Distal Ulnar Head Research Articles

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.

3D analysis of the distal ulna with regard to the design of a new ulnar head prosthesis

Study designA retrospective, single center, data analysis.ObjectivePersistent pain and instability are common complications after distal ulnar head arthroplasty. One main reason may be the insufficient representation of the anatomical structures with the prosthesis. Some anatomical structures are neglected such as the ulnar head offset and the ulnar torsion which consequently influences the wrist biomechanics.MethodsCT scans of the ulnae of forty healthy and asymptomatic patients were analyzed in a three-dimensional surface calculation program. In the best fit principle, cylinders were fitted into the medullary canal of the distal ulna and the ulnar head to determine their size. The distance between the central axes of the two cylinders was measured, which corresponds to the ulnar offset, and also their rotational orientation was measured, which corresponds to the ulnar torsion.ResultsThe mean medullary canal diameter was 5.8 mm (±0.8), and the ulnar head diameter was 15.8 mm (±1.5). The distance between the two cylinder axes was 3.89 mm (±0.78). The orientation of this offset was at an average of 8.63° (±15.28) of supination, reaching from 23° pronation to 32° supination.ConclusionWith these findings, a novel ulnar head prosthesis should have different available stem and head sizes but also have an existing but variable offset between these two elements. A preoperative three-dimensional analysis is due to the high variation of offset orientation highly recommended. These findings might help to better represent the patients natural wrist anatomy in the case of an ulnar head arthroplasty.Level of EvidenceIII.

Application of force-monitor ultrasonography to assess distal radioulnar joint instability in patients with triangular fibrocartilage complex injury.

In this study, we evaluated the differences and measurement accuracy in the force-displacement relationship of the distal radioulnar joint (DRUJ) between patients with triangular fibrocartilage complex (TFCC) injury and healthy controls using force-monitor ultrasonography. This study included 11 TFCC injury patients and 22 healthy controls. We evaluated differences in the force-displacement relationship of the DRUJ in these patients using force-monitor ultrasonography. Cyclic compression was applied to the dorsal surface of the ulnar head. Distance between the dorsal surface of the distal radius and ulnar head at the DRUJ level was measured in the initial and pressed-down positions. Changes in radioulnar displacement, applied force, and displacement-to-force ratio were measured. Furthermore, we compared the parameters between the affected and unaffected wrists and between TFCC injury patients and controls. The radioulnar displacement and displacement-to-force ratio were significantly larger in the affected wrists than in the unaffected wrists (P = 0.003 and P = 0.02). The affected/unaffected side ratio of radioulnar displacement and displacement-to-force ratio were significantly larger in the TFCC injury patients than in the controls (P = 0.003 and P = 0.02). The area under the curve was 0.82 for the affected/unaffected ratio of the radioulnar displacement. The optimal cutoff value indicated by the receiver-operating characteristic curve for the affected/unaffected ratio of the radioulnar displacement was 1.71; the sensitivity and specificity were 82% and 86%, respectively. Assessing the DRUJ instability with force-monitor ultrasonography may help identify TFCC-injured wrists.

Treatment Modality of Distal Ulnar Head and Neck Fractures Associated With Operatively Treated Distal Radius Fractures Does Not Affect Outcomes.

Background: This study compares the functional outcomes and complications between operatively and nonoperatively treated distal ulnar head and neck fractures associated with internal fixation of concomitant distal radius fractures. Methods: A 7-year retrospective chart review was performed to identify patients with operatively treated distal radius fractures associated with distal ulnar head and neck fractures. Ulnar styloid fractures were excluded. Fifty-eight patients who had a minimum of 6 months of follow-up were identified. Patients were divided into 3 treatment groups: nonoperative, open reduction internal fixation (ORIF), and distal ulna resection. Reviewed data included demographics, injury and treatment details, complications, and patient-reported outcome measures. Outcomes measures included Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity and Patient-Rated Wrist Evaluation (PRWE) surveys. Due to inadequate power, 5 patients treated with distal ulna resection were excluded from statistical analysis. Results: The average patient age was 56 years, with an average follow-up of 27 months. All patients underwent ORIF of the distal radius fracture. Distal ulna fractures were treated nonoperatively in 25 patients, with ORIF in 28 patients, and with distal ulna resection in 5 patients. There were no statistically significant differences in wrist or forearm range of motion, complication rates, secondary procedure rates, PRWE scores, or PROMIS scores between ORIF and nonoperative treatment. Conclusion: No differences in wrist or forearm range of motion, complication rates, secondary procedure rates, PRWE scores, or PROMIS scores were observed between ORIF and nonoperative treatment of distal ulnar head and neck fractures associated with operatively treated distal radius fractures.

Treatment Outcomes in Patients Undergoing Surgical Treatment for Arthritis of the Distal Radioulnar Joint.

Objective Surgical treatment options for distal radioulnar joint (DRUJ) arthritis include distal ulnar resection (DUR), DRUJ arthrodesis, and ulnar head replacement. Ulnar convergence leading to persistent pain and clicking is a relatively common complication of complete DUR and DRUJ arthrodesis with distal ulnar segment resection (DRUJA). This led to the development of the distal ulna hemiresection (DUHR) and distal ulnar stump stabilization techniques to reduce the risk of this complication. Patients may experience incomplete relief of pain and limited range of motion (ROM) with these procedures. We hypothesized that there would be no differences in outcomes between the treatment groups, but patients undergoing DUHR, tendon interposition, or distal ulnar stump stabilization would be at lower risk of complications. Methods Records were retrospectively reviewed for 121 patients undergoing DRUJ procedures between 2000 and 2018 at a single institution to collect patient demographics, surgical details, preoperative diagnosis, and outcomes including complications, revision procedures, ROM, pain, and swelling. Patients were grouped for analysis by procedure type: DUR (Darrach procedure), DUHR (Bowers procedure), and DRUJA (Sauve-Kapandji procedure). Continuous variables were compared using an analysis of variance test and categorical variables using the Freeman-Halton extension of the Fisher's exact test. A multivariate logistic regression analysis was performed to identify significant predictors of outcomes. Results Seventy-three patients underwent a DUR procedure, while 33 patients underwent a DUHR procedure and 11 underwent a DRUJA procedure. Mean follow-up was 70.6 months. Patients undergoing DRUJA were significantly younger than those undergoing DUR or DUHR procedure (42.4 vs. 60.0 vs. 62.1, p < 0.001). No significant differences between groups were demonstrated in measured outcomes. Posttraumatic arthritis was the most common preoperative diagnosis (43.4%). Persistent pain was the most common negative outcome (25.6%) followed by limited ROM (19.7%). Five patients (4.3%) suffered postoperative complications, most common being rupture of extensor tendons. Five patients (4.3%) underwent revision procedures. Body mass index (BMI) was a significant predictor of persistent pain (odds ratio = 1.09, p = 0.031). Conclusion The results of our study suggest that outcomes are equivalent between the three distinct treatment groups. Despite the potential benefits, hemiresection, tendon interposition, and distal stump stabilization had no significant effect on outcomes in this study. More than a quarter (25.6%) of patients undergoing DRUJ procedures experience persistent pain postoperatively, while one-fifth (19.7%) experienced limited ROM. Patients with higher BMI are at a significantly greater risk of experiencing persistent postoperative pain. Level of Evidence This is a Level III, retrospective comparative study.

Evaluation of the modified radio-ulnar line in correlation with imaging features of the distal radio-ulnar joint osteoarthritis, using a 4D CT examination

Purpose: Modified Radio-Ulnar line (mRU) is a previously defined index of the Distal RadioUlnar Joint (DRUJ) and ulnar head alignment. The purpose of our study was to evaluate the association between mRU measurements using Four-Dimensional Computed Tomography (4DCT) examination with clinical symptoms and imaging features of DRUJ osteoarthritis (OA). Methods: In this IRB approved HIPAA compliant study, we scanned 18 wrists (10 patients with unilateral wrist pain and instability). Imaging of the contralateral asymptomatic side was also performed to aid the diagnosis in the symptomatic side. The 4DCT was obtained using a 320-row detector scanner (Aquilion One, Toshiba Medical Systems) in active pronation-supination. Our previous study confirmed the reliability of mRU measurements using 4DCT examination. The mRU measurements were performed in pronation, midpoint and supination by a fellowship trained MSK radiologist. Presence of symptoms (yes vs. no) and the Kellgren-Lawrence grade of OA (0-4) were assessed in correlation with mRU measurements in active motion. Results: The mRU values showed a significantly greater volar motion of the ulnar head in asymptomatic wrists (mRU mean values (P<0.001) in supination. Changes in the mRU measurements from pronation to midpoint (mean change: 0.11 (0.03), P:0.002) and to supination (0.19 (0.03), P<0.001) were significant only in the asymptomatic wrists. Unlike wrists with KL grade >=2, wrists with KL grade <2 had significant changes in the mRU values while moving from pronation to midpoint (mean change: 0.09, P:0.004) and from pronation to supination (0.14, P:0.059). The mRU values in pronation were not associated with the presence of symptoms or DRUJ OA. However, mRU values in supination were significantly correlated with both the presence of symptoms (correlation coefficient: 0.796, P<0.001) and KL grade of DRUJ OA (correlation coefficient: 0.647, P:0.005). Conclusions: while moving from pronation to supination, we observed that presence of clinical symptoms and imaging features of DRUJ OA severity were associated with restricted volar motion of the ulnar head (assessed by the mRU line).

The Use of Distal Ulnar Hounsfield Units to Predict Future Fragility Fracture Risk.

Distal ulnar Hounsfield unit (HU) measurements obtained from computed tomography (CT) scans of the wrist can be used to accurately screen for low bone mineral density. It is unknown whether HU measurements can also predict the risk of future fragility fractures. Therefore, the purpose of this study was to determine if the HU values of the distal ulna correlate to fragility fracture risk. An electronic database of radiographs at a single institution was searched for all wrist CT scans, obtained for any reason, between January 1, 2002, and December 31, 2008, to allow a minimum of 5-year follow-up. Manual measurement of HU on sequential coronal CT slices of the distal ulnar head was taken, and mean values were recorded. Previously determined cutoff values for the diagnosis of low bone mineral density were implemented to stratify patients as at risk or not at risk for future fragility fracture. Medical records were then manually reviewed for the occurrence of any future fragility fracture (hip, spine, proximal humerus, or rib). There were 161 CTs in 157 patients and 34 fragility fractures in 21 patients, with a prevalence of 13.4%. The mean HU in the fragility fracture group was significantly lower(134.2 vs 197.1 HU). The percentage of low HU patients with fragility fractures was significantly higher (22.7% vs 3.8%). The odds ratio for fragility fracture in the low HU group was 7.4 (95% confidence interval, 2.1-26.2). Using previously determined cutoff values, the sensitivity and specificity of distal ulna HU values for identifying patients who would sustain at least 1 future fragility fracture were 85.7% and 55.2%, respectively. Patients with low distal ulnar HU were significantly more likely to sustain a subsequent fragility fracture. A determination of distal ulnar HUs represents a quick, simple tool to identify patients potentially at risk for fragility fractures. Prognostic IV.

Correlation of the Lateral Wrist Radiograph to Ulnar Variance: A Cadaveric Study.

Both positive and negative ulnar variance have been implicated in a variety of wrist disorders. Surgery aims to correct the variance in these pathologic conditions. This necessitates accurate and reproducible measuring tools; however, the most accurate radiographic measurement technique remains unclear. The purposes of this study were to evaluate 3 methods for determining ulnar variance and to compare each with direct anatomic measurement in a cadaver model. We fixed 10 fresh above-elbow cadaver specimens in neutral rotation and obtained standardized fluoroscopic posteroanterior and lateral wrist images. A dorsal approach was performed and two independent investigators directly measured ulnar variance using digital calipers with the cartilage both intact and denuded. Ulnar variance was measured radiographically using the lateral, perpendicular, and central reference point methods. The reliability of each set of measurements (within a 1-mm cutoff) was assessed by the intraclass coefficient; agreement between radiographic and direct measurements was evaluated by the Bland-Altman method. Each method of determining ulnar variance demonstrated near perfect agreement by the intraclass coefficient. The lateral radiograph method correlated highly with the directly measured ulnar variance with the cartilage denuded with an average measurement difference of 0.06 mm. No radiographic measurement technique demonstrated consistent agreement within 1 mm of the measured ulnar variance with the cartilage intact. Ulnar variance measured by the lateral wrist radiograph technique correlates highly with the directly measured osseous ulnar variance. The remaining measurement techniques did not correlate reliably to within 1 mm of the directly measured ulnar variance with 95% confidence. No method was able to account accurately for the articular cartilage thicknesses at the lunate facet of the radius or the distal ulnar head, which we found to vary in an unpredictable manner. Whereas the lateral radiograph has been shown to allow for more reliable standardization of wrist position compared with the posteroanterior view, this study also highlights the inherent limitations of using static radiographic images in evaluating ulnar variance. The results of the current study demonstrate the utility of the lateral wrist radiograph for assessing bony ulnar variance.

Distal Ulnar Hounsfield Units Accurately Predict Bone Mineral Density and Future Fragility Fracture Risk: Level 3 Evidence

There is no financial information to disclose. Hounsfield unit (HU) measurement from wrist computed tomography (CT) may provide an effective screening tool for low bone mineral density (BMD). We hypothesized that HU measurements from wrist CT scans would accurately evaluate forearm BMD, and low HU values would effectively predict the occurrence of fragility fractures. An electronic database of radiographs was queried for all wrist CT scans obtained at a single institution, and a database of all active duty and military dependents was cross-referenced with the CT scan population to identify all patients with both wrist CT and DXA. Hounsfield unit measurements were performed by one author blinded to DXA results on sequential coronal CT slices of the distal ulnar head. Average HU values were compared to forearm and femoral neck T-score determined by DXA scan. Medical records were then manually reviewed for the occurrence of any fragility fracture. There were 161 CTs in 159 patients included; 74 patients also had available DXA scans. For the population with both CT and DXA, average HU were significantly lower in the DXA-confirmed osteoporotic and osteopenic groups when compared to the normal BMD group (98.1 and 126.9HU versus 198.6HU, respectively, P < 0.0001). The upper limit 95% confidence interval for forearm osteopenia patients was 145.8HU. Overall, the prevalence of fragility fractures was 15.7%. Average HU in the fragility fracture group was significantly lower (126.2 versus 200.5HU, P < 0.0001). The percentage of patients with HU below 145.8HU who subsequently sustained fragility fractures was significantly higher (29.5% versus 2.5%, P < 0.0001). The odds ratio for fragility fracture in the low HU group was 16.9 (range: 3.8 to 74.6). The sensitivity of forearm HU for fragility fracture risk was 92.3%, with a negative predictive value of 97.5%. •Patients with low BMD of the forearm and femoral neck had significantly lower HU measurements in the distal ulna on CT when compared to patients with normal BMD, and measurements below 145.8HU were strongly associated with low BMD.•Patients with HU below 145.8HU were 16 times more likely to sustain a subsequent fragility fracture. Using this cutoff, we were able to predict 92% of fragility fractures.•Distal ulnar HU measurements can be performed easily to identify patients with osteoporosis, and to accurately recognize patients at significant risk for fragility fractures.

REMODELING OF DISTAL ULNA AFTER EXCISION ARTHROPLASTY FOR ACUTE COMMINUTED DISTAL ULNAR FRACTURE: A CASE REPORT

Bone adaptation after excision arthroplasty of distal radioulnar joint in an acute traumatic distal ulna fracture has never been reported. A case of irreparable and comminuted distal ulnar head fracture was managed by excising the ulna head and repairing the fovea (deep ligament) attachments of distal radioulnar ligaments, and then an unexpected remodeling of the distal ulna with the shape of pole and seat was noted. The anatomy of deep fibers of distal radioulnar ligament is important not only in biomechanics about the stability of distal radioulnar joint but it is also possible in the morphology about the shape of the distal radioulnar joint.

Biomechanical evaluation of the dynamic radioulnar convergence after ulnar head resection, two soft tissue stabilization methods of the distal ulna and ulnar head prosthesis implantation

The biomechanical performance of the Darrach procedure, its stabilizing methods and the effectiveness of an ulnar head prosthesis was evaluated in this experiment. The purpose of this study was to: (1) analyze the dynamic effects of the resection of the distal ulna on radioulnar convergence; and (2) evaluate the mechanical performance of two soft tissue stabilizing procedures (pronator quadratus advancement flap and ECU/FCU tenodesis) for the unstable distal ulnar stump and the implantation of an ulnar head prosthesis (uHead) following a distal ulnar resection (Darrach procedure) on radioulnar convergence. With a dynamic PC-controlled forearm simulator, cadaveric forearm rotation was actively and passively performed while simultaneously loading the relevant muscles. The resultant total forearm torque and the three-dimensional kinematics of the ulna, radius and third metacarpal were simultaneously recorded in seven fresh-frozen cadaver upper extremities. The resection of the distal ulna created an extreme instability of the forearm with movement of the radius toward the ulna (0.92-0.38 cm compared to the intact state) in each particular loading condition. The implantation of the ulnar head prosthesis effectively restored the stability of the DRUJ by simulating the geometry of the ulnar head. There were significantly better results after the implantation of the prosthesis compared with the Darrach and the soft tissue stabilization procedures. This study provides laboratory validity to the option of implanting an ulnar head endoprosthesis as an attempt to stabilize the distal forearm with instability after Darrach resection in lieu of performing soft tissue stabilization techniques.

Modular Ulnar Head Decoupling Force: Case Report

Cobalt-chrome modular distal ulnar head replacement arthroplasty is a surgical option to restore stability to the distal radioulnar joint rendered unstable by hemi-resection arthroplasty or a total resection arthroplasty. However, the revision of dislocated modular cobalt-chrome ulnar head implants may pose an important intraoperative challenge. The Morse-taper disassembly force of modular ulnar head implants is not available in the current published literature. We present a case in which tremendous difficulty was encountered while revising a dislocated modular cobalt-chrome distal ulnar head implant. The mean Morse-taper disassembly force of the retrieved modular cobalt-chrome implant was 2958 N +/- 1272. At nearly 4.5 times the average body weight, the modular ulnar head Morse-taper disassembly strength presented a formidable force to overcome intraoperatively.

Case report: Revision of failed Sauvé-Kapandji procedure with an ulnar head prosthesis

The Sauvé-Kapandji procedure has been developed in order to solve distal radioulnar joint (DRUJ) disorders. Postoperative results are variable. Complications such as painful ulnar stump, ulnar instability and loss of grip strength have often been described. We report the case of a painful ulnar stump instability resulting from a Sauvé-Kapandji procedure. After several attempted salvage procedures, a custom-made Herbert distal ulnar head prosthesis was implanted. Long-term results showed complete pain relief, improvement of the range of motion and satisfactory grip strength recovery. Our findings confirm that the Herbert custom-made ulnar head prosthesis appear to be a reliable salvage solution for failed Sauvé-Kapandji procedures.

Arthroplasty of the Distal Radioulnar Joint Using a New Ulnar Head Endoprosthesis: Preliminary Report

To report our experience using a distal ulnar head endoprosthesis to treat painful disorders of the distal radioulnar joint (DRUJ) secondary to (1) instability and (2) arthrosis. Our experience with over 2 years of follow-up study consists of 19 wrists (17 patients). All patients presented complaining of pain and functional disability of the upper limb due to convergence instability or arthrosis of the DRUJ. The patients were studied prospectively. Thirteen patients had a total of 37 previous wrist or DRUJ surgical procedures. Standardized preoperative and postoperative assessments included a patient-reported pain score, a functional satisfaction score, forearm range of motion, grip strength as a percentage of that of the opposite limb, and clinical and radiographic examinations. The Mayo Wrist Score was calculated before surgery and at the last follow-up period. Overall, pain scores decreased 50%, and functional satisfaction scores improved 3-fold. Average grip strength improved by 4 kg, or 16% from preoperative measurements. Forearm rotation was unchanged. All wrists were clinically stable on the latest follow-up examination. Two failures occurred early, at 7 and 14 months. Currently, all prostheses remain clinically and radiographically stable. Implant arthroplasty of the distal ulna combined with an adequate soft-tissue repair is recommended to improve pain, function, and strength of the wrist and forearm. Prosthetic replacement of the distal ulna restored stability to the DRUJ in patients with partial or complete excision of the ulnar head or DRUJ arthrosis and corrected radioulnar impingement. Incidences of complications or revision surgery to date have been low. Larger clinical and radiographic assessments will be needed to determine the long-term success of distal ulna prosthetic replacement. Therapeutic IV.

The effect of the wafer procedure on pressure in the distal radioulnar joint

Purpose To investigate the effect of the wafer procedure on pressure within the distal radioulnar joint. Methods The effect of increasing transverse distal ulnar head resection with preservation of the ulnar styloid was evaluated in 4 fresh frozen cadaver arms. Specimens were tested in neutral rotation. A standard transaxial load was applied from the radius to the ulna and the distal radioulnar joint intra-articular pressure was evaluated. Results Increasing amounts of distal ulnar resection led to a linear increase in pressure in the distal radioulnar articulation. Conclusion The wafer procedure leads to an increase in pressure in the distal radioulnar joint that may lead to the early onset of osteoarthritis.

Revision of failed Sauvé Kapandji procedure by distal ulnar head prosthesis

Revision of failed Sauvé Kapandji procedure by distal ulnar head prosthesis

遠位とう尺関節障害に対するＳａｕｖｅ‐ｋａｐａｎｄｊｉ法による治療

Since 1994, we have performed the Sauve-kapandji procedure in 11 the patients for distal ulnocarpal joint disorders. The age at operation ranged from 18 to 54 years (average 41.3 years). Follow up averaged 8.8 months. All cases had ulnocarpal abutment syndrome. The average ulnar variance was +4.9mm and all were corrected with ulnar null variance. Clinical results were evaluated by Fernandez and Inoue's Criteria. Seven cases were evaluated as excellent and four were good. We consider that the best indication of this procedure is for osteoarthritis of the distal radioulnar joint or instability of the distal ulnar head.

Wafer distal ulna resection for triangular fibrocartilage tears and/or ulna impaction syndrome

Partial resection of the distal ulna (wafer resection) has been used to treat patients with symptomatic tears of the triangular fibrocartilage complex or mild ulna impaction syndrome. In this procedure, the distal 2 to 4 mm of the distal ulnar head is resected while preserving the ulnar styloid process and the ligaments attached to it. The triangular fibrocartilage is debrided, repaired, or partially excised as necessary. The procedure is contraindicated if there is more than 4 mm of positive ulnar variance. Thirteen wafer resections of the distal ulna were performed in 12 patients. All had good to excellent results after a minimum follow-up of 1 year. Wafer resection has specific advantages and avoids many of the potential complications of distal ulna recession and ulnar head resection for patients with the conditions described. The procedure is not indicated if instability or degenerative arthritis of the distal radioulnar joint is present or if there is carpal instability.

Distal ulnar head shortening for treatment of triangular fibrocartilage complex tears with ulna positive variance

Patients with a tear of the horizontal part of the triangular fibrocartilage complex and ulna plus variance were treated by excision of the distal part of the ulnar head. Three of the seven consecutive patients also had lunotriquetral ligament injuries and had fusions of that joint. Six of the seven patients had either complete relief or marked improvement of symptoms at the distal radioulnar joint. When ulnar shortening is indicated, ulnar head shortening should be considered.