Nerve-sparing dorsal and volar approaches to the radiocarpal joint

Arthroscopic scaphocapitate fusion without bone graft; clinical and radiological outcomes

PURPOSE

Scaphocapitate fusion (SCF) is an important surgical option for carpal pathologies, which are difficult to manage as Kienböck's disease. With the advantages of arthroscopy combined with percutaneous fixation techniques, arthroscopic scaphocapitate fusion can have the best outcome for the patient from a functional perspective. This study aims to evaluate the clinical, radiological, and functional results of arthroscopic SCF.

METHODS

The study included thirty patients with stage IIIB and IIIC Kienböck's disease. The articular surfaces were prepared using arthroscopic burr then fixed by Herbert screw. The mean follows up period was about 29 months.

RESULTS

SCF was achieved in approximately seven weeks. There was a statistically significant difference in pre- and post-operative grip strength and Mayo wrist score.

CONCLUSION

According to our study findings, arthroscopic SCF may be performed with significant improvements and satisfactory clinical and functional results in patients with stage IIIB and IIIC Kienböck's disease.

The Relationship Between the Wrist Flexion Creases and the Volar Radiocarpal Joint: A Cadaveric Study

BACKGROUND

Surgical approaches to the volar radiocarpal joint have historically entailed wide exposure, possibly contributing to poor wound healing and wrist denervation. To avoid wound complications and wrist denervation, minimally invasive and percutaneous approaches to the volar radiocarpal joint have been proposed. To help guide these minimally invasive or percutaneous approaches to the joint, we sought to characterize the relationship between the volar wrist flexion creases and the volar radiocarpal joint. We propose that the wrist flexion creases will be a reliable method for localizing the joint.

METHODS

Ten cadaveric upper-extremity specimens consisting of fingertip to mid forearm were obtained. Measurements from the proximal and distal wrist flexion creases were taken via fluoroscopy and gross dissection.

RESULTS

The wrist flexion creases were located distal to the volar radiocarpal joint in all specimens. The volar radiocarpal joint was located 7 and 16 mm proximal to the proximal and distal wrist flexion creases, respectively. The radiographic anatomy correlated well with the underlying deep anatomy.

CONCLUSIONS

The wrist flexion creases can serve as a reliable superficial landmark for the identification of the volar radiocarpal joint. These landmarks aid clinicians in performing or interpreting a physical examination or in performing minimally invasive or percutaneous approaches to the volar radiocarpal joint.

Treatment of Scaphoid Non-Unions with Custom-Made 3D-Printed Titanium Partial and Total Scaphoid Prostheses and Scaphoid Interosseous Ligament Reconstruction

PURPOSE

Treatment of scaphoid fracture sequelae is still an unsolved problem in hand surgery. Custom-made 3D-printed titanium partial and total scaphoid prosthesis and scaphoid interosseous ligament reconstruction (SLIL) are performed in cases of non-union and isolated aseptic necrosis of the proximal scaphoid pole and when it is impossible to save the scaphoid bone, respectively. This study aims to evaluate the clinical, functional and radiographic results after these two prosthesis implantations.

METHODS

Between January 2019 and July 2020, nine partial and ten total scaphoid prostheses were implanted using custom-made 3D-printed titanium implants. Evaluation criteria included carpal height ratio (CHR), radioscaphoid angle, wrist extension and flexion, radial deviation and ulnar deviation of the wrist, grip strength and pinch strength, Visual Analogue Scale (VAS), the Disabilities of Arm, Shoulder, and Hand (DASH) score, and the Patient-Rated Wrist Evaluation (PRWE).

RESULTS

Clinical, functional, and radiographic improvements were found in all outcomes analyzed for both patient groups. The VAS pain scale obtained the most remarkable improvement at the one-year follow-up. The results of the DASH scores and the PRWE were good, with a great rate of patient satisfaction at the end of the follow-up. SLIL reconstruction also provided excellent stability and prevented a mid-carpal bone collapse in the short- and medium-term follow-up.

CONCLUSIONS

A custom-made 3D-printed titanium partial or total scaphoid prosthesis is a viable solution for patients with scaphoid non-union and necrosis or complete scaphoid destruction in whom previous conservative or surgical treatment has failed.

Dual Construct Fixation of the Scaphoid

Dual construct fixation has been increasingly used in complex peri-articular or peri-prosthetic long bone fractures, those with poor bone quality and in revision situations. We describe the utilisation of a screw-plate construct in the setting of a juxta-articular distal pole scaphoid fracture, review the literature and provide recommendations for future use. Level of Evidence: Level V (Therapeutic).

Intercarpal arthrodesis: A systematic review

Intercarpal arthrodesis is a well-established option to treat various disorders of the carpus, such as localized osteoarthritis, carpal instability, and Kienböck's disease. This is a non-conservative procedure aimed at obtaining a stable and congruent interface between the radius and the proximal carpal row, which restores wrist function by minimizing pain and restoring grip strength. These procedures generally yield good predictable results that are maintained over time. However, all intracarpal arthrodesis procedures cause a loss of wrist range of motion. To optimize outcomes and minimize complications, especially nonunion, this surgery may require a learning curve. A precise surgical technique for preparing the bone surfaces, bringing enough bone graft, and using reliable fixation is essential. Since the late 1960s, several intracarpal arthrodesis procedures have been described. Commonly used fusions target the scaphotrapeziotrapezoid, scaphocapitate, four corners, capitolunate or capitohamatolunate regions. Lesser used fusions focus on specific lesions such as the scapholunate, scapholunocapitate, lunotriquetral and triquetrohamate. Here, we propose a systematic review of the various types of intercarpal arthrodesis procedures described in the literature. After having described each arthrodesis, we specify their indications, the variations of the surgical techniques, and then present an overview of the results and complications. Finally, we discuss how these surgeries affect wrist biomechanics. LEVEL OF EVIDENCE: III.

Chronic Isolated Dorsal Dislocation of the Lunate. A Rare Presentation of Carpal Instability

Isolated dorsal lunate dislocation is a rare injury. Only one case has been reported previously in which the treatment was performed in the chronic stage. In this report, we present the case of a 49-year-old handworker male who presented a dorsal dislocation of the lunate after a traffic accident. He was referred to our clinic 2.5 months later due to an initial misdiagnosis. Surgical treatment was performed and consisted of an open reduction using a nerve-sparing dorsal approach. A complete rupture of the perilunate ligaments and a marked instability of the lunate were detected. Stabilisation of the scapholunate, lunotriquetral and scaphocapitate spaces with a compression screw and Kirschner wires, respectively, was performed. The persistence of pain and functional limitation after the surgery along with an insufficient reduction of the scapholunate space on the X-ray and the development of a fistula on the ulnar edge of the carpus prompted reintervention. A hardware-free total wrist arthrodesis was preferred over other procedures, such as proximal row carpectomy, owing to the important articular damage. At the 3-month follow-up, he was clinically stable, consolidation of arthrodesis was documented and he had returned to his previous activities. Isolated dorsal dislocation of the lunate is a rare lesion. There is no consensus on the management of isolated chronic dislocations of the lunate. The frequent delay in the diagnosis compromises the final outcome of reconstructive techniques and introduces the risk of residual instability, increasing the incidence of chronic pain associated with post-traumatic osteoarthritis. In the case of chronic lesions, treatment with palliative techniques, such as proximal carpectomy or joint arthrodesis, should be considered.

The Dorsal Ligament Complex: A Cadaveric, Histology, and Imaging Study

PURPOSE

The distinction between the dorsal intercarpal (DIC) and dorsal scaphotriquetral (DST) ligaments is imprecise and unclear in the literature. The purpose of our cadaveric study was to define the origins, insertions, and anatomic relationships of the dorsal wrist ligaments and relate these anatomic findings to magnetic resonance imaging (MRI) scans and histology.

METHODS

The study included 17 unmatched fresh-frozen cadaveric specimens (7 male and 10 female), with a mean age of 67.1 years (range, 48-86 years). Wrists with arthritis or carpal malalignment were excluded. Ligaments were dissected and insertion sites were recorded in the radioulnar (width) and proximodistal (length) dimensions, centered at the midpoints of the insertion. Three cadaveric specimens underwent a histologic analysis to demonstrate ligament composition and insertion sites. Three additional cadavers underwent MRI, from which 3-dimensional models were built to model ligament topography.

RESULTS

The conjoined triquetral insertion of the DIC, DST, and dorsal radiocarpal (DRC) measured 88.5 ± 6.4 mm². In each specimen, there were 2 distinct deep and superficial components of intercarpal fibers. The deep component inserted on the lunate with an area of 59.0 ± 5.0 mm². The deep and superficial components diverged as they coursed radially. The superficial component proceeded to the scaphoid ridge, trapezium, and trapezoid, whereas the deep component inserted on the proximal row. The deep fibers blended distally from their lunate insertion with the DST, forming a robust, 2.9 ± 0.8-mm wide extension over the dorsal capitate. The DRC inserted on the lunate, proximal to the DIC and DST insertions, with an area of 23.9 ± 5.4 mm².

CONCLUSIONS

The dorsal ligament complex forms a firm link across the proximal carpal row and the DST provides extension of the proximal row over the capitate.

CLINICAL RELEVANCE

This information can guide surgeons while performing a dorsal approach to the wrist and repairing traumatic ligament disruption.

Is the Dorsal Fiber-Splitting Approach to the Wrist Safe? A Kinematic Analysis and Introduction of the "Window" Approach

PURPOSE

To compare the kinematic effects of the dorsal fiber-splitting approach for scapholunate ligament repair to a dorsal "window" approach that spares all ligaments.

METHODS

We randomized 24 fresh-frozen paired cadaveric forearms to either the dorsal fiber-splitting capsulotomy approach (FSC) or the dorsal window approach (window) following scapholunate interosseous ligament (SLIL) division. Loaded fluoroscopic radiographs were obtained after each of the 4 testing conditions following cyclic loading (200 cycles; 71 N): (1) intact SLIL, (2) SLIL-division, (3) surgical approach, and (4) closure. FSC specimens were randomly allocated to 2 subgroups for closure with either a suture anchor (n = 6) or a simple running suture closure (n = 6). Radiographic parameter measurements included the scapholunate gap, radiolunate angle, scapholunate angle, and dorsal scaphoid translation.

RESULTS

Following the FSC, there were significant alterations in all radiographic parameters when compared with the intact and SLIL-division conditions. The window approach did not result in significant changes in any radiographic parameter. When compared to the window approach, all radiographic parameters of the FSC approach were significantly altered. Following closure with suture anchors in the FSC group, radiographic parameters improved, whereas with standard closure they failed to do so. Despite anchor closure, dorsal scaphoid translation, radiolunate angle, and scapholunate angle all remained elevated compared with scapholunate-divided wrists.

CONCLUSIONS

The FSC produced significant changes in carpal posture under load, including scapholunate diastasis, dorsal intercalated segment instability, and dorsal scaphoid translation in SLIL-deficient wrists. The window approach preserved the critical dorsal ligament stabilizers and did not produce changes in carpal posture.

CLINICAL RELEVANCE

The FSC may create iatrogenic changes in carpal posture that cannot be fully corrected with standard or anchor closure. The window approach does not alter carpal posture and should be considered when performing surgical procedures on the scaphoid or lunate.

A New "Denervation" Technique for Painful Arthritic Wrist

Wrist denervation is, by the way, one of the most performed and long-lasting surgical technique for wrist arthritis. Despite many progresses in upper extremity joint arthroplasty, wrist arthritis remains difficult to treat specially in young patients and heavy manual workers. The aim of this technical article is to describe a new outpatient's procedure in which applying pulsed radio frequency on nerve structure of the wrist could achieve similar clinical results of a wrist denervation without surgical incision.

Innervation of the wrist joint: Literature review and clinical implications

The aim of this study was to review the literature on the innervation of the wrist with an emphasis on pathological and therapeutic aspects. The nerves involved in wrist innervation and their mechanoreceptor endings are described. The literature over the past 30 years includes several topics that are still subjects of discussion and debate and require further research.

A new capsulotomy-based dorsal approach to the wrist: A cadaver study

Using a cadaver study, we described a new dorsal approach to the wrist joint using a "U-shaped with proximal base" capsulotomy. Six fresh adult cadaveric wrists were dissected after intra-arterial silicone injection. We did a dorsal approach to expose the dorsal joint capsule. It was then possible to identify the dorsal radiocarpal and intercarpal ligaments, the dorsal radiocarpal and intercarpal arterial arches, the dorsal branch of the anterior interosseous artery and the terminal branch of the posterior interosseous nerve. Wrist arthrotomy was done using our capsulotomy. In each dissected capsular flap, we always found the individual ligament, vascular, and nerve structures, implying they were intact over their trajectories. The mean surface area of the articular exposure was 945 mm² (range 725-1102 mm²) allowing easy access to the carpal bones and the radiocarpal and midcarpal joint spaces. This surgical approach to the wrist is technically feasible and avoids damaging the dorsal extrinsic ligaments fibers. Keeping the vascularization intact could improve capsular healing, while preserving innervation could maintain wrist proprioception.

Radioulnar joint reconstruction: a novel surgical technique and biomechanical assessment for chronic instability

Purpose

This study aims to describe and biomechanically evaluate a novel technique using a strip of the flexor carpi ulnaris tendon for distal radioulnar joint reconstruction.

Methods

Surgical technique was thoroughly detailed, and a cadaveric biomechanical test was conducted to evaluate sagittal plane stability. Pronosupination range of motion was measured before and after the procedure. Dorsal and volar translation resistances were checked in three situations: with the uninjured triangular fibrocartilage complex, after its complete resection and after the surgical procedure.

Results

For distal radioulnar joint translation, higher values were found both in dorsal and volar translation in situations with an injured triangular fibrocartilage complex, with means equal to 25.4 mm (SD: 9.4 mm) and 26.1 mm (SD: 8.0 mm), respectively. For intact triangular fibrocartilage complex, both dorsal and volar translations averages were 3.4 mm (SD: 0.9 mm) and 4.5 mm (SD: 1.8 mm), respectively. Finally, when evaluating dorsal and volar translations after surgical reconstruction, means were 6.3 mm (SD: 1.3 mm) and 6.8 mm (SD: 0.9 mm), respectively. Regarding supination and pronation range of motion, which ranged from 57.9 to 63.4^o, there were no differences in mean and median measures, when the cadavers with intact and reconstructed triangular fibrocartilage complex were compared (p > 0.05).

Conclusion

Promising mechanical evaluations encourage us to hypothesize that the technique effectively reconstructs the dorsal and volar radioulnar ligaments, preserving pronosupination and maintaining the physiological characteristics of the wrist joint. Clinical comparative studies are still necessary to fully validate this procedure.

Level of evidence

Therapeutic - Level V.

Septic Joints: Finger and Wrist

Infections in the joints of the hand and wrist carry the risk of significant morbidity. Common presenting symptoms include joint redness, swelling, and pseudoparalysis that occurs several days following a penetrating trauma. Diagnostic workup should be expedited, including a laboratory evaluation and arthrocentesis. Imaging, including radiographs, ultrasound, computed tomography, and/or MRI, are helpful tools in diagnosis. Once infection is identified, prompt surgical debridement and antibiotics are required. Once the infection has been managed, hand therapy is initiated to decrease the risk of stiffness. Stiffness is the most common complication following infection; additional reported complications include arthritis, ankylosis, and amputation."

The Authors' Technique for Volar Plating of Scaphoid Nonunion

Internal fixation of the scaphoid using a plate has been reported in the literature as far back as 1977. Recently, a specific plate designed for scaphoids has been developed, which provides considerably more buttress support than intramedullary headless screws, and offers a reliable method of rigid internal fixation for complex fractures. Indications to use such a plate include complex acute fractures, such as those with significant waist comminution or steep reverse oblique fractures, and complex nonunions with central bone loss resulting from failed previous headless screw fixation. This is now the authors' preferred treatment for these injuries.

An Extensile Approach to the Radial Aspect of the Carpus: "The Link Incision"

The structures on the radial side of the wrist and thumb base can be approached by a longitudinal incision on the radial side of the wrist. However, longer longitudinal scars can be cosmetically unacceptable and can result in a scar contracture. It is preferable to curve longer incisions along the Langer's skin lines to achieve better scar characteristics. Curving the incision also enables an extensile approach and provides easy access to the thumb base, radial carpus, and radial wrist joint. We describe our approach as a "Link" between the most common approaches that surgeons are familiar with; the dorsoulnar approach to the thumb metacarpophalangeal joint for ulnar collateral ligament repair and the flexor carpi radialis approach for distal radial fracture fixation. The zone between these two incisions is not as frequently approached. Our incision connects these two well established incisions and we have described a step by step approach to this unfamiliar area. This "Link zone" overlies the thumb trapeziometacarpal joint, scaphotrapeziotrapezoid joint, and the radial styloid. It contains superficial branches of the radial nerve, first extensor compartment tendons, and the deep branch of radial artery in the anatomic snuff box. The "Link incision" is an extensile approach in both the proximal and distal directions.

Ligamento-Muscular Reflex Patterns Following Stimulation of a Thumb Carpometacarpal Ligament: An Electromyographic Study

PURPOSE

The dorsoradial ligament (DRL) is essential for stability of the first carpometacarpal joint (CMC1) and is innervated with nerve endings and mechanoreceptors known to contribute to joint proprioception. The influence of these nerve endings on the neuromuscular stability of CMC1 is not yet known. This study investigated whether a ligamento-muscular reflex pathway is present between the DRL and CMC1 muscles.

METHODS

Ten healthy subjects (5 women and 5 men, mean age 28 years; range, 24-37 years) were included. Four primary CMC1 stabilizing muscles were investigated: the extensor pollicis longus, abductor pollicis longus (APL), abductor pollicis brevis, and first dorsal interosseous. Needle electrodes were inserted into each muscle and a fine-wire electrode was inserted into the DRL. The DRL was stimulated at 200 MHz while EMG activities in the muscles were recorded during isometric tip, key, and palmar pinch. Average EMG values were analyzed to compare prestimulus (t₁) with post-stimulus (t₂) activity.

RESULTS

Poststimulus changes were observed in all 4 muscles and 3 positions tested. During tip pinch we observed mass inhibition with a decrease in all muscle amplitudes. In key pinch we observed a rapid co-contraction response. Rapid inhibitory response of antagonistic musculature was observed during palmar pinch. The APL was the only muscle to react within 20 ms after stimulation.

CONCLUSIONS

We identified CMC1 ligamento-muscular reflexes. The mass inhibition of activity observed during tip pinch indicated a protective ligamento-muscular relation that affects all 4 muscles. The co-contractions observed promote joint stability. The fast response in the APL, coupled with its neuroanatomical proximity to the DRL, indicate a particular role in CMC1 proprioception.

CLINICAL RELEVANCE

Proper ligamentous support and retained innervation is likely important for adequate joint function; their innate functions ought to be considered when planning surgical or orthotic treatments.

Septic Arthritis of the Wrist

Septic arthritis of the wrist is an uncommon condition, but one that can result in substantial morbidity. Timely identification and treatment is critical to patient care. No serum laboratory values have been shown to consistently confirm wrist joint infection. Thus, diagnosis is made based mainly on a thorough patient history, physical examination, and joint aspiration. When infection is suspected, aspiration of the wrist should be performed to confirm the diagnosis. Broad-spectrum antibiotics and joint aspiration or surgery are required to manage the infection and prevent sequelae.

Arthroscopic-Assisted Partial Wrist Arthrodesis

Partial wrist arthrodesis (PWA) is a well-known procedure for treating degenerative or posttraumatic wrist conditions. Four-corner fusion (4CF) is mostly used for scapholunate advanced collapse and scaphoid nonunion advanced collapse. The author performed 39 procedures, including 4CFs, 2-corner fusions, 3-corner fusions, scaphoid-capitate/scaphoid-capitate-lunate fusions, scaphoid-trapezium-trapezoid arthrodeses, and radioscapholunate arthroscopic PWAs (A-PWAs). There were 8 revision cases including 4 partial nonunions. All A-PWAs healed satisfactorily after revision surgery. This article discusses the surgical techniques and tips to avoid mistakes. The pros and cons for open versus arthroscopic techniques and for screws versus Kirschner wires are also discussed.

Four-Year Outcomes of Midcarpal Hemiarthroplasty for Wrist Arthritis

PURPOSE

The purpose of this study was to review the average 4-year outcomes of a cohort of patients with wrist arthritis, treated by a single surgeon with a novel prosthetic hemiarthroplasty of the midcarpal joint. We hypothesized that midcarpal hemiarthroplasty would improve range of motion and grip strength of patients with wrist arthritis, with a complication profile comparable with that of alternative solutions for wrist arthritis.

METHODS

We reviewed a series of 20 patients treated with a midcarpal hemiarthroplasty at an average of 4 years following surgery. Patients were evaluated objectively with grip strength, wrist range of motion, serial radiographs, and subjectively surveyed with Disabilities of the Arm, Shoulder, and Hand (DASH) and Mayo scores.

RESULTS

Range of motion increased by a mean 33° in flexion-extension and 10° in radial-ulnar deviation compared with preoperative range of motion. Mean grip strength improved to 20.8 kg from 14.1 kg, and Mayo and DASH scores also significantly improved. Three patients had a manipulation under anesthesia for stiffness. One patient required open reduction internal fixation of an unstable fourth carpometacarpal joint after falling. Two patients were revised to a total wrist arthroplasty and 1 to a wrist fusion.

CONCLUSIONS

Midcarpal hemiarthroplasty provides improved wrist range of motion, grip strength, and patient-reported outcome scores compared with preoperative values, with a complication profile comparable with that of other surgical options for patients with wrist arthritis. Advantages of midcarpal arthroplasty include retention of the native distal carpal row, preservation of midcarpal motion, as well as the option for conversion to a total wrist arthroplasty should revision be required.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

El papel de la propiocepción y el control neuromuscular en las inestabilidades del carpo

La congruencia articular, la integridad ligamentaria y la compresión de las superficies articulares ocasionada por la contracción muscular se han considerado históricamente los tres pilares básicos para la estabilidad del carpo. En los últimos años se ha propuesto un nuevo factor para explicar los mecanismos de estabilización carpiana, la propiocepción y el control neuromuscular. La propiocepción en la muñeca se origina en órganos sensoriales localizados en los ligamentos y cápsulas articulares (los mecanorreceptores). La estimulación de los mismos inicia un reflejo involuntario que provoca una respuesta muscular selectiva dirigida a proteger la zona de la muñeca donde se ha originado la señal aferente. En este trabajo de revisión se pretende dar a conocer el concepto de propiocepción y control neuromuscular, el papel que tienen en la estabilidad del carpo y las posibles aplicaciones en la práctica clínica.

The role of proprioception and neuromuscular stability in carpal instabilities

Carpal stability has traditionally been defined as dependent on the articular congruity of joint surfaces, the static stability maintained by intact ligaments, and the dynamic stability caused by muscle contractions resulting in a compression of joint surfaces. In the past decade, a fourth factor in carpal stability has been proposed, involving the neuromuscular and proprioceptive control of joints. The proprioception of the wrist originates from afferent signals elicited by sensory end organs (mechanoreceptors) in ligaments and joint capsules that elicit spinal reflexes for immediate joint stability, as well as higher order neuromuscular influx to the cerebellum and sensorimotor cortices for planning and executing joint control. The aim of this review is to provide an understanding of the role of proprioception and neuromuscular control in carpal instabilities by delineating the sensory innervation and the neuromuscular control of the carpus, as well as descriptions of clinical applications of proprioception in carpal instabilities.

Scapholunate instability: proprioception and neuromuscular control

From a kinetic point of view, the wrist is considered stable when it is capable of resisting load without suffering injury. Several prerequisites are necessary for the wrist to be kinetically stable: bone morphology, normal articulating surfaces, ligaments, the sensorimotor system, the muscles crossing the wrist, and all nerves connecting to ligaments and muscles. Failure of any one of these factors may result in carpal instability. The terms "scapholunate (SL) dissociation" and "SL instability" refer to one of the most frequent types of wrist instability, resulting from rupture or attenuation of the SL supporting ligaments. From a radiologic point of view, SL instability may be dynamic or static. Unlike static instabilities, which tend to be painful and dysfunctional, a good proportion of dynamic SL instabilities remain asymptomatic and stable for prolonged periods of time. Such a lack of symptoms suggests that a ligament rupture, in itself, is not enough for a joint to become unstable. Certainly, the process of achieving stability is multifactorial and involves normal joint surfaces, ligaments, muscles, and a complex network of neural connections linking all these elements. In this article, we will review the neuromuscular stabilization of the SL joint and the proprioceptive mechanisms that contribute to the dynamic carpal stabilization.

Antipronation spiral tenodesis--a surgical technique for the treatment of perilunate instability

Perilunate dislocations involve avulsion or rupture of both intrinsic and extrinsic ligaments around the lunate. If inadequately treated, these ligaments may not heal properly, inducing a particular type of carpal instability characterized by the loss of the ability of the carpus to resist pronation torques. Six ligaments protect the carpus against excessive intracarpal pronation: long radiolunate, palmar and dorsal lunotriquetral, dorsal scapholunate, dorsal intercarpal, and palmar scaphocapitate ligaments. Collectively, these antipronation ligaments have a spiral configuration around the carpus. This article describes a technique to reconstruct this spiral arrangement of ligaments using a strip of flexor carpi radialis. To illustrate the technique, we describe 1 clinical case with a follow-up of 34 months. The so-called antipronation spiral tenodesis is only indicated if the instability is easily reducible, without cartilage damage.

Midcarpal hemiarthroplasty for wrist arthritis: rationale and early results

Midcarpal hemiarthroplasty is a novel motion-preserving treatment for radiocarpal arthritis and is an alternative to current procedures that provide pain relief at the expense of wrist biomechanics and natural motion. It is indicated primarily in active patients with a well-preserved distal row and debilitating arthritic symptoms. By resurfacing the proximal carpal row, midcarpal arthroplasty relieves pain while preserving the midcarpal articulation and the anatomic center of wrist rotation. This technique has theoretical advantages when compared with current treatment options (i.e., arthrodesis and total wrist arthroplasty) since it provides coupled wrist motion, preserves radial length, is technically simple, and avoids the inherent risks of nonunion and distal component failure. The KinematX midcarpal hemiarthroplasty has an anatomic design and does not disrupt the integrity of the wrist ligaments. We have implanted this prosthesis in nine patients with promising early results. The indications for surgery were as follows: scapholunate advanced collapse wrist (three), posttraumatic osteoarthritis (three), inflammatory arthritis (two), and Keinböck disease (one). Prospective data has been collected and the results are preliminary given the infancy of the procedure. The mean follow-up was 30.9 weeks (range: 16 to 56 weeks). The mean Mayo wrist score increased from 31.9 preoperatively to 58.8 (p < 0.05) and the mean DASH score improved significantly from 47.8 preoperatively to 28.7 (p < 0.05). There was a trend toward increased motion but statistical significance was not reached. Two patients required manipulation for wrist stiffness. There was no evidence of prosthetic loosening or capitolunate narrowing. The procedure is simple (average surgical time was 49 minutes) and maintains coupled wrist motion through preservation of the midcarpal articulation. The preliminary data show that it appears safe but considerably longer follow-up is required before conclusions can be drawn as to its durability, reliability, and overall success. The level of evidence for this study is therapeutic level IV (case series).

Elongation of the dorsal carpal ligaments: a computational study of in vivo carpal kinematics

PURPOSE

The dorsal radiocarpal (DRC) and dorsal intercarpal (DIC) ligaments play an important role in scapholunate and lunotriquetral stability. The purpose of this study was to compute changes in ligament elongation as a function of wrist position for the DRC and the scaphoid and trapezoidal insertions of the DIC.

METHODS

We developed a computational model that incorporated a digital dataset of ligament origin and insertions, bone surface models, and in vivo 3-dimensional kinematics (n = 28 wrists), as well as an algorithm for computing ligament fiber path.

RESULTS

The differences between the maximum length and minimum length of the DRC, DIC scaphoid component, and DIC trapezoidal component over the entire range of motion were 5.1 ± 1.5 mm, 2.7 ± 1.5 mm, and 5.9 ± 2.5 mm, respectively. The DRC elongated as the wrist moved from ulnar extension to radial flexion, and the DIC elongated as the wrist moved from radial deviation to ulnar deviation.

CONCLUSIONS

The DRC and DIC lengthened in opposing directions during wrist ulnar and radial deviation. Despite complex carpal bone anatomy and kinematics, computed fiber elongations were found to vary linearly with wrist position. Errors between computed values and model predictions were less than 2.0 mm across all subjects and positions.

CLINICAL RELEVANCE

The relationships between ligament elongation and wrist position should further our understanding of ligament function, provide insight into the potential effects of dorsal wrist incisions on specific wrist ranges of motion, and serve as a basis for modeling of the wrist.

The anterolateral corner of the radial metaphysis as a source of bone graft for the treatment of scaphoid nonunion

As a source of corticocancellous grafts for treating scaphoid nonunions, the anterolateral corner of the distal radial metaphysis has several advantages over other alternatives: it provides good-quality corticocancellous bone, it allows one to harvest the graft and treat the scaphoid through the same incision, it does not require general anesthesia, and it has less morbidity than occurs when obtaining the graft from the iliac crest.

The scapholunate interosseous ligament afferent proprioceptive pathway: a human in vivo experimental study

PURPOSE

To examine the afferent pathways of the scapholunate interosseous ligament (SLIL)-generated stimuli and their contribution to the overall carpal proprioception.

METHODS

We examined 5 selected patients with preganglionic global root avulsion, confirmed by previous brachial plexus exploration, during the initial stage of carpal arthrodesis surgery. Despite their anesthetic-flail extremity, both the distal axon and the ganglionic cell were intact and able to transfer afferent stimuli. We placed electrodes subcutaneously over the adjacent areas of the ulnar, median, and radial nerves at the elbow region and performed an intraoperative neurophysiologic study. We studied the homologous sensory action potentials (SAPs) generated at the wrist in relaxation, flexion, extension, radial deviation, and ulnar deviation positions at each nerve and repeated them in 2 stages. The first took place with the SLIL intact and the second with the SLIL lacerated. The noise from the rest of the wrist elements was digitally eliminated.

RESULTS

After the SLIL laceration, SAP intensities recorded at the median nerve in every wrist position were reduced. The radial and ulnar nerves showed differences of lesser degrees between the recorded SAP intensities before and after the ligament sectioning in every carpal position, with only the radial nerve following a specific pattern. The SAP intensity recorded at the median nerve in every carpal motion after the SLIL laceration was similar to the SAP intensity at relaxation with the SLIL intact, whereas recordings of various intensities were present for the radial and ulnar nerves.

CONCLUSIONS

The SLIL generates proprioceptive stimuli at every wrist position. The main innervation of the whole SLIL derives from the anterior interosseous nerve; a partial contribution of the posterior interosseous nerve focused on the dorsal subregion of the ligament may also be present.