Fractures of the scapula rarely occur and account for approximately 0.4–1% of all fractures. About 10% of these fractures include the glenoid, and the same amount is substantially displaced. Within the glenoid fractures, 75–85% are anterior avulsion or rim fractures [1]. A CT analysis of 218 patients showed 21% glenoid rim fractures in patients with single or recurrent dislocations, of which one-half had a detached fragment while the other half had an attached one [2]. Such fractures can result in persisting glenohumeral instability. The average age of the patients is approximately 35 years and seen four times more in men than in women. Two peaks can be found within the age distribution – the first is seen between the age of 20–30 years, mostly because of high energy trauma. The second peak can be found at the age of around 50–60 years due to dislocating trauma [1].

Fractures of the glenoid basically involve two problems. First the physiologic pressure distribution and loading of the glenoid is significantly altered, if the contact area is decreased due to glenoid bone loss. Greis et al. [3] in 2002 showed that a bone loss of 30% results in a decreased contact area of approximately 40% and an increase in pressure of nearly 100% which might be involve in the pathogenesis of osteoarthritis after instability. Second, studies have demonstrated the increased risk of recurrent instability if the bone loss exceeds 20% of the glenoid surface [4, 5].

The clinical workup should include a radiological imaging of at least a three-plane X-ray. A true AP, Y-view, and axial (alternative: Velpeau view) are needed to detect and evaluate the fracture. For further assessment, a CT scan with 3D reconstruction (with subtraction of humerus) is the current gold standard. With this, the glenoid surface can exactly be measured and determined. Various techniques could be used, to quantify the glenoid size, fragment size, and bone loss as a percentage area using the inferior perfect circle and the help of a computer software [6–8]. While other techniques use the diameter of the perfect circle to calculate the percentage glenoid bone loss [9, 10], MRI is useful to detect concomitant lesions (e.g., RC tears or LHB lesions) (Fig. 31.1).

Multiple classifications can be used to evaluate fractures of the glenoid. One of the most used is the Ideberg [11] classification that was developed in 1985 from a series of AP and lateral radiographs. It is divided into five groups describing intra-articular glenoid fractures ascending in complexity. Type I are anterior rim fracture differentiating among bony fragments less than 5 mm (Ia) and more than 5 mm (Ib), usually seen in shoulder dislocations. From type II to type V, Ideberg describes higher-grade fractures of the glenoid and the scapula. Nevertheless, prognostic value has not been demonstrated, while therapeutic surgical procedures have been described for each type of fracture. Later on this classification system was modified by Goss et al. [12], adding more subgroups with more details, trying to highlight the mechanism and different patterns that may result looking forward improving the management of these fractures. Moreover, Bigliani [13] in 1998 published a classification more specific for anterior glenoid rim fractures associated with glenohumeral instability, independently of the time frame of the lesion. Type I is a displaced avulsion fracture with attached capsule, type II is a malunited fragment medially displaced to the glenoid rim, and type III is a glenoid rim erosion with bone loss less than 25% (IIIa) or more than 25% (IIIb). Hence, a specific treatment for each kind of lesion is suggested [13]. Recently, in 2009 Scheibel [14] evolves the Bigliani classification, differentiating acute and chronic lesions; isolating lesions between avulsion, solitary, and multifragmented; and adding the types of erosion bone loss used by Sugaya [6].

The optimal treatment of glenoid fractures is dependent on multiple factors and ranges from conservative to surgical and from arthroscopically or open surgery to non-anatomic procedures. The decision is based on multiple variables such as the thorough analysis of the osseous defect size, time from injury, fragment size, and morphology as well as age and demands of the patient.

We suggest a treatment algorithm based primarily on the time since injury (acute < 3 months vs. chronic > 3 months). Porcellini et al. [15] compared the results of 41 acute glenoid fractures to 24 chronic with a mean follow-up of 48 months after suture anchor repair. The Rowe score at final follow-up (acute 59 points vs. chronic 61 points) as well as the percentage of return to sports (78% vs. 40%) was better in the acute group compared to the chronic. Plath et al. [16] also showed advantages for the acutely treated cases, although differences in their study were not significant.

The size of the fragment in correlation to the glenoid size is the second important factor. In addition, the type of fragment (solitary vs. multifragment) has to be considered as well as general factors such as the age and demands of the patient.

Treatment options for acute fractures highly depend on the size of the fragment and age of the patient. Fragments should be classified to be small rim lesions (<5%), small fragments (<15%), or larger fragments (>15%). This has to be seen in correlation to the glenoid size, which should result in a bony surface of at least 80% after adding together the glenoid surface area with the area of the bony fragment, to permit persisting stability of the glenohumeral joint.

If the fragment is small such as a glenoid rim lesion (<5%), without significant glenoid defect, general risk factors are known from shoulder instability and have to be considered. Salomonsson et al. [17] have shown that in these cases, a solitary fragment smaller than 15% is a positive predictive factor in comparison with labral lesions alone. When a fragment is less than 15%, seems not to increase further the instability process compared to a classic Bankart lesion. Therefore, a patient older than 30 years with no concomitant intra-articular lesions (e.g., SLAP, loose body, etc.) might be treated nonsurgically.

When the patient is younger than 30 years and/or has high athletic demands, an arthroscopic labral repair should be performed to regain stability of the joint because of the overall high reluxation risk of these patients. A recent meta-analysis showed that the luxation rate in the age group between 15–20 and 15–30 is almost 50%; on the contrary with more than 40 years, the recurrence percentage is 11% [18]. The highest odds ratio for presenting recurrent instability was in people with less than 40 years, followed by being male and having hyperlaxity [18].

Several techniques have been described to achieve this. The fragment can be arthroscopically repositioned and fixed by a suture anchor repair according to the technique described by Sugaya [19]. For this, a suture anchor is positioned inferior and superior to the repositioned fragment (Fig. 31.2).

An alternative fixation for solitary fragments can be achieved by the bony Bankart bridge technique described by Millett et al. [20]. Therefore, a suture anchor is fixed medially to the fragment and then fixed with the second row at the glenoid. Biomechanical studies have shown that both techniques have positive results. Although the study from Giles et al. [21], comparing single-point suture anchor vs. double-point, have equivalent failure strengths and load transfers but greater initial fracture fragment stability in favor of the suture-bridge technique. Similarly, Spiegl et al. [22] found improved fracture reduction and superior stability at time zero in the double-row technique (Fig. 31.3).

If a bigger solitary fragment of more than 15% is found, fixation should be intended. However, in cases of a centered joint, a step-off less than 2 mm, no concomitant lesions, and patients with lower demands especially with more than 30 years, a conservative treatment might be successful [23–26]. Gerber et al. [27] demonstrated good clinical results for such conservative treatment in patients with a mean age of 53 years (ratio, 32–73) with concentric reduction of the humeral head after a closed reduction. In the literature the conservative treatment has shown good results following these criteria with 100% of the bony healing [27–30]. Nevertheless, all other cases should be treated surgically. The different methods that have been described to treat bony Bankart, all of them have achieved good clinical results [7, 20, 26, 31–34]. Surgeons can choose between suture fixation, bony Bankart bridge, or screw fixation of the fragment. Arthroscopic and open techniques were proven to achieve positive results. Scheibel et al. [32] published similar scores after open procedures with suture anchors in defects less than 25% and with two cannulated screws in defects larger than 25% of the glenoid surface (mean Constant score, 85.5 points vs. 87.2 points). The second study [35] presented good and excellent clinical results after arthroscopic procedure for large solitary and multifragment lesions with suture anchor, with screws, or with a combined technique (mean Constant score, 84.5 points) without complications; however, 6 patients of 21 presented different grades of osteoarthritis.

Surgeons should keep in mind that, if the addition of the fragment with the glenoid results in a surface area greater than 80%, good prognosis regarding stability can be expected. Otherwise, if the surface area is smaller, the risk for symptomatic instability in an active patient increased significantly. The study from Jian et al. [36] showed in a case series report of 50 patients, where three of four cases with redislocation after arthroscopic fixation of the bony fragment had a reconstructed size of the glenoid less than 80%. Therefore, previous analysis of the fragment must be done before the surgery. Furthermore, poorly reduced fractures will not reconstruct the necessary glenoid surface area. In these cases, surgical techniques like bone grafting from the iliac crest or Latarjet procedures should be aimed at preventing further instability.

The indications for chronic cases are symptomatic recurrent instabilities. Again, the surgical technique is primarily based on the size of the fragment as well as the overall bony surface of the glenoid.

If the glenoid size in combination with the fragment exceeds 80%, smaller bony fragments (<5%) may just be involved in an arthroscopic soft tissue repair with anchors, and this has been shown by Sugaya et al. [8, 19]. Fragments with a bigger size (>5%) may be mobilized and fixated with either soft tissue techniques as described by Sugaya et al. [19] or with a bony Bankart bridge technique according to Millett et al. [20] where they did not find worst outcomes in their reports in chronic patients.