[Rehabilitative technologies in patients after total endoprosthesis of lower limbs' major joints: scientometric analysis]. / Reabilitatsionnye tekhnologii u patsientov posle total'nogo endoprotezirovaniya krupnykh sustavov nizhnikh konechnostei: naukometricheskii analiz.

Dynamically developing sphere of physical and rehabilitative medicine raises an important issue on implementation of technologies with proven effectiveness to recover neuromuscular, skeletal and movement-related functions, activity and partipation of traumatological patients into rehabilitation practice. The aim of this review is the consistent information analysis and synthesis of evidence-based researches of current effective methods in the context of medical rehabilitation after endoprosthesis of lower limbs' major joints, as well as the provision of structured information that helps to influence on decision-making for doctors of physical and rehabilitative medicine and other professionals who take part in multidisciplinary interaction.

Rehabilitation Phases, Precautions, and Mobility Goals Following Total Hip Arthroplasty.

The prevalence of total hip arthroplasty (THA) for advanced hip osteoarthritis (OA) is both increasing and shifting toward a younger average age. However, THA alone does not typically normalize function in these patients. Postoperative rehabilitation is often recommended to optimize joint motion, strength, and function. To date, there are no peer-reviewed clinical practice guidelines for postoperative rehabilitation following THA. Thus, optimal postoperative rehabilitation requires consideration of the existing literature and clinical expertise. This review article summarizes current recommendations for postoperative management of THA, including phases of rehabilitation, postoperative hip precautions, the effect of rehabilitation setting and mode of delivery on postoperative outcomes, and gait mechanics.

Do hip resurfacing and short hip stem arthroplasties differ from conventional hip stem replacement regarding impingement-free range of motion?

Total hip joint replacement (THR) is clinically well-established. In this context, the resulting range of motion (ROM) is crucial for patient satisfaction when performing joint movements. However, the ROM for THR with different bone preserving strategies (short hip stem and hip resurfacing) raises the question of whether the ROM is comparable with conventional hip stems. Therefore, this computer-based study aimed to investigate the ROM and type of impingement for different implant systems. An established framework with computer-aided design 3D models based on magnetic resonance imaging data of 19 patients with hip osteoarthritis was used to analyse the ROM for three different implant systems (conventional hip stem vs. short hip stem vs. hip resurfacing) during typical joint movements. Our results revealed that all three designs led to mean maximum flexion higher than 110°. However, hip resurfacing showed less ROM (-5% against conventional and -6% against short hip stem). No significant differences were observed between the conventional and short hip stem during maximum flexion and internal rotation. Contrarily, a significant difference was detected between the conventional hip stem and hip resurfacing during internal rotation (p = 0.003). The ROM of the hip resurfacing was lower than the conventional and short hip stem during all three movements. Furthermore, hip resurfacing shifted the impingement type to implant-to-bone impingement compared with the other implant designs. The calculated ROMs of the implant systems achieved physiological levels during maximum flexion and internal rotation. However, bone impingement was more likely during internal rotation with increasing bone preservation. Despite the larger head diameter of hip resurfacing, the ROM examined was substantially lower than that of conventional and short hip stem.

Mechanical and Tribological Performance of HDPE Matrix Reinforced by Hybrid Gr/TiO2 NPs for Hip Joint Replacement.

Hip joint collapse is a very common health problem. Many cases need a joint replacement, so nano-polymeric composites are an ideal alternative solution. Due to its mechanical properties and wear resistance, HDPE might be considered a suitable alternative to frictional materials. The current research focuses on using hybrid nanofiller TiO2 NPs and nano-graphene with various loading compositions to evaluate the best loading amount. The compressive strength, modules of elasticity, and hardness were examined via experiments. The COF and wear resistance were evaluated via a pin-on-disk tribometer. The worn surfaces were analyzed based on 3D topography and SEM images. The HDPE samples with various compositions of 0.5%, 1.0%, 1.5%, and 2.0 wt.% filling content of TiO2 NPs and Gr (with a ratio of 1:1) were analyzed. Results revealed that hybrid nanofiller with a composition of 1.5 wt.% exhibits superior mechanical properties compared to other filling compositions. Moreover, the COF and wear rate decreased by 27.5% and 36.3%, respectively.

Evaluating the Mechanical and Tribological Properties of 3D Printed Polylactic-Acid (PLA) Green-Composite for Artificial Implant: Hip Joint Case Study.

Artificial implants are very essential for the disabled as they are utilized for bone and joint function in orthopedics. However, materials used in such implants suffer from restricted mechanical and tribological properties besides the difficulty of using such materials with complex structures. The current study works on developing a new polymer green composite that can be used for artificial implants and allow design flexibility through its usage with 3D printing technology. Therefore, a natural filler extracted from corn cob (CC) was prepared, mixed homogeneously with the Polylactic-acid (PLA), and passed through a complete process to produce a green composite filament suit 3D printer. The corn cob particles were incorporated with PLA with different weight fractions zero, 5%, 10%, 15%, and 20%. The physical, mechanical, and tribological properties of the PLA-CC composites were evaluated. 3D finite element models were constructed to evaluate the PLA-CC composites performance on a real condition implant, hip joints, and through the frictional process. Incorporating corn cob inside PLA revealed an enhancement in the hardness (10%), stiffness (6%), compression ultimate strength (12%), and wear resistance (150%) of the proposed PLA-CC composite. The finite element results of both models proved an enhancement in the load-carrying capacity of the composite. The finite element results came in line with the experimental results.

Evaluating the Performance of 3D-Printed PLA Reinforced with Date Pit Particles for Its Suitability as an Acetabular Liner in Artificial Hip Joints.

Off-the-shelf hip joints are considered essential parts in rehabilitation medicine that can help the disabled. However, the failure of the materials used in such joints can cause individual discomfort. In support of the various motor conditions of the influenced individuals, the aim of the current research is to develop a new composite that can be used as an acetabular liner inside the hip joint. Polylactic acid (PLA) can provide the advantage of design flexibility owing to its well-known applicability as a 3D printed material. However, using PLA as an acetabular liner is subject to limitations concerning mechanical properties. We developed a complete production process of a natural filler, i.e., date pits. Then, the PLA and date pit particles were extruded for homogenous mixing, producing a composite filament that can be used in 3D printing. Date pit particles with loading fractions of 0, 2, 4, 6, 8, and 10 wt.% are dispersed in the PLA. The thermal, physical, and mechanical properties of the PLA-date pit composites were estimated experimentally. The incorporation of date pit particles into PLA enhanced the compressive strength and stiffness but resulted in a reduction in the elongation and toughness. A finite element model (FEM) for hip joints was constructed, and the contact stresses on the surface of the acetabular liner were evaluated. The FEM results showed an enhancement in the composite load carrying capacity, in agreement with the experimental results.

A novel hip joint prosthesis with uni-directional articulations for reduced wear.

A novel polymer-on-metal hip joint prosthesis design that makes use of uni-directional articulations was developed and tested in this work. The new implant was tested using two polymer variants, virgin ultra-high molecular weight polyethylene (UHMWPE), and Vitamin E-infused highly crosslinked polyethylene (VEHXPE). The degrees of freedom of the ball-and-socket are reproduced by three cylindrical orthogonally-aligned articulations. This unconventional design leverages on the molecular orientation hardening mechanisms of the polyethylene and increased contact area to minimize wear. An experimental hip joint simulator was used to compare the gravimetric wear of the conventional ball-on-socket and the new implant. The new prosthesis including UHMWPE components produced a 78% reduction in wear, whereas the new prosthesis with VEHXPE components produced a 100% reduction in wear, as no measurable wear was detected. Machining marks on the acetabular cups of the new prosthesis were retained for both polyethylene variants, further demonstrating the low levels of wear exhibited by the new implants. Both polyethylene materials produced particles in the range of 0.1-1.0 µm, which are the most biologically active. Nonetheless, the extremely low wear rates are likely to induce minimal osteolysis effects. Furthermore, the novel design also offers an increase of more than 24% in the range of motion in flexion/extension when compared to a dual-mobility hip implant. A prototype of the prosthesis was implanted into a Thiel-embalmed human cadaver during a mock-surgery, which demonstrated high resistance to dislocation and the possibility of performing a figure of four position.

Efficacy of hydrated phospholipid polymer interfaces between all-polymer bearings for total hip arthroplasty.

Measurements of wear resistance and metal ion release are important for designing bearing couples or interfaces in total hip arthroplasty (THA). In this study, we investigated wear resistance and metal ion release of surface-modified metal-free all-polymer hip bearings, such as poly(ether-ether-ketone), (PEEK) on cross-linked polyethylene (PEEK-on-CLPE), with a hydrated gel-like surface layer, to propose an improved alternative to the conventional materials used to design THA bearings. The PEEK surface resulted in less metal ion release than the cobalt-chromium-molybdenum (Co-Cr-Mo) alloy surface owing to the lack of metal. The PEEK-on-CLPE bearing (6.33 mg/106 cycles) had lower wear (rate) than the bearing with Co-Cr-Mo alloy-on-CLPE (10.47 mg/106 cycles) under controlled laboratory conditions; the wear performance of the all-polymer hip bearings was further improved with hemi- or both-surface modified with a hydrated poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) layer (3.74 and 3.06 mg/106 cycles, respectively). The PMPC-grafted interface of PEEK-on-CLPE will be especially suitable for THA candidates. This study is of key importance for the design of lifelong THA and a better understanding of the limitations resulting from using PEEK. Further studies are necessary to evaluate the possibility of using this material in artificial hips.

Female reproductive factors and risk of joint replacement arthroplasty of the knee and hip due to osteoarthritis in postmenopausal women: a nationwide cohort study of 1.13 million women.

OBJECTIVES: Previous studies of the relationships between female reproductive factors and osteoarthritis (OA) have shown conflicting results. In this study, we aimed to explore the relationships between reproductive factors and joint replacement arthroplasty of the knee (TKRA) and hip (THRA) in a large nationwide population-based cohort of postmenopausal Korean women. METHODS: We included 1,134,680 subjects who participated in national health examinations in 2009 in the study. The study outcomes were incident THRA or TKRA due to severe hip or knee OA. The relationships between reproductive factors and THRA or TKRA were evaluated using a multivariable-adjusted proportional hazards model. RESULTS: During a mean follow-up duration of 8.2 years, 1,610 incident THRA cases and 60,670 incident TKRA cases were observed. Later age at menarche, longer breastfeeding, HRT and OC use were associated with increased risk of TKRA for severe knee OA, while later age at menopause and longer reproductive span were associated with decreased risk. With regard to THRA for severe hip OA, later menarche, longer breastfeeding, HRT more than 5 years, and OC use more than 1 year were associated with higher risk. The associations between reproductive factors and severe OA were more pronounced in underweight and younger subjects. CONCLUSION: We found that shorter estrogen exposure was associated with higher risk of TKRA due to severe knee OA, and such associations were more pronounced in underweight and younger subjects. The association between shorter estrogen exposure and THRA was not robust.

The working efficiency improvement strategies of ambulatory surgery center serving for hip / knee joint replacement / 中国实用护理杂志

In order to respond to the call of the National Health Commission to implement day surgery, this study elaborated the work process and the efficiency improvement strategies of hip and knee joint replacement in ambulatory surgery centre in foreign countries. It summarized the good points in process, summarized the management experience, combined with domestic conditions. It explored the key steps and matters needing attention related to the ambulatory surgery center of hip and knee joint replacement to provide reference for operating efficiency and speeding up the process of Enhanced Rehabilitation After Surgery in orthopedic field.

The effect of pre-operative high doses of methylprednisolone on pain management and convalescence after total hip replacement in elderly: a double-blind randomized study.

PURPOSE: The aim of the study was to assess whether administration of a single dose of methylprednisolone in the group patients above 65 years of age will be effective in complex analgesic management after total hip arthroplasty (THA). METHODS: Seventy-seven patients above 65 years old were double-blind randomized into two: the study and controls groups. Pre-operatively, the study group received as a single dose of 125 mg intravenous methylprednisolone, while the others saline solution as placebo. Peri-operatively, all the patients were administered opioid and nonopioid analgesic agents. We measured the levels of inflammatory markers (leukocytosis, C-reactive protein-CRP), pain intensity level (visual analog scale-VAS; numerical rating scale-NRS), the life parameters, and noted complications. RESULTS: Following administration of methylprednisolone were significantly lower levels of CRP on all the four post-operative days; leukocytosis on the second day; the VAS/NRS score at rest after six, 12, and 18 hours post-operatively, diminished the dose of parenteral opioid preparations (oxycodone hydrochloride), the duration of analgesia by peripheral nerve block was significantly higher as compared with the placebo group (p < 0.000001). No infectious complications were noted; there was one patient who developed post-operative delirium. CONCLUSION: A single dose of methylprednisolone significantly reduces the level of post-operative pain at rest on the day of THA in the group patients above 65 years of age, decreases the dose of opioid analgesic agents, and significantly decreases the level of inflammatory markers, without infectious processes.

Preoperative Chronic Pain as a Risk Factor for Early Postoperative Cognitive Dysfunction in Elderly Patients Undergoing Hip Joint Replacement Surgery: A Prospective Observational Cohort Study.

Background: Although major joint replacement surgery has a high overall success rate, postoperative cognitive dysfunction (POCD) is a common complication after anesthesia and surgery, increasing morbidity and mortality. Identifying POCD risk factors would be helpful to prevent and decrease the occurrence of POCD. We hypothesized that preoperative chronic pain increases the risk of POCD. Methods: A single-center, observational, prospective cohort study was conducted from January 2018 to March 2020. All consecutive elderly patients (>65 years) who underwent elective total hip arthroplasty or hemiarthroplasty with general anesthesia by the same surgeon were enrolled. The patients underwent neuropsychological testing preoperatively and at 7 days and 2 months after surgery. To determine POCD, a nonsurgical control group was recruited from the general community. Results: Of the 141 patients who finished the neuropsychological testing 7 days after surgery, 61 (43.2%) had preoperative chronic pain. Of the 61 patients, 17 (27.9%) developed POCD; of the 79 patients with no chronic pain, 10 (12.7%) had developed POCD by 7 days after surgery. Multivariate logistic regression analysis identified preoperative chronic pain as a risk factor of POCD assessed 7 days after surgery (odds ratio 6.527; P = 0.009). There was no significant difference in the POCD incidence 2 months after surgery between patients with and without preoperative chronic pain. Conclusion: Preoperative chronic pain was a risk factor of developing POCD within 7 days after surgery in elderly patients following hip joint replacement surgery. Clinical Trial Registration: [www.ClinicalTrials.gov], identifier [NCT03393676].

Experimental design of Al2O3/MWCNT/HDPE hybrid nanocomposites for hip joint replacement.

Fracture in the hip joint is a major and quite common health issue, particularly for the elderly. The loads exploited by the lower limbs are very acute and severe; in the femur, they can be several folds higher than the whole weight of the body. Nanotechnology and nanocomposites offer great potential in biomedical applications. The organic materials are more biocompatible. Mechanical properties like strength and hardness are challenging parameters which control the selection of a joint. HDPE in its pure form has been successfully used as a prosthetic foot (external) but failed as an implant material due to limited mechanical properties. High-density polyethylene thermoplastic polymer (HDPE) and multi-walled carbon nanotubes (MWCNT)/Nano-Alumina is selected as a potential material for a biomedical implant and its mechanical properties and biocompatibility have been discussed. HDPE/MWCNT/Alumina (Al2O3) nanocomposites have not been explored yet for prosthetic implants. These nanocomposites were prepared in this investigation in different compositions. Prepared material has been physiochemically characterized to check the morphology and the structure. MWCNTs enhanced hardness and elastic modulus of the HDPE. Optimization of the material composition revealed that hybrid composite with structure (2.4% Al2O3 and 0.6% MWCNT) exhibits better mechanical properties compared to other ratios with 3% MWCNTs and 5% MWCNTs. Thermal gravimetric analysis (TGA) dedicates that the percentage of crystallization has been increased to 6% after adding MWCNT to HDPE. The moisture absorption decreased to 90% with 5% MWCNT. Experimental results of Colorimetric assay (MTT) of a normal human epithelial cell line (1- BJ1) over Al2O3/MWCNT@HDPE showed <20% cytotoxic activity, proving its acceptance for medical use. HDPE/MWCNT/Al2O3 nanocomposites emerged as a candidate material for artificial joints.

Effects of edaravone on postoperative cognitive function in elderly patients undergoing hip joint replacement surgery: A randomized controlled trial.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is a complication of central nervous system in patients after surgery. Edaravone as a brain-protective agent may have protective effect on postoperative cognitive function. The study was designed to explore the effects of edaravone on postoperative cognitive function in elderly patients undergoing hip joint replacement surgery and potential mechanism. PATIENTS AND METHODS: Patients undergoing hip joint replacement surgery were randomly allocated into 2 groups: the edaravone group (group E) and the control group (group C). Group E received intravenous edaravone at a dose of 0.5 mg/kg after induction of anesthesia, while group C received normal saline. The cognitive function was evaluated with the Mini-Mental State Examination (MMSE) 1day before surgery,3 days and the 7 days after surgery. Patients' plasma samples were collected to detect the levels of S100ß protein (S100ß), interleukin-6 (IL-6), matrix metalloproteinase-9 (MMP-9), superoxide dismutase (SOD) and malondialdehyde (MDA) before the induction of anesthesia, at the end of surgery and on postoperative day 3. RESULTS: The MMSE scores in group E were higher than those of group C 3 days after surgery (25.98 ± 1.99 vs 24.86 ± 1.86, p = 0.003). There were remarkable rises (p < 0.05) in plasma IL-6, S100ßand MMP-9 levels at the end of surgery and on postoperative day 3 in the two groups, however, edaravone pretreatment could reduce these levels to a certain extent compared with group C (p < 0.05).In group E, the SOD concentration was higher at the end of surgery (16.03 ± 2.46U/ml vs. 13.65 ± 2.53U/ml, p = 0.0001), while the MDA level was lower on postoperative day 3 than those in group C (7.01 ± 2.37 nmol/ml vs. 11.34 ± 3.18 nmol/ml, p = 0.0001). CONCLUSION: The results indicated that preoperative intervention with edaravone may improve the postoperative cognitive function in elderly patients undergoing hip joint replacement surgery.

Reduced-dose computed tomography is the most accurate method to measure ceramic hip resurfacing cup version.

BACKGROUND: A precise assessment of cup version after hip resurfacing is generally requested, especially in clinical trials or in case of complications. AIMS: To identify which diagnostic imaging modality, between AP pelvis X-rays, the AP Pelvis CT Scout image and reduced-dose axial CT scan, is the most precise to assess cup version of an all-ceramic hip resurfacing implant in a first-in-human clinical trial. METHODS: We retrospectively assessed the cup version of the first 20 patients who underwent an experimental all-ceramic hip resurfacing on AP pelvis X-rays (0.8 mSv of radiation), AP pelvis CT scout images (0.016 mSv) and axial CT slices performed using a reduced dose protocol (0.3 mSv). The intra-observer and inter-observer reliabilities were calculated. RESULTS: Reduced dose Pelvis CT scan was the most precise imaging modality to detect cup version (Pearson Correlation Coefficient, PCC = 0.98, p < 0.001). The AP Pelvis CT Scout image was found to be sufficient to measure cup version within an acceptable margin of tolerance (mean difference ±â€¯4.7° from pelvis CT scan) and highly correlated to axial pelvis CT scan measurements (PCC 0.97, p < 0.001). Analysis of cup version from AP X-rays poorly correlated with measurements from Pelvis CT (PCC 0.59, p = 0.006). CONCLUSIONS: Due to lower radiation exposure and highest accuracy, reduced dose CT is a valid modality to measure acetabular cup version after ceramic hip resurfacing. Plain X-rays are not accurate nor precise to measure version, whereas high agreement of measurements between AP Pelvis CT Scout and axial pelvis CT scan was found.

The effect of femoral head size on edge loading in metal-on-metal hip joint replacement under dynamic separation conditions.

Edge loading that occurs in hip joint replacements due to dynamic separation of the joint bearings has been shown to cause severe wear for meal-on-metal bearings. In the present study, the multibody dynamics model for metal-on-metal (MoM) hip joints with a medial-lateral translational mismatch in the centers of rotation of the cup and head has been developed to predict the dynamic separation and contact force of edge loading under gait loading conditions. The effects of larger head diameters (28-55 mm), in combination with the translational mismatch (0-4 mm) and varied cup inclination angles (45°-65°), on edge loading of MoM bearings have been computationally investigated. For the given translational mismatch, increasing head diameters results in negligible effects on the dynamic separation, contact force and severity of edge loading. Increasing head size also leads to increased offset loading torque which has been found to reach at the level that may cause cup loosening under larger translational mismatch at 4 mm. The result highlights the importance of the cup inclination angle of 45° and a lower translational mismatch to avoid severe edge loading.

Effect of home visit intervention on joint function and life ability of patients after hip arthroplasty / 中国实用护理杂志

Objective@#To observe the effect of home visit on joint function and complications of patients undergoing hip replacement.@*Methods@#Ninety cases of patients with artificial hip replacement who were admitted to our hospital from January to December 2017 were randomly divided into two groups by random Number Table Method.45 patients in the control group were given routine nursing after discharge, and 45 patients in the observation group were treated with home visit nursing. The hip function and living ability of the two groups were evaluated 8, 12, 16 weeks after discharge,and the complication rate was compared.@*Results@#The self-care ability scores of the observation group at 8, 12 and 16 weeks after discharge were 102.23±11.20, 108.36±10.41, 116.25±10.36 higher than those of the control group at 97.86±10.35), 100.21±14.26, 104.23±15.6, with significant differences (t=1.922, 3.097, 4.294, P < 0.05 or 0.01). The Harris scores of the observation group at 8, 12 and 16 weeks after discharge were 82.31±11.27, 87.38±10.05, 95.10±11.23 higher than those of the control group at 78.02±10.23, 83.41±11.74, 89.43±11.62, with significant differences (t=1.891, 1.723, 2.343, P < 0.05). The incidence of complications in the observation group at 16 weeks after discharge was 0 lower than 13.33% (6/45) in the control group (χ2=6.429, P=0.011).@*Conclusions@#Home visit intervention can improve the self-nursing ability of the patients after hip joint operation, promote the recovery of hip function and life ability, and reduce the complications.

Effect of home visit intervention on joint function and life ability of patients after hip arthroplasty / 中国实用护理杂志

Objective To observe the effect of home visit on joint function and complications of patients undergoing hip replacement. Methods Ninety cases of patients with artificial hip replacement who were admitted to our hospital from January to December 2017 were randomly divided into two groups by random Number Table Method.45 patients in the control group were given routine nursing after discharge, and 45 patients in the observation group were treated with home visit nursing. The hip function and living ability of the two groups were evaluated 8, 12, 16 weeks after discharge,and the complication rate was compared. Results The self-care ability scores of the observation group at 8, 12 and 16 weeks after discharge were 102.23±11.20, 108.36±10.41, 116.25±10.36 higher than those of the control group at 97.86±10.35), 100.21±14.26, 104.23±15.6, with significant differences (t=1.922, 3.097, 4.294, P<0.05 or 0.01). The Harris scores of the observation group at 8, 12 and 16 weeks after discharge were 82.31± 11.27, 87.38±10.05, 95.10±11.23 higher than those of the control group at 78.02±10.23, 83.41±11.74, 89.43 ± 11.62, with significant differences (t=1.891, 1.723, 2.343, P < 0.05). The incidence of complications in the observation group at 16 weeks after discharge was 0 lower than 13.33% (6/45) in the control group ( χ2=6.429, P=0.011). Conclusions Home visit intervention can improve the self-nursing ability of the patients after hip joint operation, promote the recovery of hip function and life ability, and reduce the complications.

A computational parametric study on edge loading in ceramic-on-ceramic total hip joint replacements.

Edge loading in ceramic-on-ceramic total hip joint replacement is an adverse condition that occurs as the result of a direct contact between the head and the cup rim. It has been associated with translational mismatch in the centres of rotation of the cup and head, and found to cause severe wear and early failure of the implants. Edge loading has been considered in particular in relation to dynamic separation of the cup and head centres during a gait cycle. Research has been carried out both experimentally and computationally to understand the mechanism including the influence of bearing component positioning on the occurrence and severity of edge loading. However, it is experimentally difficult to measure both the load magnitude and duration of edge loading as it occurs as a short impact within the tight space of hip joints. Computationally, a dynamic contact model, for example, developed using the MSC ADAMS software for a multi-body dynamics simulation can be particularly useful for calculating the loads and characterising the edge loading. The aim of the present study was to further develop the computational model, and improve the predictions of contact force and the understanding of mechanism in order to provide guidance on design and surgical factors to avoid or to reduce edge loading and wear. The results have shown that edge loading can be avoided for a low range of translational mismatch in the centres of rotation of the cup and head during gait at the level of approximately 1.0 mm for a cup at 45° inclination, keeping a correct cup inclination at 45° is important to reduce the edge loading severity, and edge loading can be avoided for a certain range of translational mismatch of the cup and head centres with an increased swing phase load.