Normal digital flexion relies on flexor tendon pulleys to transmit linear muscular force to angular digital motion. Despite the critical role these pulleys play, there is a growing trend among surgeons to partially sacrifice or “vent” them during flexor tendon repair to improve surgical exposure. Although this new practice is reported to improve outcomes after flexor tendon repair, there is concern for the long-term effects of bowstringing, reduced finger range of motion (ROM) and altered tendon biomechanics. The objective of this study was to examine the effects of the application of a thermoplastic ring, acting as an “external” pulley, on flexor tendon biomechanics and finger ROM. We hypothesized that the application of an external thermoplastic ring would produce a centripetal force over the tendon to reduce bowstringing, improve finger ROM, and restore tendon loads following pulley venting

Twelve digits comprised of the index, long, and ring fingers from four cadaveric specimens were tested using a novel in-vitro active finger motion simulator. Servo-motors were used to generate motion. Loads induced by flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP), and joint range of motion were measured with each sequential sectioning of the A2, A3, and A4 flexor pulley, in comparison to a native healthy finger condition. At each finger condition, A2 and A4 external thermoplastic pulley rings were applied over the proximal phalanx and middle phalanx, respectively, to recreate A2 and A4 function. Results were recorded and analyzed using a one way repeated-measures ANOVA.

Following venting of the A2, A3 and A4 pulley, proximal interphalangeal joint (PIPJ) ROM significantly decreased by 17.02 ± 8.42 degrees and distal interphalangeal joint (DIPJ) range of motion decreased by 17.25 ± 8.68 degrees compared to intact pulleys. Application of the external rings restored range of motion to within 8.14 ± 8.17 degrees at the PIPJ and to within 7.72 ± 8.95 degrees at the DIPJ. Similarly, pulley venting resulted in a 36% reduction in FDS load and 50% in FDP load compared to intact pulleys. Following application of the external rings, loads were almost restored to normal at 7% reduction for FDS load and 13% reduction for FDP load.

Venting of flexor tendon pulleys significantly alters flexor tendon biomechanics and digit range of motion. The application of thermoplastic rings acting as external pulleys over the proximal and middle phalanges is an effective, inexpensive, non-invasive and reproducible therapeutic method to restore flexor tendon biomechanics and digit range of motion.

To determine the biomechanical effect of increasing scaphoid malunion and scaphoid non-union on carpal kinematics during dynamic wrist motion using an active wrist motion simulator.

Seven cadaveric upper extremities underwent active wrist flexion and extension in a custom motion wrist simulator with scaphoid kinematics being captured with respect to the distal radius. A three-stage protocol of progressive simulated malunion severity was performed (intact, 10° malunion, 20° malunion) with data analyzed from 45° wrist flexion to 45° wrist extension. Scaphoid malunions were modelled by creating successive volar wedge osteotomies and fixating the resultant scaphoid fragments with 0.062 Kirshner wires. At the completion of malunion motion trials, a scaphoid non-union trial was carried out by removing surgical fixation to observe motion differences from the malunion trials. Motion of the scaphoid, lunate, capitate, and trapezium-trapezoid was recorded and analyzed using active optical trackers.

Increasing scaphoid malunion severity did not significantly affect scaphoid or trapezium-trapezoid motion (p>0.05); however, it did significantly alter lunate motion (p<0.001). Increasing malunion severity resulted in progressive lunate extension across wrist motion (Intact – Mal 10: mean dif. = 7.1° ± 1.6, p<0.05; Intact – Mal 20: mean dif. = 10.2° ± 2.0, p<0.05;) although this change was not as great as the difference seen during non-union trials (native – non-union: mean dif. = 13.8° ± 3.7, p<0.05).

In this in-vitro model, increasing scaphoid malunion severity was associated with progressive extension of the lunate in all wrist positions. The clinical significance of this motion change is yet to be elucidated, but this model serves as a basis for understanding the kinematic consequences of scaphoid malunion deformities.

Numerous surgical techniques have been proposed and described in the treatment of Kienbock's disease. The objective of this systematic review was to assess the current evidence and trends in the management of Lichtman Stages IIIA and IIIB.

We performed a literature search using the Medline, Embase, and Cochrane databases to identify studies evaluating treatment outcomes in Stages IIIA and IIIB of Lichtman's Classification. We included studies between 2008 and 2018, and studies with Sackett levels one to four inclusively. We excluded studies that included skeletally immature patients, non-English papers, other hand diseases, and those without evidence of significance testing. We evaluated the quality of each included study using the Structured Effectiveness Quality Evaluation Scale (SEQES) and our outcomes of interest included Pain, ROM, Grip Strength, and Functionality.

We identified 1489 titles from the various databases. 83 papers remained after the subtraction of duplicates and abstract review. Following full-text review of the remaining 83 papers, 43 more studies were excluded and 40 papers met the criteria for SEQES assessment. There were six low-quality papers and 34 moderate-quality papers. Meta-analysis was not possible due to the variability in how outcomes were reported. A variety of surgical options were presented including decompressions, joint-levelling procedures, revascularization techniques, fusions, arthroplasty and novel combinations of these techniques. These were mainly retrospective and/or cohort studies. Most of these papers had small sample sizes and required further studies. Nonetheless, all of these treatment modalities were shown to offer pain relief and some degree of return of function ranging from minimal improvement to return to normal daily functions.

This systematic review has revealed a significant weakness in the literature and a lack of strong evidence in the treatment of Stages IIIA and IIIB of Kienbock's disease. The unknown etiology of this disease and its rarity make it very difficult to produce randomized controlled trials and appropriately-sized studies. As such, there is currently insufficient data to determine a superior treatment modality from another. Furthermore, the fact that most, if not all, surgical interventions produced positive results may also be a consequence of publication bias.

Distal radius fractures are the most common upper extremity injury, and are increasingly being treated surgically with pre-contoured volar-locking plates. These plates are favored for their low-profile template while allowing for rigid anatomic fixation of distal radius fractures. The geometry of the distal radius is extremely complex, and little evidence within the medical literature suggests that current implant designs are anatomically accurate. The main objective of this study is to determine if anatomic alignment of the distal radii corresponds accurately with modern volar-locking plate designs. Additionally, this study will examine sex-linked differences in morphology of the distal radius.

Segmented CT models of ten female cadaver (mean age, 88.7 ± 4.57 years, range, 82 – 97) arms, and ten male cadaver (mean age, 86 ± 3.59 years, range, 81 – 91) arms were created. Micro CT models were obtained for the DePuy Synthes 2.4mm Extra-articular (EA) Volar Distal Radius Plate (4-hole and 5-hole head), and 2.4mm LCP Volar Column (VC) Distal Radius Plate (8-hole and 9-hole head). Plates were placed onto the distal radii models in a 3D visualization software by a fellowship-trained orthopaedic hand surgeon. The percent contact, volar cortical angle (VCA), border and overlap of the watershed line (WSL) were measured.

Both sexes showed an increase in the average VCA measure from medial to lateral columns which was statistically significant. Female VCA ranged from 28 – 36 degrees, and 38 – 45 degrees for males. WSL overlap ranged from 0 – 34.7629% for all specimens without any statistical significance. The average border distance for females was 2.58571 mm, compared to 3.52411 mm for males, with EA plates having a larger border than VC plates. The border distances had statistically significant differences between the plate types, and was approaching significance between sexes. Lastly, a maximum percent contact of 21.966 % was observed in specimen F4 at a 0.3 mm threshold. No statistical significance between plate or sex populations was observed.

This study investigated the incoherency between the volar cortical angle of the distal radius, and the pre-contoured angle of volar locking plates. It was hypothesized that if the VCA measures between plate and bone were unequal then there would be an increase in watershed line overlap, and decrease in percent contact between the surfaces. Our results agreed with literature, indicating that the VCA of bone was larger than that of the EA and VC pre-contoured plates examined in this study.

With distal radius fracture incidences and prevalence on the rise for elderly female patients, it is a necessity that volar locking plates be re-designed to factor in anatomical features of individual patients with a particular focus on sex differences. New designs should focus on providing smaller head sizes that are more accurately tailored to the natural contours of the volar distal radius. It is recommended that future studies incorporate expertise from multiple surgeons to diversify and further understand plate placement strategies.

Scaphoid fractures are a common injury accounting for more than 58% of all carpal bone fractures(1,2). Biomechanical studies have suggested that scaphoid mal-union may lead to altered carpal contact mechanics causing decreased motion, pain and arthritis(1,2). The severity of mal-union required to cause deleterious effects has yet to be established. This limits the ability to define surgical indications or impacts on prevention of posttraumatic arthritis. Computed tomography has been shown to be a useful in determining the 3D implications of altered bony alignment on the joint contact mechanics of surrounding joints. The objective of this study was to report mid-term follow-up image-based outcomes of patients with scaphoid mal-unions to determine the extent to which arthritic changes and decreased joint space is present after a minimum of 4 years following fracture.

Participants (n=14) who had previously presented with a mal-united scaphoid fracture (indicated by a Height:Length Ratio >0.6) between November 2005 and November 2013 were identified and contacted. A short-arm thumb spica case was used to treat X patients and X required surgical management. Baseline and follow-up CT images, were performed with the wrist in radial deviation and positioned such that the long axis of the scaphoid was perpendicular to the axis of the scanner. Three-dimensional inter-bone distance (joint space), a measure of joint congruency and 3D alignment, was quantified from reconstructed CT bone models of the distal radius, scaphoid, lunate, capitate, trapezium and trapezoid from both the baseline and follow-up scans(3). Repeated measures ANOVA was used to detect differences in contact area (mm2) between baseline and follow-up CT's for the radioscaphoid, scaphocapitate and scaphotrapezium-trapezoid joint.

The average age of participants was 43.1 years (16–64 years old). There was significant loss of joint space, indicated by a greater joint contact area 3–4 years post fracture, between baseline and follow-up reconstruction models, at the scaphocapitate (mean difference: 21.5±146mm2, p=0.007) and scaphotrapezoid joints (mean difference: 18.4 ±28.6mm2, 0.042). Significant differences in the measured contact area was not found for the radioscaphoid (0.153) and scaphotrapezium joints (0.72). Additionally, the scaphoid, qualitatively, appears to track in the vorsal direction in the majority of patients following fracture.

Increased joint contact area in the scaphocapitate and scaphotrapezoid joint 3–4 years following fracture results from decreased 3D joint space and overall narrowing. Joint space narrowing, while not significantly different for all joints examined, was reduced for all joints surrounding the scaphoid. Decreased joint space and increased contact area detectable within this short interval might be suggestive of a trajectory for developing arthritis in the longer term, and illustrates the potential value of these measures for early detection. Longer term follow-up and correlation to clinical outcomes are needed to determine the importance of early joint space narrowing, and to identify those most at risk.

Distal radius fractures are the most common upper extremity fracture. The incidence is significantly higher in elderly females with osteoporotic bone. When surgery is indicated, volar locking plates (VLPs) allow for rigid fixation particularly in comminuted fractures with poor bone quality. Although numerous studies have shown the importance of plate placement to avoid soft tissue complications associated with volar plate fixation, there has been little evidence on the anatomic fit of current VLPs. Moreover, the effect of gender differences in distal radius morphology on anatomic fitting of VLPs has not been studied. The aim of this study was to evaluate the gender difference in distal radius morphology and the accuracy of the fit of a current VLP to CT-based distal radius models.

Segmented CT models of ten female (mean age, 89 ± 5 years), and ten male (mean age, 86 ± 4 years) cadaveric wrists were obtained. Micro-CT models of the DePuy-Synthes 4-hole extra-articular (EA) and 8-hole volar column (VC) distal radius VLPs were created. A 3D visualization software was used to simulate appropriate plate placement on to the distal radius models by a fellowship-trained hand surgeon. Volar cortical angles (VCA) of the medial, middle and lateral portion of the distal radius were measured and compared between genders. The accuracy of the fit of the two VLP designs were quantified using the percentage of the watershed line (WSL) overlapped by the plate (WSL overlap), the distance between the WSL and the most distal aspect of the posterior plate (prominence distance) and the percentage of contact between the plate and bone.

There were statistically significant gender differences in medial, middle and lateral VCAs (p=.003 medial, p=.0001 middle, p=.002 lateral). VCA ranged from 28° to 36° in females and from 38° to 45° in males. The WSL overlap did not show statistically significant gender differences (male: 5.9%, female: 13.6%, p=.174). However, the difference in prominence distance between different genders approached statistical significance (male: 3.5mm, female: 2.6mm, p=.087). Contact mapping between the plate and bone did not demonstrate a perfect contact in any of our specimens. Thus, contact measurements were categorized into 0.1mm, 0.2mm, and 0.3mm threshold contacts. There were no statistically significant gender differences in any of the threshold categories (0.1mm: p=.84, 0.2mm: p=.97, 0.3mm: p=.99).

Our results confirm that there are gender differences in distal radius morphology. Current plate designs incorporate a VCA of 25° which does not match the native VCA of the distal radius in males or females. Although the difference in prominence distance approached statistical significance, there were no statistically significant gender differences in the WSL overlap or the contact threshold values. This lack of statistical significance may be related to the small sample size. This study proposes novel methods of assessing the anatomic fit of current VLPs in a 3D CT-based model that may be used in future studies with a larger sample size. Moreover, this study demonstrated the importance of considering gender differences in distal radius morphology in the design of future generations of implants.