The very nature of cruciate ligament repairs makes it extraordinarily difficult for any player to overcome successive injuries to the same joint.
Bear in mind that in the lead up to Paul Gascoigne's injury in the 1991 FA Cup Final and subsequent semi-experimental ACL treatment (via Hans-Wilhelm Müller-Wohlfahrt, I think) a cruciate rupture was a career ending certainty.
Brian Clough, who was an extraordinarily lethal striker before he became arguably the greatest football manager this country has produced, is one of the most noteworthy victims of a ruptured cruciate.
Treatments have moved on significantly since Gascoigne's semi-successful ligament graft. But even cutting edge medicine still cannot return a badly damaged knee ligament to a hundred percent of its former functionality. Whilst the load strength of the new grafts are now superior to the original ligament - joint flexibility and elasticity is still an issue.
I figured Johnny's footwork might take a bit of a hit after his first injury and after watching his return he indeed seemed heavy footed and less able to change direction quickly. My guess is a second injury will degrade his performance less cumulatively than exponentially.
I hope I'm wrong because Lomax is a damned good player when fit.
