A sling suspension system for supporting the thumb of a patient after basal joint arthroplasty, the sling suspension system comprising: an index metacarpal anchor, a thumb metacarpal anchor and a sling for securing the thumb metacarpal anchor to the index metacarpal anchor; the index metacarpal anchor comprising at least one bone-engaging element for engaging the index metacarpal and a sling-engaging element for capturing the sling to the index metacarpal anchor; the thumb metacarpal anchor comprising at least one bone-engaging element for engaging the thumb metacarpal and a sling-engaging element for capturing the sling to the thumb metacarpal anchor; and the sling comprising an elongated body having a first anchor-engaging element for securing the sling to the sling-engaging element of the index metacarpal anchor, and a second anchor-engaging element for securing the sling to the sling-engaging element of the thumb metacarpal anchor, wherein the second anchor-engaging element is adjustable.