Arthroscopic Repair of a Posterior Midcapsular Rupture Causing Posterior Shoulder Instability

Background: Gross posterior instability is rare and when found likely has an injury or deficiency to the posterior static restraints of shoulder associated with it. Traditionally, injuries to the posterior capsule have been difficult to diagnose and visualize with magnetic resonance imaging preoperatively, and very little literature regarding arthroscopic repair of posterior capsular tears exists currently. Indications: We present a repair of a posterior midcapsular and posterior labral tear in a 26-year-old man with recurrent left posterior shoulder instability using a novel all–arthroscopic technique. Technique Description: We performed a shoulder arthroscopy in a lateral decubitus position with the arm at 45° of abduction using standard posterior viewing and anterior working portals. Diagnostic arthroscopy revealed a large posterior midcapsular rupture approximately 2 cm lateral to the glenoid with an associated posterior labral tear. We created an accessory posterolateral portal with needle localization that was outside the capsular defect yet allowed access to the posterior labrum. Anatomic closure of the capsular tear was achieved arthroscopically with 3 interrupted No. 2 nonabsorbable sutures in a side–to–side fashion. Posterior labral repair and capsular shift were done to further address the instability using 2 knotless all–suture anchors percutaneously placed at the 7 o'clock and 9 o'clock position. We closed the posterior portal with a combination of curved and penetrating suture passers. Incisions were closed with interrupted 4-0 nylon. Postoperatively, the patient was placed in an ultra–sling for 4 weeks before physical therapy. We allowed light strengthening at 8 weeks, full strengthening at 12 weeks, and estimated return to sport at 4 months. Results: At 6 months postoperatively, the patient has regained symmetric motion, full strength, and has no residual pain or instability. Conclusion: Gross posterior instability is a rare and difficult condition to diagnose and manage. If no significant labral injuries are identified, injury to the posterior capsule must be considered and full assessment should be done when visualizing from the anterior portal. Repair of the posterior capsule is necessary and can be achieved all arthroscopically with this technique.

Arthroscopic Distal Tibial Allograft for Posterior Glenoid Reconstruction

Background: Posterior glenoid bone loss occurs in more than two-thirds of patients with posterior glenohumeral instability, with 14% to 22% having greater than subcritical bone loss (13.5%), a marker for potential need for bony augmentation versus soft tissue-only procedures. Several techniques are described to augment either the version or volume of the glenoid surface including osteotomies, autograft transfers, and allograft tibia transfers. Indications: Arthroscopic-assisted allograft distal tibia bone block augmentation to the posterior glenoid is indicated for revision posterior instability procedures with posterior bone loss and in primary cases of posterior instability with critical bone loss. Technique Description: Arthroscopic posterior glenoid reconstruction with allograft distal tibia and posterior labral repair in the lateral position is presented. This technique uses standard instrument sets and requires no patient repositioning. The preplanned tibial bone block is prepared on a back table either prior to, or concurrently with, arthroscopic procedure. After creation of high posterior portal and standard anterior portal, a sucker-shaver and burr are used to create a perpendicular edge for apposition of the allograft tibia. The bone block is introduced through a longitudinal incision and underdelivered to the prepared surface under the liberated labrum. The articular surface of the graft and glenoid are aligned and cannulated screws are used to compress the bone block against the native glenoid. The posterior labral tissue is then mobilized over the graft and repaired to the native glenoid. Results: Arthroscopic distal tibial allograft augmentation for posterior bone loss restored stability and function in a small cohort of patients. Patients reported improved stability in the immediate postoperative course, with restoration of motion by 2 months. Push-ups, pull-ups, and return to full active duty without restrictions is allowed at 6 months postoperatively. Imaging at 3 months postoperatively has shown excellent graft healing. Discussion: The benefits of allograft tibia augmentation for posterior instability with glenoid bone loss include an anatomic joint surface restoration including articular cartilage, lack of donor site morbidity, and a minimally invasive approach. When performed arthroscopically, this technique permits concurrent posterior labral repair and anatomic reconstruction.

Anterior and posterior glenoid bone augmentation options for shoulder instability: state of the art

Bony lesions are highly prevalent in anterior shoulder instability and can be a significant cause of failure of stabilisation procedures if they are not adequately addressed. The glenoid track concept describes the dynamic interaction between the humeral head and glenoid defects in anterior shoulder instability. It has been beneficial for understanding the role played by bone defects in this entity. As a consequence, the popularity of glenoid augmentation procedures aimed to treat anterior glenoid bone defects; reconstructing the anatomy of the glenohumeral joint has risen sharply in the last decade. Although bone defects are less common in posterior instability, posterior bone block procedures can be indicated to treat not only posterior bony lesions, attritional posterior glenoid erosion or dysplasia but also normal or retroverted glenoids to provide an extended glenoid surface to increase the glenohumeral stability. The purpose of this review was to analyse the rationale, current indications and results of surgical techniques aimed to augment the glenoid surface in patients diagnosed of either anterior or posterior instability by assessing a thorough review of modern literature. Classical techniques such as Latarjet or free bone block procedures have proven to be effective in augmenting the glenoid surface and consequently achieving adequate shoulder stability with good clinical outcomes and early return to athletic activity. Innovations in surgical techniques have permitted to perform these procedures arthroscopically. Arthroscopy provides the theoretical advantages of lower morbidity and faster recovery, as well as the identification and treatment of concomitant pathologies.

Differences in Outcomes Between Anterior and Posterior Shoulder Instability After Arthroscopic Bankart Repair: A Systematic Review and Meta-analysis

Background: The glenohumeral joint is one of the most frequently dislocated joints in the body, particularly in young, active adults. Purpose: To conduct a systematic review and meta-analysis to evaluate and compare outcomes between anterior versus posterior shoulder instability. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was performed using the PubMed, Cochrane Library, and MEDLINE databases (from inception to September 2019) according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were included if they were published in the English language, contained outcomes after anterior or posterior shoulder instability, had at least 1 year of follow-up, and included arthroscopic soft tissue labral repair of either anterior or posterior instability. Outcomes including return-to-sport (RTS) rate, postoperative instability rate, and pre- and postoperative American Shoulder and Elbow Surgeons (ASES) scores were recorded and analyzed. Results: Overall, 39 studies were included (2077 patients; 1716 male patients and 361 female patients). Patients with anterior instability had a mean age of 23.45 ± 5.40 years (range, 11-72 years), while patients with posterior instability had a mean age of 23.08 ± 8.41 years (range, 13-61 years). The percentage of male patients with anterior instability was significantly higher than that of female patients (odds ratio [OR], 1.36; 95% CI, 1.04-1.77; P = .021). Compared with patients with posterior instability, those with anterior instability were significantly more likely to RTS (OR, 2.31; 95% CI, 1.76-3.04; P < .001), and they were significantly more likely to have postoperative instability (OR, 1.53; 95% CI, 1.07-2.23; P = .018). Patients with anterior instability also had significantly higher ASES scores than those with posterior instability (difference in means, 6.74; 95% CI, 4.71-8.77; P < .001). There were no significant differences found in postoperative complications between the anterior group (11 complications; 1.8%) and the posterior group (3 complications; 1.6%) (OR, 1.12; 95% CI, 0.29-6.30; P = .999). Conclusion: Patients with anterior shoulder instability had higher RTS rates but were more likely to have postoperative instability compared with posterior instability patients. Overall, male patients were significantly more likely to have anterior shoulder instability, while female patients were significantly more likely to have posterior shoulder instability.

Clinically Reliable Knee Flexion Angle Measured on Stress Radiography for Quantifying Posterior Instability in Posterior Cruciate Ligament Injury

Background: After posterior cruciate ligament injury, stress radiography is a common method of quantifying posterior instability, defined as the side-to-side difference in posterior tibial displacement (PTD) between the injured knee and contralateral noninjured knee. However, no study has evaluated the reliability of PTD according to knee flexion angle (KFA) measurements on stress radiographs. Purpose: To evaluate the test-retest reliability of stress radiographic measurements of the KFA in the noninjured knee. In addition, we established a reliable range of KFAs to indicate posterior instability by comparing results with the instability measured at 90° KFA, which is considered the gold standard. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: We evaluated patients who had undergone bilateral stress radiographic examinations at least 5 times for ligament injuries between January 2013 and November 2019. All examinations were performed on a Telos device with a 150-N posterior load. A total of 120 knees and 644 stress radiographs were enrolled. We measured the KFA and PTD on stress radiographs and evaluated the reliability of repeated PTD measurement and the correlation between KFA and PTD. Results: The distribution of the actual noninjured knee KFA ranged from 56.9° to 106.7°. Among the 644 radiographs, 155 (24.1%) showed KFAs between 85° and 95°, and 287 (44.6%) showed KFAs between 80° and 85°. A significant correlation was found between KFA and PTD ( P < .001), and the intrapatient intraclass correlation coefficient (ICC) was 0.788. A KFA range of 85° to 92° satisfied the criteria of high ICC (0.885) and nonsignificant correlation between KFA and PTD ( P = .055) and thus was considered a reliable range of KFAs for quantifying posterior instability. We found no significant risk factors for measurement error, including age ( P = .674), sex ( P = .328), height ( P = .957), weight ( P = .248), or body mass index ( P = .257). Conclusion: We found high reproducibility of posterior displacement measurements on Telos stress radiography at a KFA of 85° to 92° in noninjured knees.