UNASSIGNED: The intramedullary interlocking device for metacarpophalangeal (MCP) joint arthrodesis (XMCP, Extremity Medical, Parsippany, NJ) has been shown to promote union at a precise angle, provide strong fixation without the need for prolonged immobilization, and lower the incidence of hardware irritation and revision surgery. In this study, we evaluated the clinical outcomes of patients undergoing MCP joint arthrodesis with the XMCP system using a retrospective chart review, patient reported outcomes, and radiographic analysis.
UNASSIGNED: A retrospective chart review and phone survey was conducted on 57 patients (58 cases) from a single institution between 2017 and 2022. The primary outcome was patient satisfaction, including pre- and postoperative Numeric Rating Scale (NRS) pain scores, Disabilities of Arm Shoulder and Hand (QuickDASH) outcomes, perceived grip strength, and willingness to undergo the procedure again. Secondary outcomes included the need for revision procedures, successful fusion of arthrodesis, and postoperative complications.
UNASSIGNED: Of the 57 patients who underwent MCP joint arthrodesis of the thumb using the XMCP fusion device, a total of 43 (75%) completed the phone survey. The average age of patients was 67 years with an average clinical follow-up of 9 months (range 1-65 months). Patients who participated in the phone survey questionnaire had an average QuickDASH score of 24.7 ± 20.5. Average perceived NRS scores were 6.2 ± 3.5 and 1.2 ± 2.1 before and after surgery, respectively. Average perceived grip strength of patients was 3 ± 1.3 out of 5. When evaluating for concurrent procedures, there was no statistically significant difference in pre- or postoperative NRS scores. In total, 38 (88%) patients were satisfied with the procedure, and 39 (91%) patients would undergo the procedure again.
UNASSIGNED: Metacarpophalangeal joint arthrodesis of the thumb with the intramedullary fusion device is reproducible, allows for immediate use without immobilization, has a low number of complications, and provides improved function and pain relief.
UNASSIGNED: Therapeutic III.

Herein we present a case of four simultaneous dislocations of the hand resulting from a motorcycle accident in a young man. In this case, the 1st CMC, MCP, and IP joints of the right hand were dislocated along with right perilunate dislocation. Perilunate dislocation was treated with open reduction and internal fixation. Close reduction of IP and CMC was done and CMC was fixed by pins. MCP dislocation was treated by open reduction and pinning in addition to collateral ligament and capsular repair. In follow-up excellent functional activity and range of motion were observed.

For manipulation, this paper addresses arguably the most fundamental question that can be asked about any therapeutic intervention: what is it? In answering this question, this paper presents the prevailing model of joint manipulation (of Sandoz) and explains why this influential model is fundamentally flawed. The early research on \'joint cracking\' that led to the development of this model is described in chronological order, alongside how this research was misinterpreted, which gave rise to the model\'s flaw. Of concern, the flaw in this model makes worrying predictions that could lead to dangerous clinical decisions. Understandably, these predictions have attracted criticism over the use of manipulation as a therapeutic intervention. A corrected model, first published by Evans and Breen more than 15 years ago, is then presented and explained. Unlike the flawed model, this corrected model makes predictions in line with all available empirical data and additionally provides reassuring answers to critics. Many current definitions of manipulation have inherited the flaw from Sandoz\'s model. Hence, a better, empirically derived definition, consistent with the corrected model, is now required.

UNASSIGNED: Juvenile idiopathic arthritis (JIA) is an inflammatory arthritis of childhood that can lead to pain and dysfunction of the hands. In severe progressive cases, in which medical treatment does not result in symptom improvement, limited options are available. Metacarpophalangeal (MCP) joint arthroplasty remains a standard surgical treatment for inflammatory arthritis of the MCPmetacarpophalangeal joints in adults; however, no reports exist about its use in children or for JIA.
UNASSIGNED: We present two cases of MCP joint arthroplasty in patients with severe progressive JIA. The first patient presented at 21 years old with increasing pain and limited use of her right hand and underwent MCP arthroplasty using a pyrocarbon implant. The second patient presented at 14 years old with severe pain, contractures, subluxations, and the inability to use her right hand, subsequently undergoing MCP replacement with a silicone-based implant. The joint replacements resulted in pain relief and improvement of hand function for both patients, though the pyrocarbon implants had poor radiographic outcomes at 7 years follow- up, while the silicone implants had limited functional improvement.
UNASSIGNED: MCPMetacarpophalangeal joint replacement may be considered in patients with severe inflammatory arthritis to relieve pain and/or to extend functional use of the fingers and hands. In these cases, silicone arthroplasty radiographically fared better than pyrocarbon.

The metacarpophalangeal (MCP) joint is surrounded by various structures critical to its stability and function. Though the ligamentous injury to the digits is common, rupture of the metacarpophalangeal collateral ligament and a sagittal band of the same finger is not well represented in the literature. We report a chronic case of a concurrent metacarpophalangeal collateral ligament and sagittal band injury. Though surgery would have been the most appropriate treatment soon after the injury, restrictions on elective procedures due to the COVID-19 pandemic precluded surgical treatment. The patient was alternatively treated with buddy tape, and a close follow-up was done. This is the first reported case of a concurrent metacarpophalangeal collateral ligament, and sagittal band injury successfully treated using nonoperative management.

MRI-detected inflammation around the extensor tendons of metacarpophalangeal (MCP-) joints is prevalent in RA and poses a markedly increased risk of RA development when present in arthralgia patients. Such inflammation is called \'peritendinitis\' since anatomy literature reports no presence of a tenosynovial sheath at these tendons. However, the presence or absence of tenosynovium at these extensor tendons has never been studied. Therefore, an anatomical and histological study of extensor tendons at the MCP-joints of three embalmed human hands was performed. Immunohistochemical staining showed the presence of markers for synovial macrophages and fibroblast-like synoviocytes bordering a natural dorsal space next to the extensor tendon, suggesting the presence of a synovial lining. This implies that contrast-enhancement on MRI around extensor tendons at MCP-joints observed in early RA and pre-RA likely represents tenosynovitis and that inflammation of this synovial tissue is an early feature of RA.

BACKGROUND: The innervation of the digital joints as well as the anatomical relationships of the articular branches is present in this anatomical work to determine the technical feasibility of a selective and efficient denervation of the digital joints.
METHODS: A study of 40 distal interphalangeal (DIP), 40 proximal interphalangeal (PIP), 50 metacarpophalangeal (MCP), 10 interphalangeal (IP) of the thumb, and 10 trapezo-metacarpophalangeal (TMC) joints was performed on ten hands. Under magnification and a proper surgical approach, we collected the course, the source origin, the number of articular nerve branches, and their caliber.
RESULTS: In total, 118 nerve branches arising from the proper palmar digital nerves were found on 10 DIP of each dissected long finger (n = 40). A total of 226 nerve branches were found on 10 PIPs of each long finger (n = 40), of which 204 branches (90.3%) had a palmar origin. Dorsal innervation was found for the ring and little finger, originating from the dorso-ulnar digital nerve. 212 branches were found on 10 MCP of long fingers (n = 40), including 87 branches of palmar origin (41.1%), 107 branches of dorsal origin (50.4%), and 18 branches of the motor branch of the ulnar nerve (8.5%). 42 articular branches directed to the TMC joint (n = 10) were found. 13 branches (31%) originated from the anterior sensory branch of the radial nerve, 13 branches (31%) originated from the lateral cutaneous nerve of the forearm, 5 branches (12%) originated from the palmar cutaneous branch of the median nerve, and 11 (26%) branches originated from the thenar branch of the median nerve. The involvement of the sensory anterior branch of the radial nerve was always present for the innervation of each TMC.
CONCLUSIONS: Our research shows that finger joints receive their primary innervation from small branches of the digital nerves with the exception of the MCP joint and the TMC joint. To obtain an efficient and a selective digital denervation for articular pain relief, it is necessary to plan the best surgical approach and it is crucial to recognize the articular nervous branch localization and source.

The moment arm of a muscle\'s force represents the muscle\'s leverage or mechanical advantage in producing a joint moment. It is indicative of the muscle\'s potential to contribute to actuation of a joint in a particular joint motion direction and defines the role of the muscle, for example, as a joint flexor or abductor. The aims of this study were, firstly, to measure the moment arms of the flexor and extensor muscles of the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints, and the moment arms of the major abductor and adductor muscles of the metacarpophalangeal (MCP) joint of each finger in the hand; secondly, to assess the effect of change in joint angle on these moment arms; and thirdly, to determine if there are differences in a given flexor or extensor\'s muscle moment arms between the joints it spans on a given finger, and across its tendon slips to multiple fingers. The tendon-excursion method was used to measure instantaneous muscle moment arms in nine fresh-frozen entire forearm cadaver specimens. Joint flexion angle was found to have significant effects on the moment arms of the extensor muscles at the MCP and PIP joints (p < 0.05). In contrast, the digital flexor muscles maintained relatively constant moment arms through the range of joint flexion. The moment arms of the digital flexors and extensors spanning multiple joints in a finger were largest at the MCP joints and smallest at the DIP joints. The findings demonstrate greater torque generating capacity for tasks such as grasping at the proximal interphalangeal joints, and smaller torque capacity for finer movement control at the distal interphalangeal joints. The dataset generated in this study may be useful in the development and validation of computational models used in surgical planning, and rehabilitation.

Thumb metacarpophalangeal instability is commonly found in conjunction with trapeziometacarpal osteoarthritis. If not corrected, it can have detrimental effects on the outcome. The authors describe the two types of metacarpophalangeal deformities - hyperextension and valgus - their pathophysiology and the surgical repair techniques available to surgeons. An algorithm for treating this instability is presented.

Due to the complex shape of the carpometacarpal (CMC) joint, a fixed joint collapse deformity of the thumb CMC (CMC1) and metacarpophalangeal (MCP1) joint can present in advanced stages of CMC1 osteoarthritis (OA), resulting in adduction of the first metacarpal (MC1) and hyperextension of the MCP1.
To determine whether joint collapse deformity is associated with worse pain and/or functional impairment.
Cross-sectional.
This study used the baseline data from 140 patients enrolled in a longitudinal study of treatment for CMC1 OA. (efficacy of combined conservative therapies on clinical outcomes in patients with CMC1 OA). Joint collapse was determined at baseline using a pinch gauge. Pain was assessed on a visual analog scale (0-100) and function was assessed using the Functional Index for Hand Osteoarthritis questionnaire (0-30). Pain and function and the presence of joint collapse were entered in a univariate logistic regression. The final adjusted model for pain and joint collapse included age and sex. The final adjusted model for function and joint collapse included Kellgren Lawrence grade and grip strength.
About 20% of participants demonstrated joint collapse on the tip-pinch test. The presence of joint collapse was associated with increased pain in the unadjusted [P = .047, OR = 2.45, 95% CI (1.01, 5.910)] and adjusted model [P = .049, OR = 2.45, 95% CI (1.00, 5.98)].
CMC1 patients with joint collapse reported increased pain compared with those without joint collapse. Future studies should determine the relationship between thumb hypermobility and joint collapse and how to manage these conditions effectively.