Distinctiveness of Femoral and Acetabular Mesenchymal Stem and Progenitor Populations in Patients with Primary and Secondary Hip Osteoarthritis Due to Developmental Dysplasia.

Primary hip osteoarthritis (pOA) develops without an apparent underlying reason, whereas secondary osteoarthritis arises due to a known cause, such as developmental dysplasia of the hips (DDH-OA). DDH-OA patients undergo total hip arthroplasty at a much younger age than pOA patients (50.58 vs. 65 years in this study). Recently, mesenchymal stem and progenitor cells (MSPCs) have been investigated for the treatment of osteoarthritis due to their immunomodulatory and regenerative potential. This study identified cells in subchondral bone expressing common MSPC markers (CD10, CD73, CD140b, CD146, CD164, CD271, GD2, PDPN) in vivo and compared the proportions of these populations in pOA vs. DDH-OA, further correlating them with clinical, demographic, and morphological characteristics. The differences in subchondral morphology and proportions of non-hematopoietic cells expressing MSPC markers were noted depending on OA type and skeletal location. Bone sclerosis was more prominent in the pOA acetabulum (Ac) in comparison to the DDH-OA Ac and in the pOA Ac compared to the pOA femoral head (Fh). Immunophenotyping indicated diagnosis-specific differences, such as a higher proportion of CD164+ cells and their subsets in DDH-OA, while pOA contained a significantly higher proportion of CD10+ and GD2+ cells and subsets, with CD271+ being marginally higher. Location-specific differences showed that CD271+ cells were more abundant in the Fh compared to the Ac in DDH-OA patients. Furthermore, immunohistochemical characterization of stromal bone-adjacent cells expressing MSPC markers (CD10, CD164, CD271, GD2) in the Ac and Fh compartments was performed. This research proved that immunophenotype profiles and morphological changes are both location- and disease-specific. Furthermore, it provided potentially effective targets for therapeutic strategies. Future research should analyze the differentiation potential of subsets identified in this study. After proper characterization, they can be selectively targeted, thus enhancing personalized medicine approaches in joint disease management.

Complications of Percutaneous Vertebroplasty: A Pictorial Review.

Percutaneous vertebroplasty is a minimally invasive treatment technique for vertebral body compression fractures. The complications associated with this technique can be categorized into mild, moderate, and severe. Among these, the most prevalent complication is cement leakage, which may insert into the epidural, intradiscal, foraminal, and paravertebral regions, and even the venous system. The occurrence of a postprocedural infection carries a notable risk which is inherent to any percutaneous procedure. While the majority of these complications manifest without symptoms, they can potentially lead to severe outcomes. This review aims to consolidate the various complications linked to vertebroplasty, drawing from the experiences of a single medical center.

Novel micro-MRI approach for subchondral trabecular bone analysis in patients with hip osteoarthritis is comparable to micro-CT approach.

AIM: To test the agreement between a newly developed micro-magnetic resonance imaging (MRI) analysis of the subchondral bone and the micro-computed tomography (CT) approach. METHODS: Samples obtained from 10 patients with osteoarthritis undergoing total hip arthroplasty were scanned with a 7.0 T micro-MRI. Proton density-weighted images and proton density-weighted images with fat suppression were obtained. The results were validated with a micro-CT device. Micro-MRI and micro-CT scans of the same sample were aligned, and regions of interest were delineated on equal areas of the sample. Bone volume fraction was calculated by using in-house plugins. The agreement between the methods was tested with Bland-Altman analysis. RESULTS: The agreement between the methods was good, with average difference of 2.167%. The differences between the methods were not significant (P=0.272, t test). CONCLUSION: The novel micro-MRI approach could be used for subchondral bone analysis. With further optimization for clinical MRI machines, the approach can be also used in the diagnostics of hip osteoarthritis.

IMPACT OF CEMENTLESS ZWEYMÜLLER STEM ANTEVERSION ON RESISTANCE TO PERIPROSTHETIC FRACTURE IN TOTAL HIP ARTHROPLASTY.

Total hip arthroplasty implies proper orientation of both acetabular and femoral components with a range of 25-40° of combined anteversion. The aim of the study was to examine resistance to periprosthetic fracture of the axially loaded cross section rectangular femoral stem (Zweymüller) with respect to different degrees of anteversion, implanted in the artificial bone model, in laboratory conditions. Femoral bone models with implanted femoral stems were divided into 3 groups depending on the degree of stem anteversion (A, control group 13-17°; B, stem retroverted 0°-4°; and C, stem anteverted 26-30°). The amount of axial load leading to periprosthetic fracture (PPFx) of the artificial bone model was determined experimentally for each construct. The results showed that the load at which the PPFx occurred significantly increased with the increase of the endoprosthesis anteversion angle. In our clinical practice, we are often unable to place the acetabular component in an ideal grade of anteversion for intraoperatively determined reasons. The results of this experimental study suggested that increasing rectangular femoral (Zweymüller) stem anteversion lowered the risk of PPFx. This study was limited by experimental design (laboratory conditions, artificial bone) and should be clinically verified.

HIP ARTHROSCOPY: RESIDUAL CAM DEFORMITY COMBINED WITH LOOSE BONY FRAGMENT IN HIP CAPSULE.

Hip arthroscopy is a minimally invasive, effective and innovative orthopedic procedure with a relatively low rate of complications. In our patient, residual cam deformity and a bone fragment that remained in the front hip capsule after hip arthroscopy performed three years before caused thigh numbness, muscle fasciculations, and paresthesia. It was assumed that the loose bony fragment remained following burring on prior procedure. During hip flexion, neural structures were compressed and caused the mentioned symptoms. Revision hip arthroscopy was performed and the loose fragment in addition to residual cam deformity was removed. Resolution of pain and anterior thigh numbness was reported after the revision surgery.

Risk factors for subsidence of modular fluted tapered stem implanted by using transfemoral Wagner approach during revision hip arthroplasty.

PURPOSE: To determine clinical and radiographic risk factors for the vertical subsidence of modular fluted tapered stems implanted using the transfemoral Wagner approach in a cohort of revision hip arthroplasties. METHODS: A retrospective review of a single-centre surgical registry was performed. Patients who underwent a revision total hip arthroplasty, in which the uncemented modular fluted tapered stem (REVISION Hip/Anca-Ti6Al4V, LimaCorporate, Udine, Italy) was implanted using the transfemoral Wagner approach, were identified. Patient's demographic data, clinical and radiographic outcomes and post-operative complications were assessed. As a significant subsidence, a 5-mm cut-off was chosen. RESULTS: We identified 278 revision hip arthroplasties with a mean follow-up of 35 months. The median of subsidence in the group of 5 mm and less was 2 mm, and 17 mm in the group of subsidence of 5 mm and more. A negative correlation was found between the stem subsidence and the length of good contact between the medial and lateral cortical bone and the stem (medial, - 0.248; P < 0.001, lateral, 0.284; P < 0.001). For 200 mm stems, the percentage of good contact between femoral parts of stem and bone on medial side was 40.5% (81.0 mm) for patients with subsidence of five or less mm, and 30% (60.0 mm) for lateral side. For 140 mm stems, the percentage was 52.86% (74.0 mm) for medial side and 40.36% (56.5 mm) for lateral side. A neck length was shown to correlate significantly with the stem subsidence (P = 0.004). CONCLUSION: It is crucial to provide good contact between the bilateral cortical bone and stem, and, if possible, to select implant constructs with shorter femoral necks, in order to reduce subsidence and to ensure longer implant survivorship.

Current knowledge on the genetic background of developmental dysplasia of the hip and the histomorphological status of the cartilage.

Developmental dysplasia of the hip (DDH) represents a morphological abnormality characterized by the incongruity of femoral head and acetabulum. It ranges from mild dysplastic changes to complete dislocation. DDH has been associated with several hereditary and environmental risk factors, which could explain the incidence variability among different countries. Numerous genes may be involved in the disease etiology and progression. However, there are controversies in the literature regarding some of these genes. DDH-induced secondary osteoarthritis (OA) is characterized by changes in the macromolecule content of the cartilage and the expression of cartilage degradation markers. In addition, it exhibits a pattern of specific histological changes, with several reported differences between primary and DDH-induced secondary OA. The articular cartilage of patients with DDH shows specific radiological characteristics, including changes visible already in infancy, but also at pre-arthritic stages, early stages of OA, and in fully developed DDH-induced secondary OA. Although DDH has been extensively researched in different disease stages, the etiology of the disorder still remains uncertain. This review focuses on the current knowledge on the histomorphological status of the cartilage and the genetic background of DDH.

Applications and critical evaluation of fascia iliaca compartment block and quadratus lumborum block for orthopedic procedures.

Anterior section of the hip joint capsule is innervated by femoral nerve and obturator nerve, and posterior section is innervated by the nerve to quadratus femoris muscle and occasionally by the superior gluteal (posterolateral region) and sciatic nerve (posterosuperior region). One of the regional anesthesia options for hip surgery is the fascia iliaca compartment block (FICB) that affects nerves important for hip innervation and sensory innervation of the thigh - femoral, obturator and lateral femoral cutaneous nerve. FICB can be easily performed and is often a good solution for management of hip fractures in emergency departments. Its use reduces morphine pre-operative requirement for patients with femoral neck fractures and can also be indicated for hip arthroplasty, hip arthroscopy and burn management of the region. Quadratus lumborum block (QLB) is a block of the posterior abdominal wall performed exclusively under ultrasound guidance, with still unclarified mechanism of action. When considering hip surgery and postoperative management, the anterior QLB has shown to reduce lengthy hospital stay and opioid use, it improves perioperative analgesia in patients undergoing hip and proximal femoral surgery compared to standard intravenous analgesia regimen, provides early and rapid pain relief and allows early ambulation, thus preventing deep vein thrombosis and thromboembolic complications etc. However, some nerve branches responsible for innervation of the hip joint are not affected by QLB, which has to be taken into consideration. QLB has shown potential for use in hip surgery and perioperative pain management, but still needs to be validated as a reliable treatment approach.

Femoral head wear and metallosis caused by damaged titanium porous coating after primary metal-on-polyethylene total hip arthroplasty: a case report.

Excessive metal femoral head wear has been described only as revision surgery complication after primary ceramic-on-ceramic total hip arthroplasty (THA). Here, we present the first case of metal femoral head wear after primary metal-on-polyethylene THA. A 56-year-old woman was referred to our outpatient clinic 17 years after primary right-sided THA, experiencing pain and decreased right hip range of motion. Radiographic examination revealed acetabular cup dislocation, eccentric femoral head wear, damaged titanium porous coating of femoral stem, metallosis, and pseudotumor formation. Endoprosthetic components were extracted, but further reconstruction was impossible due to presence of large acetabular bone defect. Macro- and micro-structure of extracted components were analyzed. Acetabular liner surface was damaged, with scratches, indentations, and embedded metal debris particles present on the entire inner surface. Analysis of metal debris by energy-dispersive spectroscopy showed that it consisted of titanium and stainless-steel particles. Femoral head was gravely worn and elliptically shaped, with abrasive wear visible under scanning electron microscope. No signs of trunnionosis at head/neck junction were observed. Microstructure of femoral head material was homogeneous austenitic, with microhardness of 145 HV 0.2, which is lower than previously described titanium hardness. In conclusion, detached titanium porous coating of femoral stem can cause stainless-steel femoral head wear in primary metal-on-polyethylene THA. As soon as such detachment becomes evident, revision surgery should be considered to prevent devastating complications.

Influence of Fondaparinux Versus Nadroparin Calcium Thromboprophylaxis on Clinical Parameters Following Total Knee Arthroplasty

Fondaparinux has been shown to be as effective as low molecular weight heparin in orthopedic surgery, with no cases of heparin induced thrombocytopenia proven until today. The main goal of this prospective randomized controlled trial was to define whether thromboprophylaxis in patients with primary osteoarthritis of the knee undergoing total knee arthroplasty (TKA) influences clinical parameters in the same manner in patients receiving fondaparinux as in those receiving nadroparin during the first 7 postoperative days. Sixty patients with primary knee osteoarthritis underwent unilateral TKA performed by the same surgeon and were randomized into two groups of 30 patients receiving either fondaparinux or nadroparin thromboprophylaxis. Patients were compared according to the duration of operation, perioperative blood loss, laboratory results and clinical evaluation of the edema during the early postoperative period. No differences were found between the groups in the mean duration of surgery, perioperative blood loss, and most of laboratory results. The level of urea was significantly lower in the nadroparin group on the first and second postoperative day. No cases of heparin induced thrombocytopenia, deep vein thrombosis or pulmonary embolism were noted during the study. Study results showed both fondaparinux and nadroparin to have the same influence on clinical parameters during the first 7 postoperative days in patients undergoing TKA.

Pre-operative autologous blood donation versus no blood donation in total knee arthroplasty: a prospective randomised trial.

PURPOSE: During total knee arthroplasty (TKA) blood loss can be significant and in spite of all techniques for reducing blood loss there is still a significant possibility for blood transfusions. For blood loss management during TKA, pre-operative autologous blood donation (PABD) is still a standard of care. In this prospective randomised study we have evaluated the efficacy of PABD in patients undergoing TKA to answer the question whether there is any need for autologous blood donations during TKA and, if yes, for which group of patients. METHODS: Patients were randomised to three groups. In group 1 patients did not donate autologous blood, in group 2 patients donated 1 dose 72 hours prior to TKA and in group 3 patients donated autologous blood 14 days prior to TKA. In all patients haemoglobin, haematocrit, thrombocyte and reticulocyte values, iron concentrations (Fe, unsaturated iron binding capacity, total iron binding capacity), activated partial thromboplastin time, prothrombin time, and intra-operative and post-operative blood loss were measured and compared. RESULTS: With PABD there was no reduction in allogeneic blood transfusions and a large number of taken doses of autologous blood was discarded, which significantly increased the cost of treatment for these patients. For patients undergoing TKA, PABD can provoke iatrogenic anaemia and thereby increase the likelihood of the need for allogeneic blood transfusion. CONCLUSIONS: Results of our study showed that PABD in non-anaemic patients is not justified and is not economically feasible.

Failure of bulk bone grafts after total hip arthroplasty for hip dysplasia.

INTRODUCTION: Bulk bone grafts are used in total hip arthroplasty (THA) when adequate acetabular cup coverage cannot be achieved. Data from literature show mainly good short-term and mid-term results with contradictory long-term results. The aim of this study was to investigate acetabular cup stability and graft integrity after dysplastic adult hip reconstruction with total hip endoprosthesis and bulk bone graft for acetabular deficiency. METHODS: Seventy-two hips in 64 patients that underwent THA with bone autograft or allograft were assessed immediately after operation, 6 months and 1, 2, 3 and 10 years after operation. Acetabular angle, acetabular cup coverage, bone graft width, and bone graft height were measured and questionnaire was designed to determine acetabular cup stability and grade graft integrity. Four investigators graded grafts and inter-rater and intra-rater reliability of the questionnaire was tested. RESULTS: All measured parameters in all patients and in patients with autograft and those with allograft separately showed significant changes consistent with graft failure and acetabular cup instability when level of significance was set at p < 0.05. CONCLUSIONS: Results of this study show significant decrease in acetabular cup stability when either autograft or allograft is used for cemented acetabular reconstruction of dysplastic hip. Further, allografts showed twice as rapid failure as autografts. Although these results contradict both good short-term and long-term results in published literature, they present warning for future use of free bulk bone grafts in reconstructive hip surgery.

Treatment of postoperative pain after total hip arthroplasty: comparison between metamizol and paracetamol as adjunctive to opioid analgesics-prospective, double-blind, randomised study.

INTRODUCTION: Metamizole use has been limited because of its risk of agranulocytosis. However, more recent literature seems to support its safety. This prospective, randomised, double-blind study was conducted to compare the analgesic effects of intravenous metamizole or intravenous paracetamol in combination with morphine PCA during the first 24 h following total hip arthroplasty. MATERIALS AND METHODS: One hundred ten consecutive patients were selected for study. The two study groups were (A) metamizole, (B) paracetamol. Postoperative pain therapy was provided by Morphine PCA pump. In the first treatment group (A group), all patients received intravenous metamizole 1.5 g every 8 h during the first 24 postoperative hours. In the second treatment group (B group), all patients received intravenous paracetamol 1 g every 8 h during the first 24 postoperative hours. Postoperative pain intensity was measured 1, 2, 3, 4, 6, 8, 10, 14, 18, 22 h after the end of surgery by a VAS. RESULTS: Statistically significant differences in VAS pain values favoring metamizole were reported at 6-h (p = 0.038), 8-h (p = 0.036), 14-h (p = 0.011), 18-h (p < 0.001) and 22-h (p = 0.025) post-baseline. Mean cumulative pain values were 17.9 for metamizole and 30.6 for paracetamol. CONCLUSIONS: In this study, we have also shown excellent efficacy of paracetamol and metamizole combined with opioids, but metamizole proved to be a better analgesic than paracetamol. It is also necessary to mention the financial aspect considering that intravenous paracetamol is about ten times more expensive than an equivalent analgesic doses of intravenous metamizole.

Patient satisfaction after revision hip arthroplasty or resection hip arthroplasty due to periprosthetic infection.

In this retrospective study we have analysed 10-year period results of all type periprosthetic hip joint infection treatments at our Department. Data for 73 patients were analysed and functional status for 41 patients evaluated. A smaller proportion of patients (45%) with resection arthroplasty as the definitive solution were satisfied. These were mostly females with numerous comorbidities and lower functional demands. Much better results were achieved in 2-stage revision arthroplasty group. In conclusion whenever possible revision arthroplasty should be done because probability of re-infection is much lower than was previously believed, and the functional status of patients and their general life satisfaction is much higher.

Specificities in the Structure of the Cartilage of Patients with Advanced Stages of Developmental Dysplasia of the Hip.

Developmental dysplasia of the hip (DDH) presents varying degrees of femoral head dislocation, with severe cases leading to the formation of a new articular surface on the external side of the iliac bone-the neoacetabulum. Despite conventional understanding suggesting otherwise, a tissue resembling hyaline cartilage is found in the neoacetabulum and acetabulum of Crowe III and IV patients, indicating a potential for hyaline cartilage development without mechanical pressure. To test this theory, acetabular and femoral head cartilage obtained from patients with DDH was stained with hematoxylin-eosin and toluidine blue. The immunohistochemical analysis for collagen types II and VI and aggrecan was performed, as well as delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) analysis on a 7.0 T micro-MRI machine. The results obtained from DDH patients were compared to those of the control groups. Hyaline cartilage was found in the neoacetabulum and the acetabulum of patients with DDH. The nature of the tissue was confirmed with both the histological and the MRI analyses. The results of this study proved the presence of hyaline cartilage in patients with DDH at anatomical regions genetically predisposed to be bone tissue and at regions that are not subjected to mechanical stress. This is the first time that the neoacetabular cartilage of patients with advanced stages of DDH has been characterized in detail.

Measurement of safe acetabular medial wall defect size in revision hip arthroplasty with a porous cup.

INTRODUCTION: The majority of acetabular revisions can be performed with an uncemented, porous acetabular component with or without bone grafting. These are contained acetabular defects, with an intact acetabular rim (Paprosky type I and II). As defects of the medial wall of the acetabulum are a challenge situation revision surgery, we performed this biomechanical study on a pig pelvis model with contained acetabular defects to determine the size of medial wall defect at which the acetabular cup will have sufficient primary stability. MATERIALS AND METHODS: In 24 pig pelvis models, different diameter of medial wall defects were created, followed by acetabular component placement. The acetabulum externally loaded, and the force at a level in which the acetabular component remains stable for each diameter of defect, or at which point the acetabular cup moves into the pelvis for >2 mm. RESULTS: In the models with acetabular medial wall defects of 10 and 20 mm, 2 mm acetabular displacement occurred under a force between 1000 and 1500 N. In those with a medial wall defect of 25 mm, the force that caused acetabular instability was between 700 and 1000 N. In the models with 30 mm of medial wall defect all acetabular components were unstable under a force of 700 N. CONCLUSIONS: According to our results, acetabular component should be stable if the defect of the medial wall of the acetabulum is less than 68% of the diameter of the acetabular component or if the uncovered surface area of the acetabular component is not greater than 27%, and the force <700 N. For a load of 1000 N, the medial wall defect should not exceed 45% of acetabular component diameter or 18% of uncovered acetabular component surface.

Two different dosing regimens of human recombinant erythropoietin beta during preoperative autologous blood donation in patients having hip arthroplasty.

PURPOSE: Our aim was to evaluate the effectiveness of two different dosing regimens of human recombinant erythropoietin (rHu-EPO) for preoperative autologous blood collection in patients undergoing total hip arthroplasty (THA). METHODS: Prospective randomised trials in which erythropoietin 15,000 IU was administered intravenously twice a week or 30,000 IU once a week (total 90,000 IU) combined with ferrous II sulphate (Ferro-Gradumet 2) orally and compared with Ferro-Gradumet 2 alone. RESULTS: Although different dosing regimens of rHu-EPO administration during preoperative autologous blood donation have similar effects on the collection of two units of autologous blood, preoperative haemoglobin level and perioperative allogenic blood transfusion, a once weekly dose regimen of rHu-EPO was more convenient (although not statistically significantly) for patients. CONCLUSION: We recommend the more practical and comfortable but yet highly effective therapeutic regimen with a single weekly intravenous administration of rHu-EPO for patients scheduled for THA.

Previous corrective osteotomies of femur and pelvis are a risk factor for complications following total hip arthroplasty in hip dysplasia.

Background: Modified anatomy of dysplastic hips, bone defects and previous operations make THA (total hip arthroplasty) in patients with hip dysplasia a technically challenging procedure. Methods: One hundred and ten patients (mean 49.2 years of age, range 19-76, female:103, male:7) underwent 122 subsequent hip arthroplasties from 2012 to 2019. These patients were reviewed at least two years after THA. Plain radiography was used to determine Crowe classification of the affected hips. Fifty-three patients had an operation in childhood before THA was done (mean 47.0 years of age, standard deviation 8.3, range 19-62) and formed the "operated group". Among these patients, there were Chiari pelvic osteotomies, periacetabular osteotomies, femoral osteotomies, greater trochanter distalizations and soft tissue operations. Fifty-seven were not operated in childhood (mean 52.3 years of age, standard deviation 10.9, range 19-76) and formed the "non operated group". The functional status of the patients was assessed with the Oxford Hip Score (OHS). Results: 122 total hip arthroplasties were performed using uncemented femoral and acetabular components. There were 13 major complications identified. Ten were in the "operated group", of which 5 needed revision surgery. Only 3 were in the "non operated group", with no need for revision. Aseptic loosenings of the femoral component were seen in the patients that had femoral osteotomy done in childhood. Acetabular component migration and intrapelvic migration occurred due to the initial malposition and lack of osteointegration, thus requiring early revision after just 6 months. Other major complications were peroneal palsy, deep periprosthetic infection, severe trochanteritis and intraoperative femoral fracture. OHS was significantly higher in the "non operated group" 42.3 (10-48), opposed to 39.1 (10-48) in the "operated group" (p 0.017). Conclusion: Corrective osteotomies in childhood are a risk factor for complications and lower medium-term survivorship of the THA in hip dysplasia patients.

The neoacetabulum in developmental dysplasia of the hip is covered with hyaline cartilage.

The lack of adequate mechanical stimulation and appropriate contact between acetabulum and femoral head results with developmental dysplasia of the hip (DDH). In DDH, hip joint forms normally during the organogenesis, but deforms during the fetal development. Acetabulum remains comparable in width with normal acetabulum, but has increased length and decreased depth, resulting in a poor coverage of the femoral head. In cases of severe hip subluxation and luxation due to DDH, the femoral head articulates with the external side of the iliac bone, forming a neoacetabulum in the position that was genetically predetermined to become bony tissue. A neoacetabulum is therefore formed under intermittent mechanical pressure, but never has the depth of a physiological acetabulum due to different forces at this new location. Over time, the depth of the neoacetabulum increases, and a crest is formed that obstructs reposition of the femoral head into the anatomic acetabulum. We hypothesize that the neoacetabulum on the iliac bone in DDH patients is formed of hyaline cartilage, despite the lack of genetic predisposition for hyaline cartilage formation in this area. We assume that as the femoral head migrates during development in such patients, joint capsular tissue interposes between the external side of the iliac bone and the femoral head, and a cartilaginous metaplasia of the capsule follows. This results in elongation of the acetabular cartilage in the same direction as the femoral head migrated. This assumption is based on the finding that in patients with hip luxation such interposed joint capsule showed signs of cartilaginous transformation. Furthermore, in the inner part of such joint capsules, proteoglycan production was notably higher than that of other non-cartilaginous tissue. Also, high expression of cartilaginous genes, which are usually not expressed in this tissue, was observed. Confirmation of this hypothesis would put a new perspective on the pathogenesis of DDH and could lead to better management or even prevention of this condition.

Revision of Acetabular Component with a Debonded Porous Coating in an Elderly Patient.

Debonding of the porous coating from the acetabular component of a total hip endoprosthesis is a rare complication. Revision total hip arthroplasty for an unstable acetabular component with a debonded porous coating strongly fixed to the bone can be challenging, especially in elderly patients of poor overall health. In such patients, revision procedures should be as simple and safe as possible. We present our technique of solving that problem in a case of an 82-year-old female with bad general condition and unstable acetabular component of hip endoprosthesis. Because of extremely deficient bone stock, a well-fixed porous coating was left in acetabulum to serve as a "cage", allowing cemented acetabular component placement. This procedure can reduce the risk of intraoperative bone fracture, blood loss, and duration of surgery, which is important in elderly patients with poor overall health.