Outcomes of Ulnar Shortening Osteotomy with an Intramedullary Bone Graft for Idiopathic Ulnar Impaction Syndrome.

Background: Although several techniques for the treatment of ulnar impaction syndrome (UIS) have been introduced, there have still been reports on various complications such as delayed union, nonunion, refracture, wrist pain, plate irritation, and chronic regional pain syndrome. This study aimed to compare the differences in radiological and clinical outcomes of patients in which intramedullary bone grafting was performed in addition to plate stabilization with those without additional bone grafting during ulnar shortening osteotomies (USOs). Methods: Between November 2014 and June 2021, 53 wrists of 50 patients with idiopathic UIS were retrospectively reviewed. Patients were divided into 2 groups according to whether intramedullary bone grafting was performed. Among the 53 wrists, USO with an intramedullary bone graft was performed in 21 wrists and USO without an intramedullary bone graft was performed in 32 wrists. Demographic data and factors potentially associated with bone union time were analyzed. Results: There was no significant difference between the 2 groups when comparing postoperative radioulnar distance, postoperative ulnar variance, amount of ulnar shortening, and postoperative Disabilities of the Arm, Shoulder and Hand score. Compared to the without-intramedullary bone graft group, bone union time of the osteotomy site was significantly shortened, from 8.8 ± 3.0 weeks to 6.7 ± 1.3 weeks in the with-intramedullary bone graft group. Moreover, there were no cases of nonunion or plate-induced symptoms. Both in univariable and multivariable analyses, intramedullary bone grafting was associated with shorter bone union time. Conclusions: USO with an intramedullary bone graft for idiopathic UIS has favorable radiological and clinical outcomes. The advantage of this technique is the significant shortening of bone union time.

Minimial clinically important difference values in distal metaphyseal ulnar shortening for ulnar impaction syndrome and assessment of the relationship between level of the osteotomy and bone union time.

OBJECTIVE: We aimed to define minimal clinically important difference (MCID) values of patient-reported outcome measures (PROMs) for distal metaphyseal ulnar shortening and to assess the relationship between level of the osteotomy and time to bone union. METHODS: 20 patients who had distal metaphyseal ulnar shortening osteotomies due to ulnar impaction syndrome and had at least 6 months of follow-ups were included in this study. The mean follow-up period was 12.3 ± 7.01 months. The PROMs which consisted of patient-rated wrist evaluation (PRWE) and quick disabilities of arm, shoulder, and hand (QDASH) were recorded on the day before the surgery and at follow-up assessments. Grip strength and range of motion were recorded for operated and contralateral wrists at postoperative assessments. Postoperative radiological evaluations of distance of the osteotomy from the distal ulnar articular surface (osteotomy level), the union of osteotomy site; preoperative and postoperative evaluations of styloid-triquetral distance, and ulnar variance were performed using AP wrist x-rays. The MCID values for PRWE and QDASH were calculated using ROC curve analysis. RESULTS: Mean PRWE and QDASH scores decreased statistically significantly. The mean grip strength of contralateral wrists was higher. Mean ulnar variance decreased, whereas styloid-triquetral distance increased postoperatively. Patients with osteotomy levels of greater than 13.7 mm had a longer time from surgery to bone union. Furthermore, patients with time from surgery to bone union shorter than 7 weeks had an osteotomy closer to the ulnar articular surface. The MCID values for PRWE and QDASH were analyzed and calculated through the ROC curve as 22.25 and 20.45, respectively. CONCLUSION: This study has shown us that the osteotomy level affects the time to bone union and an osteotomy closer than 13.7 mm to the ulnar articular surface seems to result in shorter union time. Furthermore, MCID values were defined for PRWE and QDASH as 22.25 and 20.45, respectively. LEVEL OF EVIDENCE: Level IV, Therapeutic Study.

Resection Arthroplasty Is a Valuable Strategy for Humeroradial Synostosis - A Case Report.

A 15-year-old girl with humeroradial synostosis since birth underwent a resection arthroplasty. A trapezoidal resection osteotomy of approximately 2 cm was performed at the anterior part of the bone flexure. This resulted at 18 months in an elbow arc of motion of 60°-110° and forearm pronation/supination of 40° and 60° without postoperative complications and improved disabilities of the arm, shoulder and hand and Hand 20 scores. Radiographic analysis revealed a humeroradial joint with a maintained pseudarthrosis and hinged motion at the humeroulnar joint. When performed by an experienced surgeon, resection arthroplasty corrects humeroradial synostosis, resulting in improvement in range of motion and quality of life. Level of Evidence: Level V (Therapeutic).

Effects of simulated radioulnar synostosis on supination and pronation in cats. A cadaveric study.

OBJECTIVE: To evaluate the effect of an induced synostosis with a screw on pronation and supination in cats. STUDY DESIGN: Ex vivo biomechanical study. SAMPLE POPULATION: A total of 58 feline forelimbs. METHODS: A total of 58 cadaveric feline thoracic limbs were mounted on a custom-built jig with the elbow and carpus flexed at a 90° angle. To exclude any orthopedic disease, radiographs of the forelimbs were performed prior to the mechanical tests. Radioulnar synostosis was imitated with a 2 mm cortical screw through the radius into the ulna in the proximal (Group P; n = 54), middle (Group M; n = 52), and distal (Group D; n = 53) radial diaphysis. The angles of pronation and supination were recorded after manually applying a two-finger tight rotational force to the metacarpus. Rotational tests were performed without a screw (Group N) and with a screw in each of the aforementioned positions. Pairwise comparisons between the groups were performed based on their angles of rotation with a paired t-test with the Benjamini-Hochberg procedure and a mixed model ANOVA. RESULTS: Mean angles of rotation decreased between Group N (129.5 ± 15.9°) and all groups with imitated radioulnar synostosis to a mean angle of 37.5 ± 14.5° (p < .0001). Mean angles of rotation did not differ between the groups with imitated radioulnar synostosis. CONCLUSION: Induced radioulnar synostosis decreases antebrachial rotation by more than two-thirds, regardless of location. CLINICAL SIGNIFICANCE: Implants fixating the radius to the ulna should be avoided in cats, regardless where they are located along the radial diaphysis.

Arthroscopic wafer procedure versus ulnar shortening osteotomy for ulnar impaction syndrome: a systematic review and meta-analysis.

PURPOSE: This study aimed to systematically compare the efficacy and safety of arthroscopic wafer procedure (AWP) versus ulnar shortening osteotomy (USO) for ulnar impaction syndrome (UIS) treatment. METHODS: All the studies included in this meta-analysis compared the efficacy of AWP to USO for UIS and were acquired through a comprehensive search across multiple databases. The meta-analysis was performed by calculating the effect sizes with the Cochrane Collaboration's RevMan 5.4 software. RESULTS: A total of 8 articles were included in this analysis, comprising 148 cases in the AWP group and 163 cases in the USO group. The pooled estimates indicated no significant differences in combined Darrow's Criteria or Modified Mayo Wrist Score, Modified Mayo Wrist Score, DASH scores, grip strength, VAS score, and postoperative ulnar variation. On the other hand, the patients in the AWP group exhibited fewer complications (OR = 0.17, 95%CI 0.05-0.54, P = 0.003) and a lower reoperation rate (OR = 0.12, 95%CI 0.05-0.28, P < 0.00001) than those in the USO group. CONCLUSIONS: The two surgical techniques were both effective in treating UIS but the AWP group showed fewer complications and a lower reoperation rate. Therefore, AWP may present a superior alternative for UIS treatment.

Malignant giant cell tumour of distal ulna.

Giant cell tumour (GCT) accounts for 5% of all primary bone tumours. GCT in the distal third of ulna is quite rare. We present a case of recurrent GCT in distal third of ulna with malignant features involving tenosynovium. The case was treated by wide resection of tumour and on follow up, patient recovered well with no evidence of further recurrence. Considering the features, according to the literature reviewed, is the first case of its type.

At-Risk Median Motor Branch to the Thenar Musculature Crossing Under the Flexor Carpi Radialis in the Forearm: A Case Report.

CASE: A 77-year-old woman who sustained a distal radius and ulna fracture underwent open reduction internal fixation through a standard flexor carpi radialis (FCR) approach. On dissection, a proximal division of the median nerve was identified, with an aberrant motor branch crossing radial to ulnar deep to FCR and superficial to flexor pollicis longus. CONCLUSION: Although many anatomic variants of the median nerve have been described, the current case demonstrates a particularly important median motor branch variant, imposing a substantial risk of iatrogenic injury during a standard FCR approach.

[Clinical characteristics and treatment analysis of three cases of congenital ulnar collateral flexor contracture of the forearm].

Objective: To report the clinical characteristics and treatment analysis of 3 cases of congenital ulnar collateral flexor contracture of the forearm and take a reference for clinic. Methods: A total of 3 patients with congenital ulnar collateral flexor contracture of the forearm were admitted between February 2019 and August 2021. Two patients were male and 1 was female, and their ages were 16, 20, and 16 years, respectively. The disease durations were 8, 20, and 15 years, respectively. They all presented with flexion deformity of the proximal and distal interphalangeal joints of the middle, ring, and little fingers in the neutral or extended wrist position, and the deformity worsened in the extended wrist position. The total action motion (TAM) scores of 3 patients were 1 and the gradings were poor. The Carroll's hand function evaluation scores were 48, 55, and 57, and the grip strength indexes were 72.8, 78.4, and 30.5. Preoperative CT of case 2 showed a bony protrusion of the flexor digitorum profundus tendon at the proximal end of the ulna; and MRI of case 3 showed that the ulnar flexor digitorum profundus presented as a uniform cord. After diagnosis, all patients were treated with operation to release the denatured tendon, and functional exercise was started early after operation. Results: The incisions of 3 patients healed by first intention. Three patients were followed up for 12, 35, and 12 months, respectively. The hand function and the movement range of the joints significantly improved, but the grip strength did not significantly improve. At last follow-up, TAM scores were 3, 4, and 4, respectively, among which 2 cases were excellent and 1 case was good. Carroll's hand function evaluation scores were 95, 90, and 94, and the grip strength indexes were 73.5, 81.3, and 34.2, respectively. Conclusion: Congenital ulnar collateral flexor contracture is a rare clinical disease that should be distinguished from ischemic muscle contracture. The location of the contracture should be identified and appropriate surgical timing should be selected for surgical release. Active postoperative rehabilitation and functional exercise can achieve good hand function.

An alternative treatment for degenerative triangular fibrocartilage complex injuries with distal radioulnar joint instability: first experience with 48 patients.

Treatment of ulnar impaction syndrome combined with distal radioulnar joint instability due to irreparable degenerative triangular fibrocartilage complex injuries can be complex. We describe the outcomes of a novel technique for restoring distal radioulnar stability due to ulnar impaction syndrome using a distally based extensor carpi ulnaris tendon strip combined with ulnar shortening osteotomy in 48 patients. Patients were assessed using standardized outcome measurements. The patient-rated wrist/hand evaluation total score improved from 66 (SD 15) at intake to 40 (SD 25) at 3 months, and 28 (SD 23) at 12 months postoperatively (p < 0.001). Wrist extension and flexion improved significantly at 12 months from 53° (SD 11) to 65° (SD 8) (p < 0.001) and from 45° (SD 10) to 56° (SD 12) (p = 0.01), respectively. Adding a distally based longitudinal extensor carpi ulnaris strip to ulnar shortening osteotomy for restoring distal radioulnar joint stability seems to be an effective treatment in patients with irreparable degenerative triangular fibrocartilage complex injuries due to ulnar impaction syndrome. Level of evidence: IV.

Association between radioulnar impingement and salvage surgical procedures of the distal radioulnar joint: influence of confounding variables.

We conducted an ambispective cohort study to assess the association between symptomatic radioulnar impingement syndrome (SRUIS) and distal radioulnar joint (DRUJ) salvage surgery to examine the influence of confounders on the final effect. The outcome variable was the incidence of SRUIS and the exposure variable was the surgical procedure. Seventy-two patients with median age of 48 years (IQR 25-78) were examined using bivariate and logistic regression multivariate analyses, and confounders were analysed in 15 multivariate models. Overall, SRUIS occurred in 21 patients (29%). Bivariate analysis showed a significant association between SRUIS and type of surgical procedure, observed in 71% after Sauvé-Kapandji, 50% after Bowers and 15% after Darrach procedure. When adjusted for age, aetiology and previous surgery, the significant association disappeared. Confounding is an important factor when accounting for SRUIS after DRUJ salvage surgery. The risk of SRUIS did not depend on the procedure, but rather on patient's age, aetiology and previous surgery.Level of evidence: II.

Physeal Fractures of the Distal Ulna: Incidence and Risk Factors for Premature Growth Arrest.

BACKGROUND: The aim of this study is to assess the rate of distal ulnar growth arrest following physeal fracture and to identify specific risk factors for premature physeal closure. METHODS: A retrospective review of patients with a distal ulnar physeal fracture was performed at a single United States children's hospital. Patients without 6-month follow-up were excluded. Patient demographics, injury characteristics, treatment, and outcomes were abstracted. Fractures were classified by the Salter-Harris (SH) system. All follow-up radiographs were reviewed for changes in ulnar variance or signs of premature physeal arrest. RESULTS: Fifty-six children with distal ulnar physeal fracture at a mean age of 10.7±3.3 years were included with a mean follow-up of 1.9 years. The most common fracture pattern was a SH II (52.7%), versus SH I (29.1%), SH III (9.1%), and SH IV (9.1%). Of displaced fractures (41.1%), the mean translation was 40.2±38.3% the and mean angulation was 24.8±20.9 degrees. Eleven fractures (19.6%) demonstrated radiographic signs of growth disturbance, including 3 patients (5.4%) with growth disturbance but continued longitudinal growth and 8 patients (14.3%) with complete growth arrest. The average ulnar variance was -3.4 mm. Three patients underwent subsequent surgical reconstruction including ulnar lengthening with an external fixator, distal ulna completion epiphysiodesis with distal radius epiphysiodesis, and ulnar corrective osteotomy. Patients with displaced fractures and SH III/IV fractures were more likely to develop a growth disturbance (34.8% vs. 3.2%, P =0.003; 50.0% vs. 11.1%, P =0.012, respectively). Children with less than 2 years of skeletal growth remaining at the time of injury had a higher risk of growth disturbance (46.2% vs. 9.5%, P =0.007). CONCLUSIONS: SH III and IV fractures are more common injury patterns in the distal ulna compared with the distal radius. Growth disturbance or growth arrest occurs in ~20% of distal ulnar physeal fractures. Displaced fractures, intra-articular fractures, fractures requiring open reduction, and older children are at increased risk of distal ulnar growth arrest and should be followed more closely. LEVEL OF EVIDENCE: Level IV--case series.

Reverse Wafer Procedure for Ulnar Impaction Syndrome.

Ulnar impaction syndrome occurs when excessive load across the ulnocarpal joints results in pathologic changes, especially over the articular surface of the ulnar head and proximal ulnar corner of the lunate. The 2 main surgical options in ulnar impaction syndrome are ulnar shortening osteotomy and wafer procedure, whether open or arthroscopically, to decompress the ulnocarpal joint load. However, all of these techniques have their shortcomings and drawbacks. The current study demonstrates a novel technique to decompress the ulnocarpal joint load: the "reverse wafer procedure" for ulnar impaction syndrome. In this surgical technique, we resected the proximal ulnar side of the lunate instead of partial resection of the thin wafer of the distal ulnar head dome in the standard wafer procedure. This technique avoids iatrogenic central tear of triangular fibrocartilage and distal radioulnar joint portal arthroscopy, which is technically demanding while preserving the distal radioulnar joint.

Influence of oblique proximal ulnar osteotomy on humeral intracondylar fissures in 35 spaniel breed dogs.

OBJECTIVE: To investigate the effects of oblique proximal ulnar osteotomy (PUO) on the healing of humeral intracondylar fissure (HIF) in spaniel breed dogs. STUDY DESIGN: Clinical retrospective study. SAMPLE POPULATION: A total of 51 elbows from 35 spaniel dogs. METHODS: An oblique PUO was performed in dogs diagnosed with HIF. The degree of healing of HIF was subjectively and objectively assessed on preoperative and long-term follow-up CT imaging. Objective assessment was performed by measuring the bone density in Hounsfield units (HU) of a rectangular region of interest (ROI) encompassing the entire hypoattenuated humeral fissure. Major and minor complications were recorded. RESULTS: A total of 24 partial and 27 complete HIFs were diagnosed. The follow-up CT scan was performed at a median 18.5 months (range 10-49 months). Subjective assessment confirmed partial or complete healing of the HIF in 41 elbows (80.3%). Objective assessment confirmed a difference in mean HU of the HIF's ROI between preoperative (HU 640) and last follow-up CT images (HU 835) (p = .001). Young dogs (<14 months) had the highest increase in HU of the HIF's ROI. Major complications occurred in five dogs (6 limbs) of which four were related to the lack of healing of the fissure (7.8%). CONCLUSION: Oblique PUO resulted in partial or complete healing of HIF and pain resolution in the majority of dogs. CLINICAL SIGNIFICANCE: This study introduces an innovative approach to achieve healing of the HIF in the dog, which may help reduce the high complication rate traditionally associated with the use of transcondylar screws.

Elbow Ulnar Collateral Ligament Tears in 2023: Evaluation and Management.

The ulnar collateral ligament, also called the medial collateral ligament of the elbow, is the primary stabilizer against valgus loads. This ligament can be traumatically torn, such as in an elbow dislocation, or can tear through attritional damage with overhead sports. Although baseball pitching is the most common contributor, these injuries also occur with volleyball, gymnastics, and javelin throwing. Patients most commonly report a history of medial elbow pain with associated loss of command, control, and throw velocity. The ulnar nerve lies directly superficial to the posterior band of the ulnar collateral ligament and ulnar neuritis is commonly associated with ulnar collateral ligament pathology. Nonsurgical treatment, including rest from activity, flexor-pronator strengthening, and possible platelet-rich plasma injections, can be considered for partial-thickness tears. Surgical treatment can be considered for patients in whom nonsurgical treatment fails and full-thickness tears. Historically, surgical treatment involved reconstruction of the ligament with a tendon graft. Ipsilateral palmaris longus autograft has been the most commonly used graft, but contralateral palmaris, autograft hamstring tendons, and allograft tendon have also been used. This procedure has a high rate of return to play and a low complication rate, but most athletes require 12 to 18 months to fully return. More recently, repair of the ligament, with the addition of a biologic ingrowth ligament augmentation suture, has demonstrated similarly high rates of return to play and low complication rates, with a full return to play in 6 months.

Pediatric parosteal osteosarcoma of the distal radius causing extensive erosive mass effect of the adjacent ulna: a case report.

INTRODUCTION: Parosteal osteosarcomas are low-grade bony malignancies that are treated primarily with surgical resection and reconstruction. This report discusses a unique case of a pediatric patient who presented with a parosteal osteosarcoma of the distal radius causing extensive erosive mass effect and growth disturbance of the adjacent ulna. Likely due to their slow-growing nonaggressive nature, parosteal osteosarcomas have not been previously described to abut adjacent bony structures through direct contact. The patient presented in a significantly delayed manner due to social circumstances, inadvertently revealing this novel behavior. This report reviews this rare case and describes the current understanding of this tumor. CASE PRESENTATION: The patient is a 13-year-old male who presented with a parosteal osteosarcoma of his distal radius. He presented with a palpable wrist mass and wrist stiffness. He presented in a delayed manner with advanced local disease due to social factors. Imaging revealed an osseous radial mass that abutted the ulna and likely stunted its growth. The patient ultimately underwent complex resection and allograft reconstruction of both his distal radius and ulna. Intraoperative pathology was confirmed to have negative tumor margins. Allograft reconstruction of the radius and ulna was performed utilizing patient-specific custom cutting guides. At the 6-month postoperative visit, the patient had no recurrence of the mass, minimal pain, and had almost regained range of motion of the extremities. Clinical radiographs at the 6-month postoperative visit demonstrated allograft incorporation. CONCLUSIONS: A previously unreported case of pediatric parosteal osteosarcoma of the distal radius with erosion of the adjacent ulna through direct contact is presented. The challenges in and the importance of arriving at a definitive diagnosis in a timely manner for the proper treatment of this malignancy are emphasized.

Chronic Volar Distal Radial Ulnar Joint Dislocation: A Case Report with Proposed Treatment Algorithm.

CASE: We report the case of a 34-year-old woman with a chronic right volar dislocation of the distal radioulnar joint (DRUJ) and associated ulnar styloid fracture. The patient presented 1 month after a dog bite injury with wrist pain and limited range of motion, and radiographs demonstrated volar DRUJ dislocation. Closed reduction was unsuccessful, and thus, open reduction was performed. CONCLUSION: Isolated volar DRUJ dislocations in the absence of fractures are easy to misdiagnose on plain radiographs. We present our surgical technique and fixation algorithm for open reduction and stabilization for chronic volar DRUJ dislocations.

Sliding Plate System: A Novel Method and Device for Shortening Osteotomy.

We report a novel sliding plate system (SPS) and its application for radial shortening osteotomy. We conceptualised, designed and introduced the SPS, which helps with precise shortening osteotomy in both radius and ulna. We implanted the SPS in a patient with Kienböck disease following a radius shortening osteotomy. The SPS was safe and efficient, and the surgical technique eliminated extra steps. The SPS affords precise shortening, optimum compression and anatomic alignment after radius shortening osteotomy. Level of Evidence: Level V (Therapeutic).

Vascularized fibular flap and custom-made synthesis in post-traumatic ulnar diaphyseal pseudarthrosis: a case report.

BACKGROUND: Although isolated fractures of the ulnar shaft are considered common and relatively benign injuries, numerous complications can arise especially in the context of suboptimal care pathways. For pediatric patients, however, there is no single indication of the surgical approach. In the context of the management of these complications, it is known that the vascularized fibular graft has numerous advantages and indications in the treatment of recurrent pseudarthrosis. However, in revision surgery the frequent occurrence of anatomical subversions requires the use of fixation means adapted to the individual patient. We present a clinical case of an adult patient suffering from post-traumatic ulnar pseudarthrosis treated with autologous vascularized fibula grafts and 3D-planned custom-made plate. CASE PRESENTATION: A 38-year-old Ivorian woman came to our attention with a painful nonunion of the ulnar shaft and significant dysmorphism of the left forearm, with shortening and flexion of the limb as an outcome of unspecified road trauma in childhood. No alterations of the nerve compartment were reported. As far as detectable, she had undergone autologous bone grafting and implantation of questionable synthetic means, without acute treatment. Since we evaluated the patient (2012), we have performed two debridement surgeries, associated with autologous avascular bone graft from the iliac crest and plate fixation (2012 and 2014). In both cases, rupture of the fixation media was observed. In 2021, the pseudarthrosis was treated with a vascularized fibular bone graft. The subverted radius and ulna anatomy and poor bone quality required patient-specific reconstruction of the pseudarthrosic ulna from a 3D scan and the production of custom-made plate and screws, supported by the creation of special guides for drilling and by optimizing the positioning of screws with preoperative digital models. In the postoperative period, regular follow-up visits with X-rays evaluations were performed at 1, 3 and 6 months after surgery. No inflammatory reactions or local rejection were found. The fibula graft healed at the proximal ulnar junction six months after the operation while it took eight months to heal at the distal junction. Functionally, we observed a pain reduction and a range-of-motion preservation. CONCLUSIONS: The multiple failures of diaphyseal reconstruction with avascular bone grafts have forced the indication to the vascularized fibular flap. This case is a unique experience but we believe that the association between vascularized bone graft and the potential for customization through 3D planning represents a valid surgical potentiality in complex cases of post-traumatic reconstruction.

Morphology of the Radial Attachment of the Radioulnar Ligament and Surrounding Landmarks.

PURPOSE: The triangular fibrocartilage complex (TFCC) is composed of dorsal and palmar radioulnar ligaments (RULs). A common injury pattern of the RUL is the avulsion of the ulnar insertion, which can be treated by arthroscopic or open repair. Although the general method of TFCC reconstruction is a tendon graft with a bone tunnel, detailed information regarding the radial attachment of the RUL is unclear. This study aimed to clarify the morphology of the radial attachments of the palmar radioulnar ligament (PRUL), dorsal radioulnar ligament (DRUL), and short radiolunate ligament (SRL) using three-dimensional imaging. METHODS: A total of 29 upper limbs (16 formalin-fixed and 13 embalmed by Thiel's embalming method) of Japanese cadavers were used. After gross observation, we marked the attachments of the PRUL, DRUL, and SRL using 0.7-mm diameter pins. We created three-dimensional images of the radius, outlining the PRUL, DRUL, and SRL attachments. The software application calculated the centers of the PRUL and DRUL attachments. RESULTS: The PRUL attachment was horizontally shaped. The center of the PRUL was 1.5 mm proximal and 5.8 mm radial to the tip of the palmar pyramid formed by the palmar cortex and the radioulnar and radiocarpal joint surfaces. The DRUL attachment was vertically shaped. The center of the DRUL was 2.0 mm proximal and 1.7 mm radial from the tip of the dorsal pyramid formed by the dorsal cortex and the radioulnar and radiocarpal joint surfaces. The length of the SRL was 9.2 mm. The SRL and PRUL were strongly conjoined. CONCLUSIONS: The anatomical center on the RUL attachment of the radius can be determined from osseous landmarks. CLINICAL RELEVANCE: The findings of this study contribute to the understanding of RUL attachment to the distal radius and may assist surgeons in performing anatomical reconstruction of TFCC.