Hi @revvy and welcome to Mayo Clinic Connect. You'll see that I moved your post here: Left hip pain and groin 3 years after posterior total hip replacement: https://connect.mayoclinic.org/discussion/left-hip-pain-and-groin-3-years-after-posterior-total-hip-replacement/ I did that so you can connect with other people having a difficult time like your husband.
You might also want to read this one: Total hip replacement: pain 15 months post-op: https://connect.mayoclinic.org/discussion/hip-pain-15-months-post-total-hip-arthroplasty/
Reference info: "Doctors at the Mayo Clinic writing in the Journal of bone and joint surgery suggest that a potential cause of persistent groin pain after total hip arthroplasty is impingement of the iliopsoas tendon. Treatment options include conservative management, tenotomy, and acetabular revision (surgery to adjust or replace the hip socket component)."

Have the sharp pains been present since his surgery?