Relationship between first tarsometatarsal ligament morphology and its continuity with the fibularis longus and first tarsometatarsal joint degeneration.

This study explored the relationship between the morphological characteristics of the first tarsometatarsal ligaments and fibularis longus (FL) and the severity of articular cartilage degeneration in the first tarsometatarsal joint. Sixty legs from 30 cadavers were examined. The plantar, dorsal, and medial first tarsometatarsal ligaments were classified by fiber bundle number, and their morphological characteristics (fiber bundle length, width, thickness) were measured. The FL was categorized by its continuity with the plantar first tarsometatarsal ligament (PTML): Type A, connection with the PTML only on the first metatarsal; Type B, connection along the entire PTML; and Type C, no connection with the PTML. The severity of articular cartilage degeneration was assessed in four stages. No significant differences in cartilage degeneration among ligament types were found. Negative correlations were observed between the fiber bundle width and thickness of the PTML and the severity of cartilage degeneration. FL was classified as Type A in 68%, Type B in 27%, and Type C in 5% of feet. The fiber bundle thickness of the PTML in Type B was greater than in other types. Our findings suggest that smaller fiber bundle width and thickness in the PTML may be associated with severe cartilage degeneration. The FL had continuity with the PTML in 95% of feet and could enhance the mechanical strength of the PTML in Type B feet.

Gait and electromyographic alterations due to early onset of injury and eventual rupture of the cranial cruciate ligament in dogs: A pilot study.

OBJECTIVE: Identify relevant electromyography (EMG), kinematic, and kinetic changes resulting from monopolar radiofrequency energy (MRFE)-induced cranial cruciate ligament (CCL) injury and eventual rupture in dogs. STUDY DESIGN: Experimental, repeated measures. ANIMALS: Five purpose-bred female dogs free of orthopedic and neurologic disease. METHODS: Surface EMG, joint kinematics, and ground reaction forces were assessed at a trot in the pelvic limbs at baseline, at 2 and 4 weeks after unilateral MRFE-induced CCL injury, and at 4, 8, and 16 weeks after CCL rupture (CCLR). RESULTS: After MRFE-induced injury, average hip joint range of motion (ROM) during stance decreased within the untreated pelvic limb. After CCLR, stifle flexion angles decreased within the treated limb at 8 weeks and within the untreated pelvic limb at all time points, whereas average tarsal joint ROM decreased in the treated limb and increased in the untreated limb. Peak vertical ground reaction force and impulse decreased within the treated limb. Qualitative alterations of many EMG values were noted after MRFE-induced injury and CCLR, although significant differences between limbs or from baseline values were not detected. CONCLUSION: Monopolar radiofrequency energy-induced injury altered contralateral hip kinematics, suggesting early regional compensatory gait alterations. After CCLR, additional compensatory gait patterns occurred in both pelvic limbs. CLINICAL IMPACT: The qualitative analysis of trial-averaged EMG data in this small population supports a relationship between neuromuscular function and induced CCL injury leading to rupture.

Tarsometatarsal joint communication during fluoroscopy-guided therapeutic joint injections and relationship with patient age and degree of osteoarthritis.

OBJECTIVE: Although the tarsometatarsal joints are separated into three distinct synovial compartments, communications between adjacent compartments are often noted during image-guided injections. This study aims to determine whether abnormal inter-compartment tarsometatarsal joint communication is associated with patient age or degree of tarsometatarsal osteoarthritis. MATERIALS AND METHODS: One hundred forty tarsometatarsal injections were retrospectively reviewed by two radiologists. Extent of inter-compartment communication and degree of osteoarthritis were independently scored. Univariate and multivariable analyses were performed to assess whether the presence of and number of abnormal joint communications were related to age and degree of osteoarthritis. RESULTS: Forty out of 140 tarsometatarsal joints showed abnormal communication with a separate synovial compartment, and 3 of the 40 showed abnormal communication with two separate compartments. On univariate analysis, higher grade osteoarthritis (p < 0.001) and older age (p = 0.014) were associated with an increased likelihood of abnormal inter-compartment tarsometatarsal communication and a greater number of these abnormal communications. On multivariate analysis, the degree of osteoarthritis remained a significant predictor of the presence of (p < 0.001) and number of (p < 0.001) abnormal communications, while the association of age was not statistically significant. There was significant correlation between age and degree of osteoarthritis (p < 0.001). CONCLUSION: Higher grade osteoarthritis increases the likelihood of abnormal inter-compartment tarsometatarsal joint communication and is associated with a greater number of abnormal communications. Diagnostic injection to localize a symptomatic tarsometatarsal joint may be less reliable in the setting of advanced osteoarthritis.

Remodeling of the Calcaneocuboid Joint in the Acquired Flatfoot.

There has been debate recently as to whether the lateral column is actually short in the acquired flatfoot. Doubters argue that it is not possible for the lateral column to change in length and actually shorten, especially in the acquired type. In this series of 21 consecutive patients operated on for an acquired flatfoot, the calcaneocuboid joint (CC) had remodeled in all, resulting in the calcaneal side being short, facing laterally and dorsally. These findings give evidence to the rationale for performing a lateral column lengthening (LCL) proximal to the CC joint to treat the acquired flatfoot. When performing a LCL, one should attempt to restore length to the calcaneal side of the joint and to redirect it medially and plantarward. (Journal of Surgical Orthopaedic Advances 27(3):237-245, 2018).

Therapeutic antibody targeting of indoleamine-2,3-dioxygenase (IDO2) inhibits autoimmune arthritis.

Rheumatoid arthritis (RA) is a debilitating inflammatory autoimmune disease with no known cure. Recently, we identified the immunomodulatory enzyme indoleamine-2,3-dioxygenase 2 (IDO2) as an essential mediator of autoreactive B and T cell responses driving RA. However, therapeutically targeting IDO2 has been challenging given the lack of small molecules that specifically inhibit IDO2 without also affecting the closely related IDO1. In this study, we develop a novel monoclonal antibody (mAb)-based approach to therapeutically target IDO2. Treatment with IDO2-specific mAb alleviated arthritis in two independent preclinical arthritis models, reducing autoreactive T and B cell activation and recapitulating the strong anti-arthritic effect of genetic IDO2 deficiency. Mechanistic investigations identified FcγRIIb as necessary for mAb internalization, allowing targeting of an intracellular antigen traditionally considered inaccessible to mAb therapy. Taken together, our results offer preclinical proof of concept for antibody-mediated targeting of IDO2 as a new therapeutic strategy to treat RA and other autoantibody-mediated diseases.

Arthroscopy of the Dorsal and Plantar Pouches of the Tarsocrural Joint for the Treatment of Osteochondritis Dissecans in the Horse: Clinical Features and Follow-Up.

OBJECTIVE: To describe the clinical details and pathology within the dorsal and plantar pouches of the tarsocrural joint of a population of horses that underwent arthroscopic surgery for tarsocrural osteochondritis dissecans (OCD). STUDY DESIGN: Retrospective cohort study. ANIMALS: Horses referred for arthroscopic treatment of tarsocrural OCD between 2005 and 2013 (102 horses; 144 joints). METHODS: Case records of all horses that had tarsocrural arthroscopy for OCD at Rossdales Equine Hospital, Newmarket, United Kingdom were included. Cases from 3 ECVS Diplomates were included, 1 of whom routinely examined 70 plantar pouches concurrently with routine dorsal pouch investigation. A structured questionnaire was used to obtain follow-up data alongside examination of racing records where appropriate. Descriptive data and 95% CI were calculated. RESULTS: Of the 70 joints that had both dorsal and plantar pouches examined, there was cartilage erosion/degeneration in 22 dorsal pouches (31.4%), cartilage wear lines in 32 plantar pouches (45.7%), and fragments were removed at the time of surgery from 7 plantar pouches (10.0%). Of the plantar pouches with wear lines, 18 (25.7%) had no evidence of cartilage abnormalities (separate from the OCD lesion) within the dorsal pouch. From the 102 horses with available follow-up, 34 horses (66.7%) achieved their intended use postsurgery. CONCLUSION: Routine plantar pouch investigation is warranted in cases of tarsocrural OCD to provide further information on the health of the joint and allows for removal of fragments from the plantar pouch that may not have been identified by routine diagnostic radiography.

Primary synovial chondromatosis of the talonavicular joint: A case report.

Synovial chondromatosis developes by metaplasia of the synovial cells in the synovium of joints, and is a benign synovial tumor with multiple cartilaginous nodules. It is most commonly found in single and large joints, such as the knee, hip, and shoulder. Occurrence in the foot and ankle is uncommon, although there have been previous reports in the orthopedic and radiological literature of primary synovial chondromatosis in the subtalr, calcaneocuboid, naviculocuneiform, and metatarsaophalangeal joints. To our knowledge, occurrence in the talonavicular joint is even rarer, with only one report in the literature to date. Here, we report a case of synovial chondromatosis of the talonavicular joint, alongside a review of the literature.

Effect of nonanimal high- and low-molecular-mass chondroitin sulfates produced by a biotechnological process in an animal model of polyarthritis.

BACKGROUND/AIMS: We planned to report on the effect of two nonanimal chondroitin sulfates (CSs) with different molecular masses produced using an innovative biotechnological process in an adjuvant arthritis animal model. METHODS: The experiments included healthy animals, untreated arthritic animals and arthritic animals having been administered 900 mg/kg of either of the two CS samples daily. Arthritic score, γ-glutamyltransferase (GGT) activity in hind paw joint tissue homogenates, plasmatic C-reactive protein (CRP) and pro-inflammatory cytokines IL-1ß and IL-6 were assayed. RESULTS AND CONCLUSIONS: Low-molecular-mass (LMM) CS significantly reduced the arthritic score by up to about 30% from 14 to 28 days. In contrast, no significant differences were observed for high-molecular-mass (HMM) CS, even if a trend in its capacity to decrease the arthritic score by up to about 11% was observed. Additionally, LMM CS was able to significantly decrease GGT activity by approximately 31% and plasmatic CRP levels by about 9%. Both nonanimal CS samples were effective in reducing plasmatic levels of proinflammatory cytokines. A greater efficacy was also observed for LMM CS compared with a pharmaceutical-grade CS of extractive origin, while the efficacy of the HMM CS sample was found to be rather similar. The greater effect of LMM CS in reducing arthritic parameters may be related to its lower molecular mass with respect to HMM CS and natural CS.

Relationship between joint structure of the first tarsometatarsal joint and its degeneration.

This study aimed to elucidate the relationship between joint structures of the first tarsometatarsal and articular facet degeneration. A total of 100 feet from 50 cadavers were examined. The articular facets of the first metatarsal and medial cuneiform were categorized into four types based on the superior and inferior facets' separation, and the formation of the inferior lateral facet on the lateral plantar prominence: Type I, a single facet with no separation or inferior lateral facet; Type II-a, two facets with separation but no inferior lateral facet; Type II-b, two facets, no separation, but with an inferior lateral facet; Type III, three facets with separation and an inferior lateral facet. When both bone types matched, they were defined as Type I, Type II-a, Type II-b, and Type III joints, respectively; unmatched types were classified as Unpair joints. The severity of articular cartilage degeneration on both bones was assessed using a 5-point scale. The degeneration grade was compared among joint types. Type III joints exhibited significantly milder articular cartilage degeneration in medial cuneiform compared to Type II-a, II-b, Unpair joints. The formation of inferior lateral facet and separation of the superior and inferior facets might be crucial for the joint's stability.

[Regional migrating osteoporosis - a case report]. / Regionální migrující osteoporóza -  diferenciálne dia-gnostický problém.

Regional migrating osteoporosis (RMO) was observed in young man with episodes of bone pain in bearing joints, which migrated from hip to leg and subsequently to knee on the unilateral side. Dynamic scintigraphy (SPECT) carried out during relapse of pain demonstrated increased accumulation of radioizotope in Lisfrank joint, distal epiphysis of femur and proximal epiphysis of tibia on the unilateral side due to hyperperfusion and high metabolic turnover in these regions of the skeleton. Dia-gnosis of RMO was confirmed by magnetic resonance (MRI), which showed bone marrow edema of corresponding regions. Although RMO is relatively benign disease with spontaneous remissions, infection etiology or the more serious avascular necrosis should be taken into account.

Development of osteochondrosis in Lusitano foals: a radiographic study.

This study aimed to detect, by radiographic examination, the evolution of osteochondral lesions in the tarsocrural and femoropatellar joints of Lusitano foals. Within 1 month of age, 76.08% of foals had radiographic signs of osteochondrosis, but only 16.20% had lesions at 18 months. The radiographic signs resolved by 5 mo of age in most foals, but some cases that involved either joint, were not resolved until 12 mo of age. It is thought that the "age of no return" is 5 mo for the tarsocrural and 8 mo for the femoropatellar joint but this study demonstrated regression of osteochondral lesions in both joints of Lusitano foals up to 12 months of age.

Développement de l'ostéochondrose chez les poulains Lusitaniens : une étude radiographique. Cette étude visait à détecter, par examen radiographique, l'évolution des lésions ostéochondrales dans les articulations tarso-crurale et fémoro-patellaire des poulains Lusitaniens. À l'âge de 1 mois, 76,08 % des poulains présentaient des signes radiographiques d'ostéochondrose, mais seulement 16,20 % avaient des lésions à l'âge de 18 mois. Les signes radiographiques se résorbaient à l'âge de 5 mois chez la plupart des poulains, mais, dans certains cas qui touchaient l'une ou l'autre des articulations, ils n'étaient pas résolus jusqu'à l'âge de 12 mois. On croit que l'«âge de non-retour¼ est de 5 mois pour l'articulation tarso-crurale et de 8 mois pour l'articulation fémoro-patellaire, mais cette étude a démontré la régression des lésions ostéochondrales chez les poulains Lusitaniens jusqu'à l'âge de 12 mois.(Traduit par Isabelle Vallières).

Relationship between arthroscopic joint evaluation and the levels of Coll2-1, Coll2-1NO(2), and myeloperoxidase in the blood and synovial fluid of horses affected with osteochondrosis of the tarsocrural joint.

OBJECTIVE: To evaluate the levels of plasmatic and synovial Coll2-1, Coll2-1NO(2) and myeloperoxidase (MPO) in horses with osteochondral lesions of the tarsocrural joint and to investigate how these levels relate to arthroscopic findings of inflammation and degeneration. MATERIALS AND METHODS: Venous blood and synovial fluid samples were collected from 63 horses presented for arthroscopic removal of osteochondral fragments in the tarsocrural joint. Prior to removal of the osteochondral fragment, an exploration of the joint was performed and an inflammatory and degenerative score was determined. The blood and synovial levels of Coll2-1, Coll2-1NO(2) and MPO were also measured. The effects of the arthroscopic evaluation (inflammatory and degenerative classes) on the blood and synovial markers were evaluated using a linear model (GLM procedure), and correlations between biochemical markers in the blood and synovial fluid and the arthroscopic evaluation (inflammatory and degenerative classes) were established (Pearson's correlations). RESULTS: Significantly higher levels of Coll2-1 were detected in synovial fluid of higher degenerative classes. There was a significant correlation between the degenerative score and the synovial levels of Coll2-1 (r=0.27). According to the logistic regression model, there was a significant effect of the degenerative class on synovial levels of Coll2-1. CONCLUSIONS: Coll2-1 correlates well with the degenerative state of tarsocrural joints as evaluated by arthroscopy. This marker can therefore be classified as a burden-of-disease marker in the assessment of joint disease in horses.

Histopathologic features of distal tarsal joint cartilage and subchondral bone in ridden and pasture-exercised horses.

OBJECTIVE: To determine whether histopathologic characteristics of the osteochondral units of equine distal tarsal joints were associated with exercise history in horses without lameness. SAMPLE POPULATION: 30 cadaver tarsi from horses without lameness and with known exercise history were separated into 3 groups: nonridden, pasture exercise (group P); low-intensity, ridden exercise (group L); and high-intensity, elite competition exercise (group E). PROCEDURES: Standardized sites from the centrodistal and tarsometatarsal joints under went histologic preparation. A grading system was adapted to describe location, depth, and shape of lesions; cellular arrangement; organization at cartilage and subchondral bone (SCB) junctions; and organization of SCB. A high score signified a more severe pathological change than a low score. Exercise groups were compared by calculation of Spearman rank correlations. RESULTS: In the centrodistal joint, lesions were present in groups L and E but only medially. Cellular arrangement scores were higher at the dorsomedial location in group P than in groups L and E. Groups L and E had higher scores than group P for the organization of the cartilage, SCB junctions, and SCB, with higher scores at the dorsomedial location. In the tarsometatarsal joint, lesions were evident across the whole joint surface, with more severe lesions located laterally in all 3 groups. Overall, group E had higher scores for cellular arrangement and SCB organization than groups P and L. CONCLUSIONS AND CLINICAL RELEVANCE: Ridden exercise may increase the risk of osteochondral lesions at distal tarsal sites predisposed to osteoarthritis relative to the risk with nonridden exercise.

Association of hindfoot ligament tears and osteochondral lesions.

BACKGROUND: This study aimed to identify the prevalence of ligament and joint surface anatomy variants, ligament tears, and osteochondral lesions (OCLs) in the hindfoot. These data were used to identify associations between anatomic variants or ligament tears and OCLs. METHODS: Seventy-two cadaver hindfoot specimens were examined. Hindfoot ligament presence, number of ligament fascicles, variable ligament attachment sites, ligament tears, presence of joint facets, variable joint surface shape, and the location and grade of OCLs were identified in each specimen. The data were analyzed for significant associations between variables. RESULTS: Fourteen of the 30 studied ligaments were always present and 14 had variable number of fascicles. The lateral talocalcaneal and dorsolateral calcaneocuboid ligaments had varying positional attachments. Osteochondral lesions were present in 86% of specimens with the majority in the talocrural joint. Of the 235 lesions identified, 31 were grade 3 or above. Ligament tears occurred in 2% of all ligaments observed. Tears in the lateral talocalcaneal, medial calcaneocuboid, and dorsolateral calcaneocuboid ligaments were associated with an increased number of hindfoot OCLs. CONCLUSION: We demonstrated the prevalence of morphologic ligament and joint surface variants, ligament tears, and osteochondral lesions in the hindfoot. Tears in ligaments stabilizing the calcaneocuboid joint were implicated in an increase in hindfoot joint damage. CLINICAL RELEVANCE: We believe anatomic studies can be used to clarify the association between traumatic injuries and their sequelae.

Treatment of experimental erosive arthritis in rats by injection of the muralytic enzyme mutanolysin.

A single intravenous injection into rats of 0.4 mg of the muralytic enzyme mutanolysin, given as long as 3 d after an arthropathic dose of peptidoglycan-polysaccharide polymers derived from group A streptococci (PG-APS), resulted in a complete resolution of acute arthritis and the prevention of chronic joint disease. When administration of mutanolysin was delayed until 14 d after the injection of PG-APS, a great reduction in the severity of chronic inflammation was still observed. Quantitation of the amount of PG-APS present in the limbs, spleen, and liver by a solid phase enzyme-linked immunoassay indicated that the tissues of mutanolysin-treated rats contained as much PG-APS as tissues of PBS-treated control rats. In addition, rats treated with mutanolysin immediately after receiving an intraperitoneal injection of PG-APS developed a transient limb edema similar to that seen in rats after the injection of PG-APS digested to a small fragment size in vitro with mutanolysin. We hypothesize that mutanolysin acts in vivo by degrading PG-APS to small fragments that persist but are no longer arthropathic.

Genome-wide association analysis of osteochondrosis of the tibiotarsal joint in Norwegian Standardbred trotters.

Osteochondrosis (OC), a disturbance in the process of endochondral ossification, is by far the most important equine developmental orthopaedic disease and is also common in other domestic animals and humans. The purpose of this study was to identify quantitative trait loci (QTL) associated with osteochondrosis dissecans (OCD) at the intermediate ridge of the distal tibia in Norwegian Standardbred (SB) using the Illumina Equine SNP50 BeadChip whole-genome single-nucleotide polymorphism (SNP) assay. Radiographic data and blood samples were obtained from 464 SB yearlings. Based on the radiographic examination, 162 horses were selected for genotyping; 80 of these were cases with an OCD at the intermediate ridge of the distal tibia, and 82 were controls without any developmental lesions in the joints examined. Genotyped horses descended from 22 sires, and the number of horses in each half-sib group ranged from 3 to 14. The population structure necessitated statistical correction for stratification. When conducting a case-control genome-wide association study (GWAS), mixed-model analyses displayed regions on chromosomes (Equus callabus chromosome - ECA) 5, 10, 27 and 28 that showed moderate evidence of association (P ≤ 5 × 10(-5); this P-value is uncorrected i.e. not adjusted for multiple comparisons) with OCD in the tibiotarsal joint. Two SNPs on ECA10 represent the most significant hits (uncorrected P=1.19 × 10(-5) in the mixed-model). In the basic association (chi-square) test, these SNPs achieved statistical significance with the Bonferroni correction (P=0.038) and were close in the permuted logistic regression test (P=0.054). Putative QTL on ECA 5, 10, 27 and 28 represent interesting areas for future research, validation studies and fine mapping of candidate regions. Results presented here represent the first GWAS of OC in horses using the recently released Illumina Equine SNP50 BeadChip.

IL-33/ST2 induces neutrophil-dependent reactive oxygen species production and mediates gout pain.

Objective: Gout, induced by monosodium urate (MSU) crystal deposition in joint tissues, provokes severe pain and impacts life quality of patients. However, the mechanisms underlying gout pain are still incompletely understood. Methods: We established a mouse gout model by intra-articularly injection of MSU crystals into the ankle joint of wild type and genetic knockout mice. RNA-Sequencing, in vivo molecular imaging, Ca2+ imaging, reactive oxygen species (ROS) generation, neutrophil influx and nocifensive behavioral assays, etc. were used. Results: We found interleukin-33 (IL-33) was among the top up-regulated cytokines in the inflamed ankle. Neutralizing or genetic deletion of IL-33 or its receptor ST2 (suppression of tumorigenicity) significantly ameliorated pain hypersensitivities and inflammation. Mechanistically, IL-33 was largely released from infiltrated macrophages in inflamed ankle upon MSU stimulation. IL-33 promoted neutrophil influx and triggered neutrophil-dependent ROS production via ST2 during gout, which in turn, activated transient receptor potential ankyrin 1 (TRPA1) channel in dorsal root ganglion (DRG) neurons and produced nociception. Further, TRPA1 channel activity was significantly enhanced in DRG neurons that innervate the inflamed ankle via ST2 dependent mechanism, which results in exaggerated nociceptive response to endogenous ROS products during gout. Conclusions: We demonstrated a previous unidentified role of IL-33/ST2 in mediating pain hypersensitivity and inflammation in a mouse gout model through promoting neutrophil-dependent ROS production and TRPA1 channel activation. Targeting IL-33/ST2 may represent a novel therapeutic approach to ameliorate gout pain and inflammation.

Tarsitis as an initial manifestation of juvenile spondyloarthropathy.

OBJECTIVE: The aim of this study was to determine the frequency of tarsitis as one of the first symptoms of juvenile spondyloarthropathy (JSpA) and to analyze whether patients with tarsitis at onset differ from those without it. METHODS: A retrospective chart review was performed, from January 1996 to September 2007, at a paediatric rheumatology unit of a tertiary university hospital. RESULTS: Tarsitis was detected in one-third of the children diagnosed with JSpA. They had fever and received antibiotics due to a suspected infection more frequently than those without tarsitis. Inflammatory low back pain was extremely unusual among these patients. CONCLUSION: There were some differences between children diagnosed with JSpA initially affected with tarsitis and those without it. Patients with tarsitis as one of the first symptoms were often misdiagnosed as soft tissue infections.

Injury to the tarsometatarsal joint complex during fixation of Lisfranc fracture dislocations: an anatomic study.

BACKGROUND: The cause of posttraumatic arthritis in Lisfranc injuries is argued in the literature. The purpose of this study was to determine whether the involved joint surface area increased with repositioning of the guidewire before screw placement. MATERIALS: Nine matched pairs of cadaveric feet were disarticulated at the tibiotalar joint. Under fluoroscopic guidance, cannulated screws were placed over guidewires after a single pass across the joint for right feet and two passes across the joint for left feet. Specimens were disarticulated through the midfoot, and the digital images of the joint surface were evaluated for joint surface area and the surface area of cartilaginous damage resulting from screw placement. RESULTS: Mean injury area for the first metatarsal (MT1) was 0.106 cm2 for one pass and 0.168 cm2 for two passes of the guidewire before screw advancement (p = 0.003) The mean injury area for the second metatarsal (MT2) was 0.123 and 0.178 cm2 for one and two passes, respectively (p = 0.018). Four of nine (44%) of the left foot specimens (2 passes of the guidewire) sustained fractures across the MT2 base and three of those specimens also revealed fractures on the middle cuneiform side of the joint (33%). CONCLUSION: Changing the placement of the guidewire across the midfoot significantly increased the joint surface affected by screw placement. Screws placed plantar to the midline of the joint increased the risk of fracture on both sides of the tarsometatarsal complex.