INTRODUCTION: The last two decades have been leading to the development of several types of surgical techniques and procedures to manage the LHB lesions. This paper analyses and compares the difference in muscle strength pre-and post-operatively in two most commonly used surgical procedures -LHB tenotomy and tenodesis. METHOD: The study includes 68 patients who underwent surgery between 2016 and 2020. The patients who had met the prospective study inclusion criteria were divided into two groups based on type of surgery they had undergone (LHB tenotomy or tenodesis); each group consisted of 34. The muscle strength during elbow flexion was measured preoperatively and postoperatively using the Commander Echo Console ultrasound muscle testing device. All patients enrolled in the study had been assessed for elbow flexion strength preoperatively. The muscle strength was measured preoperatively and then 3 years postoperatively (12 to 60 months) on average. CONCLUSION: The study confirmed that the patients who had undergone LHB tenodesis show a significantly lower decrease in elbow flexion strength and a significantly lower incidence of "Popeye" deformity than the patients after LHB tenotomy. Moreover, in the tenodesis group, it was possible to initiate rehabilitation earlier. The incidence of postoperative complications was almost identical in both groups of patients (Tab. 10, Fig. 6, Ref. 40).