You are in: eMedicine Specialties > Orthopedic Surgery > HAND AND UPPER EXTREMITY Scapholunate Advanced CollapseArticle Last Updated: Sep 2, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 13
  Author: Dimitrios Danikas, MD, Consulting Staff, Department of Surgery, Division of Plastic Surgery, Jersey Shore Medical Center, CentraState Medical Center, Riverview Medical Center, Monmouth Medical Center Dimitrios Danikas is a member of the following medical societies: American Academy of Anti-Aging Medicine, American College of Surgeons, and American Society of Plastic Surgeons Coauthor(s): Steve Lee, MD, Physician in Plastic, Reconstructive, and Hand Surgery, Plastic Surgery, PLLC; Michael Neumeister, MD, FRCSC, FACS, Program Director, Assistant Professor, Department of Surgery, Division of Plastic Surgery, Southern Illinois University School of Medicine; Richard Brown, MD, FACS, Clinical Professor, Department of Surgery, Division of Plastic and Reconstructive Surgery, Southern Illinois University School of Medicine Editors: A Lee Osterman, MD, Director of Hand Surgery Fellowship, Director, Philadelphia Hand Center; Director, Professor, Department of Orthopedic Surgery, Division of Hand Surgery, University Hospital, Thomas Jefferson University; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Michael Yaszemski, MD, PhD, Associate Professor, Departments of Orthopedic Surgery and Bioengineering, Mayo Foundation, Mayo Medical School; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Harris Gellman, MD, Consulting Surgeon, Broward Hand Center; Voluntary Clinical Professor of Orthopedic Surgery and Plastic Surgery, Departments of Orthopedic Surgery and Surgery, University of Miami School of Medicine Author and Editor Disclosure Synonyms and related keywords: scapholunate advanced collapse, SLAC wrist, degenerative arthritis, scaphoid injury, scapholunate collapse, scapholunate dissociation, wrist pain, carpal tunnel syndrome, carpal ligament instability, scaphoid fracture, wrist arthritis, arthritis of the wrist, wrist arthrodesis, periscaphoid arthritis, scaphoid nonunion advanced collapse, SNAC, Terry Thomas sign, carpal bone, scaphoid, lunate, hand bone, os lunatum, os scaphoideum, perilunate fracture dislocations, perilunate injuries INTRODUCTIONSection 2 of 13
  Scapholunate advanced collapse (SLAC) of the wrist is the most common pattern of degenerative arthritis in the wrist. Watson and Ballet coined the term SLAC wrist in 1984.1 Findings of bilateral SLAC wrist on a prehistoric skeleton from Hassi-el-Abiod site in Malian Sahara provide paleopathological evidence of the existence of this disease 7000 years ago. ProblemThe hallmark of scapholunate advanced collapse (SLAC) is scaphoid or scapholunate ligament injury with collapse on the radial side of the wrist. FrequencyScapholunate advanced collapse (SLAC) has been reported to be more common in men than in women and more common in persons who perform manual labor than in other individuals. It is most common in the dominant wrist. SLAC has been reported in people aged 19-82 years. The peak decade for corrective SLAC surgery is the fourth decade of life. The periscaphoid area is the site of 95% of all wrist degenerative diseases. The SLAC pattern is seen in 57% of patients with periscaphoid arthritis. EtiologyA scapholunate advanced collapse (SLAC) wrist pattern is the result of many radial-sided wrist pathologies (see Images 1 through 4 below, as well as Images 1 through 8 in the Multimedia Section). Most common is scapholunate dissociation with rotatory subluxation of the scaphoid. Scaphoid nonunion advanced collapse (SNAC) is another very common cause.2 Other etiologies include Preiser disease (avascular necrosis of the scaphoid),3 midcarpal instability, intra-articular fractures involving the radioscaphoid or capitate-lunate joints, Kienböck disease (see Image 2 below),4 primary degenerative arthritis with attenuation of the scapholunate ligament and scapholunate dissociation,5, 6 capitolunate degeneration, and inflammatory arthritis, such as seen in the crystalline deposition disorders of goutandcalciumpyrophosphatedihydratedepositiondisease(CPPD).7, 8 Initial treatment of the cause of the SLAC wrist (eg, scaphoid nonunion, scapholunate dissociation) may prevent subsequent degeneration.  Scapholunate advanced collapse (SLAC) wrist from nonunion of the scaphoid. The patient underwent 4-bone fusion. PathophysiologyThe distal radius has 2 articular fossae for the scaphoid and lunate. The scaphoid fossa is elliptical or ovoid. It narrows toward the radial styloid in a dorsal-volar plane. Thus, the scaphoid proximal articular surface is shaped like a spoon. The lunate fossa is spherical. Injury of the scaphoid or its supportive ligaments can cause radial-sided collapse with flexion of the scaphoid, thus resulting in incongruence of the radioscaphoid joint. Thus, narrowing of the radioscaphoid joint first begins at the radial styloid aspect (stage 1A). Radiographic changes appear as a sharp elongation on the radial styloid. As the disease progresses, the rest of the radioscaphoid joint is destroyed (stage 1B). In stage 1B, the entire scaphoid fossa is involved. Complete collapse of radioscaphoid joint alters the normal load-bearing ability of the capitolunate joint. This results in a radial or dorsal radial position of the capitate. Shear stress destroys cartilage in the capitolunate joint leading to the most advanced stage, midcarpal scapholunate advanced collapse (SLAC) (stage 2). In stage 2, the capitolunate joint is additionally narrowed and sclerotic. As the arthritic pattern thus progresses, it shifts from the scaphoid fossa of the radius to the midcarpal capitate articulation. At all stages of SLAC wrist, the radiolunate joint is not involved because of its spherical shape. The lunate is congruently loaded in every position and, thus, highly resistant to degenerative changes. This sparing of the lunate fossa provides a basis for some of the motion-preserving procedures to treat SLAC wrist. Long-standing and untreated SLAC wrist can lead to a painful wrist at rest and during use, deterioration of range of motion (ROM), and decreased grip strength. The radiographic SLAC appearance does not always correlate with the patient's symptoms. ClinicalA history of wrist injury, scaphoid fracture, carpal tunnel decompression, or carpal ganglion excision may be present. Many patients with scapholunate advanced collapse (SLAC) wrist have minimal symptoms and may present because of a secondary problem, such as carpal tunnel syndrome. Patients may have a variable duration history of wrist pain during activity. Patients relate their symptoms to increased activity and overuse. Postactivity pain may be present. Patients may have modified their activities, depending on the severity of symptoms. Many patients have used nonsteroidal anti-inflammatory drugs (NSAIDs) for pain relief. Wrist edema may be present, and patients may have pain with motion, especially when loading the wrist in an extended position. Limited wrist ROM is typical, and an average wrist flexion/extension arc of 80-90° has been reported. Direct palpation of the scapholunate joint or radiocarpal joint generally elicits pain. Pain with resistance against active finger extension while the wrist is held in passive flexion is common. A scaphoid shift test also elicits pain. To perform this maneuver, the examiner places the fingers of the same hand on the dorsum of the distal radius of the wrist being examined (ie, the left hand is used to examine left wrist). The examiner's thumb is placed volarly on the scaphoid tuberosity and pushed dorsally while passively radially and ulnarly deviating the patient's wrist with the other hand. This stresses the periscaphoid ligaments and subluxes the scaphoid dorsally, thus eliciting pain if periscaphoid disease is present. Differential clinical diagnoses of SLAC wrist arthritis include essentially any condition that causes dorsal radial wrist pain. Common differential diagnoses include scaphoid fractures, de Quervain tenosynovitis, scapholunate dissociation, Kienböck disease, distal radial fracture, Preiser disease, and scaphotrapezoid-trapezial (STT) joint arthritis. INDICATIONSSection 3 of 13
Asymptomatic scapholunate advanced collapse (SLAC) wrist generally does not require treatment, although some patients may require surgery for secondary problems, such as carpal tunnel syndrome. Mild symptomatic SLAC can often be managed nonoperatively. For more symptomatic SLAC, operative intervention is warranted. The surgical procedure is planned based on radiographic findings, symptoms, physical examination findings, and the surgeon's preference. Since more motion occurs at the radiocarpal joint than the midcarpal joint, and since the radiolunate joint is generally spared, a limited wrist fusion with scaphoid excision is an option, although a total wrist fusion is often more predictable in alleviating pain. In stage 1 SLAC with sparing of the capitolunate joint, a proximal row carpectomy (PRC) may also be used to preserve partial wrist motion. RELEVANT ANATOMYSection 4 of 13
See Surgical therapy. CONTRAINDICATIONSSection 5 of 13
See Surgical therapy. WORKUPSection 6 of 13
Imaging Studies
Diagnostic Procedures
StagingSee Pathophysiology. TREATMENTSection 7 of 13
Medical therapyIt is not uncommon to encounter a patient with an asymptomatic scapholunate advanced collapse (SLAC) wrist.10 The patient should be informed of the problem but may not require any treatment. If symptomatic, the patient should be given the various options for treatment. Mild symptomatic SLAC can often be managed nonoperatively with periodic steroid injections, splinting, and NSAIDs. If the grip strength registers more than 80% that of the uninvolved wrist and the condition is not significantly impairing, then living with the condition is a valid option.11 Surgical therapyLimited wrist fusion (SLAC reconstruction) A scapholunate advanced collapse (SLAC) reconstruction involves scaphoid excision and arthrodesis of the capitate, lunate, hamate, and triquetrum.12 Two parallel dorsal transverse incisions, a lazy S, or a central longitudinal incision over the distal radiocarpal joint and styloid process is made. The extensor retinaculum is incised through the third dorsal compartment. The terminal branch of the posterior interosseous nerve in the floor of the fourth extensor compartment can be sacrificed as an adjunctive pain relief measure. The wrist capsule is opened over the capitolunate joint. The scaphoid is resected in piecemeal fashion. Articular cartilage and subchondral bone are removed from the capitate, lunate, hamate, and triquetrum. Care should be taken to maintain the anatomic relationship of the intercarpal intervals. Cancellous bone is harvested from the distal radius, the proximal ulna or, from the iliac crest. Lunate dorsal intercalated segment instability (DISI) should be corrected, and 5 percutaneous Kirschner wires (K-wires) are used. Two wires are placed through the capitate into the lunate, one each through the hamate and triquetrum into the lunate, and a fifth wire through the triquetrum into capitate. Cancellous bone graft is packed between the interstices of the 4 bones. A long arm splint is placed after the procedure. After a week, the splint is replaced with a long arm cast, which is maintained for 3 weeks. Then, a short arm cast is placed and maintained for an additional 2-4 weeks. The cast and wires are removed when fusion is evident on radiographs. Some newer fixation methods of this 4-quadrant fusion include the use of intercalary screws and a dorsal carpal plate marketed especially for this fusion. It remains to be seen whether the increased cost of such devices results in improved outcomes. More solid fixation does allow the use of a short arm cast and an earlier initiation of wrist ROM therapy.13 Patients with radiolunate changes are not candidates for SLAC reconstruction. A wrist arthrodesis should be performed. Proximal row carpectomy Proximal row carpectomy (PRC) requires resection of the proximal row of wrist bones to allow articulation of the capitate within the lunate fossa.14 15 For a successful procedure, both the proximal capitate articular surface and the lunate fossa should ideally be free of pathology. The procedure is usually effective only when the disease is restricted to the radioscaphoid joint. PRC provides the best motion (average arc 71°) but may be associated with painful narrowing of radiocapitate joint. It is not indicated for stage 2 SLAC wrist. It may serve as a salvage procedure for stages 1A and 1B when limited wrist fusion is not indicated. Failure of PRC requires conversion to wrist arthrodesis. A dorsal longitudinal or transverse incision is used. The extensor tendons are retracted. A longitudinal capsulotomy is extended radially and ulnarly. The capitate is identified, and its articular surface is inspected. In the presence of capitate degenerative changes, the procedure should not be performed. If both proximal capitate articular surface and lunate fossa are free of pathology, the scaphoid, lunate, and triquetrum are excised. Both radioscaphocapitate and long radiolunate ligaments are preserved. Wrist collapse follows, with placement of the capitate head in the lunate fossa along with radial deviation of the wrist. If impingement between the radial styloid and the trapezium is present, a limited radial styloidectomy is performed. The capsulotomy incision is closed snugly. Following the procedure, the wrist is splinted for 4 weeks. Early active digital flexion and extension are recommended. ROM exercises start 4 weeks after the procedure. Strengthening exercises and heavy lifting may begin 3 months after the procedure.
Total wrist fusion diminishes pain, but wrist function is sacrificed. Patients may have functional limitations interfering with lifestyle, and total fusion does not always result in complete pain relief. Using a central, dorsal, longitudinal incision, the extensor retinaculum is incised. The incision is carried down to bone surface from middle finger metacarpal to distal radius, raising capsular and periosteal flaps. Articular cartilage and subchondral bone are resected from the radioscaphoid, radiolunate, lunocapitate, scaphocapitate, and middle finger carpometacarpal joints. The radioulnar joint should not be entered. The index finger carpometacarpal joint may also be opened for fusion. The radial metaphysis is generally used for the necessary cancellous bone graft and more distal harvest is not required. Bone grafts are placed in the radiocarpal, midcarpal, and carpometacarpal fusion sites, and a wrist fusion plate is applied.19 The fusion plate is secured with screws at the middle finger metacarpal, the capitate, and the radius. Periosteal and capsular flaps are reapproximated. A short arm splint is applied until fusion can be seen on radiographs. Fusion is usually evident in 6-8 weeks.20, 21 Total wrist arthroplasty Total wrist arthroplasty is an alternative to diffuse arthrosis of the wrist, especially in rheumatoid arthritis and if bilateral disease is present.22 With bilateral disease, a combination of a total wrist arthroplasty and a contralateral total wrist fusion is an option. Numerous implants have been used; however, major complications of implant loosening and wear of the components are common. Follow-upFor excellent patient education resources, visit eMedicine's Arthritis Center. Also, see eMedicine's patient education articles Carpal Tunnel Syndrome. COMPLICATIONSSection 8 of 13
OUTCOME AND PROGNOSISSection 9 of 13
SLAC reconstruction In a series of 250 procedures, Watson and Weinzweig reported nonunion in 1%, wound infection in 1%, reflex sympathetic dystrophy in 1.5%, and capitate-radial impingement requiring revision arthroplasty in 13%.23 The high incidence of dorsal impingement was the result of noncorrection of the lunate dorsal intercalated segment instability (DISI) deformity. A flexion/extension arc of 60-65° can be expected with a 4-bone fusion. Brown and Erdmann present complications after 50 consecutive limited wrist fusions.24 Proximal row carpectomy Krakauer et al compared scapholunate advanced collapse (SLAC) reconstruction with proximal row carpectomy (PRC).25 Patients with PRC had 71° of motion, and patients with SLAC reconstruction had 54° of motion. Krakauer et al recommend PRC for patients without lunate pathology and SLAC reconstruction for patients with capitolunate arthritis. Wyrick et al presented similar results and recommendations.26 Total wrist motion was 85° and grip strength 94% in the PRC group. Total wrist motion was 67° and grip strength 74% in the SLAC group. Imbriglia et al presented results of long-term follow-up after proximal-row carpectomy.27 Four years after the procedure, 26 of 27 patients had pain relief, ROM did not deteriorate, and 80% of patients improved their grip strength. PRC appears to offers better ROM and almost normal grip strength. In some patients, conversion to wrist arthrodesis may be required because severe pain persists. Total wrist arthrodesis Hastings et al reported a 2% nonunion rate with total wrist fusion.28 The most common nonunion site was the middle finger carpometaphalangeal joint. To prevent this complication, complete decortication of the dorsal 80% of the carpometaphalangeal joint is recommended. Other complications were tendon adhesions (in 3.5% of patients), carpal tunnel syndrome, and iliac crest harvest site problems (in 1.7% of patients). Weiss et al discuss upper extremity function after arthrodesis.29 Dacho et al discuss long-term results.30 Total wrist arthroplasty Major complications of implant loosening and wear of the components are common. FURTHER READINGSection 10 of 13
Forearm, wrist, & hand (acute & chronic), not including carpal tunnel syndrome. Work Loss Data Institute. 2004 (revised 2007 May 16). 80 pages. [NGC Update Pending] NGC:005799 ACKNOWLEDGMENTSSection 11 of 13
The authors and editors gratefully acknowledge the contributions to this topic made by Mark F. Hendrickson, M.D. MULTIMEDIASection 12 of 13
REFERENCESSection 13 of 13
Scapholunate Advanced Collapse excerpt Article Last Updated: Sep 2, 2008 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
