Assessment of biomechanical parameters of the shoulder joint at the operated side versus non-operated side in patients treated surgically for breast cancer.

Aim: Isokinetic assessment of biomechanical parameters of the shoulder joint at the operated side versus non-operated side in patients treated surgically for breast cancer according to the type of surgery performed.

Background: Despite significant progress in medicine, comprehensive cancer therapy may still cause a number of undesired structural and functional effects. The most frequent complications include long-term weakening of muscles within the shoulder and upper extremity at the operated side.

Materials and methods: The study enrolled 57 patient, divided into two groups: mastectomy and BCT. Diagnostic tests were carried out on the groups to assess biomechanical parameters (peak torque, power, total work) of the shoulder joint in internal and external rotation.

Results: The results of the isokinetic test revealed a considerable reduction of dynamic properties of the muscle groups responsible for the function of the shoulder joint at the operated side. The deficits observed, depending on the angular speed and plane of rotation, were from 22.3% to 32.7% and from 23.1% to 29.4% for muscle power and total work, respectively. The least noticeable loss was that of muscular torque, ranging from 6.5% to 18.3%.

Conclusion: None of the treatment methods applied ensured a full release of the restriction within the shoulder and upper limb. The deficits observed may constitute a serious disorder of the musculoskeletal system; therefore, a clinical study of biomechanical parameters of the shoulder joint may be an important control of patients' functional status after breast cancer treatment.