Bone Defects in Anterior Instability of the Shoulder: Diagnosis and Management

Our First experience of Using Biodegradable Implants in Latarjet – Bristow Surgical Procedure at Chronic Posttraumatic Anterior Shoulder Insta

Background. Multi-layer spiral computed tomography shows that the main cause of shoulder instability is glenoid cavity bone defect. The aim of our research was to assess the effectiveness and safety of biodegradable implants in the treatment of patients with chronic posttraumatic anterior shoulder instability under conditions of bone defect of glenoid cavity margin by the restoration of anatomic shape and structure of scapula articular surface.

Materials and methods. We performed a pilot study based on the results of surgical treatment of 7 patients using 4.5 mm biodegradable compressing screws. In preoperative period, all patients had standard two-dimensional X-rays and MSCT with 3D-reconstruction. In postoperative period, all patients had check-up X-ray right after the surgery and MRI in 3 months after the surgery.

Results. The results of the treatment were assessed by common clinical criteria, functional criteria, X-ray evidence and intraand postoperative complications. We registered strong functioning of an arm and an increase in the range of motions. Data from Rowe/Zarins and DASH questionnaires showed that the patients totally recovered. X-ray evidence showed consolidation of non-free autograft to the zone of scapula bone defect without osteolysis or widening of a drilled hole. We did not observe either a failure of union, or any formation of false joint, or any screw fractures in bone tissue. Beyond that, we did not observe any complication in postoperative period and early postoperative complications in particular.

Conclusion. Pilot study with use of modern biodegradable implants in osteoplastic stabilization of shoulder joint at recurring instability showed their effectiveness and safety in patients of young and active working age. However, considering small number of patients in pilot study we cannot extrapolate our results to all similar and analogue cases of using biodegradable implants. In this regard, it is necessary to perform major multicenter clinical randomized study for further long-term observation and detection of possible unwanted side effects.

Measurement of Glenoid Bone Loss With 3-Dimensional Magnetic Resonance Imaging: A Matched Computed Tomography Analysis

PURPOSE

To compare the measurement of glenoid bone surface area (GBSA) and glenoid bone loss (GBL) between 3-dimensional computed tomography (3D CT) and an autosegmentation approach for 3D magnetic resonance imaging (MRI) of patients with recurrent shoulder instability.

METHODS

Eight subjects (2 women and 6 men; age range, 15-72 years [mean, 44 ± 19 years]) were consecutively enrolled who had both CT and MRI of the shoulder for clinical shoulder instability. Inclusion criteria were patients with shoulder instability or other shoulder injury who had both a CT scan and MRI performed of the same shoulder. All patients underwent a 3D CT scan and a 3-Tesla 3D MRI with additional volumetric and autosegmented sequences. En face views of the glenoid for both CT and MRI were auto- and manually measured for overall GBSA and GBL using best-fit circle technique; the amount of GBL was compared with loss of GBSA and was expressed as a percentage of bone loss.

RESULTS

There were no differences in GBL measured by 3D CT (41 mm², 6.6%) vs 3D MRI (40 mm², 6.5%, P = .852). The mean GBSA was not different among the manual- and autocalculated 3D CT (644 mm² vs 640 mm², P = .482). In addition, the manual MRI scan glenoid area was similar to the autocalculated 3D MRI (622 mm² vs 618 mm², respectively; P = .482). Overall regression analysis demonstrated excellent correlation between CT and MRI for both GBSA and GBL calculations (R² = 0.84-0.90).

CONCLUSIONS

3D MRI of the glenoid is nearly identical to 3D CT scans for measurement of GBSA and GBL, making 3D MRI a reliable alternative to a CT scan for a preoperative shoulder evaluation of the glenoid pathology. This study shows that a 3D MRI could be a radiation-free and reliable alternative to a preoperative CT shoulder scan.

LEVEL OF EVIDENCE

Level III, case-control study.

Results of 45 arthroscopic Bankart procedures: Does the ISIS remain a reliable prognostic assessment after 5 years?

PURPOSE

The Instability Severity Index Score (ISIS) includes preoperative clinical and radiological risk factors to select patients who can benefit from an arthroscopic Bankart procedure with a low rate of recurrence. Patients who underwent an arthroscopic Bankart for anterior shoulder instability with an ISIS lower than or equal to four were assessed after a minimum of 5-year follow-up.

METHODS

Forty-five shoulders were assessed at a mean of 79 months (range 60-118 months). Average age was 29.4 years (range 17-58 years) at the time of surgery. Postoperative functions were assessed by the Walch and Duplay and the Rowe scores for 26 patients; an adapted telephonic interview was performed for the 19 remaining patients who could not be reassessed clinically. A failure was defined by the recurrence of an anterior dislocation or subluxation. Patients were asked whether they were finally very satisfied, satisfied or unhappy.

RESULTS

The mean Walch and Duplay score at last follow-up was 84.3 (range 35-100). The final result for these patients was excellent in 14 patients (53.8 %), good in seven cases (26.9 %), poor in three patients (11.5 %) and bad in two patients (7.7 %). The mean Rowe score was 82.6 (range 35-100). Thirty-nine patients (86.7 %) were subjectively very satisfied or satisfied, and six (13.3 %) were unhappy. Four patients (8.9 %) had a recurrence of frank dislocation with a mean delay of 34 months (range 12-72 months). Three of them had a Hill-Sachs lesion preoperatively. Two patients had a preoperative ISIS at 4 points and two patients at 3 points.

CONCLUSION

The selection based on the ISIS allows a low rate of failure after an average term of 5 years. Lowering the limit for indication to 3 points allows to avoid the association between two major risk factors for recurrence, which are valued at 2 points. The existence of a Hill-Sachs lesion is a stronger indicator for the outcome of instability repair.

LEVEL OF EVIDENCE

Level IV, Retrospective Case Series, Treatment Study.

Diagnosis and management of humeral head bone loss in shoulder instability

Humeral head bone defects (Hill-Sachs lesions) are caused by anterior shoulder dislocation with impaction of the posterosuperior humeral head onto the anterior glenoid rim. Frequently, these bony lesions are associated with glenohumeral instability, and large lesions may contribute to recurrent instability after failure of a soft tissue repair. To improve outcomes and minimize the risk of persistent instability, a thorough understanding of the biomechanics of humeral bone loss is required. Detection and quantification of clinically relevant humeral head bone loss are performed through an accurate history, physical examination, and interpretation of imaging studies. The diagnosis and treatment options for reverse Hill-Sachs lesions are discussed, and the various treatment options for Hill-Sachs lesions are reviewed, including operative techniques to limit engagement of the deformity by soft tissue transfer, rotational osteotomy, bone grafting, or osteochondral transplantation.