Mobility of the lumbo-pelvic-hip complex (spinopelvic mobility) and sagittal spinal alignment - implications for surgeons performing hip arthroplasty.

INTRODUCTION: The optimal positioning of the hip prosthesis components is influenced by the mobility and balance of the spine. The present study classifies patients with pathology of the spino-pelvic-hip complex, showing possible methods of preventing hip dislocations after arthroplasty. HYPOTHESIS: Hip-Spine Classification helps arthroplasty surgeons to implant components in more patient-specific position. MATERIALS AND METHODS: The group of 100 patients treated with total hip arthroplasty. Antero-posterior (AP) X-rays of the pelvis in a standing position, lateral spine (standing and sitting) and AP of the pelvis (supine after the procedure) were analyzed. We analyzed a change in sacral tilt value when changing from standing to sitting (∆SS), Pelvic Incidence (PI), Lumbar Lordosis (LL) Mismatch, sagittal lumbar pelvic balance (standing position). Patients were classified according to the Hip-Spine Classification. Postoperatively, the inclination and anteversion of the implanted acetabular component were measured. RESULTS: In our study 1 A was diagnosed in 61% of all cases, 1B in 18%, 2 A in 16%, 2B in 5%. 50 out of 61 (82%) in group 1 A were placed within the Levinnek "safe zone". In 1B, 2 A, 2B, the position of the acetabular component was influenced by both the spinopelvic mobility and sagittal spinal balance. The mean inclination was 43.35° and the anteversion was 17.4°. CONCLUSIONS: Categorizing patients according to Hip-Spine Classification one can identify possible consequences the patients at risk. Pathology of the spino-pelvic-hipcomplex can lead to destabilization or dislocation of hip after surgery even though implanted according to Lewinnek's indications. Our findings suggest that Lewinnek safe zone should be abandoned in favor of the concept of functional safe zones.

Effect of Photobiomodulation Therapy on the Increase of Viability and Proliferation of Human Mesenchymal Stem Cells.

BACKGROUND AND OBJECTIVES: We have investigated how low intensity laser irradiation emitted by a multiwave-locked system (MLS M1) affects the viability and proliferation of human bone marrow mesenchymal stem cells (MSCs) depending on the parameters of the irradiation. STUDY DESIGN/MATERIALS AND METHODS: Cells isolated surgically from the femoral bone during surgery were identified by flow cytometry and cell differentiation assays. For irradiation, two wavelengths (808 and 905 nm) with the following parameters were used: power density 195, 230, and 318 mW/cm 2 , doses of energy 3, 10, and 20 J (energy density 0.93-6.27 J/cm 2 ), and in continuous (CW) or pulsed emission (PE) (frequencies 1,000 and 2,000 Hz). RESULTS: There were statistically significant increases of cell viability and proliferation after irradiation at 3 J (CW; 1,000 Hz), 10 J (1,000 Hz), and 20 J (2,000 Hz). CONCLUSIONS: Irradiation with the MLS M1 system can be used in vitro to modulate MSCs in preparation for therapeutic applications. This will assist in designing further studies to optimize the radiation parameters and elucidate the molecular mechanisms of action of the radiation. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Retraction Note: An evaluation of the potential consequences of drilling titanium and tantalum implants during surgery - a pilot study.

The authors have retracted this article [1] because it constitutes redundant publication [2].

Preoperative Ultrasonographic Assessment of the Anterior Pelvic Plane for Personalized Total Hip Replacement.

OBJECTIVES: Correct positioning of the acetabular component is a key factor in minimizing the risk of dislocation after total hip replacement (THR) surgery. A "safe" orientation of the cup is usually defined by 2 angles measured between its geometric axis and the anterior pelvic plane. However, in the current state-of-the-art approach to THR surgery, the intraoperative orientation of the anterior pelvic plane cannot be measured. Even less is known about the functional orientation of the pelvis, which determines the postoperative orientation of the cup during the patient's everyday activities. The aim of this article is to present an original approach to personalized THR surgery, in which the necessary measurements are done preoperatively without interfering with the surgical work flow, and the individual orientation of the cup is obtained without navigation using standard tools that are available in the operating room. METHODS: To quantify the effect of the anatomic conditions on the final orientation of the cup, we measured the orientation of the anterior pelvic plane in 43 patients scheduled for THR using a newly developed noninvasive method based on ultrasonography and mobile devices. RESULTS: Our results confirm a large variability of the pelvic orientation in both supine and standing positions. We further show how this variability affects the final position of the cup and discuss its consequences for the patient. Finally, we explore a few practical solutions for individualized cup placement, including our own approach, which is based on tilting of the operating table. CONCLUSIONS: In this work, we show that the common guidelines used today for cup implantation can only be effectively applied to a small portion of the population. In most cases, it is crucial that the orientation of the cup is readjusted for the particular anatomy of the individual patient.

Application of Navigated Ultrasound for Assessment of the Anterior Pelvic Plane in Patients With Degenerative Hip Diseases.

OBJECTIVES: Correct positioning of the acetabular cup is the key for successful total-hip replacement. In common clinical practice, the target alignment of the cup is defined with respect to the anterior pelvic plane. In patients with substantial anterior pelvic plane inclination, this condition may lead to inappropriate distribution of the load on the cup, as most of the forces exerted within the hip joint act along the vertical axis. With the known pelvic inclination, it is possible to readjust the position of the cup with respect to the individual posture of the patient. In this work, we present the first clinical evaluation of a new approach to measurement of the pelvic tilt angle using navigated ultrasound. METHODS: In our method, the ultrasound probe is tracked with an optical localizer implemented on a handheld mobile device. The method was tested by taking preoperative measurements from 20 patients with osteoarthritis in standing, sitting, and supine positions. RESULTS: The mean values of the measured angles were consistent with the corresponding results reported by other authors. CONCLUSIONS: Considering the noninvasiveness of the method and affordability of the hardware used in our system, it can be used in preoperative and postoperative measurements of pelvic orientation for supporting surgery planning and evaluation of treatment outcomes.

An evaluation of the potential consequences of drilling titanium and tantalum implants during surgery - a pilot study.

BACKGROUND: The aim of the study was to evaluate the potential consequences of drilling titanium alloy (Ti) and tantalum (Ta) implants. METHODS: During an in vitro study, four holes were made in each of two spatially porous trabecular implants: one Ta and the other Ti alloy (Ti-6Al-7Nb). The weight and the volume of particles produced during the drilling were then measured using a Radwag XA 110/2X (USA) laboratory balance. RESULTS: The loss of mass of the Ti and Ta implants was respectively 1.26 g and 2.48 g, and the volume of free particles was respectively 280 mm3 and 149 mm3. The particles were recovered after each stage. Despite the use of 5 µm filters, around 0.6% of the total implant mass from both implants was not recovered after drilling (roughly 2% of the mass of the particles created). CONCLUSION: It is technically difficult to make holes in Ti and Ta implants using standard surgical tools, and the process creates a significant amount of metal particles which cannot be removed, despite intensive flushing. This may have a potentially adverse influence on the survival of the implant and result in negative systemic consequences.

Two stage revision hip arthroplasty in periprosthetic joint infection. Comparison study: with or without the use of a spacer.

PURPOSE: The aim of this study was to compare two methods of two-stage surgery for PJI (periprosthetic joint infection) after THA (total hip arthroplasty): one with and one without the use of an antibiotic-loaded cement spacer. METHODS: This retrospective study was performed on 99 consecutive patients (99 hips) with a minimum follow-up of 24 months. Patients were divided into two groups: (1) in whom the operation was performed using a spacer, and (2) for whom a spacer was not used. RESULTS: For the whole cohort, the results improved between pre-operative and final follow-up. Recurrence of infection was found in nine out of 98 patients (9.2%) and was not significantly different between the two groups. Patients treated with a spacer had better functional improvement in the interim period, but the VAS score was better in the non-spacer group. The improvement in final function was better in the spacer group with regard to HHS, but not according to WOMAC score or VAS at final follow-up. CONCLUSION: The resection arthroplasty should be awarded particular consideration in cases of poor soft tissue quality, bone stock deficiency, when complications related to spacer use are expected or chances of new hip endoprosthesis implantation are low.

Anterior Cruciate Ligament Reconstruction Using the Transphyseal Technique in Prepubescent Athletes: Midterm, Prospective Evaluation of Results.

PURPOSE: To evaluate the efficacy, results, and complications of transphyseal technique of anterior cruciate ligament (ACL) reconstruction in prepubertal patients and to assess a possible influence of children's growth on the outcome. METHODS: Between 2005 and 2009, 22 (16 boys and 6 girls) prepubescent patients, Tanner stage 1 and 2, underwent ACL reconstruction and the follow-up 6, 12, and 24 months after surgery and after growth plate closure. The average age of the girls was 11.2 years, and of the boys, 12.3 years. The average follow-up period was 77.2 months. Clinical outcome was evaluated by Lysholm, Tegner, and International Knee Documentation Committee (IKDC) objective and subjective knee scores. Standard radiograms were performed for potential axial growing disturbance. RESULTS: The average follow-up period was 77.2 months (range, 54 to 102 months), and IKDC subjective scores changed from 58 (range, 44 to 69) before surgery to 87 (range, 86 to 87; P = .00) at 6 months, 93 (range, 88 to 97; P = .00) at 12 months, and 95 (range, 92 to -98; P = .5) at final examination. Lysholm score increased from 58 (range, 53 to 64) before surgery to 89 (range, 85 to 92; P = .00) at 6 months and 96 (range, 94 to 100; P = .00) at 12 months, 24 months (P = .9), and final examination (P = .8). Before injury, all patients were graded 7 on the Tegner scale. Nineteen athletes reached at least grade 7 and returned to the level of activity a mean of 9 months after the surgery. No patient had deformity or growth disturbances observed clinically. CONCLUSIONS: Arthroscopic-assisted transphyseal ACL reconstruction in prepubescent patient is a promising technique, provided that all technical details are respected. It gives excellent subjective and objective knee scores and provides a very good function of the knee joint in the midterm period with no or only minor effect on the leg length. The rate of growth after surgery did not influence the results. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Clinical evaluation of the shape of the suprascapular notch--an ultrasonographic and computed tomography comparative study: Application to shoulder pain syndromes.

The most common site of suprascapular nerve compression and injury is the suprascapular notch. The aim of this study was to assess the sensitivity and specificity of sonography in determining the type of suprascapular notch (SSN). Thirty randomized patients (60 upper extremities) underwent USG examination of the shoulder area. The results were further compared with three-dimensional reconstructions of the scapulae obtained through CT examination to place the SSNs within a fivefold classification. For identification of type I, the sensitivity was 73.3% and the specificity 97.8%. For identification of type III, the values was 96.9% and 85.7%, respectively. Type II was not found in USG examination. Discrimination between type IV and V was not possible. The mean distance between the line connecting the edges of the SSN and the skin was 38 mm in right-handed patients and 34 mm in ambidextrous subjects. Ultrasonographic examination of the SSN is characterized by high specificity for type I, and high sensitivity for type III SSN. Discrimination between type IV and V of the SSN is not recommended based on sonographic evaluation.

A randomized study of autologous conditioned plasma and steroid injections in the treatment of lateral epicondylitis.

PURPOSE: Chronic tendinopathy of lateral epicondyle of the humerus, commonly known as "tennis elbow" is one of the most frequent tendinopathies caused by recurrent overload of the muscle origins. The aim of the study was to assess the effectiveness of treating lateral epicondylitis (LE) with autologous conditioned plasma (ACP) and betamethasone injections, and to compare these methods over the course of a one year follow-up. METHODS: Patients were randomly placed into one of into two groups: 53 were treated with ACP, and 46 with 1 ml betamethasone injections and 2 ml of 1 % lignocaine. Both those groups were comparable in terms of initial DASH score. RESULTS: After six weeks and six months, the mean DASH score was significantly better in the betamethasone group, but was better in ACP group after one year. Full recovery (patients with no symptoms) at all time points was more common in the betamethasone group. A comparison of grouped DASH scores revealed more very good and good results in the ACP group after one year. More patients had pain symptoms related to injection in the ACP group than the betamethasone group. CONCLUSIONS: ACP therapy of LE allows better results to be obtained at 12 months. Betamethasone injections give more rapid improvement, but the therapeutic effect is longer lasting in the ACP group.

Metal debris concentrations in soft tissues adjacent to loosened femoral stems is higher in uncemented than cemented implants.

BACKGROUND: There are still many questions related to aseptic femoral stem loosening. Systemic and local immune responses to the implanted "foreign body" is one of the reasons for loosening. The purpose of the study was to measure metal ion concentration (Ti, Co, Cr, Mo, Ni, Al) around loosened femoral stems and compare their levels around uncemented and cemented implants. METHODS: This paper reports 50 hips operated for isolated stem loosening, in 50 patients at the mean age of 57 years (from 21 to 87). There were 25 cemented (Co,Cr29,Mo,Ni) and 25 uncemented (Ti, Al) stems. The mean follow-up from primary hip replacement to revision was 10.1 years (from 0.5 to 17). During the procedure, scar tissue around the stem was taken for analysis of metal ions. RESULTS: The concentrations of titanium and aluminium in soft tissues around uncemented loosened stems were higher than cemented ones (p < 0.001, p < 0.001 respectively). However, no statistically significant differences were observed between both types of stems in terms of ions of the metal of which cemented implants had been made of (Co, Cr, Mo, Ni). CONCLUSIONS: In soft tissue around a loosened stem, the concentrations of metal ions from implants are much higher in case of uncemented stems than of cemented ones. Metal ions from vitalium femoral heads were found around uncemented stems in similar values to cemented streams.

Primary rotating-hinge total knee arthroplasty: good outcomes at mid-term follow-up.

We evaluated the clinical and radiologic outcomes of primary knee replacements using a rotating-hinge knee prosthesis in 12 knees with a minimum follow-up of 10 years. Indications for the operation included gross joint destruction, significant axial deformities and contracture with a dysfunctional medial collateral ligament in all cases. The patients' WOMAC and Knee Society scores improved, and the use of mobility aids decreased. No loosening of implants was observed. Nonprogressive radiolucent lines were identified around three tibial components. Three patients required marginal wound excision with resuturing and thereafter healed uneventfully. With significant improvement in function, pain and range of motion, the rotating-hinge knee prosthesis can be used as a salvage device in patients with medial collateral ligament deficiency, contracture, and gross joint destruction.

One-stage total knee arthroplasty with pre-existing fracture deformity: post-fracture total knee arthroplasty.

The aim of the study was to assess the results of treating knee osteoarthrosis with total knee arthroplasty (TKA) after previous tibia and/or femur fractures resulting in axial limb deformities. Thirty-six knees (34 patients) were operated on. At the most recent follow-up, 4.8 years after surgery, all but one patient demonstrated an improvement in both clinical and functional KSS. This male patient required revision after 2 years. Improved range of motion was generally noted, especially extension, however, two patients with both tibia and femur fractures had worse results. TKA is an effective method of treatment for patients with arthrosis after a previous femur or tibia fractures. When deformity is severe semi-constrained or constrained, implants with extensions may be necessary.

Do gene expression changes in articular cartilage proteases of the synovial membrane correlate with expression changes of the same genes in systemic blood cells?

PURPOSE: The aim of our study was to find whether an injury of the knee joint tissues increases gene expression of selected hyaline cartilage degenerating enzymes such as matrix metaloproteinases (MMP) and aggreacaneses (Agg). METHODS: A total of 138 patients (81 female, 57 male) were admitted for knee arthroscopy with a mean age of 38.8 years. Full blood samples were collected preoperatively and synovium samples intraoperatively. Joint tissue lesions such as menisci, anterior cruciate ligament (ACL) and hyaline cartilage were estimated. Real time PCR with spectrophotometric analysis was performed. RESULTS: An ACL lesion was found in 56 patients, medial menisci (MM) in 65, and lateral menisci (LM) in five. Chondral lesions were estimated according to Outerbridge's grading system. In laboratory tests correlation between ACL tear and gene expression was seen except TIMP1 in serum (p < 0.05). In MM lesions MMP9, Agg2 elevation in serum was observed. LM lesions erased MMP13, MMP14 in serum and MMP8 in synovium. Chondral lesions revealed that many genes had higher expression in patients without hyaline degeneration. All of the gene expressions correlated between serum and synovium. CONCLUSION: An ACL lesion provokes elevation in expression of proteases genes, while the influence of other lesions remains elusive. Gene expression in synovium correlates with peripheral blood.

[Osteoarthritis: etiology, risk factors, molecular mechanisms]. / Osteoartroza: etiologia, czynniki ryzyka, mechanizmy molekularne.

Osteoarthritis is an incurable joint disease manifesting itself with gradually progressing degenerative changes, leading to premature motor disability. These changes mainly occur owing to an imbalance between the processes of degeneration and regeneration of articular cartilage structures. Until now many risk factors favoring the development of degenerative joint disease have been identified. These include age, weight, previously sustained traumas to joints, sports, sex and genetic predisposition. The latest scientific reports confirm that the pathogenesis of changes in osteoarthritic joints is complex and occurs on many levels. Enzymes belonging to the metalloproteinases family are mainly responsible for the degeneration of articular cartilage. Their activity is regulated by numerous pro-inflammatory cytokines, transcription factors and miRNA. A thorough analysis of all processes occurring in the afflicted joints needs to be carried out before effective therapeutic strategies can be developed.

Clinical assessment of the efficacy of SpineCor brace in the correction of postural deformities in the course of idiopathic scoliosis.

BACKGROUND: The objective of the study was to perform a clinical, comparative assessment of the degree of postural deformities before and after the treatment of idiopathic scoliosis in patients treated with SpineCor brace compared to the control group. MATERIAL AND METHODS: A group of 90 children with idiopathic scoliosis (including 74 girls) at the average age of 12.2 was subject to prospective observation. Average pre-treatment Cobb angle was 24.9° in the thoracic spine and 25.8° in the lumbar spine. The group actively treated with the SpineCor brace consisted of 45 children, while the control group consisted of the remaining 45 children with the natural course of the disease. RESULTS: Both groups did not differ significantly in terms of age, gender, height, body weight, Risser sign of skeletal maturity and baseline clinical and radiological parameters of scoliosis. Significant reduction of rib hump was observed upon 2-year SpineCor brace treatment (P=0.04) compared to the group treated by physiotherapy only (P=0.91). Similarly, improvement in lumbar prominence was observed in the actively treated group (P=0.009), with a trend towards worse results in the control group (P=0.07) In the group treated with the SpineCor brace, significant reduction in pectoral and hamstring muscle contractures as well as reduction in shoulder asymmetry and reduction in anterior and posterior vertical deviation were observed. CONCLUSIONS: Treatment using the SpineCor dynamic brace leads to a clinical improvement in posture, particularly to reduction in rib hump, lumbar prominence and muscular contractures.

More than 20 years of experience with Dega transiliac osteotomy in the treatment of dislocated hip joints in children with cerebral palsy.

Cerebral palsy in children, which is the result of a nonprogressing damage to the central nervous system, causes motor and posture disorders that change with age. The level of child activity correlates with the hip dislocation risk. It most often affects nonwalking patients and those with tetraparesis or oblique pelvis. The aim of the study was to assess the effectiveness and clinical value of Dega pelvic osteotomy with accompanying directional femoral bone osteotomy after minimum of 20 years from surgery of patients with cerebral palsy. The conducted research was retrospective and concerned the children operated at our Hospital. The assessment was carried out in 346 children with spastic hip during the years 1993-2000. The inclusion criteria were applied: unilateral dislocation of the hip, the observation period of at least 20 years, pelvic osteotomy by Dega method and combined with varus derotation femur osteotomy. The analysis involved fifteen patients. The follow-up period was minimum 20 years (20-27 years). The average migration percentage decreased from 88% down to 25%, and an improved range of mobility was observed in the operated joint after surgery. However, the range of mobility was again significantly reduced during the last control examination after a minimum of 20 years. In all hips, the degenerative joint disease was present. Pelvic transiliac osteotomy, according to Dega, with VDRO, ensures very effective correction of the deficit in femoral head coverage by the acetabulum in the upper, lateral and posterior parts. However, it does not prevent the development of the early degenerative disease of the joint.

Is the Synovium the First Responder to Posttraumatic Knee Joint Stress? The Molecular Pathogenesis of Traumatic Cartilage Degeneration.

OBJECTIVE: The aim of this study was to evaluate if a similar catabolic and inflammatory gene pattern exists between the synovium, hyaline cartilage, and blood of patients with the knee joint tissues and if one precedes the other. DESIGN: A total of fifty-eight patients (34 females and 24 males) with a mean age of 44.7 years (range, 18-75) underwent elective knee arthroscopy due to previously diagnosed pathology. Full blood samples were collected preoperatively from synovium and cartilage samples intraoperatively. Real time PCR with spectrophotometric analysis was performed. Following genes taking part in ECM (extracellular matrix) remodeling were selected for analysis: MMP-1, MMP-2, MMP-8, MMP-9, MMP-13, MMP-14, ADAMTS-4 (Agg1) and ADAMTS-5 (Agg2) proteases, TIMP-1, and TIMP-2 - their inhibitors - and IL-1 and TNF-α cytokines. RESULTS: Analysis revealed a strong and significant correlation between gene expression in synovial and systemic blood cells (p <0.05 for all studied genes) with ADAMTS-4, ADAMTS-5, IL-1, TNF-α and TIMP-2 expression most positively correlated with an R>0.8 for each. An analysis between chondrocytes and systemic blood gene expression shown no significant correlation for all genes. Bivariate correlation of International Cartilage Repair Society grading and genes expression revealed significant associations with synovial MMP-1, MMP-2, MMP-8, MMP-9, IL-1, TNF-α and TIMP-2. CONCLUSION: We suggest that the synovial tissue is the first responder for knee joint stress factors in correlation with the response of blood cells. The chondrocyte's genetic response must be further investigated to elucidate the genetic program of synovial joints, as an organ, during OA development and progression.

An Analysis of the Preoperative Factors, Spinopelvic Mobility and Sagittal Spinal Alignment in Pre-THA Patients.

Hip arthroplasty is a very effective medical procedure. The optimal positioning of the components and the functioning of the endoprosthesis are influenced, among other things, by the mobility and balance of the spine. The aim of the study was to analyze the factors influencing the mobility of the lumbar-pelvic-iliac complex (spinopelvic mobility) together with the assessment of sagittal spinal alignment in patients prior to THA (total hip arthroplasty). Patients who underwent hip replacement surgery due to advanced osteoarthritis of the hip were enrolled in the study (n = 103). The sociodemographic characteristics, BMI, radiological advancement of the degenerative disease, quality of life, and range of joint mobility were completed using a proprietary questionnaire, the EQ-5D-5L questionnaire, and a clinical examination. X-ray images were analyzed: AP of the pelvis standing up, lateral of the spine standing and sitting. Key parameters were measured as ∆SS-change in sacrum angle value when changing from standing to sitting position and pelvic incidence (PI)-lumbar lordosis (LL) mismatch-sagittal lumbar pelvic balance measured in standing position. The patients were assigned to the appropriate groups according to the Hip-Spine Classification: normal group: 1A (n = 65; 63.1%), abnormal groups: 1B (n = 17; 16.5%), 2A (n = 16; 15.5%), 2B (n = 5; 4.9%). A correlation was shown between the abnormal groups and the individual components of PROMs in the scope of the self-service and normal activities categories (EQ-5D and EQ-VAS). However, the strength of the relationship turned out to be moderate, and the remaining components of the survey were statistically insignificant. The remaining factors analyzed, i.e., age, BMI, the range of hip motion, the presence of contracture in the joint in a clinical examination, and the radiological advancement of osteoarthritis on the Tonnis scale, do not predict abnormal relationships between the spine and the pelvis in our patients waiting for THA. Therefore, further investigations are needed to evaluate the correlation between preoperative factors and the lumbar-pelvic-iliac complex in patients prior to planned hip arthroplasty.

Long-term results of cementless hip arthroplasty with ceramic-on-ceramic articulation.

PURPOSE: The goal of the study was to evaluate long-term results of hip arthroplasty in patients with ceramic-on-ceramic articulation. METHODS: The follow-up involved 220 primary total hip arthroplasty procedures (188 patients, 101 women and 87 men) after implantation of the Mittelmeier cementless hip endoprosthesis. The mean age of patients at surgery was 44.5 years and the mean follow-up was 19.6 years, with a minimum of 12.3 years. Dysplastic, idiopathic and post-traumatic coxarthrosis were the most frequent forms of degenerative hip changes. The Merle d'Aubigné and Postel classification, as modified by Charnley, was used for clinical evaluation. RESULTS: Very good results were obtained in 39.5 % of the patients, good results in 43.6 %, satisfactory results in 9.1 % and poor results in 7.8 %. Twelve-year survival for the whole prosthesis was 86.36 %, for the acetabulum 89.99 % and for the stem 91.36 %. CONCLUSIONS: Long-term results of hip arthroplasty using the Mittelmeier prosthesis are fairly encouraging with their low incidence of loosened prosthesis components after surgery.