- scapholunate advanced collapse (SLAC) refers to a specific pattern of osteoarthritis and subluxation which results from untreated chronic scapholunate dissociation
or from chronic scaphoid non-union
- degenerative changes occur most often in areas of abnormal loading;
- radial-scaphoid joint is involved initially, followed by degeneration in the unstable lunatocapitate joint, as capitate subluxates dorsally on lunate;
- radioscaphoid joint is first to develop degenerative changes;
- capitolunate & STT joints, follow in order w/ degenerative changes;
- capitate migrates proximally into space created by scapholunate dissociation;
- radiolunate joint is usually spared because of concentric articulation of lunate w/ in speroid lunate fossa of distal radius;
- w/ end stage SLAC midcarpal joint collapses under compression & lunate assuming an extended or dorsiflexed position (DISI deformity
- proximal row carpectomy
- advantages are that it is technically easy, and often allows better preservation of strength and motion, as compared to limited carpal arthrodesis;
- patients can expect over 60% of normal ROM as compared to opposite wrist and over 90% of normal grip strength;
- this compares to four corner fusion, in which patients can expect less than 50% ROM and about 75% grip strength;
- relatively contra-indicated w/ capitolunate arthrosis;
- wrist fusion
- limited carpal fusion: (LCF);
- 4 corner fusion
- involves preservation of radiolunate joint and stabilization of the midcarpal row;
- usually LCF is combined w/ scaphoid excision inorder to adress radioscaphoid arthrosis;
- incomplete reduction of the dorsiflexed lunate may result in limitation of wrist extension;
- may be indicated for wrists w/ more extensive intercarpal arthrosis;
- in the report by Cohen MS, et al
, 2 cohort populations of 19 patients from separate institutions performing exclusively either a scaphoid excision and 4-corner arthrodesis (lunate, capitate, hamate, and triquetrum) or proximal row carpectomy (PRC) for scapholunate advanced collapse arthritis were compared.
- length of the follow-up period averaged 28 months for the 4-corner arthrodesis group compared with 19 months for the PRC patients;
- at the follow-up examination wrist motion revealed no significant differences in the flexion-extension arc, averaging 81° in the PRC patients and 80° following 4-corner arthrodesis, which was 62% and 58%, respectively, of the opposite wrist.
- 4-corner arthrodesis patients maintained greater radial deviation and total percent radial-ulnar deviation of the wrist;
- grip strength averaged 71% for the PRC group compared with 79% for the 4-corner arthrodesis patients.
- pain relief was similar using a variety of measures and patient satisfaction was equivalent.
- both PRC and scaphoid excision and 4-corner arthrodesis are motion-preserving options for the treatment of scapholunate advanced collapse arthritis with minimal subjective or objective differences in short-term follow-up evaluations.
- ref: Degenerative arthritis of the wrist: proximal row carpectomy versus scaphoid excision and four-corner arthrodesis
Scapholunate advanced collapse wrist salvage
Surgical treatment of scapholunate advanced collapse
Asymptomatic SLAC wrist: does it exist?
Scapholunate advanced collapse wrist: proximal row carpectomy or limited wrist arthrodesis with scaphoid excision
Motion preserving procedures in the treatment of scapholunate advanced collapse wrist: proximal row carpectomy versus four corner arthrodesis