Metacarpophalangeal Joint Pyrocarbon Arthroplasty for Osteoarthritis: An Analysis of 44 Arthroplasties

PURPOSE

The objective of this study was to analyze postoperative outcomes in a group of patients who underwent metacarpophalangeal (MCP) arthroplasty using a pyrocarbon prosthesis for noninflammatory arthritis.

METHODS

An analysis of 44 MCP joint arthroplasties in 30 patients with >2 years of follow-up over a 12-year period was reviewed. The mean age was 63 years. The primary operative indication was pain and stiffness from osteoarthritis refractory to nonsurgical management.

RESULTS

At a mean follow-up of 6 ± 3 years, 8 (18%) joints underwent reoperation, including 5 (11%) that underwent revision arthroplasty. The 2- and 5-year rates for survival free of revision arthroplasty were 95% and 93%, respectively. One (2%) operation was complicated by intraoperative fracture. Postoperative complications occurred in 8 (18%) fingers and included ligament/tendon rupture (n = 3) and instability (n = 2). There was significant postoperative improvement in pain levels, MCP arc of motion, pinch strength, and grip strength. At a mean 5 years of radiographic follow-up, 7% had progressive implant instability because of grade 3 or greater loosening. No joints experienced implant instability from progressive subsidence.

CONCLUSIONS

Metacarpophalangeal arthroplasty using a pyrocarbon implant for osteoarthritis demonstrates an 7% revision rate at 5 years after surgery. Complications lead to reoperation in 1 of 5 arthroplasties. Radiographic evidence of implant instability was uncommon. Overall, patients experienced predictable pain relief and improvements in their range of motion and pinch strength.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Radial Collateral Ligament Laxity of Thumb Metacarpophalangeal Joint Following Trapeziometacarpal Arthrodesis

PURPOSE

Trapeziometacarpal (TM) arthrodesis may increase adduction motion of the thumb metacarpophalangeal (MCP) joint, causing radial collateral ligament laxity. Stability of the MCP joint is important to the long-term functional outcome after TM arthrodesis. This study assessed preoperative and postoperative radial collateral ligament laxity using dynamic radiographs to confirm whether laxity was exacerbated after surgery and examined whether there is a relationship between the fixation angle of arthrodesis and the degree of laxity.

METHODS

Forty-four thumbs in 33 patients who underwent TM arthrodesis and were followed for at least 5 years were studied. Dynamic radiographs in radial adduction-abduction and palmar adduction-abduction were obtained. We defined the midpoint of arc of motion as the fixation angle of arthrodesis in the radial and palmar planes. We measured the intersection angle between longitudinal axis of the first metacarpal (M1) and that of thumb proximal phalanx (P1). P1M1 angle in a palmar adduction view of dynamic radiographs reflected radial collateral ligament laxity in palmar adduction (adduction P1M1 angle). We subtracted a preoperative adduction P1M1 angle from a postoperative adduction P1M1 angle and defined its value as an exacerbated adduction P1M1 angle.

RESULTS

Adduction P1M1 angle increased from 9° ± 5° to 18° ± 10°. The median exacerbated adduction P1M1 angle was 7°. Ten thumbs (23%) developed ulnar subluxation of MCP joint in the palmar adduction view of dynamic radiographs. Among them, two thumbs developed osteoarthritis of MCP joint (5%). Fixation angle of the arthrodesis was a mean of 35° ± 7° and 32° ± 9° in the radial arc and palmar arc planes, respectively. There was a positive correlation between increasing adduction P1M1 angle and TM arthrodesis in an increasingly palmarly abducted position.

CONCLUSIONS

Radial collateral ligament laxity of thumb MCP joint was exacerbated after TM arthrodesis. Greater fixation angle in palmar abduction resulted in more laxity of the joint.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Spontaneous Idiopathic Bilateral Sagittal Band Rupture: A Case Report

Introduction

Extensor tendon subluxation or dislocation resulting from sagittal band rupture can be associated with snapping, catching, locking, pain, and swelling of the finger. Several etiologies were reported in the literature, with frequent mention of a traumatic rupture caused by a direct blow at the level of the metacarpophalangeal joint (MCPJ). The other causes of sagittal band injuries are degenerative disease, congenital infection, and rheumatoid arthritis. To our knowledge, we report the first case of spontaneous idiopathic bilateral sagittal band rupture.

Case Report

We, herein, present the case of a seronegative 29-year-old female who presented with pain and swelling in the dominant hand for 4 days.

Conclusion

Upon examination, she was found to have bilateral dislocation of the extensor tendons at the level of the (MCPJ) of the third and fourth digits. Any underlying cause was excluded, and the diagnosis was confirmed with a dynamic ultrasound study.

Painful snapping of the middle finger caused by hyperplasia of the ulnar lateral band: A case report

Snapping of fingers can be caused by pathologies such as stenosing flexor tenosynovitis. However, snapping symptoms in the metacarpophalangeal (MP) joint caused by hypertension and hyperplasia of the lateral band are rare. We present a 26-year-old female with symptoms of painful snapping of the middle finger. When the finger was actively flexed from the hyperextension of the MP joint, the ulnar lateral band was prominent, and a snapping phenomenon occurred. The cause of the snapping finger was considered to be tightness of the ulnar lateral band, and surgery was planned. Intraoperatively, the ulnar lateral band was tense and hyperplastic. The snapping phenomenon disappeared immediately after the resection of the lateral band. It is important to consider this condition as one of the differential diagnoses of snapping finger when the patient complains of an atypical snapping phenomenon.

Surgical Treatment of a Neglected Thumb Volar Plate Injury in an 11-Year-Old Girl: A Case Report

BACKGROUND Volar plate injuries are rare and difficult to diagnose and treat. Only a few cases have been described on the thumb, especially in children, that resulted in swan-neck type deformity. Conservative treatment has been suggested as first-line management, but surgical reconstruction utilizing flexor digitorum superficialis tenodesis has been described for refractive cases. Only a few attempted surgical repairs of the volar plate have been reported, since it is a technically demanding procedure. CASE REPORT We present the case of a neglected thumb volar plate injury in an 11-year-old girl after a thumb hyperextension injury. The patient presented 2 months after her injury with functional disability of her thumb. Magnetic resonance imaging had been performed, with no signs of volar plate injury, and she was consequently treated with an extension-blocking splint, with no effect. Clinical examination raised the suspicion of a thumb volar plate injury, which was confirmed during surgical exploration. Therefore, fixation with a bone anchor was performed, and the metacarpophalangeal joint was immobilized in 20° flexion with a percutaneously inserted Kirschner wire. After splinting for 3 weeks, the patient had 10 sessions of physical therapy. At 6-week follow-up, she presented with excellent active and passive range of motion and absence of pain. CONCLUSIONS Magnetic resonance imaging did not have high sensitivity. Six weeks after surgery, full range of motion was achieved, with no stiffness or tenderness at the first metacarpophalangeal joint, suggesting that a thumb volar plate injury had been managed surgically with a suture anchor with excellent results.

Comparison of 18 F-sodium fluoride positron emission tomography and computed tomography for imaging of the fetlock in 25 nonracehorses

BACKGROUND

18 F-sodium fluoride (18 F-NaF) positron emission tomography (PET) has been validated as a useful imaging technique in the racehorse fetlock. The use of 18 F-NaF PET in the nonracehorse fetlock has not been reported.

OBJECTIVES

To describe 18 F-NaF PET findings in nonracehorse fetlocks, to compare with computed tomography (CT) findings and to compare PET findings between horses with and without fetlock pain.

STUDY DESIGN

Retrospective observational study.

METHODS

All horses undergoing 18 F-NaF PET and CT imaging of the fetlock between October 2016 and March 2021 were included in the study. Medical records were reviewed for associated lameness information.

RESULTS

Thirty-six fetlocks (33 front and 3 hind) from 25 horses were included. The interobserver agreement for PET [0.62 (95% confidence interval [CI] 0.59-0.65)] was higher than for CT [0.47 (95% CI 0.43-0.51)]. Increased 18 F-NaF uptake was most common in the medial subchondral bone of the proximal phalanx (23/36), the dorsomedial (20/36) and dorsosagittal (16/36) metacarpal/metatarsal distal subchondral bone, whereas sclerosis was identified on CT in these areas in 22 of 36 (p > 0.9), 33 of 36 (p = 0.001) and 23 of 36 (p = 0.15), respectively. Significant correlations were found between PET grades and both subchondral sclerosis and resorption CT grades (p < 0.001, Spearman r = 0.19 and 0.21, respectively). Abnormal 18 F-NaF uptake in the proximal sesamoid bones (PSBs) was identified in 12 of 36 of the fetlocks, which was more common than CT abnormalities (3/36, p = 0.02). Periarticular increased uptake was seen in 7 of 36 fetlocks, whereas osteophytosis was recognised on CT in 20 of 36 (p = 0.1). Maximal standardised uptake values (SUVmax) were significantly higher in painful than in nonpainful fetlocks (22.0 and 11.9, respectively, p = 0.038).

MAIN LIMITATIONS

Retrospective study and limited sample size.

CONCLUSIONS

Overall PET and CT findings follow a similar distribution in their location. PET identified more abnormalities in the PSBs than CT. SUVmax is a pertinent factor to take into consideration for the assessment of the clinical significance of findings.

Ultrasound versus MRI in the evaluation of the thumb metacarpophalangeal joint

An intricate and unique combination of ligamentous, fibrocartilaginous, and osseous structures stabilize the thumb metacarpophalangeal joint. Both ultrasound and high-resolution magnetic resonance imaging are extremely useful in evaluating these critical structures. This article reviews common injuries of the thumb metacarpophalangeal joint, while highlighting the merits, limitations, and pitfalls of the two imaging modalities. A clear appreciation of each method, paired with anatomic knowledge, will lend greater confidence and accuracy to diagnosing impactful injuries and guiding intervention.

Return to Sport and Performance After Thumb Metacarpophalangeal Joint Collateral Ligament Surgery in the National Basketball Association

Introduction Basketball players are at increased risk of thumb collateral ligament injury (ulnar collateral ligament (UCL) and radial collateral ligament (RCL)). Methods The National Basketball Association (NBA) players with thumb collateral ligament surgery were identified using publicly available data. Performance statistics, ligament injuries (UCL or RCL), return to sport (RTS) time, laterality, and injury dates were recorded. Cases were matched 1:1 with controls based on age (±1 year), body mass index (BMI), NBA experience (±1 year), and performance statistics prior to the index date. RTS was defined as playing in one NBA game postoperatively. Career longevity was evaluated. Summary statistics were calculated, and Student's t-tests (ɑ = 0.001) were performed. Results All 47 players identified with thumb collateral ligament surgeries returned to sport. Thirty-three players (age: 26.9 ± 3.0) had one year of postoperative NBA experience for performance analysis. Career length (case: 9.6 ± 4.1, control: 9.4 ± 4.3, p > 0.001) was not significantly different from controls (p > 0.001). The same season time to RTS (n = 20) was 7.1 ± 2.4 weeks. Off-season or season-ending surgery (n = 13) RTS time was 28.4 ± 18.7 weeks. Neither thumb collateral ligament (UCL, n = 7; RCL, n = 10; unknown, n = 16) had an identifiable difference between the groups when evaluating career length. Career length, games/season, and performance were not different for players who underwent surgery on their dominant thumb (63.6%, 21/33) compared to controls (p > 0.001). Conclusion RTS rate is high in NBA athletes undergoing thumb collateral ligament surgery. Players do not experience decreased performance or career length due to thumb collateral ligament surgery, regardless of a dominant or non-dominant thumb injury.

Denervation as a Treatment for Arthritis of the Hands: A Systematic Review of the Current Literature

Joint denervation has been proposed as a less invasive option for surgical management of hand arthritis that preserves joint anatomy while treating pain and decreasing postoperative recovery times. The purpose of this systematic review was to investigate the efficacy and safety of surgical joint denervation for osteoarthritis in the joints of the hand. EMBASE, MEDLINE, and PubMed databases were searched from January 2000 to March 2019. Studies of adult patients with rheumatoid arthritis or osteoarthritis of the hand who underwent joint denervation surgery were included. Two reviewers performed the screening process, data abstraction, and risk of bias assessment (Methodological Index for Non-Randomized Studies). This review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was registered with PROSPERO (#125811). Ten studies were included, 9 case series and 1 cohort study, with a total of 192 patients. In all studies, joint denervation improved pain and hand function at follow-up (M = 36.8 months, range = 3-90 months). Pooled analysis of 3 studies on the first carpometacarpal joint showed a statistically significant (P < .001) reduction in pain scores from baseline (M = 6.61 ± 2.03) to postoperatively (M = 1.69 ± 1.27). The combined complication rate was 18.8% (n = 36 of 192), with neuropathic pain or unintended sensory loss (8.8%, n = 17 of 192) being the most common. This review suggests that denervation may be an effective and low-morbidity procedure for treating arthritis of the hand. Prospective, comparative studies are required to further understand the outcomes of denervation compared with traditional surgical interventions.

In Vivo Metacarpophalangeal Joint Kinematics After Silicone Implant Arthroplasty in Patients With Rheumatoid Arthritis

PURPOSE

The aim of this study was to determine the potential mechanism of implant fracture using 3-dimensional motion analysis of patients with rheumatoid arthritis.

METHODS

Active flexion motion in 9 hands (34 fingers) of 6 female patients with rheumatoid arthritis who previously underwent hinged silicone metacarpophalangeal joint arthroplasty was examined using 4-dimensional computed tomography. Positions of the proximal phalanges relative to the metacarpals were quantified using a surface registration method. The deformation of the silicone implant was classified in the sagittal plane in the maximum flexion frame. The longitudinal bone axis of the proximal phalanx and the helical axis of the proximal phalanx were evaluated in 3-dimensional coordinates based on the hinge of the silicone implant.

RESULTS

Nineteen fingers were classified into group 1, in which the silicone implant moved volarly during flexion without buckling of the distal stem. Twelve fingers were classified into group 2, in which the distal stem of the silicone implant buckled. Three fingers were classified into group 3, in which the base of the distal stem had already fractured. Quantitatively, the longitudinal bone axes of the proximal phalanges were displaced from dorsal to volar in the middle stage of flexion and migrated in the proximal direction in the late phase of flexion. The helical axes of the proximal phalanges were located on the dorsal and proximal sides of the hinge, and these tended to move in the volar and proximal directions as the metacarpophalangeal joint flexed.

CONCLUSIONS

Volar and proximal translation of the proximal phalange was observed on 4-dimensional computed tomography.

CLINICAL RELEVANCE

Proximal displacement of the bone axis late in flexion appears to be a contributing factor inducing implant fractures, because the pistoning motion does not allow the implant to move in the proximal direction.

Lower hand grip in rheumatoid arthritis patients is associated with low finite element analysis using high resolution peripheral quantitative computed tomography scan of the 2nd metacarpophalangeal joint

AIM

To evaluate hand function by hand grip test in rheumatoid arthritis (RA) patients, and its association with bone erosions and the estimated bone strength (finite element - FE analysis) through the analysis of the 2nd metacarpal head of the dominant hand using high resolution peripheral quantitative computed tomography (HR-pQCT).

METHOD

Eighty-two female RA patients between 18-50 years old were selected. Demographic data, Health Questionnaire Assessment Disability Index (HAQ), Disease Activity Score of 28 joints (DAS)-28, simplified disease activity index (SDAI) and the hand grip test were set. The HR-pQCT scans of 2nd metacarpophalangeal joints of the dominant hand of all patients were performed according to SPECTRA group protocols. The images were used to assess bone erosions and FE analysis. The hand grip test was categorized in 2 groups and separately compared (< 18 vs ≥18 kgf). A logistic regression was performed using hand grip test <18 kgf as a dependent variable.

RESULTS

A significant difference was found between the 2 groups regarding HAQ, inflammatory markers (erythrocyte sedimentation rate, C-reactive protein), DAS-28, SDAI, total volume of erosion and bone strength parameter (FE analysis - Failure Load [F.Load]). The logistic regression analysis showed that the risk factors associated with hand grip test <18 kgf were higher SDAI (odds ratio [OR] 0.912; 95% CI 0.837-0.993) and lower values of bone strength parameter (F.Load) (OR 1.007; 95% CI 1.002-1.012).

CONCLUSION

Lower values of hand grip test were associated with higher disease activity score-SDAI and lower bone strength of 2nd metacarpal bone head of the dominant hand evaluated here through a FE analysis using HR-pQCT scan.

Functional Instability of the Second to Fifth Metacarpophalangeal Joints

BACKGROUND

Clinically, functional instability (FI) of metacarpophalangeal joints (MCPJ) is not considered to represent a pathology. This excessive mobility can be detected by the application of external forces to a MCPJ at different angles. Our study aimed to measure the FI of 2nd to 5th MCPJ.

MATERIALS AND METHODS

A group of 36 healthy right-handed individuals were enrolled. The value of FI was measured in millimeters and verified by a CT scan. Statistical calculations was made in Statistica v.10.0.

RESULTS

The largest values of the right and left-hand finger posterior displacement (FI) in the second to fifth MCPJ were obtained in the neutral position 0° (p&lt;0.05). Measurements of volar displacement of the proximal phalanx second to fifth MCPJs in both hands revealed higher values at position 0° (p&lt;0.05).

CONCLUSIONS

1. FI of the second to fifth MCPJs is determined by anatomical configuration and dynamic stabilizers. 2. Instability measurements show that posterior displacement of the proximal phalanges is greater by at least 1 mm in the 0° neutral position.

Dorsal Approach in the Surgical Treatment of Complex Dorsal Dislocation of Index Metacarpophalangeal Joint; a Case Report

Complex metacarpophalangeal (MCP) joint dislocation is an uncommon entity, which occurs following a hyperextension injury. Closed reduction is not feasible due to entrapped volar plate and/or coexisting fractures. Various approaches and techniques have been proposed for treatment of complex MCP dislocation; however, controversies exist over which one is superior. This study describes a right-handed 14-year-old boy who fell on the outstretched hand and sustained a dorsal dislocation of the left index MCP joint. The dislocation was complicated by an epiphyseal metacarpal head fracture with dorsal-ulnar displacement of the osteochondral fragment. The patient underwent open reduction through the dorsal approach, and the metacarpal head was fixed via the two-screw technique. The patient resumed left-hand function after six weeks. At the two-year follow-up, the range of motion and grip strength were normal, the patient was pain-free, and no sign of growth disturbance or joint stiffness was detected. Dorsal surgical approach with screw fixation is a feasible technique for the treatment of complex MCP dislocation, especially when it is complicated by a large epiphyseal head fracture.

The "Fight Bite" Saline Joint Loading Test: Effectiveness in Detecting Simulated Traumatic Metacarpophalangeal Arthrotomies

Background: The saline load test is routinely used to recognize other joints' traumatic arthrotomies; however, there are currently no studies evaluating the novelty of this test for metacarpophalangeal joints (MCPJs). This study aimed to investigate the effectiveness and sensitivity of saline load testing in identifying the traumatic arthrotomies of the MCPJs using human cadavers. Methods: This was a cadaveric study of 16 hands (79 MCPJs). Traumatic arthrotomies were created using 11-blade stab-incisions, followed by blunt probing into the joint on the radial or ulnar side of the flexed MCPJs. A 3-mL syringe was used to inject intra-articular methylene-blue-dyed saline from the contralateral side. The volume at saline extravasation was recorded. Test sensitivity and factors influencing extravasation volume were assessed. Results: The mean (range) volume injected to identify arthrotomy of all MCPJs was 0.18 mL (0.1-0.4 mL). The mean volume to identify MCPJ arthrotomy of the thumb, index, long, ring, and small fingers was 0.16 mL (0.1-0.3 mL), 0.19 mL (0.1-0.3 mL), 0.21 mL (0.1-0.4 mL), 0.17 mL (0.1-0.3 mL), and 0.16 mL (0.1-0.3 mL), respectively. Cadaver age, laterality, and joint range of motion were not significantly associated with the injected volume at extravasation(P > .05, each). Injection volumes of 0.3 and 0.32 mL were required to detect arthrotomies at 95% and 99% sensitivities across all MCPJs. None of the MCPJs required > 0.4 mL to detect arthrotomy. Conclusions: Saline joint loading volumes to detect traumatic arthrotomy were similar for all MCPJs. Injection volumes of 0.32 mL is suggested for 99% sensitivity. Our findings provide the first report, to our knowledge, on intra-articular injection volumes expected to detect an arthrotomy of MCPJ. This is critical for further validation using in vivo clinical studies.

Boxer's Knuckle

Teaching Point: Persistent metacarpophalangeal joint pain after clenched-fist trauma with an unremarkable conventional radiography justifies further examination with dynamic ultrasound for detecting extensor hood injuries.

Quantification of morning stiffness to assess disease activity and treatment effects in rheumatoid arthritis

OBJECTIVES

The clinical parameter of morning stiffness is widely used to assess the status of RA, but its accurate quantitative assessment in a clinical setting has not yet been successful. This lack of individual quantification limits both personalized medication and efficacy evaluation in the treatment of RA.

METHODS

We developed a novel technology to assess passive resistance of the MCP III joint (stiffness) and its passive range of motion (PRoM). Within this pilot study, 19 female postmenopausal RA patients and 9 healthy controls were examined in the evening as well as the morning of the following day. To verify the specificity of the biomechanical quantification, 11 patients with RA were assessed both prior to and ∼3 h after glucocorticoid therapy.

RESULTS

While the healthy controls showed only minor changes between afternoon and morning, in RA patients the mean PRoM decreased significantly by 18% (s.d. 22) and stiffness increased significantly by 20% (s.d. 18) in the morning compared with the previous afternoon. We found a significant positive correlation between RA activity and biomechanical measures. Glucocorticoids significantly increased the mean PRoM by 16% (s.d. 11) and reduced the mean stiffness by 23% (s.d. 22).

CONCLUSION

This technology allowed mechanical stiffness to be quantified in MCP joints and demonstrated high sensitivity with respect to disease status as well as medication effect in RA patients. Such non-invasive, low-risk and rapid assessment of biomechanical joint stiffness opens a novel avenue for judging therapy efficacy in patients with RA and potentially also in other non-RA inflammatory joint diseases.

Magnetic resonance imaging of diffusion characteristics following collagenase clostridium histolyticum injection in Dupuytren's contracture

PurposeWe aimed to evaluate the extent of collagenase clostridium histolyticum (CCH) diffusion in Dupuytren's contracture (DC) for tissues outside of the contracture cord using Magnetic Resonance Imaging (MRI) immediately after CCH injection. Methods: 10 male patients aged 57-79 with DC of the metacarpophalangeal (MCP) joints were examined. Extension deficits were 10-60°(mean, 34.3) and 0-60°(mean, 26.6) in the MCP and proximal interphalangeal (PIP) joints, respectively. CCH injection was performed according to the standard method. MRI was performed within 15 min of CCH injection. Results: In all 10 cases, the extended area of high-intensity signal change outside of the cord was observed on short-T1 inversion recovery images (STIRs). Continuity from the insertion site was observed in the area of signal change involving the flexor tendon and neurovascular bundle. The signal change area spanned distally and proximally beyond the injection level. The signal change area expanded along the tendon sheath but no signal changes were observed inside the flexor tendon, suggesting the tendon sheath serves as a protective barrier from the CCH solution. After 1 week of injection, the mean decrease in contracture was 32.5°(94.7%) for the MCP joint and 19.8°(74.4%) for the PIP joint. In nine out of 10 cases, the extension deficit was within five degrees of full extension in the affected finger. There was no neurovascular injury or tendon rupture at 3 months of observation. Conclusions: MRI indicated the possible leakage of the drug outside of the cord during the early phase after administration, suggesting that CCH could persistently affect healthy tissues until CCH inactivates its enzyme process.

Palpation of the lateral bands of the extensor apparatus of the fingers. Anatomy of a neglected clinical finding

This study aimed to determine by ultrasonography, and cadaveric dissection, whether the firm cords felt by palpation at the sides of the proximal phalanx (PP), actively flexing, and extending the proximal interphalangeal (PIP) joint while keeping the metacarpophalangeal (MCP) joint extended are the lateral bands (LBs) of the extensor apparatus. If so, palpation of the LBs could help evaluate hand conditions that impact the digits' intrinsic muscles. To this end, the PP of the middle and ring fingers of the dominant hand of seven subjects were studied by palpation on both sides. Ultrasonography (US) was performed with a hockey-stick transducer placed on the ulnar side. Five cadaveric hands were dissected, exposing the dorsal extensor apparatus. On palpation, a firm cord was consistently felt at the PP's sides in all subjects. These cords moved widely forward on PIP flexion and backward with PIP extension. By US scanning, the cords corresponded to the LBs. However, the forward movement had only a median of 1.8 mm (range 0.7-3 mm) in the middle finger and a median of 1.1 mm (range 0.3-2.7 mm) in the ring finger compared with an estimated 5-10 mm upon palpation. Cadaveric dissection confirmed the forward movement of the LBs in PIP flexion. We concluded that the firm cords felt at the PP sides are the LBs of the extensor apparatus. We confirmed their movement with the active flexion/extension of the PIP joint. Comparing the wide palpatory and the meager US motion, a haptic illusion of motion may be present.

Efficiency of magnetic resonance imaging for diagnosing unstable ligament injuries around the thumb metacarpophalangeal joint: A comparison to arthroscopy

PURPOSE

This study aimed to assess the accuracy of MRI in identifying ulnar collateral ligament (UCL), radial collateral ligament (RCL), and volar plate (VP) injuries of the metacarpophalangeal joint (MCPJ) of the thumb by comparing with diagnostic arthroscopy.

METHODS

A total of 56 consecutive patients (56 thumbs) who underwent arthroscopy of MCPJ of thumb were enrolled. MRI findings reviewed by consensus reading of two blinded radiologists were compared with arthroscopic examination. Statistical data, including sensitivity, specificity, accuracy, were analyzed. Additionally, the performance characteristics between 3.0-tesla (39 thumbs) and 1.5-tesla (17 thumbs) MRI and acute (≤4 weeks after injury) and chronic (>4 weeks) injuries were compared.

RESULTS

Of the 56 thumbs, 38 thumbs (67.9%) showed complete correspondence between MRI and arthroscopic findings. The sensitivity, specificity and accuracy of MRI for detecting UCL injuries were 78.8%, 87.0%, and 82.1%, respectively. The sensitivity, specificity and accuracy of MRI for detecting RCL injuries were 85.7%, 91.4%, and 85.7%, respectively. The sensitivity, specificity, and accuracy of MRI for detecting VP injuries were 89.5%, 89.2%, and 81.0%, respectively. 3.0-tesla MRI showed higher correspondence with arthroscopic observation (76.9%) than 1.5-tesla MRI (47.1%) (p = 0.028). For acute injuries, 78.4% showed complete correspondence between MRI and arthroscopic findings, whereas 47.4% with chronic injuries revealed complete agreement (p = 0.019).

CONCLUSION

Overall, MRI is moderately effective in evaluating ligamentous lesions around MCPJ of thumb, but MRI is more sensitive in diagnosing acute injuries. Furthermore, 3.0-tesla MRI can provide results with better accuracy for diagnosing ligamentous lesions around MCPJ of thumb. However, the sensitivity and the specificity are not applicable to all ligament injuries, but only the severe one which would agree for surgical options.

Neglected volar subluxation of the metacarpophalangeal joint of the thumb: A case report

We present an 30 year-old female patient with a volar subluxation of the metacarpophalangeal joint of the thumb.Dislocation  of the metacarpophalangeal joint is rare ; volar subluxation is much more rare. Open reduction was performed through a dorsal incision because of the soft tissue interposition. Ultimately, doctors in the emergency department should pay attention to volar MCPJ subluxation and it is important to assess collateral ligament stability after closed reduction.

Dynamic External Fixator as Treatment for Congenital Little Finger Contracture

The surgical soft tissue release of extension contracture at metacarpophalangeal (MP) joint is technically easy; however, the preventive hand therapy after surgery is really difficult in clinical practice. Congenital MP joint contracture, especially little finger, is also difficult to spread its limited range of motion (ROM). Here, we present a patient with a congenital MP joint contracture of the little finger managed with dynamic external fixator (DEF). A 21-year-old male irritated from limited ROM associated with pain of the right little finger of more than 1 year. The symptom started after trauma on his hand while playing lacrosse. Further examination revealed that his MP joint was congenitally contracted. To address this pathology, DEF followed by orthotic therapy was done. Two years after the procedure and therapy, the MP joint ROM of the finger surpassed that of the contralateral unaffected digit without pain and recurrence. The patient was able to return to his sports of lacrosse.

Modified Total Intrinsic Rehabilitation Procedure for Ulnar Palsy

Tendon transfer for ulnar palsy has been an area of interest for many a stalwart in hand surgery, especially in southeast Asian countries, mainly because of the prevalence of Hansen’s disease in these countries. Although the procedures look standardized, there are still many lacunae. Here in this article, we discuss about a surgical technique by which all the motor disabilities evolving due to ulnar nerve paralysis are addressed with three sets of tendon transfers performed in a single stage for: (1) key pinch restoration, (2) claw correction and adduction of fingers, and (3) claw correction and abduction of fingers.

Verification of Finger Joint Stiffness Estimation Method With Soft Robotic Actuator

Stroke has been the leading cause of disability due to the induced spasticity in the upper extremity. The constant flexion of spastic fingers following stroke has not been well described. Accurate measurements for joint stiffness help clinicians have a better access to the level of impairment after stroke. Previously, we conducted a method for quantifying the passive finger joint stiffness based on the pressure-angle relationship between the spastic fingers and the soft-elastic composite actuator (SECA). However, it lacks a ground-truth to demonstrate the compatibility between the SECA-facilitated stiffness estimation and standard joint stiffness quantification procedure. In this study, we compare the passive metacarpophalangeal (MCP) joint stiffness measured using the SECA with the results from our designed standalone mechatronics device, which measures the passive metacarpophalangeal joint torque and angle during passive finger rotation. Results obtained from the fitting model that concludes the stiffness characteristic are further compared with the results obtained from SECA-Finger model, as well as the clinical score of Modified Ashworth Scale (MAS) for grading spasticity. These findings suggest the possibility of passive MCP joint stiffness quantification using the soft robotic actuator during the performance of different tasks in hand rehabilitation.

Ultrasound and clinical findings in the metacarpophalangeal joint assessment of show jumping horses in training

Background

Physical exercise is known to cause significant joint changes. Thus, monitoring joint behavior of athletic horses is essential in early disorders recognition, allowing the proper management.

Objectives

The aims of this study were to determine the morphological patterns, physical examination characteristics and ultrasound findings of show jumping horses in training and to establish a score-based examination model for physical and ultrasound follow-ups of metacarpophalangeal joint changes in these animals.

Methods

A total of 52 metacarpophalangeal joints from 26 horses who were initially in the taming stage were evaluated, and the horses' athletic progression was monitored. The horses were evaluated by a physical examination and by B-mode and Doppler-mode ultrasound examinations, starting at time zero (T0), which occurred concomitantly with the beginning of training, and every 3 months thereafter for a follow-up period of 18 months.

Results

The standardized examination model revealed an increase in the maximum joint flexion angles and higher scores on the physical and ultrasound examinations after scoring was performed by predefined assessment tools, especially between 3 and 6 months of evaluation, which was immediately after the horses started more intense training. The lameness score and the ultrasound examination score were slightly higher at the end of the study.

Conclusions

The observed results were probably caused by the implementation of a training regimen and joint adaptation to physical conditioning. The joints most likely undergo a pre-osteoarthritic period due to work overload, which can manifest in a consistent or adaptive manner, as observed during this study. Thus, continuous monitoring of young athlete horses by physical and ultrasound examinations that can be scored is essential.

Reliability and Change in Erosion Measurements by High-resolution Peripheral Quantitative Computed Tomography in a Longitudinal Dataset of Rheumatoid Arthritis Patients

OBJECTIVE

The aim of this multireader exercise was to assess the reliability and change over time of erosion measurements in patients with rheumatoid arthritis (RA) using high-resolution peripheral quantitative computed tomography (HR-pQCT).

METHODS

HR-pQCT scans of 23 patients with RA were assessed at baseline and 12 months. Four experienced readers examined the dorsal, palmar, radial, and ulnar surfaces of the metacarpal head (MH) and phalangeal base (PB) of the second and third digits, blinded to time order. In total, 368 surfaces (23 patients´ 16 surfaces) were evaluated per timepoint to characterize cortical breaks as pathological (erosion) or physiological, and to quantify erosion width and depth. Reliability was evaluated by intraclass correlation coefficients (ICC), percentage agreement, and Light k; change over time was defined by means ± SD of erosion numbers and dimensions.

RESULTS

ICC for the mean measurements of width and depth of the pathological breaks ranged between 0.819-0.883, and 0.771-0.907, respectively. Most physiological cortical breaks were found at the palmar PB, whereas most pathological cortical breaks were located at the radial MH. There was a significant increase in both the numbers and the dimensions of erosions between baseline and follow-up (P = 0.0001 for erosion numbers, width, and depth in axial plane; P = 0.001 for depth in perpendicular plane).

CONCLUSION

This exercise confirmed good reliability of HR-pQCT erosion measurements and their ability to detect change over time.

Assessment of Intra- and Inter-observer Measurement Variability in a Radiographic Metacarpophalangeal Joint Osteophytosis Scoring System for the Horse

The study evaluated the intra- and inter-observer measurement variability of an osteophytosis metacarpophalangeal joint scoring system. Ten (n = 10) dorso/palmar, latero/medial, and oblique views of equine metacarpophalangeal joints affected by osteoarthritis were examined. Nine assessment points were graded (scale: 0–3) twice by five veterinary students (inexperienced group, I) and four equine veterinary surgeons (expert group, E). The grades for each of the nine factors were summed to obtain the osteophytosis score. The variability between the two measurements was −2.04 ± 3.5, 95% CI −3.04 to −1.03 for the I group. For the E group, they were 0 ± 1.43, 95% CI −0.45 to 0.45. In the evaluation of the same radiographs, the I group had a coefficient of variability (CV) of 37.29%. The correlation was r = 0.90%. The CV between groups was 28.85%. The mean difference between the two observations was -0.03 ± 0.29 in the E group and 0.22 ± 0.77 in the I group. The I group showed a greater CV when the score was low (r = −0.78) compared to the E group, where the CV was independent of severity of osteophytosis (r = −0.47). The osteophytosis scoring system is an easily applicable and feasible system to be used by observers with different levels of experience, but inexpert observers may need additional training or may need to be helped by reference images. These data are validated by the low inter- and intra-observer measurement variability results in the E group. Therefore, the scoring system proposed seems to be a repeatable instrument applicable to the radiographic score of the severity of metacarpophalangeal joint osteoarthritis.

Consensus approach for 3D joint space width of metacarpophalangeal joints of rheumatoid arthritis patients using high-resolution peripheral quantitative computed tomography

Background

Joint space assessment for rheumatoid arthritis (RA) by ordinal conventional radiographic scales is susceptible to floor and ceiling effects. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides superior resolution, and may detect earlier changes. The goal of this work was to compare existing 3D methods to calculate joint space width (JSW) metrics in human metacarpophalangeal (MCP) joints with HR-pQCT and reach consensus for future studies. Using the consensus method, we established reproducibility with repositioning as well as feasibility for use in second-generation HR-pQCT scanners.

Methods

Three published JSW methods were compared using datasets from individuals with RA from three research centers. A SPECTRA consensus method was developed to take advantage of strengths of the individual methods. Using the SPECTRA method, reproducibility after repositioning was tested and agreement between scanner generations was also established.

Results

When comparing existing JSW methods, excellent agreement was shown for JSW minimum and mean (ICC 0.987-0.996) but not maximum and volume (ICC 0.000-0.897). Differences were identified as variations in volume definitions and algorithmic differences that generated high sensitivity to boundary conditions. The SPECTRA consensus method reduced this sensitivity, demonstrating good scan-rescan reliability (ICC >0.911) except for minimum JSW (ICC 0.656). There was strong agreement between results from first- and second-generation HR-pQCT (ICC >0.833).

Conclusions

The SPECTRA consensus method combines unique strengths of three independently-developed algorithms and leverages underlying software updates to provide a mature analysis to measure 3D JSW. This method is robust with respect to repositioning and scanner generations, suggesting its suitability for detecting change.

Metabolomic analysis of synovial fluid from Thoroughbred racehorses diagnosed with palmar osteochondral disease using magnetic resonance imaging

BACKGROUND

Palmar osteochondral disease (POD) is a common cause of lameness in competition horses. Magnetic resonance imaging (MRI) is the most sensitive diagnostic modality currently available, however it may not be financially or logistically practical for routine screening of POD. There is increasing interest in the use of metabolomics for diagnosis prior to progression to irreversible damage.

OBJECTIVES

To determine metabolite levels in synovial fluid (SF) of horses with a clinical diagnosis of POD based on diagnostic analgesia and MRI, with the hypothesis that metabolomic profiles differ between diseased and healthy joints.

STUDY DESIGN

Prospective clinical study.

METHODS

Synovial fluid was collected from metacarpo/tarsophalangeal joints (MC/TPJ) of 29 horses (n = 51 joints), including 14 controls (n = 26) and 15 cases (n = 25), the latter with lameness localised to the MC/TPJ and MR changes consistent with POD (n = 23). Spectra were produced using ¹ H-nuclear magnetic resonance (NMR) spectroscopy and analysed.

RESULTS

Twenty-five metabolites were recognised associated with various biosynthetic and degradation pathways. The metabolite abundances within the controls demonstrated increased variability compared with the clinical group. The low level of variance between the spectra of the two groups was explained by five principal components. Cross-validation of the cohort demonstrated modest separation of predictive power (R²  = 0.67; Q²  = 0.34). Although statistical significance was not achieved, the most influential metabolites were glucose and lactate.

MAIN LIMITATIONS

The modest sample size and variation in signalment, background and presenting condition of the controls may have impacted the discriminative power of the constructed models. The lack of matched controls, differences in time of fluid collection and freezing times may have also reduced accuracy when representing metabolite profiles.

CONCLUSIONS

This study identified and quantified metabolites present in MC/TPJ SF of clinical cases with POD.

Ultrasound-guided intra-articular triamcinolone acetonide injection for treating refractory small joints arthritis of rheumatoid arthritis patients

To investigate the efficiency and clinical safety of intra-articular triamcinolone acetonide (TA) injection under the guide of ultrasonography combined with standard treatment for treating refractory small joints arthritis in rheumatoid arthritis (RA) patients.TA was injected upon confirmation of the needle inserting into the articular cavity. The dose was 40 mg for the wrist, 20 mg for the metacarpophalangeal (MCP) joint and 20 mg for the proximal interphalangeal (PIP) joint, respectively. Visual analogue scale (VAS) for joint pain, swelling, tenderness, synovial hyperplasia and power Doppler signal scores were evaluated at pretreatment, and post-treatment 24 hours, 1 week, 4 weeks as well as 12 weeks.The VAS for pain and tenderness scores showed gradual improvement at 24 hours, 1 week, 4 weeks and 12 weeks after treatment compared with the baseline levels (P' < .005). The swelling showed no changes at 24 hours after treatment compared with the baseline, and showed gradual improvement at 1 week, 4 weeks and 12 weeks after treatment (P' < .005). Significant decrease was noticed in the synovial hyperplasia score at 4 weeks and 12 weeks compared with the baseline level. Power Doppler signal score showed significant decrease at post-treatment 24 hours, which showed further decrease at 1 week and 4 weeks.Ultrasound-guided intra-articular TA injection is effective for treating RA patients with refractory small joints arthritis without changing the original treatment plan.

Single-Bundle vs Double-Bundle (Anatomical) Reconstruction of the Thumb Ulnar Collateral Ligament: Biomechanical Study

Background: The goal of this study is to compare the biomechanical properties of anatomic (double-bundle) versus single-bundle reconstruction of the thumb metacarpophalangeal (MCP) joint ulnar collateral ligament (UCL) in a cadaveric model. Methods: Twelve fresh frozen cadaver hands were randomly assigned to single- or double-bundle reconstruction groups using a palmaris longus autograft and tenodesis screws. Two blinded examiners performed mechanical testing and measurements using fluoroscopic imaging. We evaluated MCP joint congruence and angle in the coronal plane at 0°, 30°, and 60° of flexion with valgus loads of 1.36 and 2.72 kg. Maximum MCP flexion and extension with a 0.45 kg load was also measured. Results: There was no significant difference between single- versus double-bundle reconstruction in ulnar congruence or MCP angle. With varying amounts of flexion, there was no significant difference in MCP valgus angle between the 2 techniques, suggesting comparable joint congruity and coronal MCP angle along the arc of thumb MCP motion. Conclusions: Single- and double-bundle UCL reconstructions of the thumb MCP joint have comparable biomechanical properties in regard to joint congruity under valgus load.

The use of equine chondrogenic-induced mesenchymal stem cells as a treatment for osteoarthritis: A randomised, double-blinded, placebo-controlled proof-of-concept study

BACKGROUND

There is a need to improve therapies for osteoarthritis in horses.

OBJECTIVES

To assess the efficacy of equine allogeneic chondrogenic-induced mesenchymal stem cells combined with equine allogeneic plasma as a novel therapy for osteoarthritis in horses.

STUDY DESIGN

Randomised, double-blinded, placebo-controlled experiment.

METHODS

In 12 healthy horses, osteoarthritis was induced in the metacarpophalangeal joint using an osteochondral fragment-groove model. Five weeks after surgery, horses were randomly assigned to either an intra-articular injection with chondrogenic-induced mesenchymal stem cells + equine allogeneic plasma (= intervention) or with 0.9% saline solution (= control). From surgery until the study end, horses underwent a weekly joint and lameness assessment. Synovial fluid was collected for cytology and biomarker analysis before surgery and at Weeks 5, 5 + 1d, 7, 9 and 11. At Week 11, horses were subjected to euthanasia, and the metacarpophalangeal joints were evaluated macroscopically and histologically.

RESULTS

No serious adverse events or suspected adverse drug reactions occurred during the study. A significant improvement in visual and objective lameness was seen with the intervention compared with the control. Synovial fluid displayed a significantly higher viscosity and a significantly lower glycosaminoglycan concentration in the intervention group. Other biomarkers or cytology parameters were not significantly different between the treatment groups. Significantly less wear lines and synovial hyperaemia were present in the intervention group. The amount of cartilage oligomeric matrix protein, collagen type II and glycosaminoglycans were significantly higher in the articular cartilage of the intervention group.

MAIN LIMITATIONS

This study assessed the short-term effect of the intervention on a limited number of horses, using an osteoarthritis model. This study also included multiple statistical tests, increasing the risk of type 1 error.

CONCLUSIONS

Equine allogeneic chondrogenic-induced mesenchymal stem cells combined with equine allogeneic plasma may be a promising treatment for osteoarthritis in horses. The Summary is available in Spanish - see Supporting Information.

Influence of Wrist Position on the Metacarpophalangeal Joint Motion of the Index Through Small Finger

BACKGROUND

The metacarpophalangeal joints exhibit range of motion that is influenced by wrist position. Synergistic motion occurs between the wrist and the metacarpophalangeal joints with different static wrist positions affecting joints' motion capability. The aim of this study was to determine how different wrist positions influence the active range of motion of the index through small finger metacarpophalangeal joints.

METHODS

The active range of motion of the index through small finger metacarpophalangeal joints of 31 healthy subjects was measured in flexion/extension and radial/ulnar deviation in 5 different flexion/extension wrist positions, using biaxial electrogoniometers.

RESULTS

There was a difference in range of motion of all fingers depending on the wrist position. The minimum metacarpophalangeal joint range of motion was found in 80° wrist extension, the maximum in neutral wrist position. For the index finger, flexion/extension was 84.7° (±8.6°) to 25.9° (±10.2°) and radial/ulnar deviation was 32.1° (±11.3°) to 22.6° (±12.8°). For the middle finger, flexion/extension was 84.8° (±8.5°) to 25.9° (±10.1°) and radial/ulnar deviation 28.8° (±11.1°) to 22.1° (±8.9). The fourth finger showed a range of motion for flexion/extension of 87.2° (±11.5°) to 22.8° (±11.6°) and radial/ulnar deviation of 8.1° (±5.8°) to 32.3° (±12.4°). The highest range of motion was measured at the fifth finger with flexion/extension of 84.0° (±8.6°) to 32.1°(±16.8°) and radial/ulnar deviation of 15.1° (±12.9°) up to 54.6° (±18.7°).

CONCLUSIONS

The range of motion of the index through small finger metacarpophalangeal joints was significantly influenced by wrist position. The highest metacarpophalangeal joint range of motion of all fingers was conducted in neutral wrist positions. Apart from ergonomic implications, we conclude that metacarpophalangeal joint motion should be assessed under standardized wrist positions.

Pediatric Complex Metacarpophalangeal Joint Dislocation of the Index Finger

Background

Metacarpophalangeal (MCP) joint dislocations are the result of a hyperextension injury. Complex MCP joint dislocations-those that are irreducible to closed maneuvers and require surgical intervention-are considered uncommon, even in the pediatric population. Although several structures have been identified that contribute to irreducible dislocations, the volar plate is the most significant barrier to reduction through interposition into the MCP joint. Key differences that require consideration for MCP joint dislocations in pediatric patients include ligamentous laxity, the absence of sesamoid bones, the possibility for cartilage fractures, and the possibility of growth arrest. Open surgical intervention for a complex MCP joint dislocation is performed through either the volar or dorsal approach. Controversy exists about which approach is superior.

Case Report

We present the case of a 7-year-old female who sustained a complex MCP joint dislocation of the index finger. After numerous unsuccessful attempts at closed reduction, the patient underwent open reduction through the dorsal approach. The phalangeal head had buttonholed through the volar plate and was reduced by using a Freer elevator as a lever and applying gentle traction and flexion. At 4-week follow-up, the patient was pain-free and had regained nearly full range of motion of the index finger MCP joint.

Conclusion

In addition to the classic volar and dorsal approaches, different techniques have been used to reduce complex dislocations in pediatric patients, including arthroscopic surgery, a percutaneous technique with manipulation of a skin hook, and a percutaneous technique with a dorsal incision. As demonstrated in this case, open reduction through the dorsal approach remains a viable treatment option for complex MCP joint dislocations in the pediatric population.

Ultrasonographic characterization of the ulnar collateral ligament of normal thumbs in different age groups

OBJECTIVES

The aim of this study was to perform ultrasonographic characterization of the normal ulnar collateral ligament in different age groups and compare it in men and women and in dominant and nondominant hands.

METHODS

Forty right-handed volunteers in the age groups 20-30, 31-40, 41-50, and 51-60 years without a history of trauma or surgical procedure in the studied joint were evaluated. The studied parameters were ligament length, greatest ligament thickness, ligament longitudinal section area in the longitudinal plane, distance from the aponeurosis of the adductor muscle to the metacarpal head surface and joint opening at rest and under abduction stress.

RESULTS

The results indicated that the mean values of all parameters had minor variations with age, hand dominance, and gender and were slightly higher in men than in women and in the dominant hand than the nondominant hand. However, a statistically significant difference was observed between the joint opening at rest and under stress. In terms of age, there was a small but nonsignificant decrease in the values, likely because of the natural aging process.

CONCLUSION

The low variability in the evaluated parameters indicates that large differences between sides or genders are not to be expected. A greater change is likely to indicate a pathological situation.

Reconstruction of a metacarpal head defect due to bite injury: two case reports

We present two rare cases of acute osteomyelitis after bite injury that were reconstructed with a third metacarpal base osteoarticular flap and a vascularised medial femoral trochlea osteocartilaginous flap. The outcomes show that a vascularised osteoarticular flap is a good treatment option for a metacarpal head defect.

Intramuscular Tendon of the Adductor Pollicis and Underlying Capsule of the Metacarpophalangeal Joint: An Anatomical Study With Possible Implications for the Stener Lesion

PURPOSE

To identify the layered relationship anatomically between the musculotendinous structures of the adductor pollicis, the ulnar collateral ligament, and the capsule of the metacarpophalangeal joint in terms of understanding the pathomechanism of a Stener lesion.

METHODS

We macroscopically analyzed 37 cadaveric thumbs to identify the intramuscular tendon of the adductor pollicis and bony attachments of the joint capsule including the ulnar collateral ligament. In addition, we histologically analyzed 3 thumbs and made a 3-dimensional image of 3 other thumbs, using micro-computed tomography.

RESULTS

The adductor pollicis has 3 components of an intramuscular tendon (dorsal, palmar, and distal), which connect to form a lambda shape. The dorsal part inserts into the joint capsule dorsal to the ulnar sesamoid. The palmar part inserts into the ulnar sesamoid. The distal part inserts into the lateral tubercle of the proximal phalanx. The thickened and cord-like part of the joint capsule, which has generally been referred to as the proper ulnar collateral ligament, has a distinct bony attachment on the proximal slope of the lateral tubercle of the proximal phalanx separate from the adductor pollicis insertion.

CONCLUSIONS

Of the 3 components of the intramuscular tendon of the adductor pollicis muscle, the dorsal part inserted into not only the aponeurosis but also the joint capsule.

CLINICAL RELEVANCE

The results of the current study suggest the anatomic basis for a possible pathomechanism of the Stener lesion.

Mechanics of Metacarpophalangeal Joint Extension

PURPOSE

It is a common belief that extension of the metacarpophalangeal (MCP) joint of the finger is achieved via the sagittal bands acting as a sling or lasso to attach the extensor tendon to the base of the proximal phalanx. The aim of this study was to test the hypotheses that (1) division of the sagittal bands reduces extension force or torque of the MCP joint, and (2) division of the extensor tendon distal to the sagittal band will not affect the extension force or torque of the MCP joint.

METHODS

Ten cadaver limbs were secured to a jig to allow for testing of the extension force of the MCP joints of the index, middle, and ring fingers. A 1-kg load was applied to the forearm extensor digitorum communis tendon and the extension force was measured with the MCP joint positioned at 0° (neutral extension) and again at 45° flexion. These measurements were repeated after the sagittal bands were divided in 15 specimens; in the other 15 specimens, the extensor tendon was divided just distal to the sagittal bands.

RESULTS

After sagittal band division, extension force was similar in the 2 groups (0.11 N reduction after division with the MCP joints in neutral and 0.14 N in 45° flexion). There was significantly less extension force after division of the extensor tendon in both joint positions (0.95 N reduction after division in neutral extension and 0.66 N in 45° flexion).

CONCLUSIONS

The sagittal bands do not primarily extend the MCP as a sling or lasso. The extensor tendon continuation to the extensor hood and middle phalanx is the major extension motor. The MCP joint is extended by the torque generated by the extensor tendon passing the joint carrying a force and possessing an extension moment arm.

CLINICAL RELEVANCE

This principle should be correctly understood in the literature to ensure that clinical decisions related to injury and/or repair of the extensor tendon and sagittal bands are based on a sound understanding of their mechanics.

Radiographic analysis of the angle in the lateromedial projection of the metacarpophalangeal joint and the distal interphalangeal joint in metacarpophalangeal flexural deformities in calves

The bone alignment of the metacarpophalangeal joint (MPJ) of the distal interphalangeal joint (DIPJ) in metacarpophalangeal flexural deformity (MPFD) in calves was evaluated by radiography. This study was designed by retrospective study of radiographs. Lateral to medial radiographs of distal forelimbs were taken from 19 MPFD affected calves (35 forelimbs) and 21 normal calves (42 forelimbs). Based on the radiographs, the lateral angles of MPJ were measured from the metacarpal bone axis and proximal phalanx axis, and lateral angles of DIPJ were measured from the middle phalanx axis and distal phalanx axis. Mean lateral angle of MPJ in the normal limbs was 175.9 (95% CI 174.5 to 177.4). Mean lateral angles of MPJ in MPFD were as follows: mild: 167.1 (158.9–175.2), moderate: 165.1 (158.5–171.7) and severe: 150.6 (146–155.1). MPJ angle in MPFD limbs was narrower than that in the normal limbs (mild, moderate and severe: P=0.017, P=0.003 and P<0.001, respectively). Mean lateral angle of DIPJ in the normal limbs was 211.9 (210.7–213.2). Mean lateral angles of DIPJ in moderate: 200.6 (195.2–206.1) and severe: 204.9 (203.3–206.5) MPFD were narrower than that in the normal limbs (both P<0.001). There was no significant difference between the normal limbs and mild: 210.3 (206.9–213.7) MPFD limbs (P=0.7). The clinical severity of MPFD corresponded well with the lateral angle of MPJ. The flexion of DIPJ in moderate and severe MPFD was similar to the flexion of MPJ in MPFD. This suggested that the lateral to medial radiographs accurately reflected the MPJ flexion and the DIPJ in MPFD in calves, providing useful information for the treatment of MPFD.

PIGMENTED VILLONODULAR SYNOVITIS IN A RETICULATED GIRAFFE (GIRAFFA CAMELOPARDALIS)

: A 17-yr-old, female, captive-born reticulated giraffe ( Giraffa camelopardalis ) presented with acute-onset lameness of the right metacarpophalangeal (fetlock) joint. Despite multiple courses of treatment, the lameness and swelling progressively worsened over a 3.5-yr period, and the giraffe was euthanized. At necropsy, gross and microscopic changes in the right, front fetlock and associated flexor tendon sheath included villous synovial hyperplasia and the formation of discrete pigmented nodules within synovial membranes. Histologically, the nodules were composed of abundant, fibrous connective tissue with heavy macrophage infiltration, hemosiderin deposition, and distinctive, multinucleated cells that resembled osteoclasts. These findings were consistent with pigmented villonodular synovitis (PVNS), a rare condition affecting both humans and animals. Although the pathophysiology of PVNS is poorly understood, lesions exhibit features of both neoplastic and reactive inflammatory processes. This case report represents, to the authors' knowledge, the first description of PVNS in a nondomestic ungulate.

Propionibacterium Acnes Infection of a Metacarpophalangeal Joint Arthroplasty

Neglected and underestimated in the past, Propionibacterium acnes is currently the most prevalent organism associated with deep prosthetic infections around the shoulder. Surprisingly, it has never been reported as a cause of infection in the hand. Here we report a case of a late presentation of a P. acnes infection in a metacarpophalangeal joint replacement, resulting in chronic low-grade pain with movement. The patient underwent a 2-stage revision, with initial removal of the prosthesis. Positive cultures for P. acnes required 15 days of extended incubation. The patient subsequently had 6 weeks of oral antibiotics followed by a second-stage revision with a Silastic implant.

Clinical Outcome of Metacarpophalangeal Joint Dislocation of the Thumb in Children: Case Series of 10 Patients

OBJECTIVES

Dislocation of the metacarpophalangeal joint of the thumb in children is an uncommon entity. The aim of this study was to evaluate the clinical outcome of pediatric patients with metacarpophalangeal joint dislocation of the thumb.

PATIENTS AND METHODS

Ten pediatric patients with metacarpophalangeal joint dislocation of the thumb were evaluated. Patients were studied prospectively over a period of 3 years. Parameters studied included patient demographics, type of dislocation, management, and any complications.

RESULTS

Mean age of patients was 6.8 years (range: 3-12 years). Seven patients underwent closed reduction and three patients were managed by open reduction. Of the total 10 patients, excellent results were obtained in 9 patients. One of the patients who reported on the fourth day of trauma and was managed by open reduction had mild joint stiffness with a range of motion of 10 to 40 degrees at final follow-up. None of these patients had infection or instability.

CONCLUSION

After thorough clinical and radiological examination, closed reduction can be done in incomplete and simple complete dislocations of metacarpophalangeal joint of the thumb. Repeated closed reduction should be avoided in complex complete injuries. Early mobilization is advised to prevent joint stiffness.

Dorsal Approach Decreases Operative Time for Complex Metacarpophalangeal Dislocations

PURPOSE

Complex metacarpophalangeal (MCP) dislocations require open surgical reduction, but surgeons disagree about the best surgical approach. We hypothesized that a dorsal approach would require less operative time than would a volar approach and result in a decreased need for a secondary approach.

METHODS

We performed a retrospective chart review of all isolated irreducible dorsal MCP dislocations treated at 2 level 1 trauma centers between 2005 and 2015. We recorded the initial surgical approach (volar or dorsal), total operative time, and whether the surgeon used a second surgical approach. Operative times for initial volar approach versus initial dorsal approach, hand surgeon versus non-hand surgeon, and thumb versus other digits were compared using the 2-tailed Student t test. We used Fisher exact test to compare the need for a second approach between the volar and dorsal approach groups.

RESULTS

A total of 21 patients (22 digits) with MCP dislocations required surgical reduction. Average operative time was longer for the 14 patients who underwent the initial volar approach (70 minutes) than for the 7 who underwent an initial dorsal approach (45 minutes). Six of the 14 MCP joints approached volarly (42%) required a second dorsal approach. None of the 7 patients in the dorsal group required a second approach.

CONCLUSIONS

Using a dorsal approach to reduce complex MCP dislocations reduces operative time and decreases the need for a secondary approach.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Correction of Volar Subluxation Deformities of the Metacarpophalangeal Joints Following a Distal Radius Fracture in a Patient With Systemic Lupus Erythematosus

Extensor tendon subluxation over the metacarpal head, leading to metacarpophalangeal joint ulnar deviation, is a hand deformity seen in patients with systemic lupus erythematosus. Apart from soft tissue procedures, metacarpal shortening osteotomy is a previously described surgical treatment for this deformity. We present a patient whose fixed deformity was spontaneously corrected after a displaced distal radius fracture. At 1 year, the correction was maintained. We discuss the biomechanical basis behind the phenomenon.

Comparison of static wrist splint with static wrist and metacarpophalangeal splint in carpal tunnel syndrome

BACKGROUND

The position of metacarpophalangeal (MCP) joints may be an important factor affecting the efficacy of splinting in patients with carpal tunnel syndrome (CTS).

OBJECTIVE

The aim of the present study was to compare the efficacy of a neutral volar static wrist splint with a neutral volar static wrist and MCP splint in patients with CTS.

METHODS

Fifty-four hands were included into the study. A neutral volar static wrist splint was given to the symptomatic hands of the patients in group 1 while a neutral volar static wrist and MCP splint was given to the symptomatic hands of the patients in group 2. Evaluation parameters were Visual Analog Scale for pain severity (VASp), grip strength, pinch strength, electrophysiologic tests and CTS Questionnaire (CTSQ) at baseline and four weeks later.

RESULTS

At baseline there was no difference between groups. The intergroup comparison of the improvement showed significant differences in VASp at rest, grip strength, pinch strength and CTSQ functional capacity scores between groups in favor of wrist MCP splint. Although there were significant improvements with regard to sensory amplitude and motor latency in both groups after therapy, the differences between groups were not at the level of significance.

CONCLUSIONS

The position of MCP joints seems to be an important factor for the treatment of CTS and should be considered while prescribing a splint to the patients with CTS.

Complex Dorsal Metacarpophalangeal Dislocation: Long-Term Follow-Up

PURPOSE

To describe the long-term follow-up results of complex dorsal metacarpophalangeal joint dislocation (MPJD). We hypothesize that there would be no long-term functional deficit in most patients, even with the presence of one of the familiar complications.

METHODS

We describe 5 patients with a median follow-up of 13 (range, 7-36) years and review the literature focusing on follow-up and complications.

RESULTS

All patients reported full function of the hand. Compared with the contralateral finger, a mild loss of MPJ flexion was noted in 2 patients. Grip strength was reduced in 2 patients. The mean QuickDASH score was 4.5 (range, 0-20.5). Two patients with osteochondral metacarpal head fractures treated with screw fixation demonstrated secondary osteoarthritis changes on x-ray. The literature indicates that complications in patients with complex dorsal MPJD are related to failure of diagnosis, multiple attempts at closed reduction, concomitant osteochondral fracture, traumatic open reduction, or prolonged immobilization, and may result in joint stiffness, early degenerative arthritis, or osteonecrosis of the metacarpal head, pain, premature epiphysis closure, and metacarpal shortening.

CONCLUSIONS

The findings from this study suggest that complex dorsal MPJD treated on the day of injury with dorsal or volar open reduction techniques can eventually result in a satisfactory outcome, even with one of the complications mentioned.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic V.

Accuracy and Validity of Goniometer and Visual Assessments of Angular Joint Positions of the Hand and Wrist

PURPOSE

To compare goniometric and visual assessments of angular hand joint and wrist joint positions measured by board-certified hand surgeons and certified hand therapists. We hypothesized that visual estimation would be similar to the goniometric measurement accuracy of digital and wrist joint positions.

METHODS

The wrist, index finger metacarpophalangeal (MCP) joint, and index finger proximal interphalangeal (PIP) joint were evaluated in different positions by 40 observers: 20 board-certified hand surgeons and 20 certified hand therapists. Each observer estimated the position of the wrist, index MCP joint, and index PIP joint of the same volunteer, who was positioned in low-profile orthoses to reproduce predetermined positions. Following visual estimation, the participants measured the same joint positions using a goniometer. The control measurement was digitally determined by a radiologist who obtained radiographs of the hand and wrist positions in each orthosis. Observers were blinded to the results of control measurements.

RESULTS

When considering all joints at all positions, neither visual assessments nor goniometer assessments were consistently within ± 5° of the measurements obtained on control radiographs. When considering individual joints, goniometer measurements were significantly closer to control radiograph measurements than the visual assessments for all 3 PIP joint positions. There was no difference for the measurements at the wrist or for 2 of the 3 MCP joint positions. Significant differences between surgeon and therapist joint angle measurements were not observed when comparing visual and goniometer assessments to radiograph controls.

CONCLUSIONS

Compared with radiograph measurements, neither visual nor goniometer assessment displayed high levels of accuracy. On average, visual assessment of the angular positions of the index MCP and wrist joint were as accurate as the goniometer assessment, whereas goniometer assessment of the angular position of the PIP joint was more accurate than visual assessment. There was a relatively high degree of between-observer variability in measurements, and therefore, no one person's measurements could be consistently relied upon to be accurate.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Comparison of the Thickness of Pulley and Flexor Tendon Between in Neutral and in Flexed Positions of Trigger Finger

Objective:

This study aims to compare the morphology of the A1 pulley and flexor tendons in idiopathic trigger finger of digits other than the thumb between in neutral position and in the position with the interphalangeal joints full flexed and with the metacarpophalangeal (MP) joint 0° extended (hook grip position).

Method:

A total of 48 affected digits and 48 contralateral normal digits from 48 patients who initially diagnosed with idiopathic trigger finger were studied sonographically. Sonographic analysis was focused on the A1 pulley and flexor tendons at the level of the MP joint in the transverse plane. We measured the anterior-posterior thickness of A1 pulley and the sum of the flexor digitorum superficialis and profundus tendons, and also measured the maximum radialulnar width of the flexor tendon in neutral and hook grip positions, respectively. Each measurement was compared between in neutral and in hook grip positions, and also between the affected and contralateral normal digits in each position.

Results:

In all the digits, the anterior-posterior thickness of flexor tendons significantly increased in hook grip position as compared with in neutral position, whereas radial-ulnar width significantly decreased. Both the A1 pulley and flexor tendons were thicker in the affected digits as compared with contralateral normal digits.

Conclusion:

The thickness of flexor tendons was significantly increased anteroposteriorly in hook grip position as compared with in neutral position. In trigger finger, A1 pulley and flexor tendon were thickened, and mismatch between the volume of the flexor tendon sheath and the tendons, especially in anterior-posterior direction, might be a cause of repetitive triggering.