Z-effect after intramedullary nailing systems for trochanteric femur fractures

PURPOSE

The aim of this study was to investigate the incidence of Z-effect after dual lag screw intramedullary nailing systems and risk factors contributing to this effect. We hypothesized that long nails provide more neck strength due to a longer lever than short nails and are therefore less likely to develop a misbalance of a higher head compressive strength than neck compressive strength.

METHODS

In this retrospective cohort study 103 patients treated operatively with a dual lag screw intramedullary nailing device for (sub)trochanteric hip fracture were included. We analysed patient charts regarding patient and operation characteristics. Furthermore we conducted radiologic measurements within the 2-year follow-up period to investigate the quality of fracture fixation, implant failure and predictors for Z-effect. The re-operation risk was investigated with multivariate regression analysis.

RESULTS

The incidence of (reversed) Z-effect in this study was 9% (n = 80); 6 out of 7 Z-effects occurred in the short nail group, which was not significant. Patients who were treated with a long nail had a significant larger number of complications in comparison with the short nail group (median 2 vs 0.5, p = 0.001). The long nail group received more often erythrocytes blood transfusions (82% vs 31%, p < 0.01) and had a longer hospital stay (13 vs 21 days, p < 0.05). Migration of lag screws (p <0.05) and unstable fracture type (p < 0.05), were risk factors for re-operation. The re-operation rate within 2 year after surgery was 21%, of which one fourth was due to a Z-effect.

CONCLUSION

The nail length was not associated with the development of a Z-effect. Migration of lag screws after intramedullary nailing is common and a risk factor for re-operation.

Interpretation of Post-operative Distal Humerus Radiographs After Internal Fixation: Prediction of Later Loss of Fixation

PURPOSE

Stable fixation of distal humerus fracture fragments is necessary for adequate healing and maintenance of reduction. The purpose of this study was to measure the reliability and accuracy of interpretation of postoperative radiographs to predict which implants will loosen or break after operative treatment of bicolumnar distal humerus fractures. We also addressed agreement among surgeons regarding which fracture fixation will loosen or break and the influence of years in independent practice, location of practice, and so forth.

METHODS

A total of 232 orthopedic residents and surgeons from around the world evaluated 24 anteroposterior and lateral radiographs of distal humerus fractures on a Web-based platform to predict which implants would loosen or break. Agreement among observers was measured using the multi-rater kappa measure.

RESULTS

The sensitivity of prediction of failure of fixation of distal humerus fracture on radiographs was 63%, specificity was 53%, positive predictive value was 36%, the negative predictive value was 78%, and accuracy was 56%. There was fair interobserver agreement (κ = 0.27) regarding predictions of failure of fixation of distal humerus fracture on radiographs. Interobserver variability did not change when assessed for the various subgroups.

CONCLUSIONS

When experienced and skilled surgeons perform fixation of type C distal humerus fracture, the immediate postoperative radiograph is not predictive of fixation failure. Reoperation based on the probability of failure might not be advisable.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic III.

Adjustable silicone gastric banding: can We continue the original technique of Kuzmak?

BACKGROUND

Kuzmak developed a horizontal gastroplasty for morbid obesity using his adjustable silicone gastric banding (ASGB). The aim of this study was to evaluate the efficiency at weight loss, early and late morbidity and mortality.

METHOD

The records of 44 patients (mean age 36 years) were reviewed. The indication for ASGB was a BMI >40 (group A = 37 patients) or a BMI between 35 and 40 with obesity-related morbidity (group B = 7 patients). The mean preoperative BMI was 44 (+/-5). The paired t test was used to evaluate the BMI.

RESULTS

Early complications occurred in 5 patients: splenic injury (n = 1), aspiration pneumonia (n = 1), wound infection (n = 1), gastric perforation (n = 2); mortality was 2%. Late complications occurred in 19 patients: 17 patients (39%) had a functional stenosis with pouch dilatation (FSPD) and 6 patients had an injection port leakage (14%). At the 1-year follow-up, the mean BMI (of the 39 patients available) was 30 (+/-5) and remained stable. At 36 months, 54% of group A and 100% of group B had a BMI <30.

CONCLUSION

The original technique of Kuzmak is effective to lose weight. However the technique must be adjusted in order to decrease the unacceptable high incidence of FSPD.