Scapholunate ligament reconstruction using a bone-retinaculum-bone autograft: a biomechanic and histologic study

Dorsal Scapholunate Ligament Reconstruction by Using Palmaris Longus Tendon Graft in Chronic Static Scapholunate Dissociations: Does It Yield Favorable Radiographic and Functional Results?

Background  Scapholunate (SL) instability is the most common dissociative carpal instability, and the most frequent cause of wrist osteoarthritis (OA), termed as scapholunate advanced collapse (SLAC). The aim of this study was to present the mid-term clinical and radiographic results of dorsal SL ligament reconstruction by utilizing free palmaris longus tendon graft in patients with symptomatic, chronic, static SL dissociation; while assessing the safety and efficacy of this technique, Materials and Methods  In total, 42 patients with a mean age of 44.1 (range 26-53) and mean follow-up duration of 69.4 months (range 60-72) with a diagnosis of chronic, static, and reducible SL instabilities with no chondral damage were enrolled. They all underwent dorsal SL ligament reconstruction with the exam same technique. Results  At the last follow-up, patients' mean preoperative SL gap improved from 4.7 (range 4-6) to 2.1 (range 2-3), as did SLA from 84 degrees (range 67-101 degrees) to 66 degrees (range 49-72 degrees)( p <0.001 for both). Preoperative mean VAS (visual analog score), DASH (Disabilities of the Arm, Shoulder and Hand), Mayo wrist scores and SF-36 scores showed significant improvements in the last follow-up visit ( p <0.001, for all). No major complications were acquired in either of the patients. Conclusion  Dorsal SL ligament reconstruction by using free PL tendon graft was detected to provide successful restoration of the normal carpal alignment together with SL joint stability. This procedure, by significantly reducing pain and improving grip strength was detected to yield significantly improved clinical and functional outcomes, together with high patient satisfaction indicated by improved health-related quality of life (HRQOL) scores. Level of Evidence  IV.

Current Concepts in Scapholunate Instability Without Arthritic Changes

Scapholunate instability (SLI) is the most common carpal instability described. SLI leads to a degenerative arthritic pattern known as scapholunate advanced collapse (SLAC). Diagnosis of SLI can be challenging in pre-dynamic and dynamic stages. CT arthrogram, MR arthrogram and dynamic fluoroscopy are helpful in diagnosis while arthroscopy remains the gold standard. SLI is a multi-ligament injury, which involves not only the scapholunate interosseous ligament (SLIL) but also the extrinsic carpal ligaments. Hence, it is better described as an injury compromising the 'dorsal scapholunate(dSLL) complex'. A repair can be attempted for acute SLI presenting within 6 weeks of injury. Reconstruction is the mainstay of treatment for chronic SLI without degenerative changes. Multiple repair techniques have been described which include capsulodesis and tenodesis procedures. The clinical outcomes of the techniques have improved over the years. However, a common problem of all these techniques is the lack of long-term data on the outcomes and deteriorating radiological parameters over time. SLI staging is an important factor to be considered in choosing the reconstruction techniques for a better outcome. Currently, there is a trend towards more biological and less invasive techniques. Regardless of the technique, it is important to preserve the nerve supply of the dorsal capsuloligamentous structures of the wrist. Arthroscopic techniques being minimally invasive have the advantage of less collateral damage to the capsuloligamentous structures. Rehabilitation involves a team approach where a protected dart thrower's motion is allowed after a period of immobilization. Strengthening SL-friendly muscles and inhibiting SL-unfriendly muscles is a key principle in rehabilitation.

Ligamentization and Remnant Integration: Review and Analysis of Current Evidence and Implications for Scapholunate Reconstruction

Background  Scapholunate interosseous ligament injuries are common but remain a therapeutic challenge. Current treatment modalities prioritize restoration of normal anatomy with reconstruction where appropriate. To date no reconstructive technique has been described that discusses the potential benefit of preservation of the scapholunate ligament remnant. Little is known about the "ligamentization" of grafts within the wrist. However, a growing body of knee literature suggests that remnant sparing may confer some benefit. In the absence of wrist specific studies, this literature must guide areas for potential augmentation of current surgical practices. Objective  The purpose of this study was to perform a review of the process of ligamentization and a systematic review of the current literature on the possible role of ligament sparring and its effect on ligamentization. Methods  A systematic search of the literature was performed to identify all the studies related to remnant sparing and the ligamentization of reconstructed tendons, regardless of graft type or joint involved from MEDLINE, EMBASE, and PubMed until February 1, 2016 using the following keywords: ligamentization, graft, remodelling, reconstruction, biomechan*, histolo∗, scapholunate ligament. Each selected study was evaluated for methodological quality and risk of bias according to a modified Systematic Review Center for Laboratory Animal Experimentation criteria. Conclusions  The available literature suggests that ligament sparring demonstrated a trend toward improvements in vascularity, mechanoreceptors, and biomechanics that lessens in significance over time. Clinical Relevance  This review suggests that remnant sparing may be one way to improve outcomes of scapholunate ligament reconstructive surgery. Level of Evidence  This is a level I/II, review study.

Autologous Osteoligamentous Reconstruction of Scaphoid Proximal Pole With Metatarsal Head and Collateral Ligament: Cadaver Anatomic Description of Novel Surgical Technique

Background: Historically, scaphoid nonunion has been surgically treated with vascularized bone graft taken from multiple different anatomic sites. However, none of these grafts fully recapitulate the unique osteoligamentous anatomy of the proximal pole of the scaphoid and the attachment of the scapholunate ligament (SLIL). We studied the anatomy of the vascularized second metatarsal head with its lateral collateral ligament as a potential novel treatment of proximal pole scaphoid nonunion with collapse. Methods: Scaphoids and second metatarsal heads were harvested from bilateral upper and lower extremities of 18 fresh frozen cadavers (10 male, 8 female) for a total of 36 scaphoids and 36 second metatarsal heads. The ipsilateral second metatarsal head was harvested with its lateral collateral ligament and its blood supply from the second dorsal metatarsal artery (SDMA). Measurements of the scaphoid, the SLIL, the second metatarsal head, and lateral collateral ligaments were compared to matched limbs from the same cadaver. Results: The anatomic dimensions of the second metatarsal head with its lateral collateral ligament are similar to the scaphoid proximal pole and the SLIL in matched cadaveric specimen. Conclusions: This anatomic cadaver study reveals that the second metatarsal head with its associated lateral collateral ligament is a well-matched donor to reconstruct the proximal pole of the scaphoid and SLIL. This anatomic similarity may be well suited to treat nonunion of the scaphoid proximal pole with or without avascular necrosis with simultaneous reconstruction of the SLIL. The authors describe a technique of vascularized reconstruction of the osteoligamentous proximal pole of the scaphoid with its attached SLIL utilizing autologous second metatarsal head with its attached lateral collateral ligament. Based on this cadaver study, this technique merits consideration.

Radio-luno-triquetral bone-ligament transfer as an additional stabilizer in scapholunate-instability

INTRODUCTION

Reconstruction of the scapho-lunate (SL) ligament is still challenging. Many different techniques, such as capsulodesis, tendon graft and bone-ligament-bone graft have been described to stabilize reducible SL dissociation. If primary ligament repair alone is not possible, an additional stabilizer is needed to achieve scapho-lunate stability. A new local bone-ligament transfer using half of the radio-luno-triquetral ligament is performed. The direction of traction of the transposed ligament is very similar to the original ligament. Ideal tension can be attained by fixation of the bone block at the dorsal ridge of the scaphoid. The biomechanical stability of this bone-ligament transfer shall be examined biomechanically.

MATERIAL AND METHODS

Computed tomography imaging was performed using eight cadaveric forearms with a defined position of the wrist. Axial load was accomplished with tension springs attached to the extensor and flexor tendons. Three series ([a] native, [b] divided SL ligament and [c]) after reconstruction with bone-ligament transfer] were reconstructed three-dimensionally to determine the angles between radius, scaphoid and lunate. The radial distal part including a bone fragment of the radio-luno-triquetral ligament was transferred from its insertion at the distal edge of the radius to be attached to the dorsal ridge of the scaphoid.

RESULTS

SL gap was widened after its transection. Average SL distance was 6.6 ± 1.6 mm. After ligament reconstruction, the gap could be narrowed significantly to 4.2 mm (± 0.7 mm). The movement of the scaphoid and lunate showed significant changes, especially in wrist flexion, fist closure and radial deviation. These deviations could be corrected by the bone ligament transfer.

CONCLUSION

Reconstruction of a transected SL ligament with a bone-ligament transfer from the radio-luno-triquetral ligament reduces SL dissociation under axial load. The described surgical technique causes low donor-side morbidity and can be considered in addition to improve stability if SL ligament suture alone does not appear sufficient.

LEVEL OF EVIDENCE

Level II, therapeutic investigating experimental study.

Internal Bracing Augmentation for Scapholunate Interosseous Ligament Repair: A Cadaveric Biomechanical Study

PURPOSE

Internal bracing (IB) is an augmentation method using high-strength nonabsorbable tape. This study compared scapholunate interosseous ligament (SLIL) repair alone, SLIL repair with IB augmentation (RIBA), and native intact SLIL (NIS) in a biomechanical cadaveric model.

METHODS

We used 21 specimens of fresh-frozen wrists in this study (7 matched pairs, SLIL repair-only and SLIL RIBA groups; and 7 independent fresh-frozen wrists, NIS group). In the SLIL RIBA group, augmentation using IB was performed after the repair. The specimens were preloaded and cyclically loaded in tension. Maximum extension and hysteresis were measured in all specimens. The specimens were subsequently tested for load to failure. Failure load (yield point load, mean ultimate load, and load at clinical failure) and linear stiffness were calculated.

RESULTS

In cyclic tensile testing, RIBA showed lower maximum extension and lower hysteresis than repair alone. In load to failure testing, the yield point load was statistically higher in the RIBA (59.3 N) group than in the repair-only (30.4 N) group but showed no significant difference compared with the NIS (90.7 N) groups. Moreover, the RIBA (98.5 N) group showed higher and lower mean ultimate loads than the repair-only (37.7 N) and NIS (211.8 N) groups, respectively. Load at clinical failure was higher with RIBA than with repair alone (3-mm extension: 70.0 vs 26.4 N; 4-mm extension: 84.1 vs 33.4 N). Repair alone and RIBA had comparable linear stiffness (38.2 vs 44.1 N/mm).

CONCLUSIONS

Although SLIL RIBA did not recreate biomechanical properties equivalent to those of NIS, it demonstrated a significantly higher strength than repair alone.

CLINICAL RELEVANCE

Repair with IB augmentation could serve as a novel surgical technique that enhances SLIL direct repair through biomechanical support.

Scapholunate kinematics after flexible anchor repair

The scapholunate joint is one of the keystones of the wrist kinematics, and its study is difficult due to the carpal bones size and the richness of surrounding ligaments. We propose a new method of quantitative assessment of scapholunate kinematics through bone motion tracking in order to investigate scapholunate ligament lesion as well as repair techniques. On 6 intact wrists, steel beads were inserted into the bones of interest to track their motions. Experimental set up allowed wrist flexion extension and radio-ulnar deviation motions. Low-dose bi-planar radiographs were performed each 10° of movement for different configurations: 1) intact wrist, 2) scapholunate ligament division, 3) repair by soft anchors at the posterior then 4) anterior part. Beads' 3D coordinates were computed at each position from biplanar X-Rays, allowing accurate registration of each wrist bone. The Monte Carlo sensitivity study showed accuracy between 0.2° and 1.6 ° for the scaphoid and the lunate in motions studied. The maximum flexion-extension range of motion of the scaphoid significantly decreased after anterior repair from 73° in injured wrist to 62.7°. The proposed protocol appears robust, and the tracking allowed to quantify the anchor's influence on the wrist kinematics.

Additively Manufactured Multiphasic Bone-Ligament-Bone Scaffold for Scapholunate Interosseous Ligament Reconstruction

The scapholunate interosseous ligament (SLIL) is a frequently torn wrist ligament, and current surgical options for SLIL tears are suboptimal. This research aims to develop a novel multiphasic bone-ligament-bone scaffold (BLB) with a porous interface using 3D-printing and cell sheet technology for the reconstruction of the dorsal scapholunate interosseous ligament. The BLB comprises two bone compartments bridged by aligned polycaprolactone fibers mimicking the architecture of the native tissue. Mechanical testing of the BLBs shows their ability to withstand physiological forces. Combination of the BLB with human bone marrow mesenchymal stem cell sheet demonstrates that the harvesting did not compromise cell viability, while allowing homogeneous distribution in the ligament compartment. The BLBs are loaded with cell sheets and bone morphogenetic protein-2 in the ligament and bone compartment respectively prior to ectopic implantation into athymic rats. The histology demonstrates rapid tissue infiltration, high vascularization, and more importantly the maintenance of the compartmentalization as bone formation remains localized to the bone compartment despite the porous interface. The cells in the ligament compartment become preferentially aligned, and this proof-of-concept study demonstrates that the BLB can provide sufficient compartmentalization and fiber guiding properties necessary for the regeneration of the dorsal SLIL.

The Quantitative Anatomy of the Dorsal Scapholunate Interosseous Ligament

BACKGROUND

The anatomy of the scapholunate interosseous ligament (SLIL) has been described qualitatively in great detail, with recognition of the dorsal component's importance for carpal stability. The purpose of this study was to define the quantitative anatomy of the dorsal SLIL and to assess the use of high-frequency ultrasound to image the dorsal SLIL.

METHODS

We used high-frequency ultrasound imaging to evaluate 40 wrists in 20 volunteers and recorded the radial-ulnar (length) and dorsal-volar (thickness) dimensions of the dorsal SLIL and the dimensions of the scapholunate interval. We assessed the use of high-frequency ultrasound by comparing the length and thickness of the dorsal SLIL on ultrasound evaluation and open dissection of 12 cadaveric wrists. Student's t test was used to assess the relationship between measurements obtained on cadaver ultrasound and open dissection.

RESULTS

In the volunteer wrists, the mean dorsal SLIL length was 7.5 ± 1.4 mm and thickness was 1.8 ± 0.4 mm; the mean scapholunate interval was 5.0 mm dorsally and 2.5 mm centrally. In the cadaver wrists, there was no difference in dorsal SLIL length or thickness between ultrasound and open dissection.

CONCLUSIONS

The dorsal SLIL is approximately 7.5 mm long and 1.8 mm thick. These parameters may be useful in treatment of SLIL injuries to restore the native anatomy. High-frequency ultrasound is a useful imaging technique to assess the dorsal SLIL, although further study is needed to assess the use of high-frequency ultrasound in detection of SLIL pathology.

Tensile and Torsional Structural Properties of the Native Scapholunate Ligament

PURPOSE

The ideal material for reconstruction of the scapholunate interosseous ligament (SLIL) should replicate the mechanical properties of the native SLIL to recreate normal kinematics and prevent posttraumatic arthritis. The purpose of our study was to evaluate the cyclic torsional and tensile properties of the native SLIL and load to failure tensile properties of the dorsal SLIL.

METHODS

The SLIL bone complex was resected from 10 fresh-frozen cadavers. The scaphoid and lunate were secured in polymethylmethacrylate and mounted on a test machine that incorporated an x-y stage and universal joint, which permitted translations perpendicular to the rotation/pull axis as well as nonaxial angulations. After a 1 N preload, specimens underwent cyclic torsional testing (±0.45 N m flexion/extension at 0.5 Hz) and tensile testing (1-50 N at 1 Hz) for 500 cycles. Lastly, the dorsal 10 mm of the SLIL was isolated and displaced at 10 mm/min until failure.

RESULTS

During intact SLIL cyclic torsional testing, the neutral zone was 29.7° ± 6.6° and the range of rotation 46.6° ± 7.1°. Stiffness in flexion and extension were 0.11 ± 0.02 and 0.12 ± 0.02 N m/deg, respectively. During cyclic tensile testing, the engagement length was 0.2 ± 0.1 mm, the mean stiffness was 276 ± 67 N/mm, and the range of displacement was 0.4 ± 0.1 mm. The dorsal SLIL displayed a 0.3 ± 0.2 mm engagement length, 240 ± 65 N/mm stiffness, peak load of 270 ± 91 N, and displacement at peak load of 1.8 ± 0.3 mm.

CONCLUSIONS

We report the torsional properties of the SLIL. Our novel test setup allows for free rotation and translation, which reduces out-of-plane force application. This may explain our observation of greater dorsal SLIL load to failure than previous reports.

CLINICAL RELEVANCE

By matching the natural ligament with respect to its tensile and torsional properties, we believe that reconstructions will better restore the natural kinematics of the wrist and lead to improved outcomes. Future clinical studies should aim to investigate this further.

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.

Experiences with Osteoligamentoplasty According to Weiss for the Treatment of Scapholunate Dissociation

BACKGROUND

In post-traumatic, dynamic, or static scapholunate (SL) instability, an SL ligament reconstruction is advisable to avoid long-term complications. However, a sufficient primary reconstruction is best achieved in acute injuries. For chronic SL dissociation, there is still no satisfying standard surgical technique. In this context, we evaluated the clinical outcome of Weiss's osteoligamentoplasty as a treatment option.

METHODS

Over a three-year period, 16 patients with chronic and symptomatic SL dissociation Grade-II and III, without the signs of osteoarthrosis were, surgically treated using a bone-retinaculum-bone autograft from the distal radius. All patients underwent prior wrist arthroscopy. The clinical outcome was measured using the Mayo-Wrist, Krimmer, and DASH score. In addition, radiological measurements were also performed.

RESULTS

The postoperative clinical outcome successfully increased the Mayo-Wrist score: 32 to 64 points, Krimmer score: 30 to 53 points and DASH score: 41 to 30 points. The radiological follow-up demonstrated no evidence of an SL gap or significant loss of reposition in the SL angle in 13 of the 16 cases. Till date, two patients had to be revised to an arthrodesis.

CONCLUSIONS

The autogenous osteoligamentary span from the distal radius improves a chronic SL dissociation and, therefore, presents a suitable option to anatomically reconstruct the SL ligament. It leads to a proper realignment of the carpus and could help to prevent arthritic changes of the wrist. Nevertheless, in patients with postoperative high occupational physical strain, the procedure should be performed with reservations. As long as there is no satisfying standard surgical treatment, Weiss's osteoligamentoplasty is a convincing technique.

Force in the Scapholunate Interosseous Ligament During 2 Simulated Pushup Positions

PURPOSE

To determine the in vitro force between the scaphoid and the lunate supported by the scapholunate interosseous ligament (SLIL) during 2 wrist pushup positions.

METHODS

Six fresh-frozen cadaveric wrists were tested in a neutral flexion-extension (knuckle) pushup position and in an extended pushup position. Tensile forces were measured across the scapholunate joint as half body weight axial forces were applied through the radius and ulna. Forces were measured after sectioning the SLIL, after also sectioning the dorsal radiocarpal and dorsal intercarpal ligaments, and then after also sectioning the radioscaphocapitate ligament.

RESULTS

In the neutral position with the SLIL sectioned, the tensile force across the scapholunate joint was significantly larger in the extended position (45 N) than in the neutral position (25 N). Sectioning additional ligaments did not significantly increase the measured force. Extrapolation of the measured force in wrist extension with application of 1 time body weight suggests a force of 110 N would occur in the SLIL.

CONCLUSIONS

This study demonstrated that, with the SLIL sectioned, with or without the dorsal radiocarpal, dorsal intercarpal, and radioscaphocapitate ligaments sectioned, the tensile force across the scapholunate joint is greater in extension than in the neutral wrist position.

CLINICAL RELEVANCE

This study helps characterize the forces experienced across the scapholunate articulation when the SLIL is disrupted.

An arthroscopic-assisted minimal invasive method for the reconstruction of the scapho-lunate ligament using a bone-ligament-bone graft

We report the outcomes of an arthroscopic-assisted minimally invasive technique to reconstruct the scapho-lunate ligament using a bone-ligament-bone graft in 11 patients (11 wrists). The mean follow-up time was 29 months (range 20 to 38). The preoperative mean wrist flexion, extension, grip strength and patient-rated wrist evaluation score values were 61°, 54°, 115 N and 54, respectively. The postoperative mean values were 64°, 58°, 142 N and 15, respectively. There were no statistical differences between the pre- and postoperative wrist flexion and extension, whereas changes in grip strength and patient-rated wrist evaluation score were significant. Scapho-lunate angles decreased significantly from 69° to 60°. Based on our clinical outcomes, this method provides a reliable alterative for the reconstruction of the scapho-lunate ligament in patients with persistent Geissler type 3 and 4 lesions in the short-term.

LEVEL OF EVIDENCE

IV.

Mid-term results of ligament tenodesis in treatment of scapholunate dissociation: a retrospective study of 20 patients

The purpose of this retrospective study was to assess the modified Brunelli technique for the treatment of chronic irreparable complete scapholunate ligament rupture, causing a reducible carpal malalignment without secondary osteoarthritis. A total of 20 patients were treated using this technique. At a mean follow-up period of 24 months (range 6-53, SD 15), pain on a visual analogue scale had improved from 6 (range 3-10) to 3 (range 0-7). Function measured with the DASH score had improved from 37 (range 11-90) to 20 (range 0-53). Range of motion was reduced in flexion by a mean of 19° (range 10-45), and in extension by a mean of 14° (range 0-35). Mean grip strength at last follow-up was 81% of the uninjured hand (range 50-100%) Three patients developed scapholunate advanced collapse (stage II) requiring salvage surgery. Scapholunate ligament reconstruction with the modified Brunelli technique showed satisfactory results in this study. Extended studies are needed to determine the long-term benefits of this reconstructive procedure.

LEVEL OF EVIDENCE

IV.

Scapholunate Interosseous Ligament Anatomy and Biomechanics

Injury to the scapholunate interosseous ligament is one of the most common causes of carpal instability and can impart considerable compromise to the patient's hand function. However, the management of scapholunate ligament injuries remains a dynamic concept, especially with regard to the multitude of options and techniques that exist for its surgical treatment. We present a thorough review of scapholunate anatomy and morphology, and the role of the scapholunate articulations in the kinetics and pathomechanics of wrist instability. We also review the current literature on the biomechanical properties of the scapholunate ligament and its subcomponents. A sound understanding of the anatomy and biomechanics of the scapholunate ligament can clarify its instability and may better orient current reconstructive procedures or pioneer better future techniques.

Chronic Scapholunate Ligament Injury: Techniques in Repair and Reconstruction

Although the true incidence of scapholunate interosseous ligament (SLIL) injury is unknown, a study found that 35% of cadaveric wrists had some degree of scapholunate tear. Of those wrists with SLIL injury, 29% had evidence of arthrosis. Early recognition and treatment of these injuries can delay or prevent the onset of arthritis. This article details treatment options for SLIL injury across the spectrum of pathology with a particular emphasis on chronic scapholunate repair and reconstruction. New techniques and outcomes data also are presented.

Force in the Scapholunate Interosseous Ligament During Active Wrist Motion

PURPOSE

To examine the force experienced by the scapholunate interosseous ligament (SLIL) during movements of the wrist.

METHODS

Six fresh-frozen cadaveric wrists were freed of soft tissue and tested in a computer controlled, servohydraulic simulator. Each wrist was tested cyclically through simulated active arcs of flexion-extension and dart throw motion. Tensile forces were recorded across the scapholunate joint with the SLIL cut through a cable placed through the scaphoid to the lunate and fixed to a force transducer external to the wrist.

RESULTS

The average recorded maximal tensile force across the scapholunate joint during all tested motions was 20 N. During wrist flexion-extension and the dart throw motion, SLIL force was greater at maximum extension than at maximum flexion. No significant differences among the different motions at maximum flexion or extension or for maximal force during motion were found.

CONCLUSIONS

Forces during the flexion-extension and dart throw motions were significantly higher in extension than in flexion. However, during simple unresisted wrist motions, the force did not exceed 20 N.

CLINICAL RELEVANCE

This information can be used to evaluate surgical methods used for SLIL repairs and thus provide better outcomes for patients.

Bone-Retinaculum-Bone Autografts for Scapholunate Interosseous Ligament Reconstruction

Carpal instability arising from an injury to the scapholunate interosseous ligament (SLIL) is commonly seen and treated by hand surgeons. No technique to this date has proved to provide optimal results for primary repair of acute SLIL tear and the treatment of chronic tears of the SLIL. Recently, attention has shifted toward replacement of the dorsal aspect of the SLIL, which is the most structurally and functionally important aspect of the SLIL. This article describes the indications, surgical technique, postoperative treatment and expected results of the use of a bone-retinaculum-bone autograft procedure in the treatment of scapholunate instability.

Midterm Outcome of Bone-Ligament-Bone Graft and Dorsal Capsulodesis for Chronic Scapholunate Instability

PURPOSE

To assess midterm outcomes of our bone-ligament-bone (BLB) grafts for chronic scapholunate (SL) instability and better define criteria for their use.

METHODS

We conducted a retrospective review of 26 patients treated with BLB grafts and dorsal capsulodesis between 1997 and 2009. Twenty-four patients were reviewed. Mean follow-up was 8.2 years. Two patients had dynamic lesions, 7 had SL dissociation, 14 had a dorsal intercalated segment instability lesion, and 1 had SL advanced collapse stage 1. Mean age at surgery was 46 years. All patients presented with pain and 14 had lack of strength. Results were reviewed clinically and radiologically. Images were assessed by 4 surgeons and 1 radiologist for radial styloid, radioscaphoid, radiolunate, midcarpal, and scaphotrapeziotrapezoid degenerative changes.

RESULTS

Five patients needed subsequent 4-corner arthrodesis. Of the remaining 19 patients at follow-up, both extension and flexion decreased to 73% of the contralateral side. Postoperative grip strength improved from 78% to 90% of the nonsurgical wrist. Quick Disabilities of the Arm, Shoulder, and Hand score was 10 of 100 and the Patient-Rated Wrist Evaluation score was 10 of 100. Radiologically, the SL gap was improved and maintained at follow-up. The SL angle (mean before surgery, 79°) was initially corrected to 69° but returned to preoperative values at follow-up. Eleven of the 19 cases had signs of midcarpal arthritis.

CONCLUSIONS

Bone-ligament-bone grafts with SL dorsal capsulodesis were able to restore and maintain an improved SL interval in all patients. The technique achieved good clinical results and high patient satisfaction, but it did not stop the progression of arthritis, particularly at the midcarpal level. This technique is an option for isolated unrepairable lesion of the dorsal SL ligament with an easily correctable lunate and especially when restoration of grip strength is important.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

The modified Brunelli procedure for scapholunate instability: a single centre study

Management of scapholunate (SL) instability remains controversial. The modified Brunelli procedure is a soft tissue procedure that recreates the stabilising forces of the SL ligament using a split flexor carpi radialis tendon graft passed from volar to dorsal via a tunnel in the distal pole of the scaphoid. Thirteen consecutive patients with an average age of 35 years underwent the modified Brunelli procedure. Pain improved from a mean visual analog score of eight preoperatively to 1.5. The DASH score improved from a preoperative score of 55.4 to 34.9 as did the grip strength from 40% to 75% respectively. All wrist ranges of motion were decreased post-operatively in particular wrist flexion. SL ligament reconstruction using the modified Brunelli procedure resulted in satisfactory outcomes. Post-operatively patients were relatively pain free, with improved grip strength. The range of motion was reduced postoperatively, however did not restrict return to work or premorbid activities.

Biomechanical comparison of the hand-based transplant used in bone-tissue-bone scapho-lunate ligament reconstruction

Although work has been published comparing the five most commonly used transplant techniques to the properties of the scapho-lunate interosseous ligament (SLIL), no study has been carried out which compares the biomechanical properties of the different bone-tissue-bone autografts to each other, using a standard methodology of testing. The hypothesis of this study was that mechanically significant differences in the material properties of commonly used bone-tissue-bone exist when compared to each other. We tested the dorsal part of the SLIL and the five most quoted transplants in the literature: capitate to trapezoid; trapezoid to second metacarpal; third metacarpal-carpal; dorsal capitate-hamate; 4-5 extensor retinaculum. For each transplant, we measured failure load, failure displacement, width, and thickness. Anova was used to compare the different results obtained and the level of significance attributed to P<0.05. Load to failure were: SLIL 94.3±42.86N; capitate to trapezoid 37.7±23.13N; trapezoid to second metacarpal 45.43±14.28N; third metacarpal-carpal 60.11±19.94N; dorsal capitate-hamate 63±25.51N; 4-5 retinaculum 15.67±10.7N. Only the dorsal capitate-hamate ligament showed to have no significant (P>0.05) difference in term of load to failure, all the others was significantly weaker (P<0.05). Previous biomechanical studies have identified the dorsal region of the SLIL as the most structurally and functionally important area of the SLIL. As a result, attention has been more specifically brought to the replacement of the dorsal portion of the SLIL. An attempt to achieve a reconstruction that reproduces more closely the SLIL has generated research on the use of bone-tissue-bone composite graft, several donor sites have been used in order to find the most similar. Our results suggest that, using a normalized method to compare the previously described grafts harvested at the wrist level, that the dorsal capitate-hamate ligament has the closest properties to the native dorsal scapho-lunate ligament.

Assessment of scapholunate instability and review of evidence for management in the absence of arthritis

Scapholunate ligament tear is a common wrist injury and may lead to degenerative arthritis of the wrist in the long term. We review the assessment and classification of scapholunate instability and discuss the findings from our search for evidence for the management of scapholunate instability in the absence of arthritis. Strong evidence (level 1 or 2) for management is lacking and published recommendations are largely experience-based. The choice of procedure in the absence of arthritis depends on the extent of the tear, quality of the ligament remnants, and reducibility of the joint. Prospective, randomized studies with validated outcome measures are needed to establish the efficacy of intervention on symptoms and function and its effect on the risk of future arthritis.

Reconstruction of both volar and dorsal limbs of the scapholunate interosseous ligament

Complete scapholunate interosseous ligament deficiency can lead to pain, reduced functional performance, and scapholunate advanced collapse arthritis. Efforts to restore carpal stability began with procedures to tether scaphoid motion. Techniques evolved to include multiple differing strategies of linking the scaphoid to the lunate dorsally in the transverse plane. Actually restoring stability has proven elusive owing to the impossibility of truly replicating the original anatomy and the multidirectional forces to which the scapholunate interface is subjected. The described surgical technique differs from others by reconstructing both the volar and dorsal limbs of the scapholunate ligament and accounting for the multiple force vectors involved in scapholunate instability.

Current role of open reconstruction of the scapholunate ligament

This paper is a review of the various surgical techniques used in repair or reconstruction of the scapholunate ligament according to the clinical stages and anatomic-pathologic findings. Arthroscopy permits a direct evaluation of the scapholunate injury and the status of the articular surfaces. Specific indications for each type of scapholunate ligament tear are proposed, from the different types of dorsal capsulodesis to bone-ligament-bone techniques and tenodesis procedures. The authors' preferred techniques and literature review of the expected outcomes are presented.

Long-term results of bone-retinaculum-bone autograft for scapholunate instability

PURPOSE

To report long-term follow-up of scapholunate interosseous ligament reconstruction with bone-retinaculum-bone autograft in patients with dynamic scapholunate instability.

METHODS

Of the 14 patients from the previously reported cohort who had bone-retinaculum-bone autograft for dynamic instability, 6 returned for clinical examination and radiographs, 3 were reached by telephone, and 2 were lost to follow-up. The remaining 3 had salvage procedures (2 total wrist arthrodeses and 1 proximal row carpectomy) between the prior report and the current study and thus reached an endpoint, at 2 to 4 years. For the 6 who returned, outcome measurements included scapholunate angle and gap, radiographic evidence of secondary arthritis, wrist extension and flexion, grip strength, and Mayo wrist score.

RESULTS

Follow-up averaged 11.9 years (range, 10.7-14.1 y). Clinical and radiographic outcomes deteriorated moderately from the prior report. Mayo wrist score averaged 83. There were 3 failures, resulting in 1 proximal row carpectomy and 2 total wrist arthrodeses. Findings at repeat surgery in the failed group included an intact graft without any apparent abnormalities, a partially ruptured graft (after a subsequent re-injury), and a completely resorbed graft.

CONCLUSIONS

Bone-retinaculum-bone autograft reconstruction is a viable treatment option for dynamic scapholunate instability in which the scaphoid and lunate can be reduced. Results may deteriorate but are similar to those reported previously from other techniques. Problems with graft strength or stiffness may necessitate further surgery.

Tissue-engineered collateral ligament composite allografts for scapholunate ligament reconstruction: an experimental study

PURPOSE

In patients with chronic scapholunate (SL) dissociation or dynamic instability, ligament repair is often not possible, and surgical reconstruction is indicated. The ideal graft ligament would recreate both anatomical and biomechanical properties of the dorsal scapholunate ligament (dorsal SLIL). The finger proximal interphalangeal joint (PIP joint) collateral ligament could possibly be a substitute ligament.

METHODS

We harvested human PIP joint collateral ligaments and SL ligaments from 15 cadaveric limbs. We recorded ligament length, width, and thickness, and measured the biomechanical properties (ultimate load, stiffness, and displacement to failure) of native dorsal SLIL, untreated collateral ligaments, decellularized collateral ligaments, and SL repairs with bone-collateral ligament-bone composite collateral ligament grafts. As proof of concept, we then reseeded decellularized bone-collateral ligament-bone composite grafts with green fluorescent protein-labeled adipo-derived mesenchymal stem cells and evaluated them histologically.

RESULTS

There was no difference in ultimate load, stiffness, and displacement to failure among native dorsal SLIL, untreated and decellularized collateral ligaments, and SL repairs with tissue-engineered collateral ligament grafts. With pair-matched untreated and decellularized scaffolds, there was no difference in ultimate load or stiffness. However, decellularized ligaments revealed lower displacement to failure compared with untreated ligaments. There was no difference in displacement between decellularized ligaments and native dorsal SLIL. We successfully decellularized grafts with recently described techniques, and they could be similarly reseeded.

CONCLUSIONS

Proximal interphalangeal joint collateral ligament-based bone-collateral ligament-bone composite allografts had biomechanical properties similar to those of native dorsal SLIL. Decellularization did not adversely affect material properties.

CLINICAL RELEVANCE

These tissue-engineered grafts may offer surgeons another option for reconstruction of chronic SL instability.

Scapholunate ligament reconstruction using an acellular dermal matrix: a mechanical study

PURPOSE

Numerous surgical techniques have been described for the treatment of chronic scapholunate ligament instability. We hypothesized that scapholunate ligament reconstruction using an acellular dermal matrix was biomechanically comparable to previously described surgical reconstructions.

METHODS

The scaphoid and lunate with the entire scapholunate ligament were harvested from 15 cadaveric specimens. The scapholunate ligament was transected and reconstructed using an acellular dermal matrix (Arthroflex; LifeNet Health, Virginia Beach, VA) and 4 micro suture anchors in 10 specimens. Five specimens were kept with the native scapholunate ligament intact. Five other specimens were reconstructed using a 1.0-mm-thick dermal matrix, and a second cohort of 5 specimens was reconstructed using a 1.5-mm-thick matrix. Tensile testing of all specimens was performed using a servohydraulic material testing system and data acquisition software. The tensile test apparatus applied a distractive load of 10 mm/min (0.17 mm/s) until the specimens reached ultimate failure. Failure force, failure displacement, stiffness, and energy to failure were calculated.

RESULTS

All 5 specimens in the intact group failed at the scapholunate ligament midsubstance. The mean ultimate failure force was 172 N, with mean stiffness of 74 N/mm. In the reconstruction group with 1.0-mm dermal matrices, the mode of failure was at the suture-matrix interface in all specimens, whereas the 1.5-mm dermal matrix reconstruction cohort all failed at the bone-suture anchor interface. In the 1.0-mm reconstruction group, the mean ultimate failure force was 77 N, with mean stiffness of 24 N/mm. In the 1.5-mm dermal matrix reconstruction cohort, the mean ultimate failure force was 111 N, with mean stiffness of 30 N/mm.

CONCLUSIONS

Scapholunate ligament reconstruction using acellular dermal matrix and suture anchors demonstrated similar biomechanical properties to previously described reconstruction techniques.

CLINICAL RELEVANCE

Scapholunate ligament reconstruction using acellular dermal matrix warrants clinical investigation as a potential treatment alternative for chronic scapholunate instability.

Biomechanical properties of the scapholunate ligament and the importance of its portions in the capitate intrusion injury

BACKGROUND

Repair of the dorsal component of the scapholunate ligament alone is the usual surgical treatment for scapholunate injuries. Recent literature has suggested that additionally repairing the palmar component of the scapholunate ligament leads to improved and lasting clinical outcomes. The aim of this study was to determine the biomechanical properties of both portions of scapholunate ligaments derived from the same wrist and compare them with the whole scapholunate ligament. The goal was to further elucidate the importance of the palmar portion of the scapholunate ligament from a biomechanical perspective.

METHODS

Scapholunate ligaments and their components were harvested from the same fresh frozen cadaveric wrists. Force at failure and stiffness were measured.

FINDINGS

The mean maximum loads to failure for the entire scapholunate ligament, dοrsal and palmar portions were found to be 147 (SD 54)N, 83 (SD 18)N and 86 (SD 16)N respectively. No statistical difference was found between the mean maximum load and stiffness for palmar and dorsal components (P=0.05). Mean maximum load and stiffness, of the intermediate portion, were 36 (SD 15)N and 25 (SD 23)N/mm.

INTERPRETATION

Our biomechanical findings on the dorsal and palmar portions of the scapholunate ligament suggest that each portion contributes approximately 50% to the whole ligament tensile force. These results appear to agree with other reports about the stabilizing role of the palmar portion of the scapholunate ligament and suggest that the palmar portion of the ligament should be considered for surgical repair.

[Treatment of chronic scapholunate dissociation using Cuénod's bone-ligament-bone autograft]

OBJECTIVE

Correction of chronic scapholunate dissociation by replacement of the biomechanically most important dorsal part of the scapholunate ligament using a bone-ligament-bone autograft taken from the carpometacarpal joint II and, additionally, a modified dorsal capsulodesis.

INDICATIONS

Nonfixed chronic scapholunate dissociation without useful remnants of the ligament in which loss of the dorsal part of the scapholunate ligament is the crucial pathophysiological moment.

CONTRAINDICATIONS

Chronic scapholunate dissociation with fixed deformity. Osteoarthritis.

SURGICAL TECHNIQUE

Dorsal incision. Approach to the wrist using the capsular flap described by Berger. Reduction of deformity and temporary transfixation of the scaphoid to the capitate as well as to the lunate. Creation of a trough at the ulnar edge of the dorsal aspect of the scaphoid and another trough at the radial edge of the dorsal aspect of the lunate. Fixation of an exactly fitting bone-ligament-bone autograft taken from the trapezoidometacarpal joint II with 1.2-mm screws into the troughs. Fixation of a part of the dorsal intercarpal ligament which is based on the scaphoid to the lunate using a bone anchor.

POSTOPERATIVE MANAGEMENT

Immobilization using a below-elbow cast including the metacarpophalangeal joint of the thumb for 8 weeks; removal of Kirschner wires 10 weeks postoperatively; after Kirschner wire removal physiotherapy to improve range of motion.

RESULTS

Twelve out of 16 male patients were available for a clinical and radiologic examination after a mean follow-up time of 6.3 years (minimum 1.6, maximum 7.3 years). Clinical results were excellent. The modified Mayo Wrist Score averaged 87 points (minimum 65, maximum 100 points). Eleven patients had an excellent or good result, none of the patients showed a poor result. The DASH Score (Disability of the Arm, Shoulder and Hand) was 13 points on average (minimum 0, maximum 42 points). All patients would have the same operation again. Radiologically, a stretching of the bone-ligament-bone autograft was found in six cases. A symptomatic SLAC (scapholunate advanced collapse) wrist with the need for a salvage operation could not be observed.

A three-dimensional finite element model of maximal grip loading in the human wrist

The aim of this work was to create an anatomically accurate three-dimensional finite element model of the wrist, applying subject-specific loading and quantifying the internal load transfer through the joint during maximal grip. For three subjects, representing the anatomical variation at the wrist, loading on each digit was measured during a maximal grip strength test with simultaneous motion capture. The internal metacarpophalangeal joint load was calculated using a biomechanical model. High-resolution magnetic resonance scans were acquired to quantify bone geometry. Finite element analysis was performed, with ligaments and tendons added, to calculate the internal load distribution. It was found that for the maximal grip the thumb carried the highest load, an average of 72.2 +/- 20.1 N in the neutral position. Results from the finite element model suggested that the highest regions of stress were located at the radial aspect of the carpus. Most of the load was transmitted through the radius, 87.5 per cent, as opposed to 12.5 per cent through the ulna with the wrist in a neutral position. A fully three-dimensional finite element analysis of the wrist using subject-specific anatomy and loading conditions was performed. The study emphasizes the importance of modelling a large ensemble of subjects in order to capture the spectrum of the load transfer through the wrist due to anatomical variation.

Linear and torsional mechanical characteristics of intact and reconstructed scapholunate ligaments

The mechanical behavior of human scapholunate ligaments is not well understood. Presently, intact scapholunate specimens were mechanically tested in linear distraction and torsion. Fresh bovine tendon grafts were used to reconstruct the scapholunate interval and the tests repeated. Tests yielded the following average values for intact specimens: linear stiffness (48.9 Nmm), linear load retained at 100 s (44%), torsional stiffness (19.5 N mmdeg), torque remaining at 100 seconds (66%), torque-to-failure (1253.9 N mm), and angle-to-failure (50.4 deg). Tests showed the following average values for reconstructed specimens: linear stiffness (5.4 Nmm), linear load retained at 100 s (49%), torsional stiffness (12.6 N mmdeg), torque remaining at 100 s (71%), torque-to-failure (936.8 N mm), and angle-to-failure (54.5 deg). There were no statistically significant differences between the intact and reconstructed specimens, with the exception of linear stiffness. Biomechanically, this is the first study in the literature to quantify torsional stress relaxation, failure torque, and failure angle for the intact and repaired human scapholunate ligament. Surgically, reconstruction with bovine tendon may warrant further investigation as a method to potentially retain function and strength after scapholunate injury.

[New bone-ligament-bone transplant from plantar plates of the toes and possible use in reconstruction of the scapholunate ligament. An anatomical study]

BACKGROUND

Various treatment options have been proposed for reconstruction of the scapholunate ligament. However, none of these methods prevent patients with scapholunate instability from developing wrist arthritis. This study was performed to investigate a new bone-ligament-bone autograft from the plantar plate of the toes for suitable reconstruction of the scapholunate interosseus ligament. The anatomical properties and the technical feasibility were investigated.

METHODS

The plantar plates of the metatarso-phalangeal joints and the proximal interphalangeal joints of the 2nd-5th toes were examined in 20 cadaver feet and measurements such as length, thickness and width were recorded.

RESULTS

The average lengths of the plantar ligaments of the proximal interphalangeal joint were 0.63 cm (D3) and 0.62 cm (D4), respectively and were therefore found to be similar to that of the scapholunate ligament. Bone-ligament-bone autografts of the plantar plates were designed and intercalated between the scaphoid and lunate bones and, contrary to all previous methods, not simply superimposed upon them.

CONCLUSIONS

It can be concluded from the data that this new graft of the proximal interphalangeal joint of the 3rd and 4th toes can be a suitable replacement for the scapholunate ligament.

Distal tunnel placement improves scaphoid flexion with the Brunelli tenodesis procedure for scapholunate dissociation

PURPOSE

Treatment of scapholunate dissociation remains difficult. The modified Brunelli procedure, a flexor carpi radialis tenodesis through the scaphoid and secured with dorsal wrist ligaments, has shown promising results. This study compares the biomechanical effects on scaphoid flexion and scapholunate gap between proximal and distal tunnel placement in the modified Brunelli procedure.

METHODS

Eight fresh-frozen cadaveric forearms were used. A dorsal approach to the wrist through the floor of the fourth compartment was used. Metallic markers were implanted into the scaphoid and lunate. Tunnels were drilled through the proximal and distal poles of the scaphoid. Wrists were positioned in neutral and loaded to 100 N through the wrist flexor and extensor tendons. Posteroanterior and lateral radiographs were taken with the scapholunate interval intact, with the scapholunate interval sectioned, and after the modified Brunelli tenodesis was performed through the proximal and then distal tunnels using Mersilene tape. Radiographs were analyzed for change in scapholunate angle and scapholunate gap. Multivariate analysis of variance was performed to assess statistical significance for each state compared with the intact wrist.

RESULTS

In the intact wrist, the mean scapholunate gap was 1.6 mm +/- 0.1. With the scapholunate interval sectioned, the scapholunate angle increased by 26 degrees +/- 12 and gap increased to 4.2 mm +/- 1.2. With a proximal tunnel for the modified Brunelli procedure, the change in scapholunate angle decreased to 15 degrees +/- 10 and gap decreased to 1.8 mm +/- 0.3. With a distal tunnel for the modified Brunelli procedure, the change in scapholunate angle decreased to 4 degrees +/- 7 and gap decreased to 1.3 mm +/- 0.2.

CONCLUSIONS

These biomechanical data suggest that a tunnel exiting in the distal pole of the scaphoid results in better correction of scaphoid flexion when performing the modified Brunelli procedure.

Results of the modified Brunelli tenodesis for treatment of scapholunate instability: a retrospective study of 19 patients

PURPOSE

Management of chronic scapholunate (SL) instability without osteoarthritis remains controversial. In order to recreate an SL interosseous linkage, some surgeons opt for a limited wrist arthrodesis, whereas others use soft tissue stabilization. The purpose of the current study was to review and assess the therapeutic benefit of the modified Brunelli tenodesis that used the flexor carpi radialis tendon to replicate the stabilizing ligaments of the scaphoid.

METHODS

Between 2001 and 2005, 19 tenodesis procedures have been performed to correct dynamic or static SL instability without osteoarthritis. On average, patients had surgery 15 months after injury. The mean follow-up was 37 months.

RESULTS

After surgery, 15 patients had no to mild pain with a mean visual analog scale score of 3 of 10. The average wrist motion was 50 degrees extension, 41 degrees flexion, 24 degrees radial deviation, and 29 degrees ulnar deviation (75%, 73%, 68%, and 86% of the uninvolved wrists, respectively). The grip strength was 78% of the uninvolved wrists. On radiographs, the mean static SL distance was 2.4 mm (2.8 mm before surgery). There was no widening of the SL gap compared to the immediate postoperative gap. The SL angle improved from a mean preoperative value of 61 degrees to 53 degrees immediately after surgery and rose again to 62 degrees at the time of the review. One patient developed a scapholunate advanced collapse wrist stage 2.

CONCLUSIONS

Ligament reconstruction using tendon grafts gave satisfactory results to correct reducible chronic SL instability without osteoarthritis. This repair technique achieved a relatively pain-free wrist, with acceptable grip strength and normal SL distance but with a loss in the arc of motion and a loss of correction of SL angle.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

A biomechanical assessment of the coupling of torsion and tension in the human scapholunate ligament

The mechanical behaviour of human scapholunate ligaments is not well described in the literature with regard to torsion. In this study, intact scapholunate specimens were mechanically tested in torsion to determine whether a simultaneous tensile load was generated. Human intact scapholunate specimens ( n = 19) were harvested. The scaphoid and lunate bones were potted in square chambers using epoxy cement, while the interposing ligament remained exposed. Each specimen was mounted rigidly in a specially designed test jig and remained at a fixed axial length during all tests. Specimens were subjected to a torsional load regime that included cyclic preconditioning, ramp-up, stress relaxation, ramp-down, rest, and torsion to failure. Torque and axial tension were monitored simultaneously. The relationship between torsion and tension was determined. Graphs of torque versus tension were generated, from which outcome measures were extracted. Tests demonstrated a clear relationship between applied torsion and the resulting generation of tension for the ligament during ramp-up (torsion-to-tension ratio, 38.86 ± 29.00 mm; linearity coefficient R2 = 0.89 ± 0.15; n = 19), stress relaxation (torsion-to-tension ratio, 23.43 ± 15.84 mm; R2 = 0.90 ± 0.09; n = 16), and failure tests (torsion-to-tension ratio, 38.81 ± 26.39 mm; R2 = 0.77 ± 0.20; n = 16). No statistically significant differences were detected between the torsion-to-tension ratios ( p = 0.13) or between the linearity ( R2) of the best-fit lines ( p > 0.085). A strongly coupled linear relationship between torsion and tension for the scapholunate ligament was exhibited in all test phases. This may suggest interplay between these two parameters in the stabilization of the ligament during normal motion and for injury cascades.

Scapholunate interosseous ligament reconstruction: results with a modified Brunelli technique versus four-bone weave

PURPOSE

To compare clinical and radiographic outcomes in patients with chronic scapholunate dissociation treated with a modified Brunelli technique versus a 4-bone tendon weave.

METHODS

A retrospective cohort study was performed. Twenty-three patients presented with chronic scapholunate dissociation and were treated with the 4-bone tendon weave technique as described by Almquist and colleagues. A separate group of 21 patients were subsequently treated with a modified Brunelli plus reduction-assisted scapholunate ligament technique. All patients had preoperative radiographs demonstrating scapholunate ligament disruption and positive magnetic resonance arthrograms. All were treated by the senior surgeon (T.E.T.), who initially performed the 4-bone tendon weave and later the modified Brunelli procedure plus temporary screw fixation. Evaluation included radiographic changes, pain and Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire scores, grip strength, and range of motion. Data were analyzed using the Wilcoxon signed rank test for preoperative-to-postoperative comparisons and the Wilcoxon-Mann-Whitney test for comparison between the 2 treatment groups.

RESULTS

The scapholunate angle decreased in both groups (mean 15 degrees +/- 5 decrease for the Brunelli group; 10 degrees +/- 4 decrease in the 4-bone tendon weave group). Mean pain and DASH scores preoperatively and postoperatively demonstrated greater improvement for the modified Brunelli group (pain scores rated on a visual analog scale of 1 to 10: mean difference Brunelli group = 4.8 cm; 4-bone tendon weave group = 3.2 cm; mean difference 1.6 cm; DASH scores: mean difference Brunelli group = 31.5 points; 4-bone tendon weave group = 14.2 points). The Brunelli group also experienced greater postoperative motion as a percentage of preoperative motion (mean 86% +/- 7 vs 60% +/- 12) and significant increases in postoperative versus preoperative grip strength (mean 2 kg vs 1 kg; increase of 1 kg).

CONCLUSIONS

The modified Brunelli technique for scapholunate interosseous ligament reconstruction compared with the 4-bone tendon weave technique has improved outcomes in pain relief, DASH scores, range of motion, and grip strength at 2.5 years follow-up.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

Bone-tissue-bone repairs for scapholunate dissociation

Scapholunate dissociation is a commonly seen and treated form of carpal instability. Several surgical options have been used for the repair of scapholunate instability over the past 50 years. These have included benign neglect, reduction and percutaneous pinning, primary repair, partial fusions, tendon weaves, and combinations of these. Recent advancements in scapholunate repair and anatomy have been aimed at a more physiologic repair. Composite replacement of the entire scapholunate interval, similar to other tendon repairs seen in orthopedic surgery, has become popular. Bone-tissue-bone (BTB) autograft replacement from the foot has been used but the problems of a secondary surgical site have resulted in other graft site selections. Currently more commonly used grafts are bone-retinaculum-bone, third or second metacarpal-carpal bone, or hamate-capitate grafts, all performed with or without screw augmentation. Vascularized autograft replacement on pedicled grafts from the hand is being explored. This review discusses the surgeons' indications and technical details of the surgery. The lack of long-term outcome measurements for these BTB surgeries makes it difficult for the hand surgeon to determine the appropriate use of these treatment modalities, but early reports have indicated that the BTB graft will be an important part of scapholunate dissociation treatment.

A vascularized technique for bone-tissue-bone repair in scapholunate dissociation

Several surgical options have been used for the repair of scapholunate instability over the last 50 years. The many options have included neglect, reduction with percutaneous pinning, primary repair, partial fusions, tendon weaves, and others. Recent advancements in scapholunate repair and anatomy have been aimed at a more physiological repair. Composite replacement of the entire scapholunate interval similar to other tendon repairs seen in orthopedic surgery has become popular. Currently, more common hand-based grafts are bone-retinaculum-bone, third or second metacarpal-carpal bone or hamate-capitate grafts. There still exist some failures in the outcome after any of these procedures. This technique demonstrates the use of a vascularized autograft replacement on a pedicled graft. This procedure is the natural extension of the third or second metacarpal-carpal bone autograft, previously reported in the literature. The use of this proven graft, with a pedicle based on the intermetacarpal artery, may avoid some of the late complications seen with other autografts.

Wrist MR Arthrography: How, Why, When

MR imaging of the wrist frequently represents a diagnostic challenge for radiologists because of the complex anatomy of this joint, small size of its components, and little known pathologic conditions. MR arthrography combines the advantages of conventional MR imaging and arthrography by improving the visualization of small intra-articular abnormalities. This article reviews the current role of MR arthrography in the evaluation of wrist joint disorders considering the relevant aspects of anatomy, techniques, and applications.

Bone-retinaculum-bone reconstruction for chronic posttraumatic instability of the metacarpophalangeal joint of the thumb

PURPOSE

This study presents an autograft technique for the surgical management of chronic posttraumatic instability of the thumb metacarpophalangeal (MCP) joint by using a bone-retinaculum-bone graft from the second compartment of the extensor retinaculum.

METHODS

The bone-retinaculum-bone graft was harvested from the second compartment. The graft ends were fixed into the host site with screws. Fourteen patients (12 ulnar, 2 radial collateral ligament tears) had the procedure. All patients were reviewed by an independent observer using objective and subjective criteria, the mean follow-up time was 20 months.

RESULTS

Results were satisfactory overall (8 excellent, 4 good, 1 fair, 1 poor that subsequently was fused). All patients returned to their former jobs. All but one had a clinically stable first MCP joint; grasp was 87%, pinch was 80%, MCP joint range of motion (ROM) was 91%, and interphalangeal joint ROM was 98% of the unoperated side.

CONCLUSIONS

Early results are encouraging. This procedure preserves ROM of the MCP and interphalangeal joints of the thumb, improves strength, and gives the stability required for proper thumb function.

A mechanical comparison of bone-ligament-bone autografts from the wrist for replacement of the scapholunate ligament

A study was performed to compare the mechanical properties of two intracarpal ligaments with those of the dorsal component of the scapholunate interosseous ligament (SLIL). Trapezoid-to-second metacarpal, capitate-to-trapezoid ligaments, and the dorsal part of the SLIL were obtained as bone-ligament-bone grafts from fresh frozen cadavers. Their respective load to failure and stiffness were measured under uniaxial load on a servohydraulic machine and compared. The capitate-to-trapezoid ligament closely approximated the load to failure and stiffness of the dorsal SLIL, whereas the trapezoid-to-second metacarpal ligament was significantly stronger and stiffer than the dorsal SLIL. These 2 intracarpal bone-ligament-bone grafts share similar mechanical properties with the dorsal component of the scapholunate ligament and might be used clinically to replace it.

Current status of scapholunate interosseous ligament injuries

Injuries to the scapholunate complex present the surgeon with both diagnostic and treatment dilemmas. The anatomic features, biomechanical properties, radiographic appearance, and surgical treatment algorithms of this small but structurally and kinematically important joint continue to be refined. A thorough history and physical examination, combined with a radiographic evaluation that can include plain radiographs, tomography, motion studies, arthrography, or MRI, usually will define the nature of the ligament injury. Arthroscopy is considered the gold standard for complete evaluation of scapholunate interosseous ligament injury and often is performed as a first step before repair or reconstruction. Procedures such as carpal fusions or capsulodesis can limit excessive scaphoid motion, promote wrist stability, and potentially prevent arthritis, but advances continue to be made in direct scapholunate interosseous ligament reconstruction. Challenges for the future involve improving noninvasive evaluation, defining the degree of extrinsic ligament injury, and improving direct repair and reconstruction.

Arthroscopic and open management of dynamic scaphoid instability

This article focuses on the pathophysiology and treatment of dynamic scaphoid instability. Cadaver studies suggest that dynamic instability results from isolated injury to the scapholunate interosseous ligament without damage to the dorsal intercarpal and dorsal radial lunotriquetral ligaments. The diagnosis may be made by dynamic fluoroscopic examination, including stress and load views. The role of arthroscopy is twofold: (1) it enables the surgeon to distinguish between a complete, grossly unstable scapholunate interosseous space that requires open treatment and (2) it permits direct visualization of the reduction and percutaneous pinning of the articulation in an effort to stabilize the joint. Operative indications, open and arthroscopic techniques, and results are discussed.