Prevention of Pernicious Vascular Event: Acetabular Component Screw Impinging on External Iliac Vessels - A Unique Case Report.

Introduction: Revision total hip arthroplasty requires meticulous planning and execution to achieve the desired outcome. Pelvic vessel injury following total hip arthroplasty is rare, but a well-known and serious complication, having a very high morbidity (15%) and mortality (7%). This case demonstrates the rare occurrence of acetabular screw abutment to the external iliac vessels, which if removed during revision hip surgery without releasing the adhesions around it, will lead to avulsion injury of the vessels and a catastrophic event. Case Report: We present this challenging and unique case of a 64-year-old female patient where the acetabular component screw was found to be adherent to the external iliac vessels, with vascular injury imminent. During revision surgery, the iliac vessels were first released free of all adhesions with the intrapelvis screw using an ilioinguinal incision and retroperitoneal approach. The prosthesis was removed using a posterior approach to the hip joint. Definitive surgery was performed after 2 weeks. Conclusion: Surgeons should be cognizant of the possibility of an avulsion vascular injury in revision cases having intrapelvic screws or implants. The proximity of such an implant with the intrapelvic vasculature must be confirmed preoperatively. Management should be individualized. Dual approach and staged procedure help in a favorable outcome. Vascular injury, revision total hip arthroplasty, screw abutting iliac vessel, external iliac vessel, computed tomographic angiography.

A larger sized cup accelerates cartilage erosion of acetabulum after bipolar hemiarthroplasty in elderly with femur neck fracture.

ABSTRACT: Bipolar hemiarthroplasty (BHA) is one of the common procedures done for the treatment of femur neck fracture. One of the frequently encountered complication with this surgery is erosion of the acetabular cartilage. This study was conducted to investigate acetabular erosion after BHA according to the difference in diameter between femoral head and implanted cup at minimum 10-year follow-up.We retrospectively reviewed 117 patients (117 hips) undergoing BHA with fracture of neck of the femur. Their mean age was 77.8 years (range, 65-96 years) and male: female ratio was 32:85. Patients were divided into 3 groups; Group A - bipolar cup size > actual head size, Group B - cup size < head size, Group C - cup size = head size. The degree of both superior and medial acetabular cartilage erosion was identified and calculated on postoperative radiographs using line of acetabular margin and Kohler line.The mean superior and medial acetabular erosion were 1.62 ±â€Š1.6 mm (range, 0-4.4) and 4.15 ±â€Š2.7 mm (range, 0-8.2) in Group A, 1.30 ±â€Š1.3 mm (range, 0-3.8) and 4.11 ±â€Š2.7 mm (range, 0-7.8) in Group B, and 0.90 ±â€Š1.1 mm (range, 0-2.6) and 3.16 ±â€Š2.9 mm (range, 0-7.9) in Group C (P = .039 and P = .187, respectively). The superior acetabular erosion showed significant difference between the 3 groups. During mean follow-up period of 12.3 years, 5 patients (5/117, 4.3%) underwent conversion to total hip arthroplasty due to superior acetabular erosion. All of 3 patient underwent BHA with a larger bipolar cup than the actual femoral head.A lager sized cup accelerated superior cartilage erosion of acetabulum after BHA. An optimal cup size should be considered when undergoing BHA in elderly patients.

Usefulness of Synthetic Osteoconductive Bone Graft Substitute with Zeta Potential Control for Intramedullary Fixation with Proximal Femur Nail Antirotation in Osteoporotic Unstable Femoral Intertrochanteric Fracture.

PURPOSE: This study was conducted in order to examine the usefulness of osteoconductive bone substitutes with zeta potential control (geneX® ds; Biocomposites, England) by comparing the complications and radiographic evaluation with or without geneX® ds augmentation for internal fixation with proximal femur nail antirotation (PFNA) for treatment of osteoporotic unstable intertrochanteric fractures. MATERIALS AND METHODS: A retrospective study of 101 patients who underwent fixation with PFNA in osteoporotic unstable intertrochanteric fractures was conducted from December 2015 to August 2020. The radiographic evaluation and complication rates were compared between patients with geneX® ds (Group A: 41 cases) and those without geneX® ds (Group B: 60 cases). RESULTS: In radiological valuation, the degree of blade sliding from the time immediately after surgery to one year after surgery was 1.4±1.2 mm and 5.8±2.7 mm in Group A and Group B, respectively (P<0.001). During the same time frame, a significant difference of 2.3±2.2° and 7.4±3.1° , respectively (P<0.001), in varus collapse, was observed for Group A and Group B. CONCLUSION: Among patients fixed with PFNA for treatment of unstable intertrochanteric fractures, less blade sliding and varus collapse was observed for those with geneX® ds augmentation compared to those without it. In addition, there was no increase in the incidence of complications. The authors believe it can be regarded as a safe and effective additive for intramedullary fixation for treatment of unstable intertrochanteric fractures.

Comparison of the postoperative analgesic effect for infiltration between the popliteal artery and the capsule of the posterior knee and that of periarticular multimodal drug injection in total knee arthroplasty: retrospective study in the immediate postoperative period.

BACKGROUND: The aim of this study is to compare the postoperative analgesic effect of infiltration between the popliteal artery and the capsule of the knee (IPACK) and the effect of periarticular multimodal drug injection (PMDI) in addition to adductor canal block (ACB) after total knee arthroplasty. METHODS: Among patients who received total knee arthroplasty from June 2017 to December 2017, 50 who underwent ACB with additional IPACK and 50 who received ACB with additional PMDI were selected for this study. We compared the postoperative pain numerical rating scale (NRS), the number of times patient-controlled analgesia was administered and the amount administered, the total amount of opioids given, and complications associated with the procedure between the two groups. RESULTS: NRS measured at rest and 45° knee flexion at days 1 and 2 after surgery was significantly lower in the IPACK group than in the PMDI group. The resting NRS measured at day 3 after surgery was also significantly lower in the IPACK group than in the PMDI group, and the NRS at 45° knee flexion measured from day 3 to day 5 showed a significant reduction in the IPACK group. No complications relating to the procedure occurred. CONCLUSIONS: IPACK may be a better option than PMDI for controlling acute phase pain in patients undergoing total knee arthroplasty.

Total Hip Arthroplasty: Past, Present, and Future. What Has Been Achieved?

In the 1960s, Sir John Charnley introduced to clinical practice his concept of low-friction total hip arthroplasty (THA). Although early designs were plagued by poor performance and even failure, there have been steady advances in implant designs, biomaterials, surgical techniques and an understanding of the biomechanical restoration of the hip; these advances have contributed to improvements in implant survival and clinical outcomes of THA in the past three decades. With improved wear resistance and mechanical reliability, a potential to last for at least 25 to 30 years are now available for THA. In this review, we focus on the evolution of THA and review current controversies and future directions of this procedure based on a single surgeon's 29-year of experience at a single institution.

Comparison of Functional Outcomes and Associated Complications in Patients Who Underwent Total Hip Arthroplasty for Femoral Neck Fracture in Relation to Their Underlying Medical Comorbidities.

PURPOSE: In patients with independent mobility, full hip range of motion and sufficient muscle strength for daily life without cognitive impairment, treatment of a femoral neck fracture with total hip arthroplasty (THA) may be a better option compared to bipolar hip hemiarthroplasty. Here, functional outcomes and complications in patients who underwent THA for femoral neck fracture based on their comorbidity status were analyzed. MATERIALS AND METHODS: Between January 2013 and December 2018, 110 patients were treated with THA for femoral neck fractures at our institution. These patients were retrospectively analyzed for clinical outcomes at final follow-up (mean=24.4 months, range: 6-81 months) using the Harris hip score (HHS) and the presence or absence of two potential comorbidities: i) diabetes mellitus (DM; 35 with and 75 without) and ii) hypertension (HTN; 50 with and 60 without). RESULTS: The incidence of superficial infections at the surgical site in patients with DM was significantly higher compared with patients without DM (P=0.024). There were no significant differences in other potential complications based on DM status. HHS at final follow-up between patients with and without DM and with and without HTN were not significantly different (83.3 vs. 81.0, P=0.39 and 81.6 vs. 82.4, P=0.75, respectively). CONCLUSION: Superficial infections occurred more frequently in patients with DM compared with patients without DM. DM and HTN status are not correlated with HHS.

Assessment of Korea's Orthopedic Research Activities in the Top 15 Orthopedic Journals, 2008-2017.

BACKGROUND: Bibliometrics is increasingly used to assess the quantity and quality of scientific research output in many research fields worldwide. This study aims to update Korea's worldwide research productivity in the field of orthopedics using bibliometric methods and to provide Korean surgeons and researchers with insights into such research. METHODS: Articles published in the top 15 orthopedic journals between 2008 and 2017 were retrieved using the Web of Science. The number of articles, citations and h-index (Hirsch index), funding sources, institutions, and journal patterns were analyzed. RESULTS: Of the total 39,494 articles, Korea's contribution accounted for 5.6% (2,161 articles), ranking fifth in the world in the number of publications. Korea ranked sixth (with 29,456) for total citations worldwide but ranked 17th (13.64) in terms of average citation per item and 14th (55) in terms of h-index. Korea showed the most prolific productivity in the field of sports medicine and arthroscopy. The institution that produced the highest number of publications was Seoul National University (n = 386, 17.9%). CONCLUSIONS: Orthopedic research in South Korea demonstrated high productivity in terms of the number of publications in high-quality journals between 2008 and 2017. However, total citations and average citations per article were still relatively low. Efforts should be made to increase citation rates for further improvement in research productivity in the field of orthopedics.

Pseudotumor and Subsequent Implant Loosening as a Complication of Revision Total Hip Arthroplasty with Ceramic-on-Metal Bearing: A Case Report.

Pseudotumors are not uncommon complications after total hip arthroplasty (THA) and may occur due to differences in bearing surfaces of the head and the liner ranging from soft to hard articulation. The most common causes of pseudotumors are foreign-body reaction, hypersensitivity and wear debris. The spectrum of pseudotumor presentation following THA varies greatly-from completely asymptomatic to clear implant failure. We report a case of pseudo-tumor formation with acetabular cup aseptic loosening after revision ceramic-on-metal hip arthroplasty. The patient described herein underwent pseudotumor excision and re-revision complex arthroplasty using a trabecular metal shell and buttress with ceramic-on-polyethylene THA. Surgeons should be aware of the possibility of a pseudotumor when dealing with revisions to help prevent rapid progression of cup loosening and implant failure, and should intervene early to avoid complex arthroplasty procedures.

Increased Serum Ion Levels After Ceramic-on-Metal Bearing Total Hip Arthroplasty: Influence of an Asian Lifestyle.

BACKGROUND: Recent clinical studies have suggested that systemic metal ion levels are significantly elevated at midterm follow-up in patients with ceramic-on-metal (COM) bearing. However, it is not clear whether there is a correlation between patient-related factors including the lifestyle and elevated levels of serum metal ions following COM total hip arthroplasty (THA). METHODS: Serum metal levels were measured in 201 patients (234 hips) including 121 COM patients (140 hips) and 80 non-COM patients (94 hips). The Harris Hip Score, University of California, Los Angeles activity scale score, and Western Ontario and McMaster Universities Osteoarthritis Index score were measured and radiographs were obtained for the analysis. RESULTS: Significantly higher levels of cobalt (Co) and chromium (Cr) were detected in the serum of the COM THA group (Co: 1.86 ± 4.0 µg/L; Cr: 1.81 ± 2.87 µg/L) than those of the non-COM THA group (Co: 0.27 ± 0.14 µg/L; Cr: 0.19 ± 0.25 µg/L; P < .001). The serum metal levels of patients who achieved the squatting position and the kneeling position were significantly higher than those of patients who could not squat (Co: P = .033; Cr: P = .074) and kneel (Co: P = .049; Cr: P = .031). The metal ion levels of the COM THA group correlated with the total range of motion (Co: P = .0293; Cr: P = .0399). CONCLUSION: Patients who underwent a 36-mm COM THA showed high serum metal levels although good clinical outcomes at the midterm follow-up. We found that COM THA patients who were capable of greater range of motion, squatting, and kneeling are at risk of metal ion-related problems.

Acetabular Defect Reconstruction with Trabecular Metal Augments: Study with Minimum One-year Follow-up.

PURPOSE: High rates of mechanical failure have been reported in type III acetabular defects. Recently porous trabecular metal augments have been introduced with, excellent biomechanical characteristics and biocompatibility, allowing early stability and greater bone ingrowth. The aim of the study was to assess the short term clinical and radiological outcome of the trabecular metal augments. MATERIALS AND METHODS: We performed, 22 revision total hip arthroplasties (THA) and 6 primary THA (total 28) using trabecular metal augments to reconstruct acetabular defect between 2011 to 2015. Among 28 patients, 18 were males, 10 females. Mean age of patients was 61.21 years. Paprosky classification for acetabular bone defects was used. Eighteen cases were classified as grade 3 A and 10 cases as grade 3B. Hip center was calculated in each case preoperatively and compared postoperatively to check whether it has been brought down. Clinical outcome assessed using Harris hip score (HHS) and radiological outcomes as osteolysis in acetabular zones and osseointegration, according to Moore's criteria. RESULTS: HHS improved from 58.00 to 86.20. Centre of rotation of hip joint corrected from 38.90 mm preoperatively to 23.85 mm postoperatively above the interteardrop line. Among 28 patients, 18 patients had three or more signs of osseointegration (Moore's criteria), during final follow up and 10 had one/two signs. No radiolucency, osteolysis, or loosening found during follow up radiographic examination. CONCLUSION: Our study showed that trabecular metal augments were highly satisfactory in short term. However, long term study is required for better evaluation.

Locking attachment plate fixation around a well-fixed stem in periprosthetic femoral shaft fractures.

INTRODUCTION: Periprosthetic fractures are difficult to manage. Plating technique has been considered a reliable form of management of periprosthetic fractures with a well-fixed stem, but a dependable and stable method of plate fixation to the bone is lacking. This study reports the clinical results using a locking attachment plate (LAP) instead of cable fixation to fix locking plates to a periprosthetic femoral shaft fracture. MATERIALS AND METHODS: Nineteen patients with periprosthetic femoral shaft fractures around well-fixed stemmed implants were studied between August 2012 and December 2014. Patients were followed up for at least 1 year postoperatively. Median age was 74 years (range 56-96 years). Fractures were classified according to the Unified Classification System, Vancouver classification, and Su classification. PROCEDURE: Open reduction was performed under minimal incision and the locking plate was fixed to the lateral cortex of the femoral shaft. The part of the shaft without a stem was fixed to the plate using 5.0-mm locking screws, and the part with an underlying stem was fixed using 3.5-mm locking screws through the LAP instead of cables. Postoperatively, patients were managed using general principles for femoral shaft fractures. RESULTS: Average follow-up was 16 months (range 12-36 months). All cases achieved fracture healing without loss of reduction. There were no cases of implant breakage or stem loosening at final follow-up. The average number of LAPs per fixation construct was 2.1 (range 1-4), and the average number of 3.5-mm locking screws through each LAP was 3.3 (range 2-4). The average value of plate screw density was 0.55 (range 0.37-0.8), and the average working length was four holes (range 2-8). CONCLUSIONS: Using the LAP to manage periprosthetic fractures with a well-fixed stem could obviate the need for cable around the stem area and yield acceptable outcomes.

Ganglion cyst of the hip mimicking lumbar disk herniation - A case report.

Sciatic nerve compression due to a ganglion cyst around the posterior aspect of the hip joint is not commonly described in literature. We report a rare case of a 63-year-old man with a ganglion cyst around his hip joint, who presented with symptoms of sciatica. After excision of the cyst, the patient was symptom free. A high index of clinical doubt and detailed clinical examination is required for non-palpable cystic lesions in close proximity to the sciatic nerve in patients presenting with symptoms of sciatica and in patients with concomitant of lumbar disk herniation.

Healing Process of Osteonecrotic Lesions of the Femoral Head Following Transtrochanteric Rotational Osteotomy: A Computed Tomography-Based Study.

BACKGROUND: Transtrochanteric rotational osteotomy (TRO) is a controversial hip-preserving procedure with a variable success rate. The healing process of femoral head osteonecrosis after TRO has been poorly explained till now. This study aimed to evaluate the healing process of previously transposed necrotic lesion after a TRO for nontraumatic osteonecrosis of the femoral head using computed tomography (CT). METHODS: Among 52 patients (58 hips) who had preserved original femoral head after TRO, we retrospectively reviewed 27 patients (28 hips) who had undergone sequential CT scans and had no major complication following TRO. The average age was 34 years (range, 18 to 59 years). The mean follow-up period was 9.1 years. We evaluated the reparative process of the transposed osteonecrotic lesion with CT scans. RESULTS: Plain radiographs of the osteonecrotic lesion revealed sclerotic and lucent changes in 14 hips (50%) and normal bony architecture in the other 14 hips (50%) at the final follow-up. CT scans of the osteonecrotic lesions showed cystic changes with heterogeneous sclerosis in 13 hips (46%), normal trabecular bone with or without small cysts in 9 hips (32%), and fragmentation of the necrotic lesion in 6 hips (22%). Seventeen hips (60%) showed minimal (13 hips) to mild (4 hips) nonprogressive collapse of the transposed osteonecrotic area. The collapse of the transposed osteonecrotic area on the CT scan was significantly associated with the healing pattern (p = 0.009), as all 6 patients (6 hips) with fragmentation of the necrotic lesion had minimal (5 hips) to mild (1 hip) collapse. Furthermore, a significant association was found between the collapse of the transposed osteonecrotic area on the CT scan of 17 hips (60%) and postoperative Harris hip score (p = 0.021). We observed no differences among the healing patterns on CT scans with regard to age, gender, etiology, staging, preoperative lesion type, preoperative intact area, percentage of necrotic area, direction of rotation and immediate postoperative intact area. CONCLUSIONS: The majority of the hips showed incomplete regeneration of the transposed osteonecrotic lesion with cysts, sclerosis, and fragmentation, whereas repair with normal trabecular bone was observed only in one-third of the hips that were preserved after Sugioka TRO.

Acetabular Reconstruction in Total Hip Arthroplasty.

The difficulties encountered in dealing with the bone deficient acetabulum are amongst the greatest challenges in hip surgery. Acetabular reconstruction in revision total hip arthroplasty can successfully be achieved with hemispherical components featuring a porous or roughened ingrowth surface and options for placement of multiple screws for minor acetabular defect. Acetabular component selection is mostly based on the amount of bone loss present. In the presence of combined cavitary and segmental defects without superior acetabular coverage, reconstructions with a structural acetabular allograft protected by a cage or a custom-made triflange cage have been one of preferred surgical options. The use of a cage or ring over structural allograft bone for massive uncontained defects in acetabular revision can restore host bone stock and facilitate subsequent rerevision surgery to a certain extent. But high complication rates have been reported including aseptic loosening, infection, dislocation and metal failure. On the other hand, recent literature is reporting satisfactory outcomes with the use of modular augments combined with a hemispherical shell for major acetabular defect. Highly porous metals have been introduced for clinical use in arthroplasty surgery over the last decade. Their higher porosity and surface friction are ideal for acetabular revision, optimizing biological fixation. The use of trabecular metal cups in acetabular revision has yielded excellent clinical results. This article summarizes author's experience regarding revision acetabular reconstruction options following failed hip surgery including arthroplasty.

Is two-stage reimplantation effective for virulent pathogenic infection in a periprosthetic hip? A retrospective analysis.

AIM: To investigate the effectiveness of two-stage reimplantation using antibiotic-loaded bone cement (ALBC) and the risk factors associated with failure to control periprosthetic joint infection (PJI). METHODS: We retrospectively reviewed 38 consecutive hips managed using two-stage reimplantation with ALBC. The mean follow-up period was 5.4 years (range: 2.5-9 years). RESULTS: The causative pathogens were isolated from 29 patients (76%), 26 of whom were infected with highly virulent organisms. Sixteen patients (42%) underwent at least two first-stage debridements. An increased debridement frequency correlated significantly with high comorbidity (P < 0.001), a lower preoperative Harris hip score (HHS; P < 0.001), antimicrobial resistance, and gram-negative and polymicrobial infection (P = 0.002). Of the 35 patients who underwent two-stage reimplantation, 34 showed no signs of recurrence of infection. The mean HHS improved from 46 ± 12.64 to 78 ± 10.55 points, with 7 (20%), 12 (34%), 11 (32%) and 5 (14%) patients receiving excellent, good, fair and poor ratings, respectively. CONCLUSION: The current study demonstrated that two-stage reimplantation could successfully treat PJI after hip arthroplasty. However, the ability of ALBC to eradicate infection was limited because frequent debridement was required in high-risk patients (i.e., patients who are either in poor general health due to associated comorbidities or harbor infections due to highly virulent, difficult-to-treat organisms). LEVEL OF EVIDENCE: Level IV.

A Rare Case of Femoral Neuropathy Associated with Ilio-Psoas Bursitis After 10 Years of Total Hip Arthroplasty.

We describe a case of femoral nerve palsy caused due to non-infective large iliopsoas bursitis after 10 years of cementless ceramic-on-metal THA. Bursectomy and exploration of femoral nerve were done to relieve the compressive symptoms of femoral nerve. Patient neurological symptoms were recovered within six months. Iliopsoas bursitis after THA can lead to anterior hip pain, lump in inguinal area or abdomen, limb swelling due to venous compression or more rarely neurovascular compressive symptoms depending on size and extension. Treating physician should be aware of this rare condition after THA in the absence of any radiographic findings so that prompt diagnosis and treatment can be carried out.

Radiologic healing of lateral femoral wall fragments after intramedullary nail fixation for A3.3 intertrochanteric fractures.

INTRODUCTION: Intramedullary nail fixation is a useful treatment option for A3 intertrochanteric fractures. Occasionally, we have encountered displaced lateral femoral wall (LFW) fragment during surgery with intramedullary nail system. We investigated the postoperative spontaneous reduction of displaced LFW fragments without further fixation and the factors that affected the spontaneous reduction of displaced LFW fragments. MATERIALS AND METHODS: Forty-four patients with A3.3 intertrochanteric fracture were treated by surgery using intramedullary nails (PFNA; Synthes, Paoli) between March 2007 and December 2012. All patients had a minimum follow-up period of 12 months. We calculated the amount of spontaneous reduction of the displaced LFW fragments from immediate postoperative and last follow-up anteroposterior radiographs. We measured the tilting angle of the LFW fragment, tip-apex distance (TAD), and telescoping of the blade, and evaluated the quality of postoperative reduction. RESULTS: Twenty-five of the 44 patients had displaced LFW fragments, and the average amount of spontaneous reduction of the displaced LFW fragment was 4.8 mm with statistical significance (p = 0.005). The average tilting angle of all patients was -4.97°, telescoping was 6.83 mm, and TAD was 19.77 mm. Twenty-one patients had good quality of reduction, 21 had acceptable quality, and 2 had poor quality. Multivariate logistic regression analysis for these factors indicated that tilting angle was the only significant factor related to spontaneous reduction of a displaced LFW fragment (p = 0.007, odds ratio = 1.336). CONCLUSIONS: In intramedullary nailing of A3.3 intertrochanteric fractures, the displaced LFW fragments tend to reduce spontaneously without any additional fixation during the postoperative period. We conclude that no additional fixation is needed for the displaced LFW fragment after surgery with intramedullary nail.

Management of Periprosthetic Hip Joint Infection.

Total hip joint replacement offers dramatic improvement in the quality of life but periprosthetic joint infection (PJI) is the most devastating complication of this procedure. The infection threatens the function of the joint, the preservation of the limb, and occasionally even the life of the patient due to long term hospitalization and high cost. For the surgeon it is a disastrous burden, which requires repeated, complicated procedures to eradicate infection and to provide a mobile joint without pain. Yet in the absence of a true gold standard, the diagnosis of PJI can be elusive. Synovial fluid aspiration, diagnostic imaging, traditional culture, peripheral serum inflammatory markers, and intraoperative frozen sections each have their limitations but continue to be the mainstay for diagnosis of PJI. Treatment options mainly include thorough irrigation and debridement with prosthesis retention, or a two-stage prosthesis exchange with intervening placement of an antibiotic-loaded spacer. Success in treating PJI depends on extensive surgical debridement and adequate and effective antibiotic therapy. Treatment in two stages using a spacer is recommended for most chronic PJI. Debridement, antibiotics and implant retention is the obvious choice for treatment of acute PJI, with good success rates in selected patients. This article presents an overview of recent management concepts for PJI of the hip emphasizing diagnosis and the clinical approach, and also share own experience at our institution.

Can pelvic tilting be ignored in total hip arthroplasty?

INTRODUCTION: The orientation of acetabular component is influenced by pelvic tilt, body position and individual variation in pelvic parameters. Most post-operative adverse events may be attributed to malposition of the component in the functional position. There is evidence that orientation of the pelvis changes from the supine to standing position. Authors report a case of recurrent dislocation after total hip arthroplasty due to excessive pelvic tilting. PRESENTATION OF CASE A 69-year old female with coxarthrosis had undergone total hip replacement with recurrent dislocation of the hip on bearing weight in spite of using constrained acetabular component. DISCUSSION: Our case report substantiates the influence of pelvic tilt, incurred by a sagittal deformity of spine, on dynamic orientation of the acetabular cup which was positioned in accordance with the anatomic landmarks alone. If the reference is only bony architecture and dynamic positions of the pelvis are not taken into account, improper functional orientation of the acetabular cup can result in sitting and standing positions. These can induce instability even in anatomically appropriately oriented acetabular component. CONCLUSION: The sagittal position of pelvis is a key factor in impingement and dislocation after total hip arthroplasty. Pelvic tilting affects the position of acetabular component in the sagittal plane of the body as compared with its anatomic position in the pelvis. We suggest a preoperative lateral view of spine-pelvis, in upright and supine position for evaluation of a corrective adaptation of the acetabular cup accordingly with pelvic balance.