Chronic Scapholunate Ligament Injury: Techniques in Repair and Reconstruction

Impact of chronic wrist hypermobility on proprioception, strength, and functional performance in young adults

BACKGROUND

Chronic joint hypermobility has been attributed to repetitive ligamentous microtrauma, benign joint hypermobility syndrome (BJHS), or genetic connective tissue disorders that lead to pain and functional impairment, especially among females. Chronic wrist hypermobility (CWH) prevalence, etiology, and effects on proprioception, strength, and function have yet to be established.

PURPOSE

This pilot study aimed to determine the CWH prevalence among adults; its effects on proprioception, strength, and function; and whether these effects are gender based.

STUDY DESIGN

This was a quasi-experimental cross-sectional study.

METHODS

Ninety wrists (55 participants, mean age 27.46 years) with no wrist range of motion (ROM) restrictions or previous trauma for ≥6 months were screened for CWH based on an exploratory set of diagnostic criteria. Fifty-eight wrists (34 adults) were allocated to a CWH group, and 32 wrists (21 adults) were allocated to a healthy control group. Twenty-five CWH and 25 healthy control matched (gender, age, and handedness) participants were compared. Assessment included the active wrist joint position sense test, hand-held dynamometry for wrist extension and grip strength, and the patient-rated wrist evaluation for function. Testers were blinded to group allocation.

RESULTS

A 64.4% CWH prevalence existed among CWH participants, who were mostly asymptomatic females (74%). Frequent etiologic factors were midcarpal (96.5%) and scapholunate (39%) instabilities and BJHS (37%), which was higher among females (30%) than males (8%). Independent t-tests showed statistically significant (p < 0.05) group differences in wrist proprioception, wrist isometric extension, grip strength, and function with moderate-high (0.41-0.75) effect size. No significant gender differences existed in proprioception and function.

CONCLUSIONS

CWH is very prevalent among functional independent young adults with atraumatic midcarpal and intercarpal ligamentous laxities and BJHS. CWH prevails among women and adversely affects wrist proprioception, strength, and function. The study's specific CWH diagnostic criteria may be useful for clinicians to identify and timely manage impacted individuals by CWH.

Combined repair of scapholunate ligament (SL) and triangular fibrocartilage complex (TFCC) lesions in chronic trauma of the wrist: surgical treatment of 14 patients

PURPOSE

Injuries of the scapholunate ligament (SL) and of the triangular fibrocartilage complex (TFCC) represent the main ligament injuries of the traumatic wrist. A double injury of the SL and TFCC ligaments is quite common in the trauma setting, and clinical examination is fundamental. MRI allows to detection of a TFCC and SL ligament injury, but wrist arthroscopy is still the gold standard for diagnosis. We present the clinical results of the combined reconstruction of chronic scapholunate ligament and TFCC injury.

MATERIALS AND METHODS

Fourteen patients were treated at our hospital with a combined scapholunate ligament and TFCC complex repair. All patients were surgically treated by the same senior author, after a diagnostic arthroscopy that revealed a lesion of both structures. A comparison between the pre-operative and post-operative pain and function was carried out using VAS, Disability of Arm, Shoulder and Hand score (DASH) and Patient-Related Wrist/Hand Evaluation score (PRWHE). Wrist range of motion and strength were also compared following surgery.

RESULTS

All patients had a mean follow-up of 54 months. A statistically significant improvement was observed both with the reduction in pain (VAS from 8.9 to 5) and with the improvement of functionality scores (DASH from 63 to 40 and PRWHE from 70 to 57) and with the increase in ROM and strength. In only one patient (7%), because of pain and instability, a supplement operation was needed (Sauve-Kapandji procedure) 3 months after the initial surgery.

CONCLUSIONS

The simultaneous repair of the SL and TFCC complex has shown a good success rate in both decreasing pain and regaining functionality.

Clinical Outcomes of Arthroscopic-Assisted Volar Scapholunate Capsulodesis: A Case Series

Purpose  We have previously described arthroscopic-assisted volar scapholunate (SL) capsulodesis as an alternative technique for addressing volar SL interosseous ligament (SLIL) injuries. In this article, we report the outcomes of this procedure in a cohort of patients. Methods  Postoperative outcomes including range of motion, grip strength, visual analog scale (VAS) pain score, Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH), and Mayo Wrist Score were assessed through a prospective review of six patients in a single center who underwent this procedure. Results  Six patients (four male and two female) with a mean age of 43 ± 14 years were evaluated in the study. The mean duration of follow-up was 41 ± 17 weeks. Postoperative outcomes noted a reduction in VAS pain score from 8 before surgery to 0.7 postoperatively ( p  = 0.00004) and improvement in Mayo Wrist Score (42 preoperatively to 80 postoperatively; p  = 0.001), grip strength (86% of contralateral side; p  = 0.20), and flexion arc (81% of contralateral side; p  = 0.08). QuickDASH was 20 ± 8 and Patient-Rated Wrist Evaluation score was 13 ± 2 at the last clinical follow-up. There was an improvement in SL gap ( p  = 0.03), SL angle ( p  = 0.11), and radiolunate angle ( p  = 0.15) measurements postoperatively. Conclusions  The described arthroscopic-assisted volar SL capsulodesis in this study presents an alternative method to address volar SLIL pathology with positive short-term clinical outcomes. Clinical Relevance  Arthroscopic-assisted volar SL capsulodesis may be considered in the treatment algorithm for volar SLIL injuries.

Arthroscopy-Assisted Scapholunate Reconstruction With Internal Brace Augmentation

Various surgical techniques exist to repair or reconstruct complete scapholunate (SL) interosseous ligament tears, including capsulodesis, static or dynamic tenodesis, ligament reconstruction with tendon graft, bone-retinaculum-bone reconstruction, and the reduction and association of the scaphoid and lunate (RASL) procedure. The choice of surgical technique depends on arthroscopic assessment using the Geissler classification and European Wrist Arthroscopy Society staging of SL injury. This article describes arthroscopy-assisted extracapsular SL reconstruction using free tendon graft and internal brace augmentation for the treatment of unrepairable complete SL interosseous ligament tears.

InternalBrace for Intercarpal Ligament Reconstruction

SUMMARY

Intercarpal ligament injuries such as scapholunate and lunotriquetral tears are common causes of wrist pain. There is no shortage of surgical techniques to address these injuries, nor is there a lack of literature exploring this topic. However, research progress has not led to a consensus regarding the optimal management of subacute and chronic injuries without articular wear. The senior author (K.C.C.) has performed the spectrum of reconstructive techniques, including dorsal and volar approaches, tendon weaves, ligament tenodesis procedures, reduction and association procedures, and bone-ligament-bone techniques. In the absence of convincing, consistent outcomes, the authors began investigating a novel all-dorsal reconstructive technique using the Arthrex InternalBrace system. The complexity and unpredictable outcomes associated with traditional ligament tenodesis procedures led them to adopt the all-dorsal InternalBrace technique as their primary reconstructive approach. The authors have performed more than 20 procedures with this technique since 2019. In an average tourniquet time of under 60 minutes, they are able to achieve predictable carpal stabilization, pain relief, and restoration of motion. This is the preferred reconstructive approach of the senior author.

Comparison of Healing Effect Between Fibrin Gel Complex Bone Morphological Protein and Reconstituted Bone Xenograft After Reconstruction of Sports Ligament Injury

To study the effect of fibrin gel complex bone morphological protein (FG-BMP) and RBX on the healing of tendon-bone interface. 51 live rabbits were selected, and 51 rabbits were randomly divided into 3 groups: FG-BMP, RBX and control groups. Bilateral ACL reconstruction was performed in 51 rabbits, with different biomaterials injected at the tendon-bone interface, and none applied in the FG-BMP, RBX, and control groups. Material extraction, imaging examination, histological analysis, and biomechanical tests were conducted at 2 weeks after surgery, 6 weeks later, and 12 weeks after surgery, respectively. The tendon-interbone growth rate of rabbits using FG-BMP biomaterials and RBX biomaterials was significantly improved in the FG-BMP and RBX groups compared with the control group (P < 0.05). Histological results showed that all rabbits in the RBX group were surrounded by newborn bone tissue around the tendon-bone transplantation tendon and had a significantly greater number of newborn bone tissue than in the FG-BMP group (P < 0.05). The biomechanical test results showed that the two groups of FG-BMP biomaterials improved the maximum tension compared with the control group (P < 0.05), where the RBX tension, the difference was significant (P < 0.05), and the FG-BMP group although higher than the control group (P > 0.05). Conclusion: In the comparison of promoting tendon-bone interface healing, FG-BMP biomaterials and RBX biomaterials have significant results, especially RBX materials have obvious advantages in accelerating tendon-bone interface healing.

Outcomes after Bone-Ligament-Bone Intercarpal Ligament Reconstruction

BACKGROUND

Numerous surgical reconstructive techniques have been described for chronic scapholunate and lunotriquetral interosseous ligament instability.

METHODS

The authors retrospectively reviewed 16 consecutive patients who underwent bone-ligament-bone reconstruction for scapholunate or lunotriquetral intraosseous ligament predynamic and dynamic instability at a single tertiary care institution from 2013 to 2019. Clinical and radiographic outcomes, and complications, were recorded.

RESULTS

Eleven patients had bone-ligament-bone reconstruction for scapholunate ligament injury and five for lunotriquetral instability. Fourteen patients (87.5 percent) underwent diagnostic arthroscopy before bone-ligament-bone reconstruction, with nine of 14 having grade 3 and four of 14 having grade 4 injury. Capitohamate bone-ligament-bone grafts were used in nine patients (56 percent) and the graft was taken from Lister tubercle in seven (44 percent). The average age at surgery was 37 years. The average follow-up was 60.6 weeks. There were no significant differences between preoperative and postoperative radiographic parameters. Median postoperative wrist flexion was 45 degrees, and mean postoperative wrist extension was 53 degrees, which were significantly less than contralateral flexion (85 degrees; p < 0.0001) and extension (78 degrees; p < 0.0001). Thirty-eight percent of patients complained of persistent pain at final follow-up, and two patients (13 percent) underwent salvage procedures, both at approximately 6.5 months after the index reconstruction.

CONCLUSION

Short-term outcomes of bone-ligament-bone reconstruction for early-stage scapholunate and lunotriquetral ligament injuries reveal many patients with residual postoperative wrist pain and disability, and almost uniform limitations in flexion-extension motion.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Additive Manufacturing: The Next Generation of Scapholunate Ligament Reconstruction

Background  Ligament reconstruction, as a surgical method used to stabilize joints, requires significant strength and tissue anchoring to restore function. Historically, reconstructive materials have been fraught with problems from an inability to withstand normal physiological loads to difficulties in fabricating the complex organization structure of native tissue at the ligament-to-bone interface. In combination, these factors have prevented the successful realization of nonautograft reconstruction. Methods  A review of recent improvements in additive manufacturing techniques and biomaterials highlight possible options for ligament replacement. Description of Technique  In combination, three dimensional-printing and electrospinning have begun to provide for nonautograft options that can meet the physiological load and architectures of native tissues; however, a combination of manufacturing methods is needed to allow for bone-ligament enthesis. Hybrid biofabrication of bone-ligament tissue scaffolds, through the simultaneous deposition of disparate materials, offer significant advantages over fused manufacturing methods which lack efficient integration between bone and ligament materials. Results  In this review, we discuss the important chemical and biological properties of ligament enthesis and describe recent advancements in additive manufacturing to meet mechanical and biological requirements for a successful bone-ligament-bone interface. Conclusions  With continued advancement of additive manufacturing technologies and improved biomaterial properties, tissue engineered bone-ligament scaffolds may soon enter the clinical realm.

Arthroscopic Scapholunate Synthetic Ligamentoplasty

The scapholunate ligament is made of 3 portions: proximal, volar, and dorsal. The latter is the major stabilizer of the scapholunar pair, and its lesion is bound to cause a destabilization of the carpus, as well as scapholunar diastasis, dorsal intercalated segment instability, then eventually SLAC (i.e., scapholunate advanced collapse) wrist. The healing process of this ligament, either spontaneous or after primary repair with direct suture, is rarely observed and a significant number of patients are diagnosed only at a late stage, thus making an illusion of a maintained stability of the carpus first range. Management then consists of ligamentoplasty. Several open techniques are described to restore stability, but at the cost of a frequent and significant tightening of the wrist. We will introduce here an arthroscopic ligamentoplasty technique completed by a posterior capsulodesis.

MRI of the Wrist Ligaments

Technological advances in magnetic resonance imaging (MRI) have improved radiologists' ability to evaluate wrist ligaments. MRI interpretation often guides clinical management. This article aims to review the normal and pathologic appearance of intrinsic and extrinsic wrist ligaments with a focus on MRI. Variant anatomy, imaging pearls, and clinical significance are also discussed. Special attention is paid to key wrist ligaments that play a role in carpal stability.

Motion and Strength Analysis of 2-Tine Staple and K-Wire Fixation in Scapholunate Ligament Stabilization in a Cadaver Model

Purpose

Previous studies have demonstrated the benefits of 2- and 4-tine staple fixation in scapholunate interosseous ligament (SLIL) reconstruction, including improved rotational control and avoidance of the articular surface. This study compared scaphoid and lunate kinematics after SLIL fixation with traditional Kirschner wire (K-wire) fixation or 2-tine staple fixation.

Methods

Eight fresh frozen cadaver arms with normal scapholunate (SL) intervals were included. Infrared motion capture was used to assess kinematics between the scaphoid and lunate as the wrists were moved through a simulated dart-throw motion. Kinematic data were recorded for each wrist in 4 states: SLIL intact, SLIL sectioned, K-wire fixation across SL interval and scaphocapitate joint, and 2-tine Nitinol staple fixation across SL interval. Strength of the SL staple fixation was evaluated using an axial load machine to assess load to failure of the staple construct.

Results

Range of motion of the scaphoid and lunate with SLIL intact and SLIL sectioned were similar. K-wire fixation across the SL interval significantly decreased the overall wrist range of motion as well as scaphoid and lunate motion in all planes except for scaphoid flexion. Conversely, scaphoid and lunate motion after staple fixation was similar to that in normal wrists, except for a significant decrease in scaphoid extension. Under axial load simulating a ground-level fall, 3 of 8 arms demonstrated no failure, and none of the failures was due to direct failure of the 2-tine staple.

Conclusions

This study demonstrates 2-tine staple fixation across the SL interval is effective in providing initial stability and maintaining physiologic motion of the scaphoid and lunate compared with K-wire fixation after SLIL injury.

Clinical relevance

This study demonstrates an alternate technique for the stabilization of the SL interval in repair of acute SLIL injuries using 2-tine staple fixation, which maintains near physiologic motion of the scaphoid and lunate after SLIL injury.

The 50 most cited papers in chronic scapholunate reconstruction: a bibliometric analysis

PURPOSE

This study identifies the most impactful papers on scapholunate reconstruction and provides a quantitative assessment of the impact of these papers in order to inform future clinical practice, education, and research of this condition.

METHODS

The Scopus database was used in May 2020 to identify the 50 most cited clinical articles pertaining solely to chronic scapholunate reconstruction. Citation number and density, publication variables, and Altmetric Attention Scores (AASs) were collected and analyzed.

RESULTS

The top 50 articles on chronic scapholunate reconstruction produced 1,868 total citations, with an average of 37.36 ± 39.90 citations per article (range 7-196) and an average citation density of 2.44 ± 2.27. US-based publications (n = 20) and articles published in Journal of Hand Surgery (n = 24) were associated with significantly higher citation number and density (p < 0.01 - p = 0.018). In addition, sample size was positively correlated with citation density (rho = 0.312, p = 0.029). Fourteen articles were associated with an AAS (mean score = 4.07 ± 4.70). There was no significant association between AAS and citation number or density, but AAS did significantly predict citation density (coefficient = 0.378, 95% CI: [0.013-0.741], p = 0.043).

CONCLUSION

Numerous factors, such as journal of publication, location, and sample size, were significantly associated with citation number and/or citation density. Interestingly, AAS was predictive of, but not directly correlated with citation density, suggesting that the impact of scapholunate literature may not be adequately captured with a citation analysis.

Scapholunate Ligament Reconstruction With a Novel Technique for Passing Split Extensor Carpi Radialis Brevis Tendon Graft Through Bone Tunnels

We report 2 patients with acute scapholunate dissociation with static instability and wide scapholunate gapping. They underwent scapholunate reconstruction using a split extensor carpi radialis brevis (ECRB) tendon graft via a dorsal approach. This technique is adapted from the modified Brunelli tenodesis, utilizing a portion of the ECRB instead of a flexor carpi radialis tendon graft to reconstruct the scapholunate interosseous ligaments and dorsoradiotriquetral ligaments. The novel aspects of this technique include the use of a trifold plastic sheet of biaxially oriented polypropylene to facilitate the smooth passage of the 2 mm size ECRB tendon graft through the 2 mm bone tunnel. This enables us to avoid drilling larger holes in carpal bones with a relatively poor vascular supply and allows this technique to be utilized in patients with more delicately sized scaphoid and lunate bones. A 2 mm drill bit was used to create the scaphoid and lunate tunnels, which is smaller than that in the published literature. This trifold biaxially oriented polypropylene plastic sheath can be adapted to the use of many other techniques that require passing a tendon graft through a bone tunnel.

Management of chronic scapholunate ligament injury

Scapholunate ligament is the most commonly injured ligament in the wrist and requires accurate diagnosis and treatment. It presents with pain, stiffness and can lead to carpal instability as well as degenerative arthritis if left untreated, with subsequent loss of function and disability. There are several management options currently available but there is no consensus on how best to manage a wrist with chronic sequelae of scapholunate ligament injury. This review explores available evidence in the literature on optimal treatment options including non-operative and operative procedures, relevant surgical techniques and their associated outcomes. A summary of the current concepts in the management of Chronic Scapholunate ligament injury is presented.

Unplanned Reoperation After Surgery for Scapholunate Interosseous Ligament Insufficiency: A Retrospective Review of 316 Patients

Background: The purpose of this study was to identify factors associated with unplanned reoperation after surgery for scapholunate interosseous ligament (SLIL) insufficiency. Methods: Using Current Procedural Terminology (CPT) codes from 3 hand surgery centers across 2 metropolitan areas, we identified 316 patients undergoing surgery for SLIL insufficiency from 2000 to 2014. Medical records were manually reviewed to collect data on factors that might be associated with unplanned reoperation, including age, sex, tobacco use, occupation, acuity of treatment, and reconstruction method. Results: Thirty-eight patients (12%) had an unplanned reoperation; most of them (65%) were a secondary reconstruction or salvage procedure (eg, 6 proximal row carpectomies, 9 revision reconstruction, and 10 partial carpal arthrodeses), while 5 (13%) were for unplanned screw removal. The median time between the index and second surgery was 16 months (range, 2-97 months). The type of index procedure was not associated with reoperation. The only factor associated with reoperation was cigarette smoking, and this association persisted when looking specifically at reoperations for revision or salvage. Conclusions: Patients should be counseled that smoking is associated with reoperation after SLIL surgery. Smoking cessation or decreasing nicotine usage may be beneficial prior to surgery. With the numbers available, there was no association between surgical technique and reoperation.

Pregnancy-Related Ligamentous Laxity Mimicking Dynamic Scapholunate Instability: A Case Report

CASE

A 29-year-old woman presented with spontaneous, isolated, total palmar scaphoid subluxation in the left hand approximately 6 weeks postpartum. She had a positive Watson scaphoid shift test, with an easily subluxable and reducible scaphoid unilaterally. She was diagnosed with scapholunate ligamentous laxity with dynamic instability. Approximately 4 months after stopping lactation, she had complete resolution of the scapholunate subluxation; there was no recurrence of symptoms over the next 5 years of follow-up.

CONCLUSION

Women can have manifestations of pregnancy and lactation-related ligamentous laxity, including scapholunate instability, which may spontaneously resolve upon cessation of lactation.

Update on operative treatment of scapholunate (SL) instability for radiologists: part 1-SL ligament repair, dorsal capsulodesis and SL ligament reconstruction

Scapholunate instability is the most common form of carpal instability. Imaging (especially radiography) plays an important role in the staging, management and post-operative follow-up of scapholunate (SL) instability. The goals of this article are to review the pre-operative staging of SL instability, the surgical options for repair and reconstruction of the SL ligament, along with the normal postoperative imaging findings as well as complications associated with these surgical options.

Evaluation of the performance of three tenodesis techniques for the treatment of scapholunate instability: flexion-extension and radial-ulnar deviation

Chronic scapholunate ligament (SL) injuries are difficult to treat and can lead to wrist dysfunction. Whilst several tendon reconstruction techniques have been employed in the management of SL instability, SL gap reappearance after surgery has been reported. Using a finite element model and cadaveric study data, we investigated the performance of the Corella, scapholunate axis (SLAM) and modified Brunelli tenodesis (MBT) techniques. Scapholunate dorsal and volar gap and angle were obtained following virtual surgery undertaken using each of the three reconstruction methods with the wrist positioned in flexion, extension, ulnar deviation and radial deviation, in addition to the ulnar-deviated clenched fist and neutral positions. From the study, it was found that, following simulated scapholunate interosseous ligament rupture, the Corella technique was better able to restore the SL gap and angle close to the intact ligament for all wrist positions investigated, followed by SLAM and MBT. The results suggest that for the tendon reconstruction techniques, the use of multiple junction points between scaphoid and lunate may be of benefit.

Graphical abstract

Arthroscopic Scapholunate Ligament Reconstruction, Volar and Dorsal Reconstruction

Arthroscopic scapholunate volar and dorsal ligament reconstruction achieves an anatomic reconstruction, avoids an open approach and capsular detachment, and provides a strong construct for early mobilization. Clinical results are discussed. Detailed "surgical tips" and technical modifications are provided.

Dorsal Scaphoid Subluxation on Sagittal Magnetic Resonance Imaging as a Marker for Scapholunate Ligament Tear

PURPOSE

To evaluate the diagnostic utility of scaphoid dorsal subluxation on magnetic resonance imaging (MRI) as a predictor of scapholunate interosseous ligament (SLIL) tears and compare this with radiographic findings.

METHODS

Thirty-six MRIs were retrospectively reviewed: 18 with known operative findings of complete Geissler IV SLIL tears that were surgically repaired, and 18 MRIs performed for ulnar-sided wrist pain but no SLIL tear. Dorsal subluxation of the scaphoid was measured on the sagittal MRI cut, which demonstrated the maximum subluxation. Independent samples t tests were used to compare radiographic measurements of scapholunate (SL) gap, SL angle, and capitolunate/third metacarpal-lunate angles between the SLIL tear and the control groups and to compare radiographic measurements between wrists that had dorsal subluxation of the scaphoid and wrists that did not have dorsal subluxation. Interrater reliability of subluxation measurements on lateral radiographs and on MRI were calculated using kappa coefficients.

RESULTS

Thirteen of 18 wrists with complete SLIL tears had greater than 10% dorsal subluxation of the scaphoid relative to the scaphoid facet. Average subluxation in this group was 34%. Four of 18 wrists with known SLIL tears had no subluxation. No wrists without SLIL tears (control group) had dorsal subluxation. The SL angle, capitolunate/third metacarpal-lunate angle and SL gap were greater in wrists that had dorsal subluxation of the scaphoid on MRI. Interrater reliability of measurements of dorsal subluxation of the scaphoid was superior on MRI than on lateral x-ray.

CONCLUSIONS

An MRI demonstration of dorsal subluxation of the scaphoid, of as little as 10%, as a predictor of SLIL tear had a sensitivity of 72% and a specificity of 100%. The high positive predictive value indicates that the presence of dorsal subluxation accurately predicts SLIL tear.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Biomechanical Properties of First Dorsal Extensor Compartment Regarding Adequacy as a Bone-Ligament-Bone Graft

Bone-ligament-bone grafts for reconstruction of the scapholunate ligament are a valuable tool to prevent disease progression to carpal collapse. Locally available grafts do not require an additional donor site. The first extensor compartment was evaluated biomechanically regarding its possible use as an autograft.

METHODS

Twelve native fresh-frozen, human cadaver specimens were tested by applying axial tension in a Zwick Roell machine. Load to failure, transplant elongation, and bony avulsion were recorded. The load to failure was quantitated in newtons (N) and the displacement in length (millimeters). Parameters were set at distinct points as start of tension, 1 mm stretch and 1.5 mm dissociation, failure and complete tear, and were evaluated under magnified visual control. Although actual failure occurred at higher tension, functional failure was defined at a stretch of 1.5 mm.

RESULTS

Mean load at 1 mm elongation was 44.1 ± 28 N and at 1.5 mm elongation 57.5 ± 42 N. Failure occurred at 111 ± 83.1 N. No avulsion of the bony insertion was observed. Half the transplants failed in the central part of the ligament, while the rest failed near the insertion but not at the insertion itself. Analysis of tension strength displayed a wide range from 3.8 to 83.7 N/mm at a mean of 33.4 ± 28.4 N/mm.

CONCLUSIONS

The biomechanical tensile properties of the first dorsal extensor compartment are similar to those of the dorsal part of the scapholunate ligament. A transplant with a larger bone stock and a longer ligament may display an advantage, as insertion is possible in the dorsal, easily accessible part of the carpal bones rather than in the arête-like region adjacent to the insertion of the scapholunate ligament. In this study, 1.5 mm lengthening of the bone-ligament-bone transplant was defined as clinical failure, as such elongation will cause severe gapping and is considered as failure of the transplant.