Introduction After surgical treatment of injuries of the lower extremity, partial weight bearing is often suggested until soft tissue consolidation. It is doubtful, if this recommendation can be implemented, even in the case that a patient is performing partial weight bearing with a physical therapist. Consequently the question remains, if patients are able to implement partial weight bearing after surgery and which factors favor incompliance. Materials and methods 49 patients, who underwent surgical treatment after injuries of the lower extremity, were equipped with electronic shoe insoles on both sides. Different weight bearing instructions were given depending on the type of injury and surgery (full weight bearing vs. 20 kg weight bearing vs. non-weight bearing). Besides loading, other factors like age, gender, weight and physical activity were evaluated. Statistical analysis was performed using Chi-square and Fisher's exact test with significance set at a p value < 0.05. Results 25 of the 40 patients, who had to perform non-or partial weight bearing, were not able to follow postoperative instructions (compliance rate 37.5%). The average loading of the whole collective was 32.6 kg (4.8-109.2 kg). The specification of loading had no statistically significant influence on real loading (p-value 0.39). Elderly patients were less able to follow instructions than younger patients (36 vs 30.2 kg). Physically active compared to non-active patients overloaded their injured extremity (37.8 vs 28.7 kg). Patients with a high body mass index (BMI) encountered more difficulties to perform partial weight bearing than lightweight patients (36.9 vs 25.1 kg). Conclusions Most patients were not able to follow loading limitation, even a few days after surgery and even if the patients were trained by a physiotherapist. Excessive weight bearing-related complications should be evaluated.

Purpose In order to prevent implant failure and secondary fracture dislocation, it is often recommended that patients perform partial weight-bearing after surgery of the lower extremity. Previous examinations showed that patients are often not able to follow these instructions. In this study, patients who had undergone surgery of the lower extremity were studied in order to analyze whether incorrect loading influenced the number and severity of complications. Methods Fifty-one patients were equipped with electronic shoe insoles, which measure loading and other parameters. The measurement period was 24 to 102 hours. Median duration of follow-up was 490 days. The primary outcome parameter was postoperative complications leading to revision surgery. Statistical analysis was performed using the chi-square and Fisher exact tests with significance set at a p < 0.05. Results Seven out of fifty-one patients had postoperative complications. Four wound complications, one implant failure, chronic instability after fracture of the tibia, and one implant loosening of a hip prosthesis were recorded. In total, 26 of 39 patients were not able to follow the postoperative instructions. Five of the twenty-six patients with difficulties in partial weight-bearing suffered a postoperative complication. In comparison, only 2 of the other 25 patients were affected. There was no statistically significant correlation between high weight-bearing and occurrence of complications (p = 0.29). Conclusion Most of the patients were unable to follow the surgeon’s instructions for partial weight-bearing. Excessive loading did not seem to influence the number and severity of postoperative complications, especially regarding implant failure. Therefore, we should continue with measurements and reevaluate the “partial weight-bearing doctrine”.