Oxidized Zirconium Versus Cobalt Chromium for Primary TKA: No Difference in Midterm Revision Rates From the American Joint Replacement Registry.

BACKGROUND: Cobalt chromium (CoCr) is the most commonly used material in TKA; however, the use of oxidized zirconium (OxZr) implants has increased. The advantages to this material demonstrated in basic science studies have not been borne out in clinical studies to date. QUESTION/PURPOSE: In the setting of the American Joint Replacement Registry (AJRR), how do revision rates differ between CoCr and OxZr after primary TKA? METHODS: The AJRR was accessed for all primary TKAs performed between 2012 and 2020 for osteoarthritis, resulting in 441,605 procedures (68,506 with OxZr and 373,099 with CoCr). The AJRR is the largest joint replacement registry worldwide and collects procedure-specific details, making it ideal for large-scale comparisons of implant materials in the United States. Competing risk survival analyses were used to evaluate the all-cause revision rates of primary TKAs, comparing CoCr and OxZr implants. Data from the Centers for Medicare and Medicaid Services claims from 2012 to 2017 were also cross-referenced to capture additional revisions from other institutions. Revision rates were tabulated and subclassified by indication. Multivariate Cox regression was used to account for confounding variables such as age, gender, region, and hospital size. RESULTS: After controlling for confounding variables, there were no differences between the OxZr and CoCr groups in terms of the rate of all-cause revision at a mean follow-up of 46 ± 23 months and 44 ± 24 months for CoCr and OxZr implants, respectively (hazard ratio 1.055 [95% confidence interval 0.979 to 1.137]; p = 0.16) The univariate analysis demonstrated increased rates of revisions for pain and instability in the OxZr group (p = 0.003 and p < 0.001, respectively). CONCLUSION: These findings suggest there is no difference in all-cause revision between OxZr and CoCr implants in the short-term to mid-term. However, further long-term in vivo studies are needed to monitor the safety and all-cause revision rate of OxZr implants compared with those of CoCr implants. OxZr implants may be favorable in patients who have sensitivity to metal. Despite similar short-term to mid-term all-cause revision rates to CoCr implants, because of the limitations of this study, definitive recommendations for or against the use of OxZr cannot be made. LEVEL OF EVIDENCE: Level III, therapeutic study.

No false elevation in ankle brachial index in patients with tibial plateau fractures and vascular risk factors.

Objectives: The ankle brachial index (ABI) is a useful tool in detection of lower extremity vascular injury. However, diabetes mellitus (DM), chronic kidney disease (CKD), and peripheral vascular disease (PVD) may affect extremity perfusion leading to possible false elevation of the ABI value. If true in trauma patients, this can affect initial evaluation, diagnostics, and management. We therefore explored mean ABI values in tibial plateau fractures of patients with vascular risk factors to help determine whether there is a difference. Design: This is a retrospective chart review of patients sustaining tibial plateau fractures with a specific ABI value recorded in the medical record. Patients were identified as either having vascular risk factors or not and data analysis performed to determine if their ABI differed and whether they were more likely to have a vascular injury. Results: 282 acute tibial plateau injuries with specific ABI values were identified, 46 of which carried the risk factors in question. The average risk factor group ABI was 0.95 ±â€¯0.15 versus those without risk factors 1.0 ±â€¯0.15 (p = 0.057). No patient with risk factors required a vascular intervention or four-compartment fasciotomy. Conclusions: This study shows no statistical significance between the presenting ABI of patients with risk factors such as DM, CKD, or PVD and those without those risk factors who sustained acute tibial plateau fractures. Therefore, in general the ABI still holds as a useful screening tool for evaluation of vascular insult in the setting of acute lower extremity trauma.

Contributions of Pubic Rami Fracture Morphology and Fixation to Pelvic Ring Stability in Type 1 Lateral Compression Injuries: A Biomechanical Cadaveric Study.

BACKGROUND: Treatment of lateral compression type 1 (LC-1) injuries has historically been nonoperative with immediate weight-bearing. However, management of these injuries remains controversial, with reports of displacement at follow-up for nonoperatively managed LC-1 fractures. The goal of our study was to determine the effect of superior pubic ramus fracture morphology and fixation construct on pelvic stability. METHODS: Ten fresh-frozen cadaveric were transected into hemi-pelvises. Incomplete Denis type 1 sacral fractures were made. Hemi-pelvises were randomized to receive a transverse-type or oblique-type superior pubic ramus fracture with the contralateral hemi-pelvis receiving the opposing morphology. A lateral load to 135N was applied with an Instron materials testing machine and lateral displacement of the hemi-pelvis was recorded. Deflection and stiffness were calculated. Statistical analysis was conducted using a t test assuming unequal variances with an alpha = 0.05. RESULTS: Oblique-type superior pubic ramus fractures allowed more deflection compared with transverse-type fractures in the absence of fixation (P = 0.018). The posterior-only and combined anterior and posterior fixation configurations on average reduced deflection more than no fixation or anterior fixation only. In all fixation configuration cases, the average deflection for transverse-type fractures was less than that of the oblique-type fractures. CONCLUSIONS: Our findings suggest that displacement of LC-1 pelvic injuries may be related to pubic rami fracture morphology. When looking at initial injury imaging, oblique-type pubic rami fractures may suggest an increased potential for displacement over time. In such cases, we recommend an examination under anesthesia to evaluate for underlying instability and consideration for fixation. LEVEL OF EVIDENCE: Therapeutic Level V.

Staged salvage of diabetic foot with Chopart amputation and intramedullary nailing.

We present a stepwise surgical approach that can be used, in lieu of a transtibial amputation, to preserve the lower limb in the setting of severe diabetic foot infections. A 63-year-old male status post left midfoot (Lisfranc's) amputation presented to our hospital with a 4-year history of a left foot diabetic ulcer with associated purulent drainage and intermittent chills. On initial exam, the patient's left foot amputation stump was plantarflexed, grossly erythematous, and edematous. The associated diabetic foot ulcer was actively draining purulent fluid. Following workup with radiography and ultrasound, the patient was diagnosed with a post-operative infection of the midfoot at the level of the amputation stump secondary to diabetic neuropathy. Our approach to management was a staged and included (1) surgical irrigation and debridement of the distal stump wound, (2) provisional negative pressure therapy, (3) a second-look procedure, and (4) a tibiotalocalcaneal fusion was performed using a lateral transfibular and plantar approach, after wound closure and resolution of active infection was achieved. At 36-month follow-up, the patient was fully weight-bearing in stiff sole sneakers with no gross overt alteration of gait pattern. The patient scored 79 points when assessed by the hindfoot American Orthopaedic Foot and Ankle Society Ankle-Hindfoot outcome score. In the patient with diabetes and cardiological restrictions, a Chopart amputation is preferred due to the decreased level of energy expenditure required for ambulation as compared to over more proximal levels of amputation.

Ulnar nerve subluxation and dislocation: a review of the literature.

The pathogenesis of ulnar nerve subluxation and dislocation is widely debated. Upon elbow flexion, the ulnar nerve slips out of the groove for the ulnar nerve, relocates medial or anterior to the medial epicondyle, and returns to its correct anatomical position upon extension. This chronic condition can cause neuritis or neuropathy; however, it has also been suggested that it protects against neuropathy by reducing tension along the nerve. This article reviews the extant literature with the aim of bringing knowledge of the topic into perspective and standardizing terminology.

Multiplanar Semiautomatic Assessment of Foot and Ankle Offset in Adult Acquired Flatfoot Deformity.

BACKGROUND: Semiautomatic 3-dimensional (3D) biometric weightbearing computed tomography (WBCT) tools have been shown to adequately demonstrate the relationship between the center of the ankle joint and the tripod of the foot. The measurement of the foot and ankle offset (FAO) represents an optimized biomechanical assessment of foot alignment. The objective of this study was to evaluate the correlation between FAO and traditional adult acquired flatfoot deformity (AAFD) markers, measured in different planes. We hypothesized that the FAO would significantly correlate with other radiographic markers of pronounced AAFD. METHODS: In this retrospective comparative study, we included 113 patients with stage II AAFD, 43 men and 70 women, mean age of 53.5 (range, 20-86) years. 3D coordinates (x, y, and z planes) of the foot tripod (most plantar voxel of the first and fifth metatarsal heads, and calcaneal tuberosity) and the center of the ankle joint (most proximal and central voxel of the talar dome) were assessed by 2 blinded and independent fellowship-trained orthopedic foot and ankle surgeons. The FAO was automatically calculated using the 3D coordinates by dedicated software. Multiple WBCT parameters related to the severity of the deformity in the coronal, sagittal, and transverse planes were manually measured. RESULTS: We found overall good to excellent intra- (range, 0.75-0.99) and interobserver (range, 0.73-0.99) reliability for manual AAFD measurements. FAO semiautomatic measurements demonstrated excellent intra- (0.99) and interobserver (0.99) reliabilities. Hindfoot moment arm (HMA) (P < .00001), subtalar horizontal angle (P < .00001), talonavicular coverage angle (P = .00004), and forefoot arch angle (P = .0001) were the only variables found to significantly influence and correlate with FAO measurements, with an R2 value of 0.79. An HMA value of 19.8 mm was found to be a strong threshold predictor of increased values of FAO, with mean values of FAO of 6.5 when the HMA was lower than 19.8 mm and 14.6 when the HMA was equal to or higher than 19.8 mm. CONCLUSION: We found that 3D WBCT semiautomatic measurements of FAO significantly correlated with some traditional markers of pronounced AAFD. Measurements of FAO were also found to be slightly more reliable than the manual measurements. The FAO offers a simple and more complete biomechanical and multiplanar assessment of the AAFD, representing in a single measurement the 3D components of the deformity. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Superficial Siderosis Misdiagnosed As Parkinson's Disease in a 70-year-old Male Breast Cancer Survivor.

A 70-year-old African American male with a history of hypertension, congestive heart failure, breast cancer status-post six rounds of doxorubicin/cyclophosphamide, and Parkinson's disease managed with carbidopa/levodopa presented to the emergency department with bilateral hearing loss and ataxia. The patient was admitted and evaluated for possible traumatic, oncological, and pharmacological etiologies. Further investigation revealed hypointensities along the cerebellar folia and basal cisterns on MRI in addition to the two-year history of progressive bilateral hearing loss and gait ataxia. In view of these findings, the patient was diagnosed with superficial siderosis and Parkinson's medications were discontinued. Superficial siderosis should be considered as a diagnosis in cases of bilateral hearing loss and ataxia in patients with history of anticoagulation and risk factors for prior cerebrovascular accidents or head trauma.

Treatment of Zone 1 Fractures of the Proximal Fifth Metatarsal With CAM-Walker Boot vs Hard-Soled Shoes.

BACKGROUND: Zone 1 fractures of the proximal fifth metatarsal are usually treated nonsurgically using some type of immobilization. The aim of this study was to compare clinical and functional outcomes, time to return to prior activity levels, and rate of bone healing when using a hard-soled shoe (HSS) vs a controlled ankle motion (CAM)-walker boot (CWB). METHODS: Seventy-two consecutive patients with zone 1 fractures of the fifth metatarsal base were treated conservatively with either an HSS or CWB by 2 different providers. We included 57 women and 15 men, average age of 41.3 (range, 16-88) years. Radiographic findings, visual analog scale (VAS) for pain, and American Orthopaedic Ankle & Foot Society (AOFAS) midfoot score were assessed. Patients were followed at 4, 8, 10, 12, and 24 weeks or until asymptomatic and able to return to prior level of activities. Statistical analysis was performed using Mann-Whitney U, Fisher exact, and chi-square tests. P values <.05 were considered significant. RESULTS: Age and gender distributions were similar in both groups (P = .23 and P = .57). Patients had similar VAS and AOFAS scores after 8 (P = .34 and P = .83) and 12 (P = .87 and P = .79) weeks. Average time for bone healing was significantly faster using the CWB (7.2 weeks) when compared to the HSS (8.6 weeks) (P < .001). The average time to return to prior level of activities was similar in both groups (8.3 weeks for CWB and 9.7 weeks for HSS) (P = .11). Fracture displacement was equal in both groups, with a mean of 1.9 mm of displacement in patients using the HSS, and a mean of 1.6 mm in those using the CWB (P = .26). CONCLUSION: Zone 1 fractures of the proximal fifth metatarsal can be treated conservatively with either a hard-soled shoe or a CAM-walker boot. Even though patients treated in the CAM-walker boot demonstrated earlier signs of complete healing, similar clinical and functional results were achieved with both treatments. LEVEL OF EVIDENCE: Level III, retrospective comparative series.