Reconstruction of the scapholunate ligament in a cadaver model using a bone-ligament-bone autograft from the foot

Multiphasic scaffold for scapholunate interosseous ligament reconstruction: A study in the rabbit knee

Scapholunate interosseous ligament tears are a common wrist injury in young and active patients that can lead to suboptimal outcomes after repair. This research aims to assess a multiphasic scaffold using 3D-printing for reconstruction of the dorsal scapholunate interosseous ligament. The scaffold was surgically implanted in vivo in the position of the native rabbit medial collateral ligament. Two branches of treatment were implemented in the study. In the first group, the rabbits (n = 8) had the knee joint fixed in flexion for 4 weeks using 1.4 mm K-wires prior to sample harvesting. The second group (n = 8) had the rabbit knee joint immobilized for 4 weeks prior to K-wire removal and mobilization for an additional 4 weeks prior to sample harvesting. Overall, samples were harvested at 4 weeks post-surgery (immobilized group) and eight weeks post-surgery (mobilized group). Mechanical tensile testing (n = 5/group) and histology (n = 3/group) of the constructs were conducted. Tissue integration and maturation were observed resulting in increased mechanical strength of the operated joint at 8 weeks (P < .05). Bone and ligament tissues were regenerated in their respective compartments with structural and mechanical properties approaching those reported for the human dorsal SLIL ligament. Clinical Significance: This proof of concept study has demonstrated that the synthetic multiphasic scaffold was capable of regenerating both bone and ligament while also withstanding the physiological load once implanted in the rabbit knee. The artificial scaffold may provide an alternative to current techniques for reconstruction of scapholunate instability or other ligament injuries in the hand and wrist.

The Relationship Between the Tensile and the Torsional Properties of the Native Scapholunate Ligament and Carpal Kinematics

PURPOSE

The purpose of this exploratory study was to examine the relationship between the tensile and the torsional properties of the native scapholunate interosseous ligament (SLIL) and kinematics of the scaphoid and lunate of an intact wrist during passive radioulnar deviation.

METHODS

Eight fresh-frozen cadaveric specimens were transected at the elbow joint and loaded into a custom jig. Kinematic data of the scaphoid and lunate were acquired in a simulated resting condition for 3 wrist positions-neutral, 10° radial deviation, and 30° ulnar deviation-using infrared-emitting rigid body trackers. The SLIL bone-ligament-bone complex was then resected and loaded on a materials testing machine. Specimens underwent cyclic torsional and tensile testing and SLIL tensile and torsional laxity were evaluated. Correlations between scaphoid and lunate rotations and SLIL tensile and torsional properties were determined using Pearson correlation coefficients.

RESULTS

Ulnar deviation of both the scaphoid and the lunate were found to decrease as the laxity of SLIL in torsion increased. In addition, the ratio of lunate flexion-extension to radial-ulnar deviation was found to increase with increased SLIL torsional rotation.

CONCLUSIONS

Our findings support the theory that there is a relationship between scapholunate kinematics and laxity at the level of the interosseous ligaments.

CLINICAL RELEVANCE

Laxity and, specifically, the tensile and torsional properties of an individual's native SLIL should guide reconstruction using a graft material that more closely replicates the individual's native SLIL properties.

Chronic Scapholunate Interosseous Ligament Disruption: A Systematic Review and Meta-Analysis of Surgical Treatments

Background: Although many techniques have been described, there is no clear optimal surgical treatment for chronic scapholunate interosseous ligament (SLIL) disruption. Methods: We identified 255 articles reporting outcomes of SLIL reconstruction. Of these, 40 studies (978 wrists) met eligibility requirements and reported sufficient data on radiographic outcomes to be included in the study. The mean and standard deviation of preoperative and follow-up assessments including scapholunate gap (SLG) and scapholunate angle (SLA) were used to calculate pooled standardized mean differences (SMD) with 95% confidence intervals (CIs). For other radiographic or clinical outcomes, there were not enough reported data to calculate a pooled effect size, and pooled nonstandardized comparisons were made. Results: The SMD between preoperative and postoperative SLA in tenodesis reconstruction was 0.7 (CI, 0.29 to 1.11, P = .001) and 0.04 (CI, -0.27 to 0.38, P = .8) for capsulodesis reconstruction. For SLG, tenodesis demonstrated an SMD of 1.1 (CI, 0.6 to 1.55, P < .001) compared with 0.1 (CI, -0.36 to 0.59, P = .6) for capsulodesis reconstruction. Tenodesis had a significant improvement compared with capsulodesis in SLA (P = .01) and SLG (P = .005). Tenodesis also showed improvement in grip strength and Disabilities of the Arm, Shoulder and Hand scores. Conclusions: Comparing preoperative and postoperative radiographic measurements, tenodesis reconstruction demonstrated significantly improved SLG and SLA relative to capsulodesis. Interpreted in the context of the limitations, existing data demonstrates some benefit of tenodesis reconstruction.

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.

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.

Reconstruction of the Scapholunate Ligament Using Capitohamate Bone-Ligament-Bone

Background The biomechanical properties of the capitohamate (CH) ligament are equivalent to those of the scapholunate (SL) interosseous ligament. We reconstructed the SL ligament using the CH bone-ligament-bone substitute for chronic injury of the SL ligament. Patients and Methods Beginning in 2008, 15 wrists of 14 patients with an average age of 38 years underwent this procedure with a minimum follow-up of 2 years. Thirteen wrists had an SL joint gap more than 3 mm, and two had a complete SL ligament disruption with a severe dorsal intercalated segment instability (DISI) deformity. Kirschner wires (K-wires) were removed 8 weeks after the surgery, then active ROM exercise began. Pain (on visual analog scale [VAS]), wrist motion (angle), radiographic characteristics, such as SL gap (mm) and SL angle, and Modified Mayo Wrist Score (MMWS) were evaluated. Technique The SL joint was reduced by manipulation or with the use of joysticks, then temporary fixed with K-wires. A dorsal trough was then made between the scaphoid and the lunate. The proximal half of the CH ligament was harvested with attached bone from the capitate and hamate (CH bone-ligament-bone), inset into the SL trough, and fixed firmly with 1.2-mm diameter titanium screws in the scaphoid and lunate, respectively. Results The VAS improved from 77 preoperatively to 12 postoperatively. The average wrist extension/flexion was 74°/60°. There was no ossification of the reconstructed SL at the final follow-up. The SL gap improved from an average of 4.8 mm to an average of 2.1 mm, and the SL angle changed from 67° to 55°. The MMWS improved to 82 points postoperatively from a preoperative average of 47 with eight excellent, five good, and two fair results.

Outcomes of Capitohamate Bone-Ligament-Bone Grafts for Scapholunate Injury

Purpose In an attempt to restore natural carpal kinematics more closely, bone-ligament-bone (BLB) grafts have been described for treating scapholunate (SL) injury. In this article we report the long-term results of capitohamate BLB autograft for the treatment of SL dissociation. Methods The medical records of patients treated with capitohamate BLB grafts for SL dissociation were retrospectively reviewed. Twenty-three patients were available for evaluation. Patients were sent a Disabilities of the Arm, Shoulder, and Hand (DASH) and a Patient-Rated Wrist Evaluation (PRWE) questionnaire and returned for exam. Thirteen patients returned the questionnaire, and 12 wrists were examined. Range of motion, grip strength, pain, complications, return to work, and radiographic parameters were documented. Results The average length of follow-up evaluation was 9.2 years. The average SL gap was 4.5 mm preoperatively and 3.6 mm at final follow-up. The average SL angle was 70 degrees preoperatively and 73 degrees at final follow-up. There was no statistically significant difference in preoperative versus postoperative flexion, extension, radial deviation, ulnar deviation, or grip strength. The average postoperative visual analog scale (VAS) score was 1.25 at rest and 3.58 with activity. The average Mayo Wrist Score was 66.8 preoperatively and 70.9 postoperatively (p = 0.158). The average postoperative PRWE was 20.5, and average postoperative DASH was 15.1. At final follow-up, four patients had no radiographic evidence of arthritis. Two patients had evidence of early-stage radiocarpal arthritis, four had evidence of midcarpal arthritis, and two had radiographic evidence of mild scaphotrapeziotrapezoid arthritis. One patient required a salvage procedure with four-corner fusion. Discussion BLB reconstruction can be used to treat SL instability. At final follow-up, the majority of patients did not worsen clinically or functionally or require secondary salvage procedures; however, radiologic progression of arthritis was not prevented. These outcomes are comparable to midterm results of other SL reconstructive options; thus, we have abandoned this technique for other less technically demanding procedures. 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.

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.

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.

[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.

Differential strain of the axially loaded scapholunate interosseus ligament

PURPOSE

To directly measure strain changes in the scapholunate ligament via magnetic resonance imaging (MRI) when axially loading the wrist in the neutral and extended positions.

METHODS

Six asymptomatic male volunteers without known history of previous wrist injury were enrolled in this MRI-based study. Each subject underwent 3 MRI scans in a 3T scanner: in resting neutral position, in neutral with axial load applied, and in extension with axial load applied. Axial load was applied via extension of an elastic band with known force/elongation curve. We analyzed images and converted them to 3-dimensional stereolithographs. Attachment points of the palmar, proximal, and dorsal sections of the scapholunate interosseus ligament (SLIL) were identified. The lengths of the resulting vectors were recorded for each position. Strain, defined as change in length divided by original length, was calculated for the axially loaded neutral and extended wrists. We used the Bonferroni adjusted multiple comparisons from an analysis of variance model, with statistical significance defined as p < .05.

RESULTS

Strains were significantly greater in the palmar (p = .02) and proximal (p = .01) subregions of the SLIL in loaded extension versus loaded neutral positions. In contrast, the strain on the dorsal component in extension was not statistically greater than in the neutral position (p = .45). Axial load in neutral resulted in minimal strain of all 3 components of the SLIL complex, and these were not significantly different from each other (p > .99). With extension, the strains of the palmar (p = .03) and proximal (p = .006) regions were statistically greater than that of the dorsal component.

CONCLUSIONS

In extension, strain is greatest in the palmar and proximal portions of the intact SLIL. Axial load in neutral applies minimal strain to the SLIL complex. Avoiding axial loading in extension and encouraging loading in neutral position may allow for decreased injury and more effective healing of the scapholunate ligament.

Arthrodesis for chronic static scapholunate dissociation: a prospective study in 12 patients

Twelve patients had limited arthrodesis between the scaphoid and the lunate for chronic static scapholunate dissociation using internal plate osteosynthesis. The median time between the injury and surgery was 50 months (range 9-180). They were followed up for a year postoperatively. Preoperative symptoms were pain, functional impairment, and restricted movement. During operation the scapholunate interosseous ligament was completely torn and the scaphoid malrotated in all patients. The range of motion was measured preoperatively and postoperatively, and the unaffected side used for control. For all patients except one postoperative extension, flexion, and radial deviation had considerably decreased. However, supination increased in seven of 12 patients postoperatively and so did pronation in seven of 12 patients. One patient (case 12) had an improved range of motion postoperatively in all directions. The mean grip strength was 76% of the unaffected side preoperatively, and has increased to 85% postoperatively. We found that bone healing was rare and most arthrodeses healed by a fibrous union. We found no correlation with preoperative arthrosis and clinical outcome. One patient had retired from work before operation because of back pain and one because of age. Two patients had taken early retirement because of wrist pain, and one patient was still on sick-leave at the follow-up a year postoperatively. Five patients returned to full-time work and two patients to part-time work. Four patients were on long-term sick-leave preoperatively and three of them returned to their previous occupations. Analysis of the patients' subjective outcome (including pain and functional scores) showed overall satisfaction, and objective data show that scapholunate arthrodesis for chronic static scapholunate dissociation provides substantial improvement over the preoperative condition.

[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.

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.

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.

Outcomes of dorsal capsulodesis and tenodesis for treatment of scapholunate instability

PURPOSE

The ideal treatment for scapholunate (SL) instability has not yet been established. This study examined the results of 2 procedures for the primary treatment for chronic SL dissociation of dorsal capsulodesis and flexor carpi radialis tenodesis.

METHODS

A retrospective analysis was conducted that examined dorsal capsulodesis and tenodesis procedures performed for chronic SL instability between January 1995 and February of 2003. Twenty-nine patients were identified with isolated chronic SL instability. Of the 29 patients, 14 had a dorsal capsulodesis procedure and 15 had a tenodesis procedure. The follow-up period averaged 38 months in the capsulodesis group and 36 months in the tenodesis group. Results were reviewed clinically and radiographically. Groups were compared with a Student t test.

RESULTS

Postoperative wrist motion decreased in both groups after surgery. Final wrist range of motion was 64% of the unaffected side in the capsulodesis group and 63% of the unaffected side in the tenodesis group. Postoperative grip strength remained unchanged in both groups; grip strength measured 91% of the unaffected side in the capsulodesis group and 87% of the unaffected side in the tenodesis group. The average Mayo wrist scores were 77 in the capsulodesis group and 74 in the tenodesis group. One frank failure occurred in the tenodesis group resulting in a wrist fusion. There was no statistical difference in the overall wrist motion, grip strength, or wrist scores between the capsulodesis and tenodesis groups.

CONCLUSIONS

Dorsal capsulodesis and tenodesis provided improvement in symptoms for patients with chronic SL instability. Both procedures appear to provide similar results in the treatment of this difficult problem.

In vivo elongation of the palmar and dorsal scapholunate interosseous ligament

PURPOSE

To investigate the elongation of the palmar and dorsal subregions of the scapholunate interosseous ligament (SLIL) in healthy human subjects throughout a complete range of wrist motion.

METHODS

The 3-dimensional in vivo kinematics of the scaphoid and lunate were determined in both wrists of 13 female and 13 male volunteers from computed tomography volume images. For each wrist the palmar and dorsal insertions of the SLIL were identified on reconstructed surface models of the scaphoid and lunate. The interbone distances between the palmar and dorsal sites were calculated for the neutral wrist position. Elongations were then calculated after applying the 3-dimensional kinematics to the scaphoid and lunate. A multiple linear regression model was used to determine if elongations varied significantly as a function of wrist flexion/extension and radioulnar deviation.

RESULTS

From pure wrist extension to pure wrist flexion, the fibers of the SLIL at the palmar insertion site increased significantly, from 29% shortening to 27% elongation, and the dorsal insertion decreased from 26% to 4% shortening with respect to the fiber lengths in the neutral position. From pure radial deviation to pure ulnar deviation, the elongation of the palmar insertion significantly decreased from 9% elongation to 21% shortening. There was no notable change in dorsal elongation with wrist radioulnar deviation. The multiple linear regression model predicted that there would be minimal elongation of the palmar and dorsal fibers at the wrist position along the dart thrower's path from radial extension to ulnar flexion.

CONCLUSIONS

In vivo elongation of the palmar and dorsal fibers of the SLIL varied with wrist position. The palmar fibers lengthened and the dorsal fibers shortened with wrist flexion and the opposite occurred with wrist extension. Scapholunate interosseous ligament elongation was minimal as the wrist was positioned along the dart thrower's path.

Capsulodesis for the treatment of chronic scapholunate instability

PURPOSE

Scapholunate (SL) instability is the most common form of carpal instability. The treatment of this disorder is challenging and varying treatment options have been described. The purpose of this study was to examine the intermediate-term results of dorsal capsulodesis for cases of chronic SL dissociation.

METHODS

A retrospective analysis was conducted that examined all dorsal capsulodesis procedures performed for chronic SL dissociation between January of 1990 and February of 2000. Wrist pain had to be present for greater than 3 months. Patients had to have a minimum follow-up period of 2 years for inclusion in the study. Thirty-one patients were identified with isolated chronic SL dissociation. Of the 31 patients 18 had dynamic carpal instability and 13 had static carpal instability. The time from injury to surgery averaged 20 months. The follow-up period averaged 54 months (range, 24-96 mo). All patients had a dorsal capsulodesis procedure using either a Blatt or Mayo technique. Results were reviewed clinically and radiologically. Static and dynamic groups were compared with a Student t test.

RESULTS

There was a 20% decrease in wrist motion after capsulodesis. There was no improvement in grip strength after surgery. Most patients had improvement in pain but only 2 patients were completely pain free. Radiographically the SL gap increased over time from 2.7 mm before surgery to 3.9 mm at the final follow-up evaluation. The SL angle also increased from 56 degrees before surgery to 62 degrees on final follow-up evaluation. There was no statistical difference in overall wrist motion, grip strength, or wrist score between the dynamic and static groups. The time to surgery and age had no significant effect on overall outcome.

CONCLUSIONS

Dorsal capsulodesis provided pain relief for patients with both dynamic and static SL instability. Although pain was improved it was not completely resolved in the majority of cases. From a radiographic perspective dorsal capsulodesis did not provide maintenance of carpal alignment in cases of chronic SL dissociation.

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.

Osteoligamentoplasty and limited dorsal capsulodesis for chronic scapholunate dissociation

Treatment of chronic scapholunate dissociation remains unsatisfactory. As the dorsal part of scapholunate interosseous ligament (SLIL) seems to be the "critical corner" of the scapholunate stability, its replacement by an analogous structure could restore scapholunate stability. A procedure is described which combines reconstruction of the dorsal region of the SLIL by means of an osteoligamentous autograft, harvested at the carpus (dorsal trapezoidometacarpal II ligament) and limited dorsal capsulodesis. The limited dorsal capsulodesis is performed using the scaphotriquetral head of the dorsal intercarpal ligament left attached to the distal pole of the scaphoid and fixed with a bone anchor on the dorsal aspect of the lunate. The osteoligamentous autograft prevents scapholunate dissociation and dorsal scaphoid subluxation. The dorsal capsulodesis limits scaphoid flexion and allows synergistic scapholunate mobility. This combination should stabilize the scaphoid in the horizontal as well as sagittal planes. The advantages of this technique are: 1) a single incision; 2) replacement of a ligament by an analogous autograft; 3) faster healing by bone-to-bone apposition; 4) more anatomic and physiologic reconstruction. Three patients are presented to illustrate the technique.

Constraint and material properties of the subregions of the scapholunate interosseous ligament

The material and constraint properties of the dorsal, proximal, and palmar regions of the scapholunate ligament were studied using isolated bone-ligament-bone preparations from 24 adult intact cadaver wrists. Determinations of constraint to differential rotation and translation as well as failure strength were made using a servohydraulic testing machine incorporating an additional rotatory actuator. The dorsal region of the scapholunate ligament offered the greatest constraint to differential translation, while both the dorsal and palmar regions demonstrated statistically significant combined constraints to differential rotation between the scaphoid and lunate. The greatest yield strength was found in the dorsal region (260.3 N +/- 118.1 N), followed by the palmar region (117.9 N +/- 21.3 N) and the proximal region (62.7 N +/- 32.2 N).