Arthroscopic treatment of a multifragmentary glenoid fracture

The online version of this article (https:// doi.org/10.1007/s11678-021-00637-w) contains the video: “Arthroscopic treatment of a multifragmentary glenoid fracture”. You will find the video at the end of the article as “Supplementarymaterial.” Video by courtesy of A. Wafaisade, B. Bouillon, M. Balke und P. Kappel, Department of Trauma and Orthopedic Surgery, University of Witten/Herdecke, Cologne-MerheimMedical Center and Sports Clinic Cologne, Germany; all rights reserved 2021.


Background
Glenoid fractures can lead to persistent glenohumeral instability and posttraumatic osteoarthritis. Generally, surgery is indicated for displaced fractures, in particular those with an articular step greater than 5 mm [1]. Traditionally, these procedures have been performed using extensive arthrotomy, which is associated with higher risks for intraoperative and postoperative complications [2]. Thus, several arthroscopic techniques have been developed to address two-part fractures (anterior rim, posterior rim, or transverse; [3,4]). However, these techniques remain technically challenging, even more so in cases of multifragmentary glenoid fractures, i.e., more than two articular fragments. Accordingly, in the classification of glenoid fractures by Ideberg, any injury pattern involving three or more fragments of the This work was awarded the DVSE Alwin Jäger Video Prize for 2020. articular surface are all summarized as Type "6" [1]. The recent classification of the "Arbeitsgemeinschaft für Osteosynthesefragen" (AO) offers a more detailed subclassification.
Therefore, the aim of this article is to describe a technique for a completely arthroscopic fixation of a three-fragment, y-shaped glenoid fracture (AO14F2.1 or Ideberg "6") in a 25-year-old polytrauma patient (. Fig. 1a) applying modifications of recently described arthroscopic techniques for two-part glenoid fractures [3,4].

Surgical technique
The patient is placed in the beach-chair position. Using a standard posterior portal for visualization, severe displacement of the fragments is appreciated. Both the anterior portal and the anterosuperior portal are established. Hematoma is removed using a shaver. The rotator interval capsule is released, in particular visualizing the inferior and the lateral aspect of the coracoid, with partial release of the coracoacromial ligament. In the present case, since a pulley lesion with a ruptured superior glenohumeral ligament was detected, arthroscopic tenotomy with suprapectoral tenodesis was performed. The arthroscope is then introduced through the anterosuperior portal, remaining there for the rest of the procedure.

Posterior fragment
Several instruments (e.g., elevator, probe) are used via the anterior portal for fracture reduction of the posterior fragment.
Subsequently, a glenoid guide (Smith&Nephew [London, UK]) is introduced into the posterior portal with its anterior hook end, and is advanced anteriorly parallel to the glenoid. The guide is rotated to capture the anterior edge of the glenoid at the 8-o' clock position under the hook, with the guide parallel and flush to the glenoid surface.
Posteriorly, two bullets are then placed over the glenoid guide through an accessory posteromedial skin incision. Each bullet can be advanced until it has firm contact with the posterior fragment, thus supporting fracture reduction. A 1.4mm K-wire is placed through each bullet. Both K-wires are advanced under power, just until reaching the anterior cortex of the scapular neck to avoid penetration of the anterior neurovascular structures. Each K-wire will be 5 mm below the cortical edge of the glenoid surface, parallel to one another and 10 mm apart. At this stage, the bullets and the glenoid guide can be removed posteriorly. In the present case, the upper K-wire exited just above the posterior fragment and was therefore removed again. C-arm fluoroscopy is used to verify the appropriate trajectory. Thus, only the lower K-wire is used to introduce a partially threaded, self-drilling cannulated screw with a 4.

Cranial fragment
With the arthroscope still in the anterosuperior portal, the opening in the rotator interval makes alternating and free visualization of both the glenohumeral joint and the coracoid possible. A serrated reduction clamp ("lobster claw") is placed through the anterior portal to grasp the coracoid firmly. Since the fracture pattern displays a continuous coracoglenoid unit (as in Ideberg Type 3 fractures), the extracorporeal manipulation of the clamp allows for precise reduction of the cranial glenoid fragment.
Further soft tissue was removed from the lateral aspect of the coracoid base to define the starting point of the cranial screw. Therefore, a high anteromedial portal just anterior to the lateral clavicle was established. From this portal, a Kwire was introduced. After visualization with fluoroscopy (. Fig. 2), a cannulated screw was inserted. However, this step had to be repeated from a starting point slightly more medial and posterior because the firstscrewshowed displacement of the posterior fragment. Finally, after removal of both K-wires, stable fixation is confirmed with a probe.
Postoperative three-dimensional computed tomography shows optimal fracture reduction for the posterior fragment and a satisfactory reduction of the cranial fragment with a 1-to 2-mm gap of its posterior aspect (. Fig. 1b). Nine months after surgery, the patient presented with a Subjective Shoulder Value of 90 and a Constant Score of 92.

Discussion
Multifragmentary glenoid fractures are very rare. In the case presented here, surgery was indicated because the three articular fragments showed substantial displacement. However, as traditionally performed, open surgery would have necessitated combined anterior and posterior arthrotomy with a substantial soft tissue trauma [1,2].
To our knowledge, only one case report by Gigante et al. described a similar fracture pattern treated arthroscopically: A distinct reposition technique was not further explained, and fixation was achieved with two percutaneous K-wires, which were removed after 6 weeks [5].
Therefore, we aimed to present a detailed, sufficient, and reproducible allarthroscopic procedure for treatment of multifragmentary, y-shaped glenoid fractures: First, with the arthroscope in the anterosuperior portal, free and alternating visualization of both the glenoid and the coracoid is possible.
Originally, the glenoid guide was designed for implantation of a button-suture construct, but allowed for safe placement of the posterior screw in the present case [4]. Also, the posterior bullets aided in fracture reduction.
Furthermore, the reduction clamp grasping the coracoid through the anterior portal enables easy reduction of the cranial glenoid fragment with extracorporal manipulation [3].
Finally, since the cranial screw was introduced from the lateral aspect of the coracoid base, a Neviaser portal was not necessary, thus minimizing the risk of penetration of the supraspinatus or of suprascapular nerve injury.