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191 Isokinetic deficits at 6 months after ACL reconstruction influence the rate of reinjuries and activity level
  1. Renato Andrade1,2,3,
  2. José Dias1,
  3. Cátia Cardoso1,
  4. Cristina Valente2,
  5. Rogério Pereira1,2,3,4,
  6. Alexandre Rebelo-Marques1,2,5,6,7,
  7. Tiago Proença8,
  8. Pedro Lamas8,
  9. Nuno Cordeiro12,13,
  10. Alcindo Silva9,
  11. João Espregueira-Mendes1,2,10,11
  1. 1Clínica do Dragão, Espregueira-Mendes Sports Centre – FIFA Medical Centre of Excellence, Porto, Portugal
  2. 2Dom Henrique Research Centre, Porto, Portugal
  3. 3Faculty of Sports, University of Porto, Porto, Portugal
  4. 4Escola Superior de Saúde, Universidade Fernando Pessoa, Porto, Portugal
  5. 5Faculty of Medicine, University of Coimbra, Coimbra, Portugal
  6. 6Clinical Academic Center of Coimbra, Coimbra, Portugal
  7. 7Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
  8. 8Fisiocinética – Centro Isocinético, Porto, Portugal
  9. 9Hospital da Luz – Arrábida, Vila Nova de Gaia, Portugal
  10. 10ICVS/3B’s-PT Government Associate Laboratory, Braga/Guimarães, Portugal
  11. 11Escola de Medicina, Universidade do Minho, Braga, Portugal
  12. 12Instituto Politécnico de Castelo Branco, Castelo Branco, Portugal
  13. 13AGE.COMM, Castelo Branco, Portugal


Background Recent evidence suggests that athletes may not be prepared to return to sport at 6 months following an anterior cruciate ligament (ACL) reconstruction.

Objective Identify knee isokinetic neuromuscular deficits at 6 months after ACL reconstruction and assess if deficits impact on the rate of new knee injuries and level of activity.

Design Retrospective study.

Setting Recreational and competitive athletes.

Patients (or Participants) Fifty-eight patients (27.1±7.1 years old; 79% male) that underwent ACL reconstruction (62% hamstrings and 38% bone-patellar-tendon-bone grafts) and that performed the knee isokinetic testing at 6 months.

Interventions (or Assessment of Risk Factors) Bilateral knee isokinetic assessment at 6 months, 6 and 8 Con/Con repetitions, at 60°/s and 180°/s, respectively.

Main Outcome Measurements Peak torque of knee extensors and flexors at 60°/s and 180°/s and Con/Con unilateral ratio. Prevalence of bilateral (>10%) and unilateral ratio (<0.47 and >0.80) abnormalities. The level of activity (Tegner) and number of new knee injuries (ACL or other knee injury).

Results Fifty-two participants (90%) had bilateral deficits at 60°/s, 74% and 59% for knee extensors and flexors, respectively. Unilateral abnormalities were present on 16% of participants at 60°/s and 180°/s. Thirty-seven participants had 2 or more years follow-up (28 hamstrings and 9 bone-patellar-tendon-bone graft). From these, there were 4 new ACL injuries (75% contralateral) and 8 other knee injuries (50% contralateral). Rate of new knee injuries was more frequent on hamstrings graft (25% vs 10%). Those with bilateral deficits at 60°/s (n=31) had higher rate of new knee injuries (23% vs 17%) and higher rate of Tegner level decrease (45% vs 17%).

Conclusions We found an unacceptably high rate of participants (90%) display knee isokinetic bilateral deficits at 60°/s at 6 months after ACL reconstruction. Bilateral deficits seem to influence the rate of new knee injuries and Tegner activity level.

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