[Medium- and long-term effectiveness of hip revision with SL-PLUS MIA stem in patients with Paprosky type Ⅰ- Ⅲ femoral bone defect].

Objective: To investigate the medium- and long-term effectiveness of hip revision with SL-PLUS MIA stem in patients with Paprosky typeⅠ-Ⅲ femoral bone defect.

Methods: Between June 2012 and December 2018, 44 patients with Paprosky typeⅠ-Ⅲ femoral bone defect received hip revision using SL-PLUS MIA stem. There were 28 males and 16 females, with an average age of 57.7 years (range, 31-76 years). Indications for revision comprised aseptic loosening (27 cases) and periprosthetic joint infection (17 cases). The Harris hip scores were 54 (48, 60) and 43 (37, 52) in patients with aseptic loosening and periprosthetic joint infection, respectively. The preoperative femoral bone defects were identified as Paprosky type Ⅰ in 32 cases, type Ⅱ in 9 cases, type ⅢA in 2 cases, and type ⅢB in 1 case. Operation time and intraoperative blood transfusion volume were recorded. During follow-up after operation, the hip joint function were evaluated by Harris hip score and X-ray films, the femoral stem survival was analyzed, and the surgical related complications were recorded.

Results: The operation time of infected patients was 95-215 minutes, with an average of 125.0 minutes. The intraoperative blood transfusion volume was 400-1 800 mL, with an average of 790.0 mL. The operation time of patients with aseptic loosening was 70-200 minutes, with an average of 121.0 minutes. The intraoperative blood transfusion volume was 400-1 400 mL, with an average of 721.7 mL. All patients were followed up 5.3-10.0 years (mean, 7.4 years). At last follow-up, the Harris hip scores were 88 (85, 90) and 85 (80, 88) in patients with aseptic loosening and periprosthetic joint infection, respectively, both of which were significantly higher than those before operation ( P<0.05). Radiological examination results showed that the distal end of the newly implanted femoral stem did not cross the distal end of the original prosthesis in 25 cases, and all femoral stems obtained bone fixation. Two cases experienced femoral stem subsidence and 1 case had a translucent line on the lateral side of the proximal femoral stem. When aseptic loosening was defined as the end event, the 10-year survival rate of the SL-PLUS MIA stem was 100%. When treatment failure due to any reason was defined as the end event, the survival time of the prosthesis was (111.70±3.66) months, and the 7-year survival rate was 95.5%. The 7-year survival rates were 94.1% and 96.3% in patients with aseptic loosening and periprosthetic joint infection, respectively. The incidence of postoperative complications was 9.1% (4/44), among which the prosthesis related complications were 4.5% (2/44), 1 case of dislocation and 1 case of infection recurrence.

Conclusion: Hip revision with SL-PLUS MIA stem has the advantages of simple operation and few postoperative complications in the patients with Paprosky type Ⅰ-Ⅲ femoral bone defect, and the medium- and long-term effectiveness is reliable.