2025 ISAKOS Congress in Munich, Germany

2025 ISAKOS Biennial Congress Paper


Does Arthrogenic Muscle Inhibition Exist Before and After Knee Arthroplasty?

Alexandre Le Guen, MD, Toulouse FRANCE
Vincent Marot, MD, Toulouse FRANCE
Emilie Berard, MD, Toulouse FRANCE
Sébastien Parratte, MD, PhD, Prof., Abu Dhabi UNITED ARAB EMIRATES
Etienne Cavaignac, MD,PhD, Toulouse FRANCE

CHU PURPAN, Hopital Pierre Paul Riquet, Toulouse, FRANCE

FDA Status Not Applicable

Summary

AMI needs to be considered before and after TKA, with a relatively high incidence observed, with severe cases in over 10% of cases.

Abstract

Introduction

Arthrogenic Muscle Inhibition (AMI) is described as an enduring inability to achieve correct motor activation of the quadriceps. It can lead to durable complications such as fixed flexion contracture, persistent pain or abnormal gait pattern. If AMI has been described and quantify before and after ACL surgery, only limited data exist about AMI and knee arthroplasty. Our hypothesis was that AMI can be observed in patients with osteoarthritis and after knee arthroplasty procedure. The aims of this study were 1) to measure the prevalence of pre-operative AMI for patients candidate for a knee arthroplasty surgery 2) to measure the incidence of AMI 15 days and 90 days after knee arthroplasty for patient free of pre-operative AMI and 3) to assess the risk factors of AMI after knee arthroplasty.

Material And Methods

This international, multi-centre, prospective study enrolled patients undergoing knee arthroplasty in Toulouse, Abu Dhabi and Andorra. Patients with structural nerve or muscle lesions and patients operated on for simultaneous bilateral knee arthroplasty were excluded. 316 patients were included of which, patients free of pre-operative AMI, were analyzed for postoperative incidence and risk factors. Patients were assessed by experienced knee arthroplasties surgeons using the SANTY classification to detect AMI preoperatively on the day of surgery, 15 days and 3 months after surgery.

Results

Preoperative prevalence of AMI >=1 was 13% [95% Confidence Interval:9-17] (N=41/316). At 2 weeks, the incidence of AMI>=1 after knee arthroplasty was 36% [95% CI:30-42] (N=99/275). 13% of the patients presented a severe AMI (2A: 4% or 2B:9%) described as a severe inability to achieve proper motor activation of the quadriceps and flexion contracture.
Multivariate analysis showed that: effusion, gender (women), post operative flexion contracture, high post operative pain scores and a long time between the beginning of the knee symptoms and surgery were independently and significantly associated with AMI >= 1 at 2 weeks.

Conclusion

The results of this study showed that AMI does exist pre and postoperatively. The relatively high incidence observed postoperatively, with severe cases and flexion contracture in over 10% of the patients, highlights the fact that this condition needs to be considered. Further studies are needed to better understand how to avoid this condition before and after knee arthroplasty.