Midterm Radiographic and Functional Outcomes of the Anterior Subcutaneous Internal Pelvic Fixator (INFIX) for Pelvic Ring Injuries.

OBJECTIVE: To describe our experience using the anterior internal pelvic fixator (INFIX) for treating pelvic ring injuries. DESIGN: Case Series. SETTING: Level 1 Trauma Center. PATIENTS: Eighty-three patients with pelvic ring injuries were treated with INFIX. Follow-up average was 35 months (range 12-80.33). INTERVENTION: Surgical treatment of pelvic ring injuries included reduction, appropriate posterior fixation, and INFIX placement. OUTCOME MEASUREMENTS: Reduction using the pelvic deformity index and pubic symphysis widening, Majeed functional scores, complications; infection, implant failure, heterotopic ossification (HO), nerve injury, and pain. RESULTS: All patients healed in an appropriate time frame (full weight bearing 12 weeks postoperation). The average pelvic deformity index reduction (injury = 0.0420 ± 0.0412, latest FU = 0.0254 ± 0.0243) was 39.58%. The average reduction of pubic symphysis injuries was 56.92%. The average Majeed score of patients at latest follow-up was 78.77 (range 47-100). Complications were 3 infections, 1 case of implant failure, 2 cases implantation too deep, 7 cases of lateral femoral cutaneous nerve irritation, and 3 cases of pain associated with the device. HO was seen in >50% of the patients, correlated with increased age (P < 0.007), injury severity score (P < 0.05) but only 1 case was symptomatic. CONCLUSIONS: The pelvic injuries had good functional and radiological outcomes with INFIX and the appropriate posterior fixation. The downside is removal requiring a second anesthetic, there is a learning curve, HO often occurs, the lateral femoral cutaneous nerve may get irritated which often resolves once the implants are removed. Surgery-specific implants need to be developed. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

INFIX versus plating for pelvic fractures with disruption of the symphysis pubis.

PURPOSE: The purpose of this study is to compare INFIX to plating in the treatment of unstable pelvic ring injuries with disruption of the symphysis. METHODS: Twenty-four patients treated with INFIX were compared to 28 patients fixed by plating. All patients had anterior and posterior fixation. Injuries were classified using the Young and Burgess and AO/OTA classification systems. Reductions of the pelvic ring were assessed using the pelvic deformity index (PDI) and symphyseal widening. Patients were contacted to get functional outcomes using the Majeed scoring system and complications were tabulated . RESULTS: INFIX was inferior to plating at reducing symphyseal widening (INFIX 10.72± 5.0 Plates 6.97 ± 3.39 P = 0.012) but similar in reducing the pelvic deformity index. (INFIX 0.0221± .015 Plates 0.0190 ± .0105 P = 0 .38). Majeed scores were similar 83.95 ± 15.2 (median 89, range 51-100) for INFIX and 77.67± 16.7 (median 79, range 54-100) for plating. Complications included infection (1 (4%) INFIX , 4 (14%) plates), improper hardware placement or failure (2 (8%) INFIX, 3 (11%) plates), and heterotopic ossification (11 (46%) INFIX, 16 (57.1%) plates). Infection in the plated patients was related to urological injury in 3/4 cases. CONCLUSIONS: Plating provides better reduction of the pubic symphysis and requires only one surgery. Outcomes scores were similar. INFIX may be preferable in obese patients, young women of childbearing age or those with urological injury.