Comparison of medial distal tibial angle in EOS imaging and weightbearing X-ray.

BACKGROUND: The medial distal tibial angle (MDTA) is used for measurement of ankle alignment. Standard to measure MDTA is weightbearing mortise view. EOS imaging becomes more popular for limb alignment analysis using low-dose radiation. As MDTA might vary in EOS, comparison between both radiographic techniques has been performed. METHODS: MDTA was compared between both techniques in 43 cases by defining the mechanical tibial axis in different ways (X-ray low, EOS low, EOS high). For each method MDTA, intra- and interobserver reliability has been compared. RESULTS: The correlation between the different methods were measured by ICC (intraclass coefficient) and were ICC 0.86 (X-ray low/EOS low), ICC 0.85 (X-ray low/EOS high) and ICC 0.97 (EOS low/EOS high). Intra- and interobserver reliability were in each case ICC > 0.95. CONCLUSION: ICC showed a substantial to excellent agreement between all methods. EOS is appropriate to determine MDTA and can be used for assessment of coronar deformities of the distal tibia.

[Custom made total knee arthroplasty : Review of current literature]. / Der individuelle bikondyläre, kreuzbanderhaltende Oberflächenersatz am Kniegelenk : Aktuelle Literaturübersicht.

Custom-designed total knee replacement has become a standard procedure in some orthopaedic centres worldwide. Due to the lack of literature, the discussion about the hypothetical advantages has remained controversial. It was the aim of this study to focus on the current literature on custom-made total knee arthroplasty. We can demonstrate that custom-made total knee arthroplasty is a reproducible strategy with good clinical results in terms of leg-axis reconstruction, natural kinematics, patient-related outcomes and cost effectiveness. This has led to the fact that the Orthopaedic Data Evaluation Panel (ODEP) of the National Health Service in Great Britain rated the Conformis custom-designed knee replacement in 2017 with a 3D rating.

[Adult acquired flatfoot deformity-operative management for the early stages of flexible deformities]. / Der erworbene Plattfuß des Erwachsenen ­ Operative Therapie der flexiblen Deformität im frühen Stadium.

Flexible adult acquired flatfoot deformity includes a wide spectrum of fore- and hindfoot pathologies and remains a complex clinical challenge. Clinical history, inspection and accurate physical examination are paramount for diagnosis. Early stages of flexible adult acquired flatfoot deformity present with increased hindfoot valgus and medial arch collapse. Operative management typically consists of an open medializing calcaneal osteotomy and an augmentation of the insufficient posterior tibial muscle using a flexor digitorum longus tendon transfer. New surgical techniques and a deeper understanding of pathophysiology may change traditional treatment pathways.

Comparison of the Manchester-Oxford Foot Questionnaire (MOXFQ) and the Self-Reported Foot and Ankle Outcome Score (SEFAS) in patients with foot or ankle surgery.

BACKGROUND: Patient-reported outcome measures are a critical tool in evaluating the efficacy of orthopedic procedures. The intention of this study was to compare the psychometric properties of the Manchester-Oxford Foot Questionnaire (MOXFQ) and the Self-Reported Foot and Ankle Outcome Score (SEFAS) in patients with foot or ankle surgery. METHODS: 177 patients completed both scores and FAOS, Foot and Ankle Outcome Score (FAOS), Short Form 36 (SF-36) and numeric scales for pain and disability (NRS) before and after surgery. Test-Retest reliability, internal consistency, floor and ceiling effects, construct validity, responsiveness and minimal important change were analyzed. RESULTS: The MOXFQ and SEFAS demonstrated excellent test-retest reliability with interclass correlation coefficient values >0.9 Cronbach's alpha (α) values demonstrated strong internal consistency. No floor or ceiling effects were observed for both questionnaires. As hypothesized MOXFQ subscales correlated strongly with corresponding SEFAS, FAOS and SF-36 domains. MOXFQ subscales showed excellent responsiveness between preoperative assessment and postoperative follow-up, whereas SEFAS demonstrated moderate responsiveness. CONCLUSIONS: The MOXFQ and SEFAS demonstrated good psychometric properties and proofed to be valid and reliable instruments for use in foot and ankle patients. MOXFQ showed better outcomes in responsiveness.

Reliability, validity and responsiveness of the German self-reported foot and ankle score (SEFAS) in patients with foot or ankle surgery.

BACKGROUND: Patient-reported outcome measures are a critical tool in evaluating the efficacy of orthopedic procedures and are increasingly used in clinical trials to assess outcomes of health care. The intention of this study was to develop and culturally adapt a German version of the Self-reported Foot and Ankle Score (SEFAS) and to evaluate reliability, validity and responsiveness. METHODS: According to Cross Cultural Adaptation of Self-Reported Measure guidelines forward and backward translation has been performed. The German SEFAS was investigated in 177 consecutive patients. 177 Patients completed the German SEFAS, Foot and Ankle Outcome Score (FAOS), Short-Form 36 and numeric scales for pain and disability (NRS) before and 118 patients 6 months after foot or ankle surgery. Test-Retest reliability, internal consistency, floor and ceiling effects, construct validity and minimal important change were analyzed. RESULTS: The German SEFAS demonstrated excellent test-retest reliability with ICC values of 0.97. Cronbach's alpha (α) value of 0.89 demonstrated strong internal consistency. No floor or ceiling effects were observed for the German version of the SEFAS. As hypothesized SEFAS correlated strongly with FAOS and SF-36 domains. It showed moderate (ES/SRM > 0.5) responsiveness between preoperative assessment and postoperative follow-up. CONCLUSION: The German version of the SEFAS demonstrated good psychometric properties. It proofed to be a valid and reliable instrument for use in foot and ankle patients. TRIAL REGISTRATION: DRKS00007585.

No difference between standard and high flexion cruciate retaining total knee arthroplasty: a prospective randomised controlled study.

PURPOSE: The purpose of this prospective, randomised, double-blind study was to test the hypotheses that patients with high-flexion total knee arthroplasty (TKA) have (1) a wider/greater range of motion (ROM) post-operatively and (2) higher levels of knee society score (KSS) and WOMAC score post-operatively compared to standard TKA. METHODS: In this study, 28 high flexion with 31 standard TKAs were compared. We measured ROM, pre-operatively, on day 3, 7, 28, and after 6 and 36 months post-operatively as well as KSS and WOMAC score pre-operatively, on day 28 and after 6 and 36 months post-operatively. RESULTS: No statistically significant differences were found between both groups with regard to the target parameters. The mean ROM was 113° (range 80°-140°, SD 13.4°) in the control group (standard TKA) and 117° (range 90°-140°, SD 12.3) in the study group (high-flexion TKA) at 36 months follow-up [p = not significant (n.s.)]. The KSS pre-operatively was 38.2 (range 8-64, SD 15.8) in the control group and 45.9 (range 8-74, SD 16.0) in the study group (n.s.) increasing to 157.6 in the control group and 156.7 in the study group (p = n.s) at 36 months follow-up. CONCLUSION: This study could not confirm significant benefits of high-flexion TKA compared to standard TKA with regard to ROM and higher levels of KSS and WOMAC score. LEVEL OF EVIDENCE: I.

The value of colour Doppler sonography of the knee joint: a useful tool to discriminate inflammatory from non-inflammatory disease?

OBJECTIVE: To determine the diagnostic value of colour Doppler ultrasound (CDUS) in patients with inflammatory arthritis (IA) vs non-inflammatory disease (e.g. OA) of the knee joint. METHODS: Standardized CDUS examinations were performed in 111 knee joints of 106 patients (70 women and 36 men) presenting with severe OA (n = 72) or confirmed IA (n = 39) of one or both knee joints to determine the degree of synovial inflammation in a semiquantitative fashion. To definitely distinguish inflammatory from non-inflammatory disease, SF was obtained from every patient within 24 h after sonography and analysed SFs containing ≤1000 white blood cells (WBC)/µl were considered non-inflammatory, whereas ≥5000 WBC/µl were classified as inflammatory. RESULTS: The CDUS sum score of OA patients was determined to be 3.3 (range 0-8). In contrast, IA patients exhibited significantly elevated synovitis score of 5.3 (range 3-9) (P < 0.001). However, high synovial CDUS activity could be observed in OA patients sporadically. Therefore, there is no definitive CDUS threshold that clearly separates OA from IA patients. CONCLUSION: CDUS is a valuable instrument to assist clinicians in distinguishing OA from IA of the knee joint, but nevertheless should always be interpreted within the clinical context.

Infusion, core decompression, or infusion following core decompression in the treatment of bone edema syndrome and early avascular osteonecrosis of the femoral head.

An increase in interstitial fluid is an expression of bone marrow edema (BME) and osteonecrosis (ON). The exact pathogenetic processes still remain unknown. Treatment options are mainly symptomatic with core decompression as surgical golden standard with immediate pain relief. Recently, it has been shown that intravenous iloprost can be used to achieve a reduction in BME and ON with a considerable improvement in the accompanying symptoms. The effect of intraveneously applied iloprost alone (12 patients) was studied against core decompression alone (12 patients) as well as iloprost following core decompression (12 patients). We could find a significant improvement in HHS, WOMAC score, SF-36 score and VAS 3 months and 1 year after therapeutical intervention in all treatment groups; however, statistically best results were obtained by combination. Concerning the MRI scans, we found a distinct reduction in BME in all groups again favoring the combination. Concerning ON, the results were not as promising as for BME. Intravenous prostacyclin and core decompression as monotherapy are of efficient therapeutical benefit in the treatment of BME, and the combination of both methods, however, seems to be most promising, also in the treatment of ON. Long-term results and higher number of patients are needed for final statements.

Assessing patient-oriented results after revision total knee arthroplasty.

BACKGROUND: Revision total knee arthroplasties (TKA) have been performed with increasing frequency over the last 25 years. METHODS: In this study, we retrospectively analyzed 78 patients who underwent 78 revision TKAs during the years 2003­2007 with an average follow-up of 81 months (range 60­108 months). All patients were treated with a standard rotating hinge prosthesis (TC3, DePuy, Warsaw, IN, USA) due to significant instability. We evaluated the postoperative results using the Knee Society clinical rating system and the WOMAC rating system. RESULTS: Clinical results revealed significant improvements in both scores. Complications occurred in almost one-third of the cases, with a reoperation rate of 26 %. CONCLUSION: Our mid-term findings show that revision TKAs lead to an improvement in patient-perceived outcomes of physical variables. While revision TKA is a useful option for patients, procedure-associated complications should not be neglected. During the course of the procedure, it is important to collect patient-oriented data and focus on responsive and valid scores.

A minimally invasive approach for total hip arthroplasty does not diminish early post-operative outcome in obese patients: a prospective, randomised trial.

PURPOSE: The benefits of minimally invasive surgical techniques in total hip arthroplasty (THA) are well known, but concerns about applying those techniques in obese patients are controversial. We prospectively compared patients with increased body mass index (BMI ≥ 30) undergoing THA with normal weight patients. METHODS: A total of 134 patients admitted for unilateral THA were randomised to have surgery through either a transgluteal or a minimally invasive approach (MicroHip). In each group a BMI ≥ 30 was used to define obese patients. Pre- and early post-operative demographics, intraoperative data, baseline haematological values, hip function (Harris Hip Score, Oxford Hip Score) and quality of life (EQ-5D) were assessed with follow-up at three months. RESULTS: Duration of surgery, blood loss, C-reactive protein levels, radiographic measurements and complication rates were comparable in all groups. There was a tendency for lower serum creatine kinase levels in the MicroHip group. Intraoperative fluoroscopic time and dose area products were significantly elevated in patients with a BMI exceeding 30 regardless of the approach used. Time points of mobilisation, length of hospital stay and functional outcome measurements were similar in the different weight groups. CONCLUSIONS: Our data suggest that obese patients gain similar benefit from MicroHip THA as do non-obese patients. The results of this study should be further investigated to assess long-term survivorship.

Comparing navigation-based in vivo knee kinematics pre- and postoperatively between a cruciate-retaining and a cruciate-substituting implant.

PURPOSE: Individual physiological knee kinematics are highly variable in normal knees and are altered following cruciate-substituting (PS) and cruciate-retaining (CR) total knee arthroplasty (TKA). We wanted to know whether knee kinematics are different choosing two different knee designs, CR and PS TKA, during surgery using computer navigation. METHODS: For this purpose, 60 consecutive TKA were randomised, receiving either CR (37 patients) or PS TKA (23 patients). All patients underwent computer navigation, and kinematics were assessed prior to making any cuts or releases and after implantation. Outcome measures were relative rotation between femur and tibia, measured medial and lateral gaps and medial and lateral condylar lift-off. RESULTS: We were not able to demonstrate a significant difference in femoral external rotation between either group prior to implantation (7.9° CR vs. 7.4° PS) or after implantation (9.0° CR vs. 11.3° PS), both groups showed femoral roll-back. It significantly increased pre- to postoperatively in PS TKA. In the CR group both gaps increased, the change of the medial gap was significantly attributable to medial release. In the PS group both gaps increased and the change of the medial and of the lateral gap was significant. Condylar lift-off was observed in the CR group during 20° and 60° of flexion. CONCLUSION: This study did not reveal significant differences in navigation-based knee kinematics between CR and PS implants. Femoral roll-back was observed in both implant designs, but significantly increased pre- to postoperatively in PS TKA. A slight midflexion instability was observed in CR TKA. Intra-operative computer navigation can measure knee kinematics during surgery before and after TKR implantation and may assist surgeons to optimise knee kinematics or identify abnormal knee kinematics that could be corrected with ligament releases to improve the functional result of a TKR, whether it is a CR or PS design. Our intra-operative finding needs to be confirmed using fluoroscopic or radiographic 3D matching after complete recovery from surgery.

A prospective cluster trial to increase antibiotic prescription quality in seven non-ICU wards.

Aim: To evaluate general shortcomings and faculty-specific pitfalls as well as to improve antibiotic prescription quality (ABQ) in non-ICU wards, we performed a prospective cluster trial. Methods: An infectious-disease (ID) consulting service performed a prospective investigation consisting of three 12-week phases with point prevalence evaluation conducted once per week (=36 evaluations in total) at seven non-ICU wards, followed by assessment of sustainability (weeks 37-48). Baseline evaluation (phase 1) defined multifaceted interventions by identifying the main shortcomings. Then, to distinguish intervention from time effects, the interventions were performed in four wards, and the 3 remaining wards served as controls; after assessing effects (phase 2), the same interventions were performed in the remaining wards to test the generalizability of the interventions (phase 3). The prolonged responses after all interventions were then analyzed in phase 4. ABQ was evaluated by at least two ID specialists who assessed the indication for therapy, the adherence to the hospital guidelines for empirical therapy, and the overall antibiotic prescription quality. Results: In phase 1, 406 of 659 (62%) patients cases were adequately treated with antibiotics; the main reason for inappropriate prescription was the lack of an indication (107/253; 42%). The antibiotic prescription quality (ABQ) significantly increased, reaching 86% in all wards after the focused interventions (502/584; nDf=3, ddf=1,697, F=6.9, p=0.0001). In phase 2 the effect was only seen in wards that already participated in interventions (248/347; 71%). No improvement was seen in wards that received interventions only after phase 2 (189/295; 64%). A given indication significantly increased from about 80% to more than 90% (p<.0001). No carryover effects were observed. Discussion: ABQ can be improved significantly by intervention bundles with apparent sustainable effects.

[Our path to electronic patient files]. / Unser Weg zur elektronischen Patientenakte.

Digitization in hospitals is developing rapidly. The aim of many tools is to save time and better interlink interprofessional teams. Digitization also harbors dangers which, in the best-case scenario, can be identified and resolved in good time. This article describes the path of an orthopedic department in the context of a maximum-supply clinic to electronic patient files.

[Treatment of Achilles insertional calcific tendinosis using a longitudinal midline incision approach/central tendon splitting approach]. / Therapie der kalzifizierten Insertionstendinopathie der Achillessehne über einen transtendinösen Zugang.

OBJECTIVE: Treatment of Achilles insertional calcific tendinosis through a longitudinal midline incision approach with optional resection of the retrocalcaneal bursa and calcaneal tuberosity (Haglund's deformity). INDICATIONS: Calcific Achilles tendinosis, dorsal heel spur, insertional tendinosis. CONTRAINDICATIONS: General medical contraindications to surgical interventions. Fracture, infection. SURGICAL TECHNIQUE: Longitudinal skin incision medial of the Achilles tendon. Exposure and midline incision of the Achilles tendon with plantar detachment from the insertion site preserving medial and lateral attachment. Resection of a dorsal heel spur and intratendinous calcifications. Optional resection of the retrocalcaneal bursa and calcaneal tuberosity (Haglund's deformity). POSTOPERATIVE MANAGEMENT: Partial weight bearing 20 kg in 30° plantar flexion in a long walker boot for 2 weeks. Afterwards 2 weeks of progressively weight bearing in 15° plantar flexion and another 2 weeks in neutral ankle joint position in a long walker boot. RESULTS: A total of 26 feet of 26 patients with calcific Achilles tendinosis were treated with midline incision of the tendon. In all feet calcific tendon parts were resected. In 10 (38%) feet, a prominent dorsal spur was resected, in 12 feet (38%) retrocalcaneal bursa, and in 24 (92%) feet a calcaneal tuberosity. Mean follow-up was 34.5 months (range 2-64 months). Preoperative Manchester-Oxford Foot Questionnaire (MOXFQ) score was 58.2 (±8.1) and postoperatively the score was 22.75 (±6.0). In all, 7 (26.9%) patients stated delayed wound healing; 1 suffered from deep vein thrombosis. Shoe problems were reported by 50% of patients, and 23.1% suffered from par- or dysesthesia. No revision surgery was required.

CRP and leukocyte-count after lumbar spine surgery: fusion vs. nucleotomy.

BACKGROUND: Despite the fact that C-reactive protein (CRP) levels and white blood cell (WBC) count are routine blood chemistry parameters for the early assessment of wound infection after surgical procedures, little is known about the natural history of their serum values after major and minimally invasive spinal procedures. METHODS: Pre- and postoperative CRP serum levels and WBC count in 347 patients were retrospectively assessed after complication-free, single-level open posterior lumbar interlaminar fusion (PLIF) (n = 150) for disc degeneration and spinal stenosis and endoscopically assisted lumbar discectomy (n = 197) for herniated lumbar disc. Confounding variables such as overweight, ASA classification, arterial hypertension, diabetes mellitus, and perioperative antibiotics were recorded to evaluate their influence on the kinetics of CRP values and WBC count postoperatively. RESULTS: In both procedures, CRP peaked 2-3 days after surgery. The maximum CRP level was significantly higher after fusion: mean 127 (SD 57) (p < 0.001). A rapid fall in CRP within 4-6 days was observed for both groups, with almost normal values being reached after 14 days. Only BMI > 25 and long duration of surgery were associated with higher peak CRP values. WBC count did not show a typical and therefore interpretable profile. CONCLUSION: CRP is a predictable and responsive serum parameter in postoperative monitoring of inflammatory responses in patients undergoing spine surgery, whereas WBC kinetics is unspecific. We suggest that CRP could be measured on the day before surgery, on day 2 or 3 after surgery, and also between days 4 and 6, to aid in early detection of infectious complications.

[Plantar fascia release and decompression of the first branch of the lateral plantar nerve (Baxter's nerve)]. / Plantarfaszienrelease und Dekompression des ersten kalkanearen Astes des Nervus plantaris lateralis (Baxter-Nerv).

OBJECTIVE: Treatment of chronic plantar fasciitis and release of the first calcaneal branch of the lateral plantar nerve (Baxter's nerve). INDICATIONS: Chronic plantar fasciitis, compression of the first calcaneal branch of the lateral plantar nerve (Baxter's nerve). CONTRAINDICATIONS: General medical contraindications to surgical interventions, infection. SURGICAL TECHNIQUE: Longitudinal incision at the medial heel. Exposure of the plantar fascia at its origin on the medial plantar calcaneus. Medial incision of the plantar fascia preserving the lateral portion. Resection of a heel spur, if present. Exposure of the abductor hallucis muscle. Incision of the superficial fascia of the muscle. Retraction of the muscle belly und incision of the deep portion of the fascia, decompression of the nerve. POSTOPERATIVE MANAGEMENT: Two weeks partial weight bearing 20 kg in a healing shoe. Progressively weight bearing using a shoe with a stiff sole for another 4 weeks. RESULTS: A total of 32 feet of 27 patients with chronic plantar fasciitis and compression of the first branch of the lateral plantar nerve were treated with medial incision of the fascia and a nerve decompression. In 24 feet a calcaneal spur was resected. Mean follow-up was 25.6 months (12-35 months). Preoperative Manchester-Oxford Foot Questionnaire (MOXFQ) score was 52.5 (±9.0), postoperative MOXFQ score was 31.3 (±4.1). Six (18,8%) patients had same or more pain 6 weeks postoperatively.;8 (25%) patients stated minor complications like swelling, delayed wound healing, temporary hypoesthesia or pain while walking.

Isolated Arthroscopic Lateral Retinacular Release for Lateral Patellar Compression Syndrome.

INTRODUCTION: Evidence concerning the role of isolated lateral retinacular release (LRR) for lateral patellar compression syndrome (LPCS) dates back at least three decades. Appropriate indications, execution and outcomes still remain unclear and controversial. The present investigation analyzed the midterm result of isolated and arthroscopic LRR for LPCS in a cohort of patients who underwent such procedure at our institution. MATERIAL AND METHODS: Patients undergoing isolated arthroscopic LRR for LPCS were identified retrospectively from our electronic database. All procedures were performed by two experienced surgeons. Patients with bony and/or soft tissues abnormalities, patellofemoral instability, moderate to severe chondral damage were not included. Patients with previous surgeries were not included, as were those who underwent combined interventions. Clinical scores and complications were recorded. RESULTS: 31 patients were recruited in the present investigation. The mean follow-up was 86.0 ± 22.8 months. The mean age of the patients at the index operation was 34.2 ± 13.1 years. A total 55% (17 of 31) were women, and 58% (18 of 31) had involved the right knee. The mean hospitalization length was 3.5 ± 1.4 days. At a mean follow-up of 86.0 ± 22.8 months, the numeric rating scale (NRS) was 1.2 ± 0.8, the Kujala score was 91.3 ± 11.3, the Lysholm score was 93.1 ± 15.0, and the Tegner score was 5.0 ± 1.8. At the latest follow-up, 9 of 31 (29.0%) of patients experienced compilations. One patient (3.2%) had a post-operative hemarthrosis which was managed conservatively. Six patients (19.4%) reported a persistent sensation of instability, without signs of patellar dislocation or subluxation. One patient underwent an arthroscopic meniscectomy, and another patient an anterior cruciate ligament (ACL) reconstruction. CONCLUSION: isolated arthroscopic lateral retinacular release for lateral patellar compression syndrome is feasible and effective, achieving satisfying results at more than seven years following the procedure.

Leg axis correction with ConforMIS iForma (interpositional device) in unicompartmental arthritis of the knee.

Degeneration of the meniscus and the articular cartilage in unicompartmental osteoarthritis of the knee results in progressive deformity of the leg axis. It is the aim of this study to evaluate if a leg axis correction can be achieved by implanting a customised metallic interpositional device for the knee (ConforMIS iForma). Before and after implanting a ConforMIS iForma knee implant, a radiological analysis of the leg axis deviation in the frontal plane was performed prospectively in 27 patients by evaluating anteroposterior single-leg stance radiographs. We achieved a sufficient leg axis correction with an average correction of 3.8 degrees and an averaged small under-adjustment of 0.9 degrees by inserting the ConforMIS iForma interpositional knee implant. Apart from the primary treatment objective of articular surface restitution the ConforMIS iForma knee implant can be reliably used to correct axis deformity occurring with unicompartmental osteoarthritis of the knee.

Navigated cup implantation in hip arthroplasty.

BACKGROUND AND PURPOSE: Many studies have suggested that navigation-based implantation can improve cup positioning in total hip arthroplasty (THA). We conducted a systematic review and meta-analysis to compile the best available evidence, and to overcome potential shortcomings because of small sample sizes in individual studies. METHODS: The search strategy covered the major medical databases from January 1976 through August 2007, as well as various publishers' databases. The internal validity of individual studies was evaluated independently by 3 reviewers. We used random-effects modeling to obtain mean differences in cup angulation and relative risk (RR) of cup positioning outside Lewinnek's safe zone. RESULTS: Of 363 citations originally identified, 5 trials of moderate methodology enrolling a total of 400 patients were included in the analysis. Mean cup inclination and anteversion were not statistically significantly different between the conventional groups and the navigated groups. Navigation reduced the variability in cup positioning and the risk of placing the acetabular component beyond the safe zone (RR = 0.21, CI: 0.13-0.32). INTERPRETATION: Based on the current literature, navigation is a reliable tool to optimize cup placement, and to minimize outliers. However, long-term outcomes and cost utility analyses are needed before conclusive statements can be drawn about the value of routine navigation in THA.