Case 321: Leigh Syndrome.

HISTORY: A 9-month-old preterm male infant born at 33 weeks gestation presented with a 2-month history of developmental decline. The parents reported that over the past several months, they noted regression of milestones, where the infant stopped smiling, crying, expressing himself, or making eye contact. The parents also reported that the infant had multiple seizures during which he would wake up stiff and stare into space for 10-20 seconds while his lips would become blue. The parents were referred to a neurologist, where physical examination was notable for hypotonia. Electroencephalography (EEG) revealed frequent bilateral parietal epileptiform discharges. The patient was subsequently started on lacosamide. The patient's medical history was notable for abnormally low citrulline levels at birth, with negative results of urea cycle disorder testing at the time, along with left inguinal hernia repair performed 3 months ago. More recent laboratory analysis had shown persistently elevated serum lactate and alanine levels. There was no history of travel, recent infection, or vaccine administration. MRI of the brain with spectroscopy was performed for further evaluation.

Safety outcomes and improvement in pain scores after radiologist-performed fluoroscopy-guided interlaminar cervical epidural steroid injection.

INTRODUCTION: Image-guided spine injections are an important tool in the management of patients with a variety of spinal pathologies. Our practice offers radiologist-performed fluoroscopy-guided interlaminar cervical epidural steroid injection (ESI) routinely performed in the outpatient setting. The purpose of this study was to evaluate clinical outcomes and improvement in pain scores after radiologist-performed cervical ESI. METHODS: An institutional database was used to retrospectively identify cervical injections performed between October 2016 and October 2022. All injections were performed at the C7-T1 level utilizing 1.0 mL of 10 mg/mL dexamethasone without epidural anesthetic. The Numerical Rating Scale (NRS) was used to assess pain improvement. Cervical MRI was reviewed to assess pre-injection cervical disease severity. Patient charts were reviewed for any post-injection complications. RESULTS: A total of 251 cervical injections in 186 patients met our inclusion criteria with mean clinical follow up of 28.5 months (range 0.2 - 73.0 months). No patients experienced any major complications after injection. Post-injection pain scores were available for 218 of 251 injections (86.9%) with mean follow-up of 11.8 days (range 6 - 57 days). There was a significant improvement in pain scores from a mean pre-injection NRS score of 5.2/10 to 3.0/10 (p < .0001). 117 patients (53.7%) reported ≥ 50% improvement after injection. Patients who had prior injection were more likely to report ≥ 50% pain improvement after subsequent injection (p = .012). CONCLUSION: Radiologist-performed fluoroscopy-guided interlaminar cervical ESI at the C7-T1 level is a safe and effective tool in the management of patients with cervical pathology.

Case 321.

HISTORY: A 9-month-old preterm male infant born at 33 weeks gestation presented with a 2-month history of developmental decline. The parents reported that over the past several months, they noted regression of milestones, where the infant stopped smiling, crying, expressing himself, or making eye contact. The parents also reported that the infant had multiple seizures during which he would wake up stiff and stare into space for 10-20 seconds while his lips would become blue. The parents were referred to a neurologist, where physical examination was notable for hypotonia. Electroencephalography (EEG) revealed frequent bilateral parietal epileptiform discharges. The patient was subsequently started on lacosamide. The patient's medical history was notable for abnormally low citrulline levels at birth, with negative results of urea cycle disorder testing at the time, along with left inguinal hernia repair performed 3 months ago. More recent laboratory analysis had shown persistently elevated serum lactate and alanine levels. There was no history of travel, recent infection, or vaccine administration. MRI of the brain with spectroscopy was performed for further evaluation (Figs 1-6).

Hypoalbuminemia Increases Mortality after Two-Stage Revision Total Joint Arthroplasty.

Objectives: This study aimed to evaluate the effect of hypoalbuminemia on failure rates and mortality after a two-stage revision for PJI. Methods: 199 Patients (130 knees and 69 hips) with a mean age of 64.7 ± 10.7 years who underwent a two-stage exchange were retrospectively reviewed at a mean of 51.2 ± 39.7 months. Failure of treatment was defined as any revision within the follow-up period, failure to undergo reimplantation, or death within one year of initiating treatment. Results: There were 71 failures (35.7%), including 38 septic failures (19.1%). We found no differences between successful revisions and failures regarding hypoalbuminemia (43% vs. 42% prior to stage 1, P=1 and 32% vs. 29% prior to stage 2, P=0.856). There were also no differences in hypoalbuminemia rates between septic failures and the rest of the cohort (42% vs. 43% prior to stage 1, P=1.0 and 34% vs. 30% prior to stage 2, P=0.674). Hypoalbuminemia prior to stage 2 was a significant predictor of mortality based on multivariate analysis (odds ratio 5.40, CI 1.19-24.54, P=0.029). Hypoalbuminemia was independently associated with a greater length of stay by 2.2 days after stage 1 (P=0.002) and by 1.0 days after the second stage reimplantation (P=0.004). Conclusion: Preoperative hypoalbuminemia is a significant predictor of mortality and increased length of stay following two-stage revision but is not a predictor of failure of PJI treatment. Further study is required to understand if hypoalbuminemia is a modifiable risk factor or a marker for poor outcomes.

Offset Acetabular Liners: Safer Than Previously Thought.

High offset liners help to restore soft tissue tension after primary total hip arthroplasty (THA). However, prior research has reported increased rates of aseptic loosening when using offset components. The purpose of this study was to examine the postoperative complication and revision rates of neutral vs offset acetabular liners at our institution. Two hundred eight primary THAs in 206 patients performed between 2016 and 2018 using neutral or offset liners were reviewed. All patients had a minimum 2-year clinical follow-up (mean, 3.3 years; range, 2.0-5.7 years). Postoperative complications and revision surgeries were reviewed. All offset liners were 4 mm in thickness. Twelve (10.0%) complications occurred in the neutral liner group, and 13 (14.8%) complications occurred in the offset liner group. Two cases of aseptic loosening occurred in the neutral liner group, with no cases reported in the offset liner group. Nine cases (7.5%) in the neutral group required revision surgery, whereas 3 cases in the offset group required revision surgery. Chi-square analysis found no difference between the groups in the rate of postoperative complications, χ2 (1, N=208)=1.09 (P>.05), or the rate of revision, χ2 (1, N=208)=1.56 (P>.05). We found no significant differences between the neutral and offset groups regarding the rates of postoperative complications, aseptic loosening, or revision surgery. Our findings suggest that contemporary high offset liners, up to 4 mm, are safe and effective when attempting to restore native hip mechanics after THA. [Orthopedics. 2023;46(5):e298-e302.].

Low Risk of Acute Iatrogenic Periprosthetic Joint Infection After Prosthetic Joint Aspiration.

BACKGROUND: Synovial fluid analysis is an essential tool in diagnosing periprosthetic joint infection (PJI) after total knee arthroplasty (TKA). However, concern exists that aspiration may introduce infection into a noninfected joint. Therefore, the purpose of this study was to evaluate the incidence of iatrogenic PJI following diagnostic knee aspiration done within 6 months of the primary TKA. METHODS: Between 2017 and 2021, the senior surgeon performed over 4,000 primary TKAs and aspirated 155 knees in 137 patients for whom there was a suspicion for PJI within 6 months of their primary TKA. There were 22 knees diagnosed as infected from the initial aspiration and therefore were excluded from the study. The remaining 133 aspirates in 115 patients who were negative for infection were followed for 6 months for signs and symptoms of PJI to elucidate whether aspiration introduced infection into an initially noninfected joint. RESULTS: There were 70 of 133 knees (52.6%) aspirated between 0 and 6 weeks after index TKA, 40 of 133 (30.1%) between 6 weeks and 3 months, and 23 of 133 (17.3%) between 3 and 6 months. At final follow-up, none of the 133 initially noninfected knees exhibited evidence of subsequent iatrogenic PJI or had subsequent surgery for infection. CONCLUSION: While joint aspiration is a procedure with inherent risks, this study shows that the rate of iatrogenic PJI is extremely low (0%). Therefore, if infection is suspected, the surgeon should consider joint aspiration, even in the initial postoperative period, as the risk for introducing infection is far outweighed by the risk of missing an infection.

Vitamin D3 Supplementation Prior to Total Knee Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: The purpose of this randomized controlled trial was to determine if a one-time dose of vitamin D3 prior to total knee arthroplasty improves function and patient-reported outcomes, while decreasing complications. METHODS: One hundred seven patients undergoing primary total knee arthroplasty were randomized to receive 50,000 international units vitamin D3 (57 patients) or placebo (50 patients) on the morning of surgery. Power analysis determined 45 patients were required in each cohort to detect a minimal clinically important difference of 6 points in the functional component of the 2011 version of the Knee Society Score (KSS), assuming an alpha of 0.05 and power of 80%. KSS and a Timed Up and Go Test (TUGT) were measured preoperatively and at 3 and 6 weeks postoperatively. RESULTS: There was no difference in improvement of KSS at 3 weeks (+4.8 points vitamin D3 versus +3.0 points placebo; P = .6) or 6 weeks (+14.5 points vitamin D3 versus +12.4 points placebo; P = .5) from baseline. There was no difference in change in TUGT at 3 weeks (+1.2 seconds vitamin D3 versus +0.6 seconds placebo; P = .6) or 6 weeks (-0.3 seconds vitamin D3 versus -0.9 seconds placebo; P = .6) from baseline. There were 4 complications in the placebo cohort within the first 90 days postoperatively and 5 complications in the vitamin D3 cohort (P = 1.0). CONCLUSION: Supplementation with 50,000 international units vitamin D3 on the day of surgery failed to demonstrate statistical significant differences in functional KSS, TUGT times, or complications in the early postoperative period compared to placebo. LEVEL OF EVIDENCE: Level I, therapeutic study.

Contralateral Total Hip Arthroplasty Staged Within Six Weeks Increases the Risk of Adverse Events Compared to Unilateral Surgery.

BACKGROUND: The ideal timing for bilateral total hip arthroplasty (THA) remains controversial. This study compared 90-day outcomes after simultaneous bilateral THA and contralateral surgery in staged bilateral THA to a matched cohort of unilateral procedures. METHODS: Patients undergoing primary, elective THA during 2015 to 2020 were reviewed in a national database. Of the 273,281 patients identified, 39,905 (14.6%) were bilateral. Patients were divided into cohorts of unilateral THA, simultaneous bilateral THA, and staged bilateral THA at 1 to 14 days, 15 to 42 days, 43 to 90 days, and 91 to 365 days. Bilateral THA cohorts were matched with unilateral THA patients based on demographics and comorbidities. Ninety-day outcomes after the second THA were compared between matched groups. RESULTS: Simultaneous bilateral THA resulted in higher rates of transfusion (odds ratio [OR] 4.43, 95% confidence interval 2.31-2.63, P < .001), readmission (OR 2.60, 2.01-3.39, P < .001), and any complication (OR 1.86, 1.55-2.24, P < .001) compared to unilateral THA. Contralateral THA staged at 1 to 14 days increased the risk of readmission (OR 1.83, 1.49-2.24, P < .001) and any complication (OR 1.45, 1.26-1.66, P < .001) relative to unilateral THA. Contralateral THA staged at 15 to 42 days increased the risk of periprosthetic joint infection (OR 3.15, 1.98-5.19, P < .001), readmission (OR 1.92, 1.55-2.39, P < .001), and any complication (OR 1.70, 1.46-1.97, P < .001). Contralateral THA staged beyond 42 days resulted in similar or decreased rates of adverse events relative to unilateral THA. CONCLUSIONS: Bilateral THA should be staged a minimum of 6 weeks apart in appropriately selected patients to avoid an increased risk of adverse events after the second THA compared to unilateral THA.

Radiographic and clinical analysis of a Porous-coated metaphyseal cone for revision total Knee arthroplasty.

BACKGROUND: The aim of this study was to evaluate the radiographic and clinical outcomes of a recently introduced metaphyseal cone system for revision TKA. METHODS: 73 revision TKAs in 72 patients were retrospectively reviewed. All patients had a minimum of 2-year clinical follow-up (mean 34.1 months; range 24.0 to 50.3 months). 114 Metaphyseal cones (64 tibial and 50 femoral) of a single manufacturer were implanted. The most common indications for revision were aseptic loosening (56.9%), second stage reimplantation for periprosthetic joint infection (PJI; 26.4%), and instability (12.5%). All femoral and tibial stems were press-fit cementless stems. RESULTS: Ten of 72 patients underwent re-revision: six for infection (8.3%), two for instability (2.8%), one (1.4%) for patellar tendon rupture and one (1.4%) for femoral component loosening (a cone was not utilized at index revision). Two patients had loose cones (one with an isolated tibial cone and one with both femoral and tibial cones) associated with loose implants but declined re-revision. Aseptic survivorship of our patient cohort free from any re-revision surgery was 95.9% at 2 years (95% CI 87.4-98.7%) and 96.5% of cones demonstrated radiographic evidence of osseointegration. At 2-years, the Knee Society Score (KSS) improved from a mean of 17.2 points preoperatively to 57.8 points (p <.0001). CONCLUSIONS: Porous-coated metaphyseal cones from this manufacturer demonstrate excellent aseptic survivorship and radiographic evidence of osseointegration similar to prior designs when used with cementless stems.

Comparison of Features and Outcomes of Undifferentiated Pleomorphic Sarcoma of Bone and Soft Tissue.

BACKGROUND: This investigation compared outcomes of patients with undifferentiated pleomorphic sarcoma of soft tissue (UPS-S) to UPS of bone (UPS-B). METHODS: The Surveillance, Epidemiology, and End Results database was reviewed from 1975-2016. Disease-specific survival (DSS) was estimated using Kaplan-Meier, and a multivariable Cox regression model identified factors prognostic of DSS. The UPS-S cohort consisted of 4529 patients and the UPS-B cohort consisted of 200 patients. The smaller UPS-B cohort was bootstrapped to create a size-matched cohort of 4500 patients. RESULTS: The median age of patients with UPS-S was 67 (54;78) y compared to 55 (40;69) y for UPS-B patients (P < 0.001). For UPS-S, the median DSS was 317 mo compared to 70 for UPS-B (P = 0.020). On multivariable analysis for UPS-S, age (HR, 1.018; 95% CI, 1.01-1.03; P < 0.001), non-extremity tumors (HR, 1.490; 95% CI 1.14-1.95; P = 0.004), and AJCC Stage III (HR, 2.238; 95% CI 1.2-4.17; P = 0.011), and Stage IV (HR, 9.388; 95% CI 4.69-18.79; P < 0.001) disease were negative prognostic factors, while surgery (HR 0.234; 95% CI, 0.16-0.34; P < 0.001) was a positive prognostic factor. For UPS-B, tumor size > 8 cm (HR, 3.101; 95% CI, 1.09-8.75; P = 0.033) was the only prognostic factor identified. CONCLUSIONS: The current study found a strong association between surgery and survival for UPS-B patients on a univariable analysis, but no treatment type was associated with survival in a multivariable model. Further research is needed to reliably inform the optimal treatment of these patients.

Malseating of modular dual mobility liners.

AIMS: Prior studies have identified that malseating of a modular dual mobility liner can occur, with previous reported incidences between 5.8% and 16.4%. The aim of this study was to determine the incidence of malseating in dual mobility implants at our institution, assess for risk factors for liner malseating, and investigate whether liner malseating has any impact on clinical outcomes after surgery. METHODS: We retrospectively reviewed the radiographs of 239 primary and revision total hip arthroplasties with a modular dual mobility liner. Two independent reviewers assessed radiographs for each patient twice for evidence of malseating, with a third observer acting as a tiebreaker. Univariate analysis was conducted to determine risk factors for malseating with Youden's index used to identify cut-off points. Cohen's kappa test was used to measure interobserver and intraobserver reliability. RESULTS: In all, 12 liners (5.0%), including eight Stryker (6.8%) and four Zimmer Biomet (3.3%), had radiological evidence of malseating. Interobserver reliability was found to be 0.453 (95% confidence interval (CI) 0.26 to 0.64), suggesting weak inter-rater agreement, with strong agreement being greater than 0.8. We found component size of 50 mm or less to be associated with liner malseating on univariate analysis (p = 0.031). Patients with malseated liners appeared to have no associated clinical consequences, and none required revision surgery at a mean of 14 months (1.4 to 99.2) postoperatively. CONCLUSION: The incidence of liner malseating was 5.0%, which is similar to other reports. Component size of 50 mm or smaller was identified as a risk factor for malseating. Surgeons should be aware that malseating can occur and implant design changes or changes in instrumentation should be considered to lower the risk of malseating. Although further follow-up is needed, it remains to be seen if malseating is associated with any clinical consequences. Cite this article: Bone Jt Open 2021;2(10):858-864.

Quantitative sodium MRI of the human brain at 9.4 T provides assessment of tissue sodium concentration and cell volume fraction during normal aging.

Sodium ion homeostasis is a fundamental property of viable tissue, allowing the tissue sodium concentration to be modeled as the tissue cell volume fraction. The modern neuropathology literature using ex vivo tissue from selected brain regions indicates that human brain cell density remains constant during normal aging and attributes the volume loss that occurs with advancing age to changes in neuronal size and dendritic arborization. Quantitative sodium MRI performed with the enhanced sensitivity of ultrahigh-field 9.4 T has been used to investigate tissue cell volume fraction during normal aging. This cross-sectional study (n = 49; 21-80 years) finds that the in vivo tissue cell volume fraction remains constant in all regions of the brain with advancing age in individuals who remain cognitively normal, extending the ex vivo literature reporting constant neuronal cell density across the normal adult age range. Cell volume fraction, as measured by quantitative sodium MRI, is decreased in diseases of cell loss, such as stroke, on a time scale of minutes to hours, and in response to treatment of brain tumors on a time scale of days to weeks. Neurodegenerative diseases often have prodromal periods of decades in which regional neuronal cell loss occurs prior to clinical presentation. If tissue cell volume fraction can detect such early pathology, this quantitative parameter may permit the objective measurement of preclinical disease progression. This current study in cognitively normal aging individuals provides the basis for the pursuance of investigations directed towards such neurodegenerative diseases.