Scaphoid proximal pole ejection in perilunate injury: a case report and pathophysiological hypothesis.

Isolated ejection of the scaphoid proximal pole in perilunate injuries is rare, with only 4 reports in the literature, and does not correspond to the biomechanical situations in the Herzberg or Mayfield classifications. Bone ejection incurs a risk of avascular necrosis despite good osteosynthesis, notably because of precarious vascularization. We present a case of scaphoid proximal pole ejection and a theoretical hypothesis of the biomechanics of this injury. LEVEL OF EVIDENCE: 4.

Artrodesis de cuatro esquinas: análisis comparativo de técnica abierta versus técnica percutánea con asistencia artroscópica / Four-corner arthrodesis: comparative analysis of open surgery versus percutaneous technique with arthroscopic assistance

INTRODUCCIÓN: La artrodesis de cuatro esquinas es una técnica de salvataje para los pacientes con artrosis avanzada del carpo. Los objetivos quirúrgicos son disminuir el dolor y mantener cierto movimiento de la muñeca. En el último tiempo, se han descrito técnicas percutáneas con asistencia artroscópica que han logrado resultados favorables, a pesar de que la técnica abierta sigue siendo el gold estándar para realizar esa técnica quirúrgica. OBJETIVO: Comparar resultados funcionales y radiológicos en pacientes con muñecas con colapso avanzado escafolunar (scapholunate advanced collapse, SLAC) o colapso avanzado en la pseudoartrosis del escafoides (scaphoid nonunion advanced collapse, SNAC) operados con técnica quirúrgica abierta versus técnica percutánea con asistencia artroscópica. MATERIALES Y MÉTODOS: Estudio retrospectivo tipo caso-control, de fichas clínicas e imagenología de pacientes con artrosis avanzada del carpo operados con técnica percutánea y asistencia artroscópica y cirugía abierta. Se estudian variables demográficas, dolor mediante la Escala Visual Analógica (EVA), función en rangos de movilidad, tiempo de consolidación, y corrección del ángulo capitolunar. Se describe la técnica quirúrgica de la cirugía abierta y la cirugía percutánea con asistencia artroscópica. RESULTADOS: Se estudiaron 22 pacientes del sexo masculino con edad promedio de 32,5 años. Había 13 pacientes en el grupo de casos (técnica percutánea con asistencia artroscópica) y 9 pacientes en el grupo de controles (técnica abierta). El dolor en la EVA al momento del egreso hospitalario fue de 3 para los casos y de 5 para los controles (p » 0,008), y a los 30 días del postoperatorio, fue de 0 y 3 respectivamente (p » 0,00). Los rangos de extensión y flexión fueron de 52,6° y 38,7° para los casos y de 35,7° y 32,4° para los controles (p » 0,1119 y 0,0016, respectivamente). El ángulo capitolunar fue de 10° para los controles y de 5° para los casos (p » 0,0008). El tiempo de consolidación fue de 8,8 semanas para los casos y de 12,5 semanas para los controles (p » 0,039). DISCUSIÓN: Tanto la técnica percutánea con asistencia artroscópica cuanto la cirugía abierta para realizar una artrodesis de cuatro esquinas son técnicas reproducibles y efectivas en lograr consolidación, disminución del dolor, y mantenimiento de rangos de movimiento en la muñeca. CONCLUSIÓN: En el presente trabajo se demuestran mejores promedios de los parámetros evaluados con la técnica percutánea que con la cirugía abierta; sin embargo, es necesario realizar estudios prospectivos para realizar una recomendación con respecto a la técnica quirúrgica de elección.

INTRODUCTION: Four-corner arthrodesis is a salvage technique for patients with advanced carpal osteoarthritis. This procedure aims to reduce pain and preserve wrist motion. Even though percutaneous techniques with arthroscopic assistance reportedly have favorable outcomes and the advantages of minimal invasiveness, open surgery remains the gold standard for four-corner arthrodesis. OBJECTIVE: The present study aims to compare the functional and radiological outcomes of patients with scapholunate advanced collapse (SLAC) or scaphoid nonunion advanced collapse (SNAC) submitted to open surgery versus percutaneous surgery with arthroscopic assistance. MATERIALS AND METHODS: Retrospective case-control study of clinical records and radiological images of patients with advanced carpal osteoarthritis submitted to percutaneous surgery with arthroscopic assistance versus open surgery. Demographic variables, pain score using the visual analog scale (VAS), function ranges of motion, time until consolidation, and correction of the capitolunate angle were analyzed. Both techniques are described. RESULTS: In total, 22 male patients with an average age of 32.5 years were studied, including 13 patients from the case group (percutaneous surgery with arthroscopic assistance) and 9 patients from the control group (open surgery). The VAS score for pain at discharge was of 3 for the cases and of 5 for the controls (p » 0.008); 30 days postoperatively, it was of 0 and 3 respectively (p » 0.00). The ranges of extension and flexion were of 52.6° and 38.7° for the case group, and of 35.7° and 32.4° for the control group (p » 0.119 and 0.0016 respectively). The capitolunate angle was of 10° for the controls and of 5° for the cases (p » 0.0008). The time until consolidation was of 8.8 weeks for the cases and of 12.5 weeks for the controls (p » 0.039). DISCUSSION: Both four-corner arthrodesis techniques are reproducible and effective in achieving consolidation, pain reduction and preservation of wrist motion. CONCLUSION: The present study demonstrates the superiority of the percutaneous technique with arthroscopic assistance over open surgery. Further prospective studies are required for an adequate recommendation.

Wrist movements induce torque and lever force in the scaphoid: an ex vivo study.

PURPOSE: We hypothesised that intercarpal K-wire fixation of adjacent carpal bones would reduce torque and lever force within a fractured scaphoid bone. METHODS: In eight cadaver wrists, a scaphoid osteotomy was stabilised using a locking nail, which also functioned as a sensor to measure isometric torque and lever forces between the fragments. The wrist was moved through 80% of full range of motion (ROM) to generate torque and force within the scaphoid. Testing was performed with and without loading of the wrist and K-wire stabilisation of the adjacent carpal bones. RESULTS: Average torque and lever force values were 49.6 ± 25.1 Nmm and 3.5 ± 0.9 N during extension and 41 ± 26.7 Nmm and 8.1 ± 2.8 N during flexion. Torque and lever force did not depend on scaphoid size, individual wrist ROM, or deviations of the sensor versus the anatomic axis. K-wire fixation did not produce significant changes in average torque and lever force values except with wrist radial abduction (P = 0.0485). Other than wrist extension, torque direction was not predictable. CONCLUSION: In unstable scaphoid fractures, we suggest securing rotational stability with selected implants for functional postoperative care. Wrist ROM within 20% extension and radial abduction to 50% flexion limit torque and lever force exacerbation between scaphoid fragments.

Functional outcomes after surgical treatment of isolated scaphotrapeziotrapezoid osteoarthritis: Retrospective single-center 24-case series.

Isolated scaphotrapeziotrapezoid (STT) osteoarthritis has functional consequences on the wrist. The main objective of our study was to evaluate the functional outcomes of patients managed surgically during the last 12 years at the Toulouse University Hospital, regardless of the surgical technique used, for isolated STT osteoarthritis. We performed a single-center retrospective observational study using the CCAM database. The inclusion criteria were patients treated surgically for isolated STT osteoarthritis who did not respond to conservative treatment, with at least 6 months of clinical and radiological follow-up. Twenty-four patients were treated between 2006 and 2018. Partial arthroplasty of the distal pole of the scaphoid with or without interposition and total trapeziectomy had been performed on these patients. The mean follow-up was 79±46.8 months. The wrist range of motion (ROM) and the Kapandji score were not significantly reduced postoperatively. The mean postoperative QuickDASH score was 29.15±8.46. The mean pain assessed using a visual analog scale was 6.6±1.17 preoperatively versus 1.25±1.51 postoperatively (P=0.003). Statistical subgroup analysis found no predictive factor for a better postoperative QuickDASH score, and no surgical technique was superior at halting the progression of intracarpal misalignment and postoperative ROM. Surgical treatment of isolated STT osteoarthritis resistant to conservative treatment leads to significant functional improvement, particularly in terms of pain, without altering the wrist's overall mobility.

Nickel-titanium arched shape-memory alloy connector combined with bone grafting in the treatment of scaphoid nonunion.

PURPOSE: To summarize the techniques and clinical effectiveness in treating scaphoid nonunion with nickel-titanium (Ni-Ti) arched shape-memory alloy connector in combination with autologous iliac bone grafts. METHODS: This study retrospectively analyzed 18 scaphoid nonunion cases treated with arched connectors with autologous iliac bone grafts. Based on scaphoid nonunion, 2 cases were classified as type II (fibrous union), 4 cases as type III (mild sclerotic union), 6 cases as type IV (moderate resorption and sclerosis), 5 cases as type V (severe bone resorption and sclerosis), and 1 case as type VI (pseudarthrosis formation). At the first 4, 8 and 12 weeks after the surgery, wrist anteroposterior, lateral X-ray were obtained, respectively, to evaluate bone healing. Patients who had not yet reached the standard of healing at 12 weeks after surgery would continue to receive additional appointments for follow-up visits, such as 14 weeks, 16 weeks, 18 weeks after surgery, until their imaging studies had achieved satisfactory bone healing. Clinical effectiveness was evaluated comprehensively, based on bone union time, Mayo wrist score, and visual analog pain score. RESULTS: All 18 patients achieved satisfactory reduction and fixation with a mean union time of 4.2 months. Preoperative Mayo wrist score averaged 57.4 and average final postoperative follow-up was 91.4. On the other hand, mean preoperative VAS score was 6.8, and final postoperative follow-up average was 1.6. Mayo wrist score of the overall treatment effectiveness was excellent (90-100) in 12 cases, good (80-90) in 5 cases, and acceptable (60-80) in 1 case with zero poor (below 60) cases observed. Statistical analysis suggested that a statistically significant improvement in fracture healing, wrist function recovery and visual analog pain after surgery when compared to the scores of the patients before surgery. CONCLUSION: Using Ni-Ti arched shape-memory alloy connector in combination with autologous bone grafting provided a new modality to treat scaphoid nonunions in a less traumatic, convenient to operate and satisfactory manner in treatment outcomes, and thus is worthy of further application.

Wrist kinetics after scaphoidectomy.

BACKGROUND: The scaphoid cannot be excised without generating substantial carpal dysfunction. The extent and nature of such a destabilizing procedure, however, has never been properly studied in the laboratory. METHODS: We used a six-degrees-of-freedom motion tracking device to quantify the changes in carpal alignment produced by isometric simultaneous loading of five wrist motor tendons in 12 fresh normal cadaver arms, before and after excising the entire scaphoid. FINDINGS: In the intact wrist, tendon loading consistently extended and supinated the capitate while flexing the triquetrum. After scaphoidectomy, the opposite rotations were always found: the capitate collapsed into flexion and pronation, whereas the triquetrum migrated proximally, while extending and radial deviating. All these changes were statistically significant. INTERPRETATION: Unless it is supplemented by some sort of midcarpal stabilization, scaphoidectomy alone is much too aggressive as a procedure to be considered a treatment option for wrist osteoarthritis. LEVEL OF EVIDENCE: Laboratory study. Not applicable.

Bilateral scapholunate widening may have a nontraumatic aetiology and progress to carpal instability and osteoarthritis with advancing age.

It was hypothesized that bilateral widening of the scapholunate gap is relatively common in the absence of trauma and that it progresses to radiological carpal instability and scapholunate advanced collapse. Electronic files of 1000 patients with bilateral X-rays were studied in retrospect. Wide scapholunate gaps were bilaterally present in 67 and unilaterally in 51 patients. Scapholunate advanced collapse was observed in 26 patients; in nine it was in both wrists. A trauma was recorded in less than half of the patients with a bilateral wide scapholunate gap. Patients with bilateral wide gaps were younger if signs of carpal instability or osteoarthritis were absent. Bilateral scapholunate widening may not be caused by an acute trauma, but may lead to carpal instability and degenerative changes with advancing age.

Interfragmentary Compression Forces Vary Based on Scaphoid Bone Screw Type and Fracture Location.

BACKGROUND: The objective of this study was to determine the interfragmentary compression forces generated in a foam model as a function of headless compression screw type (fully threaded and central threadless) and fracture location. METHODS: Eighty-eight polyurethane foam models were fixed across a simulated transverse fracture with either a fully threaded screw or a central threadless screw. The location of the transverse fracture varied along the length of the foam model in 2 mm increments for 11 fracture locations. The force generated at the fracture site upon fixation was utilized to determine the interfragmentary compression. Interfragmentary compression was compared using a paired t test and 2-way analysis of variance, with significance set at P < .05. RESULTS: Interfragmentary compression was found to vary based on fracture location and screw type. The fully threaded screw generated significantly greater compression for fracture locations at 12 mm and 18 mm from the top edge of the foam model, while the central threadless screw generated significantly greater compression for fractures located 2 mm from the top edge of the foam model. CONCLUSIONS: The central threadless screw and the fully threaded screw had different fracture locations where maximum compression force occurred. The fully threaded screw generated greater compression force toward the screw center due to greater thread purchase. However, the central threadless screw generated greater compression at the most proximal fracture location due to its greater thread pitch toward the screw head. Maximizing interfragmentary compression may aid in reducing nonunion rates associated with the internal fixation of proximal scaphoid fractures.

Comparison of Radiographic and Intraoperative Visual Assessment of Scaphotrapezoid Joint Arthritis in Patients With End-Stage Carpometacarpal Arthritis of the Thumb Base.

Background: The purpose of this investigation is to compare the radiographic and intraoperative assessment of scaphotrapezoid (ST) joint arthritis in patients with end-stage carpometacarpal (CMC) arthritis of the thumb base. We aim to define the incidence of ST arthritis in this population and determine whether radiographic features such as lunate morphology, dorsal intercalated segment instability (DISI), and scapholunate (SL) diastasis are associated with the incidence of ST arthritis. Methods: We retrospectively reviewed consecutive patients with end-stage CMC arthritis of the thumb treated operatively with trapeziectomy. Preoperative wrist radiographs were reviewed, and the presence of ST arthritis was determined using the Sodha classification. Lunate morphology, DISI, and SL diastasis were noted. Intraoperative grading of ST arthritis was assessed using a modified Brown classification. The specificity and sensitivity of radiographic assessment was compared with the gold standard of intraoperative direct visualization. Results: In total, 302 thumbs met inclusion criteria. End-stage ST joint arthritis determined by intraoperative visual inspection was noted in 31% of cases. No radiographic or demographic variables were found to be risk factors for ST arthritis. Plain radiographs were 47% sensitive and 94% specific in their ability to detect end-stage ST joint arthritis. Conclusions: We report a 31% incidence of end-stage ST joint arthritis in surgically treated patients with CMC arthritis based on visual inspection which is lower than previous literature. Wrist radiographs demonstrate a 47% sensitivity and 94% specificity in predicting end-stage ST joint arthritis. It is imperative to directly visualize the ST joint after trapeziectomy, as radiographs demonstrate poor sensitivity.

Biomechanical Strength of Retrograde Fixation in Proximal Third Scaphoid Fractures.

Background: Current techniques for fixation of proximal pole scaphoid fractures utilize antegrade fixation via a dorsal approach endangering the delicate vascular supply of the dorsal scaphoid. Volar and dorsal approaches demonstrate equivalent clinical outcomes in scaphoid wrist fractures, but no study has evaluated the biomechanical strength for fractures of the proximal pole. This study compares biomechanical strength of antegrade and retrograde fixation for fractures of the proximal pole of the scaphoid. Methods: A simulated proximal pole scaphoid fracture was produced in 22 matched cadaveric scaphoids, which were then assigned randomly to either antegrade or retrograde fixation with a cannulated headless compression screw. Cyclic loading and load to failure testing were performed and screw length, number of cycles, and maximum load sustained were recorded. Results: There were no significant differences in average screw length (25.5 mm vs 25.6 mm, P = .934), average number of cyclic loading cycles (3738 vs 3847, P = .552), average load to failure (348 N vs 371 N, P = .357), and number of catastrophic failures observed between the antegrade and retrograde fixation groups (3 in each). Practical equivalence between the 2 groups was calculated and the 2 groups were demonstrated to be practically equivalent (upper threshold P = .010). Conclusions: For this model of proximal pole scaphoid wrist fractures, antegrade and retrograde screw configuration have been proven to be equivalent in terms of biomechanical strength. With further clinical study, we hope surgeons will be able to make their decision for fixation technique based on approaches to bone grafting, concern for tenuous blood supply, and surgeon preference without fear of poor biomechanical properties.

Arthroscopy-assisted treatment of scaphoid and lunate cysts: Clinical evaluation of 7 cases.

Intraosseous cysts of the carpus are relatively common benign tumors. They are often discovered by chance and can cause wrist pain thereby requiring appropriate management. While conventional open surgical treatment leads to good results, it has certain disadvantages, the main one being postoperative stiffness. Arthroscopic treatment has been proposed as an alternative for lunate cysts. The present study consisted in evaluating the feasibility and outcomes of arthroscopic treatment for lunate and scaphoid cysts. The main objective was to evaluate the postoperative clinical outcomes at 3 and 18 months. The secondary objective was to evaluate the integration of a cancellous bone graft. We conducted a retrospective study of eight patients who underwent surgery between April 2010 and October 2016. Of these, four had a lunate cyst and four had a scaphoid cyst; all cysts had a dorsal operculum. Patients had disabling wrist pain that did not respond to conservative treatment. The diagnosis was confirmed by radiography and either a CT scan or an MRI. Curettage and cancellous grafts were performed under arthroscopic control. The technique was carried out successfully in all cases. One patient was lost to follow-up. At 18 months, postoperative pain was rated at 1.28 on a visual analog scale. The grip strength (measured with a Jamar dynanometer) was 77% when compared to the contralateral side. There was an improvement in joint range of motion, with an average wrist flexion of 67.5° compared to 48.3° preoperatively and an average wrist extension of 71.5° compared to 47.6° preoperatively. The Patient-Rated Wrist Evaluation (PRWE) score decreased from 69.7 to 12.7, which was a significant decrease. A good integration of the cancellous graft was confirmed at 6 months in all cases by CT scan or MRI. Curettage with a cancellous graft of lunate and scaphoid cysts under arthroscopic control is a technique that allows surgeons to obtain satisfactory clinical results with good integration of the graft.

Force Required to Maintain Reduction of a Preexisting Scapholunate Dissociation.

PURPOSE: To determine the force required to maintain reduction of Geissler grade 4 scapholunate dissociations during physiological wrist motions. METHODS: Fresh-frozen cadaveric wrists with Geissler grade 4 scapholunate dissociations were identified by arthroscopy. Following reduction, a load cell was attached to measure the force across the scapholunate joint at a neutral position and during 4 different wrist motions re-created using a servohydraulic wrist simulator, including a large flexion-extension motion (FEM), small and large dart-thrower's motions (DTMs), and a large DTM with ulnar offset. RESULTS: Five wrists with isolated preexisting scapholunate interosseous ligament (SLIL) tears were analyzed. The force required to maintain reduction was significantly greater in extension than in flexion during the large FEM and large DTM with ulnar offset. The forces were significantly larger in this study of preexisting SLIL dissociations compared with results from a prior study of acutely sectioned SLILs. In addition, forces to maintain reduction during DTMs were significantly less than forces during FEMs. Finally, a set of 3 wrists with preexisting scapholunate and lunotriquetral interosseous ligament (LTIL) tears were identified and had significantly decreased forces to maintain reduction at maximum extension and had decreased maximal forces during a cycle of motion compared with the wrists with isolated SLIL tears. CONCLUSIONS: The forces required to maintain reduction of a Geissler grade 4 wrist are higher than forces after acutely sectioned SLIL. The forces are greater in extension than in flexion and less during the DTM compared with the FEM. Wrists with both SLIL and LTIL tears required less force to maintain reduction than those with isolated SLIL tears. CLINICAL RELEVANCE: This study helps determine the strength of reconstruction required to maintain reduction of a Geissler grade 4 scapholunate dissociation.

Scaphoid Nonunions.

Scaphoid nonunions are challenging injuries to manage and the optimal treatment algorithm continues to be debated. Most scaphoid fractures heal when appropriately treated; however, when nonunions occur, they require acute treatment to prevent future complications like scaphoid nonunion advanced collapse. Acute nonunion treatment technique depends on nonunion location, vascular status of the proximal pole, fracture malalignment, and pre-existing evidence of arthrosis. Bone grafting and vascular grafts are common in nonunion management. Chronic nonunions that have progressed to scaphoid nonunion advanced collapse often require a salvage procedure such as four corner fusions, proximal row carpectomy, or wrist fusion. Herein, we review the current literature regarding scaphoid nonunions with regards to their anatomy, natural history, classification, diagnostic imaging, surgical management, and clinical outcomes.

Treatment of chronic scapholunate dissociation with tenodesis: A systematic review.

Scapholunate (SL) instability is the most common dissociative carpal instability condition. It is the most frequent cause of wrist osteoarthritis, defined as scapholunate advanced collapse or SLAC wrist. Familiarity with the SL ligament complex is required to understand the various features of SL instability. Damage to the SL interosseous ligament is the main prerequisite for SL instability; however the extrinsic, palmar and dorsal ligaments of the carpus also come into play. When more than 6 weeks has passed since the initial injury event, SL instability is considered chronic because ligament healing is no longer possible. Before osteoarthritis sets in and when the SL instability is still reducible (scaphoid can be reverticalized), ligament reconstruction surgery is indicated. Since the end of the 1970s, various ligament reconstruction or tenodesis techniques have been described. These techniques are used in cases of chronic, dynamic or static reducible SL instability, when no repairable ligament stump and no chondral lesions are present. The aim is to correct the SL instability using a free or pedicled tendon graft to reduce pain while limiting the loss of mobility and protecting against osteoarthritis-related collapse in the long-term. We will perform a systematic review of the various tenodesis techniques available in the literature.

The effect of screw trajectory for the reduction and association of the scaphoid and lunate (RASL) procedure: a biomechanical analysis.

The purpose of this study was to determine if screw placement in the reduction and association of the scaphoid and the lunate (RASL) procedure affected the ability of the scapholunate joint to withstand force. After completely disrupting of the scapholunate ligament in 29 fresh-frozen cadaveric wrists, we placed the RASL screw either distal or proximal to the lateral aspect of the dorsal ridge of the scaphoid and into the dorsal or volar aspect of the lunate. Specimens were subjected to repeated cycles of transcarpal axial force, mimicking clenched-fist loading, until failure. Screw placement distal to the lateral aspect of the dorsal scaphoid ridge was significantly associated with failure when examined manually, radiographically (1.8 vs. 0.5 mm) and using real-time motion capture (diastasis: 1.6 vs. 0.4 mm; Euler angle: 4.5 ° vs. 0.8 °). The lateral aspect of the dorsal ridge is a reliable radiographic landmark on the scaphoid and provides surgeons with a convenient starting point to achieve the most biomechanically stable RASL construct, and, therefore, enhances the potential for an optimal clinical outcome.

Impact of scapholunate dissociation on human wrist kinematics.

Neither the complex motions of the scapholunate joint, nor the kinematic changes that occur as a result of injury to it, are fully understood. We used electromagnetic tracking within affected bones to evaluate the physiologic motions in the planes of flexion and extension, and of radial and ulnar deviation of human cadaver wrists, before and after complete transection of the scapholunate ligaments. Despite individual variance between each wrist, we were able to establish a pattern in the changes that occurred after scapholunate ligament injury. During the motions examined, the scaphoid showed an increase in translational deviation in almost all motion axes. In contrast, the movement of the lunate seemed to be impaired, especially in radial-ulnar deviation.

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

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

Ten-Year Minimum Follow-Up of 4-Corner Fusion for SLAC and SNAC Wrist.

BACKGROUND: Scapholunate advanced collapse (SLAC) of the wrist is the most common degenerative condition of the wrist. Four-corner fusion (4CF) is performed as salvage surgery, though there is limited information on its long-term results. We hypothesized that 4CF is a durable surgery with good clinical long-term function. METHODS: A retrospective chart review of patients undergoing 4CF as well as an interview and recent radiographs were obtained. Patients with a follow-up period of less than 10 years were excluded. Long-term evaluation included standard wrist radiographs, wrist range of motion, and the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire. Radiographs were evaluated and described by the Kellgren-Lawrence classification. RESULTS: Four hundred eighty-nine wrists underwent a 4CF for SLAC wrist from 1982 to 2003. Twelve patients (15 wrists) were available for follow-up. Average age at surgery was 49.1 years (range, 25-67 years). Average follow-up postsurgery was 18 years (11-27). Scapholunate advanced collapse was the etiology in 13 wrists and scaphoid nonunion advanced collapse in 2 wrists. Average extension/flexion arc was 68.6° (0°-96°), and radial/ulnar deviation arc was 32.9° (0°-5°). QuickDASH scores averaged 7.8 (range, 0-32.5), with only 1 score above 16. Seventy-three percent of radiographs showed minimal to moderate joint destruction, and 27% showed severe joint destruction. CONCLUSIONS: Scaphoid excision and 4CF remains a reliable procedure for patients with advanced wrist arthritis. Functional results were good at long-term follow-up despite radiographic changes in the radiolunate joint in 73% of patients. Patient satisfaction was high, and functional impairment was low.

Evaluation of midcarpal capitate contact mechanics in normal, injured and post-operative wrists.

BACKGROUND: Scapholunate ligament injury is a commonly occurring carpal ligament injury. Pathology associated with scapholunate ligament injury depends on several factors such as the time after injury, type of injury (instability) and the development of osteoarthritis. The aim of this study was to investigate and compare contact mechanics in the lunocapitate and scaphocapitate joints in the normal, injured (scapholunate dissociation) and repaired (postoperative) wrist. METHODS: Four human subjects with scapholunate ligament dissociation participated in this study. MR images of normal (contralateral), injured and postoperative wrists were obtained during relaxed condition and during active light grasp. Relaxed MR images were used to construct model geometry (bones with cartilage) for the capitate, lunate and scaphoid. Kinematic transformations were obtained by using image registration between the unloaded and functionally loaded image sets. Joint surface contact mechanics were then calculated. FINDINGS: All contact measures (contact force, pressure, mean pressure and area) tended to increase with injury in both articulations. A significantly higher contact area was found in the injured scaphocapitate joint compared to normal. A significant increase in peak pressure was observed in the postoperative state compared to normal. INTERPRETATION: Injury to the scapholunate ligament increased contact measures, suggesting a risk for onset of osteoarthritis in both the scaphocapitate and lunocapitate joints. Surgical repair appeared to restore most measures of contact mechanics to near normal values, more so for the lunocapitate joint when compared to scaphocapitate joint. The elevated postoperative peak pressures indicate the difficulty to fully restore joint mechanics.