The Effect of Thumb Metacarpophalangeal Hyperextension on Thumb Axial Load and Lateral Pinch Force in a Cadaver Model of Thumb Trapeziectomy and Flexor Carpi Radialis Suspensionplasty.

PURPOSE: The purpose of our study was to investigate, in a cadaver model, the effect of increasing thumb metacarpophalangeal (MCP) joint hyperextension on thumb axial load and key pinch force after thumb trapeziectomy and flexor carpi radialis suspensionplasty. We developed a cadaveric model to test whether thumb MCP joint hyperextension after trapeziectomy would have a negative effect on key pinch force and increase loads across a reconstructed thumb carpometacarpal (CMC) joint. METHODS: We created a cadaveric biomechanical model that varied thumb MCP joint hyperextension while measuring thumb CMC axial and key pinch force under standardized loads. Direct observations were made of how key pinch and axial thumb CMC force change with increasing thumb MCP joint hyperextension. We measured the thumb key pinch force and axial thumb CMC joint load with the thumb MCP joint in 0°, 10°, 20°, 30°, 40°, 50°, and 60° of hyperextension. RESULTS: There was a 0.88 N (2.4%) increase in axial force across the thumb CMC per every 10° of increasing thumb MCP joint hyperextension. We found a 0.53 N (4.4%) reduction in key pinch force for every 10° of increasing thumb MCP joint hyperextension. Therefore, at 60° of thumb MCP joint hyperextension, the axial force across the thumb CMC increased by 5.3 N (14.6%) and the key pinch force was weakened by 3.2 N (26.6%). CONCLUSIONS: With progressive thumb MCP joint hyperextension after thumb CMC arthroplasty, we found a decrease in key pinch force and an increase in axial thumb CMC joint force. The decrease in key pinch force was larger than the relatively small increase in thumb CMC force. CLINICAL RELEVANCE: This study helps elucidate the biomechanics of the thumb CMC joint after resection arthroplasty with thumb MCP joint hyperextension and helps understand the interplay between these 2 conditions.

Metacarpal Neck Osteochondroma: An Atypical Cause of "Trigger Finger".

"Locking" of the digits is a relatively common patient complaint in hand surgery. Typically, this phenomenon arises from either triggering of tendons at the A1 pulley or subluxation of tendons around the metacarpal head. Although trigger digit and sagittal band injury comprise most diagnoses, clinicians must be aware of rarer entities that alter the underlying osseous anatomy and predispose the digits to "locking." Here, we present a case of metacarpal neck osteochondroma causing subluxation of the index metacarpophalangeal joint radial collateral ligament.

Predictive Value of Magnetic Resonance Imaging-detected Tenosynovitis of the Metacarpophalangeal and Wrist Joints for the Development of Rheumatoid Arthritis among Patients with Undifferentiated Arthritis.

Objective The early diagnosis of rheumatoid arthritis (RA) improves disease outcomes. Using bilateral magnetic resonance imaging (MRI), we investigated whether or not tenosynovitis at the level of the metacarpophalangeal (MCP) and wrist joints, as well as non-symmetrical versus symmetrical involvement, predicts RA development in undifferentiated arthritis (UA) patients. Methods We collected the clinical and serological findings as well as bilateral gadolinium-enhanced 1.5-T MRI data of UA patients after 1 year. A multivariate logistic regression analysis was used to determine the association of tenosynovitis in UA with RA development. Ninety-one UA patients from the Nagasaki Early Arthritis Clinic who did not meet the 2010 European League Against Rheumatism/American College of Rheumatology classification criteria for RA were selected. Tenosynovitis at the MCP and wrist joints was scored according to the RA MRI scoring system. Results Of these 91 UA patients, 29 (31.9%) progressed to RA, with a median disease duration of 3 months, despite only 10.9% being positive for anti-cyclic citrullinated peptide antibody (ACPA). A univariate analysis showed higher MCP tenosynovitis scores, MCP flexor tenosynovitis, and symmetrical MCP tenosynovitis in the RA development group than in the non-development group (p<0.05). A multivariate analysis showed that symmetrical MCP tenosynovitis was independently associated with RA development after adjusting for age, gender, swollen joint count, C-reactive protein level, and ACPA positivity (odds ratio: 4.96). The presence of symmetrical MCP tenosynovitis had low sensitivity (35%) but high specificity (87%) for RA development. Conclusion MRI-detected tenosynovitis, especially symmetrical findings at the MCP joint, is predictive of RA development in a UA population with low ACPA positivity.

Locked thumb metacarpophalangeal joint due to sesamoid bone entrapment: A case report and review of literature.

Locked thumb metacarpophalangeal (MCP) joint has been known as a relatively rare condition. We present a case of a 25-year-old male presented with a traumatic locked thumb MCP joint of the right hand. Clinical presentation showed the joint was in a hyperextention position and resistant to active flexion and extension. The radial sesamoid was distally displaced on X-ray film and entrapped into the joint on CT scan. The mechanism of the locked MCP joint was thought as a "pull-hook lock" between the pointed proximal edge of the sesamoid and the deformed volar groove on the cartilaginous surface of the metacarpal head. Surgical treatment included partially releasing the insertion of the abductor pollicis brevis (APB) and flexor pollicis brevis (FPB) muscles to move the entrapped radial sesamoid, and resurfacing the deformed metacarpal head.

Outcomes of Pyrocarbon Arthroplasty in Metacarpophalangeal Joints Affected by Rheumatoid Arthritis.

BACKGROUND: Rheumatoid arthritis (RA) affecting the metacarpophalangeal (MCP) joint may warrant arthroplasty. The purpose of this study was to investigate implant survivorship, complications, radiographic outcomes, and clinical outcomes in patients undergoing MCP arthroplasty with a pyrocarbon implant to treat RA. METHODS: In all, 124 MCP joint pyrocarbon arthroplasties in 40 patients performed to treat RA were reviewed. Operations were at the index (n = 43, 35%), middle (n = 33, 27%), ring (n = 27, 22%), and small (n = 21, 17%) fingers from 1998 to 2009 in 105 (85%) female and 19 (15%) male joints with a mean age of 54 ± 11 years. Mean postoperative follow-up was 6 ± 3 years. All patients achieved at least 2 years of follow-up. RESULTS: Rates of implant survivorship at 1, 2, 5, and 10 years were 98%, 98%, 90%, and 81%, respectively. Fifteen percent (n = 18) of arthroplasties underwent revision at a mean 5 ± 3 years postoperatively. The overall reoperation rate was 29% (n = 36). Rates of survival from reoperation at 1, 2, 5, and 10 years were 85%, 84%, 76%, and 68%, respectively. Complications occurred in 32% (n = 40). Pain ratings improved postoperatively (P < .01). Arc of motion improved from 37 ± 21 to 43 ± 19 (P = .03). Both appositional and oppositional strength improved after surgery; however, there was no improvement in grip strength (P < .01). CONCLUSIONS: Metacarpophalangeal arthroplasty with a pyrocarbon implant demonstrated reliable improvement in pain and arc of motion in patients with RA. Complication and overall reoperation rates were high, while 1 in 10 undergo revision within 5 years postoperatively.

The silicone metacarpophalangeal joint arthroplasty: An in-vitro analysis.

BACKGROUND: Silicone is still the gold standard implant in metacarpophalangeal arthroplasty. Whereas the clinical results are acceptable, in follow-ups with >10 years, high rates of implant fracture are common, and 5 to 7% of implants required revision. This work's purpose is to analyse the hypothesis that the joint flexion amplitude has a relevant effect on bone strain level, implant stress and bone-implant micromotion, which can reflect an increase in the risk of bone resorption/fatigue failure, implant fracture and osteolysis. METHODS: To experimentally predict the cortical loading behaviour, composite metacarpals and proximal phalanges were used in intact and implanted states. A finite element model was developed to evaluate the structural behaviour of cancellous bone and implant. This model was validated by comparing cortical strain and load-displacement curve with experimental measurements. FINDINGS: Bone strain changes between the intact and the implanted states showed a load transfer effect from the cortical to the cancellous bone that increases significantly with the flexion's amplitude rise. The peak implant stress occurred in the flexion amplitudes further away from the implant neutral angle. The highest implant pistoning motion and the highest phalanx cancellous-bone strain occurred simultaneously at the maximum flexion amplitude. INTERPRETATION: Limiting joint flexion range will be helpful to reduce the strain-shielding effect on cortical bone, minimizing the overload effect on cancellous bone and decreasing the stress levels and the pistoning motion on the implant, ultimately contributing to the longevity of silicone arthroplasty.

Quantification of joint mobility limitation in adult type 1 diabetes.

Aims: Diabetic cheiroarthropathies limit hand mobility due to fibrosis and could be markers of a global profibrotic trajectory. Heterogeneity in definitions and lack of a method to measure it complicate studying associations with organ involvement and treatment outcomes. We measured metacarpophalangeal (MCP) joint extension as a metric and describe magnetic resonance (MR) imaging determinants of MCP restriction. Methods: Adults with type 1 diabetes were screened for hand manifestations using a symptom questionnaire, clinical examination, and function [Duruoz hand index (DHI) and grip strength]. Patients were segregated by mean MCP extension (<20°, 20°-40°, 40°-60°, and >60°) for MR imaging (MRI) scanning. Patients in the four groups were compared using ANOVA for clinical features and MRI tissue measurements (tenosynovial, skin, and fascia thickness). We performed multiple linear regression for determinants of MCP extension. Results: Of the 237 patients (90 men), 79 (33.8%) with cheiroarthropathy had MCP extension limitation (39° versus 61°, p < 0.01). Groups with limited MCP extension had higher DHI (1.9 vs. 0.2) but few (7%) had pain. Height, systolic blood pressure, and nephropathy were associated with mean MCP extension. Hand MRI (n = 61) showed flexor tenosynovitis in four patients and median neuritis in one patient. Groups with MCP mobility restriction had the thickest palmar skin; tendon thickness or median nerve area did not differ. Only mean palmar skin thickness was associated with MCP extension angle on multiple linear regression. Conclusion: Joint mobility limitation was quantified by restricted mean MCP extension and had structural correlates on MRI. These can serve as quantitative measures for future associative and interventional studies.

Outcomes of Surface Replacement Arthroplasty in Metacarpophalangeal Joints Affected by Noninflammatory Arthritis.

BACKGROUND: The purpose of this study was to investigate the outcomes of surface replacement arthroplasty (SRA) for noninflammatory arthritis of the metacarpophalangeal (MCP) joint. METHODS: Records from 20 SRAs performed between 1995 and 2017 in 17 patients with noninflammatory arthritis affecting the MCP joint were retrospectively reviewed. The mean follow up was 6.6 years. RESULTS: Three arthroplasties (15%) underwent 4 revision operations. The 2-, 5-, 10-, and 15-year rates of survival from surface replacement implant revision were 90%, 90%, 79%, and 79%, respectively. Major complications occurring in revised joints included arthrodesis (n = 1) and amputation (n = 1). The overall reoperation rate was 35%. The 2-, 5-, 10-, and 15-year rates of overall reoperation-free survival were 75%, 69%, 60%, and 60%, respectively. CONCLUSIONS: Pain ratings and MCP arc of motion significantly improved following arthroplasty. Metacarpophalangeal SRA for noninflammatory arthritis can improve arc of motion and pain. Revision is uncommon; however, 1 in 3 joints requires reoperation.

Long-term survival of 2997 finger metacarpophalanageal joint arthroplasties from the Norwegian Arthroplasty Register.

We present the long-time survival of 2997 primary metacarpophalangeal (MCP) joint implants from the Norwegian Arthroplasty Register from 1994 to 2019. Six different implants were compared in terms of survival and risk of revision. The majority of implants were inserted in patients diagnosed with inflammatory diseases and in women. The overall survival was found to be 94%, 89%, 85% and 84% after 5, 10, 15 and 20 years. The most prevalent reason for revision was a fractured prosthetic component, and the second was pain. Implants inserted in the right hand and in younger patients had a higher risk for revision. Sex, type of implant, finger treated, one- or two-component prosthesis, and inflammatory or non-inflammatory conditions did not influence the survival. The frequency of MCP joint implantations decreased during the observation period. Our data show satisfactory long-term survival of the MCP implants, with no difference found between implant types or concepts.Level of evidence: II.

Corrigendum: Quantification of joint mobility limitation in adult type 1 diabetes.

[This corrects the article DOI: 10.3389/fendo.2023.1238825.].

Current Management of Trigger Digit in Rheumatoid Arthritis Patients: A Survey of ASSH Members.

BACKGROUND: Traditional dogma regarding management of rheumatoid arthritis (RA) patients with trigger digit symptoms holds that A1 pulley release should be avoided. Surgical release was thought to further destabilize the metacarpophalangeal joint. Biologic disease modifying anti-rheumatic drugs (DMARDs) have limited the development of hand deformities. Despite advances in RA treatment, many textbooks continue to discourage release of the A1 pulley in RA patients. The aim of this study was to determine if this belief is consistent with current trends in surgical management of trigger digits in patients with RA. METHODS: Active Members of the American Society for Surgery of the Hand (ASSH) were surveyed on their training and current practices as related to RA patients with trigger digits. RESULTS: Five hundred three surveys were completed (16% response rate). During training, 55% of ASSH Members were taught to avoid releasing the A1 pulley in RA patients. Seventy-one percent of respondents currently release the A1 pulley in RA patients with no preexisting deformities, no tenosynovial thickening, or if tenosynovectomy and flexor digitorum superficialis slip excision fail to relieve triggering. Forty percent reported that their practice has evolved toward more frequent release of the A1 pulley in RA patients. CONCLUSION: The majority of ASSH Active Members were taught during training to avoid surgical release of the A1 pulley in RA patients to prevent acceleration of finger deformities. Indications and contraindications for A1 pulley release are evolving along with the improved natural history of RA associated with the use of biologic DMARDs.

Long-term Outcomes of MCP Surface Replacement Arthroplasty in Patients With Rheumatoid Arthritis.

Background: Surface replacement arthroplasty (SRA) can be used in the treatment of rheumatoid arthritis (RA) affecting the metacarpophalangeal (MCP) joint. The authors of this study sought to investigate the outcomes of MCP SRA in patients with RA. Methods: Retrospective review of medical records and an institutional joint registry were used to gather data on 80 MCP SRAs performed in 27 patients with RA. Data collected included demographics, SRA revisions, reoperations, complications, pain, and MCP arc of motion. Results: The mean postoperative follow-up was 9.5 years (range, 2.1-20.5 years), with all SRAs achieving at least 2 years of follow-up. Thirteen digits (16%) underwent revision arthroplasty, and 29 (36%) required reoperation. The 5-, 10-, 15-, and 20-year rates of survival from implant revision were 95%, 85%, 80%, and 69%, respectively. The 5-, 10-, 15-, and 20-year rates of survival from overall reoperation were 80%, 65%, 55%, and 46%, respectively. Metacarpophalangeal joint arc of motion, grip strength, and pain levels significantly improved following surgery. Conclusions: Metacarpophalangeal SRA can offer benefit to patients with RA for improvement in function and pain. High overall reoperation rates remain concerning; however, most do not involve arthroplasty revision.

Intraoperative Active Motion Confirmation During Wide-Awake Local Anesthesia No Tourniquet Surgery.

As a recent advance in the field of hand surgery, the wide-awake local anesthesia no tourniquet surgical technique-performed using an epinephrine-containing local anesthetic without a tourniquet while the patient is awake-has attracted attention. The wide-awake local anesthesia no tourniquet technique has been indicated for surgeries such as trigger release, soft tissue tumor excision, surgery for Dupuytren contracture, thumb carpometacarpal arthroplasty, or any other tendon, nerve, or ligament surgeries, requiring intraoperative active motion confirmation. Herein, the surgical procedures performed with the wide-awake local anesthesia no tourniquet technique have been described; moreover, the indications and precautions of this technique have been reconsidered.

Management of Complex Kaplan's dislocation by Open Dorsal Approach - A Case Report.

Introduction: Finger dislocations account for 5% of upper extremity injuries. Metacarpophalangeal (MCP) joint/Kaplan dislocations post-trauma are of rare occurrence. An MCP joint dislocation is considered simple when it can be managed by closed reduction and considered complex when open reduction is necessary. Case Report: Here, we present a rare case of dorsal Kaplan dislocation of left second MCP joint in an 11 years old male child, which was managed by open dorsal approach with stable reducion and good functional outcome. Conclusion: We experienced closed reduction should not be tried in cases of complex dorsal dislocations. The dorsal approach of complex MCP dislocation is found to be safe and simple even in hands of inexperienced surgeons which may or may not need division of deep transverse ligament.

Treatment of Severe Ulnar Instability of the MCP Joint Improves Function in LRTI Arthroplasty for Osteoarthritis of the Thumb CMC Joint.

Background Comorbidity in the metacarpophalangeal joint (MCPj) of the thumb, i.e., hyperextension or ulnar collateral instability, could affect the outcome of arthroplasty in the thumb carpometacarpal joint (CMCj). Objective In a retrospective study, we evaluated the effect of arthrodesis of the MCPj for thumbs with unstable MCPj and simultaneous ligament reconstruction tendon interposition (LRTI) arthroplasty for the CMCj in terms of strength, function, and patient satisfaction. Patients and Methods A total of 69 thumbs treated with a LRTI arthroplasty of the CMCj were included. In 14 of those cases, an arthrodesis of the MCPj was performed as well. In 12 thumbs, both procedures were done simultaneously; in one case MCPj arthrodesis followed LRTI arthroplasty, whereas one patient already had MCPj arthrodesis at time of LRTI arthroplasty. Those 14 thumbs were compared with the control group of 55 thumbs who had only undergone LRTI. At a mean follow-up of 4 to 5 years (mean 54 [10-124] months) postoperative assessments included range of motion (ROM) of the CMC, MCP, and interphalangeal (IP) joint of the thumb, as well as any instability of the MCPj. Pinch and grip strength were examined, also the visual analogue scale (VAS), patient satisfaction, QuickDASH, PRWE-Thumb, and the Kapandji's Opposition Score. Radiologically, proximalization of the first metacarpal bone was measured. Student's t -test was used to determine significance, p < 0.05 was considered significant. Results Additional arthrodesis of the MCPj provided no significant difference of function in thumbs that only had a hyperextension-instability. However, in thumbs with marked ulnar instability, stronger pinch-grip was obtained with arthrodesis, compared with only LRTI. Conclusion In patients with advanced painful thumb CMCj osteoarthritis, we recommend (simultaneous) arthrodesis of the MCPj, to allow a stable thumb grip if there is additional marked ulnar collateral ligament instability. Level of Evidence This is a Level III, retrospective comparative study.

Biomechanical analysis of metacarpophalangeal joint arthroplasty with metal-polyethylene implant: An in-vitro study.

BACKGROUND: The most common implant options for the metacarpophalangeal joint arthroplasty include silicone, pyrocarbon and metal-polyethylene. A systematic review of outcomes of silicone and pyrocarbon implants was conducted; however, a similar exercise for metal-polyethylene implants revealed a scarcity of published results and lack of long-term follow-up studies. The aim of the present work is to test the hypothesis that the magnitude of metacarpophalangeal joint cyclic loads generates stress and strain behaviour, which leads to long-term reduced risk of metal-polyethylene component loosening. METHODS: This study was performed using synthetic metacarpals and proximal phalanges to experimentally predict the cortex strain behaviour for both intact and implanted states. Finite element models were developed to assess the structural behaviour of cancellous-bone and metal-polyethylene components; these models were validated by comparing cortex strains predictions against the measurements. FINDINGS: Cortex strains in the implanted metacarpophalangeal joint presented a significant reduction in relation to the intact joint; the exception was the dorsal side of the phalanx, which presents a significant strain increase. Cancellous-bone at proximal dorsal region of phalanx reveals a three to fourfold strain increase as compared to the intact condition. Interpretation The use of metal-polyethylene implant changes the strain behaviour of the metacarpophalangeal joint yielding the risk of cancellous-bone fatigue failure due to overload in proximal phalanx; this risk is more important than the risk of bone-resorption due to the strain-shielding effect. By limiting the loads magnitude over the joint after arthroplasty, it may contribute to the prevention of implant loosening.

The Effect of Metacarpophalangeal Joint Hyperextension on Outcomes in the Surgical Treatment of Carpometacarpal Joint Arthritis.

Purpose In the surgical treatment of thumb carpometacarpal (CMC) joint arthritis, the effect of mild preoperative metacarpophalangeal (MCP) hyperextension on postoperative functional outcomes is unknown. We sought to examine outcomes after surgical treatment of CMC arthritis in patients with and without mild preexisting MCP deformity. Methods A retrospective review was conducted to analyze the functional outcomes of patients treated for CMC arthritis at a single institution from March 1998 to May 2009. All patients were treated with one of two standard CMC arthroplasty procedures-either ligament reconstruction tendon interposition (LRTI) or a Weilby procedure-and none had additional procedures to address MCP hyperextension. Pre- and postoperative assessments included pinch and grip strength, degree of MCP hyperextension, and thumb radial and palmar abduction. A t -test was used to assume unequal variances. Results A total of 203 patients were followed for an average of 27.3 months. Patients were divided into two groups: (1) patients without preoperative MCP hyperextension (167 patients) and (2) patients with mild but untreated preoperative MCP hyperextension (≤ 30 degrees; 36 patients). All patients underwent either a Weilby procedure (118 patients) or an LRTI; 85 patients). The main difference between techniques was the use of the abductor pollicis longus tendon as a post to secure the flexor carpi radialis (Weilby) or the use of a bone tunnel in the first metacarpal (LRTI). Analysis of the preoperative data showed no difference in the baseline parameters among both the groups, with the exception of MCP hyperextension. Postoperatively, neither the type of CMC procedure nor the presence of MCP hyperextension demonstrated any significant differences in key pinch, tip pinch, grip strength, and radial or palmar abduction of the thumb between the groups. Conclusion There were no statistically significant differences in improvement of functional outcomes after surgery when comparing patients without preoperative MCP hyperextension to patients with untreated MCP hyperextension of less than 30 degrees. Level of Evidence Level III, retrospective comparative study.

Vascularized transfer of two coherent toe joints in simultaneously reconstructing MCP and PIP of a mutilated finger.

BACKGROUND: The reconstruction of metacarpal- and interphalangeal joints after severe hand injuries has been proven to be challenging. Commonly used procedures like arthrodesis, amputation or ray resection of the finger compromise the functionality of the injured finger. Especially for young patients, the restoration of all functions of the fingers is a priority. Local tissue transfers for finger joint reconstructions is not an option due to inacceptable donor site morbidity; microsurgical tissue transfers in terms of free toe joint transfers have proven to be a valuable method. METHODS: We present the case of a patient who suffered an excessive injury from a circular saw to his dominant hand. The MCP Joints of D2-D4 were fully destroyed, along with the PIP joint of a subtotally amputated D4. Arteries, nerves and tendons could be coapted directly, while primarily reconstructing of the finger joints was impossible. To ensure a possible regain of full functionality, two coherent joints, the MTP and the PIP of one toe, were transferred to the ring finger as a single transplant, reconstructing the MCP and the PIP joints of the injured finger in a one step procedure. Additionally the MCP joint of the D2 was reconstructed by the use of a free PIP-joint transfer, further the MCP joint of the D3 was replaced by an MCP endoprosthesis. RESULTS: After a follow up of 3 years the patient displayed full function of his dominant hand including sensitivity, and has gone back to manual work without limitations. The result was cosmetically acceptable and the donor site defect was easily being tolerated by the patient who is playing soccer in the regional soccer league. CONCLUSION: Free double toe joint transfer has been proven feasible in this patient. While transferring a single toe joint to reconstruct a finger joint is a well-established method, our review of the latest literature showed no case of a free transfer of two coherent joints and three transplanted joints in one hand. The applied microsurgical technique should be considered by microsurgically trained hand surgeons for the treatment of comparable severe hand injuries. In comparison to the most common procedures described for the repair and reconstruction of severely injured finger joints this method showed superior results.

Palmar plate capsulodesis for thumb metacarpophalangeal joint hyperextension in association with trapeziometacarpal osteoarthritis.

Hyperextension of the thumb metacarpophalangeal (MCP) joint is frequently seen with trapeziometacarpal osteoarthritis, but there is no consensus on the indication for, or type of, treatment. We re-examined 12 thumbs at a mean of 9 (range 6-13) years following MCP capsulodesis using a suture anchor performed with trapeziectomy. Mean MCP hyperextension improved from 45° pre-operatively to 19° at 1 year post-operatively. At 9 years follow-up, it had increased to 30° but was still significantly better than pre-operatively (p = 0.007). Mean MCP flexion was 37° and near normal opposition was retained. The median pain score had improved from 5.5 to 1 (p = 0.002). Thumb key and tip pinch and hand grip strength showed no significant change from pre-operative values. No thumb MCP had symptomatic radiological degeneration. Our results suggest that MCP capsulodesis preserves a useful range of MCP flexion but stretches out over time. However, this did not result in increased pain or thumb weakness.

Utility of MRI for diagnosing complete tears of the collateral ligaments of the metacarpophalangeal joints of the lesser digits.

BACKGROUND: MRI has been shown to be highly accurate in assessing collateral ligament injuries of the metacarpophalangeal joint (MPJ) of the thumb. The purpose of this study is to evaluate the accuracy of MRI for diagnosing collateral ligament tears of the MPJ of the fingers. Our hypothesis is that MRI would accurately detect complete tears of collateral ligaments of the lesser digit MPJs. METHODS: We retrospectively evaluated 22 digits in 20 patients undergoing finger MPJ collateral ligament repair. All patients had preoperative MRI scans. The findings on preoperative imaging studies were compared to the intraoperative findings. RESULTS: All patients had surgically confirmed complete tears of the collateral ligament in question. In 8 of 22 MRI scans (36 %), the preoperative imaging study was inaccurate. Of these eight patients, MRI was interpreted as no tear in one and a partial tear in seven. The sensitivity of MRI for diagnosing a complete tear was 64 %. In all three digits in which 3-T MRI scanning was utilized and documented, the preoperative imaging results did not correlate with the intraoperative findings. CONCLUSIONS: Although MRI can be considered a useful adjunct to evaluating patients with collateral ligament injuries of the fingers, the sensitivity is poor and the imaging results can underestimate the extent of injury. In light of this, the emphasis for determining appropriate course of treatment remains on history and mechanism of injury, physical examination, and patient disability.