The Anatomical Course of the Femoral Nerve with Regard to the Direct Anterior Approach for Total Hip Arthroplasty.

BACKGROUND: Femoral nerve (FN) injury is noted as a serious neurological complication following total hip arthroplasty performed via a direct anterior approach (DAA). Therefore, we aimed to clarify the anatomical course of the FN around the acetabular rim and in relation to retractor placement during DAA. METHODS: According to standard protocol, a DAA for total hip arthroplasty was performed on 69 hemipelves from formalin-preserved full-body donors. The surgery was halted after retractor placement at the anterior part of the acetabulum. Then dissection was performed to expose the FN and the iliopsoas muscle. Various measurements were taken using a reference line from the anterior superior iliac spine to the acetabulum's center. A total of 6 measurement points, one every 30° from 0° to 150° along the reference line were used to determine the association between the FN and the retractor tip (RT) and the anterior acetabular rim. RESULTS: The mean distance from the RT to the FN was 22.5 millimeters (mm). The distance from the FN to the anterior acetabular rim decreased from 0 to 90°, where it was 18.8 mm, before increasing again to 27.3 mm at 150°. CONCLUSIONS: In our cadaveric study, the FN was within 11 to 36 mm of the RT. Second, we found the FN to be closest to the anterior acetabular rim at 90° and 120°. Accordingly, special care should be taken during retractor placement, and if possible, placement at 90° and 120° avoided.

The Anatomical Course of the Superior Gluteal Vessel Bundle with Regard to Different Approaches in Total Hip Arthroplasty.

BACKGROUND: Iatrogenic vascular injury during total hip arthroplasty (THA) is rare, reported at rates of 0.05 to 0.3%, but a potentially limb-threatening and life-threatening complication. We aimed to describe safe and danger zones for the superior gluteal vessel bundle (SGV bundle) with reference to different THA approaches. METHODS: There were 27 formalin-fixed cadavers with 49 hemipelves dissected. The course and distribution of the SGV bundle were investigated with the help of anatomical landmarks like the greater trochanter, the iliac tubercle (IT), and the ischial tuberosity. RESULTS: We found and exposed the SGV bundle in all 49 specimens with no sex-specific differences. No SGV bundle was encountered up to 28 mm from the greater trochanter and up to 16 mm below the IT. The zone with the highest probability of finding the vessels was 25 to 65 mm below the IT in 39 (80%) cases - defining a danger zone (in relation to the skin incision) in the proximal fourth for the direct anterior approach, in the proximal half for the antero-lateral approach, in the proximal fifth for the direct lateral approach, and almost no danger zone for the posterior approach. CONCLUSIONS: Special care in proximal instrument placement should be taken during THA. When extending one of the surgical approaches, manipulations in the proximal, cranial surgical window should be performed with the utmost care to avoid SGV bundle injury.

Evaluation of Classic and Quantitative Imaging Features in the Differentiation of Benign and Atypical Lipomatous Soft Tissue Tumors Using a Standardized Multiparametric MRI Protocol: A Prospective Single-Centre Study in 45 Patients.

BACKGROUND: Discrimination between benign and atypical lipomatous tumors (ALT) is important due to potential local complications and recurrence of ALT but can be difficult due to the often-similar imaging appearance. Using a standardized MRI protocol, this study aimed to rank established and quantitative MRI features by diagnostic value in the differentiation of benign and atypical lipomatous tumors and to develop a robust scoring system. METHODS: Patients with clinical or sonographic suspicion of a lipomatous tumor were prospectively and consecutively enrolled from 2015 to 2019 after ethic review board approval. Histology was confirmed for all ALT and 85% of the benign cases. Twenty-one demographic and morphologic and twenty-three quantitative features were extracted from a standardized MRI protocol (T1/T2-proton-density-weighting, turbo-inversion recovery magnitude, T2* multi-echo gradient-echo imaging, qDIXON-Vibe fat-quantification, T1 relaxometry, T1 mapping, diffusion-weighted and post-contrast sequences). A ranking of these features was generated through a Bayes network analysis with gain-ratio feature evaluation. RESULTS: Forty-five patients were included in the analysis (mean age, 61.2 ± 14.2 years, 27 women [60.0%]). The highest-ranked ALT predictors were septation thickness (gain ratio merit [GRM] 0.623 ± 0.025, p = 0.0055), intra- and peritumoral STIR signal discrepancy (GRM 0.458 ± 0.046, p < 0.0001), orthogonal diameter (GRM 0.554 ± 0.188, p = 0.0013), contrast enhancement (GRM 0.235 ± 0.015, p = 0.0010) and maximum diameter (GRM 0.221 ± 0.075, p = 0.0009). The quantitative features did not provide a significant discriminatory value. The highest-ranked predictors were used to generate a five-tiered score for the identification of ALTs (correct classification rate 95.7% at a cut-off of three positive items, sensitivity 100.0%, specificity 94.9%, likelihood ratio 19.5). CONCLUSIONS: Several single MRI features have a substantial diagnostic value in the identification of ALT, yet a multiparametric approach by a simple combination algorithm may support radiologists in the identification of lipomatous tumors in need for further histological assessment.

Treatment of periprosthetic femoral fractures following total hip arthroplasty: results of an online survey of the European Hip Society.

BACKGROUND: Periprosthetic femoral fractures (PPF) are a devastating complication after total hip arthroplasty (THA). Both trauma and adult reconstruction surgeons or combined teams treat these fractures following management algorithms. The aim of this study is to investigate the current treatment of PPF by members of the European Hip Society (EHS). METHODS: An online survey of the members of the European Hip Society (EHS) was conducted. 20 cases of periprosthetic fracture were presented and surgeons were asked to answer questions regarding classification, treatment and postoperative treatment protocol. RESULTS: A total of 132 (130 male; 2 female) EHS members responded. Mean years in surgical practice was 18.8 (min. 1 year; max. 50 years). The preferred surgical method was combined open reduction and internal fixation (ORIF) (30.3%) for AG fractures, ORIF with cables (30.4%) for AL fractures, combined ORIF (cable and plate) for B1 fractures (49.2%), stem revision with cables for B2 fractures (73.1%), stem revision with cables for B3 (55.9%) fractures and combined ORIF (cable and plate: 55.5%) for C fractures. Surprisingly, 10.8% suggested various stem revision techniques for B1 and 17.4% for C fractures. Strong variations were observed regarding postoperative weight-bearing protocol. CONCLUSIONS: A strong consensus was found for the choice of conservative or surgical treatment of the different PPF types according to the Vancouver Classification. Various stem revision techniques were the preferred surgical techniques for Vancouver B2 (91.2%) and B3 (88.6%) fractures. However, for postoperative weight-bearing, when the ORIF technique was used, a significant variation of protocols was found.

Early Discovery of Children With Lysosomal Acid Lipase Deficiency With the Universal Familial Hypercholesterolemia Screening Program.

Lysosomal acid lipase deficiency (LAL-D) is an autosomal recessive lysosomal storage disorder, caused by homozygous or compound heterozygous pathogenic variants in the LIPA gene. Clinically, LAL-D is under- and misdiagnosed, due to similar clinical and laboratory findings with other cholesterol or liver misfunctions. As a part of the Slovenian universal familial hypercholesterolemia (FH) screening, LAL-D is screened as a secondary condition among other rare dyslipidemias manifesting with hypercholesterolemia. Out of 669 children included, three were positive for a homozygous disease-causing splicing variant NM_000235.4: c.894G > A (NP_000226.2:p. Gln298Gln) in the LIPA gene (NG_008194.1). The mean age by the diagnosis of LAL-D was 9.8 ± 0.9 years. Moreover, all three LAL-D-positive children had an important elevation of transaminases and decreased activity of the lysosomal acid lipase enzyme. Abdominal MRI in all children detected an enlarged liver but a normal-sized spleen. In conclusion, universal FH screening algorithms with the confirmatory genetic analysis in the pediatric population enable also rare dyslipidemia detection at an early age. An important clinical criterion for differentiation between FH and the LAL-D-positive children has elevated transaminase levels (AST and ALT). In all three LAL-D positive children, an improvement in cholesterol and transaminase levels and steatosis of the liver has been seen after early treatment initiation.

Acetabular defect management and revision arthroplasty via the direct anterior approach.

OBJECTIVE: Acetabular revision arthroplasty and osseous defect management through the direct anterior approach (DAA) with or without proximal extension. INDICATIONS: Aseptic or septic component loosening, periacetabular osseous defects, pelvic discontinuity, intrapelvic cup protrusion, anterior pseudotumors, iliopsoas tendonitis, polyethylene wear or iliopsoas abscess. CONTRAINDICATIONS: Clinically relevant gluteal tendon lesions, active infection, morbid obesity, large abdominal pannus, ASA (American Society of Anesthesiologists) score > III, inguinal skin infection. SURGICAL TECHNIQUE: Electrocautery dissection is recommended to dissect the Hueter interval and to debulk pericapsular scar tissue. At all times during capsular debulking, it should be made sure not to damage the iliopsoas tendon or the neurovascular bundle. A stepwise releasing sequence can facilitate dislocation of the prosthesis. Most cases can be revised via the standard DAA but certain circumstances require an intra- or extrapelvic extension. Access to the anterior gluteal surface of the ilium can be provided using a "tensor snip". More posterior access is provided by the extensile extrapelvic approach described by Smith-Petersen. The intrapelvic Levine extension offers access to the entire visceral surface of the ilium and large parts of the anterior column. POSTOPERATIVE MANAGEMENT: Patient revised via the intra- or extrapelvic extension and patients suffering from extensive soft tissue or osseous defects should undergo postoperative weight-bearing restrictions with 20 kg for 6 weeks. RESULTS: Based on our studies, there is no limitation on the type of acetabular implant that can be used in DAA revision arthroplasty. Moreover, virtually all types of periacetabular osseous defects can be managed through the approach and its extensions. Acetabular revision arthroplasty via the DAA and its extensions is safe and can result in good midterm results.

Proximal femoral replacement using the direct anterior approach to the hip.

OBJECTIVE: Proximal femoral replacement (PFR) is a salvage procedure originally developed for reconstruction after resection of sarcomas and metastatic cancer. These techniques can also be adapted for the treatment of non-oncologic reconstruction for cases involving massive proximal bone loss. The direct anterior approach (DAA) is readily utilized for revision total hip arthroplasty (THA), but there have been few reports of its use for proximal femoral replacement. INDICATIONS: Aseptic, septic femoral implant loosening, periprosthetic femoral fracture, oncologic lesions of the proximal femur. The most common indication for non-oncologic proximal femoral placement is a severe femoral defect Paprosky IIIB or IV. CONTRAINDICATIONS: Infection. SURGICAL TECHNIQUE: In contrast to conventional DAA approaches and extensions, we recommend starting the approach 3 cm lateral to the anterior superior iliac spine and performing a straight incision directed towards the fibular head. After identification and incision of the tensor fasciae lata proximally and the lateral mobilization of the iliotibial tract distally, the vastus lateralis muscle can be retracted medially as far as needed. Special care should be taken to avoid injuries to the branches of the femoral nerve innervating the vastus lateralis muscle. If required, the distal extension of the DAA can continue all the way to the knee to allow implantation of a total femoral replacement. The level of the femoral resection is detected with an x­ray. In accordance with preoperative planning, the proximal femur is resected. Ream and broach the distal femoral fragment to the femoral canal. With trial implants in place, leg length, anteversion of the implant and hip stability are evaluated. It is crucial to provide robust reattachment of the abductor muscles to the PFR prosthesis. Mesh reinforcement can be used to reinforce the muscular attachment if necessary. POSTOPERATIVE MANAGEMENT: We typically use no hip precautions other than to limit combined external rotation and extension for 6 weeks. In most cases, full weight bearing is possible after surgery. RESULTS: A PFR was performed in 16 patients (mean age: 55.1 years; range 17-84 years) using an extension of the DAA. The indication was primary bone sarcoma in 7 patients, metastatic lesion in 6 patients and massive periprosthetic femoral bone loss in 3 patients. Complications related to the surgery occurred in 2 patients (both were dislocation). Overall, 1 patient required reoperation and 1 patient died because of his disease. Mean follow-up was 34.5 months.

Femoral revision with the direct anterior approach.

OBJECTIVE: The advantages of the direct anterior approach (DAA) in primary total hip arthroplasty as a minimally invasive, muscle-sparing, internervous approach are reported by many authors. Therefore, the DAA has become increasingly popular for primary total hip arthroplasty (THA) in recent years, and the number of surgeons using the DAA is steadily increasing. Thus, the question arises whether femoral revisions are possible through the same interval. INDICATIONS: Aseptic, septic femoral implant loosening, malalignment, periprosthetic joint infection or periprosthetic femoral fracture. CONTRAINDICATIONS: A draining sinus from another approach. SURGICAL TECHNIQUE: The incision for the primary DAA can be extended distally and proximally. If necessary, two releases can be performed to allow better exposure of the proximal femur. The DAA interval can be extended to the level of the anterior superior iliac spine (ASIS) in order to perform a tensor release. If needed, a release of the external rotators can be performed in addition. If a component cannot be explanted endofemorally, and a Wagner transfemoral osteotomy or an extended trochanteric osteotomy has to be performed, the skin incision needs to be extended distally to maintain access to the femoral diaphysis. POSTOPERATIVE MANAGEMENT: Depending on the indication for the femoral revision, ranging from partial weight bearing in cases of periprosthetic fractures to full weight bearing in cases of aseptic loosening. RESULTS: In all, 50 femoral revisions with a mean age of 65.7 years and a mean follow-up of 2.1 years were investigated. The femoral revision was endofemoral in 41 cases, while a transfemoral approach with a lazy­S extension was performed in 9 patients. The overall complication rate was 12% (6 complications); 3 patients or 6% of the included patients required reoperations. None of the implanted stems showed a varus or valgus position. There were no cases of mechanical loosening, stem fracture or subsidence. Median WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score before surgery improved significantly from preoperative (52.5) to postoperative (27.2).

Aerosol morphology and particle size distribution in orthopaedic bone machining: a laboratory worst-case contamination simulation. Is high-speed bone machining potentially harmful by pollution and quality schemes and what measures could be taken for prevention?

AIM OF THE STUDY: High-speed bone machining devices with irrigation fluid were used in surgery to spread aerosols and toss tissue particles of varying morphology into the operating room. Based on measurements taken on a phantom object, the shape, size, and spatial contamination distribution of such particles were assessed. METHOD: Cadaveric femoral heads were continuously machined with a spherical bur, manually held at a fixed attack angle. The irrigation fluid used during bone machining was enriched with bacteria to act as a tracer to quantify the spatial contamination. A vertical board equipped with snippets served as a phantom object to assess contamination load and morphology of airborne particles. RESULTS: Eight-nine percent of the particles had a non-circular cross section. The detected particle size ranged across six orders of magnitude, from 0.006 to 4 mm2 with a median particle size of 0.125 mm2. The CFU counts observed after the standard machining time ranged from 7 to 240, with a median of 2 CFUs. The highest median contamination was seen at the upper right corner of the phantom. DISCUSSION: The experiments show that contaminating particles of a wide variety of shapes and sizes are part of the aerosol created by high-speed burring. While protection of personnel and equipment is always important, surgical helmets should be worn, especially at contamination hotspots, and gloves should be replaced at the end of machining. Sensitive instruments and measuring devices-such as optical sensors-should also be protected effectively, as the optical measurement may be obstructed by aerosol particles.

An intraoperative assessment of bacterial contamination on surgical helmets and gloves during arthroplasty surgeries.

INTRODUCTION: Infection is a devasting complication after primary and revision arthroplasty. Therefore, identifying potential sources of infection can help to reduce infection rates. The aim of this study was to identify the impact and potential risk of contamination for glows and surgical helmets during arthroplasty procedures. METHODS: Surveillance cultures were used to detect contamination of the glow interface during the surgery and the surgical helmets immediately at the end of the surgery. The cultures were taken from 49 arthroplasty procedures from the surgeon as well as the assisting surgeon. RESULTS: In total, 196 cultures were taken. 31 (15.8%) of them showed a contamination. 12 (13.5%) of 98 cultures taken from the surgical helmets were positive, while 18 (18.3%) of 96 cultures taken from the gloves showed a contamination. DISCUSSION: The study showed that during arthroplasty procedures, surgical helmets and gloves were frequently contaminated with bacteria. In 20 of 49 (40.8%) arthroplasty surgeries, either the surgical helmet or the gloves showed a contamination. Surgeons should be aware that they might be a source for infection during arthroplasty surgeries.

Migration characteristics of the Corail hydroxyapatite-coated femoral stem-a retrospective clinical evaluation and migration measurement with EBRA.

PURPOSE: Uncemented stem migration analysis by EBRA-FCA (Einzel-Bild-Roentgen Analyse, Femoral Component Analysis) has been seen to be a good predictive indicator for early implant failure. In this study, we investigated the migration behavior of a cementless press-fit stem after two years follow-up. Stem type and postoperative gap between collar and femur were evaluated as a risk factor. METHODS: Applying a retrospective study design, we reviewed all consecutive patients who between 2013 and 2017 received a cementless press-fit Corail stem (DePuy Orthopaedics Inc., Warsaw, IN, USA) at our Department. We reviewed medical histories and performed radiological measurements using EBRA-FCA software. RESULTS: A total of 109 stems in 105 patients (female: 60; male: 45) fulfilled our inclusion criteria. Mean age at surgery was 67.8 (range, 21.6-90.5) years. EBRA migration analysis showed a mean subsidence of 1.8 mm (range, 0.0-12.1) at final follow-up. At 18 months mean subsidence of collared stems was significantly lower than in the collarless group [1.3 mm (range, 0.0-7.6) vs. 3.2 mm (range, 0.5-10.7), p = 0.0104]. Collared stems resting on the femoral cut presented a tendency to less subsidence than did collared stems showing a postoperative gap between collar and femur (1.3 vs. 2.0 mm) without finding statistical significance (p > 0.05). CONCLUSIONS: Low subsidence and the migration pattern of the cementless press-fit stem may predict a good long-term result. Collared stems investigated in our study provide good stability and are able to prevent significant subsidence. Trial registration number and date of registration: Number: 20181024-1875; Date: 2018-10-24.

The effect of gastrocnemius resection on knee flexion in a total knee arthroplasty model.

INTRODUCTION: Flexion contracture in knee arthritis and total knee arthroplasty (TKA) is a common and significant problem. An improvement in knee extension in patients with TKA and mild flexion contractures has been observed clinically when a gastrocnemius recession was performed for other concomitant conditions. The goal of this study was to quantify the effect of gastrocnemius recession on knee flexion in TKA cadaver model. MATERIALS AND METHODS: Range of motion (ROM) of 23 cadaveric knees was determined with a navigation system before and after performing TKA using a medial parapetallar approach and after performing a gastrocnemius recession. Varus-valgus, flexion-extension, and internal-external rotation angles of the knee joint were recorded with leg in full extension and in 90°of knee flexion. Extension and flexion gaps were measured using a gap tensioning device. Dorsiflexion of the foot was measured with a goniometer when a torque moment of 10 Nm was applied to the ankle joint. RESULTS: A statistically significant improvement of 5° in knee extension was observed following gastrocnemius recession (P = 0.015). Varus and valgus angles, internal, and external rotation were unaffected by gastrocnemius recession. Ankle dorsiflexion increased by 9° following gastrocnemius recession (P ≤ 0.001). CONCLUSIONS: Performing a gastrocnemius recession improves the knee extension in TKA knees with flexion contractures. Gastrocnemius recession may be a useful technique to improve terminal extension in TKA.

Subsidence of a metaphyseal-anchored press-fit stem after 4-year follow-up: an EBRA-FCA analysis.

PURPOSE: Uncemented stem migration analysis by EBRA-FCA (Einzel-Bild-Roentgen Analyse, Femoral Component Analyse) has been seen to be a good predictive indicator for early implant failure. In this study, we investigated the migration behavior of a cementless metaphyseal-anchored press-fit stem after 4-year follow-up. METHODS: Applying a retrospective study design, we reviewed all consecutive patients who between 2012 and 2017 received a cementless Accolade II press-fit stem at our Department. We reviewed medical histories and performed radiological measurements using EBRA-FCA software. EBRA-FCA measurements and statistical investigations were performed by two independent investigators. RESULTS: A total of 102 stems in 91 patients (female 60; male 31) fulfilled our inclusion criteria. Mean age at surgery was 66.2 (range 24.3-92.6) years. EBRA migration analysis showed a mean subsidence of 1.4 mm (range 0.0-12.0) at final follow-up. The angle between stem and femur axis was 0.5° (range 0.0°-2.8°) after 48 months. No correlations between gender or Dorr types and subsidence were found (p > 0.05). A body mass index > 30 kg/m2 showed a significant increase in stem subsidence within the first 6 (p = 0.0258) and 12 months (p = 0.0466) postoperative. CONCLUSIONS: Migration pattern of the metaphyseal-anchored stem and a low subsidence rate at final follow-up may predict a good long-term clinical result. TRIAL REGISTRATION: Number: 20181024-1875.

The Impact of the COVID-19 Pandemic on Spine Surgery in Central Europe: A Questionnaire-Based Study.

OBJECTIVE: The severe acute respiratory coronavirus 2 (SARS-CoV2) crisis led to many restrictions in daily life and protective health care actions in all hospitals to ensure basic medical supply. This questionnaire-based study among spinal surgeons in central Europe was generated to investigate the impact of coronavirus disease 2019 (COVID-19) and consecutively the differences in restrictions in spinal surgery units. METHODS: An online survey consisting of 32 questions on the impact of the COVID-19 pandemic and the related restrictions on spinal surgery units was created. Surgical fellows and consultants from neurosurgical, orthopedic, and trauma departments were included in our questionnaire-based study with the help of Austrian, German, and Swiss scientific societies. RESULTS: In a total of 406 completed questionnaires, most participants reported increased preventive measurements at daily clinical work (split-team work schedule [44%], cancellation of elective and/or semielective surgeries [91%]), reduced occurrence of emergencies (91%), decreased outpatient work (45%) with increased telemedical care (73%) and a reduced availability of medical equipment (75%) as well as medical staff (30%). Although most physicians considered the political restrictive decisions to be not suitable, most considered the medical measures to be appropriate. CONCLUSIONS: The COVID-19 pandemic resulted in comparable restrictive measures for spinal surgical departments in central Europe. Elective surgical interventions were reduced, providing additional resources reserved for severe acute respiratory coronavirus 2-positive patients. Although similar restrictions were introduced in most participants' departments, the supply of personal protective equipment and the outpatient care remained insufficient and should be re-evaluated intensively for future global health care crises.

Hemiarthroplasty of the hip using the direct anterior approach.

OBJECTIVE: Minimally invasive approach in total hip arthroplasty for the treatment of femoral neck fractures with a hemiarthroplasty. INDICATIONS: Femoral neck fractures of patients without hip osteoarthritis where the acetabulum is still intact. CONTRAINDICATIONS: Lesions and infections of the skin in the approach area; hip osteoarthritis; surgeon's lack of experience with the technique. SURGICAL TECHNIQUE: The direct anterior approach (DAA) uses the Smith-Peterson interval between the tensor fasciae latae (TFL) and the rectus and sartorius muscle. After coagulation of the ascending branches of the femoral circumflex vessels, the capsule is opened. The remaining parts of the femoral neck are removed and osteotomized if necessary. The femoral head is removed with a cork screw. Then the shaft is supported by 2 sharp retractors at the greater trochanter from cranial, and the leg is externally rotated, hyperextended, and adducted. A TFL release can be performed which we also recommend. The femoral canal is opened step by step and extended with rasps which are introduced with the double curved broach handle. Cement and the final implant are introduced and after the trial reduction also the final head. The hip is reduced, the capsule adapted and the wound closed. POSTOPERATIVE MANAGEMENT: For this approach, there are no approach specific recommendations. Postoperative treatment depends on whether the approach was extended with muscle releases and on the type of reconstruction performed. If the approach was limited to the minimally invasive direct anterior portal, quicker rehabilitation can be expected due to the reduced muscle damage. We prefer mobilization with full weight bearing as tolerated on the next day.