Joint laxity and isokinetic thigh muscle strength characteristics after anterior cruciate ligament reconstruction: bone patellar tendon bone versus quadrupled hamstring autografts

Clin J Sport Med. 2006 Jan;16(1):4-9. doi: 10.1097/01.jsm.0000188040.97135.43.


Objectives: To analyze ligamentous stability and isokinetic strength of knee extensor and flexor muscles after anterior cruciate ligament reconstruction using 2 different autografts with identical fixation.

Design: This study implements a comparative case series design.

Setting: Schulthess Clinic, Switzerland.

Patients: A total of 153 consecutive patients (n = 87 bone-patellar tendon-bone [BPTB]/66 quadruple semitendinosus/gracilis tendons [QSGT] patients) who underwent BPTB and QSGT surgery were functionally assessed.

Intervention: All patients were functionally assessed (knee extension/flexion isokinetic strength and knee joint laxity) at a mean follow-up time of 11 months.

Main outcome measurements: Laxity was measured utilizing the Kneelax arthrometer, whereas isokinetic strength of the knee extensor/flexor muscle groups was measured using the Biodex Multi Joint System 2 (180 degrees/s and 300 degrees/s).

Results: The QSGT group had significantly greater knee joint laxity when compared with the BPTB group (P < 0.001). Furthermore, females in the QSGT group demonstrated the greatest knee joint laxity overall (P < 0.001). Additionally, a significant flexor torque deficiency was demonstrated in the QSGT group (P < 0.001); however, no differences in extensor torque were observed.

Conclusions: The use of a BPTB autograft achieved better knee joint stability as well as greater knee flexor torque than the QSGT autograft. Both grafts exhibited a similar knee extensor torque deficit, indicating that only quadriceps strength is not graft-dependent.

Publication types

  • Clinical Trial
  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Anterior Cruciate Ligament / surgery*
  • Female
  • Humans
  • Joint Instability*
  • Knee Joint
  • Male
  • Middle Aged
  • Muscle Weakness
  • Muscle, Skeletal
  • Orthopedic Procedures / methods*
  • Plastic Surgery Procedures / methods
  • Range of Motion, Articular
  • Tendons / transplantation*
  • Treatment Outcome