Fracture Line Distributions of Undisplaced Distal Radius Fractures in Relation to Rupture of the Extensor Pollicis Longus Tendon.

Rupture of the extensor pollicis longus (EPL) tendon is a known complication after undisplaced distal radius fracture (DRF). However, no report has revealed the relationship between EPL tendon rupture and the fracture pattern. Thus, this study aimed to investigate the characteristics of fractures at risk of EPL tendon rupture using fracture line mapping of undisplaced DRFs. This study used computed tomography imaging data of undisplaced DRFs with (n=18) and without EPL tendon rupture (n=52). Fracture lines obtained from 3D reconstruction data were drawn manually after matching with a 2D template wrist model. Fracture maps represented the fracture line distribution by superimposing the fracture lines of all 70 patients. Heat maps showed the relative frequency of the fracture lines as a gradual color change. Fracture lines of cases with EPL tendon rupture were concentrated in the proximal border of Lister's tubercle. By contrast, fracture lines of cases without EPL tendon rupture were relatively dispersed.

Bone mineral density, limb muscle mass, muscle strength, and exercise capacity are reduced in female patients with distal radius fractures when the unaffected side grip strength is less than 18 kg.

BACKGROUND: Prevention of domino effects after distal radius fractures is important for improving life expectancy. Fragility fractures secondary to falls are associated with decreased bone mineral density, muscle strength, and exercise capacity. Grip strength is one of the simplest and most useful tests to comprehensively judge muscle strength. The purpose of this study was to examine whether grip strength is associated with bone mineral density, limb muscle mass, muscle strength, and exercise capacity, by comparing patient backgrounds based on the presence or absence of grip weakness in female patients with distal radius fractures. METHODS: This study included women with distal radius fractures who visited our orthopedics outpatient department between April 2015 and April 2020. Bone mineral density, limb muscle mass, skeletal muscle mass index, muscle strength (grip strength on unaffected side and quadriceps muscle strength), the Timed Up and Go test, and the Two-Step test were evaluated six to eight weeks after injury. Patients were divided into two groups according to the cutoff value of grip strength (18-21 kg), and 90 age-adjusted and matched participants were compared and examined. RESULTS: At the cutoff value of 18 kg, a significant decrease in lumbar spine and total proximal femur bone mineral density (p < 0.05, p < 0.05), limb muscle mass and skeletal muscle mass index (p < 0.01, p < 0.05), quadriceps femoris muscle strength (p < 0.01), the Timed Up and Go test (p < 0.05), and the Two-Step test (p < 0.01), was observed in the grip-weakness group compared to that in the no-grip-weakness group. CONCLUSIONS: In women with distal radius fracture and grip strength <18 kg on the unaffected side, bone mineral density, limb muscle mass, quadriceps femoris strength, and exercise capacity may be reduced. These results suggest reduced grip strength may be an indicator for further testing to prevent domino effects.

Volar Lunate Facet Rim Fractures: K-I Classification and Technique.

Background and Purpose It is difficult to capture and safely support a small volar lunate facet (VLF) fragment and obtain sufficient initial fixation. The challenge in treating VLF rim fractures has resulted in various management options. The purpose of this study was to evaluate the clinical and radiological outcomes of a consecutive series of VLF rim fractures of the distal radius treated surgically and to report the Kondo-Imatani (K-I) classification of these fractures, using computed tomography (CT) images and surgical technique, which is termed the Plate buttress and Double tiered subchondral support (PD) technique. Patients and Methods A retrospective review was conducted on 35 patients with VLF rim fractures that included postoperative clinical evaluations, CT images, and radiographs. Description of Technique The PD technique to stabilize the VLF fragment with an anatomical and low-profile volar locking plate (VLP). Results All fractures healed at the final follow-up; Mayo wrist performance score average was 81.7 points (45-100), and the quick disabilities of the arm, shoulder, and hand (quick-DASH) score average was 9.5 points (0-31.8), showing relatively good clinical results. Conclusion VLF rim fragments are not amenable to standard VLP fixation. Unstable fixation may result in postoperative correction loss, aseptic necrosis, malunion, radiocarpal subluxation, and wrist dysfunction. This report described the K-I classification for VLF rim fractures of the distal radius and surgical technique, termed the PD technique, to stabilize the VLF rim fragment with an anatomical and low-profile VLP. Level of Evidence This is a Level IV, case series study.

Lateral Ulnar Collateral Ligament of the Elbow Joint: Reconsideration of Anatomy in Terms of Connection with Surrounding Fibrous Structures.

BACKGROUND: To improve the clinical results of lateral ulnar collateral ligament (LUCL) reconstruction of the elbow joint, better understanding of the anatomy of the aponeuroses and joint capsule could be relevant. This study considers the previously described anatomy of the LUCL in relation to the related aponeuroses and joint capsule rather than as a discrete ligament. We hypothesized that the deep aponeuroses of the superficial extensor muscles and supinator form a relevant portion of the joint capsule previously defined as the LUCL. METHODS: Twenty-four elbows (12 right) from 21 embalmed cadavers (age at the time of death, 54 to 99 years) were included in the study. Twenty elbows were studied macroscopically and 4, histologically. The joint capsule was detached from the bones, and local thickness was quantitatively analyzed using micro-computed tomography (micro-CT). RESULTS: The supinator aponeurosis and joint capsule intermingled to form a thick membrane (mean and standard deviation, 4.8 ± 1.2 mm), which we termed "the capsulo-aponeurotic membrane." It was thicker than the anterior (1.3 ± 0.4 mm) and posterior (2.5 ± 0.9 mm) parts of the capsule of the humeroradial joint (p < 0.001). The capsulo-aponeurotic membrane had a wide attachment on the distal part of the extensor digitorum communis and extensor digiti minimi (EDC/EDM) origin of the humerus, the lateral part of the coronoid process, and the posterior part of the radial notch of the ulna. The humeral attachment had a fibrocartilaginous structure. The deep aponeuroses of the EDC and extensor carpi ulnaris (ECU) were connected to the capsulo-aponeurotic membrane. CONCLUSIONS: The capsulo-aponeurotic membrane was composed of the supinator aponeurosis and joint capsule and was attached to the lateral epicondyle of the humerus, radial side of the coronoid process, and posterior part of the radial notch on the ulna. The entire structure appeared identical to the commonly defined lateral collateral ligament. The most posterior part was connected to the EDC and ECU aponeuroses, which is commonly labeled the LUCL but does not exist as a discrete ligament. CLINICAL RELEVANCE: Consideration of the accurate anatomy of the extensive attachment of the capsulo-aponeurotic membrane could provide useful clues for improvement in techniques of LUCL reconstruction and lateral epicondylitis pathology.

Effects of eldecalcitol alone or a bone resorption inhibitor with eldecalcitol on bone mineral density, muscle mass, and exercise capacity for postmenopausal women with distal radius fractures.

BACKGROUND: Distal radius fractures are often the first fractures experienced by adults with osteoporosis, and such fractures provide an opportunity for treatment to prevent a domino effect of future fractures. Most of these fractures result from falls, which may be related to the individual's limb muscle mass, strength, and exercise capacity. Active vitamin D3 positively affects muscle and bone mass. However, the effect of a bone resorption inhibitor is unknown. This study aimed to determine the effects of eldecalcitol alone or a bone resorption inhibitor with eldecalcitol on bone mass, limb muscle mass, and exercise capacity of osteoporotic patients with distal radius fractures and to identify the preventive effects against future fractures. METHODS: Participants were postmenopausal women(n = 99) with distal radius fractures who visited the orthopedics outpatient department in a city general hospital from April 2015 to October 2017. Bone mass, limb muscle mass, skeletal muscle mass index, and muscle strength (grip strength and quadriceps muscle strength), walking speed, 2-step results, and timed up and go tests results were evaluated before and after 1 year of treatment. The instances of fall recurrence and refracture were investigated using a questionnaire. RESULTS: Eighty-five patients completed follow-up assessments for 1 year. After treatment, bone mass and bone mineral density were significantly improved in the lumbar spine and total proximal femur compared to before treatment. Furthermore, skeletal muscle mass index, grip strength on the unaffected side, quadriceps muscle strength, walking speed and 2-step test results after 1 year of treatment were significantly improved. Nineteen and 4 patients experienced fall recurrence and refracture, respectively. CONCLUSIONS: Eldecalcitol alone or a bone resorption inhibitor with eldecalcitol improved bone mass and bone mineral density, and maintained skeletal muscle mass index, muscle strength, and exercise capacity of osteoporotic patients with distal radius fractures.

Efficacy and safety of novel collagen conduits filled with collagen filaments to treat patients with peripheral nerve injury: A multicenter, controlled, open-label clinical trial.

INTRODUCTION: The safety and efficacy of using artificial collagen nerve conduits filled with collagen filaments to treat nerve defects has not been fully studied in humans. We conducted a multicenter, controlled, open-label study to compare the safety and efficacy of artificial nerve conduit grafts with those of autologous nerve grafts. METHODS: We included patients with a sensory nerve defect of ≤30 mm, at the level of the wrist or a more distal location, with the first-line surgical methods selected according to a patient's preference. We compared sensory recovery using static two-point discrimination and adverse events between the artificial collagen nerve conduit and autologous nerve grafting. RESULTS: The artificial nerve conduit group included 49 patients, with a mean age of 42 years and nerve defect of 12.6 mm. The autologous nerve graft group included 7 patients, with historical data of an additional 31 patients, with a mean age of 36 years and nerve defect of 18.7 mm. The rate of recovery of sensory function at 12 months was 75% (36/49) for the artificial nerve conduit group and 73.7% (28/38) in the autologous nerve group. No serious adverse events directly associated with use of the artificial nerve conduit were identified. CONCLUSIONS: The treatment of nerve defects ≤30 mm using artificial collagen nerve conduits was not inferior to treatment using autologous nerve grafts. Based on our data, the new artificial collagen nerve conduit can provide an alternative to autologous nerve for the treatment of peripheral nerve defects.

Volar Distal Radius Anatomy Applied to the Treatment of Distal Radius Fracture.

Volar locking plate (VLP) fixation has become the standard surgical treatment for distal radius fractures. However, flexor tendon rupture is one of the major complications following volar plating. This detailed review on the anatomy and morphology of the volar distal radius might facilitate appropriate placement of the volar plate and thereby avoid flexor tendon rupture. We introduce safe and secure VLP fixation along standard surgical procedures to avoid complications based on anatomy of the volar surface of the distal radius.

Treatment of Intra-articular Distal Radius Fractures.

This review of current literature discusses the morphology of the volar aspect of the distal radius; the surgical procedure, arthroscopic findings, and clinical results of a plate presetting and arthroscopic reduction technique for acute intra-articular fractures; and a novel simulation guidance system for malunited intra-articular fractures. Classification of intra-articular distal radius fractures is also discussed, focusing on central depression fracture fragments, associated soft tissue injuries, and results for measuring scapholunate distances at different sites. Problems of the distal radioulnar joint are reviewed, in particular, functional outcomes of the authors' prospective cohort study on unstable intra-articular fractures involving the distal radioulnar joint.

Joint capsule attachment to the coronoid process of the ulna: an anatomic study with implications regarding the type 1 fractures of the coronoid process of the O'Driscoll classification.

BACKGROUND: The attachment of the anterior joint capsule on the ulnar coronoid process is not yet completely understood. The purpose of this study was to clarify the anatomic relationship between the anterior capsule of the elbow joint and the tip of the coronoid process. METHODS: Seventeen embalmed elbows were used for this anatomic study. The anterior capsule of the elbow joint was reflected, and the attachment of the capsule on the coronoid process was exposed. The attachment of the joint capsule on the coronoid process was macroscopically and histologically observed, its relationship to the coronoid tip was assessed, and the length of the attachment of the joint capsule was measured. RESULTS: The length of the capsule attachment at the radial side of the coronoid (11.9 mm) was greater than that at the ulnar side (6.1 mm). The bone thickness on the coronoid tip from the proximal edge of the joint capsule attachment was 1.9 mm; together, the cartilage and bone thickness was 4.7 mm. At the radial side of the coronoid, the thickness of the joint capsule at the proximal aspect of the attachment of 2 samples was 0.6 mm and 0.3 mm, and that at the tip of the coronoid was 2.6 mm and 1.7 mm, respectively. CONCLUSIONS: The anterior capsule of the elbow joint had a substantial attachment on the radial side of the coronoid process. The subtype 2 tip fractures of the O'Driscoll classification included the joint capsule attachment, joint cartilage, and subchondral bone.

Joint capsule attachment to the extensor carpi radialis brevis origin: an anatomical study with possible implications regarding the etiology of lateral epicondylitis.

PURPOSE: To identify the unique anatomical characteristic of the extensor carpi radialis brevis (ECRB) origin and points of differentiation from other extensors and to clarify the specific relationship of the ECRB to the underlying structures. METHODS: We studied the origin of each extensor macroscopically for its muscular and tendinous parts; to identify the relationship between the ECRB origin and the deeper structures, we also examined the attachment of the joint capsule under the ECRB origin. RESULTS: The ECRB simply originated as a tendon without any muscle, whereas other extensors originated as a mixture of tendon and muscle. At the anterior part of the ECRB origin, the thin attachment of the joint capsule (average width, 3.3 mm) lay deep to the ECRB and was distinct. However, at the posterodistal portion, the joint capsule, annular ligament, and supinator were intermingled and originated as a single wide sheet from the humerus (average width, 10.7 mm). CONCLUSIONS: The anterior part of the ECRB origin was delicate, because the ECRB origin was purely tendinous, and the attachment of the articular capsule was thin compared with that of the posterodistal attachment. This thin attachment could be an initial factor leading to the development of lateral epicondylitis. CLINICAL RELEVANCE: The results of the current study may enhance magnetic resonance imaging understanding and may help clarify the etiology of the lateral epicondylitis.

An anatomical study of the watershed line on the volar, distal aspect of the radius: implications for plate placement and avoidance of tendon ruptures.

PURPOSE: The watershed line is a useful surgical landmark for positioning a volar locking plate. Implants placed on or distal to it can impinge on flexor tendons and cause injury. However, the details of the anatomy of this line are unclear. We studied macroscopically and histologically the structures of the volar aspect of the distal radius. METHODS: We studied 20 distal forearm regions of 10 cadavers (5 males and 5 females; mean age, 79 y [range, 56-88 y]) to clarify the details of the watershed line. In 16 specimens, we investigated the macroscopic appearance of the volar aspect of the radius and the relationships among the bone, the volarradiocarpal ligaments, and the pronator quadratus. Histological analyses were performed in 4 specimens of 2 cadavers to examine the morphology of the margin of the bony structures. RESULTS: In the medial half of the distal volar radius, 2 lines were identified by direct macroscopic visualization; one was the proximal line that corresponded to the distal ridge of the pronator fossa, and the other was the distal line, which was more prominent. A medial bony prominence was situated on the distal line. In the lateral half, the distal and proximal lines of the medial half merged to form a single line. A lateral prominence was situated on this line. CONCLUSIONS: The watershed line might not be a distinct line, and it corresponds to the distal margin of the pronator fossa in the lateral half of the volar radius and to a hypothetical line between the distal and proximal lines in the medial half. The medial and lateral bony prominences on the volar radius should be key structures for accurate plate placement to avoid flexor tendon injury. CLINICAL RELEVANCE: The present study suggests bony landmarks for positioning a volar locking plate.

Biomechanical evaluation of the fixation methods for transcondylar fracture of the humerus:ONI plate versus conventional plates and screws.

We biomechanically evaluated the bone fixation rigidity of an ONI plate (Group I) during fixation of experimentally created transcondylar humerus fractures in cadaveric elbows, which are the most frequently observed humeral fractures in the elderly, and compared it with the rigidity achieved by 3 conventional fixation methods:an LCP reconstruction plate 3.5 using a locking mechanism (Group II), a conventional reconstruction plate 3.5 (CRP) with a cannulated cancellous screw (Group III), and a CRP with 2 cannulated cancellous screws (CS) in a crisscross orientation (Group IV). In the axial loading test, the mean failure loads were:Group I, 98.9+/-32.6;Group II, 108.5+/-27.2;Group III, 50.0+/-7.5;and Group IV, 34.5+/-12.2 (N). Group I fixations failed at a significantly higher load than those of Groups III and IV (p<0.05). In the extension loading test, the mean failure loads were:Group I, 34.0+/-12.4;Group II, 51.0+/-14.8;Group III, 19.3+/-6.0;and Group IV, 14.7+/-3.1 (N). Group IV fixations showed a significantly lower failure load than those of Group I (p<0.05). The fixation rigidities against mechanical loading by the ONI plate and LCP plate were comparable. These results suggested that an ONI system might be superior to the CRP and CS method, and comparable to the LCP method in terms of fixation rigidity for distal humerus fractures.

Custom AO small T plate for transcondylar fractures of the distal humerus in the elderly.

The purpose of this study was to present a new internal fixation technique for transcondylar fractures of the humerus in elderly patients. Seventeen patients, aged older than 70 years, with displaced transcondylar fractures were treated by our new surgical method. All fractures were fixed by a customized AO small T plate and a transcondylar screw passed from the lateral epicondyle to the medial wall of the trochlea across the humeral condyle. The plate was hand-shaped, trimmed, and applied at the lateral side of the fracture site, and either a cannulated cancellous screw or an AO one-third tubular plate was applied at the medial side of the fracture site. All patients in this study had osteoporotic bone and a small distal fragment. They were followed up for a mean of 30 months (range, 24 to 60 months). Radiographically, union was achieved completely in all patients, and all except 1 had maintained the postoperative alignment. Bone graft or cement fixation was not required in any case. The assessment of the results by use of the modified Cassebaum's rating scale was excellent in 3 cases, good in 11, and fair in 3. With the custom AO small T plate and transcondylar screw fixation technique, the screw that passes through the humeral condyle provides good stability even in cases with a small osteoporotic fragment of the distal humerus. The screw does not damage the articular surface of the elbow joint, and stable fixation can be obtained even in osteoporotic bone.