No abstract

Background Nontraumatic osteonecrosis of the femoral head (NONFH) is a devastating disease, and the risk factors associated with progression into collapse after core decompression (CD) remain poorly defined. Therefore, we aim to define risk factors associated with collapse-free survival (CFS) after CD of precollapse NONFH and to propose a nomogram for individual risk prediction. Methods According to the baseline characteristics, clinical information, radiographic evaluations, and laboratory examination, a nomogram was developed using a single institutional cohort of patients who received multiple drilling for precollapse NONFH between January 2007 and December 2019 to predict CFS after CD of precollapse NONFH. Furthermore, we used C statistics, calibration plot, and Kaplan-Meier curve to test the discriminative ability and calibration of the nomogram to predict CFS. Results One hundred and seventy-three patients who underwent CD for precollapse NONFH were retrospectively screened and included in the present study. Using a multiple Cox regression to identify relevant risk factors, the following risk factors were incorporated in the prediction of CFS: acute onset of symptom (HR, 2.78; 95% CI, 1.03–7.48; P = 0.043), necrotic location of Japanese Investigation Committee (JIC) C1 and C2 (HR, 3.67; 95% CI, 1.20–11.27; P = 0.023), necrotic angle in the range of 250–299°(HR, 5.08; 95% CI, 1.73–14.93; P = 0.003) and > 299° (HR, 9.96; 95% CI, 3.23–30.70; P < 0.001), and bone marrow edema (BME) before CD (HR, 2.03; 95% CI, 1.02-4.02; P = 0.042). The C statistics was 0.82 for CFS which revealed good discriminative ability and calibration of the nomogram. Conclusions Independent predictors of progression into collapse after CD for precollapse NONFH were identified to develop a nomogram predicting CFS. In addition, the nomogram could divide precollapse NONFH patients into prognosis groups and performed well in internal validation.

Objective: To compare and analyze the clinical outcomes between unstemmed and stemmed constrained condylar knees (CCK) in complex primary total knee arthroplasty (TKA) in terms of implant survivorship, change in outcome evaluations, and complications. Methods:We reviewed 156 consecutive patients who received primary TKA using PFC ® SIGMA ® TC3 (TC3) of constrained condylar design between January 2009 and January 2017 at our institution. After removing patients who met exclusion criteria, 25 patients were identified as unstemmed TC3 cases and 81 as stemmed TC3 cases. Propensity score matching was used to select 25 stemmed cases as a control group for the unstemmed group with comparable preoperative conditions including preoperative demographics, preoperative diagnosis, preoperative range of motion, main reason to use TC3, ASA score (American Society of Anesthesiologists), and follow-up duration. Preoperative and postoperative clinical evaluations including Knee Society Score (KSS), Hospital for Special Surgery (HSS) score, the 12-Item Short-Form Health Survey (SF-12), and the range of motion (ROM) were obtained and compared. The instability, periprosthetic fracture, radiolucent lines, polyethylene wear, and heterotrophic ossification were assessed according to the anteroposterior and lateral radiographs of the knee. The complications and implant survivorship between the two groups were also recorded and compared.Results: 3After the index surgery, both groups showed substantial improvement in KSS (knee and function), HSS score, SF-12, and ROM compared with baseline. There was no significant difference in the mean KSS scores (knee and function), HSS score, SF-12, and ROM between the unstemmed and stemmed group postoperatively. No statistically significant difference was found in the overall complication rate between the two groups. The overall Kaplan-Meier survivorship was 98.0% (95% confidence interval 94.1%-100.0%) at 7 years. No significant difference was found in the survival rate between the unstemmed group (100.0%) and the stemmed group (96.0%) at 7 years (log rank, P = 0.317). The mean duration of follow-up was 7.0 years for unstemmed group and 7.7 years for stemmed group. Conclusions:In patients with adequate bone stock receiving complex primary TKA, unstemmed CCK could achieve similar clinical outcomes at mid-term follow-up as stemmed CCK.