Arthroscopic reduction and hollow screw internal fixation for Eyres Type IIIA scapular coracoid fracture: a case report.

BACKGROUND: A coracoid process fracture combined with an acromioclavicular (AC) joint dislocation is an uncommon injury that typically causes significant pain and limits shoulder movement. Open reduction and internal fixation have been the traditional treatment approach. However, arthroscopic techniques are emerging as a promising alternative for managing these injuries. CASE REPRESENTATION: A 35-year-old woman presented with right shoulder pain following an accidental fall. Imaging studies revealed a coracoid process fracture along with an AC joint dislocation. The fracture was classified as an Eyres Type IIIA, which warranted surgical intervention. Our team performed arthroscopic coracoid fracture reduction and internal fixation surgery, as well as AC joint dislocation repair using Kirschner wires. Six months after surgery, the patient demonstrated a satisfactory functional outcome with complete bone healing. CONCLUSION: This case report highlights the potential of arthroscopic reduction and fixation as a novel treatment option for fractures of the coracoid base.

The Impact of Coracoid Tip Orientation on Subscapularis Tear Incidence: an MRI-Based Study.

PURPOSE OF THE STUDY: This study investigated the relationship between the position of the tip of the coracoid process (CP) relative to the glenoid with subscapularis (Ssc) tears. We hypothesized that the coracoid tip is more inferior, lateral and posterior in patients with Ssc tear. MATERIAL AND METHODS: This research enrolled 34 isolated Ssc tears and 44 controls. We introduced the axial central glenoid-coracoid angle (acGCA) and sagittal central glenoid-coracoid angle (scGCA) to evaluate the position of the tip of the CP relative to the glenoid center on MRI images. In both groups, acGCA, scGCA on MRI and critical shoulder angle (CSA), glenoid inclination (GI) on true anterior-posterior shoulder radiography were evaluated. RESULTS: When both groups were compared in terms of acGCA, the acGCA values of the Ssc tear group were significantly higher than the control group (p<0.001). The best cut-off value of acGCA for Ssc tears was 28.3°. acGCA values higher than 28.3° showed 93.3% sensitivity and 93.1% specificity for Ssc tears (likelihood ratio:13.53, AUC: 0.979, 95% CI of AUC: 0.950- 0.999). In terms of acGCA, the power analysis between Ssc tears group and control group was 99.9% between Ssc tears and the control group (effect size d=2.63). When both groups were compared in terms of scGCA, the scGCA values of the Ssc tear group were significantly higher than the control group (p<0.001). The best cut-off value of scGCA for Ssc tears was 41.4°. Scores of scGCA greater than 41.8° showed 80% sensitivity and 89.7% specificity for Ssc tears (likelihood ratio: 7.73, AUC: 0.899 95% CI of AUC: 0.837-0.958). In terms of scGCA, the power analysis between Ssc tear and control group was 99.8% (effect size d=1.23). When both groups were compared in terms of CSA and GI; CSA and GI values in the Ssc tear group were significantly higher (p<0.001 and p<0.012, respectively). CONCLUSIONS: AcGCA values higher than 28.3° indicate that the coracoid tip is located more laterally and posteriorly; scGCA values higher than 41.8° indicate that the coracoid tip is located more inferiorly and these two new indexes are showing that more laterally, posteriorly and inferiorly coracoid tip is related to subscapularis tears. KEY WORDS: coracoid process, subscapularis tear, coracoid morphology, scapula morphology.

Long-term stability of coracoclavicular suture fixation for acute acromioclavicular joint separation.

PURPOSE: The optimal (SBJI) surgical treatment for acute acromioclavicular (AC) joint disruption remains controversial. What is being presented is the long-term functional outcomes of a double cross-looped coracoclavicular (CC) suture technique with the intention of restoring both anteroposterior and superior displacement of the clavicle. METHODS: Between 2007 and 2016, 81 patients underwent surgical reconstruction for acute acromioclavicular joint (AC) disruption in two orthopaedic centers. Two patients died for reasons unrelated to the treatment, and seven missed the final follow-up appointment, leaving 72 patients (67 males; 5 females; age 37 ± 12.4; range 15-64 years) for clinical and radiological assessments. All cases were classified according to the Rockwood classification as type III (n = 34), IV (n = 14) or V (n = 24). The dislocation was repaired with double cross-looped CC fixation using four Ethibond sutures passing underneath the coracoid and through a 4.5 mm drill hole in the clavicle in opposing directions to control both anteroposterior and vertical displacement. Radiological investigation preoperatively and at the last follow-up included anteroposterior and/or Zanca views, axillary or Alexander views, and comparative stress radiography of both AC joints. Patients were evaluated clinically with the Constant-Murley score (CMS) and Acromio Clavicular Joint Instability Score (ACJIS). Loss of reduction, subluxation, CC ligament ossification, post-traumatic arthritis, and peri-implant fractures were also recorded. RESULTS: Seventy-two patients were available for the last clinical and radiological evaluations. At a median follow-up period of 6.3 ± 2.1 years (range 3-12 years), the CMS and ACJIS were 92.1 ± 7.2 (range 60-100 points) and 90.4 ± 8.6 (range 45-100 points), respectively. Complications included 9 (12.5%) patients with slight loss of reduction, 2 (1.7%) with dislocation recurrence, 1 (1.3%) with superficial infection, 1 (1.3%) with a fracture of the lateral end of the clavicle, and 2 (1.7%) with persistent tenderness in the AC joint. The incidence of periarticular ossification was 22.4% and did not affect the final outcome. CONCLUSIONS: This technique represents an effective and low-cost treatment for acute AC joint separations. LEVEL OF EVIDENCE: IV.

Treatment of coracoid process fractures: a systematic review.

INTRODUCTION: The coracoid process is a small hook-shaped feature on the scapula and a key structure of the superior shoulder suspensory complex (SSSC). Fractures of the coracoid are rare. Therefore, no consensus exists regarding treatment of coracoid process fractures. Systematically review indications, outcomes and complications of traumatic coracoid process fractures in adults, and to provide a treatment algorithm. MATERIALS AND METHODS: A systematic review was performed to identify all relevant studies on the treatment of coracoid process fractures. The methodological quality of the studies was scored using the Methodological Index for Non-Randomized Studies (MINORS). RESULTS: Eight case series, with a total of 110 coracoid process fractures, were included. All studies were of moderate methodological quality. Of the fractures, 78% were Ogawa type I fractures, 13% Ogawa type II and 9% were unclassified. Conservative treatment showed good results in most Ogawa type II fractures and type I fractures without associated disruptions of the SSSC. Most Ogawa type I fractures with associated disruptions of the SSSC received surgical treatment showing good results. CONCLUSION: Based on moderate quality studies, surgical treatment may be considered in Ogawa type I fractures with multiple disruptions of the SSSC. A conservative treatment seems sufficient in other fracture types.

Coracoid stress fracture in an elite fast bowler: description of a technique for CT-guided percutaneous screw fixation of coracoid fractures.

Coracoid stress fractures are a rare sports injury but present a management challenge, with the focus on optimising return-to-play, whilst minimising complications. Potential contributing mechanisms for the injury are briefly discussed and a novel approach to accurate fracture fixation under CT guidance is described. The ability of radiologists to orient themselves in 3D with a volume dataset on a workstation provides an image-guided option for percutaneous fixation that minimises risk of complications.

Clavicle and coracoid process periprosthetic fractures as late post-operative complications in arthroscopically assisted acromioclavicular joint stabilization.

PURPOSE: Arthroscopic-assisted stabilization surgery for acute acromioclavicular joint (ACJ) disruption shows excellent and reliable clinical outcomes. However, characteristic complications such as fracture of the clavicle and coracoid have been reported to occur during the early post-operative period. The main goal of this study was to highlight the occurrence of fractures as a late post-operative complication. The secondary goals were to describe possible fracture morphologies and treatment outcomes. METHOD: Patient records from a single surgery centre were searched for all patients presenting with late fracture complication following arthroscopically assisted acromioclavicular stabilization. Medical reports including the operative notes and pre- and post-operative X-rays were reviewed. A telephone interview was conducted with each patient to access the American Shoulder and Elbow Surgeons shoulder score. RESULTS: A total of four patients presented with late fracture complication following arthroscopic-assisted ACJ stabilization surgery. All patients were males and presented following trauma at a median duration of 19.5 months after the index surgery. Fracture morphology differed between patients; the treatment was conservative in three patients, while one patient underwent osteosynthesis. CONCLUSION: Traumatic peri-implant fractures can occur, even 2 years after arthroscopically assisted ACJ reconstruction. This needs to be considered when planning for surgical intervention in acute ACJ disruption, especially in a high-risk population. LEVEL OF EVIDENCE: Therapeutic study, Level IV.

Double-row fixation of the transferred coracoid process: a rescue technique for intraoperative coracoid fracture during the Latarjet procedure.

BACKGROUND: The Latarjet procedure is the preferred method to treat recurrent anterior shoulder instability with glenoid deficiency. An iatrogenic fracture of the transferred coracoid process is one possible intraoperative complication. METHODS: We propose a rescue technique using double-row suture bridge fixation. Double-loaded 4.5-mm suture anchors were placed medially in the scapular neck. These sutures were then brought over the top of the coracoid fragment, placed around the bony fragment, and fixated to the glenoid face with knotless suture anchors. RESULTS: Radiologic evidence of bone graft healing was observed in the desired position. CONCLUSIONS: We present a salvage procedure that will assist surgeons if an intraoperative fracture of the coracoid bone graft occurs during fixation when performing the Latarjet procedure.

Coracoid process fractures: anatomy, injury patterns, multimodality imaging, and approach to management.

The coracoid process of the scapula is in close proximity to major neurovascular structures, including the brachial plexus and the axillary artery and vein. In addition, it serves as a major site of attachment for multiple tendons and ligaments about the shoulder. Isolated coracoid fractures are rare; however, they can be easily overlooked on routine shoulder radiographs. Importantly, when these fractures go undiagnosed, they are at high risk for nonunion. In this paper, we will review the relevant anatomy of the coracoid process, classification schemes for coracoid fractures, mechanisms of injury how these fractures typically present, multimodality imaging findings, and associated injuries. Finally, we will briefly discuss the clinical management of these fractures.

[Ipsilateral Fractures of the Coracoid and Acromion Process of the Scapula Combined with the Distal Clavicle End Fracture, Treatment Options]. / Ipsilaterální zlomenina processus coracoideus a akromionu lopatky v kombinaci se zlomeninou laterální cásti klavikuly, terapeutická moznost resení.

Superior Shoulder Suspensory Complex (SSSC) is a bone and soft-tissue ring securing the connection of the upper extremity to the axial skeleton via the clavicle and sternoclavicular joint. An isolated injury to one component of SSSC is usually stable. An injury to 2 of its components is a potential source of shoulder girdle instability and requires surgical stabilisation. An injury affecting 3 and more components is extremely rare and surgical stabilisation should be indicated. Our study presents the case of a 50-year-old man who fell off the bicycle and sustained a direct blow to his left shoulder resulting in an ipsilateral fracture of the coracoid and acromion process combined with the fracture of the distal end of the clavicle. Following a standard clinical examination and a subsequent X-ray and a CT scan with three-dimensional shoulder reconstruction, an open reduction and stabilisation of all the injured SSSC components was performed. Later, early and gradual rehabilitation of the shoulder girdle was commenced. At 48 weeks after the surgery, almost full range of motion of the shoulder joint was achieved and the muscle strength of the operated upper extremity was comparable to that of the healthy one. Key words:Superior Shoulder Suspensory Complex, fracture, acromion, coracoid process, clavicle.

Anatomic Tunnel Placement Is Not Feasible by Transclavicular-Transcoracoid Drilling Technique for Coracoclavicular Reconstruction: A Cadaveric Study.

PURPOSE: To evaluate the feasibility of anatomic tunnel placement by a transclavicular-transcoracoid drilling technique and with reference to the coracoclavicular ligaments' insertional anatomy and their orientations. METHODS: We used 12 fresh-frozen human cadaveric shoulders (6 matched pairs; mean age, 70 years; age range, 51-82 years) to simulate intraoperative tunnel placement with the transclavicular-transcoracoid drilling technique. After both the conoid and trapezoid ligaments were identified, two 2.5-mm guide pins were inserted from the clavicle to the coracoid, passing the centers of the clavicular and coracoid insertions of the conoid and the trapezoid ligaments, in a collinear fashion to the orientation of both ligaments. The entry point of the drill at the clavicle and the exit point at the coracoid undersurface, as well as the tunnel orientations, were measured. Complications due to the procedure, including a breach of the bone cortex of the clavicle and/or coracoid process, were recorded. RESULTS: The transclavicular-transcoracoid drilling technique for anatomic conoid ligament tunnel placement resulted in a medial cortical breach at the coracoid process in 6 of 12 shoulders. In the remaining 6 shoulders without a breach, the distance of the exit point from the medial cortex of the inferior coracoid process was only 3.6 ± 4.3 mm. For anatomic trapezoid ligament tunnel placement, no medial cortex breaching at the coracoid process occurred. However, the distance of the exit point was 3.1 ± 4.2 mm, indicating an eccentric location to the medial cortex of the coracoid process, similar to the conoid ligament. CONCLUSIONS: This cadaveric study showed that anatomic tunnel placement by the transclavicular-transcoracoid drilling technique would not be feasible without breaching or almost breaching the medial cortex of the coracoid process. CLINICAL RELEVANCE: The transclavicular-transcoracoid drilling technique for CC ligament reconstruction may not reproduce the anatomy of the CC ligaments but may place the coracoid process at high risk of fracture during tunnel placement.

Concomitant coracoplasty during arthroscopic subscapularis repair does not yield better clinical outcomes and structural integrity.

PURPOSE: Few studies have examined whether concomitant coracoplasty is necessary to improve clinical and radiological outcomes after arthroscopic subscapularis repair. The purpose of this study was to compare clinical outcomes and structural integrity after arthroscopic repair of isolated subscapularis full-thickness tear, either with or without concomitant coracoplasty. METHODS: This study included 62 patients who underwent arthroscopic subscapularis repair either with coracoplasty (Group A, 35 patients) or without coracoplasty (Group B, 27 patients). Preoperative and postoperative visual analog scale pain scores, subjective shoulder values, University of California at Los Angeles shoulder scores, American Shoulder and Elbow Surgeon scores, subscapularis strength, and shoulder active range of motion (ROM) were assessed. Postoperative magnetic resonance arthrography (MRA) or computed tomographic arthrography (CTA) was performed 6 months postoperatively for structural integrity assessment. RESULTS: At 2-year follow-up, all functional scores and ROM improved significantly in both groups compared with preoperative values (p < 0.001). However, none of these values differed significantly between groups. On follow-up MRA or CTA images, although postoperative coracohumeral distance was significantly greater in Group A (8.4 mm ± 2.3 mm versus 7.0 mm ± 2.0 mm) (p = 0.018), the re-tear rates were not significantly different between groups (5/35 (14%) in Group A and 4/27 (15%) in Group B). CONCLUSIONS: For isolated subscapularis full-thickness tears, concomitant coracoplasty with arthroscopic repair did not produce better clinical outcomes or structural integrity than repair without coracoplasty. This suggests that concomitant coracoplasty may not be imperative during arthroscopic repair of isolated subscapularis full-thickness tears. LEVEL OF EVIDENCE: III.

An unusual mechanism of coracoid fracture in a beginner golfer.

Golfers may injure themselves as a result of repetitive asymmetrical loads exerted on the body by poor swing mechanics. If the repetitive sub-maximal loading is not removed, this repetitive loading will exceed the adaptive capacity of bone, eventually resulting in a stress fracture. Stress fracture of the scapula due to golfing is extremely rare. Only two cases of acromion fracture have been reported. A rare case of nontraumatic coracoid fracture in a 50-year-old female beginner golfer is reported here. The mechanism of injury is also discussed. Level of evidence Level IV.

[Simultaneous fracture of the acromion and coracoid process : Rare variant of double disruption of the superior shoulder suspensory complex]. / Gleichzeitige Frakturen von Acromion und Korakoid : Seltene Variante der doppelten Unterbrechung des "superior shoulder suspensory complex".

INTRODUCTION: Simultaneous fracture of the acromion and coracoid process represents a double disruption of the superior shoulder suspensory complex (SSSC). To date, the two largest reported series have comprised five and eight cases. The aim of this study was to investigate the functional outcome in patients who sustained this rare injury and to provide a review of the relevant literature. MATERIAL AND METHODS: In this retrospective study, patients who were surgically treated between 2009 and 2014 were identified from medical records and the patients were asked to attend a follow-up examination. Functional results, measured as the Constant score and Disabilities of the Arm, Shoulder and Hand (DASH) score, were the main outcomes of the study. RESULTS: A total of six patients underwent surgery for this type of double disruption of the SSSC. All but one patient suffered a high-impact trauma with other associated injuries. The coracoid fracture was classified as type I according to Ogawa in all cases, and the acromion fracture was type III according to Kuhn in 5 out of 6 cases. At least one of the fracture sites was stabilized. Of the patients one showed a concurrent lateral clavicle fracture, representing a third disruption of the SSSC, and another had a fracture of the medial third of the clavicle, representing a strut fracture. In these cases, two fracture sites were operated on. At an average follow-up period of 47 months all but one fracture had healed. In one patient, asymptomatic non-union of the acromion was found. The average DASH score was 22 points and the average Constant score was 74 points. CONCLUSION: This rare injury pattern is usually caused by high-impact trauma, and concomitant injuries frequently occur. Nevertheless, surgical stabilization of at least one of the fracture sites showed satisfactory functional results.

Outcomes of Conservatively Managed Coracoid Fractures in Wild Birds in the United Kingdom.

Coracoid fractures are a frequent presentation in wild birds, commonly caused by collisions with motor vehicles, windows, or other obstacles such as pylons. Despite this, there are few reports of outcomes, and those published consist of small numbers of birds with conflicting results when comparing conservative management with surgical intervention. To determine outcome success of conservative management in a larger population of wild birds, records of 232 adult wild birds in the United Kingdom (UK) with closed unilateral coracoid fractures confirmed on radiography and surviving more than 48 hours after admission were retrospectively analyzed. Conservative management had a high success rate, with 75% (n = 174/232; 95% confidence limits [CL]: 69%, 80%) of all birds successfully released back to the wild. The proportion of raptors successfully returned to the wild was even higher at 97% (n = 34/35; 95% CL: 85%, 99%). A significant difference of 26% (95% CL: 18%, 34%, Fisher exact test, P < .001) was demonstrated when comparing the outcome success of raptors (97%, n = 34/35) to nonraptors (71%, n = 140/198). The median time in captive care until released back to the wild was 30 days (95% CL: 27, 33). Conservative management of coracoid fractures in wild birds in the UK, and in particular in raptors, appears to result in good outcomes. The approach is low cost and noninvasive, in contrast to surgery, and is recommended as the first-line approach of choice in these cases.

The "triple dislocation fracture": anterior shoulder dislocation with concomitant fracture of the glenoid rim, greater tuberosity and coracoid process-a series of six cases.

BACKGROUND: A combined fracture of the glenoid rim, greater tuberosity, and coracoid process after anterior shoulder dislocation is a rare event. Only 1 patient has been reported in the literature. METHODS: All patients with a first-time traumatic anterior shoulder dislocation in a level A trauma center were retrospectively reviewed. Among the 2068 patients treated between 1998 and 2013, we identified 6 patients (0.3%; 1 female, 5 male) with "triple dislocation fracture" (anterior shoulder dislocation with concomitant fracture of the glenoid rim, greater tuberosity, and coracoid process). All patients underwent surgery and had computed tomography scans before surgery and the first postoperative day. Mean follow-up time was 59 months. Clinical and radiographic evaluation, Constant-Murley Score, Simple Shoulder Test, and Subjective Shoulder Value were performed at the final follow-up. RESULTS: Surgery was determined individually according to the radiologic findings, patient's age, and personal demands. Glenoid reconstruction was performed in all 6 patients, greater tuberosity refixation in 4 patients, and coracoid process refixation in 3. Two patients needed revision surgery due to loss of reduction. At the final follow-up, mean abduction was 133°, mean anterior flexion was 138°; the mean Constant-Murley Score was 72 points; the mean Simple Shoulder Test was 9 points; and the mean Subjective Shoulder Value was 72%. No recurrent instability occurred. CONCLUSIONS: A "triple dislocation fracture," especially coracoid process fractures, can easily be overlooked in radiographs. Computed tomography scans are strongly recommended in patients with a first-time traumatic shoulder dislocation. Because recurrent joint instability and secondary arthropathy are serious complications after anterior shoulder dislocation, surgery should be considered and provides satisfying to excellent results.

Coracoid bypass procedure: surgical technique for coracoclavicular reconstruction with coracoid insufficiency.

BACKGROUND: Failed acromioclavicular (AC) joint reconstruction secondary to a coracoid fracture or insufficiency of the coracoid is an uncommon but challenging clinical situation. We describe a surgical technique of revision coracoclavicular (CC) reconstruction, the coracoid bypass procedure, and report short-term results with this technique in 3 patients. METHODS: In the coracoid bypass procedure, reconstruction of the CC ligaments is performed by passing a tendon graft through a surgically created bone tunnel in the scapular body (inferior to the base of the coracoid) and then fixing the graft around the clavicle or through bone tunnels in the clavicle. Three patients treated with this technique were retrospectively reviewed. RESULTS: AC joint reconstruction performed for a traumatic AC joint separation failed in the 3 patients reported in this series. The previous procedures were an anatomic CC reconstruction in 2 patients and a modified Weaver-Dunn procedure in 1 patient. The coracoid fractures were detected postoperatively, and the mean interval from the index surgery to the coracoid bypass procedure was 8 months. The patients were a mean age of 44 years, and average follow-up was 21 months. At the last follow-up, all 3 patients were pain free, with full range of shoulder motion, preserved CC distance, and a stable AC joint. CONCLUSION: The coracoid bypass procedure is a treatment option for CC joint reconstruction during revision AC joint surgery in the setting of a coracoid fracture or coracoid insufficiency.

Coracoid Process: The Lighthouse of the Shoulder.

The coracoid process is a hook-shaped bone structure projecting anterolaterally from the superior aspect of the scapular neck. Surgeons often refer to the coracoid process as the "lighthouse of the shoulder" given its proximity to major neurovascular structures such as the brachial plexus and the axillary artery and vein, its role in guiding surgical approaches, and its utility as a landmark for other important structures in the shoulder. The coracoid also serves as a critical anchor for many tendinous and ligamentous attachments. These include the tendons of the pectoralis minor, coracobrachialis, and short head of the biceps brachii muscles, and the coracoclavicular, coracohumeral, coracoacromial, and transverse scapular ligaments. Consequently, the coracoid and its associated structures are linked to numerous shoulder pathologic conditions. This article will detail the anatomy of the coracoid and its associated structures and review the clinical and radiologic findings of corresponding pathologic conditions in this region with original illustrations and multimodality imaging examples. Highlighted in this article are the coracoclavicular joint, the classification and management of coracoid fractures, subcoracoid impingement, the coracoacromial arch and subacromial impingement, the coracohumeral ligament and the biceps pulley, the coracoclavicular ligament and its surgical reconstruction, adhesive capsulitis, the suprascapular notch and suprascapular notch impingement, subcoracoid bursitis, coracoid transfer procedures, and coracoid tumors. A brief summary of the pathophysiology, potential causes, and management options for each of the pathologic entities will also be discussed. ©RSNA, 2016.

Effect of Coracoid Drilling for Acromioclavicular Joint Reconstruction Techniques on Coracoid Fracture Risk: A Biomechanical Study.

PURPOSE: To biomechanically compare the stability of the coracoid process after an anatomic double-tunnel technique using two 4-mm drill holes or a single-tunnel technique using one 4-mm or one 2.4-mm drill hole. METHODS: For biomechanical testing, 18 fresh-frozen cadaveric scapulae were used and randomly assigned to one of the following groups: two 4-mm drill holes (group 1), one 4-mm drill hole (group 2), or one 2.4-mm drill hole (group 3). After standardized coracoid drilling, load was applied to the conjoined tendons at a rate of 120 mm/min and ultimate failure load, along with the failure mode, was recorded. RESULTS: There was no significant difference between groups regarding load to failure. Mean load to failure in group 1 was 392 N; group 2, 459 N; and group 3, 506 N. The corresponding P values were .55, .74, and .20 for group 1 versus group 2, group 2 versus group 3, and group 1 versus group 3, respectively. However, the failure mode for the group with one 4-mm drill hole and the group with two 4-mm drill holes was coracoid fracture, whereas the group with one 2.4-mm drill hole showed 5 tears of the conjoined tendons and only 1 coracoid fracture (P = .015). CONCLUSIONS: Although there was no significant difference regarding load-to-failure testing between groups, the failure mechanism analysis showed that one 2.4-mm drill hole led to less destabilization of the coracoid than one or two 4-mm drill holes. CLINICAL RELEVANCE: Techniques with small, 2.4-mm drill holes might decrease the risk of severe iatrogenic fracture complications.

A guideline for screw fixation of coracoid process base fracture by 3D simulation.

BACKGROUND: Fractures of the base of the coracoid process are relatively rare, but an increasing number of studies have reported using screws to fix coracoid process base fractures. This study was performed to simulate the surgical procedure and obtain the ideal diameter, length, insertion point and angle of the screw from a 3-D axial perspective in Chinese patients. METHODS: We randomly collected right scapula computed tomography (CT) scans from 100 adults. DICOM-formatted CT scan images were imported into Mimics software. A 3D digital model of the right scapula was established. Two virtual cylinders representing two screws were placed from the top of the coracoid process to the neck of the scapula and across the base of the coracoid process to fix the base of the coracoid process. The largest secure diameters and lengths of the virtual screws were measured. The positions of the insertion points and the directions of the screws were also examined. RESULTS: The screw insertion safe zone can exhibit an irregular fusiform shape according to the reconstructed scapula model. The mean maximum diameters of the medial and lateral screws were 7.08 ± 1.19 mm and 7.34 ± 1.11 mm, respectively. The mean maximum lengths of the medial and lateral screws were 43.11 ± 6.31 mm and 48.16 ± 6.94 mm, respectively. A screw insertion corridor with a diameter of at least 4.5 mm was found in all patients. We found sex-dependent differences in the mean maximum diameters and maximum lengths of the two screws. The positions of the two insertion points were statistically different across sexes. CONCLUSIONS: The study provides a valuable guideline for determining the largest secure corridor for two screws in fixing a fracture at the base of the coracoid process. For ideal screw placement, we suggest individualised preoperative 3D reconstruction simulations. Further biomechanical studies are needed to verify the function of the screws.