Clinical Outcomes Following Distal Femur Replacement for Periprosthetic Distal Femur Fractures: A Systematic Review and Meta-Analysis.

BACKGROUND: Management of periprosthetic distal femur fractures (PDFFs) is often complicated by poor bone quality and limited bone stock making fixation attempts challenging and prone to failure. Distal femoral replacement (DFR) is being used to treat such injuries although outcome data are mostly from small case series. We sought to systematically review the literature on DFR for PDFF to summarize their outcomes. METHODS: PubMed, MEDLINE (EBSCO), and Cochrane Central Database were searched to identify reports of PDFFs treated with DFR. Articles reporting on 5 or more knees were systematically reviewed for clinical function, complications, and mortality. Random effects meta-analysis was used to create summary estimates and publication bias also assessed. RESULTS: Of 287 identified and screened articles, 15 were included, 14 retrospective, reporting on 352 knees. Following DFR, 87% (95% confidence interval [CI] 71-95) of patients were able to ambulate. The mean postoperative Knee Society Score was 80 (95% CI 77-84). The risk of periprosthetic joint infection was 4.3% (95% CI 2.2-8.2). One-year postoperative mortality rate was 10% (95% CI 6-18). There was some evidence of publication bias with a trend toward smaller studies reporting lower infection risk and mortality. CONCLUSION: DFR for PDFFs is associated with high functional outcomes and a relatively modest risk of infection. The periprosthetic joint infection and 1-year mortality rates reported here should be considered lower bounds estimates due to publication bias and loss to follow-up. Further investigation of long-term outcomes following DFR for PDFFs is warranted though short-term functional outcomes are promising.

The Hawkins Sign of the Talus: The Impact of Patient Factors on Prediction Accuracy.

BACKGROUND: Osteonecrosis is a complication of talar neck fractures associated with chronic pain and poor functional outcomes. The Hawkins sign, the radiographic presence of subchondral lucency seen in the talar dome 6 to 8 weeks after trauma, is a strong predictor of preserved talar vascularity. This study sought to assess the accuracy of the Hawkins sign in a contemporary cohort and assess factors associated with inaccuracy. METHODS: A retrospective review of talar neck fractures at a level-I trauma center from 2008 to 2016 was conducted. Both the Hawkins sign and osteonecrosis were evaluated on radiographs. The Hawkins sign was determined on the basis of radiographs taken approximately 6 to 8 weeks after injury, whereas osteonecrosis was determined based on radiographs taken throughout follow-up. The Hawkins sign accuracy was assessed using proportions with 95% confidence intervals (CIs), and associations were examined with Fisher exact testing. RESULTS: In total, 105 talar neck fractures were identified. The Hawkins sign was observed in 21 tali, 3 (14% [95% CI, 3% to 36%]) of which later developed osteonecrosis. In the remaining 84 tali without a Hawkins sign, 32 (38% [95% CI, 28% to 49%]) developed osteonecrosis. Of the 3 tali that developed osteonecrosis following observation of the Hawkins sign, all were in patients who smoked. CONCLUSIONS: A positive Hawkins sign may not be a reliable predictor of preserved talar vascularity in all patients. We identified 3 patients with a positive Hawkins sign who developed osteonecrosis, all of whom were smokers. Factors impairing the restoration of microvascular blood supply to the talus may lead to osteonecrosis despite the presence of preserved macrovascular blood flow and an observed Hawkins sign. Further research is needed to understand the factors limiting Hawkins sign accuracy. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Talar Neck Fractures With Associated Ipsilateral Foot and Ankle Fractures Have a Higher Risk of Avascular Necrosis.

OBJECTIVES: To determine if talar neck fractures with concomitant ipsilateral foot and/or ankle fractures (TNIFAFs) are associated with higher rates of avascular necrosis (AVN) compared with isolated talar neck fractures (ITNs). DESIGN: Retrospective cohort. SETTING: Single level I trauma center. PATIENT SELECTION CRITERIA: Skeletally mature patients who sustained talar neck fractures from January 2008 to January 2017 with at least 6-month follow-up. Based on radiographs at the time of injury, fractures were classified as ITN or TNIFAF and by Hawkins classification. OUTCOME MEASURES AND COMPARISONS: The primary outcome was the development of AVN based on follow-up radiographs, with secondary outcomes including nonunion and collapse. RESULTS: There were 115 patients who sustained talar neck fractures, with 63 (55%) in the ITN group and 52 (45%) in the TNIFAF group. In total, 63 patients (54.7%) were female with the mean age of 39 years (range, 17-85), and 111 fractures (96.5%) occurred secondary to high-energy mechanisms of injury. There were no significant differences in demographic or clinical characteristics between groups ( P > 0.05). Twenty-four patients (46%) developed AVN in the TNIFAF group compared with 19 patients (30%) in the ITN group ( P = 0.078). After adjusting for Hawkins classification and other variables, the odds of developing AVN was higher in the TNIFAF group compared with the ITN group [odds ratio, 2.43 (95% confidence interval, 1.01-5.84); ( P = 0.047)]. CONCLUSIONS: This study found a significantly higher likelihood of AVN in patients with talar neck fractures with concomitant ipsilateral foot and/or ankle fractures compared to those with isolated talar neck fractures after adjusting for Hawkins classification and other potential prognostic confounders. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Association of Talar Neck Fractures With Body Extension and Risk of Avascular Necrosis.

BACKGROUND: The objective of this study was to determine whether talar neck fractures with proximal extension (TNPE) into the talar body are associated with higher rates of avascular necrosis (AVN) compared to isolated talar neck (TN) fractures. METHODS: A retrospective review of patients sustaining talar neck fractures at a level I trauma center from 2008 to 2016 was performed. Demographic and clinical data were collected from the electronic medical record. Fractures were characterized as TN or TNPE based on initial radiographs. TNPE was defined as a fracture that originates on the talar neck and extends proximal to a line subtended from the junction of the neck and the articular cartilage dorsal to the anterior portion of the lateral process of the talus. Fractures were classified according to the modified Hawkins classification for analysis. The primary outcome was the development of AVN. Secondary outcomes included nonunion and collapse. These were measured on postoperative radiographs. RESULTS: There were 137 fractures in 130 patients, with 80 (58%) fractures in the TN group and 57 (42%) in the TNPE group. Median follow-up was 10 months (interquartile range, 6-18 months). The TNPE group was more likely to develop AVN as compared to the TN group (49% vs 19%, P < .001). Similarly, the TNPE group had a higher rate of collapse (14% vs 4%, P = .03) and nonunion (26% vs 9%, P = .01). Even after adjusting for open fracture, Hawkins fracture type, smoking, and diabetes, AVN still remained significant for the TNPE group as compared to the TN group with an odds ratio of 3.47 (95% CI, 1.51-7.99). CONCLUSION: We found a higher rate of AVN, subsequent collapse, and nonunion in patients with TNPE compared to isolated TN fractures. LEVEL OF EVIDENCE: Level III, retrospective cohort study.