Correction of Humpback Deformities in Patients With Scaphoid Nonunion Using 1,2-Intercompartmental Supraretinacular Artery Pedicled Vascularized Bone Grafting With a Dorsoradial Approach

Scaphoid Nonunions: Local Vascularized Bone Flaps

If untreated, scaphoid nonunions may progress to scaphoid nonunion advanced collapse in a substantial portion of cases and may require salvage procedures. Multiple different techniques have been described to address scaphoid nonunion. Vascularized bone flaps (VBFs) are associated with faster time to union compared with nonvascularized grafts. Because these are local pedicled flaps, they do not require microsurgical anastomoses and should be within the armamentarium of all hand surgeons. Appropriately chosen local VBFs, can achieve union rates up to 90% to 100% in appropriately selected patients.

Predictors of Failure for Vascularized and Nonvascularized Bone Grafting of Scaphoid Nonunions: A Systematic Review

Objective  This article compares predictors of failure for vascularized (VBG) and nonvascularized bone grafting (NVBG) of scaphoid nonunions. Methods  We conducted a systematic literature review of outcomes after VBG and NVBG of scaphoid nonunion. Fifty-one VBG studies ( N  = 1,419 patients) and 81 NVBG studies ( N  = 3,019 patients) met the inclusion criteria. Data were collected on surgical technique, type of fixation, time from injury to surgery, fracture location, abnormal carpal posture (humpback deformity and/or dorsal intercalated segmental instability [DISI]), radiographic parameters of carpal alignment, prior failed surgery, smoking status, and avascular necrosis (AVN) as defined by punctate bleeding, magnetic resonance imaging (MRI) with contrast, MRI without contrast, X-ray, and histology. Meta-analysis of proportions was conducted with Freeman-Tukey double arcsine transformation. Multilevel mixed-effects analyses were performed with univariable and multivariable Poisson regression to identify confounders and evaluate predictors of failure. Results  The pooled failure incidence effect size was comparable between VBG and NVBG (0.09 [95% confidence interval [CI] 0.05-0.13] and 0.08 [95% CI 0.06-0.11], respectively). Humpback deformity and/or DISI (incidence-rate radios [IRRs] 1.57, CI: 1.04-2.36) and lateral intrascaphoid angle (IRR 1.21, CI: 1.08-1.37) were significantly associated with an increased VBG failure incidence. Time from injury to surgery (IRR 1.09, CI: 1.06-1.12) and height-to-length (H/L) ratio (IRR 53.98, CI: 1.16-2,504.24) were significantly associated with an increased NVBG failure incidence, though H/L ratio demonstrated a wide CI. Decreased proximal fragment contrast uptake on MRI was a statistically significant predictor of increased failure incidence for both VBG (IRR 2.03 CI: 1.13-3.66) and NVBG (IRR 1.39, CI: 1.16-1.66). Punctate bleeding or radiographic AVN, scapholunate angle, radiolunate angle, and prior failed surgery were not associated with failure incidence for either bone graft type ( p > 0.05). Conclusion  Humpback deformity and/or DISI and increasing lateral intrascaphoid angle may be predictors of VBG failure. Time from injury to surgery may be a predictor of NVBG failure. AVN as defined by decreased contrast uptake on MRI may be a marker of increased failure risk for both bone graft types.

The progress in the classification and treatment of scaphoid nonunion

Scaphoid fracture is the most common carpal fracture, accounting for 50%-80% of all carpal fractures in the Youngers and manual workers. The nonunion rate of scaphoid fractures was approximately 10-15%. Scaphoid nonunion can lead to wrist deformity, wrist collapse, ischemic necrosis, and traumatic osteoarthritis resulting in the loss of wrist function and seriously influence the patients' lives. Achieving bony union is essential for the treatment of scaphoid nonunion. Although many surgical procedures including various forms of bone grafting have been developed to improve bony union, there is no conclusion about which method is the most effective and optimal. In this review, we provide an overview of the diagnostic, classification and progress in the treatments of scaphoid nonunion fractures.

Comparison between Vascular and Non-Vascular Bone Grafting in Scaphoid Nonunion: A Systematic Review

Background: Scaphoid fractures correspond to 60% of all carpal fractures, with a risk of 10% to progress towards non-union. Furthermore, ~3% present avascular necrosis (AVN) of the proximal pole, which is one of the main complications related to the peculiar vascularization of the bone. Scaphoid non-union can be treated with vascularized and non-vascularized bone grafting. The aim of the study is to evaluate the rates of consolidation of scaphoid non-union treated using two types of grafts. Methods: A systematic review of two electronic medical databases was carried out by two independent authors, using the following inclusion criteria: non-union of the proximal pole of the scaphoid bone, treated with vascular bone grafting (VBG) or non-vascular bone grafting (NVBG), with or without the use of internal fixation, patients aged ≥ 10 years old, and a minimum of 12 months follow-up. Research of any level of evidence that reports clinical results and regarding non-union scaphoid, either using vascularized or non-vascularized bone grafting, has been included. Results: A total of 271 articles were identified. At the end of the first screening, 104 eligible articles were selected for the whole reading of the text. Finally, after reading the text and the control of the reference list, we selected 26 articles following the criteria described above. Conclusions: The choice of the VBG depends mainly on the defect of the scaphoid and on the surgeon’s knowledge of the different techniques. Free vascular graft with medial femoral condyle (MFC) seems to be a promising alternative to local vascularized bone grafts in difficult cases.

Double trapezia sign: A new radiologic sign of scaphoid nonunion

In scaphoid nonunion, pseudarthrosis and sclerotic change occur at the nonunion site. These changes make a distal fragment look like a trapezium on plain radiographs and we called this phenomenon the double trapezia sign. The purpose of this study was to estimate the diagnostic reliability of the double trapezia sign and its clinical and prognostic implications for the scaphoid nonunion.A retrospective review of 124 patients who underwent surgical treatment because of scaphoid nonunion between January 2007 and December 2017 was performed. Two hand surgeons and 1 musculoskeletal radiologist reviewed preoperative plain radiographs independently. Each observer evaluated the plain radiographs in 2 separate sessions at least 3 weeks apart to assess intraobserver and interobserver reliabilities of the double trapezia sign. To assess clinical and prognostic implications of the double trapezia sign, the patients were divided into the positive and nonpositive groups, and several variables such as age, sex, duration of nonunion, size of the distal fragment, avascular necrosis (AVN) of the proximal fragment, type of bone graft, healing time, and failure rate were compared between the 2 groups.The kappa values of intraobserver and interobserver reliabilities were >0.8, corresponding to almost perfect agreement. There were 58 patients in the positive group and 66 patients in the nonpositive group. The mean duration of nonunion was 38.5 months in the positive group and 12.2 months in the nonpositive group (P < .001). The size of distal fragment was 49.6% and 60.9%, respectively (P < .001). The AVN of proximal fragment was 24.1% and 54.5%, respectively (P = .001). The mean healing time was 4.1 and 6.4 months, respectively (P < .001). The failure rate was 13.8% and 27.3%, respectively (P = .066).In conclusion, the double trapezia sign is a valuable radiographic sign of scaphoid nonunion. The double trapezia sign is easily identifiable on plain radiographs and has excellent intra- and interobserver reliabilities. The positive double trapezia sign implies mid-waist nonunion, long duration of nonunion, less possibility of AVN, and favorable postoperative prognosis.