Erik Woelber1,2, Audrey Martin3, Douglas Van Citters3, Craig Luplow4, Michael Githens5, Charlotte Kohn6, Yong Jun Kim7, Heang Oy7, Jim Gollogly7. 1. University of Washington School of Medicine, Seattle, WA, USA. woelber@ohsu.edu. 2. Department of Orthopedics, OHSU, 3147 S.W. Sam Jackson Park Road, Portland, OR, 97239, USA. woelber@ohsu.edu. 3. Dartmouth Biomedical Engineering Center, Hanover, NH, USA. 4. Duke University Department of Surgery, Durham, NC, USA. 5. University of Washington Department of Orthopaedic Surgery, Seattle, WA, USA. 6. Brighton & Sussex Medical School, Brighton, UK. 7. Children's Surgical Centre, Phnom Penh, Cambodia.
Abstract
PURPOSE: Since its development in 1999, the SIGN nail has been used in over 190,000 surgeries spanning 55 countries. To date, however, evaluation of SIGN nail outcomes has been limited to small prospective studies or large retrospective studies using SIGN's online database. This study uses the experience of a single, independent Cambodian surgical clinic to characterize common complications, provide commentary on ways to reduce the risk of those complications, and determine whether several observed nail fractures were due to metallurgic defects. METHODS: Clinic medical records were queried to identify complications in patients with SIGN nails. Data was abstracted including age, sex, mechanism of injury, and latency between injury, primary implantation, and presentation with a complication. Two nails that fractured in vivo were analyzed by light microscopy, scanning electron microscopy, and polarized light microscopy after chemical etching. RESULTS: Fifty-four complications in 51 patients were identified. The most common complications were non-union (n = 26, 48%), infection (n = 16, 30%), flexion limitation (n = 11, 20%), nail fracture (n = 4, 7%), delayed union (n = 4, 7%), and malunion (n = 4, 7%). Other complications included broken or floating screws. Fractography revealed that two of the fractured nails most likely failed by fatigue followed by fast fracture at the site of non-union. We found no evidence of intrinsic nail defects. We identified multiple inconsistencies between SIGN's database and independent clinic records. CONCLUSIONS: Non-union and infection were common relative to all complications. Based on radiographic review, risk for non-union and malunion can be minimized by selecting an appropriate nail diameter, using multiple interlocking screws, and employing the correct implant and approach for fracture morphology when using SIGN nails. Nail fractures were unlikely to be caused by metallurgical flaws. Further study is necessary to determine the appropriate management of non-unions based on radiographic and clinical factors.
PURPOSE: Since its development in 1999, the SIGN nail has been used in over 190,000 surgeries spanning 55 countries. To date, however, evaluation of SIGN nail outcomes has been limited to small prospective studies or large retrospective studies using SIGN's online database. This study uses the experience of a single, independent Cambodian surgical clinic to characterize common complications, provide commentary on ways to reduce the risk of those complications, and determine whether several observed nail fractures were due to metallurgic defects. METHODS: Clinic medical records were queried to identify complications in patients with SIGN nails. Data was abstracted including age, sex, mechanism of injury, and latency between injury, primary implantation, and presentation with a complication. Two nails that fractured in vivo were analyzed by light microscopy, scanning electron microscopy, and polarized light microscopy after chemical etching. RESULTS: Fifty-four complications in 51 patients were identified. The most common complications were non-union (n = 26, 48%), infection (n = 16, 30%), flexion limitation (n = 11, 20%), nail fracture (n = 4, 7%), delayed union (n = 4, 7%), and malunion (n = 4, 7%). Other complications included broken or floating screws. Fractography revealed that two of the fractured nails most likely failed by fatigue followed by fast fracture at the site of non-union. We found no evidence of intrinsic nail defects. We identified multiple inconsistencies between SIGN's database and independent clinic records. CONCLUSIONS: Non-union and infection were common relative to all complications. Based on radiographic review, risk for non-union and malunion can be minimized by selecting an appropriate nail diameter, using multiple interlocking screws, and employing the correct implant and approach for fracture morphology when using SIGN nails. Nail fractures were unlikely to be caused by metallurgical flaws. Further study is necessary to determine the appropriate management of non-unions based on radiographic and clinical factors.