Evidence / Sources / E14
Ebert JR et al. Isokinetic knee extensor strength deficit following MACI. Clin Biomech 2012
Evidence strength 2 of 5
Cross-sectional isokinetic study · n = 60 · 5 yr follow-upMACI ITSELFFull text →What it can tell you
That quadriceps deficits persist five years after ACI, are specific to the extensors, and hide at 45° of flexion where peak-torque testing misses them. The authors' conclusion — early rehab is not sufficient to restore long-term strength — is this site's thesis.
What it cannot
Trajectory. Cross-sectional design, no pre-operative baseline, so it shows where a cohort sat at five years, not how anyone got there or whether training changes it.
Everything on this site that leans on E14 — 33 claims
Stage I · Before [patellofemoral]“A formal strength and function baseline recorded before surgery. Every post-operative symmetry measure compares against the other leg — which will also detrain. A pre-operative mea…”Stage I · Before [tibiofemoral]“A formal strength and function baseline recorded before surgery. Every post-operative symmetry measure compares against the other leg — which will also detrain. A pre-operative mea…”Stage I · Before · Questions“Can I get a formal strength and function baseline recorded before surgery — both legs, documented numbers?”Stage IV · Strength“By month three the studied protocols have restored full weight and near-full motion; what remains is the quadriceps, and it matters more than it feels like it should. Post-operativ…”Stage IV · Strength · Questions“When will my quadriceps strength actually be measured — and against what reference?”Stage VI · Long horizon“At five years post-implantation, knee extensor torque at 45° of flexion was significantly reduced at every speed tested — a deficit peak-torque testing misses. The study's authors …”Stage VI · Long horizon [tibiofemoral]“A yearly strength check against an absolute reference, not just the other leg — symmetry can overestimate function because the uninvolved limb detrains too, a limitation the cohort…”Stage VI · Long horizon · Questions“Now that formal rehab is ending — can we set a standing annual review with strength actually measured, not just symptoms asked about?”Program · Stage IV (patellofemoral)“Single-leg work through the permitted arc — Symmetry against the other leg flatters both — the uninvolved leg detrains too.”Program · Stage IV (patellofemoral)“Get your strength measured, not guessed — Not an exercise — an appointment. The five-year deficit data is the reason this row is here.”Program · Stage IV (patellofemoral) · Gates“Measured quadriceps progress against a fixed reference, not just the other leg”Program · Stage IV (tibiofemoral)“Single-leg work under building load — Symmetry against the other leg flatters both — the uninvolved leg detrains too.”Program · Stage IV (tibiofemoral)“Get your strength measured, not guessed — Not an exercise — an appointment. The five-year deficit data is the reason this row is here.”Program · Stage IV (tibiofemoral) · Gates“Measured quadriceps progress against a fixed reference, not just the other leg”Program · Stage VI (patellofemoral)“Extensor strength work, indefinitely — Association, not causation — a Level IV series cannot say whether strong quads protect knees or good knees permit strong quads. It is still t…”Program · Stage VI (patellofemoral)“Annual strength review, against a fixed reference — The randomized cohort that stayed durable held limb symmetry near 100% for a decade — and its authors still cautioned that symme…”Program · Stage VI (patellofemoral) · Gates“A yearly strength check against an absolute reference, not just the other leg”Program · Stage VI (tibiofemoral)“Extensor strength work, indefinitely — Association, not causation — a Level IV series cannot say whether strong quads protect knees or good knees permit strong quads. It is still t…”Program · Stage VI (tibiofemoral)“Annual strength review, against a fixed reference — The ten-year randomized cohort is femoral condyle — the one place the benchmark population matches a tibiofemoral reader exactly…”Program · Stage VI (tibiofemoral) · Gates“A yearly strength check against an absolute reference, not just the other leg”Exercise Library · Straight-leg raise, no lag · Evidence for this movement“That the quadriceps deficit is worth this much of the stage — measurable at five years; tracks with ten-year quality of life”Exercise Library · Single-leg work“Knee extensor deficits were still measurable five years after the operation, and the authors reporting limb symmetry values cautioned that symmetry can overestimate knee function.”Exercise Library · Strength measurement“Knee extensor torque at forty-five degrees of flexion was significantly reduced at all test speeds five years after the operation, while peak torque differences did not reach signi…”Exercise Library · Heavy strength work, continued“The randomized cohort that maintained its outcomes to ten years held limb symmetry near parity across extensor, flexor and hop testing, and its authors concluded that early supervi…”Exercise Library · Maintenance strength“The authors who found extensor deficits persisting five years after the operation concluded that the early supervised rehabilitation phase is not sufficient to restore long-term kn…”Exercise Library · Annual strength review“Angle-specific extensor deficits were still measurable five years after the operation, and the randomized cohort that maintained its outcomes to ten years held limb symmetry near p…”Benchmarks · isokinetic-strength knee extensor @45° flexion“reduced at all speeds (P < .05) at 5 years — Cross-sectional isokinetic testing after ACI”What we don't know · № 10“The strength cut-offs in use were validated in ligament reconstruction, and limb symmetry can overestimate function.”Why this · Why the quadriceps gets the priority, and why a lagging raise ends the set“Knee extensor deficits were still measurable five years after implantation, concentrated at around 45° of flexion, and greater quadriceps strength tracked with better ten-year knee…”Why this · Why the strength gets measured here rather than estimated“Knee extensor torque was significantly reduced at every test speed five years after implantation, concentrated at around 45° of flexion — an angle-specific deficit that a leg can h…”Why this · Why the strength gets measured, and why work comes back by demand rather than by date“Knee extensor torque was significantly reduced at every test speed five years after implantation, concentrated at around 45° of flexion, and greater post-operative quadriceps stren…”Why this · Why a yearly measurement against a fixed reference“Angle-specific extensor deficits were still measurable five years after the operation, and greater quadriceps strength travelled with better ten-year knee-related quality of life.”Why this · Why a yearly measurement against a fixed reference“The randomized cohort that held its outcomes to ten years also held limb symmetry near parity across every strength and hop measure — and angle-specific extensor deficits were stil…”
Read it like a sceptic
n=60, mixed lesion locations, 2012 rehabilitation practices — protocols have shifted since.
Population
ACI, knee
Selection policy
Sources enter the registry through docs/research — the evidence table records design, population, and size for every entry, and pages cannot cite anything outside it.