Oh yes, knee reconstruction is so very much more complex (and has so many different types of injuries) than an Achilles tendon repair. Orthopaedic surgeons are always trying to improve procedures and outcomes in the knees, and they are still chasing the holy grail of finding ways to develop a reliable and cost-effective means of regenerating the knees articular cartilage.
Let's go the other way- I know two two that don't. Running backs, and Linebackers. Especially Linebackers, as I show below. Others are probably comparable to each other in both returning rate and performance level attained.
I'm not counting on an August return, and if he does, it will likely be with a notable reduction in performance.
**In a new fairly recent study (Oct. 2017), they found almost 73% of players returned to the NFL after Achilles tendon repair (recently published study in Foot and Ankle International).**
“Achilles tendon injuries in the NFL are common season-ending injuries that require a surgical repair,” Joshua D. Harris, MD, told Healio.com/Orthopedics. “Our recent study of 95 NFL players showed that it was also a career-ending injury in nearly 28% of those analyzed. Although postoperative performance was worse in running backs and (especially) linebackers vs. pre-injury. Results showed that at a mean of 339.8 days after surgery, 71 NFL players were able to return to sport, 24 did not."
The reports of an August return was Kansas City GM Brett Veach painting a rosy picture-
"K.C. Chiefs general manager Brett Veach says left tackle Eric Fisher is expected back by mid-August."
In this article-
It also said in the article-
Here is the Veach proclamation,
“I think with that injury with the time leading up for the season, Rick has here a mid-August return. You know how that works, that’s always to be determined until the player actually reports back to camp and goes through the offseason to see where he is.”
10 days later, he releases both Eric Fisher and Mitch Schwartz. So does he have confidence in that August date now?
The latest study data above shows an average 340 days for (well, for 73% of them) a player to return to play. Fisher was hurt Jan 29, 2021. A mid August return would place Fisher’s recovery timeline at approximately 225 days, or seven and a half months. 115 days ahead of the mean return time frame.
You believe what you want, but I know which side of the timeline scale I'm looking at.