Lisa Reissner

The distal radius intramedullary nail (DRIM-nail) was developed as a minimally invasive alternative to traditional fixation methods for extra-articular distal radius fractures. This study evaluates functional and radiological outcomes following DRIM-nail implantation. A retrospective case series was conducted, including all patients who underwent DRIM-nail fixation between January 2019 and August 2025. Primary outcome measures included radiographic parameters (fracture consolidation, volar tilt, radial inclination, and ulnar variance) and functional assessments (range of motion [ROM], grip strength, and pain levels). Complications and revision surgeries were also analyzed. Twenty-two patients (19 female and 3 male) with a median follow-up of 11.7 months (interquartile range [IQR]: 7.1, 12.5) were analyzed. Radiographic assessment showed fracture consolidation in all cases, with a median volar tilt of 12.3 degrees (IQR: 7.9, 15.3), radial inclination of 24.0 degrees (IQR: 21.3, 25.1), and ulnar variance of + 0.75 mm (IQR: − 0.80, + 1.50). Functional evaluation revealed no significant differences in grip strength or ROM compared with the contralateral side (all p > 0.05). No complications such as tendon irritation or nerve lesions have been observed. Two hardware removals were performed at the explicit request of the patients. The DRIM-nail provides stable fixation for extra-articular distal radius fractures while preserving soft-tissue integrity. Short-term outcomes demonstrate good safety, satisfactory functional outcomes at final follow-up, and minimal complications. These findings suggest that the DRIM-nail may represent a viable alternative to traditional volar plating in selected extra-articular fractures and warrants further investigation in larger cohorts. Level IV (therapeutic; case series).

Forearm rotation depends on the multiplanar bowing of the radius and ulna. Despite the importance of the fundamental 3D anatomic understanding of the forearm for fracture fixation or implant design, all morphological studies have applied only two‐dimensional methods rather than analyzing the true full 3D space. No study investigated the intra‐pair relation of ulna/radius either. Therefore, we processed CT scans of 30 healthy forearms into 3D models. Each bone was divided into 10 segments along the rotation axis, creating 11 cross‐sections with central points. Connecting these central points yielded the Central‐Line. Bowing was quantified as the Bowing‐Index (area under the Central‐Line). Bowing was analyzed in ap, sagittal and the newly defined Main‐Deformity‐Axis (MDA) plane. Maximal radial deviation averaged 6.4 ± 2.3 mm in frontal, 1.3 ± 3.3 mm sagittal, and 7.2 ± 1.8 mm in MDA plane over all forearms. Maximal ulnar deviation was greater with 8.2 ± 2.9 mm frontal, 9.5 ± 1.7 mm sagittal, and 12.3 ± 2.1 mm in MDA. MDA orientation angle (angular tilt in the dorso‐radial direction in the axial plane) was dorso‐radial, with significantly larger out‐of‐plane bowing in the ulna (60.4° vs. 15.0°; p < 0.01), yielding an average intra‐bone‐pair‐difference of 45.5° ± 33.0°. A negative correlation was found between radius and ulna MDA angles ( r = −0.40, p = 0.030). The Bowing Index was higher in the ulna across all planes ( p ≤ 0.011), with a significant negative correlation between Ulna and Radius (MDA plane, r = −0.38, p = 0.036). Distal ulna analysis revealed consistent dorsal and slight ulnar tilt. The Central Line Method enables 3D characterization of forearm bowing, identifying deformity planes beyond frontal/sagittal axes. For the first time, significant negative correlations between radial and ulnar bowing were demonstrated. These insights hold clinical relevance for fracture fixation, osteotomy planning, and implant design.

Climbing with extreme finger positions is a risk factor for osteoarthritic changes. Our initial study revealed a large variation in PIP joint flexion, especially in older climbers. This study compares finger joint motion between age groups and examines relations to degenerative changes. Nine young (~33.9 years) and 11 old (~55.8 years) participants climbed a defined boulder problem in four grip positions: crimp, half-crimp, open-hand and participant-selected grip. Finger and wrist kinematics were recorded by an optical motion capture system, contact forces were measured using four instrumented holds, osteophytes were assessed using ultrasound and maximal finger strength was measured separately. Older climbers demonstrated significantly (p < 0.0001) reduced PIP flexion compared to younger climbers in crimp (65° vs. 85°), half-crimp (53° vs. 75°), and self-selected grip positions (56° vs. 76°), with no difference observed in open-hand grip (33° vs. 37°; p = 0.44), which is biomechanically less demanding on the PIP joints. The self-selected grip corresponded to the half-crimp position. Osteophytes were rare in younger climbers (PIP: 8.33%, DIP: 16.67%) but common in older climbers (PIP: 68.18%, DIP: 81.82%), with a negative correlation with PIP flexion and a positive correlation with DIP flexion without age differences in maximal force (limited to male climbers). The half-crimp position generated higher maximal finger strength than the open-hand grip, and maximal finger strength was applied with a more open hand position. Older climbers apply lower finger forces and demonstrate less extreme finger joint kinematics associated with higher osteophyte prevalence, while preserving maximal finger strength, suggesting adaptive, joint-protective movement patterns.

Eccentric finger movements have been identified as risk factor in the injury mechanism of pulley ruptures during climbing. So far, they have mainly been associated with inadvertent events. Whether eccentric movements also occur as regular motion patterns was not assessed. Main purpose of this study was to examine eccentric finger movements during typical climbing tasks. Therefore, kinematics and interaction force of eleven elite climbers was recorded during a sequence of four climbing moves. Participants were instructed to use crimp, half-crimp, open-hand grip and campusing. Change of flexion angle in the proximal interphalangeal (PIP) joints from the start to the end of the holding phase (ΔPIP_P2) was calculated. Mean ΔPIP_P2 was -1.5° (SD 6.6°), 0.2° (5.1°), -2.9° (3.4°) and -6.0° (9.6°) for the open-hand, half-crimp, crimp and campusing task, respectively, whereby negative values represent eccentric movements. Eccentric finger joint movements (ΔPIP_P2 < 0°) during the holding phase were very common (59-73%) across all grip types. The loading rate was highest during campusing and lowest using the crimp grip. Climbers exhibit eccentric finger movements not only during accidental slips or when fatigued, but also as consistent patterns. Further research is needed to assess whether these differences are associated with an individual's risk of pulley injury.

Introduction: The purpose of the study was to describe thumb kinematics and function during basic motion tasks and activities of daily living following different surgical techniques for trapeziometacarpal (TMC) joint osteoarthritis using a three-dimensional motion capture system. Methods: Included were 24 patients (29 thumbs) following Wilson osteotomy, Touch prosthesis arthroplasty and trapeziectomy with ligament reconstruction and tendon interposition (LRTI) at a minimum of 12 months postoperatively. Results: During basic motion tasks, it was observed that patients after LRTI showed alterations in most of the assessed movements, while osteotomy and Touch patients showed a preserved range of motion. Altered mobility of the TMC joint was more evident in the combined movements of opposition or circumduction compared with standard anatomical planes. In activities of daily living, we found a similar range of motion of the trapeziometacarpal joint in all groups, but different movements in the adjacent joints, including marked hyperextension of the metacarpophalangeal joint in the LRTI group. Conclusion: Our study found different preservation of the maximal ROM following different TMC joint procedures. Information about the higher preserved range of motion following osteotomy and arthroplasty may be additional factors for consideration when choosing a procedure. Three-dimensional assessment of thumb kinematics after various trapeziometacarpal joint surgeries can enhance our understanding of expected outcomes and can also aid in postoperative assessment and patient education. Level of evidence: III

Rotational deformities of the forearm occur due to neurological imbalance of pro/supinating forces, commonly seen in brachial plexus birth injury. Brachioradialis rerouting has been described for the correction of active pronation or supination deficits. Fixed deformities cannot be addressed by soft tissue procedures alone, and need derotational osteotomies. More recently, techniques combining biceps rerouting and forearm osteotomy have been described. We present an alternative technique to correct fixed rotational forearm deformities by derotational forearm osteotomy and brachioradialis tendon rerouting. The technique can be used to correct both supination and pronation deformities, because the brachioradialis tendon can be rerouted to support either of the 2. No tenotomy and no tendon reconstruction has to be performed. This allows for early mobilization and eliminates the risk of complications at the site of tendon reconstruction.

Background: Scaphoid reconstruction after an established non- or malunion is challenging and recent developments have shown the feasibility to reconstruct it with 3D-planned and -printed patient-specific instrumentation. Methods: Our study compared the clinical outcome of computer assisted 3D-reconstructions of the scaphoid using patient-specific guides for primary and revision reconstructions of scaphoid nonunion regarding clinical outcome. Therefore, 39 patients with primary scaphoid nonunion or malunion and 15 patients with nonunion or malunion after a previous operative treatment were treated with patient-specific guides and followed up for a mean of 10.5 months. The consolidation was assessed with a CT-scan, and the time to consolidation was recorded. Pain level, satisfaction, wrist range of motion, and grip strength were measured and compared. Results: The wrist range of motion and grip strength of the two groups were similar, except for the wrist extension, which was significantly reduced in the revision group. Consolidation was observed in 36/39 patients (92%) in the primary group and in 13/15 patients (87%) in the revision group. Our results showed similar clinical results postoperatively between primary reconstructions and revision surgery. Conclusions: The use of 3D-planned and -printed patient-specific instrumentation proves to be similarly effective in revision surgeries for the reconstruction of the scaphoid as it is in primary surgeries.