Biohacking and Chip Implantation in the Human Hand: An Introduction.

Biohacking is a term used to describe people making changes to their bodies to improve their well-being. This includes the implantation of radiofrequency identification implants. This technology for wireless communication is already incorporated into our daily lives as in the use of contactless payment and badges to open doors. Since the first radiofrequency identification implantation in a human in 1998, the possibilities of this technology have dramatically increased, and the number of persons that have been chipped is growing. The hand seems to be the most popular body part to implant these chips because it can easily be positioned close to a reader. Currently, implantation is typically not performed in a medical environment. However, implantation of these devices in humans can result in complications, such as infection and tendon attrition, and the relevant safety implications have not been extensively studied. The scope of this review was to inform the hand surgeon community about the existence of these implants, why they are used, and to open the debate about the possible future role of the hand surgeon in safely implanting these devices and dealing with possible complications.

Analysis of trapeziometacarpal prosthesis cup position with respect to the trapezial anatomy.

The purpose of this study was to analyse the anatomy of the trapezium with regard to cup position in trapeziometacarpal replacement and identify those trapeziums that are at risk of cup perforation through the trapezoid articular surface. The width of the proximal and distal articular surface and the height of the trapezium and second metacarpal facet were measured on 96 peritrapezial views reconstructed from computed tomography scans. The trapezoid articular surface of the trapezium (TRAST) angle was calculated, and four different cup designs were virtually positioned centrally in the trapezium and parallel to the proximal articular surface. Risk of perforation was defined as a cup that exceeds the ulnar border of the proximal articular surface. The mean TRAST angle in our study was 33°. Risk of perforation is higher when the second metacarpal facet is smaller than 5 mm and when the TRAST angle is 35° or more. In these cases, the position of the cup should be more radial or more distal.

Intramedullary headless compression screw fixation of the middle phalanx: tips, tricks, and pitfalls.

This report emphasizes careful consideration of surgical technique for intramedullary screw fixation in middle phalanx fractures. Highlighting pitfalls, particularly with K-wire placement, it suggests the antegrade trans-articular approach as superior, urging further research for improved patient outcomes.

Comparison of time-efficiency of individually wrapped screws and sterile screw racks in distal radius fracture treatment.

INTRODUCTION: Time-efficiency of individually wrapped screws versus screws in a screw rack is not well established. MATERIALS AND METHODS: We performed a prospective single-center clinical study timing the interval between the surgeon asking and receiving a screw during plate and screw osteosynthesis of distal radius fractures. Patients were randomized for individually wrapped screws or screws in a screw rack. The study was conducted in a Level 1 Trauma Center and surgeries were performed between March and June 2023. RESULTS: Average handling time for screws from a screw rack was 9 s (SD 5.5; range 3-28) and 22 s for individually wrapped screws (SD 6.1; range 6-38). This average difference of 13 s is significant (p < 0.0001). CONCLUSION: There is a significant increase in handling time using individually wrapped screws over using a screw rack. LEVEL OF EVIDENCE: Level I (therapeutic, randomized controlled trial).

Polyethylene liner fracture in dual mobility trapeziometacarpal total joint replacement: how to make a timely diagnosis?

We present a case of fracture of the polyethylene liner of a dual-mobility trapeziometacarpal total joint arthroplasty. Standard radiographic imaging was normal. This case highlights the importance of dynamic radiographic imaging to make a timely diagnosis.

Does trapezium remodeling correlate with cup shape?

We investigated whether trapezium bone reaction was different following implantation of a trapeziometacarpal total joint replacement with a hemispheric or a conical cup. Fifty-three Keri Medical Touch implants with hemispheric cup and 53 with conical cup were prospectively followed up radiographically. We compared radiographs taken immediately and one year after surgery for cup subsidence, tilt, heterotopic ossification and loosening. Cup subsidence of at least 1 mm was detected in 4% of cases for both cup types. Additive bone reaction around the cup of more than 1 mm was present in 62% of conical cups and 47% of hemispheric cups. These were minor and there were no large ossifications with risk of impingement. Minor radiolucency was seen superficially at the implant-bone interface of 13% of the hemispheric cups and 9% of the conical cups. None of these bone reactions differed significantly according to cup design.

Total joint replacement for osteoarthritis of the carpometacarpal joint of the thumb: why and how?

Total joint replacement has certain advantages over other surgical treatment methods for osteoarthritis of the thumb carpometacarpal joint, including restoration of thumb length and alignment, good cosmetical result, fast recovery of hand function and prevention of iatrogenic complications at neighbouring joints. Disadvantages include the technical difficulty to perform this surgery and a possible higher complication rate. A meticulous surgical technique is mandatory. Combined with a cementless and modular ball-in-socket implant with a metal-on-polyethylene friction couple, a 10-year survival rate higher than 90% can be expected. Revision surgery is possible with implant exchange or conversion to trapeziectomy.

Evaluation of MRI Signal Changes of the Distal Biceps Tendon in Asymptomatic Patients.

PURPOSE: Magnetic resonance imaging (MRI) is used widely for complete ruptures of the distal biceps tendon. The validity of this investigation for bicipital bursitis and tendinosis is unknown. The purpose of present study was to assess the prevalence of incidental (asymptomatic) signal changes in the distal biceps tendon in patients who underwent MRI including the elbow. Our null hypothesis was that signal changes of the distal biceps tendon do not occur in asymptomatic patients. This would empower MRI as a diagnostic tool for bicipital bursitis and tendinosis as well as complete and partial distal biceps tendon ruptures. METHODS: We evaluated 1,191 elbow MRI scans including the distal biceps tendon insertion. The prevalence of incidental findings was calculated and sensitivity, specificity, positive predictive value, negative predictive value, false positive probability, and false negative probability were calculated. RESULTS: Signal changes of the distal biceps tendon or bursitis were identified in 8 of 1,191 asymptomatic patients (prevalence 0.6%). The sensitivity of MRI for distal biceps pathology was 97% (95% confidence interval [CI], 93%-99%), specificity 99% (95% CI, 98%-99%), positive predictive value 94% (95% CI, 89%-97%), negative predictive value 99% (95% CI, 99%-99%), false positive probability 6% (95% CI, 3%-10%), and false negative probability 0.3% (95% CI, 0.1%-0.9%). There was no correlation between explanatory variables, including age, sex, race, occupation, and inflammatory disease and incidental distal biceps tendon signal changes. CONCLUSIONS: The prevalence of distal biceps tendon signal changes on MRI in asymptomatic patients is very low. CLINICAL RELEVANCE: The negative predictive value of 99% shows that patients without signal changes on MRI may be assumed to have no distal biceps tendon pathology. MRI investigation of distal biceps tendon is a valuable tool in the diagnosis of tendinosis and bicipital bursitis.

Reconstruction of flexor pollicis longus tendon with palmaris longus interposition graft: results in 14 patients.

The flexor pollicis longus tendon is prone to attritive rupture and retraction. Direct repair is often not possible. Interposition grafting is a treatment option to restore tendon continuity, although the surgical technique and postoperative results have not been well defined. We report our experience with this procedure. 14 patients were prospectively followed for a minimum of 10 months after surgery. There was one postoperative failure of the tendon reconstruction. Postoperative strength was comparable to the contralateral side, but thumb range of motion was significantly reduced. In general, patients reported excellent postoperative hand function. This procedure seems a viable treatment option with lower donor site morbidity than tendon transfer surgery.

In vivo evaluation of a new intramedullary distal biceps tendon fixation device.

BACKGROUND: Intramedullary fixation in distal biceps tendon repair may be a solution to address specific shortcomings of current fixation techniques. Most investigations are limited to biomechanical evaluation. The purpose of this study was to report the short-term outcomes of an intramedullary fixation device. METHODS: We evaluated functional and radiographic outcomes at up to 6 months of follow-up. Patients with an acute distal biceps tendon rupture eligible for surgical repair were invited to take part in the study. Ten patients were included in the final analysis. All patients were evaluated both clinically and radiographically at 2 weeks, 6 weeks, 3 months, and 6 months. Outcomes were recorded using a visual analog scale score for pain, the Mayo Elbow Performance Score, and the Disabilities of the Arm, Shoulder and Hand score. Radiographic evaluation comprised radiographic and computed tomography evaluation. RESULTS: There were no failures of fixation in the patient group examined. Elbow mobility was symmetrical for all patients from 3 months onward. Supination strength was 86% of the uninjured side at final follow-up. The mean Disabilities of the Arm, Shoulder and Hand score and Mayo Elbow Performance Score at final follow-up were 0 and 100, respectively. Computed tomography images showed no signs of button migration, cortical thinning due to button pressure, or button breakout. The tendon could be followed to the button in all cases. CONCLUSIONS: The intramedullary fixation button technique to repair the distal biceps tendon has excellent functional outcomes at 6 months. No adverse reactions of the button on the bone were seen. As this technique minimizes the risk of posterior interosseous nerve injury and has a sufficient bone tunnel to avoid gap formation, this may be a promising new technique for distal biceps tendon rupture refixation.

In vitro Biomechanical Analysis of Proximal Phalangeal Osteotomy Fixation.

Background Corrective osteotomies of the proximal phalanx are typically stabilized with plate and screws. Although intramedullary headless screws form an alternative fixation method in the treatment of acute phalangeal fractures, reports about fixation of opening wedge corrective osteotomies with these implants are lacking. Objective The goal of the present study was to biomechanically compare the failure force of both fixation methods for this specific indication. Methods Twenty-four cadaver phalanges were equally distributed between apex volar and apex lateral opening wedge osteotomy groups. In each group, half of the osteotomies were fixed with a 1.3-mm dorsal locking plate, the other half with a 2.4-mm intramedullary headless screw. A three-point bending test was performed. Results The mean maximal failure force after apex lateral osteotomy was 178.4 N for the plate-screw construct and 144.0 N after intramedullary headless screw fixation. After apex volar osteotomy, mean maximal force was 237.6 N in the plate-screw group and 160.9 N in the intramedullary headless screw group. Mean stiffness after apex lateral osteotomy was 63.3 N/mm in the plate-screw group, and 55.9 N/mm in the intramedullary headless screw group. Mean stiffness after apex volar osteotomy was 197.5 N/mm and 60.0 N/mm for the plate-screw and intramedullary headless screw group, respectively. Conclusion For apex volar osteotomies, dorsally applied angular stable plate and screws provide significantly stronger fixation than intramedullary headless screws. For apex lateral osteotomies, fixation force is comparable. Clinical relevance These data are useful when considering fixation of opening wedge osteotomies with intramedullary screws.

Scaphoidectomy and 4-corner arthrodesis with headless compression screws: results, complications and their treatment.

Scaphoidectomy and 4-corner arthrodesis is a common salvage surgery for degenerative wrist pathology. The purpose of this study was to evaluate the results of this procedure performed with headless compression screws, with a special focus on postoperative complications and their treatment. We assessed 36 wrists in 31 patients that were treated between 2009 and 2017. Mean follow-up was 5.2 years (range 2.9- 9.4). Pain was expressed on a Visual Analog Scale. The Quick Disabilities of the Arm, Shoulder and hand (qDASH) questionnaire and Michigan Hand Outcome Questionnaire (MHOQ) were used to assess patient functionality and satisfaction. Range of motion and grip strength of both wrists were measured. Radiographs of the operated wrist were evaluated. Mean pain score was 1.5 ± 2.3 with 19% of patients being completely free of pain also during activity. Mean qDASH was 44 ± 20 and mean MHOQ was 10 ± 5. Mean flexion-extension arc of the operated wrist was 69° and 61% of the contralateral wrist. Mean grip strength was 35kg and 89% of the opposite wrist. Non-union was observed in two patients. Two patients required hardware removal and in three patients a pisiformectomy was performed. Conversion to total wrist arthrodesis was needed in one patient. We observed postoperative complications in 28% of our patients. Most complications can successfully be treated with additional surgery. The presence of pisotriquetral arthritis should be assessed before surgery and treated with pisiform excision.

Minimally Invasive Corrective Osteotomy for Metacarpal Malrotation.

Metacarpal fractures can be complicated by malrotation. This can cause functional problems with overriding or underriding of the fingers with flexion. Surgical treatment consists of corrective osteotomy and derotation. This is typically performed open and different techniques for osteotomy and fixation have been described. Postoperative complications include finger stiffness and hardware irritation. We propose a technique for minimally invasive corrective osteotomy of malunited metacarpal fractures with rotational malalignement. Advantages are quick rehabilitation and no prominent hardware.

A new intramedullary fixation method for distal biceps tendon ruptures: a biomechanical study.

BACKGROUND: Various techniques have been described for distal biceps tendon reinsertion. Although high success rates have been reported, all current techniques have specific shortcomings, with complications such as heterotopic ossification, nerve damage, and gap formation. The purpose of the present study was to biomechanically evaluate a new intramedullary fixation device that might reduce the risk of posterior interosseous nerve lesions. We therefore compared the fixation strength of this new intramedullary button with an extramedullary placed classic extracortical button. METHODS: A standard bicortical button was compared to the new intramedullary fixation device using fresh-frozen cadaveric specimens. The fixation strengths were tested both cyclically and statically. Load to failure and method of failure were also recorded. RESULTS: There were no failures during the cyclic load testing. The mean tendon-bone displacement was 0.87 ± 0.13 mm for the bicortical group and 0.83 ± 0.13 mm for the new button. During static loading, the mean load to failure for the bicortical group was 296 ± 97 N, whereas the new button group showed a higher mean load to failure of 356 ± 37 N. Breakout through the anterior cortex was recorded in 2 of 6 bicortically placed buttons and 1 of 6 in the new device. CONCLUSIONS: The new intramedullary fixation device yields comparable loads to failure compared with currently used techniques in a biomechanical setup. These findings together with the theoretical advantages suggest that this technique may be a valuable solution for the repair of distal biceps tendon rupture.

The effect of cup orientation on stability of trapeziometacarpal total joint arthroplasty: a biomechanical cadaver study.

It has been suggested that the cup of a trapeziometacarpal total joint replacement should be positioned parallel with the proximal articular surface of the trapezium to align it with the centre of motion. This would diminish the chance of dislocation. The goal of this study was to test this idea biomechanically. A linked trapeziometacarpal prosthesis was implanted in seven cadaver hands and combined with three-dimensional printed trapezium cups in 17 different orientations. For every combination, stability of the prosthesis was assessed through its entire passive range of motion. Dorsal inclination of the cup relative to the proximal articular surface increased the risk of dislocation with thumb flexion and opposition. The risk of dislocation was also increased with lateral or medial inclination of the cup exceeding 20°. Our results demonstrate that cup orientation is an important factor in prosthetic joint stability. Cup placement parallel to the proximal articular surface is ideal.

Effect of Bupivacaine Liposome Injectable Suspension on Sensory Blockade and Analgesia for Dupuytren Contracture Release.

Purpose: To study the efficacy of bupivacaine liposome injectable suspension in prolonging sensory blocks of the median and ulnar nerves for subjects with Dupuytren contracture release by collagenase injection. We hypothesized that combining liposome bupivacaine and bupivacaine hydrochloride would extend the duration of blocks without added complications. Methods: We randomized 32 subjects scheduled for Dupuytren contracture release with collagenase Clostridium histolyticum injections to receive forearm blocks of the median and ulnar nerves with a mixture of 5 mL liposome bupivacaine 1.33% plus 2.5 mL bupivacaine hydrochloride 0.5% per nerve (n = 16) or 7.5 mL bupivacaine hydrochloride 0.5% alone per nerve (n = 16). Sensory block and analgesia were assessed through the first posttreatment week. Results: Sensory block was nearly 4 times longer in subjects who received the liposome bupivacaine mixture compared with subjects who received bupivacaine hydrochloride alone. Most subjects (13 of 16) who received the liposome bupivacaine mixture had adequate analgesia for finger manipulation to rupture the cords, whereas most subjects (15 of 16) who received bupivacaine hydrochloride alone required additional anesthesia. Subjects in the liposome mixture group reported lower pain scores through the first 3 days after treatment. There were no serious side effects. Conclusions: Addition of liposome bupivacaine to forearm blocks for Dupuytren contracture release prolonged sensory block and improved pain scores without increasing side effects or impairing hand function. Supplemental lidocaine injections for the painful phases of Dupuytren contracture release with collagenase C histolyticum injections were not required by most subjects who received liposome bupivacaine. Type of study/level of evidence: Therapeutic I.