Ulnar Styloid Process Research Articles

Toward an Improved Wrist View: Qualitative and Quantitative Investigation of the 20° Axial Lateral Wrist X-Ray

AimIn standard lateral wrist radiographs, the radiocarpal joint is often obscured because of the angulation of the radial styloid process. A modified lateral projection at a 20° angle has been shown to demonstrate the distal radius in profile in postoperative patients without superimposing of the orthopedic hardware used in open reduction and internal fixation procedures over the wrist joint. We assessed whether this 20° axial-lateral view is advantageous in a wider patient group. Materials and MethodsConsenting adults receiving wrist radiographs in a tertiary hospital radiology department for any indication underwent posteroanterior, posteroanterior-oblique, 0° lateral, and 20° lateral views. A musculoskeletal radiologist and a radiology technologist, blinded to clinical data and to which view was 0°/20°, both evaluated 0°/20° images in random order for whether the radiocarpal joint was obscured by radial styloid, radiocarpal articular margins, or ulnar styloid process, and which view was preferred. ResultsIn 124 cases, the radiocarpal joint was shown clearly on more 20° than 0° views (75/124 vs. 23/124, P < .001). Orthopedic hardware obscured joint lines in fewer 20° than 0° views (12/124 vs. 28/124, P < .001). There was a trend to the ulnar styloid process obscuring part of the radiocarpal joint less in 0° view (28/124 vs. 78/124 in 20°; P = .088), primarily in 20° laterals of wrists with positive ulnar variance. The 20° view was preferred by the radiologist in 76% (95/124) and preferred by the technologist in 83% (104/124). ConclusionThe 20° lateral view was superior to the current 0° lateral view in a wide range of patients, with the radiocarpal joint obscured significantly less by hardware or adjacent anatomy, and preferred by both the blinded radiologist and technologist.

Study on the fracture morphology and imaging of distal radioulnar ligament of type C distal radius fracture

Objective To provide reference data for clinical and biomechanical research through drawing the fracture morphology of type C distal radius fracture and the length of distal radioulnar ligament by fracture mapping technology. Methods From January 2018 to December 2018, 59 cases of OTA/AO 23 C type distal radius fractures were treated in our hospital. Thirty wrist joints of 15 volunteers were used as healthy control group. After thin-layer CT scanning of the wrist joint, the three-dimensional reconstruction was performed by importing the Mimics medical software. The fracture line of the distal radius was introduced into the template after standardization, and the shape of the fracture line was obtained after fitting. The length of the distal radioulnar ligament was obtained by measuring the distance between the sigmoid notch and the base and recess of styloid process of ulna. Results On the radiocarpal joint surface, the fracture line was mainly concentrated around the lunate fossa demonstrated as cross; on the volar side, the fracture line was mainly concentrated around the watery flow line; on the dorsal side, the fracture line was concentrated around Lister's tubercle and scattered; in the area of sigmoid notch, the fracture line was concentrated in the middle 1/3 and dorsal 1/3 of sigmoid notch; in the area of styloid process of radius, it was seen that the styloid process of radius was relatively complete, and the fracture line was distributed under the styloid process of radius. There was no significant difference in the length of the four groups of ligaments, i.e. the volar superficial distal radioulnar ligament, the dorsal superficial distal radioulnar ligament, the volar deep distal radioulnar ligament and the dorsal deep distal radioulnar ligament among the subtypes (C1, C2, C3) of type C distal radius fracture (P>0.05); there was no significant difference between the groups and the healthy control group (n=30, P>0.05). When the fracture line was located in the volar 1/3 and dorsal 1/3 of the sigmoid notch, the length of the palmar superficial distal radioulnar ligament, the dorsal superficial distal radioulnar ligament and the dorsal deep distal radioulnar ligament were significantly different from that of the healthy control group (n=30, P<0.05). Conclusion The fracture pattern of type C distal radius can be visualized by fracture mapping technology. On the radiocarpal joint surface, the fracture line is concentrated around the lunate fossa; in the joint area of sigmoid notch, the fracture line is more concentrated in the middle 1/3 and the dorsal 1/3 of sigmoid notch. When the fracture line is distributed in the volar 1/3 and the dorsal 1/3 of sigmoid notch, it may lead to the risk of distal radioulnar ligament injury. Key words: Radius fractures; Biomechanics; Fracture mapping; Distal radioulnar ligament

Avulsion Injuries of the Hand and Wrist.

Injuries of the hand and wrist are frequently encountered in radiology. Avulsions of the hand and wrist are a heterogeneous group of injuries, but they often have a characteristic imaging appearance that relates to the intricate bone and soft-tissue anatomy and the mechanism of injury. The imaging appearance and this intricate form and function dictate treatment of hand and wrist avulsions. This article reviews frequently and infrequently encountered avulsion injuries and describes abnormalities that may mimic the imaging appearance of avulsions. Specifically discussed entities include the Bennett and reverse Bennett fracture, ulnar collateral ligament avulsion, radial and ulnar styloid process avulsion, triquetral avulsion, mallet and jersey finger, central slip avulsion, and acute and chronic volar plate avulsion injuries. Uncommon avulsion injuries are also described and include avulsions of the scapholunate ligament, extensor carpi radialis longus and brevis tendons, trapeziometacarpal ligament, radial collateral ligament, and flexor digitorum profundus tendon. Emphasis is placed on the relevant anatomy and typical imaging findings for each diagnosis, with pertinent clinical history, pathophysiologic evaluation, and treatment discussed briefly. Understanding the anatomy and expected imaging findings can aid the radiologist in recognizing and characterizing these injuries.©RSNA, 2020.

The influence of radial displacement in distal radius fracture on the stability of distal radioulnar joint

Objective To investigate the causes of instability of distal radioulnar joint caused by displacement in distal radius fracture, and to analyze the importance of radial displacement in distal radius fracture to wrist stability. Methods There were 60 patients with distal radius fracture, 22 males and 38 females, aged from 26 to 67 years, with an average age of 41 years. There were 29 cases with ulnar styloid process fracture and 31 cases without ulnar styloid process fracture. According to the degree of displacement, they were divided into three groups: 13 cases with displacement less than 2 mm, 20 cases with displacement more than 2 mm and less than 4 mm, and 27 cases with displacement more than 4 mm. All the patients were treated with open reduction and plate internal fixation of distal radius fracture. The stability of distal radioulnar joint was examined after plate fixation. Fifteen patients with unstable distal radioulnar joint examined by intraoperative physical examination (associated with ulnar styloid process fracture) were divided into two groups. In one group, the styloid process of ulna was fixed with steel wire, while in the other group the styloid process of ulna was not fixed. The effect of radial displacement on ulnar styloid process after distal radius fracture and the effect of ulnar styloid process fracture on the stability of distal radioulnar joint were analyzed. The degree of radial displacement of distal radius fracture and the effect of ulnar styloid process fracture on the stability of distal radioulnar joint were evaluated according to the postoperative follow-up of palmar inclination angle, ulnar deviation angle and wrist function score. Results The injury of TFCC when radial displacement of distal radius fracture was greater than 4 mm was the main cause of instability of distal radioulnar joint and affecting wrist function. There was statistically significant difference in the incidence of distal radioulnar joint instability whether distal radial fractures accompanied by ulnar styloid process fractures or not. There was significant difference between radial displacement greater than 4 mm and ulnar styloid process fracture. Conclusion The radial displacement of distal radius fracture has great influence on the stability of distal radioulnar joint. There are more patients with ulnar styloid process fracture in the instability of distal radioulnar joint. The ulnar styloid process fracture suggests a higher risk of TFCC injury. The good reduction of ulnar styloid process plays an important role in the stability of distal radioulnar joint. Key words: Radius; Fractures,bone; Distal radioulnar joint; Triangular fibrocartilage complex; Ulnar styloid process

Study on development and biomechanics test of plastic rod-hook plate

To develop a new type of internal fixation device which can be used to treat the minor avulsion fracture of the medial malleolus, lateral malleolus, the base of the fifth metatarsal, and the ulnar styloid process, and investigate the reliability and effectiveness of the device through biomechanical test. Eighty human's bone specimens with complete medial malleolus, lateral malleolus, the base of the fifth metatarsal, and the ulnar styloid process were selected and measured the anatomic indexes (the height, width, and thickness of medial malleolus, lateral malleolus, the base of the fifth metatarsal, and the ulnar styloid process). The CT three-dimensional reconstruction data of 200 healthy adults which including medial malleolus, lateral malleolus, the base of the fifth metatarsal, and the ulnar styloid process was also selected and measured the anatomic indexes by Mimics software. The plastic rod-hook plate was designed according to the measured results and prepared. Forty fresh porcine lower limb specimens were randomly divided into groups A and B (20 in each group), and 8 adult lower limb specimens including 4 left and 4 right were also randomly divided into groups A and B (4 in each group). All specimens were prepared for avulsion fracture of medial malleolus. Then, the fractures were fixed with plastic rod-hook plate in group A and wire anchor in group B. The load and axial torsion test of ankle joint were carried out by universal biomechanical testing machine. According to the anatomical characteristics, a plastic rod-hook plate was designed successfully. The biomechanical test results between animal and human specimens were consistent. There was a linear relationship between load and displacement in the ankle distal load test. The displacement when loaded to the maximum load was significantly lower in group A than in group B ( P<0.05). The torsion angle and torque were significantly higher in group A than in group B when the internal fixation failed in the axial torsion test of the ankle joint ( P<0.05), and the torsion angle was significantly smaller in group A than in group B when the torque was 1 N·m ( P<0.05), and the maximum torque was also significantly higher in group A than in group B ( P<0.05). However, there was no significant difference in torsion angle between the two groups in the maximum torque ( P>0.05). The biomechanical properties of plastic rod-hook plate is obviously better than wire anchor, and the fixation of avulsion fracture with plastic rod-hook plate is easy to operate, which is expected to be used in the clinical treatment of minor avulsion fractures such as medial malleolus, lateral malleolus, base of the fifth metatarsal, and ulna styloid process.

Volar locking plate fixation of distal radius fractures: Isokinetic assessment of the influence of an ulnar styloid process fracture on pronation-supination strength

Although distal radius fractures (DRF) are frequent, the management of associated ulnar styloid process (USP) lesions is still controversial. According to recent studies, a fracture of the USP does not appear to affect functional outcomes after treatment of a DRF with plate fixation. We sought to compare the impact of a USP fracture on pronation and supination strength in isometric and isokinetic tests. We included patients with a DRF who underwent volar locking plate fixation. We divided our population into three groups: one group consisted of patients who had a fracture of the USP base, one group composed of patients without USP fracture or with a distal ulnar fracture only, and a control group composed of subjects with normal wrists. Inclusion criteria included an age of 18 to 50 years and a minimum follow-up of 10 months post-surgery. The main exclusion criteria were complex intraarticular fractures and postoperative complications. The assessment was based on clinical examination and recording of forearm rotation strength during pronation and supination in isokinetic and isometric tests. The ratio between the operated and contralateral sides was compared for each patient. Thirty-six participants were included (mean age 31.1±4.5 years). The mean postoperative follow-up was 17.9±6.9 months. Participants with a USP fracture differed from other participants in their peak torque on the isokinetic test at 45°/s for pronation and supination, but not on isokinetic tests at 120°/s or in isometric tests. Isokinetic tests revealed a decrease in pronation-supination strength during sustained effort for patients with associated basal USP fractures. These findings may have clinical implications for management of the USP but need to be specified with further study. Level of evidenceprognostic study level III.

Impact of reference point selection on DXA-based measurement of forearm bone mineral density.

Forearm fractures are clinically important outcomes from the perspective of morbidity, health care costs, and interruption of work. BMD of the forearm, as derived by dual-energy x-ray absorptiometry (DXA), is a better predictor of fracture at the forearm compared with BMD measured at other sites. However, very few studies have evaluated the technical aspects of selecting the ROI for forearm BMD measurement. This study aimed to compare the BMD values measured at the 1/3 radius site using three different reference points: the ulnar styloid process, the radial endplate, and the bifurcation of the ulna and radius. Healthy Chinese patients participating in the control group of an ongoing study at Zhejiang Provincial People's Hospital were recruited for this study. For each patient, a DXA scan (GE Lunar Prodigy) of the forearm was performed and BMD values were separately calculated using each of the three reference points to identify the ROI. Pearson correlation coefficients were calculated to examine the correlation between the BMD measures derived from each reference point. The F test and independent t test were applied for more robust analysis of the differences in the variances and means. Sixty-eight healthy Chinese volunteers agreed to participate in this study. The root mean square standard deviation (RMS-SD) percentages of BMD values measured at the 1/3 radius site were 2.19%, 2.23%, and 2.20% when using the ulnar styloid process, radial endplate, and the bifurcation of the ulna and radius as the reference points, respectively. Pearson's correlation coefficients for all pairwise comparisons among these three groups were greater than 0.99. F tests and independent t tests showed p values ranging from 0.92 to 0.99. However, we observed that among 10% of patients, choosing an ROI at the ulnar styloid process led to an inability to accurately determine the BMD at the ultra-distal radius. Given equal ability to determine BMD at the 1/3 radius accurately, the radial endplate or the bifurcation of the ulna and radius should be preferentially selected as the reference point for routine forearm BMD measurements in order to avoid situations in which the ultra-distal radius BMD cannot be determined.

Designing a 20 mm incision to protect the dorsal branch of the ulnar nerve during arthroscopic repair of triangular fibrocartilage complex injuries: Cadaver study and preliminary clinical results

The ulnar-sided approach for arthroscopic peripheral triangular fibrocartilage complex (TFCC) repair may be associated with injury to the dorsal branch of the ulnar nerve (DBUN). The goal of this study was to develop a small incision to help minimize DBUN injury. Ten cadaveric upper limbs were used to measure the anatomic parameters of the DBUN. Based on these measured anatomical relationships, a 20 mm longitudinal incision with the ulnar styloid process as the midpoint was designed to explore and protect the DBUN. Three additional cadaveric upper limbs were used to test the feasibility of this method. Then this method was applied in 15 patients with TFCC injury (IB type). In 10 cadavers, the DBUN was located volar to the ulnar styloid process. The mean linear distance between the DBUN and the ulnar styloid process was 8.04 mm (range: 7.02–8.82mm) in the transverse-volar direction and 13.78 mm (range: 11.06–16.02mm) in the longitudinal-distal volar direction. In three additional cadavers, the DBUN was successfully explored and retracted with this incision, creating a safer space for passing sutures and tying knots. This modified method was used successfully in 15 patients, and the DBUN was protected during surgery. There were no complications, and most importantly, no injuries to the DBUN at the 6-month follow-up visit. Therefore, we recommend that a 20 mm longitudinal incision with the ulnar styloid process as the midpoint be made prior to passing sutures during the arthroscopic repair of TFCC tears to avoid injuring the various branches of the DBUN.

A cadaveric study for the volar needle approach to the pronator quadratus using the palmaris longus tendon landmark.

Our aim in this work was to determine the safety and accuracy of the volar approach to the pronator quadratus (PQ) through cadaver dissection. Twenty upper limbs from 10 fresh cadavers were investigated. At the level 3 cm proximal to the ulnar styloid process (USP), a needle was inserted just medial to the palmaris longus (PL) tendon. Distances of the median nerve (MN) and ulnar artery (UA) from the needle insertion point (IP) were measured using ultrasonography and cadaver dissection. The PQ was located at a depth of 10.8-19.9 mm from the skin and had a median thickness of 9.1 mm, measured 3 cm proximal to the USP. The median distances of the MN and UA from the IP were 7.6 and 13.4 mm, respectively. A needle insertion for the volar approach to the PQ was safe at 3 cm proximal to the USP, just medial to the PL tendon.

Analysis of influencing factors of wrist dorsal extension angle and function after radius distal fracture surgery

Objective To explore the influencing factors of wrist dorsal extension angle and wrist function recovery after distal radius fractures. Methods From July 2012 to January 2016, 116 patients with distal radius fractures were treated with palmar plate internal fixation. Follow-up included wrist range of motion, X-ray, measurement of imaging parameters, complications, grip strength, pinch strength, PRWE and DASH scores. According to the recovery of dorsal extension angle and Gartland-Werley scoring criteria, patients with dorsal extension angle less than 45° were classified as groupⅠ (functional restricted group), and patients with dorsal extension angle more than 45° were classified as group Ⅱ (functional unrestricted group). Then, the differences of age, injury side, fracture type, imaging parameters, ulnar styloid process fracture and complications between the two groups were compared, and whether these factors were the influencing factors of different dorsal extension angles were judged. The effects of these factors on wrist PRWE and DASH scores were analyzed. Results There were no significant differences in age, injured side, fracture type, imaging parameters and whether there were fractures of ulnar styloid process between the two groups (P>0.05). There were significant differences in wrist flexion angle, ulnar deviation angle, pronation angle and grip strength between the two groups. The parameters of groupⅠwere lower than those of groupⅡ(P<0.05). The survival analysis of influencing factors of wrist dorsal extension recovery showed that the recovery of ulnar inclination and palmar inclination had an effect on wrist dorsal extension by univariate analysis, while age had an effect on wrist dorsal extension by multivariate analysis; age and ulnar variation had an effect on PRWE score by univariate analysis, and gender and ulnar variation had an effect on PRWE score by multivariate analysis; age had an impact on DASH score by univariate analysis, and gender had an impact on DASH score by multivariate analysis. Conclusion Patients' age, ulnar inclination and palmar inclination are important factors affecting wrist dorsal extension, while age, gender and ulnar variation affect PRWE and DASH scores in varying degrees. Key words: Radius fractures; Wrist joint; Dorsal extension; Influencing factors

Non-union of the ulnar styloid process in children is common but long-term morbidity is rare: a population-based study with mean 11 years (9–15) follow-up

Background and purpose — Fracture of the ulnar styloid process (USP) is common in children in connection with distal radius fracture. The long-term morbidity of USP non-union following a childhood distal radius fracture is unclear. We evaluated long-term clinical and radiographic findings of USP non-union.Patients and methods — All 208 children (< 16 years) who had suffered from distal radius fracture with or without a diagnosed concomitant ulnar fracture during 1992–1999 in the study institution were invited to follow-up at mean of 11 years (9–15) after the injury. Radiographs of both wrists of all 139 participants (67%) were taken; 22 patients showed USP non-union and they made up the study population. Distal radioulnar joint (DRUJ) instability, decreased range of motion (ROM), and weakened grip strength as compared with the uninjured side were the main functional outcomes. Elements of the “Disability of Arm, Shoulder and Hand” questionnaire were used for subjective symptoms.Results — The rate of USP non-union following childhood distal forearm fracture was 16% (22/139) and only 9 of the ulnar styloid fractures were visible in the radiographs primarily. At follow-up wrist flexion–extension ROM and ulnar and radial deviation ranges did not differ between the injured and uninjured sides. Grip strengths were similar. 6 patients reported pain during exercise. 7 had ulna minus (mean 2.3 mm) but none showed degenerative radiographic findings.Interpretation — The long-term clinical results of USP non-union following a childhood wrist fracture were good. However, one-third of the patients with USP non-union had ulnar shortening, which may predispose them to degenerative processes later in life.

Palmar arthroscopic approach and intra-articular anatomy of the bovine carpal joints.

To describe the palmar arthroscopic approaches to the bovine carpus and document the visible intra-articular structures in each approach. Ex vivo study. Thirty fresh cadaveric bovine forelimbs. Computed tomography (CT) and gross dissection were performed on 4 carpi. Latex models were produced from 6 carpi to define the gross anatomy and arthroscopic portals to the palmar carpal pouches. Ultrasonography and arthroscopy were performed on 20 carpi to document visualization of the local anatomy. A single palmar pouch was present on both sides of each joint on gross dissection and evaluation of latex models. The relationship between pouches and palmar structures was observed by CT. Small anechoic areas identified on ultrasonography increased after joint distension. Palmar arthroscopy of the antebrachiocarpal joint enabled visualization of the palmar surfaces of radial, intermediate, and ulnar carpal bones; distal radius; ulnar styloid process; palmar radiocarpal ligament; and articulation of accessory and ulnar carpal bones. Palmar arthroscopy of the middle carpal joint enabled inspection of the palmar aspects of ulnar, intermediate, radial, fused second and third and fourth carpal bones, palmar carpometacarpal ligament, and the short lateral collateral ligament. Palmar aspects of the fourth and fifth metacarpal bones were explored through the palmarolateral approach to the middle carpal joint. Instrument portals for each pouch were created under arthroscopic guidance. Palmar arthroscopy of the adult bovine carpus enabled visualization of the clinically relevant palmar intra-articular structures. Palmar carpal arthroscopy should be considered as an adjunct to dorsal approach for the diagnosis and treatment of bovine carpal diseases.

Lag Screw Fixation for Treatment of an Ulnar Styloid Process Fracture with Antebrachiocarpal Joint Luxation in a Cat

AbstractFracture of the ulnar styloid process can result in clinically debilitating antebrachiocarpal instability. Previously described repair methods include Kirschner wire and figure of eight tension band wire and/or intramedullary pinning. This case report describes surgical repair of a short oblique ulnar styloid process fracture in a cat using two cortical screws placed in lag fashion. Recheck evaluation confirmed lameness-free full return to function with anatomical fracture healing.

A morphological and morphometric study of distal end of ulna with its clinical implications

Background and Aim: The distal end of the ulna is of utmost anatomical importance for normal hand functioning. It can get damaged in various injuries such as avulsion of the ulnar styloid process or ulnar styloid triquetral impaction syndrome. Hence, the aim of this study is to measure the various dimensions of distal end of ulna and to look for its various morphological features. Materials and Methods: The study was conducted on fifty dry ulnae of unknown sex. Length ofstyloid process, width of fovea, and pole and height ofseat were measured. Various morphological features of the distal end of ulna were also noted down. Results: The mean length of styloid process, width of fovea, and pole were 0.55, 0.47, and 0.56 cm, respectively. The mean height of seat was 0.72 cm. In 59.57% of cases, the styloid process was straight and in 78.7% of cases, the tip of the styloid process was blunt. The most common shape of pole was kidney shape in 48% of cases. Conclusion: The results of this study will be useful for hand surgeons in dealing with distal ulnar injuries and even for reconstruction of the distal radioulnar joint with prosthesis of distal end of ulna.

Surgical anatomy of the dorsal cutaneous branch of the ulnar nerve and its clinical significance in surgery at the ulnar side of the wrist.

The dorsal cutaneous branch of the ulnar nerve can be easily injured during surgery at the ulnar side of the wrist. We sought to identify the surgical anatomy, the pathway around the ulnar styloid process and the safe zone of the dorsal cutaneous branch of the ulnar nerve. In 44 forearm dissections, we found that the dorsal cutaneous branch of the ulnar nerve originated at a median distance of 6.8 cm proximal to the tip of the ulnar styloid. We classified the crossing pattern of the dorsal cutaneous branch of the ulnar nerve at a vertical axis into three types. The most common type featured the dorsal cutaneous branch of the ulnar nerve crossing the vertical axis at a median distance of 10.0 mm distal to the tip of the ulnar styloid. In 14% of specimens, the dorsal cutaneous branch of the ulnar nerve crossed the vertical axis at the level of the tip of the ulnar styloid. By mapping the course of the nerve using a Cartesian coordinate system, it was found that the areas located proximal and palmar to the tip of the ulnar styloid had a very high density of dorsal cutaneous branches of the ulnar nerve. We were unable to establish a safe zone. We recommend identifying the dorsal cutaneous branch of the ulnar nerve in every patient undergoing surgery at the ulnar side of the wrist.

Cine MRI of the Triangular Fibrocartilage Complex during Radial-Ulnar Deviation.

Purpose Changes in the shape of the triangular fibrocartilage complex (TFCC) during radial-ulnar deviation were studied using "cine-mode" magnetic resonance imaging (MRI) in 10 right wrists of healthy volunteers, 5 wrists of TFCC tear, and 5 wrists of ulnar styloid nonunion. Subjects and Methods The wrist was fixed in a custom acrylic device, which only allows radial and ulnar deviation. Coronal MR images of nine radial-ulnar deviated positions (every 5 degree from 15 degrees radial deviation to 25 degrees ulnar deviation) were obtained in volunteers and patients. Cine-mode MRI was assembled and was output to MPEG video to observe. Results Cine MRI demonstrated the ulnar side of the TFCC was elongated by average 15 mm in 15 degrees of radial deviation and shortened by average 8 mm in 25 degrees of ulnar deviation in all normal TFCC subjects. Distal portion of the triangular fibrocartilage (TFC) was compressed during radial-ulnar deviation in 10 healthy volunteers and in 3 patients, but proximal portion of the TFC was stable throughout the motion. In contrast, the wavy deformities on the disc in ulnar deviation were observed in three patients with horizontal tear inside the TFCC. In nonunion of the ulnar styloid process, the fragment was snapped in maximum ulnar deviated position or elongation of the space between the styloid fragment and ulna was seen. Conclusion This study indicated normal and abnormal changes in the shape of the TFCC during radial-ulnar deviation motion on cine MRI. The abnormal dynamic changes of the TFCC may be seen in ulnar deviated position in patients, which are related to positive ulnocarpal stress test with the wrist forced ulnar deviated.

Morphometric Study of Ulnar Styloid Process and its Clinical Implication

Morphometric Study of Ulnar Styloid Process and its Clinical Implication

Anatomical relationship of palmar carpal bone landmarks used in locating the lunate and capitate during palpation: A cadaveric investigation

Study DesignDescriptive in situ cadaveric study. IntroductionPerforming accurately directed examination and treatment to the wrist requires clinicians to orient to carpal bone structures. Purpose of the StudyTo examine the anatomical relationships that exist within the wrist–hand complex and identify the accuracy of surface anatomy mapping strategies for localizing anatomical landmarks using a palmar approach. MethodsTwenty-three embalmed cadavers were dissected using standardized procedures. Metal markers were placed in the most prominent palmar landmark of key carpal structures. Relationships between the most prominent palpation landmarks and the carpal bones of interest were visualized using fluoroscopy. ResultsThe most successful methods of palmar capitate localization included the midpoint of a line from trapezium tubercle to pisiform; the midpoint of a line from scaphoid tubercle to hamate hook; or the intersection (cross) of these 2 diagonal lines, with successful capitate identification 100% (23/23) of the time. The most successful method for locating the lunate included the midpoint of a line from the radial styloid process to the ulnar styloid process, which identified the lunate in 100% (23/23) of cases. DiscussionThe results of this cadaveric anatomical relationship study support the use of the midpoint of a line from pisiform to trapezium tubercle, the midpoint of a line from scaphoid tubercle to hamate hook, or a combination (cross) of these lines to locate the capitate from a palmar approach. In addition, the anatomical relationships examined in this study support the use of the midpoint of a line from the radial styloid process to ulnar styloid process to locate the lunate from a palmar approach. Knowledge of these anatomical relationships may improve the clinician’s confidence in locating the capitate and lunate during intercarpal examination, special testing, and treatment. ConclusionResults of this study provide information of the anatomical relationships of the carpal bones from a palmar approach, giving clinicians a foundation for proper orientation to the carpal bones during clinical examination and intervention. Further research is needed to evaluate the reliability and accuracy of these methods for surface palpation on live patients.

Combined median and ulnar nerve palsy complicating distal radius fractures.

Fractures of the distal radius only rarely give rise to complications in the immediate postoperative period. Combined median and ulnar nerve palsy is a complication that can be missed by the surgeon. Three cases diagnosed early after surgery are reported here. The patients were 15, 16, and 30 years of age, respectively. None had preoperative neurological deficits. The youngest patient was injured during sports and the other 2 patients during traffic accidents. All 3 patients had a displaced fracture of the distal radius combined with a fracture of the distal fourth of the ulna or ulnar styloid process and were treated by anterior plate fixation. Operative times were 47, 62, and 120minutes, respectively. Compartment syndrome was ruled out based on low pain intensity and absence of forearm tightness to palpation. The electrophysiological study performed 1 month post-injury in all 3 patients showed severe impairments of both median and ulnar nerve function. Median and ulnar nerve release surgery was performed in the 15-year-old 6 weeks post-injury. No nerve damage or fibrosis was seen during the procedure. All patients recovered fully within 3 months and had normal findings from follow-up electrophysiology testing after 6 months. Combined median and ulnar nerve palsy has rarely been reported and is among the rare complications of distal radial fractures that can develop in the event of a high-energy trauma and/or major displacement. Both previously published data and our experience indicate that surgical nerve release is unnecessary. Clinical recovery within 3 months is the rule. IV, case-reports.

Optimal Placement of Needle Electromyography in Extensor Indicis: A Cadaveric Study.

Objective To identify the center of extensor indicis (EI) muscle through cadaver dissection and compare the accuracy of different techniques for needle electromyography (EMG) electrode insertion.MethodsEighteen upper limbs of 10 adult cadavers were dissected. The center of trigonal EI muscle was defined as the point where the three medians of the triangle intersect. Three different needle electrode insertion techniques were introduced: M1, 2.5 cm above the lower border of ulnar styloid process (USP), lateral aspect of the ulna; M2, 2 finger breadths (FB) proximal to USP, lateral aspect of the ulna; and M3, distal fourth of the forearm, lateral aspect of the ulna. The distance from USP to the center (X) parallel to the line between radial head to USP, and from medial border of ulna to the center (Y) were measured. The distances between 3 different points (M1– M3) and the center were measured (marked as D1, D2, and D3, respectively).ResultsThe median value of X was 48.3 mm and that of Y was 7.2 mm. The median values of D1, D2 and D3 were 23.3 mm, 13.3 mm and 9.0 mm, respectively.ConclusionThe center of EI muscle is located approximately 4.8 cm proximal to USP level and 7.2 mm lateral to the medial border of the ulna. Among the three methods, the technique placing the needle electrode at distal fourth of the forearm and lateral to the radial side of the ulna bone (M3) is the most accurate and closest to the center of the EI muscle.