Anatomy of the Naviculocuneiform Joint Complex.

Background: The purpose of this study was to quantify the articular surfaces of the naviculocuneiform (NC) joint to help clinicians better understand common pathologies observed such as navicular stress fractures and arthrodesis nonunions. Methods: Twenty cadaver NC joints were dissected and the articular cartilage of the navicular, medial, middle, and lateral cuneiforms were quantified by calibrated digital imaging software. Statistical analysis included calculating the mean cartilage surface area dimensions of the distal navicular and proximal cuneiform bones. Length measurements on the navicular were obtained to estimate the geographic location of the interfacet ridges. Lastly, all facets of the articular surfaces were described in regard to the shape and location of cartilaginous or fibrous components. Results were compared using Student t tests. Results: Navicular cartilage was present over 75.4% of the surface area of the proximal NC joint, compared with 72.6% of combined cuneiform cartilage distally. The mean height of the deepest (dorsal-plantar) measurement of navicular articular cartilage was 18 ± 3 mm. The mean heights of the distal medial, middle, and lateral cuneiform articular facets were 15 ± 1 mm, 17 ± 2 mm, and 15 ± 2 mm, respectively. Conclusion: There is significant variation among the articular surfaces of the NC joint. Additionally, the central third of the navicular was calculated to lie in the inter-facet ridge between the medial and middle articular facets of the navicular. Clinical Relevance: Surgeons may consider this study data when performing joint preparation for NC arthrodesis as cartilage was present to a mean depth of 18 mm at the NC joint. Additionally, this study demonstrates that the central third of the navicular, where most navicular stress fractures occur, lies in the interfacet ridge between the medial and middle articular facets of the navicular.

Technique Variation in the Surgical Treatment of Lateral Ankle Instability.

INTRODUCTION: Lateral ankle sprains are the most common type of injury to the ankle and can lead to ankle instability. There are many described techniques for the surgical treatment of lateral ankle instability. The purpose of this study is to quantify the variation in surgeon technique for lateral ankle instability treatment. METHODS: Surveys were sent to 62 orthopaedic foot and ankle surgeons regarding surgical technique for the treatment of lateral ankle instability. Clinical agreement was defined as greater than 80% agreement to assess the cohesiveness of surgical methods as described by Marx et al. Results. Response rate was 49/62 (79%). There was clinical agreement for not using bone tunnels and not using metal anchors. All other factors lacked clinical agreement. A greater average number of throws and knots (4.2 for each, range 1-6 throws, range 2-12 knots) were used by surgeons that do not believe knots cause pain compared to an average of 3.9 (range, 1-6) throws and 4.0 (range, 2-15) knots by surgeons who do believe knots cause pain. The association that surgeon who believed knots do cause pain and thus used fewer knots and throws was not statistically significant (P > .05). The preferred material by surgeons in our study are as follows: nonabsorbable braided suture (26/49, 53%), suture tape (15/49, 31%), and fiber tape (4/49, 8%). Among surgeons who use absorbable suture (34/49, 69%), there was no significant difference (P > .05) between surgeons who believe knots cause pain (23/34, 68%) and those who do not (11/34, 32%). DISCUSSION AND CONCLUSION: Among this small sample of orthopaedic foot and ankle surgeons, there is wide variation in surgical technique for lateral ankle instability treatment and little agreement on the clinical standard of care. This disagreement highlights the need for comparative outcome studies in the treatment of ankle instability. LEVEL OF EVIDENCE: Level III: Retrospective cohort study.

The Foot and Ankle in Ultramarathon Runners: Results of the Ultrarunners Longitudinal TRAcking (ULTRA) Study.

Background: The foot and ankle play a critical role in ultramarathon running. Because foot and ankle injuries are the most common location of injury in this group, proper care is essential for prevention. In this sport, small issues can become big problems over such long distances, and understanding the preventative measures taken by ultramarathon runners may provide insight for other athletes looking to avoid similar problems. The purpose of this study was to examine the routine and preventative care of the foot and ankle, as well as injury rates, in this group of high-risk athletes. Methods: The Ultrarunners Longitudinal TRAcking (ULTRA) Study is the largest known prospective longitudinal study of ultramarathon runners. In this portion of the study, participants reported general health status, running behavior and performance, as well as foot and ankle care, injuries, stretching frequency, and shoewear. Results: A total of 734 ultramarathon runners participated in the study. This group ran a median of 40.2 km per week. Overall, 71.2% of active ultramarathon runners reported a foot or ankle injury in the previous 12 months. The most common injuries reported were plantar fasciitis (36.3%), Achilles tendinitis (24.0%), nonspecific foot pain (14.0%), and stress fractures (13.4%). Sit and reach flexibility test showed that 63.7% of runners could not reach past their toes. There were no significant correlations for sit and reach flexibility or stretching frequency with injury rate. Conclusion: The high prevalence of foot and ankle injuries in ultramarathon runners does not appear to be influenced by arch type, foot strike pattern, orthotic usage, stretching behavior, or actual flexibility. A high percentage of the study runners used comfort as a shoe selection method, independent of alignment or foot strike pattern. These findings guide the clinician in shared decision making with runners about routine care, including injury prevention and shoe selection. Level of Evidence: Level II, prospective study.

Radiographic Measurements of the Foot and Ankle After Ankle Arthrodesis.

Background: Ankle arthrodesis is an established treatment for ankle arthritis. For patients with ankle arthritis, the position of the talus during ankle arthrodesis may affect the radiographic parameters of the foot. The purpose of this study is to assess the radiographic relationship between talar alignment and the longitudinal arch of the foot before and after ankle arthrodesis. Methods: We retrospectively reviewed a single-surgeon series of 30 patients who had undergone ankle arthrodesis. Measured parameters included the lateral tibiotalar angle (LTTA), lateral talometatarsal angle (LTMA), lateral talocalcaneal angle (LTCA), cuneiform height (CH), and calcaneal pitch (CP). Additional data collected included demographics, fusion construct type, and visual analog scale (VAS) measurements. Results: LTTA was increased from 68.2 ± 7.4 degrees preoperatively to 75.0 ± 6.4 degrees postoperatively (P = .001), LTMA increased from -2.0 ± 10.7 degrees to 4.0 ± 10.1 degrees (P < .001), CH increased from 20.1 ± 7.5 mm to 26.1 ± 8.4 mm (P < .001), LTCA and CP had no statistically significant change. VAS score decreased from 5.7 ± 2.7 to 1.3 ± 1.9 (P < .001). Conclusion: Correcting the talar alignment in the sagittal plane during ankle arthrodesis improved the radiographic parameters of the foot, contributing to restoration of the longitudinal arch. The clinical significance of these findings is that in patients undergoing ankle arthrodesis, the surgeon should be aware that the alignment of the foot will be altered at the time of ankle arthrodesis and should be considered in preoperative planning. Further research is needed to determine the effect of ankle arthrodesis in patients determined to have pes planus preoperatively. Level of Evidence: Level III, retrospective cohort study.

Intrinsic muscles of the foot: Anatomy, function, rehabilitation.

The intrinsic muscles of the foot are underappreciated structures in evaluating and treating lower extremity dysfunction. These muscles play a crucial role in the proper function of the foot during sport activities. The functions of these muscles are not generally well understood. Intrinsic dysfunction can lead to a variety of problems. Therefore, it is important for clinicians to have a good understanding of the anatomy and function of the intrinsic foot muscles in order to properly diagnose and treat foot injuries in patients. Published research on the rehabilitation of the intrinsic muscles provides insight into the function as well as benefits of treatment. The purpose of this review is to summarize the published research on the anatomy, function, contribution to pathology, as well as rehabilitation options for the intrinsic muscles of the foot.

Contemporary Review: The Foot and Ankle in Long-Distance Running.

Distance runners represent a unique patient population. The cyclic activity associated with distance running leads to a high incidence of injury. Gait patterns, the extrinsic and intrinsic muscles of the foot and ankle, foot strike pattern, shoe wear considerations, alignment, and orthotics are also all important considerations that must be considered by the treating provider. The purpose of this work is to review relevant functional anatomy, recent studies on gait patterns in running, orthotics, and theory on how the body moves through space during running in order to better equip the clinician to treat long distance runners.

Plantar Plate Repair for Metatarsophalangeal Joint Instability of the Lesser Toes.

The plantar plate is a known stabilizer of the lesser toe metatarsophalangeal (MTP) joint. MTP instability is a known common cause of metatarsalgia, most commonly in the second toe. In the last decade, clinical staging and anatomic grading mechanisms have been published to guide the surgeons on the treatment of MTP instability; this has also led to an understanding of how plantar plate tears relate to MTP joint instability. Direct surgical repair of the plantar plate has been described, short-term outcomes have been published, and the results are not perfect, but promising with respect to patient satisfaction and pain relief.

Articular Cartilage of the Syndesmosis: Avoiding Iatrogenic Cartilage Injury During Syndesmotic Fixation.

BACKGROUND: The optimal surgical management of syndesmosis injuries consists of internal fixation between the distal fibula and tibia. Much of the available data on this joint details the anatomy of the syndesmotic ligaments. Little is published evaluating the distribution of articular cartilage of the syndesmosis, which is of importance to minimize the risk of iatrogenic damage during surgical treatment. The purpose of this study is to describe the articular cartilage of the syndesmosis. METHODS: Twenty cadaveric ankles were dissected to identify the cartilage of the syndesmosis. Digital images of the articular cartilage were taken and measured using calibrated digital imaging software. RESULTS: On the tibial side, distinct articular cartilage extending above the plafond was identified in 19/20 (95%) specimens. The tibial cartilage extended a mean of 6 ± 3 (range, 2-13) mm above the plafond. On the fibular side, 6/20 (30%) specimens demonstrated cartilage proximal to the talar facet, which extended a mean of 24 ± 4 (range, 20-31) mm above the tip of the fibula. The superior extent of the syndesmotic recess was a mean of 10 ± 3 (range, 5-17) mm in height. In all specimens, the syndesmosis cartilage did not extend more than 13 mm proximal to the tibial plafond and the syndesmotic recess did not extend more than 17 mm proximal to the tibial plafond. CONCLUSION: Syndesmosis fixation placed more than 13 mm proximal to the tibial plafond would have safely avoided the articular cartilage in all specimens and the synovial-lined syndesmotic recess in most. CLINICAL RELEVANCE: This study details the articular anatomy of the distal tibiofibular joint and provides measurements that can guide implant placement during syndesmotic fixation to minimize the risk of iatrogenic cartilage damage.

Nitinol, Stainless Steel, and Titanium Kirschner Wire Durability.

Kirschner wires (K wires) are a common fixation device in foot and ankle surgery, particularly in lesser-toe fixation. Fatigue failure is a known complication of this fixation. The material properties of the K wire are a factor in the strength and durability of the wire. The purpose of this study is to compare the durability of K wires made of stainless steel, titanium, and Nitinol. Ten samples each of stainless steel, titanium. and Nitinol underwent cyclic durability testing using a rotating beam approach, and S-N curves (applied stress vs the number of cycles to failure) were generated. The results demonstrate that, generally, Nitinol K wires have a shorter life for the same applied stress than the stainless steel or titanium wires. Titanium had a longer life at low stresses compared with stainless steel, and stainless steel had a longer life at higher stresses. This study provides comparative durability data for K wires made of different metals, which have not been previously reported. Although there was a statistically significant difference in durability for wires used in K wire fixation, all 3 metal types are reasonable choices for temporary K wire fixation.Levels of Evidence: Level 5: Mechanical study.

Anatomy of the Intermetatarsal Facets of the Fourth and Fifth Metatarsals.

BACKGROUND: The intermetatarsal joint between the fourth and fifth metatarsals (4-5 IM) is important in defining fifth metatarsal fractures. The purpose of the current study was to quantify this joint in order to determine the mean cartilage area, the percentage of the articulation that is cartilage, and to give the clinician data to help understand the joint anatomy as it relates to fifth metatarsal fracture classification. METHODS: Twenty cadaver 4-5 IM joints were dissected. Digital images were taken and the articular cartilage was quantified by calibrated digital imaging software. RESULTS: For the lateral fourth proximal intermetatarsal articulation, the mean area of articulation was 188 ± 49 mm2, with 49% of the area composed of articular cartilage. The shape of the articular cartilage had 3 variations: triangular, oval, and square. A triangular variant was the most common (80%, 16 of 20 specimens). For the medial fifth proximal intermetatarsal articulation, the mean area of articulation was 143 ± 30 mm2, with 48% of the joint surface being composed of articular cartilage. The shape of the articular surface was oval or triangular. An oval variant was the most common (75%, 15 of 20 specimens). CONCLUSION: This study supports the notion that the 4-5 IM joint is not completely articular and has both fibrous and cartilaginous components. CLINICAL RELEVANCE: The clinical significance of this study is that it quantifies the articular surface area and shape. This information may be useful in understanding fifth metatarsal fracture extension into the articular surface and to inform implant design and also help guide surgeons intraoperatively in order to minimize articular damage.

First-Tarsometatarsal Joint Alignment After First-Metatarsophalangeal Joint Arthrodesis for Hallux Valgus.

BACKGROUND: Instability of the first-tarsometatarsal (TMT) joint has been proposed as a cause of hallux valgus. Although there is literature demonstrating how first-TMT arthrodesis affects hallux valgus, there is little published on how correction of hallux valgus affects the first-TMT joint alignment. The purpose of this study was to determine if correction of hallux valgus impacts the first-TMT alignment and congruency. Improvement in alignment would provide evidence that hallux valgus contributes to first-TMT instability. Our hypothesis was that correcting hallux valgus angle (HVA) would have no effect on the first-TMT alignment and congruency. METHODS: Radiographs of patients who underwent first-MTP joint arthrodesis for hallux valgus were retrospectively reviewed. The HVA, 1-2 intermetatarsal angle (IMA), first metatarsal-medial cuneiform angle (1MCA), medial cuneiform-first metatarsal angle (MC1A), relative cuneiform slope (RCS), and distal medial cuneiform angle (DMCA) were measured and recorded for all patients preoperatively and postoperatively. RESULTS: Of the 76 feet that met inclusion criteria, radiographic improvements were noted in HVA (23.6 degrees, P < .0001), 1-2 IMA (6.2 degrees, P < .0001), 1MCA (6.4 degrees, P < .0001), MC1A (6.5 degrees, P < .0001), and RCS (3.3 degrees, P = .001) comparing preoperative and postoperative radiographs. There was no difference noted with DMCA measurements (0.5 degrees, P = .53). CONCLUSION: Our findings indicate that the radiographic alignment and subluxation of the first-TMT joint will reduce with isolated treatment of the first-MTP joint. Evidence suggests that change in the HVA can affect radiographic alignment and subluxation of the first-TMT joint. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Incidence of Lower Extremity Injury in the National Football League: 2015 to 2018.

BACKGROUND: Lower extremity injuries are the most common injuries in professional sports and carry a high burden to players and teams in the National Football League (NFL). Injury prevention strategies can be refined by a foundational understanding of the occurrence and effect of these injuries on NFL players. PURPOSE: To determine the incidence of specific lower extremity injuries sustained by NFL players across 4 NFL seasons. STUDY DESIGN: Descriptive epidemiology study. METHODS: This retrospective, observational study included all time-loss lower extremity injuries that occurred during football-related activities during the 2015 through 2018 seasons. Injury data were collected prospectively through a leaguewide electronic health record (EHR) system and linked with NFL game statistics and player participation to calculate injury incidence per season and per 10,000 player-plays for lower extremity injuries overall and for specific injuries. Days lost due to injury were estimated through 2018 for injuries occurring in the 2015 to 2017 seasons. RESULTS: An average of 2006 time-loss lower extremity injuries were reported each season over this 4-year study, representing a 1-season risk of 41% for an NFL player. Incidence was stable from 2015 to 2018, with an estimated total missed time burden each NFL season of approximately 56,700 player-days lost. Most (58.7%) of these injuries occurred during games, with an overall higher rate of injuries observed in preseason compared with regular season (11.5 vs 9.4 injuries per 10,000 player-plays in games). The knee was the most commonly injured lower extremity region (29.3% of lower body injuries), followed by the ankle (22.4%), thigh (17.2%), and foot (9.1%). Hamstring strains were the most common lower extremity injury, followed by lateral ankle sprains, adductor strains, high ankle sprains, and medial collateral ligament tears. CONCLUSION: Lower extremity injuries affect a high number of NFL players, and the incidence did not decrease over the 4 seasons studied. Prevention and rehabilitation protocols for these injuries should continue to be prioritized.

Feasibility of Transosseous Nonarticular Fixation of Lisfranc Injuries.

BACKGROUND: The optimal techniques for Lisfranc open reduction and internal fixation techniques remain debated. The purpose of the current study was to describe the joints involved in Lisfranc fixation and to determine if nonarticular transosseous internal fixation would be possible. METHODS: Twenty cadaver Lisfranc joints were dissected and the articular cartilage was quantified by calibrated digital imaging software. Utilizing CT data, a computational model of the foot was developed and the mean joint surface was mapped and nonarticular screw paths between bones was determined. RESULTS: For the medial-middle cuneiform (C1-C2) connection, 27.3% of the lateral face of C1 and 43.7% of the medial face of C2 was articular cartilage. Three variations of articular morphology were observed on C1 and 2 on C2. From the 3D models, it was determined that a joint-sparing, transosseous screw trajectory was possible between C1 and the second metatarsal and between C1 and C2. These screw paths were large enough to accommodate clinically useful screw diameters (>5 mm). The screw trajectories were roughly perpendicular to the long axis of the foot and take a plantar-medial to dorsal-lateral orientation. CONCLUSION: The articular surface of the Lisfranc joint was quantified for the first time and may be smaller than some surgeons realize. This study demonstrated the orientation required to minimize articular damage. CLINICAL RELEVANCE: The clinical significance of the current study was that a nonarticular screw trajectory was possible, and this information may help guide the placement of these screws.

Synthetic Turf: History, Design, Maintenance, and Athlete Safety.

CONTEXT:: Synthetic turf has become an increasingly common playing surface for athletics and has changed dramatically since its introduction more than 50 years ago. Along with changes to surface design, maintenance needs and recommendations have become more standardized and attentive both to upkeep and player-level factors. In particular, synthetic turf maintenance as it relates to athlete health and safety is an important consideration at all levels of play. EVIDENCE ACQUISITION:: A literature search of MEDLINE and PubMed for publications between the years 1990 and 2018 was conducted. Keywords included s ynthetic turf, artificial turf, field turf, and playing surface. Additionally, expert opinion through systematic interviews and practical implementation were obtained on synthetic turf design and maintenance practices in the National Football League. STUDY DESIGN:: Clinical review. LEVEL OF EVIDENCE:: Level 5. RESULTS:: Synthetic turf has changed considerably since its inception. Playing surface is a critical component of the athletic environment, playing a role both in performance and in athlete safety. There are several important structural considerations of third-generation synthetic turf systems currently used in the United States that rely heavily on strong and consistent maintenance. A common misconception is that synthetic turf is maintenance free; in fact, however, these surfaces require routine maintenance. Whether athletes experience more injuries on synthetic over natural surfaces is also of interest among various levels and types of sport. CONCLUSION:: Modern synthetic turf is far different than when originally introduced. It requires routine maintenance, even at the level of local athletics. It is important for sports medicine personnel to be familiar with playing surface issues as they are often treating athletes at the time of injury and should maintain a level of awareness of contemporary research and practices regarding the relationships between synthetic turf and injury.

The Effect of Pitch Variation and Diameter Variation on Screw Pullout.

Introduction: There are many screw and thread designs commercially available to surgeons for bone fixation. There is a paucity of literature on comparative mechanical properties of various screw and thread designs including variable pitch screws, and tapered screws. This purpose of this study was to test whether varying a screws thread pitch and/or tapering a screws core diameter alters the mechanical performance of screws. Methods: A mechanical pullout test was performed on 4 different screw designs, including a variable pitch screw, a constant pitch screw, and variations of these in a straight and tapered screw design. Three-dimensional printing technology was used to manufacture the metal screws in order to control for as many variables as possible. Results: The pullout strength of the constant pitch screws (304.9 ± 25.3 N, P < .001) was significantly greater than the variable pitch screws (259.7 ± 23.4 N). The pullout strength was also significantly greater for screws with a tapered diameter (305.4 ± 24.1 N) than a constant diameter (259.1 ± 23.5N, P < .001). Tapered diameter variable pitch screws had the largest stiffness overall, which was statistically significant against all other groups (P ⩽ .001). Conclusion: The pullout strength is significantly greater for screws with a tapered diameter than a constant diameter and greater for screws with a constant pitch than for a variable pitch. Results of stiffness testing is mixed depending on the screw taper. The clinical significance of this study is that it provides data on the effects that thread design and tapering have on the pullout strength of screws. Levels of Evidence: Level V: Mechanical study.

Fatigue Bending Strength of Jones Fracture Specific Screw Fixation.

BACKGROUND: Intramedullary screw fixation is a common method of treating proximal metadiaphyseal fifth metatarsal (ie, Jones) fractures. Fatigue failure is a complication of this fixation. There are many screw designs available, including Jones fracture specific fixation, but the optimal choice of screw design is unknown. The purpose of this study was to compare the fatigue strength of Jones fracture specific screw designs as well as other commonly used screw designs. Our hypothesis was that there would be no difference in fatigue strength for Jones fracture specific screw designs at similar screw diameters. METHODS: A study was performed to determine the fatigue bending strength of 5 different screw designs including Jones fracture specific screw designs at 3 different screw diameters. Six screws of each size and design underwent cyclic fatigue testing, and a median fatigue limit (MFL) was determined for each screw design and size. RESULTS: The Stryker Asnis JFX solid 4.0-mm, 5.0-mm, and 6.0-mm screws had a higher MFL than all other screws with similar diameter tested (all P < .0001). Both Jones fracture specific screw designs (Stryker Asnis JFX solid screws and Charlotte Carolina Jones screws) had higher MFLs than the other screw designs tested. CONCLUSION: This study provides comparative fatigue strength data on larger screw diameters, which have not been previously reported. There was a statistically significant difference in screw fatigue properties at the screw diameters tested. CLINICAL RELEVANCE: The clinical significance of this study is that it provides surgeons with fatigue strength data to aid in screw selection for Jones fracture fixation.

Gastrocnemius Contracture in Patients With Rheumatoid Arthritis.

BACKGROUND: Rheumatoid arthritis is a chronic disease affecting multiple joints of the body. More than 90% of patients affected by rheumatoid arthritis develop foot or ankle pain over the course of their disease. The purpose of the current study was to report ankle dorsiflexion in rheumatoid arthritis patients as well as a control group utilizing a validated measurement instrument. METHODS: Using a previously validated device, 70 patients presenting with rheumatoid arthritis and 70 controls were measured for ankle range motion and isolated gastrocnemius contractures. Clinical and goniometer measurement of ankle range of motion was also performed. RESULTS: The rheumatoid arthritis group had a mean dorsiflexion of 12.3 degrees compared to a mean of 17.3 degrees in the control group ( P < .05). The difference in dorsiflexion was significantly less utilizing a goniometer than using the validated device, which may be due to measurement technique and external landmarks ( P < .05). CONCLUSION: Patients with rheumatoid arthritis had less ankle dorsiflexion than the control group. The clinical significance of this study is that it provides evidence that patients with rheumatoid arthritis have decreased ankle dorsiflexion even despite a lack of foot and ankle pain. In light of the high lifetime incidence of foot and ankle pain in these patients, this study provides some evidence that the decreased ankle dorsiflexion may be a contributing factor in foot and ankle pain, but further studies are needed. LEVEL OF EVIDENCE: Level II, prospective cohort study.

Ball and Socket Ankle: Mechanism and Computational Evidence of Concept.

The ball and socket ankle joint is a morphologically abnormal joint characterized by rounding of the articular surface of the talus. Other than anecdotal observation, little evidence has been presented to describe the development of this deformity. The purpose of the present study was to review ankle and subtalar joint mechanics and to kinematically examine the functional combination of these joints as a mechanism of the ball and socket ankle deformity. We reviewed functional representations of the ankle joint, subtalar joint, and ball and socket ankle deformity. A computational study of joint kinematics was then performed using a 3-dimensional model derived from a computed tomography scan of a ball and socket deformity. The joint kinematics were captured by creating a "virtual map" of the combined kinematics of the ankle and subtalar joints in the respective models. The ball and socket ankle deformity produces functionally similar kinematics to a combination of the ankle and subtalar joints. The findings of the present study support the notion that a possible cause of the ball and socket deformity is bony adaptation that compensates for a functional deficit of the ankle and subtalar joints.