Prolonged Alterations In Hindlimb Emg Following Acl Transection In An Experimental Model Of Osteoarthritis
Bibliographic record
Abstract
Alterations in knee joint loading and hind limb kinematics following anterior cruciate ligament transection (ACLT) have been associated with the onset of osteoarthritis (OA) through a reduction in joint loads. Knee joint loads have been directly measured nine days following ACLT, and subsequent changes in joint kinematics have been documented over the span of one year. However, the magnitude and duration of muscle activation adaptations in the hindlimb remain unknown following ACLT. PURPOSE: To quantify long-term changes in cat hindlimb muscle activation patterns following ACLT. METHODS: In this pilot study, indwelling bipolar electromyographic (EMG) electrodes were surgically implanted in four synergist muscle pairs on the cat hindlimb: rectus femoris (RF) and vastus lateralis (VL); semitendonosis (ST) and semimembranosus (SM); extensor digitorum longus (EDL) and tibialis anterior (TA); and medial gastrocnemius (MG) and soleus (SOL). EMG and high speed video data were recorded during level treadmill walking before ACLT and at 1, 2, 3, 4, and 6 weeks, and at 2, 6, 8, and 9 months following ACLT. RESULTS: Following ACLT, there was a reduction in mean EMG activation of the VL during stance, with an immediate increase in mean EMG amplitude in the RF during swing phase only. Both the SM and ST increased activity during stance phase for nine months after ACLT. Following ACLT, the EDL exhibited an extra burst of activity just prior to, or at paw strike in addition to the increased activity at paw off. Activity in the MG also increased during stance up to nine months, and the onset of muscle activation occurred earlier following ACLT for the SOL and MG. CONCLUSION: Following ACLT the knee flexor and extensor muscles demonstrate compensatory activation patterns that may stiffen the hindlimb, and predispose the knee joint to increased loads. The two-joint EDL muscle is recruited at paw strike following ACLT, suggesting that this muscle may function to assist in stabilizing the ACL deficient joint as a knee extensor in co-contraction with the hamstring muscles. Furthermore, long term increases in activation of the dorsiflexor and plantarflexor muscles during stance may further contribute to increasing joint loads leading to OA.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".