Is Training With Gym Machines Safe After Hip Arthroplasty?—An In Vivo Load Investigation

Abstract

Background: Training with gym machines is one of the most popular physical activities after total hip arthroplasty (THA). However, to date, there are no evidence-based recommendations for physical activity after THA, worldwide. The aim of the study is to evaluate the in vivo hip joint loads during exercises on four widely used gym machines in order to provide a source for an evidence-based patient counselling for arthroplasty surgeons.Methods: The in vivo hip joint loads in seven patients (59.6 ± 6.4 years, 28.6 ± 2.1 kg/m2) with instrumented hip implants were assessed. The resulting force (Fres), bending moment (Mbend), and torsional moment (Mtors) were evaluated during the training on leg curl/leg extension machines (loads: 20, 30, and 40 kg), leg press machine [backrest: 10°, 30°, and 60°; load: 50, 75, and 100%BW (bodyweight)], and a rope pull machine (abduction/adduction/flexion/extension; each ipsi- and contralateral; load 10 kg). These loads were compared with the loads during walking on treadmill at 4 km/h (median peak values: Fres 303%BW, Mbend 4.25%BWm, and Mtors 2.70%BWm).Results: In each of the four performed exercises with a total of 23 different load conditions or exercise modes analyzed, a significantly lower or not different load was detected with respect to Fres, Mbend, and Mtors measured while walking with 4 km/h. Nevertheless, Fres and Mbend demonstrated a trend to increased loading during the ipsilateral monopod standing rope pull exercises hip flexion, extension, and abduction.Conclusion: Based on our investigation, we assume that the investigated gym machines and external loads can be considered mainly as low-impact sports (with some exceptions) and thus as safe physical activity after THA. Due to the fact that the examinations were conducted in the mean 17.4 months after THA, the applicability of the results to the immediate postoperative period is limited.

Bioelectronic multifunctional bone implants: recent trends

“…1 f), such that the in vivo data could be used to optimize biomechanical models and implant designs, as well as to perform preclinical tests and track the rehabilitation process (Peres et al 2022b ; Soares dos Santos et al 2014 ; Torrão et al 2015 ). Although the positive impact of these technologies is unquestionable (Haffer et al 2022 ; Trepczynski et al 2021 ), their performance cannot be changed after arthroplasty (Peres et al 2022b ; Sousa et al 2021 ): non-optimized performances will always be observed because personalized bone-implant interations are not supported, as recently proved by Soares dos Santos et al ( 2015 ). Indeed, this type of implants is not able to detect bone-implant interface states and to use such data to perform therapeutic actuations on peri-implant regions (Soares dos Santos et al 2016b , 2019 ; Sousa et al 2021 ).…”

“…Data transfer operations between implants and extracorporeal systems are already well established for instrumented passive implants (Graichen et al 1996 , 2007 ; Haffer et al 2022 ; Heinlein et al 2007 ; Soares dos Santos et al 2014 ; Torrão et al 2015 ; Trepczynski et al 2021 ; Westerho et al 2009 ). Even so, three relevant innovations must be emphasized: Activation circuits were already developed to activate/deactivate embedded components of the powering system (Morais et al 2009 ; Morais et al 2013 ).…”

“…Data transfer operations between implants and extracorporeal systems are already well established for instrumented passive implants (Graichen et al 1996(Graichen et al , 2007Haffer et al 2022;Heinlein et al 2007;Soares dos Santos et al 2014;Torrão et al 2015;Trepczynski et al 2021;Westerho et al 2009). Even so, three relevant innovations must be emphasized:…”