SLAC மற்றும் SNAC கை தகவல்

This is the clinical evidence summary written for health professionals. It is technical, and it lists the research this page was built from. You do not need to read it to understand your treatment or to make a decision about it.

Overview

• Both proximal row carpectomy and four-corner fusion provide improvements in pain and subjective outcome measures for patients with symptomatic and appropriately staged SLAC or SNAC wrists [1].
• Midcarpal arthrodesis is a reliable procedure for treating SLAC- and SNAC-wrists in stages II and III [2].
• Midcarpal arthrodesis preserves some range of motion in the treatment of SLAC- and SNAC-wrists [2].
• Scaphoid excision and four-corner fusion is indicated for the treatment of the SLAC/SNAC wrist when significant pain is refractory to nonoperative measures [3].
• Limited carpal fusion is favored over proximal row carpectomy for patients treated for SNAC and SLAC wrist conditions, except for flexion-extension and grip strength in women [4].
• Bone density is greater at the capitolunate joint, the radial styloid, and the radiolunate joint in SNAC wrists compared to controls [6].
• Successful scaphoid reconstruction in SNAC wrists shifts the load back onto the proximal pole [10].
• Successful scaphoid reconstruction in SNAC wrists interrupts the otherwise inevitable degenerative pattern in scaphoid nonunions [10].
• Arthroscopic wrist debridement and radial styloidectomy is indicated for SLAC II or SLAC III wrists as an intermediate step to relieve pain and preserve functional motion [12].
• Scaphoidectomy and capsulodesis is mostly indicated as a palliative procedure in elderly patients with posttraumatic SNAC or SLAC wrist with limited functional demands [17].
• Arthroscopic wrist debridement and radial styloidectomy may have advantages in relieving pain while preserving wrist motion for SLAC stage 2 or 3 disease [20].
• Proximal row carpectomy is preferred for SLAC wrists with preserved capitate head cartilage due to socio-economic benefits, lower complication rates, and procedural ease [25].
• Arthroscopic resection arthroplasty of the radial column (ARARC) may be a viable surgical option for patients with SLAC wrist who desire a minimally invasive procedure [28].

Anatomy & Pathophysiology

• SNAC wrists exhibit a distinct pathomechanism of carpal instability characterized by a decreased sagittal lunotriquetral angle compared to SLAC wrists [5].
• Carpal malalignment in SLAC wrists affects the radio- and midcarpal joints and extends to the third carpometacarpal joint, with malalignment evident in both the sagittal and coronal planes [14].
• Radiographic classification of SLAC wrist has moderate reliability and reproducibility [7].
• Radiographic classification of SNAC wrist has limited reliability [7].
• Staging systems for SNAC wrist lack agreement [11].
• The Watson and Ballet classification of SLAC wrist osteoarthritis is widely accepted, simple, and a well-recognized guide to treatment despite significant limitations [18].
• Patients with SLAC wrist are more likely to be male and have a history of trauma compared to patients with first CMC OA [9].
• There is currently no scientific evidence that a scapholunate ligament injury visualized arthroscopically, without static x-ray changes, inevitably leads to SLAC wrist [13].

Classification

• The diagnosis of SLAC wrist should be reserved for patients in whom a traumatic disruption of the proximal carpal row has initiated the defined sequence of arthritic change outlined by Watson and Ballet [8].
• Patients with SLAC wrist are more likely to be male and have a history of trauma compared to patients with first carpometacarpal (CMC) osteoarthritis [9].
• Classification of SNAC wrist has limited reliability [7].
• SNAC wrists differ from SLAC wrists by exhibiting a decreased sagittal lunotriquetral angle, indicating a distinct pathomechanism of carpal instability [5].
• Distal row pronation and translation and radiolunate arthritis are demonstrated in SNAC wrists via quantitative 3-D CT [6].
• Scaphotrapeziotrapezoid (SOAC) joint osteoarthritis is differentiated from SLAC wrist, with the SOAC staging system guiding treatment decisions [15].

Clinical Presentation

• SLAC and SNAC wrists are characterized by symptomatic arthritis requiring intervention when pain is refractory to nonoperative measures [3].
• SNAC wrists differ from SLAC wrists in exhibiting a decreased sagittal lunotriquetral angle, indicating a distinct pathomechanism of carpal instability [5].

Investigations

• SNAC wrists exhibit a decreased sagittal lunotriquetral angle, indicating a distinct pathomechanism of carpal instability compared to SLAC wrists [5].
• The diagnosis of SLAC should be reserved for patients in whom a traumatic disruption of the proximal carpal row has initiated the defined sequence of arthritic change outlined by Watson and Ballet [8].
• Patients with SLAC wrist were more likely to be male and have a history of trauma compared to patients with first CMC OA [9].
• SOAC staging system can guide treatment decisions and differentiates SOAC from SLAC wrist [15].

Treatment

• Proximal row carpectomy provides improvements in pain and subjective outcome measures for patients with symptomatic and appropriately staged SLAC or SNAC wrists [1].
• Four-corner fusion provides improvements in pain and subjective outcome measures for patients with symptomatic and appropriately staged SLAC or SNAC wrists [1].
• Limited carpal fusion is favored over proximal row carpectomy in patients treated for SNAC and SLAC wrist conditions, except for flexion-extension and grip strength in women [4].
• Trapeziometacarpal joint arthritis and SLAC wrist may be treated either simultaneously or in stages [16].
• Distal scaphoid resection is a durable procedure with good long-term results for arthritis secondary to scaphoid nonunion [19].
• 94% of patients remained satisfied after distal scaphoid resection for arthritis secondary to scaphoid nonunion [19].
• No further wrist collapse or radiocarpal arthritis developed after distal scaphoid resection for arthritis secondary to scaphoid nonunion [19].
• Successful scaphoid reconstruction in SNAC wrists shifts the load back onto the proximal pole and interrupts the otherwise inevitable degenerative pattern in scaphoid nonunions [10].

Complications

• Proximal row carpectomy and four-corner fusion both provide improvements in pain and subjective outcome measures for patients with symptomatic and appropriately staged SLAC or SNAC wrists [1].
• Limited carpal fusion is favored over proximal row carpectomy for SNAC and SLAC wrist conditions, except for flexion-extension and grip strength in women [4].
• SNAC wrists exhibit a decreased sagittal lunotriquetral angle compared to SLAC wrists, indicating a distinct pathomechanism of carpal instability [5].
• Distal scaphoid resection arthroplasty produced favorable, long-term clinical results for degenerative arthritis secondary to scaphoid nonunion [29].
• Distal scaphoid resection arthroplasty did not result in noteworthy wrist collapse for degenerative arthritis secondary to scaphoid nonunion [29].

Recovery

• Scaphoid excision and four-corner fusion is indicated for the treatment of SLAC/SNAC wrist when significant pain is refractory to nonoperative measures [3].
• Successful scaphoid reconstruction interrupts the otherwise inevitable degenerative pattern in scaphoid nonunions [10].
• 94% of patients remained satisfied following distal scaphoid resection for arthritis secondary to scaphoid nonunion [19].
• No further wrist collapse or radiocarpal arthritis developed following distal scaphoid resection for arthritis secondary to scaphoid nonunion [19].
• Functional results of four-corner fusion for SLAC and SNAC wrist are good at long-term follow-up [30].
• Radiographic changes in the radiolunate joint occur in 73% of patients following four-corner fusion for SLAC and SNAC wrist [30].

Key Evidence

• [L4] Both procedures provide improvements in pain and subjective outcome measures for patients with symptomatic and appropriately staged SLAC or SNAC wrists. [1] (10.1177/1753193408100954)
• [L4] Our data demonstrate that midcarpal arthrodesis is a reliable procedure for treating SLAC- and SNAC-wrists in stages II and III and, furthermore, one which preserves some range of motion. [2] (10.1097/01.sap.0000194245.94684.54)
• [L4] Scaphoid excision and four-corner fusion is indicated for the treatment of the SLAC/SNAC wrist when significant pain is refractory to nonoperative measures. [3] (10.1053/otor.2003.36321)
• [L3] Among patients treated for SNAC and SLAC wrist conditions, findings are in favour of Limited Carpal Fusion compared to Proximal Row Carpectomy, except for flexion-extension and grip strength in women. [4] (10.1186/s13018-023-04177-7)
• [L4] SNAC wrists differ from SLAC wrists in exhibiting a decreased sagittal lunotriquetral angle, indicating a distinct pathomechanism of carpal instability. [5] (10.1186/s12891-025-08652-6)
• [L3] Bone density was greater at the capitolunate joint, the radial styloid, and the radiolunate joint in SNAC wrists compared to controls. [6] (10.2106/jbjs.22.01350)
• [L4] Radiographic classification of SLAC wrist has moderate reliability and reproducibility, whereas classification of SNAC wrist has limited reliability. [7] (10.1177/1753193413484629)
• [L5] The diagnosis of SLAC should be reserved for patients in whom a traumatic disruption of the proximal carpal row has initiated the defined sequence of arthritic change outlined by Watson and Ballet. [8] (10.1016/j.jhsa.2015.06.110)
• [L3] Patients with SLAC wrist were more likely to be male and have a history of trauma compared to patients with first CMC OA. [9] (10.1177/1558944718788672)
• [L4] Successful scaphoid reconstruction in SNAC wrists shifts the load back onto the proximal pole and interrupts the otherwise inevitable degenerative pattern in scaphoid nonunions. [10] (10.1016/j.jhsa.2018.06.104)
• [Paper] Staging systems for SNAC wrist lack agreement. [11] (10.1007/s12593-012-0062-2)
• [L4] The procedure is indicated for SLAC II or SLAC III wrists as an intermediate step to relieve pain and preserve functional motion. [12] (10.1016/j.arthro.2012.04.108)
• [L5] There is currently no scientific evidence that a scapholunate ligament injury visualized arthroscopically, without static x-ray changes, inevitably leads to SLAC wrist. [13] (10.1016/j.jhsa.2011.01.018)
• [L3] Carpal malalignment in SLAC wrists not only affects the radio- and midcarpal joints, but also extends to the third carpometacarpal joint, with malalignment evident in both the sagittal and coronal planes. [14] (10.1016/j.jhsa.2024.09.021)
• [L4] It also differentiates SOAC from SLAC wrist and discusses how the SOAC staging system can guide treatment decisions. [15] (10.5435/jaaos-d-25-01408)
• [L4] Trapeziometacarpal joint arthritis and SLAC wrist may be treated either simultaneously or in stages. [16] (10.1016/j.jhsa.2021.05.002)
• [L4] It is mostly indicated as a palliative procedure in elderly patients with posttraumatic SNAC or SLAC wrist with limited functional demands. [17] (10.1055/s-0032-1329615)
• [L5] Despite its significant limitations, the Watson and Ballet classification of SLAC wrist osteoarthritis is widely accepted, simple, and a well-recognized guide to treatment. [18] (10.1097/corr.0000000000000451)
• [L4] Distal scaphoid resection is a durable procedure with good long-term results. 94% of patients remained satisfied, and no further wrist collapse or radiocarpal arthritis developed. [19] (10.1016/s0363-5023(11)60002-6)
• [L4] The procedure studied may have advantages in relieving pain while preserving wrist motion for SLAC stage 2 or 3 disease. [20] (10.1177/1558944717725383)
• [L3] The authors prefer proximal row carpectomy for SLAC wrists with preserved capitate head cartilage due to socio-economic benefits, lower complication rates, and procedural ease. [25] (10.1177/1753193408087116)
• [L4] ARARC may be a viable surgical option for patients with SLAC wrist who desire a minimally invasive procedure. [28] (10.1055/s-0034-1373839)
• [L4] Distal scaphoid resection arthroplasty produced favorable, long-term clinical results and did not result in noteworthy wrist collapse. [29] (10.1016/j.jhsa.2014.05.031)
• [L4] Functional results were good at long-term follow-up despite radiographic changes in the radiolunate joint in 73% of patients. [30] (10.1177/1558944716681949)

References

[1] Proximal Row Carpectomy vs Four Corner Fusion for Scapholunate (Slac) or Scaphoid Nonunion Advanced Collapse (Snac) Wrists: A Systematic Review of Outcomes. Journal of Hand Surgery (European Volume). 2009. DOI: 10.1177/1753193408100954

[2] Long-Term Results of Midcarpal Arthrodesis in the Treatment of Scaphoid Nonunion Advanced Collapse (SNAC-Wrist) and Scapholunate Advanced Collapse (SLAC-Wrist). Annals of Plastic Surgery. 2006. DOI: 10.1097/01.sap.0000194245.94684.54

[3] Scaphoid excision and four-corner fusion in the SLAC/SNAC wrist. Operative Techniques in Orthopaedics. 2003. DOI: 10.1053/otor.2003.36321

[4] Limited intercarpal fusion versus proximal row carpectomy in the treatment of SLAC or SNAC wrist, results after 3.5 years. Journal of Orthopaedic Surgery and Research. 2023. DOI: 10.1186/s13018-023-04177-7

[5] Computer-aided three-dimensional analysis of carpal alignment in scaphoid nonunion advanced collapse wrists: A comparative study with scapholunate advanced collapse and healthy wrists. BMC Musculoskeletal Disorders. 2025. DOI: 10.1186/s12891-025-08652-6

[6] Quantitative 3-D CT Demonstrates Distal Row Pronation and Translation and Radiolunate Arthritis in the SNAC Wrist. Journal of Bone and Joint Surgery. 2023. DOI: 10.2106/jbjs.22.01350

[7] Reproducibility of radiographic classification of scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC) wrist. Journal of Hand Surgery (European Volume). 2013. DOI: 10.1177/1753193413484629

[8] Scapholunate Advanced Collapse: Nomenclature and Differential Diagnosis. The Journal of Hand Surgery. 2015. DOI: 10.1016/j.jhsa.2015.06.110

[9] The Epidemiology of Scapholunate Advanced Collapse. HAND. 2018. DOI: 10.1177/1558944718788672

[10] Long-Term Results of Scaphoid Grafting in 52 SNAC Wrists: Should We Cut Down on Salvage Procedures?. The Journal of Hand Surgery. 2018. DOI: 10.1016/j.jhsa.2018.06.104

[11] Scaphoid Nonunion Advanced Collapse Classifications: A Reliability Study. Journal of Hand and Microsurgery. 2012. DOI: 10.1007/s12593-012-0062-2

[12] Arthroscopic Wrist Debridement and Radial Styloidectomy for Late‐stage Scapholunate Advanced Collapse Wrist (SS‐49). Arthroscopy. 2012. DOI: 10.1016/j.arthro.2012.04.108

[13] Scapholunate Advanced Collapse and Scaphoid Nonunion Advanced Collapse Arthritis—Update on Evaluation and Treatment. The Journal of Hand Surgery. 2011. DOI: 10.1016/j.jhsa.2011.01.018

[14] Comparative Computer-Aided Analysis of Three-Dimensional Carpal Alignment in Scapholunate Advanced Collapse and Healthy Wrists. The Journal of Hand Surgery. 2025. DOI: 10.1016/j.jhsa.2024.09.021

[15] Scaphotrapeziotrapezoid Joint Osteoarthritis: Differentiating SOAC Wrist From SLAC Wrist. Journal of the American Academy of Orthopaedic Surgeons. 2026. DOI: 10.5435/jaaos-d-25-01408

[16] Combined Treatment of Trapeziometacarpal Joint Arthritis and Scapholunate Advanced Collapse Wrist. The Journal of Hand Surgery. 2022. DOI: 10.1016/j.jhsa.2021.05.002

[17] Scaphoidectomy and Capsulodesis for SNAC or SLAC Stage II. Journal of Wrist Surgery. 2012. DOI: 10.1055/s-0032-1329615

[18] Classifications in Brief: Watson and Ballet Classification of Scapholunate Advanced Collapse Wrist Arthritis. Clinical Orthopaedics & Related Research. 2018. DOI: 10.1097/corr.0000000000000451

[19] Distal Scaphoid Resection for Arthritis Secondary to Scaphoid Nonunion: A Twenty-year Experience. The Journal of Hand Surgery. 2011. DOI: 10.1016/s0363-5023(11)60002-6

[20] Arthroscopic Wrist Debridement and Radial Styloidectomy for Advanced Scapholunate Advanced Collapse Wrist: Long-term Follow-up. HAND. 2017. DOI: 10.1177/1558944717725383

[25] Proximal Row Carpectomy Versus Four-Corner Arthrodesis as a Treatment for SLAC (Scapholunate Advanced Collapse) Wrist. Journal of Hand Surgery (European Volume). 2008. DOI: 10.1177/1753193408087116

[28] Arthroscopic Resection Arthroplasty of the Radial Column for SLAC Wrist. Journal of Wrist Surgery. 2014. DOI: 10.1055/s-0034-1373839

[29] Distal Scaphoid Resection for Degenerative Arthritis Secondary to Scaphoid Nonunion: A 20-Year Experience. The Journal of Hand Surgery. 2014. DOI: 10.1016/j.jhsa.2014.05.031

[30] Ten-Year Minimum Follow-Up of 4-Corner Fusion for SLAC and SNAC Wrist. HAND. 2016. DOI: 10.1177/1558944716681949