BACKGROUND:Large acetabular bone defects present a serious challenge in revision total hip arthroplasty. The off-label use of antiprotrusio cages in combination with tantalum augments is a promising treatment option in these difficult situations.METHODS:Between 2008 and 2013, 100 consecutive patients underwent acetabular cup revision with a cage-augment combination in Paprosky 2 and 3 defect types (including pelvic discontinuities). There were 59 patients available for follow-up. The primary endpoint was the explantation of the cage-and-augment construct. The secondary endpoint was acetabular cup revision for any reason. Also, radiographic and functional outcomes (Western Ontario and McMaster Universities Osteoarthritis Index, Harris Hip Score) were evaluated. Implant survival rates were determined using a Kaplan-Meier analysis. The significance level was set at P < .05.RESULTS:Explantation-free survivorship of the "Cage-and-Augment" system was 91.9% after a mean follow-up of 6.2 years (range, 0 to 12.8). All 6 explantations were due to periprosthetic joint infection (PJI). The overall revision-free implant survival rate was 85.7%, including 6 additional liner revisions due to instability. In addition, 6 early PJI occurred, which were successfully treated with debridement, irrigation, and implant retention. We did observe one patient who had radiographic loosening of the construct without necessity for treatment.CONCLUSION:The combination of an antiprotrusio cage with tantalum augments is a promising technique in treating large acetabular defects. A major risk of PJI and instability due to large bone and soft tissue defects needs special attention.

AIMS Head-taper corrosion is a cause of failure in total hip arthroplasty (THA). Recent reports have described an increasing number of V40 taper failures with adverse local tissue reaction (ALTR). However, the real incidence of V40 taper damage and its cause remain unknown. The aim of this study was to evaluate the long-term incidence of ALTR in a consecutive series of THAs using a V40 taper and identify potentially related factors. METHODS Between January 2006 and June 2007, a total of 121 patients underwent THA using either an uncemented (Accolade I, made of Ti12Mo6Zr2Fe; Stryker, USA) or a cemented (ABG II, made of cobalt-chrome-molybdenum (CoCrMo); Stryker) femoral component, both with a V40 taper (Stryker). Uncemented acetabular components (Trident; Stryker) with crosslinked polyethylene liners and CoCr femoral heads of 36 mm diameter were used in all patients. At a mean folllow-up of 10.8 years (SD 1.1), 94 patients (79%) were eligible for follow-up (six patients had already undergone a revision, 15 had died, and six were lost to follow-up). A total of 85 THAs in 80 patients (mean age 61 years (24 to 75); 47 (56%) were female) underwent clinical and radiological evaluation, including the measurement of whole blood levels of cobalt and chrome. Metal artifact reduction sequence MRI scans of the hip were performed in 71 patients. RESULTS A total of 20 ALTRs were identified on MRI, with an incidence of 26%. Patients with ALTR had significantly higher median Co levels compared with those without ALTR (2.96 μg/l (interquartile range (IQR) 1.35 to 4.98) vs 1.44 μg/l (IQR 0.79 to 2.5); p = 0.019). Radiological evidence of osteolysis was also significantly associated with ALTR (p = 0.014). Median Cr levels were not significantly higher in those with ALTR compared with those without one (0.97 μg/l (IQR 0.72 to 1.9) v 0.67 μg/l (IQR 0.5 to 1.19; p = 0.080). BMI, sex, age, type of femoral component, head length, the inclination of the acetabular component, and heterotopic ossification formation showed no significant relationship with ALTR. CONCLUSION Due to the high incidence of local ALTR in our cohort after more than ten years postoperatively, we recommend regular follow-up investigation even in asymptomatic patients with V40 taper and metal heads. As cobalt levels correlate with ALTR occurrence, routine metal ion screening and consecutive MRI investigation upon elevation could be discussed. Cite this article: Bone Joint J 2022;104-B(7):852-858.

Dual-mobility cups (DMCs) were introduced in France more than 40 years ago and are increasingly used not only in hip revision but also primary hip arthroplasty. Due to a simulated large-head articulation and increased jumping distance, DMCs can contribute to a high range of motion in the hip joint and reduce the risk of instability. Numerous studies have reported low dislocation rates and high survival rates in the mid-term follow-up. Nevertheless, long-term data, especially on primary hip replacement, remain limited, and the effect of recent designs and material innovations is still unclear. Therefore, primary DMCs are mainly proposed in patients at high risk for dislocation (i.e. pelvitrochanteric insufficiency, compromised spinopelvic mobility, neuromuscular disorders, obesity and femoral neck fractures). Based on a review of recently published studies referring to these indications, the current study discusses the advantages and disadvantages of DMCs.

Abstract Dual-mobility cups (DMCs) were introduced in France more than 40 years ago and are increasingly used not only in hip revision but also primary hip arthroplasty. Due to a simulated large-head articulation and increased jumping distance, DMCs can contribute to a high range of motion in the hip joint and reduce the risk of instability. Numerous studies have reported low dislocation rates and high survival rates in the mid-term follow-up. Nevertheless, long-term data, especially on primary hip replacement, remain limited, and the effect of recent designs and material innovations is still unclear. Therefore, primary DMCs are mainly proposed in patients at high risk for dislocation (i.e. pelvitrochanteric insufficiency, compromised spinopelvic mobility, neuromuscular disorders, obesity and femoral neck fractures). Based on a review of recently published studies referring to these indications, the current study discusses the advantages and disadvantages of DMCs. Zusammenfassung Tripolare Pfannen bzw. Dual-Mobility-Pfannen (dual mobility cups, DMCs) wurden bereits vor über 40 Jahren in Frankreich eingeführt und erfahren nun auch in Deutschland zunehmende Anwendung – nicht nur in der Revisionsendoprothetik, sondern auch in der Primärendoprothetik. Durch das simulierte Großkopfprinzip mit doppelter Artikulation sollen DMCs einen hohen Bewegungsumfang im Hüftgelenk mit reduzierter Luxationsgefahr gewährleisten. Inzwischen zeigen zahlreiche Studien geringe Dislokationsraten sowie hohe Überlebensraten im mittelfristigen Follow-up. Es gibt allerdings noch relativ wenige Langzeitdaten, insbesondere zum Einsatz in der Primärendoprothetik und der Stellenwert von Material- bzw. Designvarianten ist bislang noch unklar. Aus diesem Grund werden DMCs in der Primärendoprothetik aktuell vor allem bei Patient*innen mit erhöhtem Instabilitätsrisiko propagiert. Dazu gehören insbesondere eine Insuffizienz der pelvitrochantären Muskulatur, die eingeschränkte spinopelvine Mobilität, neuromuskuläre Erkrankungen oder Adipositas permagna sowie der Einsatz in der Frakturendoprothetik. Basierend auf einer Literaturübersicht zu diesen Indikationen wird der aktuelle Diskussionsstand zusammengefasst.

ZusammenfassungDer primäre Hüft- und Kniegelenkersatz sind ein sehr häufig durchgeführtes und erfolgreiches Behandlungsverfahren bei fortgeschrittener Arthrose. Für moderne Hüft- und Knietotalendoprothesen wird über sehr gute Langzeitüberlebensraten berichtet. Vor dem Hintergrund steigender Aktivitätsansprüche und der zunehmend häufigeren Behandlung von Patienten mit schwererem Nebenerkrankungsprofil gewinnt die Analyse von patientenbezogenen Einflussfaktoren und Outcome-Kriterien weiterhin an Bedeutung. Mit der Etablierung interdisziplinärer Behandlungskonzepte zur rascheren Genesung und Komplikationsreduktion wird auf diese Entwicklung eingegangen. Bei einer Versorgung in zertifizierten Endoprothetikzentren (EndoCert©) sind standardisierte Behandlungspfade und die Vorhaltung spezialisierter Infrastruktur gewährleistet. In die Ergebnisbewertung gehen neben Routine-Indikatoren der externen Qualitätssicherung mittlerweile auch Daten aus dem Deutschen Endoprothesenregister (EPRD©) ein, das von der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie (DGOOC) etabliert wurde. Dieser Übersichtsbeitrag berichtet über die Versorgungssituation in der Hüft- und Knieendoprothetik bei Arthrose in Deutschland. Es wird auf Indikationsstellung, Prinzipien der Operationsmethodik, Implantatsysteme sowie aktuelle Entwicklungen und Behandlungskonzepte eingegangen.