiologists and patients.

Validity of arthroscopic measurement of glenoid bone loss using the bare spot

PURPOSE

Our aim was to test the validity of using the bare spot method to quantify glenoid bone loss arthroscopically in patients with shoulder instability.

METHODS

Twenty-seven patients with no evidence of instability (18 males, nine females; mean age 59.1 years) were evaluated arthroscopically to assess whether the bare spot is consistently located at the center of the inferior glenoid. Another 40 patients with glenohumeral anterior instability who underwent shoulder arthroscopy (30 males, ten females; mean age 25.9 years) were evaluated for glenoid bone loss with preoperative three-dimensional computed tomography (3D-CT) and arthroscopic examination. In patients without instability, the distances from the bare spot of the inferior glenoid to the anterior (Da) and posterior (Dp) glenoid rim were measured arthroscopically. In patients with instability, we compared the percentage glenoid bone loss calculated using CT versus arthroscopic measurements.

RESULTS

Among patients without instability, the bare spot could not be identified in three of 27 patients. Da (9.5±1.2 mm) was smaller than Dp (10.1±1.5 mm), but it was not significantly different. However, only 55% of glenoids showed less than 1 mm of difference between Da and Dp, and 18% showed more than 2 mm difference in length. The bare spot could not be identified in five of 40 patients with instability. Pearson's correlation coefficient showed significant (P<0.001) and strong (R (2)=0.63) correlation in percentage glenoid bone loss between the 3D-CT and arthroscopy method measurements. However, in ten shoulders (29%), the difference in percentage glenoid bone loss between 3D-CT and arthroscopic measurements was greater than 5%.

CONCLUSION

The bare spot was not consistently located at the center of the inferior glenoid, and the arthroscopic measurement of glenoid bone loss using the bare spot as a landmark was inaccurate in some patients with anterior glenohumeral instability.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Shoulder Structure and Function Following the Modified Latarjet Procedure: A Clinical and Radiological Review

BACKGROUND

To evaluate the clinical and radiological outcomes of the modified Latarjet procedure for traumatic, antero-inferior glenohumeral joint instability.

METHODS

Case series were used with a mean follow-up of 21.3 months for clinical and radiological review and 47.2 months for recurrent instability. Shoulder function was evaluated by clinical examination and validated shoulder scales: Western Ontario Shoulder Stability Index (WOSI), Melbourne Instability Shoulder Score (MISS) and l'Insalata Shoulder Questionnaire. Shoulder structure was evaluated by computed tomography.

RESULTS

Thirty-two cases were enrolled (mean age 27.0 years). One patient reported a redislocation during the follow-up period. Clinical examination revealed that the median external rotation (at 0° and 90° abduction) was reduced on the operative side by 7.5° (p < 0.01) and 10° (p < 0.001), respectively. Subjective shoulder function was good. Mean (SD) scores on the WOSI, MISS and l'Insalata scales were 78.0 (19.7), 75.8 (11.5) and 89.3 (9.9), respectively. No loss of subscapularis strength was identified (p > 0.05). Radiological evaluation revealed a mean (SD) pre-operative glenoid surface area loss of 169.5 (48.5) mm(2) reconstituted surgically by a bone block of 225.4 (73.8) mm(2). Subscapularis muscle bulk was reduced on the operative side, above the level of the muscle split (p < 0.05).

CONCLUSIONS

The Latarjet procedure reliably restores lost glenoid surface area, shoulder stability, strength and function. A small loss of external rotation is expected and related to altered subscapularis anatomy.

CT-based quantitative assessment of the surface size and en-face position of the coracoid block post-Latarjet procedure

BACKGROUND

The success of shoulder stabilization with the Latarjet procedure might depend on the size of the bone graft and the positioning of the coracoid at the glenoid. The aim of this study was to quantitatively assess the surface of the coracoid bone graft and to assess its positioning in the en-face view.

METHOD

A series of 21 patients (17 men, 4 women, 26.1 ± 6.8 years-9 right, 12 left shoulders) were prospectively included and followed up with CT scans between December 2010 and April 2012 at an average of 2.4 ± 0.7 months postoperatively. The retrospective analysis of the CT scans was performed with Osirix™ software. The coracoid surface was measured (cm(2)) in the sagittal plane. The positioning in relation to the center of the circumscribed circle of the glenoid was determined in the en-face clock face view of the glenoid.

RESULTS

The grafts had a mean surface of 1.61 ± 0.51 cm(2) (mean ± standard deviation). The coracoid grafts were located between 01:05 hours (32.5°) and 05:33 hours (166.6°). Mean positioning was 02:00 hours (59.8° ± 16.1°) to 04:26 hours (133.0° ± 16.9°). The extent of the grafts was 73.2° ± 14.3°.

DISCUSSION

The positioning of the coracoid graft on the clock face of the glenoid is situated in the decisive zone of 02:30-04:20 hours. The mean surface of the graft is smaller than expected from anatomical studies, but restores in defect situations bone stock in the potential defect areas at the anterior glenoid rim.

LEVEL OF EVIDENCE

Level IV, prospective case series, treatment study.

Bone loss in anterior instability

Bone loss is commonly observed in shoulders with anterior instability. The Latarjet procedure is commonly performed when a glenoid bony defect exists that is greater than 25 % of the glenoid width or when the risk of recurrent instability is higher (i.e., collision-sport athletes). Hill-Sachs lesions need to be assessed as well. For the purpose of assessing the bipolar lesions, the glenoid track concept is useful. A Hill-Sachs lesion that is located more medially than the medial margin of the glenoid track is defined as an engaging Hill-Sachs lesion. A potential treatment for such a condition is remplissage, but this procedure also decreases range of motion. Thus, its application in overhead athletes needs to be carefully considered.

Do the traditional and modified latarjet techniques produce equivalent reconstruction stability and strength?

BACKGROUND

The Latarjet procedure has been described as a reconstructive option for instability associated with substantial glenoid bone defects. A modification, termed the Congruent-Arc, is thought to improve glenoid reconstruction through better articular congruency and greater bone reconstitution. The strengths of these techniques, however, have not been reported. Purpose/

HYPOTHESIS

To compare the fixation stability, strength, glenoid vault load transfer, and joint contact between the Classic and Congruent-Arc techniques. The authors hypothesized that the Classic Latarjet would exhibit inferior joint contact characteristics while having greater stability and strength and more normal glenoid vault strain.

STUDY DESIGN

Controlled laboratory study.

METHODS

Sixteen shoulder specimens (8 pairs) were tested by loading the glenohumeral joint with the glenoid intact, following creation of a 25% anterior bone defect, and after random assignment to the Classic or Congruent-Arc Latarjet techniques. Specimens were mounted to a testing apparatus that allowed concentric, centralized loading and loading 30° anterior on the glenoid rim. Cyclic loading (100 cycles at 1 Hz) was applied with a staircase protocol (50, 100, 150, and 200 N). Graft interface displacement and glenoid load transfer, quantified in terms of strain, were recorded during loading. Contact was quantified during 50-N loading using a thin pressure sensor. After cyclic loading, specimens were loaded to failure, defined as 5 mm of graft interface displacement.

RESULTS

The 30° loading ≥100 N resulted in significantly greater graft displacement (P < .004) in the Congruent-Arc group as compared with the Classic (mean displacement range, 0.9-2.6 vs 0.1-0.5 mm, respectively). Failure testing yielded a significantly (P = .010) greater ultimate strength for the Classic (557 N) as compared with the Congruent-Arc (392 N). Load-transfer measurements demonstrated that neither technique's glenoid vault strain values significantly differed from intact (P ≥ .076). Both techniques resulted in contact areas significantly less than intact (P < .035); however, the Congruent-Arc trended toward better contact characteristics (P = .074).

CONCLUSION

The Congruent-Arc results in significantly poorer fixation stability as compared with the Classic technique but did more closely reproduce intact joint contact, which may yield more favorable long-term outcomes.

CLINICAL RELEVANCE

Care must be taken in balancing the consideration of initial fixation stability and joint contact for the Congruent-Arc and Classic Latarjet, as these factors have opposing implications for each of the 2 reconstructions' outcomes.

An anatomic, computed tomographic assessment of the coracoid process with special reference to the congruent-arc latarjet procedure

PURPOSE

The purpose of this study was to determine the dimensions of the coracoid and to compare the radius of curvature (ROC) of the intact glenoid to the ROC of the coracoid undersurface, as oriented in the congruent-arc Latarjet procedure. The ROC of the coracoid undersurface was also compared with various glenoid bone loss scenarios.

METHODS

Thirty-four computed tomography-based 3-dimensional models of the shoulder were examined by use of commercially available software. The mean dimensions of the coracoid were determined, and the ROC was calculated for the coracoid undersurface, the intact glenoid, and 20%, 35%, and 50% anterior glenoid bone loss scenarios. Intra-rater and inter-rater statistics were calculated.

RESULTS

The mean length, width, and thickness of the coracoid were 16.8 mm (SD, 2.5 mm), 15.0 mm (SD, 2.2 mm), and 10.5 mm (SD, 1.7 mm), respectively. The mean ROC values were 13.6 mm (SD, 3.4 mm) for the coracoid, 13.8 mm (SD, 2.1 mm) for the intact glenoid, 27.6 mm (SD, 5.3 mm) for 20% anterior glenoid bone loss, 30.5 mm (SD, 5.2 mm) for 35% bone loss, and 33.3 mm (SD, 5.2 mm) for 50% bone loss. The coracoid ROC was not significantly different from the intact glenoid (P = .75); however, it was significantly less (P < .01) when compared with all glenoid bone loss scenarios. Intra-rater reliability and inter-rater reliability were good or excellent. A coracoid oriented in the congruent-arc manner can reconstitute a significantly greater glenoid bone defect than a coracoid oriented in the classic manner (P < .001).

CONCLUSIONS

This image-based anatomic study found that the ROC of the coracoid undersurface matches the ROC of the intact anterior glenoid articular margin. In conditions with anterior glenoid bony deficiency, the radii of curvature differ significantly at the graft-native glenoid interface; however, the coracoid graft placed in the congruent-arc manner reconstitutes the ROC of the missing anterior glenoid rim. In addition, orienting the coracoid in the congruent-arc manner can reconstitute a greater glenoid bone defect than a coracoid placed in the original manner as described by Latarjet.

CLINICAL RELEVANCE

The congruent-arc Latarjet procedure, a modification of the original procedure, is truly congruent in relation to the intact anterior glenoid rim. In addition, the congruent-arc modification can reconstitute a greater glenoid bone defect when compared with the original Latarjet procedure.