Post-traumatic Total Hip Arthroplasty After Acetabular Fractures: Benefits of the Hardinge Approach.

Post-traumatic arthritis is a common sequelae after undergoing open reduction and internal fixation (ORIF) of acetabular fractures. This often necessitates conversion to total hip arthroplasty (THA) to help alleviate pain and improve function for these patients. Unfortunately, dislocation rates for post-traumatic THA have been alarmingly high especially when the posterior approach has been used. In the setting of prior soft tissue disruption, the theoretical risk of dislocation is even greater. Conversely, the lateral or the abductor-split approach (Hardinge) is associated with decreased dislocation rates. In this retrospective case series, we evaluated the dislocation rate of the Hardinge approach on patients who underwent THA after developing post-traumatic arthritis after acetabulum ORIF. All patients who matched CPT code 27132 (Repair, Revision, and/or Reconstruction Procedures on the Pelvis and Hip Joint), from January 2009 to December 2019, and treated by the senior author, were pulled from the electronic medical record at the University of Pittsburgh Medical Center. Thirty-one of the resultant 110 were treated with THA for post-traumatic arthrosis through a lateral, abductor-splitting Hardinge approach and met the inclusion criteria for further study. Our case series involves 31 patients who underwent post-traumatic THA through a Hardinge approach: the mean age at the time of index acetabular ORIF is 48.5 years, the mean age at the time of THA is 53.5 years, and the mean interval between ORIF and ultimate THA was five years. The mean length of follow-up after THA was 22.4 months. Overall, patients did well with an all-cause revision rate of 9.7%, with no revision performed for loosening of either the acetabular or femoral component. One patient developed an infection. No patient in our group sustained a dislocation, and all implants were stable without evidence of radiographic loosening at the final follow-up. This study found satisfactory results with patients undergoing THA via lateral or abductor split approach (Hardinge) for post-traumatic arthritis after acetabular ORIF. The use of a Hardinge approach for post-traumatic reconstruction of the hip may be protective against dislocation without increasing baseline risks in this difficult patient population.

High variability of tibial slope measurement methods in daily clinical practice: Comparisons between measurements on lateral radiograph, magnetic resonance imaging, and computed tomography.

BACKGROUND: Tibial slope measurements are important in guiding clinical decisions in the field of orthopedic surgery. However, there are multiple techniques across different medical imaging modalities and little is known about its impact on result and validity of the measurement. Therefore, the purpose of this study was to compare tibial slope measurements from lateral radiographs, magnetic resonance imaging (MRI) and computed tomography (CT) scans in order to better assess the clinical significance of measured tibial slope values. METHODS: Twenty patients with complete medical imaging (lateral radiographs, MRI, CT scans) undergoing anterior cruciate ligament revision surgery were included. The tibial slope of the medial and lateral plateau were measured and compared using the methods of Dejour et al. and Utzschneider et al. on lateral radiographs, by Hudek et al. and Hashemi et al. on MRI and CT scans, and by Zhang et al. on three-dimensional reconstructions of CT scans. RESULTS: Mean differences up to 5.4 ± 2.8° (P < 0.05) and 4.9 ± 2.6° (P < 0.05) between different measurement methods were found for the medial and lateral tibial slope, respectively. Depending on how the tibial shaft axis was defined, significant differences between the respective measurement methods and a relevant degree of variability were identified. Pearson correlation coefficients between the measurement methods varied distinctly from moderate to strong correlations. CONCLUSIONS: Tibial slope measurements have a high degree of variability and inaccuracy between imaging modalities and different measurement methods. Care must be taken when deciding on indications based on individual modality measurements.

The femoral posterior fan-like extension of the ACL insertion increases the failure load.

PURPOSE: To examine the role of the posterior fan-like extension of the ACL's femoral footprint on the ACL failure load. METHODS: Sixteen (n = 16) fresh frozen, mature porcine knees were used in this study and randomized into two groups (n = 8): intact femoral ACL insertion (ACL intact group) and cut posterior fan-like extension of the ACL (ACL cut group). In the ACL cut group, flexing the knees to 90°, created a folded border between the posterior fan-like extension and the midsubstance insertion of the femoral ACL footprint and the posterior fan-like extension was dissected and both areas were measured. Specimens were placed in a testing machine at 30° of flexion and subjected to anterior tibial loading (60 mm/min) until ACL failure. RESULTS: The intact ACL group had a femoral insertion area of 182.1 ± 17.1 mm2. In the ACL cut group, the midsubstance insertion area was 113.3 ± 16.6 mm2, and the cut posterior fan-like extension portion area was 67.1 ± 8.3 mm2. The failure load of the ACL intact group was 3599 ± 457 N and was significantly higher (p < 0.001) than the failure load of the ACL cut group 392 ± 83 N. CONCLUSION: Transection of the posterior fan-like extension of the ACL femoral footprint has a significant effect on the failure load of the ligament during anterior loading at full extension. Regarding clinical relevance, this study suggests the importance of the posterior fan-like extension of the ACL footprint which potentially may be retained with remnant preservation during ACL reconstruction. Femoral insertion remnant preservation may allow incorporation of the fan-like structure into the graft increasing graft strength.

The iliotibial band and anterolateral capsule have a combined attachment to the Segond fracture.

The purpose of this report was to describe the injury mechanism, surgical findings, and outcomes in a 21-year-old professional female football player who presented with a complete anterior cruciate ligament (ACL) rupture and Segond fracture. Interview and video analysis were performed to elicit the injury mechanism. Clinical examination and imaging revealed a complete ACL tear, Segond fracture, lateral meniscus tear, MCL sprain, and posterolateral corner sprain. Examination under anaesthesia revealed Grade 2 pivot shift and varus/valgus instability. Surgical examination revealed attachment of the posterior fibres of the iliotibial band and the lateral capsule to the Segond fragment. The fracture was reduced with suture fixation, and an anatomic ACL reconstruction was performed. Follow-up demonstrated rotatory and anterior tibial translation stability, and imaging at 7 months post-operatively revealed no movement and continued osseous integration of the Segond fragment. Level of evidence V.

Increased lateral tibial posterior slope is related to tibial tunnel widening after primary ACL reconstruction.

PURPOSE: The purpose of the study was to determine the influence of femoral and tibial bone morphology on the amount of femoral and tibial tunnel widening after primary anatomic ACL reconstruction. It was hypothesized that tibial and femoral bone morphology would be significantly correlated with tunnel widening after anatomic ACL reconstruction. METHODS: Forty-nine consecutive patients (mean age 21.8 ± 8.1 years) who underwent primary single-bundle anatomic ACL reconstruction with hamstring autograft were enrolled. Two blinded observers measured the bone morphology of tibia and femur including, medial and lateral tibial posterior slope, medial and lateral tibial plateau width, medial and lateral femoral condyle width, femoral notch width, and bicondylar width on preoperative magnetic resonance imaging (MRI) scans. Tibial and femoral tunnel width at three points (aperture, mid-section, and exit) were measured on standard anteroposterior radiograph from 1 week and 1 year postoperatively (mean 12.5 ± 2 months). Tunnel width measurements at each point were compared between 1 week and 1 year to calculate percent of tunnel widening over time. Multivariable linear regression was used to analyze correlations between bone morphology and tunnel widening. RESULT: Increase in lateral tibial posterior slope was the only independent bony morphology characteristics that was significantly correlated with an increased tibial tunnel exit widening (R = 0.58). For every degree increase in lateral tibial posterior slope, a 3.2% increase in tibial tunnel exit width was predicted (p = 0.003). Excellent inter-observer and intra-observer reliability were determined for the measurements (ICC = 0.91 and 0.88, respectively). CONCLUSION: Increased lateral tibial posterior slope is an important preoperative anatomic factor that may predict tunnel widening at the tibial tunnel exit. In regard to clinical relevance, the results of this study suggest that lateral tibial posterior slope be measured preoperatively. In patients with increased lateral tibial posterior slope, more rigid graft fixation and a more conservative physical therapy regiment may be preferred. Level of evidence IV.

The anterolateral complex of the knee: a pictorial essay.

Injuries to the anterolateral complex of the knee can result in increased rotatory knee instability. However, to diagnose and treat patients with persistent instability properly, surgeons need to understand the multifactorial genesis as well as the complex anatomy of the anterolateral aspect of the knee in its entirety. While recent research focused primarily on one structure (anterolateral ligament-ALL), the purpose of this pictorial essay is to provide a detailed layer-by-layer description of the anterolateral complex of the knee, consisting of the iliotibial band with its superficial, middle, deep, and capsulo-osseous layer as well as the anterolateral joint capsule. This may help surgeons to not only understand the anatomy of this particular part of the knee, but may also provide guidance when performing extra-articular procedures in patients with rotatory knee instability. Level of evidence V.

Predicting Spontaneous Stone Passage in Prepubertal Children: A Single Institution Cohort.

INTRODUCTION: No method currently exists for predicting which young child with a renal or ureteral stone will require surgery as opposed to pass the stone. Our goals were to analyze practice patterns at a major pediatric center and to identify factors that predicted spontaneous stone passage. METHOD: A retrospective review of all prepubertal patients (≤ 11 years) presenting to our institution from January 2005 to July 2014 with symptomatic nephrolithiasis was performed. Demographic data and stone details were reviewed, including anatomic location, size, and outcomes. Spontaneous stone passage was determined by parental report and/or stone absence on imaging obtained within 6 months after initial diagnosis. RESULTS: A total of 119 eligible patients were identified, with an average age of 88.7 months (4-143). Forty eight (40.3%) patients spontaneously passed their stone and the remaining 59.7% required endoscopic intervention. Overall, 79.0% had symptomatic presentation (flank pain, hematuria) and 39.5% of patients were obstructing stones. Symptomatic presentation was more common with ureteral (86.5%) than with renal (66.7%) stones, but was not associated with increased passage of stones in general (p-value 0.1765). Of the 48 patients who spontaneously passed stones, 11 (24.4%) were renal stones compared with 37 (50.0%) ureteral stones. The average size of spontaneously passed stones was 3.5 mm (2-8) for renal and 3.4 mm (1-7) for ureteral stones. Based on logistic regression, the single most important predictor of stone passage was stone size (p-value <0.001). The odds of passage were 3.1 times higher for ureteral stones compared with renal stones (p = 0.0070) when not controlling for size. CONCLUSION: In prepubertal patients, ureteral stones with an average size of 3.5 mm or less are more likely to pass spontaneously. Based on this information, watchful waiting is a reasonable option in clinically stable nonseptic patients with renal/ureteral stones of this size.

Adipose-derived mesenchymal stromal cells from genetically modified pigs: immunogenicity and immune modulatory properties.

BACKGROUND AIMS: The immunomodulatory and anti-inflammatory effects of mesenchymal stromal cells (MSC) could prove to be a potential therapeutic approach for prolongation of survival of cell xenotransplantation. Adipose (Ad) MSC from genetically modified pigs could be an abundant source of pig donor-specific MSC. METHODS: Pig (p) MSC were isolated from adipose tissue of α1,3-galactosyltransferase gene knock-out pigs transgenic for human (h) CD46 (GTKO/hCD46), a potential source of islets. After characterization with differentiation and flow cytometry (FCM), AdMSC were compared with bone marrow (BM) MSC of the same pig and human adipose-derived (hAd) MSC. The modulation of human peripheral blood mononuclear cell (hPBMC) responses to GTKO pig aortic endothelial cells (pAEC) by different MSC was compared by measuring 3H-thymidine uptake. The supernatants from the AdMSC cultures were used to determine the role of soluble factors. RESULTS: GTKO/hCD46 pAdMSC (i) did not express galactose-α1,3-galactose (Gal) but expressed hCD46, (ii) differentiated into chondroblasts, osteocytes and adipocytes, (iii) expressed stem cell markers, (iv) expressed lower levels of Swine Leucocyte Antigen I (SLAI), Swine Leucocyte Antigen II DR (SLAIIDR) and CD80 than pAEC before and after pig interferon (IFN)-γ stimulation. The proliferative responses of hPBMC to GTKO/hCD46 pAdMSC and hAdMSC stimulators were similar, and both were significantly lower than to GTKO pAEC (P < 0.05). The proliferation of hPBMC to GTKO pAEC was equally suppressed by GTKO/hCD46 pAdMSC and hAdMSC (P > 0.05). The supernatant from GTKO/hCD46 pAdMSC did not suppress the human xenoresponse to GTKO pAEC, which was cell-cell contact-dependent. CONCLUSIONS: Initial evidence suggests that genetically modified pAdMSC function across the xenogeneic barrier and may have a role in cellular xenotransplantation.