The second row missed last Saturday's bonus point defeat against Racing Metro in Le Mans after suffering the injury during the home fixture against the Parisians the previous weekend.
Medical Performance Manager, Chris Towers, confirmed:
"Following consultation it was decided that surgery was the treatment of choice for Lloyd given the nature of his injury.
"He's had his operation, which went well, and it is anticipated that he'll be out of action for around four months while he recovers and rehabs from the injury."
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