[Review of 10 patients with pure perilunate carpal dislocation at a minimum of 18years follow-up]. / Revue à 18ans de recul minimum, de 10 patients présentant une luxation périlunaire isolée du carpe.

OBJECTIVE: To evaluate, in long-term, the functional abilities and the occurrence of osteoarthritis in patients treated for a posterior perilunate carpal dislocation without bone lesion associated. PATIENTS AND METHOD: This was a monocentric retrospective observational study on patients operated on at the University Hospital of Guadeloupe for a posterior perilunate dislocation without bone lesion associated with a minimum of 18years of follow-up. Ten patients were included with a mean follow-up of 22.8years. The evaluation criteria were clinical (PRWE, QuickDASH, pain, grip strength, wrist joint mobility, Watson and Reagan tests, Cooney functional score) and radiographic (Gilula curves, carpal height, carpal ulnar translation, scapholunate and radiolunar angles, scapholunate and triquetro-lunar interlines in statics and dynamics, Herzberg's classification of complications). RESULTS: The average Cooney score was 67.5/100. Mean PRWE and QuickDASH scores were 33.9 and 24.8 respectively. The mean flexion-extension arc on the injured side was 71.5° (66.7% compared to the healthy side). Mean grip strength was 27kg (72.8% compared to the healthy side). The prevalence of osteoarthritis was 60%, with three A types, two A1 types, one B type and four B1 types according to Herzberg. CONCLUSION: The factors influencing the long-term prognosis are the initial displacement of the lunate, the quality of the reduction and the presence of chronic carpal instability, particularly scapholunate. The high prevalence of osteoarthritis in our series (60%) is apparently not correlated with the functional capacities of patients over the long term.

Evaluation of chronic perilunate dislocations: A comparative study of single-stage, two-stage ORIF, and salvage procedures.

OBJECTIVE: This study aims to evaluate the outcomes of open reduction and internal fixation (ORIF) for chronic perilunate dislocations using single-stage, two-stage, and salvage procedures. The study also compares these approaches with each other and with results from existing literature. METHODS: A total of 15 patients with chronic perilunate injuries from 2013 to 2019 were included in the study. Pre-operative and post-operative assessments were conducted using plain radiographs, with CT scans performed selectively for detailed morphology and fracture pattern analysis. Among the patients, 13 underwent ORIF, while 2 underwent salvage procedures. Among the ORIF cases, single-stage procedures were performed in 4 patients, and two-stage procedures in 9 patients. External fixators, including unilateral uniplanar external fixators (UUEF) and bilateral uniplanar external fixators (BUEF), were applied in 5 and 4 patients, respectively. Our methodology of treating chronic perilunate injuries has evolved over the years. We started with single stage ORIF then graduated to a two staged procedure initially using a external fixator as a carpal distractor applied only on the radial side and finally settling down with bilateral carpal distraction using external fixators both on the radial and ulnar sides. RESULTS: Among the 15 patients, 3 were lost to follow-up. Of these, one underwent four-corner fusion, while the remaining two had UUEF. The mean time interval between injury and surgery was 3.60 months. The post-operative mean scapholunate angle measured 52.46°, with a negative radio-lunate angle (indicating flexion) observed in two patients, while others showed a positive angle (indicating extension). Two cases exhibited nonunion and avascular necrosis (AVN) of the scaphoid, while one case presented with lunate AVN. Mid-carpal and radio-carpal arthritis was observed in 4 and 2 patients, respectively. Functional outcomes were evaluated using Mayo's wrist score categorized as good for two-stage BUEF cases and satisfactory for UUEF and single-stage procedures. CONCLUSION: Staged reduction utilizing the BUEF followed by open reduction has demonstrated superior outcomes when compared to UUEF, single-stage open reduction and salvage procedures. LEVEL OF EVIDENCE: 4.

A variant of perilunate dislocation: A case report and literature review.

Perilunate dislocation is a rare carpal dislocation, which are predominantly trans-styloid and trans-scaphoid. This type of fracture dislocation is seen due to axial loading of a hyperextended ulnar-deviated wrist. This can result in the disruption of the scapholunate, lunocapitate, and lunotriquetral ligaments. The lunate may dislocate volar or dorsal to the other carpal bones. Herein, we have reported a case of trans-styloid, trans-scaphoid perilunate fracture dislocation with carpal tunnel syndrome, which has never been reported in the literature. A 38-year-old construction worker presented with a swollen hand and signs of carpal tunnel syndrome. The patient was diagnosed with perilunate fracture dislocation after a through clinical and radiological assessment. The scaphoid had invaginated into the radial styloid and demonstrated a comminuted fracture pattern. Volar lunate displacement was identified, and the patient demonstrated signs of carpal tunnel syndrome, which is not a common presentation. Open reduction with ligament repair was performed to minimize jeopardizing the hand function. Spelt tea cup sign is a diagnostic for perilunate dislocation. Operative exploration and reduction is imperative for failed closed lunate dislocation reduction to minimizes ongoing soft tissue jeopardy. Moreover, carpal tunnel release is indicated in the present of symptomatic carpal tunnel syndrome. To our knowledge, only a few cases of trans-styloid, trans-scaphoid perilunate dislocation with neurological deficit have been reported.

Transradial Transcapitate Perilunotriquetral Coalition Fracture Dislocation.

Perilunate fracture dislocations (PLFDs) are uncommon, usually resulting from high-energy trauma. Several classification systems describe the patterns of injury seen, but there is still significant variation and patterns of injury that do not fit within these classifications continue to be described. Carpal coalitions are rare, mostly asymptomatic, and are, as a result, usually identified incidentally. We describe the case of a transradial transcapitate PLFD in a patient with a Minnaar Type 3 lunotriquetral coalition. Radiographic, clinical, and patient-reported outcomes are reported. When presented with a rare anatomical variation in the context of a complex injury, the importance of managing these complex injuries according to principles is highlighted.

Perilunate Fracture-Dislocation: Results at Mean Follow-Up of 7 Years after ORIF.

Background: Perilunate fracture-dislocations are frequently associated with a high risk of developing post-traumatic arthritis. Current studies indicate that during mid-term follow-ups, radiological signs of arthritis do not appear to correspond with functional score. The aim of this study was to assess the occurrence of posttraumatic arthritis and the wrist function after perilunate dislocations (PLD) and fracture dislocations at a mid-term follow-up of 7 years. Methods: We report the clinical and radiological outcomes of 17 wrists treated for PLD or fracture-dislocation by open reduction and internal fixation through a dorsal approach with dorsal ligament repair. Functional outcomes were evaluated using the short version of the Quick Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH), the Patient-Rated Wrist Evaluation questionnaire (PRWE) and the Mayo Wrist Score (MWS). Results of radiographs were assessed using the Herzberg Radiological Scoring Chart. Results: The MWS showed five excellent, five good, five fair and two poor results with an average score of 81%. Radiological analysis using the Herzberg classification revealed midcarpal and/or radiocarpal arthritis in 65% of cases, lunate collapse in 59% and an increase in the mean ulnar translocation ratio in 53% of the cases. Complications included one case of lunate osteonecrosis and one case of stage 3 scapholunate advanced collapse that required revision surgery. Conclusions: Although the clinical and functional outcomes are favourable at mid-term follow-up, radiological evaluation shows a progression towards osteoarthritis (OA). Further research is warranted to refine treatment strategies and investigate factors influencing the development of OA. Level of Evidence: Level IV (Therapeutic).

A deep learning-based algorithm for automatic detection of perilunate dislocation in frontal wrist radiographs.

This study proposes a Deep Learning algorithm to automatically detect perilunate dislocation in anteroposterior wrist radiographs. A total of 374 annotated radiographs, 345 normal and 29 pathological, of skeletally mature adolescents and adults aged ≥16 years were used to train, validate and test two YOLOv8 deep neural models. The training set included 245 normal and 15 pathological radiographs; the pathological training set was supplemented by 240 radiographs obtained by data augmentation. The test set comprised 30 normal and 10 pathological radiographs. The first model was used for detecting the carpal region, and the second for segmenting a region between Gilula's 2nd and 3rd arcs. The output of the segmentation model, trained multiple times with varying random initial parameter values and augmentations, was then assigned a probability of being normal or pathological through ensemble averaging. In the study dataset, the algorithm achieved an overall F1-score of 0.880: 0.928 in the normal subgroup, with 1.0 precision, and 0.833 in the pathological subgroup, with 1.0 recall (or sensitivity), demonstrating that diagnosis of perilunate dislocation can be improved by automatic analysis of anteroposterior radiographs. LEVEL OF EVIDENCE: : III.

Adjunctive Dorsal Spanning Plate Fixation in the Stabilization of Perilunate Dislocations.

PURPOSE: To compare the biomechanical properties of adjunctive dorsal spanning plate (DSP) fixation with traditional K-wire fixation of perilunate dislocations in a cadaveric model. METHODS: Fourteen fresh-frozen cadaveric wrists underwent simulated perilunate injury. The specimens were randomly allocated to either K-wire fixation versus K-wire and DSP fixation. Scapholunate (SL) ligament repair was performed in all specimens. The constructs were tested using a robot cyclically and to failure. Fluoroscopic images were obtained of the specimens prior to simulated injury, after fixation, after 10 and 100 loading cycles, and at construct failure. Differences in carpal alignment parameters (SL interval, SL angle, lunotriquetral interval, and capitolunate angle) and load to failure were recorded. RESULTS: There were no statistically significant differences between the two group's carpal alignment parameters after fixation. Specimens fixated with K-wires and DSP required significantly higher loads to achieve construct failure. The only significant difference between the two groups' carpal alignment parameters was SL interval change at failure. CONCLUSIONS: Compared with K-wire fixation alone, adjunctive DSP fixation resulted in significantly increased loads to failure and decreased change in SL interval at the time of failure. CLINICAL RELEVANCE: Adjunctive DSP may be a useful technique in the polytraumatized patient in whom providing back a weight-bearing extremity may be advantageous in the rehabilitation process.

[Trans-scapho-perilunar fracture-dislocation: a case report]. / Fractura-luxación transescafo-perilunar: reporte de un caso clínico.

Trans-scaphoid perilunate fractures-dislocations are rare injuries caused by high-energy trauma of the wrist. Diagnosis is based on medical history, physical examination, and tools such as radiographs, computed tomography scan, and magnetic resonance imaging. Early treatment consists of closed reduction and casting to stabilize the limb. Definitive treatment is surgical and includes bone and soft tissue repair. A case of trans-scaphoid perilunate fracture-dislocation is presented, along with diagnosis, management and outcome.

Las fracturas-luxaciones transescafo-perilunares son lesiones infrecuentes causadas por impactos de alta energía hacia la muñeca. El diagnóstico se basa en la historia clínica, exploración física y herramientas como la radiografía, la tomografía computarizada y la resonancia magnética. El manejo inmediato consiste en una reducción cerrada e inmovilización para estabilizar la extremidad. El tratamiento definitivo es de carácter quirúrgico e incluye la reparación ósea y de tejidos blandos. Se presenta un caso de fractura-luxación transescafo-perilunar, su diagnóstico, manejo y evolución.

Open Dislocation of the Lunate and Triquetrum: A Case Report.

The Mayfield sequence of progressive perilunar instability is commonly encountered. A reverse-perilunate sequence has also been described, where forces are transmitted from the ulnar wrist, resulting in progressive disruption of the ulnocarpal and lunotriquetral intervals. A concomitant dislocation of both the lunate and triquetrum together is a rare injury and has not been reproduced in cadaver models nor widely encountered in clinical cases. We report a rare case of an open volar dislocation of the lunate and triquetrum, and outline the management principles and outcomes in our patient. This case highlights that not all perilunar injuries occur in the conventional sequence. Differing paths of force transmission may result in atypical patterns of carpal disruption. Nonetheless, the broad management principles are similar. Achieving carpal reduction and stabilization, soft-tissue coverage, and early rehabilitation results in reasonable patient outcomes.

Surgical management and functional outcomes of perilunate dislocations and fracture dislocations through the dorsal approach.

BACKGROUND: Perilunate dislocations and perilunate fracture dislocations (PLD/PLFDs) are rare injuries of the wrist, with surgical management leading to acceptable functional results. PURPOSE: The purpose of this study was to assess the functional outcomes of the patients of our department who were treated with surgical management of PLDs/PLFDs through dorsal approach, as well as to report any complications on their follow-up. PATIENTS AND METHODS: In this retrospective study, 52 patients with PLD/PLFD, fulfilling the inclusion and exclusion criteria of the study, underwent surgical management of their injury. All patients were followed up at 6 weeks, 12 weeks, 6 months, 1 year postoperatively with radiographic imaging as well as functional scores measured with the modified mayo wrist score and the QuickDASH questionnaire. RESULTS: The mean postoperative modified Mayo score was 76.8 ± 8.8 and the mean QuickDASH score was 1.52 ± 2.18. Of the 52 cases, 20% had excellent results, 42% had good results, 29% had fair results and 9% had poor results as per the modified Mayo wrist score. No patient signed any symptoms of median nerve neuropathy. CONCLUSION: In conclusion, open reduction and internal fixation through dorsal approach is a reliable technique to manage perilunate injuries in spite of radiological evidence of wrist arthritis, as it also provides consistently good results in terms of functional outcomes. LEVEL OF EVIDENCE IV: Retrospective case series study.

Perilunate Dislocations: Cadaveric Model K-Wire Versus Compression Staple Fixation.

Purpose: Repair of perilunate dislocations requires stabilization of the carpal bones, although there is limited research on the preferred method(s) of stabilization. We compared the biomechanical characteristics of K-wire versus staple fixation of scapholunate (SL) and lunotriquetral (LT) intervals in the wrist. Methods: After creating a grade IV instability model, 20 cadaver wrists were randomized into 2 stabilization model groups using K-wires or surgical staples across the SL and LT intervals. For each ligament, two K-wires or one surgical staple was used to stabilize the proximal carpal row. Each wrist was loaded with 15 N of force and cycled 5,000 times at an angular velocity of 10 rpm. Displacement between bones was measured at different cycles (10, 100, 500, 1,000, 2,000, 3,000, 4,000, and 5,000). A t test was used for comparisons. Results: For the LT K-wire group, the average displacement at 10 cycles was 0.08 mm, and at 5,000 cycles, 0.163 mm. For the SL K-wire group, the average displacement at 10 cycles was 0.025 mm, and at 5,000 cycles, 0.129 mm. For the LT and SL staple fixation models, the average shifts at 10 cycles were 0.029 and 0.063 mm, and at 5,000 cycles, 0.098 and 0.176 mm, respectively. No significant difference between the fixation models was found at any interval. Notably, in each group, a similar number of small outliers with higher amounts of displacement was observed. Conclusions: Either K-wire or surgical staple stabilization is suitable for perilunate dislocations. The surgical method should be selected based on patient-specific circumstances and the provider's judgment. Type of study/level of evidence: Therapeutic III.

Volar Lunate Dislocation: A Case Report.

Introduction: Perilunate dislocations are rare high-energy injuries which may often have the potential to cause lifelong disability of the wrist if not addressed optimally. Hence, early recognition, diagnosis, and intervention are of paramount importance in the restoring function and prevention of morbidity. Lunate dislocations are the fourth and last stage of perilunate dislocations being extremely rare, with volar dislocations representing <3% of perilunate dislocations. Case Report: A 24-year-old man suffered from an alleged history of fall from a bike on an outstretched hand following which he developed complaints of pain and swelling in the right wrist. On examination, the patient has relative sensory loss over the lateral half of the palm with no vascular deficit. An accurate range of motion could not be documented due to severe pain. Standard digital X-rays revealed lunate displaced and angulated volarly with a typical "spilled teacup" appearance along with radial and ulnar styloid fractures. Management: The patient was initially given an attempt of closed reduction which was not successful and was followed with open reduction and internal fixation with both volar and dorsal approach with Kirschner wires. The patient's wrist was immobilized for 6 weeks with below elbow cast with the removal of k wires at 8 weeks after which wrist ROM exercises were started. Results: The patient was followed up for 6 months and now has a functional range of motion of the wrist with no sensory deficit and is able to continue with his profession as a car mechanic. Conclusion: Mayfield progression Stage 4 perilunate dislocations are uncommon with a poor prognosis if not addressed timely. Hence, these injuries need to be identified early and optimally managed with surgical intervention for a favorable outcome.

Arthroscopic Volar Capsuloligamentous Reattachment and Reinforcement to Bone.

Background: Injuries of the volar ligaments of the wrist are not uncommon, but their arthroscopic treatment presents a significant challenge. The objective of this paper is to introduce a technique for reattaching (in acute injuries) or reinforcing (in chronic injuries) various volar wrist ligaments to the bone, using standard wrist arthroscopic dorsal and volar portals. Methods: There are three common steps for all the arthroscopic volar capsuloligamentous reattachments or reinforcements Step 1 - Volar Portal Establishment: volar radial, volar ulnar and volar central portals are used depending on which structure needs to be reattached or reinforced. Step 2 - Anchor Placement: the anchor is positioned at the site where the ligament has been detached. Step 3 - Capsuloligamentous Suture and Knotting: a knot pusher is introduced inside the joint from the dorsal portal and advanced inside the volar portal where the threads of the anchor are located. The knot pusher is loaded with the threads and retrieved to the dorsal portal. A 16G Abbocath, loaded with a loop is used to pierce the volar ligaments. The loop of the Abbocath is captured from the dorsal portal and loaded with the threads. Both threads are taken to the volar portal and knotted after releasing the traction. This way the knot is placed out of the wrist and the ligaments are reattached or reinforced to the bone. Result: This technique has been used to reinforce and reattach the scapholunate and lunotriquetral ligaments and to reattach the radiocarpal ligaments and the Poirier space. Since this procedure has been performed in various conditions and in conjunction with other ligament treatments (such as perilunate injuries, carpal bone fractures, distal radius fractures, and reinforcement or reattachment of the dorsal portions of intrinsic ligaments), specific results are not presented. Conclusions: The described technique enables the reattachment and reinforcement of most volar ligaments to the bone using standard wrist arthroscopic portals. It can be performed in conjunction with the treatment of the dorsal portion of intrinsic ligaments or other wrist injuries.

Dorsal spanning plate fixation in perilunate injuries: a case report.

A 63-year-old male presented with a trans-scaphoid lunate dislocation after a ten-foot fall. Internal fixation included placement of a dorsal spanning plate (DSP). One-year follow-up yielded a satisfactory outcome. A rigid DSP is a useful tool in acute perilunate injuries to protect internal fixation constructs and help with injury rehabilitation.

An unusual wrist injury in a parkour-athlete: Transstyloid, transscaphoid, transtriquetral perilunate dislocation.

Perilunate dislocations are uncommon high energy injuries. The combination of fractures resulting in a trans-styloid, trans-scaphoid, and trans-triquetral perilunate fracture dislocation is extremely rare. We describe a 20 year old male who suffered this injury after a fall from height while parkouring. He underwent open reduction and internal fixation with ligamentous repair and carpal tunnel decompression. After 3 months, he was noted to have a radiographic evidence of scapholunate dissociation and he returned to the operative room for definitive fixation. Despite this complication, the final functional outcome 6 months after the second surgery was satisfying.

Treatment and Outcomes of Missed Perilunate Dislocations: A Case Series.

Background Perilunate dislocations are devastating injuries that occur relatively rarely, accounting for only 7% of injuries to the carpus. Unfortunately, approximately 25% of these injuries are missed on initial evaluation. Acutely diagnosed perilunate dislocations may be successfully treated with ligament and osseous repair, depending on the injury pattern. Chronic dislocations, however, are primarily treated with salvage procedures. This case series was performed to investigate the outcomes of patients who sustained a perilunate dislocation that was diagnosed in a delayed fashion and look for any treatment patterns that could be more widely applied to future patients. Methods Patients presenting to a single institution between 2016 and 2018 with a perilunate injury that either presented in a delayed fashion or was missed on initial assessment were identified and their characteristics were evaluated. The surgical management of these patients was assessed as was their postoperative course at their 2-week, 6-week, 3-month, and 6-month clinic follow-up visits. Results Eight patients were identified with perilunate dislocations that were diagnosed in a delayed fashion. On average, these dislocations were diagnosed 133 days following the date of injury. All patients were males and 7/8 of them were between 17 and 20 years of age at the time of their injury (mean age: 25.5). They were treated with either primary repair, wrist fusion, proximal row carpectomy, or scaphoid excision and four-corner fusion (SEFCF). Both pain and range of motion improved following surgical management of these injuries. Conclusion Perilunate dislocations are rare injuries that are notorious for being diagnosed late, at which point primary repair is oftentimes no longer feasible. Salvage procedures are able to improve the range of motion and pain of patients who are found to have chronic dislocations. Our case series highlights the importance of treating each missed perilunate injury individually and avoiding a "one-size-fits-all" approach.

Predicting Acute Median Neuropathy in Perilunate Injuries.

Purpose: Perilunate fracture dislocation (PLFD) injuries are associated with the development of acute carpal tunnel syndrome (CTS). The purpose of our study was to identify the factors that increase the likelihood of developing CTS in patients with PLFD. Additionally, we attempted to classify patients who did not initially undergo carpal tunnel release (CTR) at the time of injury but eventually underwent CTR within the follow-up period. Methods: Patients presenting to a level-1 trauma center with isolated PLFDs (Mayfield III-IV) were retrospectively identified by using CPT and ICD-10 codes. Polytraumatized patients, those with a history of previous wrist trauma, or those with previous carpal tunnel symptoms or surgery were excluded. Outcomes of interest included the development of acute CTS, pre- and post-reduction changes in CTS symptoms, and associated hand and wrist fractures. Chi-square tests, Kruskal-Wallis tests, and multivariate logistic regression were used to examine the predictors of developing CTS after a PLFD. Results: In total, 43 patients were included in the final cohort, with a mean age of 44 years, of which 77% were men. The most common fracture of the carpus included scaphoid fractures (9/43, 21%). The average time from presentation to reduction was 636 minutes. Acute CTS symptoms before reduction were present in 26% of the patients and increased post-reduction to 28%. No difference exists between the time to sedation and the presence of acute carpal tunnel symptoms (P >.05). During initial surgical intervention, 79% underwent CTR (27/34). Of the seven patients who did not initially undergo a CTR, 57% (4/7) required a CTR within the follow-up period. Conclusion: Reduction of PLFDs did not significantly improve the number of patients with acute CTS. More than 50% of the patients who did not undergo a CTR at the initial surgery required a CTR within the follow-up period. Type of study/level of evidence: Prognostic III.

A Comparison of Outcomes in Acute Perilunate Injuries: Systematic Review and Meta-Analysis of Treatment Approaches.

BACKGROUND: Perilunate dislocations (PLD) and fracture-dislocations (PLFD) comprise a spectrum of high-energy wrist injuries. The purpose of this review was to review operative strategies for perilunate injuries based on approach and compare outcomes. METHODS: A systematic review of literature on PLD and fracture-dislocations was carried out according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). PubMed and EMBASE databases were queried for literature. Inclusion criteria included English studies reporting clinical or functional outcomes of acute PLD and PLFD. RESULTS: Twenty-nine full-text articles (604 PLD and PLFD injuries) were included. The most common method of PLD and PLFD fixation is through an open approach with combined volar and dorsal exposure. There were no differences between approaches with regard to total arc range of motion, grip strength, Mayo Wrist Score, or mean scapholunate angle. Similarly, there was no difference between approaches and postoperative radiographic arthritis or complications. Most patients were able to return to their prior level of function and work. The incidence of postoperative complications ranged from 0% to 22.5%. CONCLUSION: Current evidence shows no difference in postoperative total wrist arc range of motion, grip strength (as compared to contralateral), or Mayo Wrist Score with regard to surgical approach. The most common method of PLD and PLFD fixation in the literature is through an open approach with combined volar and dorsal exposure. There is a large difference in reported rates of radiographic arthritis, although this finding does not appear to correlate with postoperative pain or disability. LEVEL OF EVIDENCE: I, Systematic Review.

An anatomic study of the morphologic characteristics of the dorsal capitolunate ligament.

PURPOSE: There is consensus in favor of a description of the dorsal ligaments of the carpus as not including a direct ligament between the lunate and capitate. On the other hand, there is an anatomical formation which, according to the currently accepted description, corresponds to the dorsal midcarpal capsule, itself thickened by the dorsal intercarpal ligament. The question is whether the capsule at this point deserves to be called an individualizable ligament. In our operative experience of the dorsal carpus, we have encountered a stout structure adherent to the lunate and capitate. In this article, we present the anatomic evidence of this structure's existence. METHODS: Seven adult fresh frozen upper extremities were dissected. Three wrists were longitudinally sectioned in line with the middle finger metacarpal. The remaining 4 were dissected dorsally. Two representative samples of the stout structure connecting the lunate to the capitate were sent to pathology for histologic analysis and staining. RESULTS: In all 3 of the longitudinally sectioned wrists, a thick band of tissue could clearly be seen, originating on the lunate, spanning the dorsal interval between the lunate and the capitate, and inserting on the capitate. With this structure intact, dorsal dislocation of the capitate was not possible, but preliminary sectioning of the structure allowed dislocation. In the 4 dorsally dissected wrists, the same connection was observed, palmar to the dorsal intercarpal ligament, in every specimen. The average dimensions of the dorsal capitolunate were: 15.25 ± 1 mm long, 8.75 ± 1 mm wide at the midpoint, and 1.75 ± 1 mm thick. The two specimens sent to pathology after sectioning showed longitudinally oriented collagen fibers. This structure also stained positive for elastin and contained intrasubstance vascular structures. CONCLUSION: There is a stout ligamentous structure connecting the lunate to the capitate, palmar to the dorsal intercarpal ligament. Disruption of this structure appears to be necessary for dorsal dislocation of the capitate. Clinical studies are needed to gain better understanding of the exact function and importance of this structure.

Dorsal lunate dislocation and en bloc proximal row carpectomy: a case report.

An unhelmeted 59-year-old male involved in a motorcycle accident presented with a right dorsal lunate dislocation in the context of a polytrauma evaluation. Soft-tissue attachments were minimal across the carpus, which allowed for an en bloc proximal row carpectomy. Two-year follow-up yielded a satisfactory outcome given the high energy injury mechanism. Proximal row carpectomy is a useful tool which preserves wrist range of motion in the acute trauma setting and is durable, as demonstrated by our patient's postoperative mobilization using a wheelchair.