A hyperactivating proinflammatory RIPK2 allele associated with early-onset osteoarthritis.

Osteoarthritis (OA) is a common debilitating disease characterized by abnormal remodeling of the cartilage and bone of the articular joint. Ameliorating therapeutics are lacking due to limited understanding of the molecular pathways affecting disease initiation and progression. Notably, although a link between inflammation and overt OA is well established, the role of inflammation as a driver of disease occurrence is highly disputed. We analyzed a family with dominant inheritance of early-onset OA and found that affected individuals harbored a rare variant allele encoding a significant amino acid change (p.Asn104Asp) in the kinase domain of receptor interacting protein kinase 2 (RIPK2), which transduces signals from activated bacterial peptidoglycan sensors through the NF-κB pathway to generate a proinflammatory immune response. Functional analyses of RIPK2 activity in zebrafish embryos indicated that the variant RIPK2104Asp protein is hyperactive in its signaling capacity, with augmented ability to activate the innate immune response and the NF-κB pathway and to promote upregulation of OA-associated genes. Further we show a second allele of RIPK2 linked to an inflammatory disease associated with arthritis also has enhanced activity stimulating the NF-κB pathway. Our studies reveal for the first time the inflammatory response can function as a gatekeeper risk factor for OA.

Hindfoot Arthrodesis with the Blade Plate: Increased Risk of Complications and Nonunion in a Complex Patient Population.

BACKGROUND: Previous hindfoot surgeries present a unique challenge to hindfoot arthrodesis, as the patients may have multiple incisions around the hindfoot. In high-risk patients with compromised soft tissues, a posterior approach can provide an alternative for a fresh soft tissue plane for the surgery. The use of a blade plate construct is widely accepted; however, there are limited data supporting the use of a posterior approach. QUESTIONS/PURPOSES: We asked (1) what proportion of patients treated with this technique achieved osseous union; (2) what complications were observed; (3) were any patient-demographic or health-related factors associated with the likelihood that a patient would have a complication develop? METHODS: Between December 2001 and July 2014, 42 patients received a posterior blade plate. During the period in question, indications for hindfoot arthrodesis using posterior blade fixation were subtalar osteoarthritis below an ankle fusion, malunion or nonunion, failed tibiotalocalcaneal arthrodesis attributable to nonunion of the tibiotalar and/or subtalar joint; or tibiotalar and subtalar osteoarthritis in patients with impaired bone or soft tissue quality (particularly if the soft tissue problem was anterior). During that period, all patients who met those indications were treated with a posterior blade plate. Forty (95%) were included in this study, and two were lost to followup before the 1-year minimum required by the study. Demographics (age, gender, BMI, smoking status, and comorbidities) and surgical data (indication, previous treatment, and additional procedures) were analyzed. Of the 40 patients included, 27 (68%) were male and 13 (33%) were female, with a median of two previous hindfoot or ankle surgeries (range, 0-9 surgeries). The mean age of the patients was 56 ± 13 years. Followup averaged 47 ± 28 months (range, 14-137 months). Twenty-eight of 40 (70%) patients had a tibiotalocalcaneal arthrodesis as a primary (n = 6), primary staged (n = 10), revision (n = 9), or revision staged (n = 3) procedure. Eleven of 40 patients (28%) underwent ankle arthrodesis (primary n = 7, revision n = 4). One of the 40 patients (3%) underwent tibiotalocalcaneal arthrodesis for a failed total ankle arthroplasty. Weightbearing radiographs were used to assess fusion. Osseous fusion was defined as visible trabecular bridging on the lateral and AP ankle views within 6 postoperative months. Delayed union was defined as osseous fusion occurring between 6 and 12 months. Nonunion was defined as no visible trabecular bridging at the latest followup (longer than 12 months). Clinic and surgery notes were reviewed for complications. Univariate analysis was performed to compare patient groups: patients with solid union versus nonunion, and patients with versus without complications. RESULTS: Twenty-nine of 40 (73%) patients had osseous fusion within 6 postoperative months. Four of 40 (10%) patients had a delayed union between 6 and 12 months, and seven of the 40 (18%) patients had nonunions, which occurred in the ankle (n = 3), subtalar (n = 3), or both (n = 1) joints. There were 26 complications observed: 18 (69%) were considered major and eight (31%) were minor. With the numbers available, we did not identify any demographic or surgical factors associated with complications, delayed union, or nonunion. CONCLUSIONS: The proportion of patients treated with a posterior blade plate hindfoot fusion who had delayed union or nonunion is greater than that reported for patients in other series who underwent primary hindfoot arthrodesis with other approaches, and the proportion of patients who had complications develop is high. Further studies are needed to address alternative approaches to achieve hindfoot fusion in patients with complex hindfoot problems. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Arthroscopic Talar Dome Access Using a Standard Versus Wire-Based Traction Method for Ankle Joint Distraction.

PURPOSE: To evaluate the accessibility of the talar dome through anterior and posterior portals for ankle arthroscopy with the standard noninvasive distraction versus wire-based longitudinal distraction using a tensioned wire placed transversely through the calcaneal tuberosity. METHODS: Seven matched pairs of thigh-to-foot specimens underwent ankle arthroscopy with 1 of 2 methods of distraction: a standard noninvasive strapping technique or a calcaneal tuberosity wire-based technique. The order of the arthroscopic approach and use of a distraction method was randomly determined. The areas accessed from both 2-portal anterior and 2-portal posterior approaches were determined by using a molded translucent grid. RESULTS: The mean talar surface accessible by anterior ankle arthroscopy was comparable with noninvasive versus calcaneal wire distraction with 57.8% ± 17.2% (range, 32.9% to 75.7%) versus 61.5% ± 15.2% (range, 38.5% to 79.1%) of the talar dome, respectively (P = .590). The use of calcaneal wire distraction significantly improved posterior talar dome accessibility compared with noninvasive distraction, with 56.4% ± 20.0% (range, 14.4% to 78.0%) versus 39.8% ± 14.9% (range, 20.0% to 57.6%) of the talar dome, respectively (P = .031). CONCLUSIONS: Under the conditions studied, our cadaveric model showed equivalent talar dome access with 2-portal anterior arthroscopy of calcaneal wire-based distraction versus noninvasive strap distraction, but improved access for 2-portal posterior arthroscopy with calcaneal wire-based distraction versus noninvasive strap distraction. CLINICAL RELEVANCE: The posterior 40% of the talar dome is difficult to access via anterior ankle arthroscopy. Posterior calcaneal tuberosity wire-based longitudinal distraction improved arthroscopic access to the centro-posterior talar dome with a posterior arthroscopic approach.

New paradigm for patient-reported outcomes assessment in foot & ankle research: computerized adaptive testing.

BACKGROUND: Accurately measuring, reporting and comparing outcomes is essential for improving health care delivery. Current challenges with available health status scales include patient fatigue, floor/ceiling effects and validity/reliability. METHODS: This study compared Patient Reported Outcomes Measurement Information System (PROMIS)-based Lower Extremity Physical Function Computerized Adaptive Test (LE CAT) and two legacy scales -the Foot and Function Index (FFI) and the sport module from the Foot and Ankle Ability Measure (spFAAM) -for 287 patients scheduled for elective foot and ankle surgery. We documented the time required by patients to complete the instrument, instrument precision, and the extent to which each instrument covered the full range of physical functioning across the patient sample. RESULTS: Average time of test administration: 66 seconds for LE CAT, 130 seconds for spFAAM and 239 seconds for FFI. All three instruments were fairly precise at intermediate physical functioning levels (i.e., Standard Error of Measurement < 0.35), were relatively less precise at the higher trait levels and the LE CAT maintained precision in the lower range while the spFAAM and FFI's had decreased precision. The LE CAT had less floor/ceiling effects than the FFI and the spFAAM. CONCLUSION: The LE CAT showed considerable advantage compared to legacy scales for measuring patient-reported outcomes in orthopaedic patients with foot and ankle problems. CLINICAL RELEVANCE: A paradigm shift to broader use of PROMIS-based CATs should be considered to improve precision and reduce patient burden with patient-reported outcome measuremen foot and ankle patients.

Avoiding Fifth Metatarsal Intramedullary Screw Head Cuboid Impingement: A Weightbearing Computed Tomography Anatomic Study.

BACKGROUND: Multiple case reports of fifth metatarsal (MT) intramedullary fixation highlight symptomatic hardware with screw head impingement on the cuboid. We developed a fifth MT intramedullary screw trajectory model using weightbearing computed tomography data. The goal was to assess for cuboid impingement with simulated intramedullary screw position. METHODS: For 20 weightbearing foot computed tomographs (CTs), an automated tool was used to simulate fifth MT screw fixation in the ideal trajectory down the shaft and with a 7-mm screw head. (1) The closest distance from the simulated ideal trajectory to the cuboid in 3 dimensions was measured. A measurement less than 3.5 mm (the radius of the screw head) indicated screw head impingement on the cuboid if not countersunk into the metatarsal. (2) In 3 dimensions, a simulated screw head was then advanced from the proximal tip of the metatarsal distally into the metatarsal until it was entirely avoiding the cuboid. RESULTS: In this model, 95% (19/20) of the patients would have cuboid impingement if the screw was not countersunk. The average ideal pin start distance was 0.15 mm (SD 2.4 mm) inside the cuboid. In this cohort, the screw head would have to be countersunk an average of 8.1 mm (SD 2.7 mm) relative to the proximal tip of the metatarsal to avoid cuboid impingement. For all cases, the simulated fluoroscopic oblique view was a reliable indicator of cuboid impingement, demonstrating visible overlapping of the screw with the cuboid. The overlap resolved on the oblique foot view once the screw was sufficiently countersunk, confirmed on 3-dimensional imaging. CONCLUSION: The ideal guidewire placement for fifth MT intramedullary fixation is directly against the cuboid. Approximately 95% of patients would have cuboid impingement if the screw is not countersunk. The oblique fluoroscopic view of the foot is a reliable assessment of screw head impingement on the cuboid. LEVEL OF EVIDENCE: Level III, retrospective study.

A biomechanical analysis of a tensioned suture device in the fixation of the ligamentous Lisfranc injury.

BACKGROUND: We hypothesized that using a cadaveric Lisfranc ligamentous injury model, abduction stress would provoke greater post-injury motion than axial weightbearing between the medial cuneiform (MC1) and the base of the second metatarsal (MT2). Second, we hypothesized that both a tensioned suture-button device and a rigid screw fixation method could maintain a reduction and similarly restrain motion to intact (pre-injury) levels. MATERIALS AND METHODS: Motion was measured between MC1 and MT2 in five matched pairs of human cadaveric feet. Specimens were tested prior to injury, following a transverse ligamentous Lisfranc injury, and then randomized to either screw or tensioned suture-button fixation. Axial then abduction loads were applied. Measurements were repeated after one thousand loading cycles. RESULTS: With both axial and abduction loads, statistically significant differences in motion were detected between the intact and post-injury conditions, although the magnitudes were greater with abduction (6.8 mm versus 2.0 mm, p = 0.000004). With abduction loads, both fixation methods were effective in restraining motion to pre-injury levels (screw fixation: 1.5 mm intact versus 1.1 mm post-fixation, p = 0.487; suture-button fixation: 1.3 mm intact versus 2.1 mm post-fixation, p = 0.063), and similarly, both devices restrained motion to less than post-injury levels (screw fixation: 8.1 mm post-injury versus 1.1 mm post-fixation, p = 0.001; suture-button fixation: mean 5.5 mm post-injury versus 2.1 mm post-fixation, p = 0.0002). No significant differences in these patterns were detected following cyclic loading. CONCLUSION: Small, though statistically significant, amounts of motion are produced between MC1 and MT2 with axial loading after a ligamentous Lisfranc injury. With abduction stress, we were able to show a significantly greater difference between pre- and post-injury motion and the ability of both fixation methods to restrain motion to pre-injury levels. CLINICAL RELEVANCE: Abduction stress may be valuable when diagnosing and testing the transverse ligamentous Lisfranc injury. Both suture-button and screw fixation methods restrain motion at the Lisfranc complex.

Deltoid ligament abnormalities in chronic lateral ankle instability.

BACKGROUND: Treatment of patients with repeated ankle sprains and chronic lateral ankle instability tends to focus on the lateral collateral ligaments. We reviewed records to ascertain the prevalence of abnormalities of the deltoid ligament in this population. METHODS: Retrospective review of MR images and surgical reports was performed for all patients during a 3-year period that underwent surgical treatment of chronic ankle instability at a single institution. Forty-seven ankles (46 patients) met inclusion criteria. None had medial ankle pain. RESULTS: On MRI, all patients had anterior talofibular ligament tear, plus injury to one or more additional ligaments. Ninety-one percent had injury of calcaneofibular ligament. Injury to the posterior talofibular ligament was less common (49%). Deltoid ligament injuries were seen in 72% of cases (23% superficial deltoid only, 6% deep deltoid only, 43% both superficial and deep components). Of patients with injury to the superficial deltoid, 32% had an intact deep deltoid ligament. MRI correlated well to surgical findings. CONCLUSION: Deltoid ligament injuries were common in patients with lateral ankle instability who underwent reconstruction.

Minimally invasive distraction technique for prone posterior ankle and subtalar arthroscopy.

BACKGROUND: Prone ankle and subtalar arthroscopy is challenging in part due to the limited working space in these joints. MATERIALS AND METHODS: Fourteen patients undergoing prone posterior arthroscopy with a novel skeletal traction method were reviewed and the technique detailed. RESULTS: No complications were observed in 14 patients treated with a minimally invasive skeletal traction technique for prone ankle and subtalar arthroscopy and 38 patients treated with the same traction device during supine ankle arthroscopy. CONCLUSION: Minimally invasive skeletal traction can be used safely for prone posterior ankle and subtalar arthroscopy.

Charcot-Marie-Tooth disease and the cavovarus foot.

This article focuses on the cavovarus foot shape, with particular emphasis on those patients who have Charcot-Marie-Tooth disease. Recent greater understanding of this deformity has led to a better appreciation of how the underlying condition drives deformity progression and treatment of the problems associated with it. The basic science underpinning the development of Charcot-Marie-Tooth disease is reviewed and some elements of the importance of the genetic variability are emphasized. The mechanics of the development of the cavovarus foot deformity in patients who have this neuromuscular condition are reviewed and the evaluation of such patients is described. The surgical options for treatment are reviewed and the outcomes of studies relevant to surgical planning for this patient population are summarized.

Influence of tendon transfer site on moment arms of the flexor digitorum longus muscle.

BACKGROUND: Adult acquired flatfoot is a common condition that leads to significant morbidity. Along with bony procedures to operatively treat this condition, transfer of the flexor digitorum longus (FDL) tendon to the medial cuneiform or navicular is routinely performed. The goal of this tendon transfer is to increase the capacity of the FDL to invert the hindfoot and control the transverse tarsal joints. However, it is not known whether this biomechanical goal is met or whether one transfer site produces a larger mechanical advantage compared to another site. The purpose of this study was to calculate FDL muscle moment arms at the hindfoot with two clinically relevant transfer locations to quantify the change in mechanical advantage of the FDL after tendon transfer. METHODS: In seven cadaver specimens, muscle moment arms of the FDL with respect to hindfoot motion were measured using the tendon excursion method before and after the FDL was transferred to the plantar aspect of the navicular and medial cuneiform. The position and orientation of the foot and excursion of the FDL tendon were measured with an optoelectronic measurement system. RESULTS: The FDL moment arm did not increase after tendon transfer to either the medial cuneiform or navicular when compared to its native site. There were significant decreases in FDL moment arm when transferred from its native site to the medial cuneiform (56% decrease, p=0.018) and navicular (46% decrease, p=0.026). CONCLUSIONS: In contrast to the clinical proposition that FDL transfer to the navicular or medial cuneiform increases this muscle's mechanical advantage to invert the hindfoot, this cadaver study suggests that, to the contrary, FDL muscle moment arms decrease after tendon transfer.

Outpatient management of continuous peripheral nerve catheters placed using ultrasound guidance: an experience in 620 patients.

BACKGROUND: Continuous peripheral nerve block (CPNB) is an optimal choice for analgesia after orthopedic procedures, but is not commonly used in outpatients because of concern regarding the possibility of catheter-related complications. In addition, it may be difficult to provide adequate patient access to physicians in this setting. We present 620 outpatients who were treated with CPNB using an established protocol. METHODS: All catheters were placed using direct ultrasound visualization. These patients received extensive oral and written preoperative instruction and were provided continuous telephone access to the anesthesiologist during the postoperative period. All patients were also contacted at home by telephone on the first postoperative day. In addition, each patient was seen and examined by the surgeon within 2 wk of hospital discharge. RESULTS: Of the 620 patients, there were 190 interscalene (brachial plexus), 206 fascia iliaca (femoral nerve), and 224 popliteal fossa (sciatic nerve) catheters. Two patients (0.3%) had complications related to the nerve block. In both of these patients, the symptoms resolved within 6 wk of surgery. Twenty-six patients (4.2%) required postoperative interventions by the anesthesiologist. One patient returned to the hospital for catheter removal. CONCLUSIONS: In this large series of outpatients treated with CPNB, there were surprisingly few interventions requiring an anesthesiologist. Likewise, patients were able to manage and remove their catheters at home without additional follow-up. This suggests that with adequate instruction and telephone access to health care providers, patients are comfortable with managing and removing CPNB catheters at home.

Postoperative complications of posterior ankle and hindfoot arthroscopy.

BACKGROUND: Posterior ankle and hindfoot arthroscopy, performed with use of posteromedial and posterolateral portals with the patient in the prone position, has been utilized for the treatment of various disorders. However, there is limited literature addressing the postoperative complications of this procedure. In this study, the postoperative complications in patients treated with posterior ankle and hindfoot arthroscopy were analyzed to determine the type, rate, and severity of complications. METHODS: The study included 189 ankles in 186 patients (eighty-two male and 104 female; mean age, 37.1 ± 16.4 years). The minimum duration of follow-up was six months, and the mean was 17 ± 13 months. The most common preoperative intra-articular diagnoses were subtalar osteoarthritis (forty-six ankles), an osteochondral lesion of the talus (forty-two), posterior ankle impingement (thirty-four), ankle osteoarthritis (twenty), and subtalar coalition (five). The most common extra-articular diagnoses were painful os trigonum (forty-six), flexor hallucis longus tendinitis (thirty-two), and insertional Achilles tendinitis (five). RESULTS: The most common intra-articular procedures were osteochondral lesion debridement (forty-four ankles), subtalar debridement (thirty-eight), subtalar fusion (thirty-three), ankle debridement (thirty), and partial talectomy (nine). The most common extra-articular procedures were os trigonum excision (forty-eight), tenolysis of the flexor hallucis longus tendon (thirty-eight), and endoscopic partial calcanectomy (five). Complications were noted following sixteen procedures (8.5%); four patients had plantar numbness, three had sural nerve dysesthesia, four had Achilles tendon tightness, two had complex regional pain syndrome, two had an infection, and one had a cyst at the posteromedial portal. One case of plantar numbness and one case of sural nerve dysesthesia failed to resolve. CONCLUSIONS: Our experience demonstrated that posterior ankle and hindfoot arthroscopy can be performed with a low rate of major postoperative complications.

Posterior Ankle and Hindfoot Arthroscopy.

INTRODUCTION: Posterior ankle and hindfoot arthroscopy, performed with use of posteromedial and posterolateral portals with the patient in the prone position, has become an important diagnostic and therapeutic procedure for various intra-articular and extra-articular disorders. STEP 1 POSITION THE PATIENT PRONE: If you are planning to use fluoroscopy for surgery and wire distraction, position the patient prone, flex the contralateral knee, and wrap the contralateral leg to a padded holder. STEP 2 APPLY DISTRACTION IF NECESSARY: Invasive distraction is used primarily to improve access to the ankle and subtalar joints. STEP 3 PLACE THE POSTEROLATERAL AND POSTEROMEDIAL PORTALS UNDER FLUOROSCOPIC GUIDANCE: Using a mini-c-arm fluoroscopy unit to guide portal placement, place the posterolateral and posteromedial portals just lateral and medial to the Achilles tendon. STEP 4 PERFORM THE INTRA-ARTICULAR AND/OR EXTRA-ARTICULAR PROCEDURE: Specific procedures include posterior arthroscopic arthrodesis of the subtalar joint, ankle arthrodesis, and excision of the os trigonum with tenolysis of the flexor hallucis longus tendon. STEP 5 CLOSE THE ARTHROSCOPY PORTALS: Close the skin incision with nonabsorbable nylon sutures, and apply a sterile bulky dressing. STEP 6 POSTOPERATIVE CARE: Postoperatively, a plaster splint or walking boot with the foot in neutral is used for the first five to seven days. RESULTS: Posterior ankle and hindfoot arthroscopy was performed in 189 ankles (186 consecutive patients with a mean age of 37.1 years). WHAT TO WATCH FOR: IndicationsContraindicationsPitfalls & Challenges.

Micro-CT Density Analysis of the Medial Wall of the Human Medial Cuneiform.

The human medial cuneiform is incompletely characterized with regard to anatomical morphology, including mineral density and bone quality. Clinically, we have observed failures of fixation by pull-through of devices through relatively soft medial bone. Defining patterns of relative density may provide valuable information regarding implant placement as higher cortical density bone may offer better resistance to such failures. We sought to identify an area of greatest density along the medial wall of the medial cuneiform.Ten fresh-frozen human cadaveric medial cuneiforms underwent micro-computed tomography imaging. Images were analyzed to obtain densities in 4 quadrants along the medial wall of the medial cuneiform. Seven of 10 specimens revealed a maximum density in the plantar distal quadrant of the medial wall of the medial cuneiform. Chi-square goodness-of-fit testing indicated that the density of this quadrant was significantly different from 3 other quadrants (P<.009). Using the Principle of Standard Residuals, the density of the plantar distal quadrant was significantly different than the other 3.We conclude that the plantar distal quadrant of the medial cuneiform contains bone of maximal density when compared to 3 other quadrants. Surgeons who place implants in this region should be aware that this area might offer better resistance to fixation failure.

Lower Extremity Assessment Project (LEAP)--the best available evidence on limb-threatening lower extremity trauma.

Lower Extremity Assessment Project (LEAP) study set out to answer many of the questions surrounding the decision of whether to amputate or salvage limbs in the setting of severe lower extremity trauma. A National Institutes of Health-funded, multicenter, prospective observational study, the LEAP study represented a milestone in orthopedic trauma research, and perhaps in orthopedics. The LEAP study attempted to define the characteristics of the individuals who sustained these injuries, the characteristics of their environment, the variables of the physical aspects of their injury, the secondary medical and mental conditions that arose from their injury and treatment, their ultimate functional status, and their general health. In the realm of evidence-based medicine, the LEAP studies provided a wealth of data, but still failed to completely determine treatment at the onset of severe lower extremity trauma.