Diagnosis of traumatic shoulder arthrotomies using saline load test with intra-articular pressure monitoring

The purpose of this study was to investigate the amount of saline required to identify a positive traumatic shoulder arthrotomy in a cadaveric model. In addition, intra-articular pressure monitoring was conducted to confirm needle placement and evaluate peak pressure curves prior to capsular failure.

We conducted a cadaveric study using thirty fresh-frozen upper extremities with maintained glenohumeral joint. A shoulder arthrotomy was made in the deltopectoral interval using a 4.4-mm trocar. The joint was loaded using an 18-gauge spinal needle inserted posteriorly and attached to a pressure monitoring system. Fluid was introduced at a uniform rate of 1 cc/sec until active extravasation was visualized from the anterior arthrotomy site. Statistical analysis included assessment of distribution, ANOVA and linear regression.

A positive joint challenge was obtained in all specimens (n = 30) within a maximum of 59 ml of fluid (mean 28 ml, STD 15.4). Average intra-articular pressure at visualization (PAV) was 166.8 mmHg (min., 107; max., 268). In twelve specimens, peak pressures (PP) exceeded PAV, showing a corresponding fall in pressure prior to visualization (ΔPP-PAV = 16.5). To reach a sensitivity of 90% and 95% of arthrotomies, 50 and 58 ml of fluid had to be injected.

Results demonstrated 58 ml of fluid was required to identify a majority of shoulder arthrotomies. Intra-articular pressure monitoring identified successful needle placement. Pressure curve analysis could identify capsular failure before fluid extravasation visualization which could enhance clinical identification and treatment of traumatic shoulder arthrotomies.

Level IV Diagnostic.