Indice articoli

Results

Between February 2005 and January 2011, 65 hips (64 patients) underwent acetabular reconstruction with the use of TM cup associated with augments. Of these, 9 were excluded because of the preoperative diagnosis: “one-stage” and “two-stage” THA reimplantation for infection in 2 and 3 hips respectively, Girdlestone in 3, and chronic hip displacement in 1. One hip with a preoperative diagnosis of aseptic loosening was excluded because the patient died of pneumonitis 18 months after surgery.

Finally, 55 hips (54 patients) were included in the study. According to the classification of Paprosky et al [20], a Paprosky type IIIA defect was found in 42 hips, whereas a Paprosky type IIIB defect was present in 13 hips. No patients had pelvic discontinuity. Of those, 30 underwent revision of the acetabular component alone, 25 received a total revision surgery. Patients included 18 men and 36 women, with an average age of 63.5 years (range, 35–86) at the time of surgery. The average body mass index was 26.1 kg/cm2 (range, 19.5–40). The mean follow-up was 53.7 months (range, 36–91). No patients were lost to follow-up, but one 73 year-old woman died 44 months after surgery because of encephalitis.

The average HHS increased from 40 (range, 27–52) preoperatively to 90.5 (range, 61–100) at the last follow-up (P < 0.0001). The final scores were excellent in 37 hips, good in 12, modest in 5, and poor in 1. The average value of flexion changed from 83° (range, 45°–100°) before surgery to 117° (range, 80°–130°) at the last follow-up (P < 0.0001); abduction changed from 27° (range, 10°–45°) to 40° (range, 20°–50°) (P < 0.0001); adduction changed from 17° (range, 0°–30°) to 31° (range, 15°–45°) (P < 0.0001); internal rotation changed from 12° (range, 0°–20°) to 23° (range, 10°–35°) (P < 0.0001); and external rotation changed from 21° (range, 5°–30°) to 35° (range, 20°–45°) (P < 0.0001). Clinical picture after surgery was rated as very satisfactory by 33 patients, satisfactory by 18 patients, moderately satisfactory by 3 patients, and unsatisfactory by 1 patient.

Preoperative assessment of the acetabular bone defect according to the classification of Paprosky et al [20] showed a very good intratester (tester 1: weighted K = 0.89, P < 0.0001; tester 2: weighted K = 0.93, P < 0.0001) and intertester agreement (weighted K = 0.86, P < 0.0001).

The mean preoperative LLD was 16.6 mm of shortening (43 mm to 6 mm short) on the affected side, while the postoperative mean LLD was 1 mm of shortening (8 mm short to 6 mm long) (P < 0.0001). The mean vertical position of COR from the interteardrop line changed from 42.3 mm (range, 22–63 mm) preoperatively to 25.7 mm (range, 17–44 mm) postoperatively (P < 0.0001). The mean horizontal position of COR from the teardrop changed from 37.8 mm (range, 15–61 mm) preoperatively to 39.2 mm (24–53 mm) postoperatively (P > 0.05).

Radiological loosening of the acetabular components was found in 3 (5.4%) out of the 55 hips. Radiolucent lines were noted in 3 (5.4%) out of the 55 hips. Of these, two patients showed a 1 mm line in zone 1 and 2 at 6 and 24 months from surgery respectively, whereas one had a 1 mm line crossing three acetabular zones at 12 months after surgery. In all patients, radiolucencies were not progressive at the latest follow-up. Heterotopic ossification was found in 11 (20%) out of the 55 hips. Of these, 7 patients showed a grade I of ossification according to Brooker, 2 a grade II, and 2 a grade III. No patients required further surgery for ossification's removal.

Follow-up data were available for all the patients included. With a mean follow-up of 53.7 months, 4 (7.3%) out of 55 hips underwent acetabular components revision surgery. The survival rate at 2 and 5 years was 96.4% and 92.8%, respectively. The mean implant survival was 85.8 months (95% CI: 80.9–90.8), whereas the median implant survival was unreached in our population (Fig. 3).

Fig. 3
Fig. 3.

Kaplan–Meier analysis: cumulative prosthesis survival calculated with 95% confidence intervals. The vertical hatches on the curve represent the censored patients: participants who dropped out of the study or who did not develop the event by the end of the study.

Among the four patients who underwent acetabular components revision surgery, one 51 year-old woman developed aseptic loosening of the cup with hip dislocation after 30 months from surgery (Fig. 4). Since the augment was still fixed to the bone at the time of revision surgery, she received a revision shell with a cemented liner without removal of the augment. One 61 year-old woman showed aseptic loosening of the cup and augment at 17 months from surgery (Fig. 5), and underwent second revision to change both shell and augment. Subsequently, she developed aseptic loosening of the cup with dislocation of the prosthesis after 16 months, and underwent third revision with Ganz's cage and tantalum-coated cup used as augmentation. One 52 year-old man showed aseptic loosening of the cup and augment after 38 months from surgery (Fig. 6), and underwent revision of both shell and augment. Finally, one 53 year-old woman developed recurrent instability after 2 months from surgery, and underwent total revision associated with shortening of the femur.

Fig. 4
Fig. 4.

Aseptic loosening of the cup with hip dislocation at 30 months after surgery in a 51 year-old woman. The radiograph (AP view) shows superior lateral migration of the hip COR, retroacetabular and ischial osteolysis, and screw breakage. A 10-cm reference line is reported.

Fig. 5
Fig. 5.

Aseptic loosening of the cup and augment at 17 months after surgery in a 61 year-old woman. The radiograph (AP view) shows superior medial migration of the hip COR, interruption of Kohler's line, ischial osteolysis, and screw breakage. A 10-cm reference line is reported.

Fig. 5
Fig. 6.

Aseptic loosening of the cup and augment at 38 months after surgery in a 52 year-old man. The radiograph (AP view) shows superior medial migration of the hip COR, interruption of Kohler's line with the cup moving into the pelvis, and severe ischial osteolysis. A 10-cm reference line is reported.

Of note, a 62 year-old woman had further surgery without revision of acetabular implants, because of a periprosthetic fracture managed with revision of femoral component alone and additional fixation with cable.

No cases of deep venous thrombosis, pulmonary embolism or death were reported as a result of the surgical procedure.


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GAP II

GAP II è un sistema per l’archiviazione di dati clinici e chirurgici di pazienti sottoposti ad interventi di chirurgia protesica di anca, ginocchio e spalla.