ArUco-based stylus reliability for reproductible 3D digitalisation of shoulder cartilage contours.

Imaging techniques in anatomy have developed rapidly over the last decades through the emergence of various 3D scanning systems. Depending on the dissection level, non-contact or tactile contact methods can be applied on the targeted structure. The aim of this study was to assess the inter and intra-observer reproducibility of an ArUco-based localisation stylus, that is, a manual technique on a hand-held stylus. Ten fresh-frozen, unembalmed adult arms were used to digitalise the glenoid cartilage related to the glenohumeral joint and the contour of the clavicle cartilage related to the acromioclavicular joint. Three operators performed consecutive digitalisations of each cartilage contour using an ArUco-based localisation stylus recorded by a single monocular camera. The shape of each cartilage was defined by nine shape parameters. Intra-observer repeatability and inter-observer reproducibility were computed using an intra-class correlation (ICC) for each of these parameters. Overall, 35.2 ± 2.4 s and 26.6 ± 10.2 s were required by each examiner to digitalise the contour of a glenoid and acromioclavicular cartilage, respectively. For most parameters, good-to-excellent agreements were observed concerning intra-observer (ICC ranging between 0.81 and 1.00) and inter-observer (ICC ranging between 0.75 and 0.99) reproducibility. To conclude, through a fast and versatile process, the use of an ArUco-based localisation stylus can be a reliable low-cost alternative to conventional imaging methods to digitalise shoulder cartilage contours.

Recurrent carpal tunnel syndrome: Outcomes after neurolysis and synovial flap.

OBJECTIVES: If symptoms recur after primary neurolysis of the median nerve, surgical revision is required. Soltani et al. (2013) demonstrated that surgical revision with vascularized flap coverage had a higher success rate (86%) than surgical revision without a flap (75%). The aim of this retrospective study was to present clinical outcomes in 36 cases of secondary open neurolysis of the median nerve, with synovial flap in case of recurrent carpal tunnel syndrome. METHOD: Thirty-three patients (36 hands) who had undergone secondary neurolysis of the median nerve combined with synovial flap coverage between 2012 and 2019 were selected for this study. We included only recurrent carpal tunnel syndrome cases presenting with scarring of the transverse carpal ligament or epineural fibrosis of the median nerve and with a symptom-free period of at least 3 months. The results were ranked on a 4-point scale as excellent, good, null or poor, depending on progression at last follow-up. RESULTS: Descriptive analysis showed that 80% of patients had a positive outcome (excellent 33%, good 47%), 6% null outcome and 14% poor outcome. CONCLUSION: This is an interesting, relatively non-invasive surgical option, and should be part of the therapeutic armamentarium for recurrent carpal tunnel syndrome in case of adherence of the nerve to the transverse carpal ligament.

Midsectional Magnetic Resonance Imaging Analysis of the Sigmoid Notch of the Distal Radioulnar Joint.

Purpose This study describes the anatomy and analyzes the variations of the midsectional morphology of the sigmoid notch. Methods The wrists of 50 patients with suspected scaphoid fracture were evaluated by magnetic resonance imaging (MRI). Sigmoid notch length, volar and dorsal rim heights, insertion length of the volar radioulnar ligament, and Tolat morphology classification were measured on T1-weighted axial plane MRI. Ulnar variance and distal radioulnar joint (DRUJ) inclination were assessed on anteroposterior radiographs. Results The most common sigmoid notch shapes were types C (C-shaped, 60%) and B (ski-slope, 30%), followed by types D (S-shaped, 6%) and A (flat, 4%). Types A and B had a flat dorsal rim (mean 0.77 ± 1.09 mm, range 0.0-1.54 mm, and mean 0.22 ± 0.3 mm, range 0.0-0.76 mm, respectively). Types C and D had more prominent dorsal rims (means 1.47 ± 0.59 mm, range 0.66-2.57 mm, and mean 1.6 ± 0.97 mm, range 0.8-2.68 mm, respectively). The average volar lip length was 1.60 ± 1.11 mm (range, 0.0-4.10). The dorsovolar length of the radius was 18.4 ± 2.01 mm; the length of the sigmoid notch was 14.3 ± 1.73 mm. The type of sigmoid notch according to Tolat was significantly associated with volar lip length ( p = 0.005). The type of sigmoid notch was not associated with ulnar variance or DRUJ inclination. The length of the sigmoid notch was significantly associated with the type of sigmoid notch ( p = 0.005). The analysis demonstrated a negative association between the sigmoid notch length and the volar insertion of the radioulnar ligament ( p = 0.019). Conclusions The transversal morphology of the sigmoid notch was either flat with the least congruence (similar to type A of Tolat), with volar congruence only (similar to type B), or with volar and dorsal congruence (similar to types C and D). A shorter sigmoid notch may be compensated by a broader insertion of the volar radioulnar ligament. Clinical Relevance The measurements and correlations demonstrated in this study can be a guide when considering reconstructive procedures or dealing with the instability of the DRUJ.

Perioperative Morbidities in Distal Radius Fractures Treated Using Locking Plates in the Super-Elderly Population: A Retrospective Study.

Purpose: Currently, there is no consensus on the treatment of distal radius fractures in the super-elderly population. The aim of this study was to evaluate the perioperative morbidities and the need for rehabilitation care after a distal radius fracture treated with locking plates among patients aged 85 years or older. Methods: A retrospective study was conducted in all patients aged 85 years or older who underwent open surgical treatment using a locking plate for an isolated distal radius fracture from January 2013 to December 2018 at a level 1 trauma center. The occurrence of minor complications (tendinopathy, neuropathy, carpal tunnel syndrome, and infection), major complications (complex regional pain syndrome, nonunion, loss of reduction, intra-articular screw, and hardware failure), and the need for revision surgery were recorded. The need and timing of rehabilitation were also documented. A nested case-control study was performed to evaluate predictive factors associated with the need for inpatient rehabilitation. Results: The majority of fractures were AO type A, numbering 88 (55.7%), followed by 64 type C (40.5%), and then 6 type B (3.8%). The overall complication rate among the 158 included patients was 17% (n = 26), with 12 (7.6%) having minor complications and 14 (8.9%) having major complications. Inpatient rehabilitation was required for one-third of the patients (n = 59), and 11 (7%) were definitively discharged to a nursing home. The place of residence before the fracture, American Society of Anesthesiologist score, and the type of anesthesia were associated with a need for inpatient rehabilitation. Conclusions: Overall, this study suggests that perioperative morbidity of distal radius fractures treated using a locking plate is acceptable even in the super-elderly population. Nevertheless, given the frequent requirement for rehabilitation, the impact of age cannot be ignored. Type of Study/level of evidence: Therapeutic IV.

The influence of sagittal deformity of the distal radius on pronosupination: a cadaver study.

We performed a cadaver study using seven fresh-frozen adult upper limbs to assess the impact of increasingly larger distal radial deformity in the sagittal plane on the range of motion in pronation/supination. Three palmar (20°, 30° and 40° angulations) and three dorsal (10°, 20° and 30° angulations) tilt deformities, without any radial shortening, were simulated by performing a radial osteotomy and using custom-made three-dimensional-printed anterior plates. We measured the maximum unconstrained pronation and supination before the osteotomy and after each induced deformation. There was a decrease in the median pronation and supination values for all palmar and dorsal tilt deformities. The pronation range was more impaired than the supination range, and dorsal tilt deformities caused the greatest loss in forearm rotation. Our results suggest that forearm rotation in both pronation and supination is reduced as soon as 10° to 20° distal radial deformity occurs in the palmar or dorsal direction.

Ulna hook plate osteosynthesis for ulna head fracture associated with distal radius fracture.

BACKGROUND: Distal ulna head or neck fracture is commonly associated with distal radius fracture. Treatment of these fractures remains controversial. Plate osteosynthesis is commonly performed. The purpose of this study was to observe clinical and radiological outcomes in ulna hook plate osteosynthesis for distal ulna fracture associated with distal radius fracture. MATERIALS AND METHODS: This retrospective study between 2010 and 2018 included patients presenting combined displaced distal ulna fracture and distal radius fracture who were treated with ulna hook plate osteosynthesis. Patient evaluation included pain measurement with the visual analog scale, wrist range of motion, grip and pinch strengths, Quick Disabilities of the Arm, Shoulder and Hand (Q-DASH) score, and Mayo wrist score. Preoperative radiographs were reviewed to classify the distal ulna fracture according to Biyani. Bone union was evaluated on postoperative X-rays. At final follow-up, the usual radiographic parameters were measured and distal radioulnar joint (DRUJ) osteoarthritis was assessed. RESULTS: A total of 48 patients were included. Mean age was 63 years old and mean follow-up was 28 months. According to the Biyani classification, there were 12 type I, 4 type II, 8 type III, and 24 type IV distal ulna fractures. Wrist flexion was 60°, extension 57°, pronation 85°, and supination 80°. Grip strength was 21 kg (86% of the uninjured opposite side). Pinch strength was 6.6 kg (92% of the uninjured opposite side). Clinical scores were very good to excellent, with a mean Q-DASH of 12 and a Mayo wrist score of 90. Discomfort or pain due to the implant that required implant removal was reported in 29%, and was higher in younger patients. Nonunion was observed in two cases and secondary implant displacement in one case. These three cases required secondary intervention with ulna head resection, which was higher in Biyani type IV. DRUJ osteoarthritis was observed in 12 patients (31%) and was higher in older patients. CONCLUSIONS: Ulna hook plate fixation gives good clinical results and a high rate of fracture union, but complications are common. Implant irritation is a frequent complication, especially in young patients, and often requires implant removal. LEVEL OF EVIDENCE: IV.

Reliability of radio-ulnar and carpal alignment measurements in the wrist between radiographs and 3D imaging.

OBJECTIVE: Conventional radiography is the first modality to investigate the radio-ulno-carpal joint in the event of trauma or instability. This study sought to determine the reliability of cone beam computer tomography (CBCT) and scout of view in evaluating carpal alignment compared with conventional radiographs in order to assess the influence of wrist kinematics on usual measurements. MATERIALS AND METHODS: We prospectively recruited 305 patients who successively underwent plain radiography and CBCT. 51 patients with prior acute unilateral wrist trauma were eligible for entry into the study (mean age of 39 years). Three blinded readers performed the measurements separately. The axial method and bony axial lines defined previously in the literature were applied, with three categories of measurements performed, consisting of distal radio-ulnar, radiocarpal, and radio/carpometacarpal measurements. Intraclass correlation coefficients (ICCs) for paired t-test were calculated to assess inter- and intra-observer agreements. RESULTS: Inter-observer agreement was very high (>0.94) for all modalities. Intra-observer reliability between scout view and CBCT was almost perfect for all measurements. Intra-observer reliability between radiograph and scout view/CBCT was perfect for distal radio-ulnar measurements, substantial for radio-carpal, and moderate for radio/carpometacarpal measurements. CONCLUSION: In the absence of a strict position control between two imaging acquisitions, only distal radio-ulnar measurements were shown perfectly reliable when using these two imaging methods, which is suggestive of a minor relevance of ulnar/radial deviation. Excepting for some angles, the radio-carpal and radio-carpometacarpal measurements were shown to differ according to wrist position, being thus more sensitive to flexion/extension of the wrist.

Mid-term Outcomes of Treatment of Fracture Dislocation of the Proximal Interphalangeal Joint with Gexfinger®-A New Dynamic External Fixator.

Background: Fracture dislocations of the proximal interphalangeal joint (PIPJ) are challenging injuries and a dynamic external fixator frame is often used. We devised a dynamic external fixator device called the Gexfinger® that allows greater control of the degree of traction. The aim of this study is to report the mid-term outcomes of this device. Methods: This is a retrospective study of patients with fracture dislocation of the PIPJ who were treated with the Gexfinger® over a 3-year period. Clinical data with regard to the patient, the injury, treatment and period of follow-up were recorded. The outcome measures included time to return to work, arc of motion at the interphalangeal joints, grip strength, visual analogue score (VAS) for pain, patient satisfaction and complications. Results: We studied 26 patients (17 men and 9 women) with an average age of 38 years. The average articular surface involvement was 56%. The mean period between injury and surgery was 6 days and the frames were maintained for 5.5 weeks on average. The mean follow-up period was 8.5 weeks. All patients returned to work at an average of 7 weeks. The mean arc of motion at the PIPJ and distal interphalangeal joint (DIPJ) were 82° and 65°, respectively and the mean grip strength was 83% of the contralateral side. 22 patients reported no pain at the final follow-up. Fifteen patients were very satisfied, 8 satisfied and 3 unsatisfied. Two patients had stiffness of the PIPJ. Conclusions: The mid-term outcomes of the Gexfinger® are similar to other methods of dynamic traction described in literature. It is modular, easy to assemble and allows a greater control of the degree of traction. In combination with additional screws and/or K-wires, it has allowed us to treat a wide spectrum of PIPJ fracture dislocations with good outcomes. Level of Evidence: Level IV (Therapeutic).

[Long fingers proximal interphalangeal joint trauma]. / Traumatismes de l'articulation interphalangienne proximale des doigts longs.

Sprains and dislocations of the proximal interphalangeal joint (PIP) are very common but are, nevertheless, often missed. They require an appropriate treatment to prevent stiffness and deformities. Initial assessment should include anteroposterior and true lateral radiographs. Intra-articular fractures are referred to the specialist. Clinical examination to detect laxity is essential and will guide the treatment. The treatment is based on the restoration of joint congruency and achieving early mobilization. Surgical indication is rare. The evolution is slow, pain and joint swelling can persist up to one year and definitive complications are not excluded.

Les entorses et luxations de l'articulation interphalangienne proximale sont très fréquentes, elles sont néanmoins souvent méconnues. Elles doivent être traitées de manière adaptée afin de limiter le risque de raideur et de déformation. Le bilan commence par une radiographie de face et de profil strict afin d'exclure une fracture qui sera adressée directement au spécialiste. Les luxations sont à réduire en anesthésie locale. L'examen clinique à la recherche d'une laxité est primordial et guidera le traitement. L'indication chirurgicale est rare. L'évolution est lente et des douleurs ainsi qu'un œdème articulaire peuvent persister jusqu'à un an. Des séquelles définitives (raideur, déformation et élargissement de l'articulation) ne sont pas exclues.

[Sport wrist ligament injuries]. / Lésions ligamentaires du poignet sportif.

The wrist is a joint structure particularly exposed during sports practice to trauma or overuse. Ligament trauma is particularly common as well as tendinopathies. A rigorous clinical examination is the key to the management of the sports patient. The additional examinations will confirm the diagnosis and help guide the management. The purpose of the treatment in the athlete will depend on his sports activity, his age, the sport, the time between the accident and the sports season.

Le poignet est une structure articulaire particulièrement exposée au traumatisme ou à la surutilisation lors de la pratique sportive. Les traumatismes ligamentaires sont très fréquents ainsi que les tendinopathies. Un examen clinique rigoureux est la clé de la prise en charge du patient sportif. Les examens complémentaires vont confirmer le diagnostic et permettre d'orienter la prise en charge. Le but du traitement chez le sportif va dépendre de son activité sportive, de son âge, du sport, du délai entre l'accident et de la saison de sport en question.

Comparison of simulated key pinch after three surgical procedures for trapeziometacarpal osteoarthritis: a cadaver study.

We performed a cadaver study using 18 fresh-frozen adult forearms and hands to compare the tendon loads required to generate progressively greater key pinch (0.5 kg to 2 kg) after three different surgical procedures to treat trapeziometacarpal osteoarthritis: isolated trapeziectomy, trapeziectomy followed by ligament reconstruction with tendon interposition and total joint arthroplasty using a Touch® implant. Thumb pinch was simulated by loading the main actuator tendons involved in the key pinch. Six specimens were randomly assigned to each of the three surgical procedure groups. Measurements were made before and after the joint surgery. Specimens that underwent trapeziectomy with or without ligament reconstruction with tendon interposition required significantly higher tendon loads than those with the implant to achieve the same pinch force. There was no significant difference between the isolated trapeziectomy and ligament reconstruction groups. Using the implant resulted in similar median tendon loads compared with those of the intact sample. Total joint arthroplasty with a Touch® prosthesis may yield a superior biomechanical profile in which the tendon loads needed to achieve a certain key pinch force are lower and better distributed between the actuator muscles compared with trapeziectomy with or without ligament reconstruction.

Determining diagnosis of scaphoid healing: Comparison of cone beam CT and X-ray after six weeks of immobilization.

PURPOSE: To assess the accuracy and reliability of using cone beam computed tomography (CBCT) compared to X-ray six weeks after injury for predicting scaphoid union. MATERIALS AND METHODS: Overall; 52 patients with scaphoid fractures between April 2018 and March 2019 were prospectively included in this study. The mean age was 34.52 (13-88) years, and the gender ratio male/female 43/9. Of the fractures, 26 had occurred on the right side, and 26 on the left side. In total, 28 % of patients were manual workers. All patients underwent X-ray and CBCT six weeks after injury. Four readers, two radiologists, and two hand surgeons analyzed the findings using double-blinded X-ray and CBCT and categorized fractures as consolidated based on a 50 % visibility threshold concerning trabecular bridges. Proximal pole sclerosis, communition, cyst formation, and humpback deformity were similarly analyzed for all cases. Agreement between readers was calculated using Kappa, and sensitivity, specificity, and accuracy using RStudio software. The gold standard was the radiologic and clinical follow-up for all patients at two months. RESULTS: Inter-reader agreement between the four readers was moderate concerning X-ray (0.543) but substantial concerning CBCT (0.641). It was almost perfect between seniors regarding CBCT (Kappa = 0.862). Sensitivity, specificity, and accuracy were 0.75-0.78, 0.4, and 0.61-0.64, respectively, for two readers regarding CBCT. The X-ray values were 0.65-0.71, 0.35-0.4, and 0.53-0.59, respectively. CONCLUSION: CBCT proves more accurate and reliable than X-ray for diagnosing scaphoid union at an early follow-up and prevents longer immobilization and interruption of activity or work.

[Diagnosis of athlete's elbow injuries]. / Diagnostic des lésions du coude de l'athlète.

The elbow joint is highly congruent and subject to less stress than other joints. This contributes to a rather low incidence of pathologies in the general population. However, in athletes who perform repeated movements with supraphysiological forces, diverse pathologies may appear. The objective of this article is to develop an anatomopathological approach to elbow pain in order to identify its origin. A rapid and precise diagnosis allows initiating an adequate treatment and minimizing time of sporting activity arrest.

L'articulation du coude est soumise à des contraintes mécaniques moindres que d'autres articulations et présente une importante congruence. Ces éléments contribuent à la faible incidence des pathologies qui l'affectent dans l'ensemble de la population. Toutefois, chez le sportif qui effectue des mouvements répétés et avec des forces supraphysiologiques, de multiples lésions peuvent survenir. L'objectif de cet article est de développer une démarche anatomopathologique pour le diagnostic des douleurs de coude. Un diagnostic rapide et précis permet la mise en place d'un traitement adéquat ainsi que de minimiser le temps d'arrêt de l'activité sportive.

[Radiology of the hand and wrist for the general practicioner]. / Radiologie de la main et du poignet pour le médecin de premier recours.

The management of many traumatic conditions of the hand and wrist can be done or at least initiated by the primary care physician, often the first actor of the scenario. To do so, he must first have performed a correct reading of X-rays made with specific incidences to the suspected pathology. This article reviews the radiological diagnosis of the most common pathologies in hand and wrist traumatology to facilitate interpretation by general practitioners.

La prise en charge de nombreuses pathologies traumatiques de la main et du poignet peut s'effectuer ou tout du moins être initiée par les médecins de premier recours (MPR), bien souvent premiers acteurs du scénario. Pour ce faire, le MPR doit au préalable avoir effectué une lecture correcte des radiographies standards réalisées avec des incidences spécifiques à la pathologie suspectée. Cet article rappelle comment interpréter une radiographie standard du poignet et de la main. Les pathologies parmi les plus fréquentes en traumatologie de la main et du poignet sont abordées afin d'en faciliter l'interprétation.

Ultrasound of the ulnar-palmar region of the wrist: normal anatomy and anatomic variations.

Ultrasound (US) assessment of the wrist is frequently used for the evaluation of carpal tunnel due to high frequency of local compression of the median nerve (MN), but the ulnar-palmar wrist region (UPWR) has received limited attention in the medical literature. The possibilities of US in the assessment of UPWR are therefore likely underestimated by sonologists. This review article is focused on the US assessment of the normal anatomy and anatomic variations of the UPWR. The anatomy of this region of the wrist is complex and less studied than the radial side. In an effort to simplify it and to present it didactically, we have divided this region in three parts on the basis of osseous landmarks. Our review indicates sonography is effective in identifying the UPWR and related disorders, and is thus a valuable tool for ensuring appropriate management of a variety of disorders.

Ultrasound of local complications in hand surgery: a pictorial essay.

Early detection of local complications (venipuncture complications, nerve lesions, infections, arthritis, and tenosynovitis, tendon adhesions and re-tears, complications related to orthopaedic hardware) after hand surgery is required for prompt treatment. Ultrasound has proven to be a valuable imaging modality for detecting and assessing a variety of disorders of the wrist and hand. The purpose of this pictorial essay is to present a wide range of complications after wrist and hand surgery assessed by ultrasound.

Carpal Collapse After Scaphoid Nonunion: A Novel Combined Approach to the 1,2 Intercompartmental Supraretinacular Artery Radial Flap.

Purpose: Scaphoid nonunion remains a major problem in hand surgery. The 1,2 intercompartmental supraretinacular artery flap (1,2 ICSRA), as first described by Zaidemberg et al, is widely used with reported union rates of approximately 80%. However, its use is limited in the case of associated carpal collapse as in dorsal intercalated segmental instability (DISI) and humpback deformity. In this study, we present a novel approach to this flap enabling the correction of associated carpal collapse. Methods: Between 2006 and 2015, 9 patients with scaphoid nonunion or delayed union with carpal collapse were treated with a vascularized bone flap based on the 1,2 ICSRA using a combined volar and dorsal approach. Immobilization in a short-arm cast was applied for 8 weeks. Union rates, correction of DISI and humpback deformity, as well as clinical end points were noted. In addition, scapholunate (SL) angles were measured using 2 accepted radiological techniques, employing either the scaphoid midline axis or its proximal radiological landmarks as a reference. Results: All cases united and a median time to bone consolidation of 4 months (range, 2-5 months) was observed. Preoperative DISI deformities (n = 4) were corrected in all patients. Humpback deformities (n = 5) were also corrected. Two patients had repeat surgery: one for K-wire removal after bony consolidation and the other for neuropathic pain. Conclusions: The 1,2 ICSRA bone flap is a reliable treatment for scaphoid nonunion associated with carpal collapse. This combined volar and dorsal approach permits the correction of DISI and humpback deformity without compromising the scaphoid vascular supply, which eliminates the need to use free bone flaps from other sites. In this series, we observed a 100% union rate. Two patients required reoperation for symptomatic hardware and dorsal wrist pain linked to superficial neuritis. Type of study/level of evidence: Therapeutic IV.

Two weeks versus four weeks of antibiotic therapy after surgical drainage for native joint bacterial arthritis: a prospective, randomised, non-inferiority trial.

OBJECTIVE: The optimal duration of postsurgical antibiotic therapy for adult native joint bacterial arthritis remains unknown. METHODS: We conducted a prospective, unblinded, randomised, non-inferiority study comparing either 2 or 4 weeks of antibiotic therapy after surgical drainage of native joint bacterial arthritis in adults. Excluded were implant-related infections, episodes without surgical lavage and episodes with a follow-up of less than 2 months. RESULTS: We enrolled 154 cases: 77 in the 4-week arm and 77 in the 2-week arm. Median length of intravenous antibiotic treatment was 1 and 2 days, respectively. The median number of surgical lavages was 1 in both arms. Recurrence of infection was noted in three patients (2%): 1 in the 2-week arm (99% cure rate) and 2 in the 4-week arm (97% cure rate). There was no difference in the number of adverse events or sequelae between the study arms. Of the overall 154 arthritis cases, 99 concerned the hand and wrist, for which an additional subgroup analysis was performed. In this per-protocol subanalysis, we noted three recurrences: one in the 2-week arm (97 % cure); two in the 4-week arm (96 % cure) and witnessed sequelae in 50% in the 2-week arm versus 55% in the 4-week arm, of which five (13%) and six (13%) needed further interventions. CONCLUSIONS: After initial surgical lavage for septic arthritis, 2 weeks of targeted antibiotic therapy is not inferior to 4 weeks regarding cure rate, adverse events or sequelae and leads to a significantly shorter hospital stay, at least for hand and wrist arthritis. TRIAL REGISTRATION NUMBER: NCT03615781.

High resolution MRI of nail tumors and tumor-like conditions.

Although the nail is a small anatomical structure, it can be affected by various tumors and tumor-like conditions. Because of the distinctive nail anatomy, the clinical presentation of tumors is modified, thus rendering the diagnosis challenging. As nail biopsy and surgery are painful procedures associated with an increased risk of permanent onychodystrophy, pre-operative diagnosis is desirable. Although conventional radiographs are still the first-line radiologic examination for the assessment of bony structures beneath the nail matrix, they do not allow detailed evaluation of the phalangeal soft tissues. High resolution MRI allows accurate detection and mapping of nail lesions and can suggest a specific diagnosis. This review focuses on high resolution MRI of nail tumors and tumor-like lesions. We review the nail anatomy and the optimal MRI protocol. We then discuss a variety of tumors and tumor-like lesions in relation to the clinical presentation, anatomic location, histological features and imaging characteristics. We herewith describe common benign tumors (glomus tumor, onychomatricoma, keratoakanthoma, fibroma, subungual exostosis, hemangioma, chondroma, pyogenic granuloma), malignant tumors (subungual melanoma, subungual squamous cell carcinoma), as well as tumor mimics (mucoid cyst, epidermoid cyst). Although not entirely specific, MRI is a valuable tool in treatment planning of these tumors.