We retrospectively evaluated a consecutive series of 42 Motec thumb carpometacarpal total joint arthroplasties. The primary endpoint was revision with implant removal and trapeziectomy. At follow-up the disability of the arm shoulder and hand (DASH) score, pain on numerical rating scale at rest and with activity and serum chrome and cobalt concentrations were assessed for both unrevised and revised patients. At a mean followup of 26 months, 17 patients had been revised. The 2 year cumulative revision rate was 42% (95% CI, 28-60%). The DASH score and pain scores at rest and with activity were comparable between the patients whose thumbs remained unrevised and those revised. Patients with elevated serum chrome and cobalt levels had significantly higher DASH and pain scores, but elevated levels were not associated with revision. The revision rate in this study is unacceptably high. However, pain and DASH scores after revision are acceptable and comparable with patients with non-revised implants. Level of evidence: IV

Distal radioulnar joint instability is difficult to grade by clinical examination and interobserver reliability is low. This study used a new and precise radiostereometry method for measurement of distal radioulnar joint translation. Eight human donor arms were positioned in a custom-made fixture and a standardized piano key test was done with pressure on the ulnar head. Examination was done before and after dividing the styloid and foveal insertions of the triangular fibrocartilage complex. In the intact wrists, the piano key test induced a mean 1.36 mm translation of the ulnar head, which increased statistically significantly to 1.96 mm after a lesion of the styloid ligament insertion and to 2.3 mm after combined lesions of the styloid and foveal ligament insertions. This experimental cadaver study demonstrates a radiological method for precise quantification of distal radioulnar joint stability after different grades of triangular fibrocartilage complex injury.

In this prospective study, we aimed to analyse the early results of 200 consecutive total trapeziometacarpal joint arthroplasties using the Moovis cup, a new generation, dual-mobility, uncemented conical cup, with special focus on early complications. At the 24-month follow-up, we found clinically relevant improvement of function and comfort. Among intraoperative complications were nine intraoperative trapezial fractures, which were treated by screw osteosynthesis; prolonged immobilization; and conversion to cemented cup fixation or primary or secondary trapeziectomy. One was left untreated as the loose cup did not cause notable symptoms. There were three implants with polyethylene wear and two with liner dislocation. We conclude that early outcomes of this new-generation implant are favourable, but its surgery is challenging and associated with important intraoperative and early postoperative complications related to the learning curve. Attentive reaming of the trapezium and careful cup impaction are crucial steps to avoid trapezial fracture and early cup failure. Level of evidence: II

Surgical treatment of bony mallet fingers is frequently recommended, but the evidence is sparse. This randomized clinical trial aimed to compare nonoperative splinting versus extension-block pinning of bony mallet fingers with involvement of more than one-third of the joint surface but without primary joint subluxation. Thirty-two patients were randomized and 28 fulfilled the protocol. At 6 months follow-up, there were no significant differences in active extension lag in the distal interphalangeal joint (the primary outcome) or in patient-reported function and pain scores. Flexion and active range of motion in the distal interphalangeal joint and finger-to-palm distance were better in the splinting group, but three patients developed secondary subluxation. We conclude from this study, that splinting these injuries is safe and efficient in restoring joint motion, but splinting does not sufficiently prevent secondary subluxation of the joint. Radiographic follow-up during splinting appears to be necessary. Level of evidence: I

Background Measurement of in vivo distal radioulnar joint (DRUJ) pathomechanics during simple activities can represent the disability experienced by patients and may be useful in diagnostics of DRUJ instability. A first step is to describe the physiological normal limits for DRUJ kinematics in a reproducible and precise test setup, which was the aim of this study. Methods DRUJ kinematics were evaluated in 33 participants with dynamic radiostereometry (RSA) while performing a standardized press test examination. AutoRSA software was used for image analyses. Computed tomography (CT) forearm bone models were generated, and standardized anatomical axes were applied to estimate kinematic outcomes including, DRUJ translation, DRUJ position ratio, and changes in ulnar variance. Repeatability of dynamic RSA press test double examinations was evaluated to estimate the precision and intraclass correlation coefficient (ICC) test–retest agreement. Results The maximum force during the press test was 6.0 kg (95% confidence interval [CI]: 5.1–6.9), which resulted in 4.7 mm (95% CI: 4.2–5.1) DRUJ translation, DRUJ position ratio of 0.40 (95% CI: 0.33–0.44), and increase in ulnar variance of 1.1 mm (95% CI: 1.0–1.2). The mean maximum DRUJ translation leveled off after a 5 kg force application. The DRUJ translation ICC coefficient was 0.93 within a prediction interval of ± 0.53mm. Conclusions This clinical study demonstrates the normal values of DRUJ kinematics and reports excellent agreement and high precision of the press tests examination using an automated noninvasive dynamic RSA imaging method based on patient-specific CT bone models. The next step is the application of the method in patients with arthroscopic verified triangular fibrocartilage complex injuries. Level of Evidence This is a Level IV, case series study.

In a pig bone model mimicking the human trapezium, we assessed the cementless fixation of trapezial cups in cancellous and cortical bone. Thirty-two saddle-shaped pig forefoot bones were prepared for cup fixation. Conical Konos cups (Beznoska, Kladno, Czech Republic) size 9 mm or 10 mm diameter were impacted. Cup migration was evaluated with repeated radiostereometry after intervals of cyclic-load tests. Migration increased for every load-interval up to 750 N and was higher with cancellous bone fixation than with cortical bone fixation. In cancellous bone, 9 mm cups migrated more than 10 mm cups. At the highest load (1050 N), the cumulative implant survival was 88% for 10 mm cups with cortical bone fixation and 13% for 9 mm cups with cancellous bone fixation. We conclude that mechanical fixation of conical Konos cups was better in cortical than in cancellous bone. Our results further suggest that the largest possible cup diameter should be used.

Purpose Symptomatic instability of the distal radioulnar joint (DRUJ) caused by lesion of the Triangular Fibrocartilage Complex (TFCC) can be treated with a number of surgical techniques. Clinical examination of DRUJ translation is subjective and limited by inter-observer variability. The aim of this study was to compare the stabilizing effect on DRUJ translation with two different surgical methods using the Piano-key test and a new precise low-dose, non-invasive radiostereometric imaging method (AutoRSA). Methods In a randomized experimental study we evaluated the DRUJ translation in ten human cadaver arms (8 males, mean age 78 years) after cutting the proximal and distal TFCC insertions, and after open surgical TFCC reinsertion (n = 5) or TFCC reconstruction using a palmaris longus tendon graft ad modum Adams (n = 5). The cadaver arms were mounted in a custom-made fixture for a standardized Piano-key test. Radiostereometric images were recorded and AutoRSA software was used for image analyses. Standardised anatomical axes and coordinate systems of the forearm computer tomography bone models were applied to estimate DRUJ translation after TFCC lesions and after surgical repair. Results The DRUJ translation after cutting the proximal and distal TFCC insertions was 2.48 mm (95% CI 1.61; 3.36). Foveal TFCC reinsertion reduced DRUJ translation by 1.78 mm (95% CI 0.82; 2.74, p = 0.007), while TFCC reconstruction reduced DRUJ translation by 1.01 mm (95% CI -1.58; 3.60, p = 0.17). Conclusion In conclusion, foveal TFCC reinsertion significantly decreased DRUJ translation while the stabilizing effect of Adams TFCC reconstruction was heterogeneous. This supports the clinical recommendation of TFCC reinsertion in patients suffering from symptomatic DRUJ instability due to acute fovea TFCC lesions.

Background and purpose: Foveal triangular fibrocartilage complex (TFCC) lesion may cause distal radioulnar joint (DRUJ) instability. Dynamic radiostereometry (dRSA) has been validated for objective measurement of DRUJ kinematics. We evaluated DRUJ kinematics by dRSA before surgery and 12 months following open foveal reinsertion of the TFCC in comparison with contralateral non-injured DRUJs.Patients and methods: In a prospective cohort study, 21 patients (11 men) of mean age 34 years (22–50) with arthroscopically confirmed foveal TFCC lesion were evaluated preoperatively, and at 6 and 12 months after open foveal TFCC reinsertion with QDASH, PRWE, pain on NRS, and bilateral dRSA imaging during a patient active press test motion cycle, including a force-loaded downstroke and a release phase.Results: Preoperatively, the force-loaded part (> 2.3 kg; 95% CI 1.6–3.0) of the press test motion cycle (from 15% to 75%) revealed a more volar position of the ulnar head in the sigmoid notch (DRUJ position ratio) and increased distance in DRUJs with foveal TFCC lesion compared with the patients’ contralateral non-injured DRUJ (p < 0.05). 6 months postoperatively, the DRUJ position was generally normalized and remained normalized at 12 months. However, the DRUJ distance remained higher on the injured side. 12 months postoperatively, patients reported less pain during activities, with improved QDASH and PRWE scores (p < 0.007).Interpretation: DRUJ kinematics during the press test showed increased DRUJ translation to a more volar position of the ulnar head after foveal TFCC lesion compared with the contralateral non-injured DRUJs. Open foveal TFCC reinsertion had a stabilizing effect on DRUJ kinematics towards normalization, and improved patient-reported outcomes 6 and 12 months after surgery.