Transcriptional profiling and muscle cross-section analysis reveal signs of ischemia reperfusion injury following total knee arthroplasty with tourniquet

Abstract

Total knee arthroplasty (TKA) is the most common and cost‐effective treatment for older adults with long‐standing osteoarthritis. Projections indicate that nearly 3.5 million older adults will undergo this procedure annually by the year 2030. Thus, understanding the factors that lead to optimal outcomes is of great clinical interest. In the majority of cases, tourniquet is applied during surgery to maintain a clear surgical field, however, there is debate as to whether this intervention is completely benign. In particular, muscle atrophy is a significant factor in preventing full functional recovery following surgery, and some evidence suggests that tourniquet application and the associated ischemia–reperfusion injury that results contributes to muscle atrophy. For this reason, we examined tissue level changes in muscle in TKA patients following surgery and found that there was a significant increase in cross‐sectional area of muscle fibers of all types. Furthermore, to detect changes not evident at the tissue level, we performed NextSeq analysis to assess the transcriptional landscape of quadriceps muscle cells following TKA with tourniquet and found 72 genes that were significantly upregulated. A large proportion of those genes regulate cell stress pathways, suggesting that muscle cells in our cohort of older adults were capable of mounting a significant response to cell stress. Furthermore, factors related to complement were upregulated, suggesting tourniquet may play a role in priming cells to ischemia reperfusion injury. Therefore, our analysis reveals potential harms of tourniquet during TKA, thus suggesting that surgeons should consider limiting its use.

Tourniquet Use During Knee Replacement Surgery May Contribute to Muscle Atrophy in Older Adults

“…Moreover, Akt and JNK interact with FOXO3a, and are regulated by inflammatory cytokines CXCL2, CXCL1, and CCL2, which we show in our transcriptional profiling, are upregulated. As well, MuRF1, a key regulator of the proteasomal pathway, is regulated by NFkB (and by FOXO3a), which is regulated by several molecules in our dataset including NFKBIZ, CYR61, KDM6B, MT1M, TNFRSF1A, HES1, and BCL3 (33). Therefore, our gene expression analysis shows that TKA with tourniquet induces expression of the molecular components of muscle atrophy.…”

“…The clinical view that tourniquet use is benign in older adults having TKA must be reevaluated in light of our recent data showing reductions in anabolic signaling (37) and up regulation of the catabolic FOXO (1) and UPR (14) pathways that precede, by a few hours, muscle cell swelling and gene clusters associated with cell stress (33). Muscle atrophy after TKA occurs at a rate of 1% per day (14% loss over 2 weeks), and slows significantly between 2 and 6 weeks post-TKA (i.e., −14% loss at 2 weeks vs. −18% at 6 weeks) (9).…”

“…Second, the accumulation of cytosolic Ca 2+ causes an inward flux into the mitochondrial matrix, which is a potential mechanism for initiating mitochondrial-mediated apoptosis, potentially via the mitochondrial permeability transition pore (mPTP). Either way, muscle swelling occurs about 2.3 hours after TKA (33), and we were able to measure an increase in cross-sectional area of all three fiber types (Type I, IIa, and IIx) (Figure 5). …”

“…To gain a better understanding of the changes in skeletal muscle occurring during and after TKA at the molecular and cellular levels, our research group has collected muscle biopsy samples in the operating room (OR) before tourniquet inflation (baseline), during maximal ischemia, and during reperfusion, usually within 10 to 25 minutes. Our most recent data (33) examines changes in cell size and gene expression profiles from muscle samples collected about 2.3 hours post-TKA.…”

“…Therefore, PIM-1 is clearly a critical “node” in the gene regulatory network controlling cell stress response. From a clinical standpoint, this is an important observation because it suggests that older individuals retain the capacity to mount a significant cellular defense response following TKA and tourniquet application (33). …”