Analysis of carpal malalignment caused by scaphoid nonunion and evaluation of corrective bone graft on carpal alignment

A comparative study of volar locking-plate fixation with corticocancellous and pure cancellous bone grafts for scaphoid nonunion with dorsal intercalated segmental instability secondary to scaphoid humpback deformity

INTRODUCTION

Bone grafts for scaphoid nonunion with deformity include cortcicocancellous or pure cancellous bone grafts. This study compared the outcomes between two types of bone grafts when employing a volar locking-plate in patients with scaphoid nonunion with dorsal intercalated segmental instability (DISI).

PATIENTS AND METHODS

This retrospective study included 34 patients with scaphoid nonunion and DISI due to humpback deformity treated between March 2017 and January 2022. Two types of bone grafts were obtained from iliac crest. Twenty of the corticocancellous (CC) group underwent a wedge-shaped graft, while 14 patients of the pure cancellous (C-only) group received graft chips. In both groups, a 1.5-mm anatomically pre-contoured locking plate was used for fixation. Radiographic evaluations included the union rate and carpal alignment including scapholunate angle (SLA), radiolunate angle (RLA), intrascaphoid angle (ISA) and scaphoid height to length ratio (HLR). Clinical assessments encompassed wrist range-of-motion, grip strength, and patient-reported outcomes.

RESULTS

Nineteen of the 20 patients in the CC group and 12 of the 14 patients in the C-only group respectively, achieving osseous union. The mean follow-up period in CC group was 14.7 (range, 12 ∼ 24) months and that in C-only group was 12.6 (range, 12 ∼ 15) months. Postoperatively, there were no significant intergroup differences of radiographic parameters including SLA (CC; 49.9° ± 6.7° vs. C-only; 48.9° ± 3.5°, P = 0.676), RLA (1.7° ± 6.4° vs. 2.4° ± 3.3°, P = 0.74), ISA (36° ± 7.5° vs. 36.6° ± 12.2°, P = 0.881), and HLR (0.54 ± 0.09 vs. 0.53 ± 0.05, P = 0.587). Clinical outcomes, including the flexion-extension arc (137° ± 30° vs. 158° ± 33°, P = 0.122), grip strength (93.4 % ± 15.4% vs. 99.5 % ± 16.7 %, P = 0.39), Quick Disabilities of the Arm, Shoulder, and Hand scores (11.2 ± 8.3 vs. 12.5 ± 7.7, P = 0.74) and Mayo Wrist Scores (81.2 ± 13.1 vs. 89 ± 11.4, P = 0.242) also showed no significant intergroup differences.

CONCLUSIONS

Volar locking-plate fixation with pure cancellous bone grafts achieved outcomes comparable to those achieved with corticocancellous bone grafts in scaphoid nonunion with deformity, possibly due to the biomechanical advantages of the volar plate to provide structural supports.

Does correction of carpal malalignment influence the union rate of scaphoid nonunion surgery?

The aim of this retrospective study was to assess the relation between carpal malalignment correction and radiological union rates in surgery for scaphoid nonunions. A total of 59 scaphoid waist fracture nonunions treated with open reduction and palmar tricortical autograft were divided according to their pre- and postoperative scapholunate (SL) and radiolunate (RL) angles. We found that carpal malalignment failed to correct in 32 of 59 (54.2%) patients despite meticulous surgical technique and placement of an appropriately sized wedge-shaped graft. In total, 43 (72.9%) fractures united at a mean of 4.47 months (range 3-11). Of the 27 fractures with postoperative SL and RL angles within the normal range, 21 united, whereas 22 of the 32 remaining fractures that failed to achieve postoperative angles within the normal range went on to union. The postoperative SL and RL angles were not related to union. Our findings suggest that in scaphoid fracture nonunion surgery, carpal malalignment may not be corrected in a substantial proportion of patients, but such correction may not be essential for bony union. Our findings also show that there is no marked collapse of the scaphoid graft in the early postoperative period.

LEVEL OF EVIDENCE

IV.

Subchondral Radial and Ulnar K-Wire Positioning With Cancellous Bone Graft Shortens Union Time in Scaphoid Waist Nonunion

BACKGROUND

Bone grafting in patients with scaphoid waist nonunion can present several technical challenges. In this study, we aimed to present a modified surgical technique for scaphoid waist nonunion, which consisted of subchondral radial and ulnar K-wires positions with cancellous bone graft, and to compare the clinical outcome of this modified technique with the conventional method.

METHODS

We retrospectively reviewed 72 patients with scaphoid waist nonunion who had been surgically treated between January 2011 and December 2020. Of these, 34 patients were treated with the modified method and 38 with the conventional method. Debridement of the nonunion site was performed using a curette, rongeur, and microburr. Two or 3 K-wires were inserted along the cancellous portion of the scaphoid in the conventional method. In the modified method, 2 K-wires were inserted along the ulnar and radial subchondral portion of the scaphoid to increase the space for bone grafting in the cancellous portion of the scaphoid. The autologous cancellous bone grafted in both the methods. Demographic, radiological, and clinical outcomes were reviewed and compared between the groups.

RESULTS

There were no significant differences in demographics and characteristics of nonunion between the 2 groups of patients. The modified method group showed significantly shorter union time than the conventional method group (conventional group: 13.0 ± 1.3 weeks, modified group: 11.4 ± 1.1 weeks; P < 0.001). The bony union rate was 97.1% for the modified method and 89.5% for the conventional method. Satisfactory clinical outcomes (excellent and good Mayo wrist scores) were achieved in 27 cases (81.8%) using the modified method and 22 cases (64.7%) using the conventional method.

CONCLUSION

Subchondral radial and ulnar K-wire positioning with cancellous bone graft (modified method) can improve the union time with satisfactory clinical outcomes in the treatment of scaphoid waist nonunion.

360-degree Arthroscopic Management of Scaphoid Pseudarthrosis: Description of Technique and Indications

Nonunion remains one of the main complications of scaphoid fractures, with no consensus being reached as to the best surgical technique for scaphoid pseudoarthrosis. Thus, different types of procedures for bone stability and biological stimulus for consolidation have been described. The use of arthroscopy for scaphoid pseudoarthrosis has advantages as it allows for treating associated injuries, preserving wrist proprioception by minimizing damage to the joint capsule and ligaments and not deteriorating the already fragile scaphoid vasculature, leading to a quick recovery. Arthroscopy was initially indicated for stable scaphoid pseudoarthroses, being used in all patterns of this condition, including unstable ones and those with flexion collapse. However, most scientific articles describe the use of arthroscopy only through the dorsal portals, creating technical difficulty in complete debridement of the site of pseudarthrosis and in placing bone graft. This study describes the 360-degree technique, which standardizes arthroscopy in scaphoid pseudoarthrosis treatment, allowing, with the use of dorsal, volar, and radial portals, direct approach to the entire circumference of the nonunion site, facilitating the debridement of the injury site, the correction of the scaphoid deformity, and the placement of a graft directly on the site of the defect, mainly in its volar region after correction of the flexion deformity. The 360-degree technique aims to help and standardize the arthroscopic procedure for scaphoid pseudarthrosis, creating a routine with defined surgery stages. Additional portals allow complete access to the entire nonunion site and better positioning of the bone graft under direct view.

Bone grafting for scaphoid nonunion surgery : a systematic review and meta-analysis

AIMS

The purpose of this systematic review was to determine the rates of union for vascularized versus non-vascularized grafting techniques in the operative management of scaphoid nonunion. Secondary aims were to determine the effect of the fixation techniques used, the source of grafting, as well as the influence of fracture location (proximal pole) and avascular necrosis (AVN).

METHODS

A search of PubMed, MEDLINE, and Embase was performed in June 2021 using the Preferred Reporting Items for Systematic Review and Meta-Analyses statement and registered using the PROSPERO International prospective register of systematic reviews. The primary outcome was union rate.

RESULTS

There were 78 studies that met the inclusion criteria with a total of 7,671 patients (87.8% male, 12.2% female). The mean age was 27.9 years (SD 3.8) and the mean follow-up was 30.9 months (SD 25.9). The mean union rate was 88.7% (95% confidence interval (CI) 85.0 to 92.5) for non-vascularized grafts versus 87.5% (95% CI 82.8 to 92.2) for vascularized grafts (p = 0.685). Pooled analysis of trial data alone found a mean union rate of 82.4% (95% CI 66.9% to 97.9%) for non-vascularized grafts and 89.4% (95% CI 84.1% to 94.7%) for vascularized grafts (p = 0.780). No significant difference was observed in union rates between any of the fixation techniques used in the studies (p = 0.502). Distal radius and iliac crest graft source had comparable mean union rates (86.9% (95% CI 83.1 to 90.7) vs 87.6% (95% CI 82.2 to 92.9); p = 0.841). Studies that excluded patients with both proximal pole fractures and AVN (n = 14) had a mean union rate of 96.5% (95% CI 94.2 to 98.9) that was significantly greater than the mean union rate of 86.8% (95% CI 83.2 to 90.4) observed in the remaining studies (p < 0.001).

CONCLUSION

Current evidence suggests vascularized bone grafting does not yield significantly superior results to non-vascularized grafting in scaphoid nonunion management. However, potential selection bias lessens the certainty of these findings. The fixation type or source of the graft used was not found to influence union rates either. Sufficiently designed and powered prospective randomized controlled trials in this area are needed. Cite this article: Bone Joint J 2022;104-B(5):549-558.

Normal ranges for measurements of the scaphoid bone from sagittal computed tomography images

This study aimed to determine normal values of three parameters commonly used to determine malunion by investigating intact scaphoids on sagittal computed tomography images from healthy individuals. We analysed 62 normal scaphoids and found the mean height-length ratio, lateral intrascaphoid angle and dorsal cortical angle to be 0.58, 27° and 128°, respectively. These measurements had good-to-excellent, poor-to-moderate and moderate-to-good inter- and intra-rater reliabilities, respectively. This study provides information on normal parameters of the scaphoid that may inform clinical decision making when assessing malunion. We suggest that the lateral intrascaphoid angle should be used with great caution as a measure of deformity.Level of evidence: III.

Structural Versus Nonstructural Bone Grafting for the Treatment of Unstable Scaphoid Waist Nonunion Without Avascular Necrosis: A Randomized Clinical Trial

PURPOSE

We evaluated the impact of structural versus nonstructural bone grafting on the time to union, scaphoid deformity correction, and clinical outcomes in adults with unstable scaphoid waist nonunion without avascular necrosis. We hypothesized that nonstructural grafting would provide earlier time to union, restoration of scaphoid anatomy, and equivalent clinical outcomes compared with structural grafting.

METHODS

We prospectively randomized 98 patients to undergo open reduction, iliac crest bone grafting with either corticocancellous (CC group) or cancellous bone only (C-only), and internal fixation using a Herbert screw. The lateral intrascaphoid angle (LISA) and scaphoid height length ratio (HLR) were measured on wrist computed tomography scans along the scaphoid longitudinal axis before surgery and an average of 84 weeks afterward. Pain, range of motion, grip strength, and Quick-Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score were measured before surgery and an average 84 weeks afterward.

RESULTS

The trajectory of scaphoid union showed a higher union rate of the C-only group at 12, 14, and 16 weeks after surgery. However, at 24 weeks after surgery, there was no difference between the groups, The union rate was 94% in patients treated with C-only and 90% with CC grafting. In patients with preoperative LISA less than 70° and/or HLR less than 0.80 (n = 53), there were no differences between the CC and C-only grafting techniques for radiographic and clinical outcomes, QuickDASH scores, and malunion rate. In patients who had preoperative LISA greater than 70° and/or HLR greater than 0.80 (n = 45), radiographic outcome measures, range of motion, and QuickDASH scores were significantly better in the CC than in the C-only group. Scaphoid malunion was observed in 9 of 22 of C-only patients (41%) and 4 of 23 of CC patients (18%).

CONCLUSIONS

The severity of the scaphoid deformity may be a factor in determining the best graft type, because this may affect the rate of successful deformity correction. Corticocancellous grafting in patients who had a high degree of scaphoid deformity provided consistent deformity correction and superior QuickDASH scores. Otherwise, C-only grafting provides earlier time to union and equivalent clinical and radiographic outcomes compared with CC grafting.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic I.

Kirschner wire versus Herbert screw fixation for the treatment of unstable scaphoid waist fracture nonunion using corticocancellous iliac bone graft: randomized clinical trial

PURPOSE

The study compared the impact of the Kirschner wires versus Herbert screw fixation on the rate of union, time to union, correction of deformity, and clinical outcome in adults with unstable scaphoid waist fracture nonunions without avascular necrosis.

METHODS

We prospectively randomized 122 patients to undergo corticocancellous iliac bone grafting and internal fixation either with multiple Kirschner wires or Herbert screw. Radiographs, clinical outcome measures (pain, range of motion, and grip strength), and the Quick DASH score were taken pre- and post-operatively.

RESULTS

The rate of the scaphoid union in the Kirschner wire group was 91% versus 88% in the Herbert group. No difference was detected between the two groups with respect to the time to union, deformity correction, pain analysis, range of motion, grip strength, return to work, and complications.

CONCLUSION

Using of multiple Kirschner wires as a fixation method for unstable scaphoid waist fracture nonunion that was treated by open reduction and corticocancellous iliac bone grafting had a shorter operative time and lower cost as compared with the Herbert screw fixation. Herbert screw fixation was technically more demanding in terms of technique than K-wires. However, because of easy application of Kirschner wires, and low cost, especially in developing countries, it may be a good alternative to Herbert screw.

Multiplanar reformation computed tomography for carpal malalignment

Correct interpretation of scaphoid axial length and carpal malalignment is difficult owing to the complex geometry of the scaphoid. Traditional measurements, such as the scapholunate angle and radiolunate angle, have shown limited reproducibility. To improve the assessment of these measurements, we used multiplanar reformation computed tomography with added average intensity projection. Four measurements for scaphoid morphology and carpal alignment were independently measured by four observers on computed tomography scans of 39 consecutive patients who were treated conservatively for scaphoid fracture. Fleiss's kappa for categorical results showed substantial agreement for the measurements of the scapholunate and radiolunate angles. Intraclass correlation coefficients were significant for measurements of the axial length, scapholunate angle and radiolunate angle. Our results suggest that multiplanar reformation computed tomography with added average intensity projection is a reliable technique for assessment of scaphoid morphology and carpal alignment. Level of evidence: II.

The Author's Technique for the Management of Unstable Scaphoid Nonunions: Tips and Tricks

This article presents historical aspects, rationale, indications, planning, and execution of anterior interpositional bone grafting technique for unstable scaphoid nonunions. The author's original technique considers four points: (1) preoperative planning based on comparative anteroposterior radiographs in maximal ulnar deviation was used to calculate resection zone, size of the graft, and scaphoid length; (2) a volar approach was used; (3) an iliac crest wedge-shaped corticocancellous graft was interposed; and (4) Kirschner wires were inserted for fixation. Contemporary refinements of the technique including a modification to treat nonunions with failed previous screw fixation with tricks and hints and results are shown.

Scapho-Capitate Ratio for Estimation of Scaphoid Length

Background: The failure of scaphoid reconstruction by restoring both length and shape may lead to carpal mal-alignment and progressive degenerative arthritis. The aim of our study is to find a reliable method to find out the scaphoid length without measuring the contralateral scaphoid. Methods: Three X-ray wrist views were collected for 51 patients without any signs suggesting any hand and wrist fractures. The scaphoid, capitate and 3^rd metacarpal bone axes lengths and carpal height were measured by 4 hand surgeons separately. Results: The scapho-capitate ratio was 1.1 ± 0.084, 1.01 ± 0.084 and 0.92 ± 0.109 for lateral, postero-anterior with ulnar deviation and postero-anterior view respectively. The ulnar deviation view had the highest reliability. Conclusions: Scapho-capitate ratio estimation is an easy and accurate measure of normal scaphoid length in situations when the scaphoid is short. It is helpful for the estimation of the size of the bone graft that need for reconstruction of the scaphoid.

A Comparison of Plate Versus Screw Fixation for Segmental Scaphoid Fractures: A Biomechanical Study

BACKGROUND

Volar locking plate fixation may offer several advantages over headless screw fixation for scaphoid nonunion, or segmental or comminuted fractures: (1) increased surface area for bony healing; (2) preserved vascularity; and (3) maintenance of a gap for graft insertion. The purpose of this study is to compare headless screw and locking plate fixation of segmental scaphoid fractures and to determine whether either fixation provides a greater mechanical advantage in osteoporotic versus nonosteoporotic bone.

METHODS

Sixteen matched-pair cadaver scaphoids were dissected from a range of osteoporotic and nonosteoporotic specimens. Scaphoids from each matched pair were randomly assigned to either volar locking plate or compression screw fixation. A 3-mm segment of bone was circumferentially excised from each scaphoid waist to simulate a segmental defect. Implants were applied, and each specimen was then loaded in axial compression. Load to failure was defined as the load required to achieve gap closure. Mechanism of failure, load to failure, and percent gap recovery were recorded for each trial.

RESULTS

Gap closure occurred in all trials. Difference in load to failure was not statistically significant between plate and screw fixation in either nonosteoporotic or osteoporotic cadaver specimens. However, percent gap recovery was significantly higher for plate fixation than for screw fixation.

CONCLUSIONS

In scaphoid fractures with segmental defect, plate and screw fixation demonstrate similar loads to failure, but plate fixation performs superiorly to screw fixation for gap recovery after an applied load to failure.

Volar Vascularized Strut Graft for Avascular Scaphoid Nonunion Using the 1,2 Intercompartmental Supraretinacular Artery

In this retrospective study, we report the preliminary results of a novel technique for volar vascularized strut grafting to treat avascular scaphoid nonunion by using the 1,2 intercompartmental supraretinacular artery through a single incision. Forty-three of 45 patients with avascular scaphoid nonunion healed at a mean of 13 weeks (range, 3 to 10 mo). Complications consisted of 1 pin tract infection that resolved with oral antibiotics and 4 cases of transient dysesthesia of the radial sensory nerve. In 4 patients with equivocal radiographs, computed tomography scans confirmed bony union. The 2 patients who remained unhealed subsequently underwent proximal row carpectomy. Two other patients had persistent pain with the progression of radiocarpal arthritis. Our technique provides good results for the treatment of avascular scaphoid fracture nonunion. Notable advantages include performance through a single incision, use of an already established vascularized bone graft, volar graft placement, and no requirement for microvascular free graft reconstruction. It also provides the surgeon with the ability to adjust the procedure intraoperatively in the event of unexpected avascularity, without requiring substantially longer operative time or additional equipment.

Editorial Commentary: The Practical Goal of Arthroscopic Osteosynthesis for the Treatment of Unstable Scaphoid Nonunion

Arthroscopic reduction with osteosynthesis using bone grafting has become a successful alternative to open techniques for the treatment of chronically unstable scaphoid nonunions. Several studies have demonstrated that arthroscopic techniques are safe and reproducible in addition to causing less soft tissue damage and providing promising short- and mid-term results. However, these techniques have limitations in restoring normal carpal alignment, especially in patients with unstable scaphoid nonunion and carpal collapse deformities, although this does not affect the recovery of clinical function. Therefore, the practical goal of arthroscopic technique should be kept in mind when treating unstable scaphoid nonunions.

Cylinder-Shaped Bone Graft for Scaphoid Nonunion

BACKGROUND

Wedge-shaped bone grafts that are internally fixed by a Herbert-type screw are a well-established surgical treatment for scaphoid nonunion. A procedure using cylinder-shaped bone grafts was also reported, but preoperative wrist functions were not assessed. In addition, it was not reported whether the humpback deformity of the scaphoid nonunion was corrected. The purpose of the current study was to compare preoperative wrist functions in cases of scaphoid nonunion with those observed at final follow-up, using cylinder-shaped bone grafts The humpback deformity of the scaphoid nonunion was also evaluated.

METHODS

We conducted a retrospective study to examine operative outcomes from 2008 to 2015. Twelve wrists in 12 patients (average age, 41 years; range, 17-67), with a mean follow-up of 19 months, were included in the current study. Cylinder-shaped bone grafts were obtained from the iliac crest with a newly designed trephine and fixed with a Herbert-type screw. We reviewed both the preoperative wrist functions and those obtained at final follow-up.

RESULTS

Union was achieved in 11 of 12 nonunion cases. Preoperative wrist functions, except for the range of wrist motion, significantly improved by final follow-up.

CONCLUSIONS

We conclude that the use of cylinder-shaped bone grafts improves preoperative wrist functions in cases of scaphoid nonunion.

A Biomechanical Comparison of Screw and Plate Fixations for Scaphoid Fractures

Background  Headless screw fixation is the current gold standard of surgical repair for scaphoid fractures. However, maintaining reduction of certain types of scaphoid fractures is challenging with a compression screw. Plate fixation may offer superior fixation in some scaphoid fractures, particularly those with comminution, nonunion, segmental bony defects, and osteopenic or osteoporotic bone. Purpose  This study questions whether method of fixation is a determinant in load to failure in segmental scaphoid fractures, and whether any fixation provides a greater mechanical advantage in simulated normal versus osteoporotic bone. Materials and Methods  Polyurethane models were fashioned to simulate scaphoids with 3-mm segmental defects. Defects were bridged by one of three constructs: a locking plate, a nonlocking plate, or a headless compression screw. Three models for each fixation construct were tested for both simulated normal and osteoporotic bone density. Load to failure was recorded as the load at which the 3-mm segmental defect was closed. Results  Gap closure occurred in all trials. In simulated normal bone, there were no statistically significant differences in load to failure between fixation methods. In simulated osteoporotic bone, the locking plate had a 28% greater load to failure as compared with screw fixation. Conclusion  While biomechanical testing shows that plate and screw fixations are equivalent in normal density bone for fixation of a segmental scaphoid defect, locking plates are superior to screw fixation in simulated osteoporotic bone models. Clinical Relevance  Plate fixation may provide superior fixation for complex scaphoid fractures, particularly in osteopenic bone.

Scaphoid nonunion: what is the role of the Zaidemberg 1,2 intercompartmental supraretinacular arterial flap?

The reported results for the treatment of scaphoid nonunions with non-vascularized grafts are based on observational studies with a high variability in union rates from 38%-100% and time to union from 6-18 weeks, and there is also a lack of a standard classification. Meta-analyses and systematic reviews have been presented to better support conclusions from large pools of data (604 to 5246 cases), but their interpretation remains limited because of lack of uniformity in the studies analysed. Several authors have presented results from the Zaidemburg flap, with highly variable outcomes despite using the same technique; union rates have ranged from 27%-100% achieved between 6.5-19 weeks. Technical details that may be responsible for the discrepancies are discussed. There is a need for a validated prognostic classification system for scaphoid nonunions that can allow comparisons between outcome studies.

Arthroscopic reconstruction for unstable scaphoid non-union

OBJECTIVE

To evaluate the results of arthroscopic reconstruction for the treatment of unstable scaphoid non-union with cancellous bone autograft.

METHODS

13 patients were treated with a mean age of 26 (18-45) years. The average time from injury until surgery was 14 (6-48) months. Preoperative and postoperative clinical and radiological parameters were evaluated. Mean follow-up was 16.8 (12-36) months.

RESULTS

Consolidation was achieved in all cases at 7 (4-10 weeks), no patient had complications or reoperations. Range of motion, pain, functional assessment (DASH questionnaire) and radiological measurements improved compared to preoperative measurements. The average range of flexion improved: flexion 71.9° (55°-80°) to 81.7° (55°-90°), extension 66.3° (30°-80°) to 84.4° (70° -90°), ulnar deviation 21.5 (10°-25°) to 25.5° (20°-45°) and radial deviation 11.9° (5°-25°) to 13.3° (10th-20th). Pain (VAS 0-10) improved from 6.8 (4-10) to 0.7 (0-3). DASH functional scale improved from 36 (12-78) to 8 (0-10). The Scapho-Lunate Angle improved from 67.7° (62°-88°) to 47° (32°-55°), and the Radio-Lunate Angle improved from 30.8° (10° -45°) to 4(0°-10°).

CONCLUSION

Treatment of unstable scaphoid non-union with cancellous bone graft assisted by arthroscopy presents good clinical results with a short period of consolidation and recovery.

Dorsal intercalated segmental instability associated with malunion of a reconstructed scaphoid

We analysed scaphoid deformity as a result of surgical treatment of scaphoid fracture nonunion and assessed the deformity associated with a dorsal intercalated segmental instability pattern of carpal malalignment. A total of 45 patients who were treated for scaphoid fracture nonunion were included in the study. The height-to-length ratio of the scaphoid was measured on computed tomographic images and used to assess scaphoid deformity. Carpal malalignment was quantified based on the radio-lunate angle. A correlation analysis between the height-to-length ratio and the radio-lunate angle was performed. Dorsal intercalated segmental instability was defined as a radio-lunate angle >15°, and a receiver operating curve analysis was used to calculate the cutoff height-to-length ratio that can be accompanied with dorsal intercalated segmental instability. Extension of the lunate increases in proportion to the flexion deformity of the scaphoid; dorsal intercalated segmental instability can occur if the height-to-length ratio of the scaphoid is >0.73.

LEVEL OF EVIDENCE

IV.

Non-structural cancellous bone graft and headless compression screw fixation for treatment of scaphoid waist non-union

PURPOSE

Scaphoid fracture commonly occurs around the mid-third of the scaphoid, and non-union of this fracture has several treatment options. The authors performed autologous cancellous bone graft from the iliac crest and headless compression screw fixation for the treatment of Mack-Lichtman type II scaphoid waist non-union. The purpose of this study was to determine whether this procedure was effective in achieving bony union and restoration of alignment.

METHODS

Medical records and radiographs of 30 patients who underwent cancellous bone graft and headless compression screw fixation for non-union of scaphoid waist fracture were retrospectively reviewed. There were 28 men and 2 women, with a mean age of 32.8 years (range: 21-63). The mean time to surgery was 10 months (range: 3-25) and mean follow-up was 37.5 months (range: 15-52). The authors analyzed bony union, lateral intrascaphoid angle, scapholunate angle, radiolunate angle and scaphoid length on radiographs and evaluated the Modified Mayo wrist score (MMWS) as a functional outcome.

RESULTS

Bony union was achieved in all cases. The lateral intrascaphoid angle improved from 40° to 32° (P<0.001). The scapholunate angle also improved from 61° to 56° (P=0.009). The radiolunate angle decreased from 8° to 4° (P=0.048) and scaphoid length increased from 22mm to 26mm (P<0.001) postoperatively. Wrist motion and MMWS improved significantly at last follow-up. However, there were no significant differences between scaphoid deformity correction angle and pre- to post-operative difference in MMWS.

CONCLUSIONS

Non-structural autologous cancellous bone graft from the iliac crest and headless screw fixation provided reliable results and can be one of the effective treatment options for patients with symptomatic Mack-Lichtman type II non-union in the mid-third of the scaphoid.

LEVEL OF EVIDENCE

Level III.

[Scaphoid pseudarthrosis : Indications for avascular iliac crest or radius bone grafts]

BACKGROUND

Operative treatment of the scaphoid nonunion includes avascular corticocancellous and cancellous bone grafts and increasingly the use of vascular pedicled and free vascular corticocancellous grafts. Especially the latter require a fair amount of operative expertise and experience in microsurgical techniques.

OBJECTIVE

Which criteria lead to the decision for or against an avascular graft used for reconstruction of scaphoid nonunion? Is our current classification system of a scaphoid pseudarthrosis able to illustrate our diagnostic potential in a way that makes us refer to operative procedures?

METHODS

Evaluation of current literature and expert opinions RESULTS: Avascular bone grafts show a high union rate as long as a sufficient vascularisation of the remaining fragments is present. In general, patients benefit from a very good functional outcome. Even revisions of failed scaphoid union may be successfully treated with an avascular bone graft. Failures of union are repeatedly experienced in treating proximal pole fractures with critical vascularisation or extensive bone loss, especially including avascular necrosis of the proximal pole (AVN). Current classification systems do not allow description and correlation of morphologic findings so as to compare results profoundly and to recommend specific procedures.

CONCLUSIONS

As long as sufficient vascularisation of remaining fragments is seen, the avascular bone graft is eligible for reconstructing scaphoid nonunion. Classification systems do not seem to reflect the status quo of diagnostic possibilities and make it difficult to provide guidelines for state-of-the-art operative procedures.

Estimating Scaphoid Lengths Using Anatomical Measurements in the Wrist

PURPOSE

In reconstructive surgery of scaphoid nonunions with humpback deformity, some surgeons recommend restoration of the normal scaphoid length whereas others overexpand the normal length to ensure carpal realignment and prevent late collapse. To be able to define overexpansion and investigate which levels of overexpansion yield optimal clinical results, a precise method for estimating the original scaphoid length is required. The purpose of this anatomic study was to investigate the precision of estimating normal scaphoid lengths based on intact adjacent bone dimensions, compared with using the contralateral scaphoid length.

METHODS

From bilateral computed tomographic scans of 28 healthy wrist pairs, 3-dimensional virtual bone models were created. The left and right scaphoid lengths were determined at the central axis. The capitate length at the central axis and the distal radius width served to derive an ipsilateral scaphoid length estimate. Estimation precision for individual cases was based on the 95% range (±1.96 × SD) of the observed differences between the actual and estimated lengths.

RESULTS

On average, the capitate length was 10% smaller than the scaphoid length; the radius width was 9% larger. Consequently, we averaged the capitate length and radius width for ipsilateral estimations. The average difference between the scaphoid length and the latter ipsilateral estimate was 0.1 mm. The average contralateral scaphoid length difference was also 0.1 mm. Estimation precisions, however, were ±2.2 and ±1.4 mm, respectively.

CONCLUSIONS

Scaphoid length estimation based on the contralateral scaphoid is more precise than the estimating scaphoid length using the ipsilateral radius and capitate.

CLINICAL RELEVANCE

Scaphoid overexpansion can be ensured if the restored length is at least 1.4 mm longer than the contralateral length. This may be valuable information when establishing a target length for reconstruction and investigating the consequences of scaphoid overexpansion on clinical function, such as range of motion, which are currently unknown.

Analysis of deformity in scaphoid non-unions using two- and three-dimensional imaging

Pre-operative assessment of the deformity in scaphoid non-unions influences surgical decision-making. To characterize deformity, we used three-dimensional computed tomographic modelling in 28 scaphoid non-unions, and quantified bone loss, dorsal osteophyte volume and flexion deformity. We further related these three-dimensional parameters to the intrascaphoid and capitate-lunate angles, and stage of scaphoid non-union advanced collapse assessed on conventional two-dimensional images and to the chosen surgical procedure. Three-dimensional flexion deformity (mean 26°) did not correlate with intrascaphoid and capitate-lunate angles. Osteophyte volume was positively correlated with bone loss and stage of scaphoid non-union advanced collapse. Osteophyte volume and bone loss increased over time. Three-dimensional modelling enables the quantification of bone loss and osteophyte volume, which may be valuable parameters in the characterization of deformity and subsequent decision-making about treatment, when taken in addition to the clinical aspects and level of osteoarthritis.

TYPE OF STUDY/LEVEL OF EVIDENCE

Level IV.

Treatment of Scaphoid Nonunion: A Systematic Review of the Existing Evidence

PURPOSE

To determine by systematic review the optimal treatment of scaphoid nonunion.

METHODS

We conducted a systematic review of the literature with a meta-analysis of proportions to investigate the comparative effectiveness of different surgical techniques.

RESULTS

A total of 48 publications (1,602 patients) met the eligibility criteria. Vascularized and nonvascularized bone grafts had an estimated union incidence of 92% and 88%, respectively. Distal radius and iliac crest bone grafts had similar union rates (89% and 87%, respectively) but harvesting of iliac crest bone grafts had more complications. Both screw and K-wire fixation had a higher incidence of union (88% and 91%, respectively) than no fixation (79%). No approach was statistically different. Patients fixed with screws were mobilized earlier than those with K-wire fixation.

CONCLUSIONS

Current evidence does not demonstrate a significantly superior method for the treatment of scaphoid nonunion. A multicenter randomized trial would be ideal but the large numbers that would be required may make this unrealistic. We recommend the continued reporting of series with specific assessments and outcome measures to optimize future comparisons in an attempt to determine the best management of scaphoid nonunion.

CLINICAL RELEVANCE

The use of bone grafts and the methods of their fixation for scaphoid nonunion are debated issues in hand and wrist surgery, with multiple methods employed. There is no current consensus on optimal treatment. A meta-analysis of proportions of available data from recent studies was deemed the most appropriate way to assimilate the available evidence with the view to inform surgeons of the optimal treatment according to the evidence base.

Arthroscopic Management of Scaphoid Nonunions

The difficulty in healing scaphoid nonunions is challenged further by the dynamic, unstable nature of the fracture-fragment interface. Recently, several investigators have introduced a minimally invasive technique for scaphoid nonunion repair, which has the advantages of minimal morbidity and accurate articular reduction, resulting in less postoperative stiffness and increased functional outcomes. However, failure to recognize the critical steps during minimally invasive surgery can result in incorrect treatment or limit any chances for successful bone repair. We reviewed the selected literature pertinent to arthroscopic techniques in the treatment of scaphoid nonunions. Furthermore, we presented a new arthroscopic approach that can be used in place of traditional formal open exposures in challenging cases of nonunion.

Arthroscopic management of chronic unstable scaphoid nonunions: effects on restoration of carpal alignment and recovery of wrist function

PURPOSE

The purpose of this study was to assess the effects of arthroscopically assisted reduction and osteosynthesis on restoration of carpal alignment and recovery of clinical wrist function in patients with unstable scaphoid nonunion.

METHODS

Thirty-six patients who underwent arthroscopically assisted osteosynthesis with or without bone grafting for unstable scaphoid nonunion between July 2006 and January 2012 were enrolled. The average time from injury to surgery was 51 ± 78.3 months. Radiographic and clinical evaluations were assessed on preoperative and postoperative days, and follow-up evaluation took place at a minimum of 24 months.

RESULTS

Union was achieved in 86% (31 of 36) of patients at a mean of 11 ± 2.7 weeks. Scaphoid axial length (SAL), lateral intrascaphoid angle (ISA), scapholunate angle (SLA), and reversed carpal height ratio (CHR) was significantly improved after surgery, and those correction ratios averaged 66% ± 46.8%, 74% ± 58.2%, 81% ± 59.8%%, and 94% ± 46%, respectively. The range of wrist motion was unchanged after surgery, but the grip strength improved from 74% ± 22.1% preoperatively to 89% ± 13.7% postoperatively compared with the contralateral side (P = .042). Mean Disabilities of the Arm, Shoulder, and Hand (DASH) and Patient-Related Wrist Evaluation (PRWE) scores improved significantly (P < .001) from 44 and 51 preoperatively to 13 and 23 postoperatively, respectively. The radiological parameters of the scaphoid and carpal alignment in patients who achieved bony union did not correlate with clinical wrist function.

CONCLUSIONS

Arthroscopic reduction and osteosynthesis of chronic unstable scaphoid nonunion is limited for restoration of normal carpal alignment but has positive effects on the recovery of clinical wrist function.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Graft choice in the management of unstable scaphoid nonunion: a systematic review

PURPOSE

To systematically compare outcomes between corticocancellous (CC) and cancellous-only (C-only) bone grafts for unstable scaphoid nonunions.

METHODS

The English-language literature was searched using PubMed, the Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Library with the following keywords: scaphoid, nonunion, malunion, unstable, collapse, humpback, dorsal intercalated segment instability, and deformity. Studies whose patient populations were characterized as possessing unstable scaphoid nonunion and/or collapse deformity or who met radiological definitions of such deformity were included. The union rate, interval to union, clinical assessments, strength, range of motion, correction of deformity, pain, and return to activity were analyzed.

RESULTS

Twenty-three studies published between the beginning of 1987 and the end of 2013 met the eligibility criteria and contained 604 patients. The union rate was statistically equivalent for C-only (95%) and CC grafts (92%). However, the frequency-weighted mean interval to union was significantly shorter for C-only (11 wk) than for CC grafts (16 wk). CC grafts were associated with a significantly higher frequency-weighted mean Mayo wrist score (86) than C-only grafts (80), whereas C-only grafting provided significantly greater improvement of wrist flexion. Of the 3 measures of carpal geometry analyzed, CC grafts significantly improved the scapholunate and radiolunate angles more than C-only grafts.

CONCLUSIONS

Based on retrospective data from uncontrolled studies, C-only grafts provide the shortest interval to union for unstable scaphoid nonunions. CC grafts are associated with consistent deformity correction and superior Mayo wrist scores.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Reliability and validity of carpal alignment measurements in evaluating deformities of scaphoid fractures

PURPOSE

Several radiographic carpal alignment indices are used to evaluate the deformities of scaphoid fractures. The purpose of this study was to determine the reliabilities and validities of radiographic carpal alignment indices commonly used to evaluate deformities of scaphoid fractures.

METHODS

Thirty-six patients with a scaphoid fracture were evaluated. Five carpal alignment indices were assessed on lateral plain radiographs, namely, scapholunate angle, radioscaphoid angle, radiolunate angle, radiocapitate angle, and capitolunate angle. Three examiners measured these radiographic indices at two sessions, and intraobserver and interobserver reliabilities were determined and expressed as intraclass correlation coefficients. Discriminant validities of radiographic carpal alignment indicies between injured and uninjured wrists were evaluated. For convergent validity testing, the correlation between the radiographic carpal alignment indices and intrascaphoid angles (ISAs) or height-to-length (HL) ratios on CT longitudinal scans was assessed. Further, carpal alignment indices after surgical reconstruction were compared to the Mayo wrist score.

RESULTS

Scapholunate and radiolunate angles had the highest reliabilities, and radiocapitate angle had the lowest. Radiolunate angle had the highest discriminant validity followed by scapholunate, and capitolunate angles. In convergent validity testing, scapholunate angles and radiolunate angles correlated with ISA angles, and radiolunate and capitolunate angles correlated with HL ratios. Only the radiolunate angles correlated with the Mayo wrist scores.

CONCLUSIONS

Among radiographic carpal alignment measures, radiolunate angle is the most reliable and valid carpal alignment index for evaluating deformities of scaphoid fractures. Scapholunate and capitolunate angles could be used as an alternative, but have less validity.

[Results of treatment of scaphoid nonunion with microvascularized bone grafts of the 1, 2 intercompartmental supraretinacular artery and osteosynthesis]

OBJECTIVE

To analyze the results of treatment of scaphoid nonunion with questionable viability of the proximal fragment, but without significant deformity or collapse, using a vascularized bone graft of 1,2 intercompartmental supraretinacular artery (1.2 ICSRA) and subsequent osteosynthesis.

MATERIAL AND METHOD

A retrospective study was performed on 10 male patients with a radiographic diagnosis of nonunion. Functionality, pain using Visual Analog Score (VAS), grip strength, patient satisfaction and reintroduction to working life, using QuickDASH and May specific wrist scales were assessed after the treatment. The integration of the graft was checked by radiography.

RESULTS

The mean follow-up was 31.4 months, and 90% of the questionnaires were satisfactory. The VAS decreased by 4.6 points and the flexor-extensor mobility gain was 5°. The total graft consolidation rate reached 40% in 5.5 months on average.

DISCUSSION

Several studies have demonstrated better results using vascularized bone graft versus non-vascularized. From the description by Zaidemberg in 1991, the vascularized graft with 1.2 ICSRA artery, distal radius, has been the most widely used for the treatment of scaphoid nonunion.

CONCLUSIONS

Our results are comparable with the literature reviewed, thus using vascular graft of the 1.2 ICSRA and osteosynthesis with Herbert-type screw, may be an alternative treatment for proximal scaphoid nonunion, without collapse or significant deformity.

Effect of wrist position on the measurement of carpal indices on the lateral radiograph

The purpose of this study was to find out whether the carpal indices measured on lateral radiographs with a slightly malpositioned wrist are the same as those measured in the true neutral position. Lateral radiographic views of 25 wrists were taken with 5° intervals from 20° of flexion to 20° of extension. Most carpal indices measured in the flexed or extended position were significantly different from the wrist in zero flexion-extension, except scapholunate angle at 5° of extension and scaphocapitate angle at 5° and 10° of flexion. Starting from the flexed position, there was an average of -4.0° change in radioscaphoid angle, -1.0° in scapholunate angle, -1.0° in scaphocapitate angle, +3.0° in radiolunate angle, and +2.0° in lunocapitate angle for each 5° of extension with linear trends. The results from this study suggest that even minimal degrees of flexion-extension can affect the measurements of carpal indices on lateral radiographs.

Scaphoid waist nonunion with humpback deformity treated without structural bone graft

PURPOSE

Conventional treatment of scaphoid nonunion with collapse deformity and bone loss involves the use of a structural corticocancellous bone graft. With internal screw fixation, we propose that length and alignment can be restored and maintained using only cancellous interposition graft.

METHODS

We describe 12 patients with established scaphoid waist nonunions. Average patient age was 22 years, all were male, and 8 cases involved the dominant wrist. Time from injury to treatment averaged 11 months. We performed open reduction through an anterior approach with correction of the deformity and placement of a distal to proximal screw. We then simply filled the resultant defect with cancellous autograft obtained from the ipsilateral distal radius. All patients underwent postoperative computed tomographic imaging to document union and degree of correction.

RESULTS

At a minimum 2-year follow-up, all patients had a united scaphoid with significant improvement in wrist extension compared with preoperative values. Grip strength also improved significantly. Disabilities of the Arm, Shoulder, and Hand scores at follow-up averaged 4 ± 3 (range, 0-9), the Mayo wrist score averaged 88 ± 6 (range, 80-100), and the average lateral intrascaphoid angle improved from 49° to 32° (normal, < 35°). Pain at follow-up as measured on a 10-point visual analog scale averaged 0.3 (range, 0-2).

CONCLUSIONS

With stable internal screw fixation, scaphoid waist nonunion with collapse and bone loss can be successfully treated using only cancellous bone graft. Advantages include marked simplification of surgical carpentry, the use of local autograft, and rapid incorporation of cancellous bone without compromise of scaphoid reduction and carpal alignment.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.