• The literature was reviewed to establish the levels of stem subsidence for both double and triple-tapered implants in order to determine whether there were any differences in subsidence levels with regard to the methods of measurement, the magnitude and rate of subsidence and clinical outcomes.

• All studies reporting subsidence of polished taper-slip stems were identified. Patient demographics, implant design, radiological findings, details of surgical technique, methods of measurement and levels of subsidence were collected to investigate which factors were related to increased subsidence.

• Following application of inclusion and exclusion criteria, 28 papers of relevance were identified. The studies initially recruited 3090 hips with 2099 being available for radiological analysis at final follow-up. Patient age averaged 68 years (42–70), 60.4% were female and the average body mass index (BMI) was 27.4 kg/m² (24.1–29.2).

• Mean subsidence at one, two, five and 10 years was 0.97 mm, 1.07 mm, 1.47 mm and 1.61 mm respectively. Although double-tapered stems subsided more than triple-tapered stems at all time points this was not statistically significant (p > 0.05), nor was the method of measurement used (p > 0.05).

• We report the levels of subsidence at which clinical outcomes and survivorship remain excellent, but based on the literature it was not possible to determine a threshold of subsidence beyond which failure was more likely.

• There were relatively few studies of triple-tapered stems, but given that there were no statistically significant differences, the levels presented in this review can be applied to both double and triple-tapered designs.

Cite this article: EFORT Open Rev 2021;6:331-342. DOI: 10.1302/2058-5241.6.200086

• Treatment of bacterial septic arthritis in the native adult hip joint can be challenging. Prompt diagnosis and treatment decisions can reduce the associated morbidity and mortality.

• For this systematic review of the literature, we asked: (1) What are the treatment options? (2) What are the success rates and the outcomes after treatment? (3) Which antibiotic and duration of therapy are optimal?

• We searched the electronic databases PubMed, Scopus, and Embase using the search terms “hip” or “native hip” and “septic arthritis” or “coxitis”. Studies were included if they reported on: (1) bacterial infection of the hip, (2) treatment, (3) success rate/outcomes, (4) follow-up. The final review included 19 studies. The quality of study reporting was evaluated with the Methodological Index for Non-randomized Studies (MINORS) questionnaire.

• Three treatment options are: arthroscopy, single open surgery, and two-stage total hip arthroplasty (THA). A high success rate in infection eradication was reported for all three. Intravenous antibiotic therapy should be promptly initiated to eradicate septic arthritis and minimize potential sequelae and complications.

• Arthroscopy, single open or two-stage THA were reported to be effective in treating bacterial septic arthritis of the native hip. The key to optimal outcome is early diagnosis and timely treatment.

Cite this article: EFORT Open Rev 2021;6:164-172. DOI: 10.1302/2058-5241.6.200082

• The aging of our society is associated with an increasing number of insufficiency fractures of the pelvis and the current standard of care is pain control and early mobilization. The aim of this study was to explore whether parathyroid hormone (PTH) treatment can support bone healing in these patients.

• We conducted a systematic review searching the databases PubMed, Embase and Cochrane. Our primary outcome was fracture healing, secondary outcome measures comprised pain, mobility and patient-reported outcome measures (PROMs).

• Eight articles were included in the qualitative synthesis, of which two were included in a meta-analysis. However, only three studies were comparative including one randomized controlled trial. Fracture healing and reported pain were assessed after eight weeks, and were significantly improved in the group being treated with PTH (p < 0.01) in the meta-analysis. All articles described a positive effect for PTH on fracture healing and pain.

• Our systematic review indicates that there is a positive effect of PTH treatment on healing and pain in patients with insufficiency fracture in the pelvic ring, but further research is necessary.

Cite this article: EFORT Open Rev 2021;6:9-14. DOI: 10.1302/2058-5241.6.200029

• When introducing an implant, surgeons are subjected to steep learning curves, which may lead to a heightened revision rate. Stepwise introduction revolutionized implant introduction but lacks a last step.

• No guidelines exist for the introduction of a well-documented implant not previously used in a department. This is problematic according to the European Union’s legislated tendering process, potentially leading to increased revisions. In this systematic review, the introduction of a well-documented total hip arthroplasty implant to experienced surgeons is explored amid concerns of higher revision rate.

• Literature search strategies were deployed in the Embase and Medline databases, revealing a total of 14,612 articles. Using the Covidence software (Cochrane, London), two reviewers screened articles for inclusion.

• No articles were found that fulfilled our eligibility criteria. A post hoc analysis retrieved two national register-based studies only missing information about the surgeon’s knowledge of the introduced implant. None of the introduced implants decreased the revision rate and around 30% of the introduced implants were associated with a higher revision rate.

• The review showed that no data exist about revision rates when introducing well-documented implants. In continuation thereof, the introduction of well-documented implants might also be associated with increased revision rates, as has been shown for total knee arthroplasty. We therefore suggest that special attention should be focused on changes of implants in departments, which can be achieved by way of specific registration in national registers.

Cite this article: EFORT Open Rev 2021;6:3-8. DOI: 10.1302/2058-5241.6.200047

• Parkinson’s disease (PD) poses a significant challenge for the arthroplasty surgeon, owing to excessive muscle tone, higher fracture risk and poor bone quality. Several studies have reported high mortality, early failure and perioperative complications associated with hip fracture surgery in PD; however, no higher-level evidence exists regarding elective hip arthroplasty.

• The aim of our study was to perform a systematic review to evaluate the evidence basis and clinical outcomes pertaining to patients with underlying Parkinson’s disease undergoing elective total hip arthroplasty (THA).

• We searched MEDLINE, EMBASE and The Cochrane Central Register of Controlled Trials to identify studies evaluating the safety and clinical outcomes of THA in patients suffering from Parkinson’s. Our review conforms to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

• Ten studies encompassing 49,730 patients were included in our systematic review. Qualitative synthesis demonstrated comparable results between PD patients and controls with respect to one-year mortality and surgical site infections. PD patients experienced more medical complications, had a longer hospital stay and worse long-term implant survival. Some studies also reported a higher rate of dislocation, periprosthetic fractures and aseptic loosening.

• Decisions about the optimal articulation, the utilization of cemented components, dual-mobility cups or constrained liners were not uniform among included studies.

• THA in patients with Parkinson’s disease can offer significant functional gains and pain relief. Surgical considerations pertain to the approach and ways to address instability, whereas emphasis should be placed on appropriate counselling and exploring whether potential improvement of life quality outweighs the risks.

Cite this article: EFORT Open Rev 2020;5:856-865. DOI: 10.1302/2058-5241.5.200034

• Robotic systems used in orthopaedics have evolved from active systems to semi-active systems.

• Early active systems were associated with significant technical and surgical complications, which limited their clinical use.

• The new semi-active system Mako has demonstrated promise in overcoming these limitations, with positive early outcomes.

• There remains a paucity of data regarding long-term outcomes associated with newer systems such as Mako and TSolution One, which will be important in assessing the applicability of these systems.

• Given the already high satisfaction rate of manual THA, further high-quality comparative studies are required utilizing outcome scores that are not limited by high ceiling effects to assess whether robotic systems justify their additional expense.

Cite this article: EFORT Open Rev 2020;5:866-873. DOI: 10.1302/2058-5241.5.200037

• Three-dimensional (3D) pre-operative planning in total hip arthroplasty (THA) is being recognized as a useful tool in planning elective surgery, and as crucial to define the optimal component size, position and orientation. The aim of this study was to systematically review the existing literature for the use of 3D pre-operative planning in primary THA.

• A systematic literature search was performed using keywords, through PubMed, Scopus and Google Scholar, to retrieve all publications documenting the use of 3D planning in primary THA. We focussed on (1) the accuracy of implant sizing, restoration of hip biomechanics and component orientation; (2) the benefits and barriers of this tool; and (3) current gaps in literature and clinical practice.

• Clinical studies have highlighted the accuracy of 3D pre-operative planning in predicting the optimal component size and orientation in primary THAs. Component size planning accuracy ranged between 34–100% and 41–100% for the stem and cup respectively. The absolute, average difference between planned and achieved values of leg length, offset, centre of rotation, stem version, cup version, inclination and abduction were 1 mm, 1 mm, 2 mm, 4°, 7°, 0.5° and 4° respectively.

• Benefits include 3D representation of the human anatomy for precise sizing and surgical execution. Barriers include increased radiation dose, learning curve and cost. Long-term evidence investigating this technology is limited.

• Emphasis should be placed on understanding the health economics of an optimized implant inventory as well as long-term clinical outcomes.

Cite this article: EFORT Open Rev 2020;5:845-855. DOI: 10.1302/2058-5241.5.200046

• The focus on taper corrosion in modular hip arthroplasty increased around 2007 as a result of clinical problems with large-head metal-on-metal (MoM) bearings on standard stems. Corrosion problems with bi-modular primary hip stems focused attention on this issue even more.

• Factors increasing the risk of taper corrosion were identified in laboratory and retrieval studies: stiffness of the stem neck, taper diameter and design, head diameter, offset, assembly force, head and stem material and loading.

• The high variability of the occurrence of corrosion in the clinical application highlights its multi-factorial nature, identifying the implantation procedure and patient-related factors as important additional factors for taper corrosion.

• Discontinuing the use of MoM has reduced the revisions due to metal-related pathologies dramatically from 49.7% (MoM > 32 mm), over 9.2% (MoM ⩽ 32 mm) to 0.8% (excluding all MoM).

• Further reduction can be achieved by omitting less stiff Ti-alloys and large metal heads (36 mm and above) against polyethylene (PE).

• Standardized taper assembly of smaller and ceramic heads will reduce the clinical occurrence of taper corrosion even further. If 36 mm heads are clinically indicated, only ceramic heads should be used.

• Taper-related problems will not comprise a major clinical problem anymore if the mentioned factors are respected.

Cite this article: EFORT Open Rev 2020;5:776-784. DOI: 10.1302/2058-5241.5.200013

• Choice of articulating materials, head size and the design of the articulation will become decisive for the long-term performance of a total hip arthroplasty (THA) and especially in terms of risk for dislocation and wear-related problems. Here we account for common alternatives based on available studies and the evidence that can be derived from them.

• Metal or ceramic femoral heads articulating against a liner or cup made of highly cross-linked polyethylene and ceramic-on-ceramic articulations have about similar risk for complications leading to revision, whereas the performance of metal-on-metal articulations, especially with use of big heads, is inferior. The clinical significance of problems related to ceramic-on-ceramic articulations such as squeaking remains unclear. With use of current technology ceramic fractures are rare.

• Large femoral heads have the potential to increase the range of hip movement before impingement occurs and are therefore expected to reduce dislocation rates. On the other hand, issues related to bearing wear, corrosion at the taper-trunnion junction and groin pain may arise with larger heads and jeopardize the longevity of THA. Based on current knowledge, 32-mm heads seem to be optimal for metal-on-polyethylene bearings. Patients with ceramic-on-ceramic bearings may benefit from even larger heads such as 36 or 40 mm, but so far there are no long-term reports that confirm the safety of bearings larger than 36 mm.

• Assessment of lipped liners is difficult because randomized studies are lacking, but retrospective clinical studies and registry data seem to indicate that this liner modification will reduce the rate of dislocation or revision due to dislocation without clear evidence of clinically obvious problems due to neck-liner impingement.

• The majority of studies support the view that constrained liners and dual mobility cups (DMC) will reduce the risk of revision due to dislocation both in primary and revision THA, the latter gaining increasing popularity in some countries. Both these devices suffer from implant-specific problems, which seem to be more common for the constrained liner designs. The majority of studies of these implants suffer from various methodological problems, not least selection bias, which calls for randomized studies preferably in a multi-centre setting to obtain sufficient power. In the 2020s, the orthopaedic profession should place more effort on such studies, as has already been achieved within other medical specialties, to improve the level of evidence in the choice of articulation when performing one of the most common in-hospital surgical procedures in Europe.

Cite this article: EFORT Open Rev 2020;5:763-775. DOI: 10.1302/2058-5241.5.200002

• Classical indications for hip preserving surgery are: femoro-acetabular impingement (FAI) (intra- and extra-articular), hip dysplasia, slipped capital femoral epiphysis, residual deformities after Perthes disease, avascular necrosis of the femoral head.

• Pre-operative evaluation of the pathomorphology is crucial for surgical planning including radiographs as the basic modality and magnetic resonance imaging (MRI) and/or computed tomography (CT) to evaluate further intra-articular lesions and osseous deformities.

• Two main mechanisms of intra-articular impingement have been described:

  • (1) Inclusion type FAI (‘cam type’).

  • (2) Impaction type FAI (‘pincer type’).

• Either arthroscopic or open treatment can be performed depending on the severity of deformity.

• Slipped capital femoral epiphysis often results in a cam-like deformity of the hip. In acute cases a subcapital re-alignment (modified Dunn procedure) of the femoral epiphysis is an effective therapy.

• Perthes disease can lead to complex femoro-acetabular deformity which predisposes to impingement with/without joint incongruency and requires a comprehensive diagnostic workup for surgical planning.

• Developmental dysplasia of the hip results in a static overload of the acetabular rim and early osteoarthritis. Surgical correction by means of periacetabular osteotomy offers good long-term results.

Cite this article: EFORT Open Rev 2020;5:630-640. DOI: 10.1302/2058-5241.5.190074