Imaging of four-corner fusion (SLAC arthrodesis) of the wrist with 64-slice computed tomography

Lunocapitate versus four-corner fusion in scapholunate or scaphoid nonunion advanced collapse: a randomized controlled trial

This pragmatic randomized controlled trial compared lunocapitate fusion (LCF) and four-corner fusion (4CF) for scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC) in 64 patients. The primary outcome was change in grip strength from preoperative to 1 year postoperatively. The secondary outcomes were Disability of the Hand, Arm, and Shoulder score, Patient Rated Wrist Evaluation score, EuroQol-5D-3L, range of motion, key pinch strength and complications 12 months postoperatively. Grip strength improved only to a small extent and there was no difference between the groups. No differences were found in the secondary outcomes. In conclusion, LCF is not inferior to 4CF regarding strength, range of motion or patient-reported outcome measures.Level of evidence: I.

Surgical fixation techniques in four-corner fusion of the wrist: a systematic review of 1103 cases

BACKGROUND

Four-corner fusion (4CF) is a known treatment option for degenerative wrist conditions. Different techniques may be used and there is no general consensus on best implant. As such, it was the purpose of the current systematic review to compare fusion rates and outcomes depending on the fixation technique.

METHODS

The systematic review was registered in the international prospective register of systematic reviews (PROSPERO): CRD42020164301. It followed the PRISMA guidelines. Original articles were screened using the following databases: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and Web of Science Core Collection. Studies reporting on outcome for 4CF surgery were included. Studies with a minimum Level IV of evidence were considered eligible. Quality assessment was performed using the Methodological Index for Non-Randomized Studies (MINORS) criteria.

RESULTS

A total of 29 studies met the inclusion criteria, for a total of 1103 wrists. The mean age was 41.8 years (range 19-83). Mean follow-up overall was 43.5 months (range 24-146 months). Reported fusion weighted rates were >90% and did not differ significantly between techniques. Reoperations due to different reasons occurred in 135 (12%) of all 1103. There was significant data heterogeneity regarding fusion rates (I² = 70%). Inconsistency and heterogeneity in data reporting did not allow meta-analysis with direct data pooling and comparison of subgroups.

CONCLUSIONS

Satisfactory fusion rates (over 90%) can be achieved independent of the fixation technique used in 4-corner arthrodesis. Due to the high data heterogeneity and reporting inconsistency across studies, no statements regarding PROMs, ROM or grip strength can be made.

LEVEL OF EVIDENCE

Systematic Review of Level IV Studies.

Four-Corner Arthrodesis With Differing Methods of Osteosynthesis: A Systematic Review

PURPOSE

The purpose of this study was to compare the union rates and clinical outcomes of 4-corner arthrodesis with different methods of osteosynthesis.

METHODS

A systematic review of studies published in Ovid, Medline, Embase, and PubMed was conducted. Primary studies that reported clinical and radiographic results following 4-corner arthrodesis for scapholunate advanced collapse (SLAC), scaphoid nonunion advanced collapse (SNAC), or other types of wrist arthritis in human subjects were eligible. Biomechanical or cadaveric studies, case reports, studies that did not define and report a radiographic union rate, reviews and technical articles, studies that did not report the method of osteosynthesis, and studies that used multiple methods of osteosynthesis, but did not separate results for individual methods of osteosynthesis were excluded. Radiographic union rate, range of motion, and grip strength were analyzed.

RESULTS

We identified and reviewed 291 full texts, selecting 57 studies for coding. The radiographic union rate did not significantly differ between studies using K-wire, screw, staple, nonlocking plate, metal locking plate, and radiolucent locking plate osteosynthesis. Fixation method significantly affected flexion, but pairwise comparison did not reveal any significant differences between individual groups. Grip strength as a percentage of the contralateral limb was significantly lower in studies with metal locking plate fixation compared to K-wire fixation (63.2% vs 82.6%). There were no other statistically significant differences between groups with respect to flexion, extension, radial deviation, ulnar deviation, and grip strength.

CONCLUSIONS

All methods of osteosynthesis result in similar union rates, with no significant differences between methods. While there are some significant differences in range of motion and grip strength, these differences are unlikely to be clinically relevant.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

3D analysis of Osteosyntheses material using semi-automated CT segmentation: a case series of a 4 corner fusion plate

Backround

Scaphoidectomy and midcarpal fusion can be performed using traditional fixation methods like K-wires, staples, screws or different dorsal (non)locking arthrodesis systems. The aim of this study is to test the Aptus four corner locking plate and to compare the clinical findings to the data revealed by CT scans and semi-automated segmentation.

Methods

This is a retrospective review of eleven patients suffering from scapholunate advanced collapse (SLAC) or scaphoid non-union advanced collapse (SNAC) wrist, who received a four corner fusion between August 2011 and July 2014. The clinical evaluation consisted of measuring the range of motion (ROM), strength and pain on a visual analogue scale (VAS). Additionally, the Disabilities of the Arm, Shoulder and Hand (QuickDASH) and the Mayo Wrist Score were assessed. A computerized tomography (CT) of the wrist was obtained six weeks postoperatively. After semi-automated segmentation of the CT scans, the models were post processed and surveyed.

Results

During the six-month follow-up mean range of motion (ROM) of the operated wrist was 60°, consisting of 30° extension and 30° flexion. While pain levels decreased significantly, 54% of grip strength and 89% of pinch strength were preserved compared to the contralateral healthy wrist. Union could be detected in all CT scans of the wrist. While X-ray pictures obtained postoperatively revealed no pathology, two user related technical complications were found through the 3D analysis, which correlated to the clinical outcome.

Conclusion

Due to semi-automated segmentation and 3D analysis it has been proved that the plate design can keep up to the manufacturers’ promises. Over all, this case series confirmed that the plate can compete with the coexisting techniques concerning clinical outcome, union and complication rate.

The rate of successful four-corner arthrodesis with a locking, dorsal circular polyether-ether-ketone (PEEK-Optima) plate

The purpose of this study is to evaluate the rate of union after four-corner arthrodesis with a locking, dorsal circular plate comprised of polyether-ether-ketone. A retrospective review was conducted of all patients who underwent four-corner arthrodesis with a locking, dorsal circular plate at our institution from January 2005 to May 2009. The primary outcome measure was radiographic and clinical union. During the study period, 26 consecutive wrists underwent four-corner arthrodesis with a locking, dorsal circular plate. Twenty-three wrists were included. The mean clinical follow-up was 16 months (range 3-37). Union was achieved in 22 of 23 wrists at a mean time of 3 months (range 1-12). There was one partial union that underwent successful revision arthrodesis. In summary, four-corner fusion with a polyether-ether-ketone locking, dorsal circular plate results in high union rates. The use of a radiolucent plate allows for more accurate assessment of union with the biomechanical advantages of a fixed angle construct.

OUTCOMES OF FOUR-CORNER ARTHRODESIS USING THE HUBCAPTM CIRCULAR PLATE

We present results of four-corner carpal arthrodesis with the Acumed® HubcapTM circular plate performed at our unit. Eight patients underwent eight procedures over five years, for scapholunate advanced collapse (five wrists) and scaphoid non-union advanced collapse (three wrists). Outcomes included range of motion, quickDASH scores, and visual analogue scores for satisfaction. At final follow-up, mean flexion-extension arc was 56°, mean radial-ulnar deviation 29° and mean quickDASH score was 23/100. Mean score for satisfaction was 7.7/10 (77%). Seven out of eight (87.5%) patients said they would have it done again, and would also recommend it to others. Radiological union was achieved in all cases. One screw broke in one arthrodesis without causing symptoms. The functional outcomes with our use of the HubcapTM are comparable to those reported in literature to date with other circular plates (e.g. Spider plate). There were no non-unions, which is the main reported complication with these plates.

Four-corner arthrodesis with a locking, dorsal circular polyether-ether-ketone (PEEK-Optima) plate

Scaphoidectomy and 4-corner arthrodesis can be a successful salvage procedure for scaphoid nonunion advanced collapse and scapholunate advanced collapse. Traditional methods of fixation include Kirschner wires, staples, and/or headless compression screws. Nonlocking, dorsal circular plates, manufactured from stainless steel, have been advocated to allow early wrist range of motion and improved union rates. However, the reported union rates have been variable and inconsistent. This wide results have been attributed to the difficulty in assessing union with plain film radiograph due to the radio-opaque plate. Recently, a locking, dorsal circular plate, comprised of a radiolucent polyether-ether-ketone (PEEK-Optima), has been introduced with the additional benefit of providing a fixed-angle construct and allowing a more accurate assessment of bone union with plain film imaging studies.

Reliability of the 8 Week Time Point for Single Assessment of Midcarpal Fusion by CT Scan

High rates of nonunion have recently been reported for midcarpal fusions. Due to curvature and overlap of carpal interfaces, two dimensional films are not reliable in determining union of a midcarpal fusion. Computed tomography is the most reliable radiographic method of evaluating osseous union. Initiating motion as soon as fusion has occurred is a priority with the goal of maximizing final range. Cost control in healthcare makes obtaining serial scans unreasonable. The single optimal time point for a computed tomography scan to determine union of a midcarpal fusion remains to be determined. A prospective protocol selected 8 weeks post operative as the point in time to obtain the single determining scan. Forty-six consecutive midcarpal fusions with scaphoidectomy were retrospectively analyzed for the reliability of this time point. All fusions had achieved union by 8 weeks and only this one scan was clinically necessary to advance the patients on to full range of motion without a splint at that time.

Clinical outcome of rearthrodesis in cases of non-union following four-corner fusion

PURPOSE

Four-corner fusion is a proven treatment option for degenerative arthritis of the wrist (SLAC/SNAC); however, in some cases, non-union occurs. The purpose of this study was to evaluate the clinical outcome of rearthrodesis in cases of non-union following four-corner fusion. Furthermore, the goal was to identify the cause of non-union and the location of pseudarthrosis within the fusion.

METHODS

Seven patients (5 males, 2 females) who experienced pseudarthrosis following a four-corner fusion procedure and subsequently elected a rearthrodesis procedure were clinically and radiologically examined. The average age was 58 years (range 48-71 years). Average follow-up after rearthrodesis was 27 months (range 4-60 months). All patients experienced persistent wrist pain and non-union was diagnosed via radiography or CT scan. Range of motion, grip strength, the Modified Mayo Wrist score, and the DASH score were evaluated. The level of pain was determined by using a visual analogue scale. Patients were also asked whether they were satisfied with the procedure and if they would elect it again.

RESULTS

In all patients, the rearthrodesis procedure led to proper bone consolidation, which was verified by radiological examination. Due to persistent wrist pain, one patient required additional procedures (denervation, wrist arthroscopy). In four cases, the location of pseudarthrosis occurred between the triquetrum and hamate. In three cases, the location of pseudoarthrosis was between the capitate and lunate and, additionally, between the triquetrum and hamate. The average DASH score value was 38 and the average Modified Mayo Wrist score was 66. Grip strength was reduced to 85 percent of the contralateral, unaffected side. Three patients indicated that they are dissatisfied with the results and would not elect the procedure again.

CONCLUSIONS

The most frequent location of pseudarthrosis was between the triquetrum and the hamate, which was caused by incomplete cartilage debridement. Proper bone consolidation could be attained by means of rearthrodesis in cases of non-union following four-corner fusion. However, clinical results remain only moderate.

First experiences with the use of intraoperative 3D-RX for wrist surgery

With the use of conventional C-arm fluoroscopy for hand surgery, suboptimal positioning of implants, K-wires, insufficient reconstructions and joint incongruities frequently remain unrevealed We prospectively compared the performance of the surgeon interpreted from conventional methods (2D fluoroscopy and direct visual and physical inspection) versus 3D imaging as well as the occurrence of revision surgeries based on post-op radiological findings. Twenty-four intraoperative findings based on 2D fluoroscopy and findings on direct visual and physical inspections were compared with intraoperatively acquired 3D-RX scans by means of a questionnaire. Moreover, record was kept of revision surgery (minimal three months follow up) for all patients treated with the aid of 3D-RX. A clear difference in findings was observed between the performance based on fluoroscopy and direct visual and physical inspection and that based on intraoperative 3D-RX for hand surgery (p < 0.05). Post-operative radiological examinations revealed that none of the 56 patients treated with the aid of 3D-RX needed revision surgery. Intraoperative 3D-RX provides information for the hand surgeon that is additional to the information acquired with conventional fluoroscopy. Intraoperative 3D-RX provides well defined images of the positioning of osteosynthesis material, of the spatial orientation of carpals, and of reconstruction of the wrist joint.

Internal headless compression screw method for 4-corner fusion

Midcarpal fusion and scaphoidectomy, also referred to as 4 corner fusion, is a common treatment for post-traumatic wrist arthritis, either scapholunate advanced collapse or scaphoid nonunion advanced collapse. Historically fixation for the fusion mass was performed with Kirschner wires. Bone graft was sometimes taken from the discarded scaphoid. More recently, articles have focused on the method of fixation and its potential role in causing high nonunion rates or specific complications. This article offers readers a reliable technique for midcarpal fusion designed to minimize both nonunion and hardware related complications.

Detection of in vivo dynamic 3-D motion patterns in the wrist joint

We present a method for measurement dynamic in vivo carpal motion patterns. The method consists of a 4-D rotational X-ray (RX) with improved image quality and image processing for accurate detection in vivo wrist motion measurements. Dynamic 3-D imaging yields a number of volume reconstructions of the wrist at different phases of its cyclic motion. Next, the carpal reconstructions are registered to their static acquired and segmented counterpart in all phases. With this information, the relation between the applied motion and carpal kinematic behavior is acquired, i.e., the motion patterns. We investigated the precision of the image acquisition and processing and tested it on three healthy subjects. The precision of the image acquisition and image processing is in the range of submillimeters and subdegrees, respectively, which is better than existing systems and sufficient for clinical investigations. Reproducibility measurements show some more deviation ( > 1 degrees). This method was tested on four human volunteers and agrees for the greater part with previously done invasive and nondynamic measurements. In vivo motion pattern measurement with 4-D-RX imaging and processing is accurate and noninvasive. The motion patterns can reveal disorders that could not have been detected in either video fluoroscopy, computed tomography, or MRI.