Scaphoid fracture nonunion: correlation of radiographic imaging, proximal fragment histologic viability evaluation, and estimation of viability at surgery: diagnosis of scaphoid pseudarthrosis. Int Orthop. 2015;39:67-72. [PMID: 25398469 DOI: 10.1007/s00264-014-2579-4]

Scaphoid Nonunions Treated with Nonvascularized Bone Grafting and Screw Fixation

Background  Vascularized bone grafting with screw fixation is currently considered the treatment of choice for scaphoid nonunions with avascular necrosis (AVN) of the proximal pole. A viable alternative to using vascularized bone grafts for scaphoid nonunions with AVN is nonvascularized bone grafting with screw fixation. Question  What are the functional outcomes of patients with scaphoid nonunions and associated proximal pole AVN who are treated with nonvascularized distal radius bone grafting and screw fixation? Patients and Methods  Eight scaphoid nonunions with AVN, which received nonvascularized distal radius bone graft and screw fixation, underwent a retrospective review. Range of motion, strength, and Disabilities of the Arm, Shoulder, and Hand (DASH) scores were obtained. Follow-up X-rays were compared with immediate postoperative X-rays. Results  At a mean follow-up of 88.9 months, thumb palmar abduction and radial abduction were significantly higher on the operative side ( p  = 0.28 and 0.49, respectively). Extension/flexion arc was significantly lower in the operative wrist ( p  = 0.148). There was no significant difference between the operative and nonoperative sides with regard to strength. The median postoperative DASH score was 2.9 (interquartile range [IQR]: 8.3). There was no progression of osteoarthritis when immediate postoperative and follow-up X-rays were compared. Radiographic union was observed in six of the seven (85.7%) patients who were able to return to the office for follow-up radiographs. The mean scapholunate and radioscaphoid angles measured on X-rays were within normal anatomic range postoperatively. Conclusions  Using nonvascularized distal radius bone graft and screw fixation in the treatment of scaphoid nonunions with associated AVN has favorable radiologic and functional outcomes and should be considered a viable treatment option for this difficult problem.

Principles and Evaluation of Bony Unions

Nonunion is a common and costly problem. Unfortunately, there is no widely agreed upon and standardized definition for nonunion. The evaluation of bony union should start with a thorough history and physical examination. The clinician should consider patient-dependent as well as patient-independent characteristics that may influence the rate of healing and evaluate the patient for physical examination findings suggestive of bony union and infection. Radiographs and clinical examination can help confirm a diagnosis of union. When the diagnosis is in doubt, however, advanced imaging modalities as well as laboratory studies can help a surgeon determine when further intervention is necessary.

Utility of preoperative MRI for assessing proximal fragment vascularity in scaphoid nonunion

Aims

The benefit of MRI in the preoperative assessment of scaphoid proximal fragment vascularity remains controversial. The purpose of this study is to compare preoperative MRI findings to intraoperative bleeding of the proximal scaphoid.

Methods

A retrospective review of 102 patients who underwent surgery for scaphoid nonunion between January 2000 and December 2020 at a single institution were identified. Inclusion criteria were: isolated scaphoid nonunion; preoperative MRI assessing the proximal fragment vascularity; and operative details of the vascularity of the proximal fragment with the tourniquet deflated. MRI results and intraoperative findings were dichotomized as either 'yes' or 'no' for the presence of vascularity. A four-fold contingency table was used to analyze the utility of preoperative MRI with 95% confidence intervals. Relative risk was calculated for subgroups to analyze the association between variables and MRI accuracy.

Results

Preoperative MRI identified 55 proximal scaphoid fragments with ischaemia and 47 with vascularized proximal fragments. After the proximal fragment was prepared, the tourniquet was deflated and assessed for bleeding; 63 proximal fragments had no bleeding and 39 demonstrated bleeding. MRI was not reliable or accurate in the assessment of proximal fragment vascularity when compared with intraoperative assessment of bleeding. No patient or MRI factors were identified to have a statistical impact on MRI accuracy.

Conclusion

Current preoperative MRI protocols and diagnostic criteria do not provide a high degree of correlation with observed intraoperative assessment of proximal fragment bleeding. While preoperative MRI may assist in surgical planning, intraoperative assessment remains the best means for assessing proximal fragment vascularity in scaphoid nonunion. Future efforts should focus on the development of objective measures of osseous blood flow that may be performed intraoperatively.

Perfusion of the proximal scaphoid pole: correlation between preoperative ge-MRI and intraoperative findings

BACKGROUND

Gadolinium enhanced MRI (ge-MRI) is considered as gold standard for perfusion evaluation in case of scaphoid nonunion (SNU). However, its clinical value and specificity is still not clearly evaluated. This study compares preoperative ge-MRI-based perfusion assessment and intraoperative proximal pole (PP) perfusion after scaphoid reconstruction by vascularized bone grafts. In addition, the postoperative osseous consolidation (OC) was correlated to intraoperative perfusion findings.

METHODS

Between 08/2010 and 01/2020, 60 of 271 patients with scaphoid nonunion received a vascularized radius bone graft for reconstruction. Medical reports were checked for intra-op perfusion findings. Consolidation rate was assessed at mean follow-up of 3 months by CT evaluation. In 50 cases (83.2%), complete medical and radiological history could be obtained. Preoperative ge-MRI was reevaluated by a blinded radiologist for advanced analysis of sensitivity and specificity.

RESULTS

Preoperative ge-MRI (initial finding, IF) showed 23 avascular, 20 malperfused, and seven vital PP. Blinded radiological follow-up (second finding, SF) revealed 14 avascular, 28 malperfused, and 8 vital PP, with a concordance of 65.3% (n = 35). After correlation with the intra-op findings, a specificity of preoperative ge-MRI of 76.5% (IF) and 88.2 (SF), respectively, was revealed for exclusion of avitality. For detection of malperfusion, there was a sensitivity of 92.7% (IF) and 85.4% (SF), respectively. Complete OC was seen 12 weeks postoperatively in 37 (73.5%), partial OC in 9 (18.3%), and nonunion in 4 cases (8.2%) on CT-scans. Of the 41 malperfused/avascular PP, 31 (75.6%) progressed to complete and 6 (14.6%) to partial (at least 2 adjacent CT-layers of 2 mm) OC, with 4 nonunions.

CONCLUSION

The sensitivity and specificity of ge-MRI for detection/ exclusion of malperfusion/avitality of the PP was lower than expected. Therewith, the intraoperative assessment of PP perfusion regains a high value in decision-making for the appropriate graft. We recommend preservation of the dorsal radial vascular plexus initially until the vascularity of the proximal pole has been estimated. Patient education for all contingencies and retraction options should be obtained.

Clinical and Patient-Reported Outcomes After Hybrid Russe Procedure for Scaphoid Nonunion

Background: Hybrid Russe technique for the treatment of scaphoid nonunion with humpback deformity has been described with a reported 100% union rate. We sought to evaluate the reproducibility of this technique. Methods: We completed a retrospective chart review of patients with a scaphoid waist nonunion and humpback deformity treated with the hybrid Russe technique from 2015 to 2019 with a minimum of 3-month follow-up. Twenty patients with 21 nonunions were included (mean follow-up: 7.0 months). Scapholunate angle was the primary outcome measure. Secondary outcomes included: intrascaphoid angle, radiolunate angle, pain on the visual analog scale (VAS), and Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score. Other variables included: time to computed tomography (CT) union, range of motion, and complications. Descriptive statistics were presented. Pre- and postoperative angles, VAS, and QuickDASH scores were evaluated with Wilcoxon signed rank tests. Results: The mean scapholunate angle improved -17.6° ± 6.4°. The mean intrascaphoid angle improved 28.2° ± 6.3°. The mean radiolunate angle improved 12.8° ± 8.8°. Of the 21 scaphoids, 20 (95%) demonstrated union on a CT scan. One patient was diagnosed with a nonunion. In total, 90% of patients noted symmetric range of motion compared with the contralateral side. The mean VAS pain score improved 6 ± 3 points. The mean QuickDASH score improved 10 ± 8 points. Complications (aside from nonunion) included 1 patient with persistent wrist pain that resolved with removal of hardware. Conclusions: The hybrid Russe technique for the treatment of scaphoid nonunions with humpback deformity demonstrates a 95% union rate. This technique is effective, reproducible, and may serve as an alternative to techniques that include structural grafts from distant sites.

Scaphoid Nonunion Vascularized Bone Grafting in 2021: Is Avascular Necrosis the Sole Determinant?

The decision regarding the use of vascularized bone grafting (VBG) or nonvascularized bone grafting for the treatment of scaphoid nonunion (SNU) needs guidelines based on patient- and fracture-specific risk factors. Historically, the presence of avascular necrosis was viewed as the primary indication for VBG; however, avascular necrosis is not the only indicator to determine whether VBG can improve our treatment of difficult SNU cases. The methods of detecting scaphoid avascular necrosis lack consensus and accuracy, limiting their use as decision-making tools. Additionally, many other preoperative risk factors for SNU surgery failure have been reported and require careful and standardized study, including the location of nonunion in the scaphoid proximal pole, the duration of nonunion, previous failed nonunion surgery, smoking, and fracture nonunion displacement or collapse. An appropriate study size and design are needed to determine the factors that guide the use of VBG or nonvascularized bone grafting to optimize the outcomes of SNU surgery.

Management of Proximal Pole Scaphoid Nonunions: A Critical Analysis Review

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Optimal management of nonunions of the proximal pole of the scaphoid is controversial and dependent on many patient and pathophysiologic considerations.

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If the proximal pole subchondral bone support is sufficient, options include open reduction and internal fixation, either alone or in combination with autologous nonvascularized or vascularized bone graft.

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If the proximal pole is not salvageable, replacement with osteochondral autografts or osteochondral flaps is the only option for reconstruction of the native anatomy.

Radiographic evaluation of vascularity in scaphoid nonunions: A review

Scaphoid fractures, particularly those that occur more proximally, are unreliable in achieving union due to the retrograde blood supply of the scaphoid bone. Vascular compromise is associated with the development of nonunions and avascular necrosis of the proximal pole. Due to the tenuous blood supply of the scaphoid, it is imperative that the vascularity be assessed when creating diagnostic and treatment strategies. Early detection of vascular compromise via imaging may signal impending nonunion and allow clinicians to perform interventions that aid in restoring perfusion to the scaphoid. Vascular compromise in the scaphoid presents a diagnostic challenge, in part due to the non-specific findings on plain radiographs and computed tomography. Magnetic resonance imaging techniques have dramatically improved our ability to assess the blood supply to the scaphoid and improve time to intervention. This review aims to summarize these advances and highlights the importance of imaging in assessing vascular compromise in scaphoid nonunion and in reperfusion following surgical intervention.

Pedicled vascularized bone grafts compared with xenografts in the treatment of scaphoid nonunion

INTRODUCTION

Fractures of the scaphoid account for 60-70% of all wrist bone fractures. The results of treatment in terms of bone healing vary depending on the type and location of the fracture, the time elapsed since the injury, the type of surgical treatment. Nonunion occurs in 5-15% of the cases on average. The purpose of this paper is to compare the surgical techniques and results of treating scaphoid nonunion (SNU) with osteoplastic xenografts of bovine origin or a vascularized autograft of the distal part of the dorsal radius.

METHODS

We compare two groups of patients with symptomatic SNU, treated surgically with either a vascularized graft (n = 15) or a xenograft of bovine origin (n = 15). In the presurgical stage, the demographic characteristics of the patients, the time elapsed between injury and surgery, and classification of the injury (Schonberg, Herbert-Fisher, and Geissler-Slade) were recorded. One year following surgery, bone healing, total duration of the treatment, complications, the Mayo wrist score, and answers to the DASH questionnaire were analyzed.

RESULTS

No statistically significant differences between the two groups of patients were observed for bone healing (86.7% vs 80%) or functional results. A highly significant difference was observed with respect to duration of the surgical intervention in favor of xenografts.

CONCLUSION

The xenograft method is simple and relatively acceptable, providing good results in terms of healing and functionality.

Bone density measurements from CT scans may predict the healing capacity of scaphoid waist fractures

Aims

We quantitatively compared the 3D bone density distributions on CT scans performed on scaphoid waist fractures subacutely that went on to union or nonunion, and assessed whether 2D CT evaluations correlate with 3D bone density evaluations.

Methods

We constructed 3D models from 17 scaphoid waist fracture CTs performed between four to 18 weeks after fracture that did not unite (nonunion group), 17 age-matched scaphoid waist fracture CTs that healed (union group), and 17 age-matched control CTs without injury (control group). We measured the 3D bone density for the distal and proximal fragments relative to the triquetrum bone density and compared findings among the three groups. We then performed bone density measurements using 2D CT and evaluated the correlation with 3D bone densities. We identified the optimal cutoff with diagnostic values of the 2D method to predict nonunion with receiver operating characteristic (ROC) curves.

Results

In the nonunion group, both the distal (100.2%) and proximal (126.6%) fragments had a significantly higher bone density compared to the union (distal: 85.7%; proximal: 108.3%) or control groups (distal: 91.6%; proximal: 109.1%) using the 3D bone density measurement, which were statistically significant for all comparisons. 2D measurements were highly correlated to 3D bone density measurements (Spearman’s correlation coefficient (R) = 0.85 to 0.95). Using 2D measurements, ROC curve analysis revealed the optimal cutoffs of 90.8% and 116.3% for distal and proximal fragments. This led to a sensitivity of 1.00 if either cutoff is met and a specificity of 0.82 when both cutoffs are met.

Conclusion

Using 3D modelling software, nonunions were found to exhibit bone density increases in both the distal and proximal fragments in CTs performed between four to 18 weeks after fracture during the course of treatment. 2D bone density measurements using standard CT scans correlate well with 3D models. In patients with scaphoid fractures, CT bone density measurements may be useful in predicting the likelihood of nonunion. Cite this article: Bone Joint J 2020;102-B(9):1200–1209.

Outcomes of Local Bone Graft and Fixation of Proximal Pole Scaphoid Nascent Nonunions and Nonunions

Background  Fractures of the proximal pole of the scaphoid have an increased risk of nonunion due to its tenuous blood supply. The optimal treatment of proximal pole scaphoid nonunions remains controversial. Objectives  To review a single surgeon's experience with proximal pole scaphoid nascent nonunions (delayed unions) and nonunions that underwent surgical fixation with a cannulated headless compression screw and local autologous bone graft from the distal radius. Patients and Methods  After obtaining Institutional Review Board approval, the electronic medical record of one tertiary care center was queried for patients with the diagnosis of "proximal pole scaphoid fractures" who underwent surgical fixation by a single surgeon over an 11-year period (2006-2017). Fifteen patients met initial query criteria; upon review of records, four patients were excluded due to the acute nature of the fracture, and one was excluded as surgical fixation included a vascularized bone graft. Results  The final study cohort consisted of 10 patients with a total of 10 proximal pole scaphoid nonunions. Almost all of the patients in this study were male (9/10 [90%]), and sporting activities were the most common mechanism of injury (8/10 [80%]). Volumetric measurements of the scaphoid fractures on computed tomography (CT) revealed that the mean total volume of the scaphoid was 2.4 ± 0.48 cm ³ and the mean volume of the proximal pole fragment was 0.38 ± 0.15 cm ³ . Postoperative CT scans were performed at a mean of 12.4 weeks (range: 8-16 weeks), with seven (7/10 [70%]) showing signs of complete union and three (3/10 [30%]) demonstrating partial union. None of the patients required additional procedures and there were no complications. Conclusions  Our results suggest that proximal pole scaphoid fractures with delayed union and nonunion treated with surgical fixation and autologous local bone graft heal without the need for more complex vascularized procedures. The volume of the proximal pole fragment did not correlate with increased risk of ongoing nonunion after the index procedure. Level of Evidence  This is a Level IV, case series study.

Scaphoid Reconstruction

Surgical strategies for scaphoid nonunions become more complex based on time from injury to treatment. The decision-making process, however, can follow a logical sequence. Scaphoid nonunions less than 1 year after trauma and no carpal malalignment can be treated with percutaneous screw fixation under fluoroscopic and/or arthroscopic guidance. Reinterventions or patients with avascular proximal poles that do not need substantial grafts are reliably treated with pedicle vascularized bone grafts. Resection of the distal pole of the scaphoid is a good option in old nonunions or after a failed scaphoid procedures. When there are radioscaphoid degenerative changes, salvage procedures such as proximal row carpectomy (PRC) should be considered.

Review article: the differential diagnosis of bone marrow edema on wrist MRI

There is a large variety of conditions that can result in 'bone marrow edema' or 'bone marrow lesions' (BML) in the wrist on magnetic resonance imaging (MRI). The combination of clinical history and the distribution of the BML can serve as a valuable clue to a specific diagnosis. This article illustrates the different patterns of BML in the wrist to serve as a useful guide when reviewing wrist MRI studies. Imaging artefacts will also be briefly covered.

Does Anyone Need a Vascularized Graft?

Many hand surgeons argue that vascularized bone grafting is indicated in proximal pole avascular necrosis, prior failed surgery, or long-standing scaphoid nonunion. However, the available evidence does not support improved treatment outcomes for vascularized bone grafting rather than traditional nonvascularized techniques. This article addresses the available evidence and examines the role of vascularized bone grafting in scaphoid nonunion treatment. It also identifies important factors that influence healing, clarifies the decision-making algorithm, and proposes areas for further research.

Dual-energy contrast-enhanced CT to evaluate scaphoid osteonecrosis with surgical correlation

To evaluate the validity of contrast enhanced dual energy CT using a lung perfusion algorithm in assessing for post-traumatic scaphoid proximal pole avascular necrosis. From Aug 2013 to Aug 2016, 18 patients (19 wrists, 16 males, 2 females, mean age 28 years) were assessed as high-risk for proximal pole scaphoid avascular necrosis by a single surgeon following a scaphoid fracture and were referred for contrast-enhanced dual energy CT. 8 wrists had specimens sent for correlative histological analysis and 11 were correlated with operative notes. Eight surgical specimens were sent to histology and showed a 100% correlation (8/8) with the DECT findings. The remaining 11 wrists that did not have a specimen sent had in-surgery findings that also correlated with DECT. A single case was discrepant (1/11) due to presence of an intra-osseous ganglion, which was reported as osteonecrosis on CT, but considered viable at surgery. No case was called viable on CT that proved to be necrotic at either surgery or histologically. Contrast-enhanced dual energy CT using a perfusion algorithm is an innovative and promising method in evaluating viability of the post-trauma proximal pole of scaphoid.

Time-dependent changes in bone healing capacity of scaphoid fractures and non-unions

The scaphoid is the most frequently fractured carpal bone and prone to non‐union due to mechanical and biological factors. Whereas the importance of stability is well documented, the evaluation of biological activity is mostly limited to the assessment of vascularity. The purpose of this study was to select histological and immunocytochemical parameters that could be used to assess healing potential after scaphoid fractures and to correlate these findings with time intervals after fracture for the three parts of the scaphoid (distal, gap and proximal). Samples were taken during operative intervention in 33 patients with delayed or non‐union of the scaphoid. Haematoxylin and Eosin (HE), Azan, Toluidine, von Kossa and Tartrate‐resistant acid phosphatase (TRAP) staining were used to characterise the samples histologically. We determined distribution of collagen 1 and 2 by immunocytochemistry, and scanning electron microscopy (SEM) was used to investigate the ultrastructure. To analyse the samples, parameters for biological healing status were defined and grouped according to healing capacity in parameters with high, partial and little biological activity. These findings allowed scoring of biological healing capacity, and the ensuing results were correlated with different time intervals after fracture. The results showed reduced healing capacity over time, but not all parts of the scaphoid were affected in the same way. For the distal fragment, regression analysis showed a statistically significant correlation between summarised healing activity scores and time from initial fracture (r = −0.427, P = 0.026) and decreasing healing activity for the gap region (r = −0.339, P = 0.090). In contrast, the analyses of the proximal parts for all patients did not show a correlation (r = 0.008, P = 0.969) or a decrease in healing capacity, with reduced healing capacity already at early stages. The histological and immunocytochemical characterisation of scaphoid non‐unions (SNUs) and the scoring of healing parameters make it possible to analyse the healing capacity of SNUs at certain time points. This information is important as it can assist the surgeon in the selection of the most appropriate SNU treatment.

Success of scaphoid nonunion surgery is independent of proximal pole vascularity

We followed 35 consecutive patients with scaphoid nonunions in a prospective longitudinal registry. All nonunions were treated with curettage, non-vascularized autogenous grafting and headless screw fixation. Preoperative magnetic resonance imaging, intraoperative bleeding points and histopathological analysis of cancellous bone in the proximal pole were recorded as measures of viability. Healing was categorized as ≥50% bony bridging on computed tomographic images in the plane of the scaphoid. Nine of 23 proximal poles demonstrated ischaemia on magnetic resonance imaging but none were interpreted as infarcted. Twenty-eight of 33 were found to have impaired vascularity as assessed by intraoperative bleeding. Fourteen of 32 demonstrated ≥50% trabecular necrosis and four of 33 demonstrated ≥50% tissue necrosis on histopathological analysis. Thirty of 33 demonstrated focal or robust remodelling activity. Despite pathological evidence of impaired vascularity in over half of the patients, 33 of the 35 scaphoids had healed by 12 weeks. We conclude that proximal pole infarction is decidedly rare and that vascularized bone grafting is seldom required.

LEVEL OF EVIDENCE

IV.

Correlation of CT imaging and histology to guide bone graft selection in scaphoid non-union surgery

INTRODUCTION

For the treatment of scaphoid non-unions (SNU), different surgical techniques, including vascularized and non-vascularized bone grafts, are applied. Besides stability, vascularity, and the biological situation at the non-union site are important for healing and the appropriate choice of treatment. We assessed the healing potential of SNUs by histological parameters and compared it to CT parameters of bone structure and fracture location. Based on the results, we developed a CT classification and a treatment algorithm to impact graft selection in SNU surgery.

PATIENTS AND METHODS

Preoperative 2D-CT reformations of 29 patients were analyzed for trabecular structure, sclerosis, and fragmentation of the proximal fragment. The fracture location was assessed on 3D-CT reconstructions and grouped in three zones depending on the potential blood supply. Samples were taken during surgery for histological evaluation. Histological parameters of bone healing were defined and a bone healing capacity score (BHC), reflecting histological bone viability, was calculated. CT findings were compared to BHC, age of SNU, and time to union.

RESULTS

Cases with trabecular structure and without fragmentation showed a statistically significant higher BHC. Time to union was significantly faster if trabecular structure was present and sclerosis was absent. In intraarticular proximal pole non-unions, where no blood supply is assumed, the BHC was statistically significantly lower and time to union was longer compared to SNUs of the other locations. A statistically significant correlation between BHC and time to union was found in the proximal and distal fragment with higher BHC associated with faster healing.

CONCLUSIONS

CT parameters of bone structure and fracture location can reflect histological healing capacity of SNUs. This can guide bone graft selection in SNU surgery.