Outcomes of Arthrodesis of the Metacarpophalangeal Joint of the Thumb for Sequelae of Collateral Ligament Injuries: A Series of 18 Cases with 6-Year Follow-Up.

Background: Untreated or insufficiently treated collateral ligament injuries of the thumb metacarpophalangeal (MP) joint can lead to instability or even osteoarthritis. Arthrodesis is one of the treatment options available for the treatment of the sequelae of collateral ligament injuries. The objective of our study was to evaluate the radiological, clinical and functional outcomes of MP joint arthrodesis performed for sequelae of collateral ligament injuries. Methods: We conducted a retrospective, single-centre study and reviewed the files of patients who had a thumb MP joint arthrodesis following a collateral ligament injury between 2011 and 2019. We collected patient's demographic data and the results of the radiological and clinical examinations. Results: Eighteen patients were included in the study. The average age was of 53.6 years and the time between injury to arthrodesis averaged 7 years. Four patients (22%) had nonunion. In the remaining 14 patients with solid union at an average of 72 months follow-up, the visual analogue pain score at rest was 0.14, the thumb opposition was 82%, grip strength 85%, tip pinch 92% and key pinch 79% of the contralateral side. Conclusions: The clinical and functional results of patients with a successful arthrodesis are satisfactory with restoration of good grip and pinch strength. Despite a lack of thumb MP joint flexion, stability allowed force transmission and may be preferred for manual workers. Level of Evidence: Level IV (Therapeutic).

Volar dislocation of the metacarpophalangeal joint of the thumb: open reduction and repair of the ulnar collateral ligament. A case report.

INTRODUCTION: metacarpophalangeal dislocations of the thumb are not very frequent injuries, it is necessary to know the anatomy of the region to know possible causes of interposition that prevent a closed reduction of this pathology. CASE PRESENTATION: we present the case of a 75-year-old woman with a post-traumatic metacarpophalangeal dislocation of the thumb that required open reduction and surgical repair. In this procedure, we performed reduction of the dislocation, mobilization of the interposed structures, repair of the capsule and reinsertion of the ulnar collateral ligament. The early mobilization protocol helped to obtain very good results. CONCLUSION: it is imperative to consider possible associated injuries during the acute phase to achieve optimal short, medium, and long-term outcomes for our patients. A comprehensive and proactive approach to diagnosis and treatment is vital in effectively addressing this pathology and minimizing its potential sequelae.

INTRODUCCIÓN: las luxaciones metacarpofalángicas del pulgar no son lesiones muy frecuentes, es necesario conocer la anatomía de la región para conocer posibles causas de interposición que impidan una reducción cerrada de esta patología. PRESENTACIÓN DEL CASO: presentamos el caso de una mujer de 75 años con luxación metacarpofalángica postraumática del pulgar que requirió reducción abierta y reparación quirúrgica. En este procedimiento realizamos reducción de la luxación, movilización de las estructuras interpuestas, reparación de la cápsula y reinserción del ligamento colateral cubital. El protocolo de movilización temprana ayudó a obtener muy buenos resultados. CONCLUSIÓN: es imperativo considerar posibles lesiones asociadas durante la fase aguda para lograr resultados óptimos a corto, mediano y largo plazo para nuestros pacientes. Un enfoque integral y proactivo del diagnóstico y tratamiento es vital para abordar eficazmente esta patología y minimizar sus posibles secuelas.

Unveiling a foreign body masquerading as periarticular calcification: a case report.

INTRODUCTION: Evaluating isolated extremity discomfort can be challenging when initial imaging and exams provide limited information. Though subtle patient history hints often underlie occult pathologies, benign symptoms are frequently miscategorized as idiopathic. CASE PRESENTATION: We present a case of retained glass obscuring as acute calcific periarthritis on imaging. A 48-year-old White male with vague fifth metacarpophalangeal joint pain had unrevealing exams, but radiographs showed periarticular calcification concerning inflammation. Surgical exploration unexpectedly revealed an encapsulated glass fragment eroding bone. Further history uncovered a forgotten glass laceration decade prior. The foreign body was removed, resolving symptoms. DISCUSSION: This case reveals two imperative diagnostic principles for nonspecific extremity pain: (1) advanced imaging lacks specificity to differentiate inflammatory arthropathies from alternate intra-articular processes such as foreign bodies, and (2) obscure patient history questions unearth causal subtleties that direct accurate diagnosis. Though initial scans suggested acute calcific periarthritis, exhaustive revisiting of the patient's subtle decade-old glass cut proved pivotal in illuminating the underlying driver of symptoms. CONCLUSION: Our findings underscore the critical limitations of imaging and the vital role that meticulous history-taking plays in clarifying ambiguous chronic limb presentations. They spotlight the imperative of probing even distant trauma when symptoms seem disconnected from causative events. This case reinforces the comprehensive evaluation of all subtle patient clues as key in illuminating elusive extremity pain etiologies.

Subclinical joint inflammation in rheumatoid arthritis: comparing thermal and ultrasound imaging at the metacarpophalangeal joint.

BACKGROUND: While ultrasound and MRI are both superior to clinical examination in the detection of joint inflammation, there is presently a lack of data whether thermography may be similarly useful in the assessment of joint inflammation in patients with RA. Our study aims to evaluate the use of thermography in detecting subclinical joint inflammation at clinically quiescent (non-tender and non-swollen) metacarpophalangeal joints (MCPJs) in patients with rheumatoid arthritis (RA). The outcomes from thermography in our study will be compared with ultrasonography (which is a more established imaging tool used for joint inflammation assessment in RA). METHODS: The minimum (Tmin), average (Tavg) and maximum (Tmax) temperatures at the 10 MCPJs of each patient were summed to obtain the Total Tmin, Total Tavg and Total Tmax, respectively. Ultrasound grey-scale (GS) and power Doppler (PD) joint inflammation (scored semi-quantitatively, 0-3) at the 10 MCPJs were summed up to derive the respective TGS and TPD scores per patient. Pearson's correlation and simple linear regression were respectively used to assess correlation and characterize relationships between thermographic parameters (Total Tmin, Total Tavg and Total Tmax) and ultrasound imaging parameters (TGS, TPD and the number of joint(s) with PD ≥ 1 or GS ≥ 2). RESULTS: In this cross-sectional study, 420 clinically non-swollen and non-tender MCPJs from 42 RA patients were examined. All thermographic parameters (Total Tmin, Total Tavg and Total Tmax) correlated significantly (P-values ranging from 0.001 to 0.0012) with TGS score (correlation coefficient ranging from 0.421 to 0.430), TPD score (correlation coefficient ranging from 0.383 to 0.424), and the number of joint(s) with PD ≥ 1 or GS ≥ 2 (correlation coefficient ranging from 0.447 to 0.465). Similarly, simple linear regression demonstrated a statistically significant relationship (P-values ranging from 0.001 to 0.005) between all thermographic parameters (Total Tmin, Total Tavg and Total Tmax) and ultrasound imaging parameters (TPD and TGS). CONCLUSION: For the first time, thermographic temperatures were shown to correlate with ultrasound-detected joint inflammation at clinically quiescent MCPJs. The use of thermography in the detection of subclinical joint inflammation in RA appears promising and warrants further investigation.

Surface wear of PyroCarbon implant in metacarpophalangeal joint arthroplasty without radiographic abnormality: A case report.

CASE: A 54-year-old male with osteoarthritis of the right long finger metacarpophalangeal joint underwent PyroCarbon joint arthroplasty. Seven years later the patient presented for metacarpophalangeal joint swelling and pain. The workup was benign, without signs of implant complication or osseous abnormality. He underwent washout and two-stage revision, where gross implant wear and debris not demonstrated by radiograph were found. He then returned to the operating room for reimplantation of a PyroCarbon implant. CONCLUSION: This case demonstrates a novel presentation of aseptic PyroCarbon implant failure in the hand without radiographic abnormality that can alter operative management by reducing operating room returns.

Novel figure-of-eight reconstruction with free tendon graft for unrepairable collateral ligament of the thumb metacarpophalangeal joint.

OBJECTIVES: This study aimed to report surgical technique and clinical outcomes for a novel figure-of-eight collateral ligament reconstruction technique using palmaris longus autograft for chronic irreparable collateral ligament injury of the thumb metacarpophalangeal joint. MATERIAL AND METHODS: The Jobe elbow collateral ligament reconstruction method was adapted for thumb metacarpophalangeal joint collateral ligament reconstruction. Sixteen reconstructions (7 ulnar collateral ligament, 9 radial collateral ligament) using palmaris longus autograft were reviewed retrospectively. Surgery was performed at a mean 12 months post-injury. All 16 patients were followed up for more than 1 year. Metacarpophalangeal joint radial and ulnar deviation, metacarpophalangeal and interphalangeal joint range of motion, key pinch and grip strength, Glickel functional grade and QuickDASH score were evaluated. RESULTS: Preoperative radial or ulnar deviation improved from 19.3° to 5.3° postoperatively. Metacarpophalangeal range of motion improved from 31.5° to 46.6°, and interphalangeal range of motion from 48.4° to 65.6°. Preoperative key pinch and grip strength were respectively 49% and 81% of contralateral values and improved to 82% and 87%. On Glickel grade, 9 cases were excellent and 7 good. CONCLUSION: The novel Jobe-like figure-of-eight reconstruction technique using palmaris longus graft was useful for reconstructing irreparable thumb metacarpophalangeal joint instability without an incision on the opposite side or an additional implant. LEVEL OF EVIDENCE: Therapeutic study, level IV.

The Effects of Boxing Glove Design on Thumb Position When Making a Fist for Striking.

ABSTRACT: Peveler, WW, Schoffstall, J, Coots, J, Kilian, J, and Glauser, J. The effects of boxing glove design on thumb position when making a fist for striking. J Strength Cond Res 38(5): 948-950, 2024-It has been suggested that boxing glove design alters thumb position increasing the risk of injury. The purpose of this study was to determine the effects of boxing glove design on thumb joint angles when making a fist. Ten experienced fighters participated in this study. A DEXA scan was used to produce an x-ray image of thumb position for all conditions (no gloves and 10-oz boxing gloves). Mean values for dependent measures were compared using a paired-sample T test and an alpha of 0.05. The carpometacarpal (CMC) joint angle was significantly different between no glove (14.1 ± 6.54°) and boxing glove (34.2 ± 7.60°) at p ≤ 0.001. The metacarpophalangeal (MP) joint angle was significantly different between no glove (132.6 ± 12.74°) and boxing glove (149.40 ± 8.15°) at p ≤ 0.001. The IP joint angle was not significantly different between no glove (135.50 ± 19.12°) and boxing glove (144.40 ± 17.39°) at p = 0.269. The perpendicular distance from the second metacarpal of the hand to the center of the MP joint was significantly different between no glove (0.48 ± 0.54 cm) and boxing glove (1.84 ± 0.29 cm) at p ≤ 0.001. Use of a boxing glove resulted in abduction of the thumb away from the hand and increased CMC and MP joint angles that were significantly different in relation to making a fist without a glove. Information from this study may provide insight into the high rate of thumb injury and provide insight for future boxing glove design.

How Does Ultrasound Global OMERACT-EULAR Synovitis Score (GLOESS) for Rheumatoid Arthritis (RA) Activity Assessment Perform in Real-Life?

OBJECTIVE: This study aimed to assess the effectiveness of the Global OMERACT-EULAR Synovitis Score (GLOESS) of bilateral second to fifth metacarpophalangeal joints (MCP 2-5) in evaluating rheumatoid arthritis (RA) activity in a real-life setting. METHODS: This cross-sectional study included consecutive RA patients without hyperalgesia. Clinical data were extracted from electronic medical records. Evaluations were conducted on bilateral MCP 2-5 by two independent experts in musculoskeletal ultrasound (MSUS). Correlation between clinical and ultrasonographic parameters was analyzed, aiming to define a cutoff value for detecting disease activity. RESULTS: Sixty-nine patients were included. The mean DAS28-ESR was 4.3 (±1.4), and the median GLOESS was 7 (13). The correlation between GLOESS and DAS28 was moderate (r = .62; P < .05). A total GLOESS score of ≤3 and all joints with both GS and PD ≤1 showed good sensitivity and specificity for detecting disease activity (remission/low vs moderate/high, P = 0). CONCLUSION: In a real-life scenario, GLOESS for MCP 2-5 emerges as a valuable measure of RA activity. The optimal cutoff distinguishing remission/low from moderate/high disease activity was determined to be GLOESS ≤3, with all MCP joints exhibiting both GS and PD scores of ≤1.

Metacarpophalangeal joint reconstruction using a costal osteochondral graft: A case report.

RATIONALE: The conventional treatment of giant cell tumors is intralesional curettage with local adjuvant therapy. Because hand tumors have a high local recurrence, the primary goal for treating tumors of the hand is to eradicate the lesion. PATIENT CONCERNS: To preserve the metacarpophalangeal (MCP) joint function as well as avoid further recurrence after surgery. DIAGNOSES: The giant cell tumor invades the patient's MCP joint in an index proximal phalanx. INTERVENTIONS: Using computer-aided design and three-dimensional printing techniques, we reformed the original shapes of the MCP joint and its peripheral bone to replica models. The surgeon then performed an en bloc resection and proximal phalanx with MCP joint reconstruction by fabricating the patient's costal osteochondral graft during the operation. OUTCOMES: After 6 months of rehabilitation, the patient's finger functions could pinch and grasp objects naturally. At the 1-year follow-up, the range of motion of the MCP, proximal interphalangeal, and distal interphalangeal joints improved from flexion of 35° to 60°, 75° to 85°, and 60° to 80°, respectively. The hand function achieved the mean performance of non-preferred hands for young females at the postoperative 3-year follow-up. LESSONS: The customized prototyping technique has the potential to replica the original patient's bony graft to reach the goal of minimizing the defects at the donor site and maximizing the function of the reconstructed MCP joint.

Biological Versus Nonbiological Reconstruction of the Ulnar Collateral Ligament of the Thumb Metacarpophalangeal Joint: A Retrospective Study.

PURPOSE: The purpose of this study was to compare clinical and radiologic outcomes of biological ligament reconstruction (BLR) versus nonbiological ligament reconstruction (NBLR) for chronic injuries involving the ulnar collateral ligament of the thumb's metacarpophalangeal joint. METHODS: Forty-two patients who underwent static BLR (n = 24) or NBLR (n = 18) were included in this retrospective analysis. Preoperative, postoperative, and contralateral thumb measurements (clinical evaluation, radiographs, and subjective outcome questionnaires) were compared over a mean of 38 months of follow-up. RESULTS: Average postoperative thumb metacarpophalangeal and interphalangeal joint ranges of motion were 2° to 54° and 0 to 71°, respectively, for BLR and 0° to 58° and 0° to 71°, respectively, for NBLR. Average grip and pinch strengths, relative to the unaffected hand, were 102% and 84% versus 103% and 89%, respectively. All patients demonstrated stability with a firm end point, compared with the unaffected thumb. The average Quick Disabilities of the Arm, Shoulder, and Hand score among all patients was 12 for the disability/symptom module, 0 for the sports module, and 17 for the work module. Stiffness was reported among four patients, and no patient sustained wound-related issues or other complications. CONCLUSIONS: Nonbiological ligament reconstruction of the thumb ulnar collateral ligament generates short-term outcomes comparable with those of BLR, potentially allowing for expedited recovery and rehabilitation. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

The mechanics of the collateral ligaments in the metacarpophalangeal joints: A scoping review.

BACKGROUND: The metacarpophalangeal (MCP) joint's collateral ligaments have been extensively debated, with no clear consensus on their mechanics. Understanding their function is crucial for comprehending joint movement and stability. METHODS: A thorough search was conducted across databases, including PubMed, Scopus, Cochrane library and grey literature. A total of 59 articles were identified, and after rigorous evaluation, six articles were included in the review. RESULTS: The analysis underscores two principal findings. Firstly, the principal and accessory collateral ligaments exhibit consistent tension influenced by the MCP joint's position. This tension varies across different sections of the ligaments. Secondly, the ligaments' interaction with the joint structure plays a pivotal role in defining the range of motion of the joint. CONCLUSION: Preliminary findings from this review indicate that MCP joint collateral ligament tension varies with joint position. Increased tension in the principal collateral ligament during flexion and isometric behavior of its volar portion in extension are observed. The accessory ligament may tighten during extension. The shape of the metacarpal head appears to influence this tension. These insights, while informative, call for further detailed research to deepen our understanding of MCP joint mechanics.

Kinematic Investigation of Healthy, Arthritic, and Postsurgery Thumbs: Is the Metacarpophalangeal Joint the Gateway to Carpometacarpal Arthritis?

The thumb carpometacarpal (CMC) joint is one of the most likely joints to develop osteoarthritis (OA). If conservative treatments fail to alleviate symptoms, surgery may be pursued. Kinematic outcomes of CMC surgery techniques have been described, but current tools have limitations in capturing motion abilities. The goals of this study were (1) develop a new and robust set of kinematic outcome measures, and apply them to (2) a cohort of younger and older control individuals without CMC OA to determine age and sex-related changes, and (3) a cohort of participants with CMC OA before, 3 months, and 6 months after undergoing thumb ligament reconstruction with tendon interposition surgery to detect the impacts of surgery. 52 (26 males, 26 females) control and 18 (3 males, 15 females) surgical participants were tested. Kinematics were investigated using motion capture by mapping the three-dimensional motion space of the whole thumb, and two-dimensional motion boundaries of the metacarpal (MC) and proximal phalange (PP). Visual analog pain score was recorded. Older control participants had shifted regions of motion compared to younger participants (p ≤ 0.027), suggesting asymptomatic CMC wear. Control females had 31% more metacarpophalangeal (MCP) motion than control males (p = 0.013), which could alter loading paths through the CMC joint and increase OA risk. Pain at 6 months postsurgery was 72% less than presurgery (p < 0.001), but motion abilities were 20-28% less than presurgery (p ≤ 0.074) and 24-40% less than control participants (p ≤ 0.066). These techniques have the possibility of identifying presymptomatic motion changes, including those at the metacarpophalangeal joint in CMC OA progression.

Long-Term Implant Fracture Rates Following Silicone Metacarpophalangeal Joint Arthroplasty in Rheumatoid Arthritis.

PURPOSE: The primary objective of this study was to compare the long-term survival rates of silicone metacarpophalangeal (MCP) arthroplasties between two major implants in patients with rheumatoid arthritis, using implant fracture as an end point. We also evaluated the difference in postoperative function between patients with fractured and intact implants as a secondary objective. METHODS: A retrospective cohort study was conducted on 372 fingers of 133 hands that underwent silicone MCP arthroplasty between January 2000 and June 2019 (mean follow-up, 7.6 years). The survival rates of Swanson-type and Sutter-type implants were compared, using implant fracture as the end point after a radiographic evaluation. Clinical measures and upper limb functional assessments using the Disabilities of the Arm, Shoulder, and Hand (DASH) score were performed in the nested cohort. RESULTS: The 10.6-year survival rates for implant fracture of Swanson- and Sutter-type implants were 86.2% and 9.4%, respectively, with significantly higher survival noted for Swanson-type implants. The Sutter-type implant showed increased susceptibility to fracture in all four fingers compared to the Swanson-type implant. Implant fractures were primarily observed at the stem-hinge junction. There were no significant differences in upper limb function between the fractured and intact implant groups. CONCLUSIONS: Sutter-type implants were found to be more prone to fracture compared with Swanson-type implants. However, implant fractures did not significantly affect upper limb function. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognosis IV.

High Fracture Rate of AVANTA Silicone Implant Following Arthroplasty of the Thumb MCP Joint of Rheumatoid Arthritis Patients with Boutonniere Deformities.

We retrospectively investigated the mid-term outcomes of arthroplasty using the AVANTA silicone implant for thumb metacarpophalangeal (MCP) joints with boutonniere deformity in patients with rheumatoid arthritis (RA). This study involved 36 thumbs of 33 RA patients with a mean follow-up period of 5.1 years (range, 2.0-13.3). Postoperatively, the mean extension was significantly increased and the mean flexion was significantly decreased (p<0.001, p<0.001, respectively), resulting in the mean arc of range of motion (ROM) shifting in the direction of extension after surgery. Implant fracture was observed in 10 thumbs (28%), and 4 of these (11%) underwent revision surgery. The survivorship with implant fracture and revision surgery as endpoints were 73.4% and 91.8% at 5 years, respectively. The preoperative arc of ROM and the postoperative flexion range of the implant-fracture group were significantly greater than those in the no-implant-fracture group (p=0.039, 0.034, respectively). These results suggest the importance of patient education and careful rehabilitation to prevent excessive flexion. Overall, the AVANTA silicone implant showed a relatively high rate of implant fracture at our institute.

The Application of Sesamoid Position in Diagnosing Thumb Metacarpophalangeal Joint Dorsal Dislocation: A Retrospective Study.

OBJECTIVES: The position of sesamoid of thumb metacarpophalangeal (MCP) joint changed clearly when the joint was dislocated dorsally. However, the significance of sesamoid location in diagnosing joint dislocation was unclear. The present study aimed to explore the positional relationship between sesamoid bone and thumb metacarpophalangeal joint in normal and dorsal dislocation joints. METHODS: Between January 2018 and August 2023, we collected 60 isometric plain films from sixty outpatients and reviewed 56 anisometric plain films from twenty-eight emergency patients with dorsal dislocation of thumb MCP joint at Tianjin Hospital, then took measurements on the hand X-ray images. The sesamoid length on its longitudinal axis was defined as DP, the distance between the distal edge of sesamoid and thumb MCP joint was defined as DJ, and the ratio of DJ and DP was R. An independent-samples t-test and paired-samples t-test was utilized to analyze difference among data groups. RESULTS: The 60 isometric images were from 30 male and 30 female outpatients with normal bone structure in their hands, and the 56 anisometric images of the 28 emergency patients included both preoperative and postoperative materials. Among the outpatients, the actual distance between the distal edge of sesamoid and thumb MCP joint space (DJ) was 2.09 mm and 1.40 mm in males and females, respectively. The authentic average length of sesamoid (DP) was 4.46 mm in males and 4.22 mm in females. The average value of R (the ratio of DJ and DP) in males and females was 0.49 and 0.34, respectively. There were gender-related statistical differences in DJ (p < 0.01) and R (p=0.01), but no statistical difference in DP (p > 0.05). For the 28 emergency patients, the mean value of R was -0.47 before joint reduction and 0.58 after joint reduction, with statistical difference between them (p < 0.01). CONCLUSIONS: There was significant difference in the relative position between sesamoid and thumb MCP joint when joint dislocation and joint reduction. The distal edge of sesamoid beyond thumb MCP joint could be an evidence in diagnosing joint dorsal dislocation. The distal edge of sesamoid below thumb MCP joint could be an evidence of joint reduction.

Multiple pilonidal sinuses of both hands in a dog groomer: A case report.

OBJECTIVE: Pilonidal sinus of the hand is an occupational hazard for barbers, cow milkers, sheep shearers and dog groomers. Here, we report on a dog groomer who had four pilonidal sinuses. CASE PRESENTATION: A 49-year-old woman working as a dog groomer complained of multiple non-erythematous and fluctuant nodules on both hands, associated with pain, which had been identified five years previously. On the skin of her right hand, three nodules were observed on the volar (diameter: 1.5 cm) and medial (diameter: 1.4 cm) sides of fifth metacarpophalangeal joint and the volar aspect of the distal phalanx of the small finger (diameter: 0.7 cm). On the left hand, a 2-cm diameter nodule was identified on the volar side of the fifth metacarpophalangeal joint region. The nodules were excised surgically. A 5-mm long hair was removed from one nodule. Histopathology confirmed pilonidal sinus, treated by excision. One month postoperatively, the wound had healed uneventfully. CONCLUSION: When nodules are found in dog groomers, clinicians should consider the possibility of pilonidal sinus disease.

Contribution to the study of stresses in the thumb column during key pinch grip.

OBJECTIVES: The aim of this study was to calculate the stress acting on the trapeziometacarpal joint during an key pinch grip. METHOD: We used profile X-rays of the thumb to measure the various bony and muscle lever arms. We assessed the angles of action of the muscular elements involved in the thumb column. Based on this data, we established a two-dimensional geometric model that enabled us to determine the forces at each joint level, as a function of stresses and muscular contributions. We were also able to calculate the participation of the different muscle groups in obtaining a balanced situation. RESULTS: Our results, as a function of the degree of flexion of the interphalangeal and metacarpophalangeal joints, show a multiplying factor of 2.9-3.19 in relation to the key pinch grip force. DISCUSSION: Previous studies modelling a key pinch grip are showed multiplying factors from 6 to 13 in relation to the key pinch grip force. They are not compatible with the characteristics of the polyethylene used for trapeziometacarpal prostheses, whereas numerous articles in the literature show survival rates that are more or less comparable to those of total hip prostheses. These studies required an excessive number of assumptions, which could lead to error. Our results are compatible with the results of trapeziometacarpal prosthesis and with those of a recent study measuring intra-articular trapeziometacarpal pressure in a cadaveric model. Our model allows us to test different configurations of the thumb spine depending on the degree of flexion of the interphalangeal and metacarpophalangeal joints.

Locking of the metacarpophalangeal joint: A comprehensive review of the literature.

Locked metacarpophalangeal joint is an uncommon phenomenon with many possible etiologies. Diagnosis can be difficult because of the many more common pathologies (trigger finger, sagittal band lesion, etc.) that can lead to a clinical picture that may resemble the locked metacarpophalangeal joint. Once the differential diagnoses have been eliminated, the etiology of this blockage must be determined and the surgical procedure must be oriented. The origin of the problem is often difficult to determine, especially since standard imaging tests are often not very informative. Several clinical forms are possible, with blockages in extension or flexion, but which will have a disabling functional impact on the overall function of the hand. Currently, there is no gold standard for the management of this condition. In this study, we performed a review of the literature in order to better understand the different possible etiologies but also to analyze the different diagnostic and therapeutic management. LEVEL OF EVIDENCE: IV.

Thumb Metacarpophalangeal Joint Kinematics and Elongation of the Ulnar Collateral Ligament.

PURPOSE: The purpose of the study was to determine if the sphericity of the thumb metacarpophalangeal (MCP) joint influences the joint's rotational axis (RA) and elongation patterns of the ulnar collateral ligament (UCL). METHODS: Ulnar collateral ligament origins and attachments of 28 fresh-frozen cadaveric thumbs were marked with a radiopaque marker. Lateral radiographs were obtained in neutral and 20°, 40°, and 60° of flexion. The dorsal and palmar joint gap and the length of four different UCL portions were digitally measured in all flexion states. The RA was determined by the intersection of the midshaft axis of the proximal phalanx in neutral and flexion states. Sphericity of the MCP joint was assessed using morphometric parameters. Joints were grouped as round or flat. Differences in all measured parameters between groups were analyzed. RESULTS: During flexion, the dorsal joint gap increased by 322% in flat joints and 163% in round joints. The palmar joint gap decreased to 45% in flat joints and to 87% in round joints. The RA was at 29% of metacarpal height and 96% of metacarpal length in flat joints and at 40% of height and 86% of length in round joints. Maximum UCL elongation (111%) was noted at 40° flexion in the dorsal proper UCL in flat joints and at 60° flexion in the accessory UCL (117%) in round joints. CONCLUSIONS: In flat MCP joints, the RA is more dorsal and distal in the metacarpal head compared to round joints, resulting in a hinged flexion motion. Elongation of the UCL is highest at end flexion in round joints and highest at midflexion in flat joints. CLINICAL RELEVANCE: The different kinematics of flat and round MCP joints may contribute to the understanding of the pathophysiology of UCL ruptures. The propensity of this injury and the position in which they occur may be affected by the MCP joint morphology.

The influence of a tension band fixation as an adjunct for arthrodesis of the metacarpophalangeal joint in the horse.

OBJECTIVES: To determine the influence of a stainless-steel cable (SSC) tension band fixation as an adjunct to a locking compression plate (LCP) for arthrodesis of the equine metacarpophalangeal (MCP) joint. STUDY DESIGN: Experimental. An ex vivo biomechanical paired equine cadaver limb study. SAMPLE POPULATION: Five MCP joint pairs were collected from adult Thoroughbred horses, euthanized for reasons unrelated to orthopedic disease. METHODS: Each pair of MCP joints were randomly implanted with either a dorsally placed 5.5 mm LCP and a palmarly placed 2.0 mm SSC or a dorsally placed 5.5 mm LCP alone. Each construct was tested in cyclic loading followed by single cycle to failure in axial compression. Displacement at a target load of 1 kN over 3600 cycles at 1 Hz was recorded prior to single cycle to failure testing. RESULTS: In cyclic testing, displacement was not significantly different between the first and last 5% of testing cycles regardless of construct. Maximum displacement of each construct during cyclic testing was <1.1 mm. In single cycle testing, the observed yield point did not reveal any difference between LCP and LCP-SSC (p = .440). The maximum load at failure was significantly higher in LCP-SSC compared to constructs with the LCP alone (p = .046). CONCLUSION: The addition of the SSC to the LCP did not statistically affect construct displacement during cyclic loading or construct yield load during subsequent single cycle to failure. CLINICAL SIGNIFICANCE: This study provided much needed information regarding the necessity of a tension band SSC application in the arthrodesis of the MCP/MTP joint in horses.