Patellofemoral joint stress during weight-bearing and non-weight-bearing quadriceps exercises

Patellofemoral Osteoarthritis: Are We Missing an Important Source of Symptoms After Anterior Cruciate Ligament Reconstruction?

Anterior cruciate ligament (ACL) rupture is a well-established risk factor for knee osteoarthritis (OA). Fifty to ninety percent of individuals will develop radiographic tibiofemoral OA within a decade after ACL injury and anterior cruciate ligament reconstruction (ACLR). Although less well recognized, radiographic patellofemoral OA is present in approximately 50% of individuals at more than 10 years after ACLR. This early-onset OA and its associated pain and functional limitations pose a particular challenge to younger adults with OA compared to an older OA population. Targeted interventions need to be developed to reduce the burden of early-onset OA following ACLR. Emerging evidence suggests that such interventions should target both the patellofemoral and tibiofemoral joints.

Forward lunge knee biomechanics before and after partial meniscectomy

BACKGROUND

Patients following meniscectomy are at increased risk of developing knee osteoarthritis in the tibiofemoral compartment and at the patellofemoral joint. As osteoarthritis is widely considered a mechanical disease, it is important to understand the potential effect of arthroscopic partial meniscectomy (APM) on knee joint mechanics. The purpose of this study was to evaluate changes in knee joint biomechanics during a forward lunge in patients with a suspected degenerative meniscal tear from before to three months after APM.

METHODS

Twenty-two patients (35-55 years old) with a suspected degenerative medial meniscal tear participated in this study. Three dimensional knee biomechanics were assessed on the injured and contralateral leg before and three months after APM. The visual analogue scale was used to assess knee pain and the Knee Injury Osteoarthritis Outcome Score was used to assess sport/recreation function and knee-related confidence before and after APM.

RESULTS

The external peak knee flexion moment reduced in the APM leg compared to the contralateral leg (mean difference (95% CI)) -1.08 (-1.80 to -0.35) (Nm/(BW × HT)%), p = 0.004. Peak knee flexion angle also reduced in the APM leg compared to the contralateral leg -3.94 (-6.27 to -1.60) degrees, p = 0.001. There was no change in knee pain between the APM leg and contralateral leg (p=0.118). Self-reported sport/recreation function improved (p = 0.004).

CONCLUSIONS

Although patients self-reported less difficulty during strenuous tasks following APM, patients used less knee flexion, a strategy that may limit excessive patellar loads during forward lunge in the recently operated leg.