Bilaterale umschriebene Osteolyse nach zementierter H�fttotalendoprothesenimplantation

Favorable revision-free survivorship of cemented arthroplasty following failed proximal femoral nail antirotation: a case series with a median follow-up of 10 years

BACKGROUND

Given the ever-increasing rate of failure related to proximal femoral nail antirotation (PFNA), it is expected that an increasing number of PFNA individuals will undergo conversion to total hip arthroplasty (THA). The long-term survivorship of conversion of the initial PFNA to cemented THA is still debated. The aim of this retrospective study was to assess the long-term revision-free survivorship of cemented THAs after initial failures of PFNA in geriatric individuals.

METHODS

Consecutive geriatric individuals who underwent secondary cemented THA after initial PFNA fixation from July 2005 to July 2018, were retrospectively identified from three medical centres. The primary outcome was revision-free survivorship estimated using the Kaplan-Meier method and Cox proportional hazards regression with revision for any reason as the endpoint; secondary outcomes were functional outcomes and key THA-related complications. Follow-ups occurred at 3 months, 6 months, 12 months and then every 12 months after conversion.

RESULTS

In total, 186 consecutive patients (186 hips) were available for study inclusion. The median follow-up was 120.7 months (60-180 months) in the cohort. Kaplan-Meier survivorship with revision for any reason as the end point showed that the 10-year revision-free survival rate was 0.852 (95% confidence interval [CI], 0.771-0.890). Good functional outcomes were seen, and the HHS decreased markedly over the 24th month to the final follow-up interval from 92.2 to 75.1 (each p < 0.05). The overall rate of key THA-related complications was 16.1% (30/186).

CONCLUSION

Cemented THA executed following initial PFNA failure may yield satisfactory revision-free survival and, at least for the initial 10 years after conversion, good functional outcomes and a 16.1% complication rate of key THA-related complications, which supports the trend towards increased use of cemented THA.

[Orthopedic surgical implants and allergies. Joint statement by the Implant Allergy Working Group (AK 20) of the DGOOC (German Association of Orthopedics and Orthopedic Surgery), DKG (German Contact Dermatitis Research Group) and DGAKI (German Society for Allergology and Clinical Immunology)]

Materials used in osteosynthesis or artificial joint replacement are usually well tolerated. Complaints after such operations are mostly related to infection or mechanical problems but may also be caused by allergic reactions. The latter encompass skin changes, e.g., eczema, delayed wound/bone healing, recurrent effusion, pain, or implant loosening. In contrast to the high incidence of cutaneous metal contact allergy, allergies associated with implants are a rare condition. However, epidemiological data on the incidence of implant-related allergic reactions are still missing. Typical elicitors are nickel, chromium, cobalt, and constituents of bone cement (acrylates und additives such as gentamicin or benzoyl peroxide). After exclusion of the most common differential diagnoses, allergy diagnostic procedures are primarily based on patch tests including a metal and bone cement component series. Additional analysis of periimplant tissue is recommended. However, further studies are necessary to show the significance of the histologic findings and the role of the lymphocyte transformation test (LTT). Which combinations of factors will induce allergic sensitization to implants or trigger periimplant allergic reactions in the case of preexisting cutaneous metal allergy is still unknown. Titanium-based osteosynthesis materials are recommended for metal allergic patients. In elective hip replacements, a ceramic/polyethylene (PE) articulation should be used, and in knee replacements "alternative materials". If a regular, potentially applicable CoCr/PE articulation is preferred, the patient must be well informed and must give his/her written consent.

Das Allergiepotenzial von Implantatwerkstoffen auf Titanbasis

AIM

The aim of this investigation is to evaluate the allergic potential of titanium and titanium alloys for surgical implant applications.

MATERIALS AND METHODS

Discs cut from rods supplied by five different titanium suppliers in several diameters were investigated. The samples were cp-Titanium as well as Ti6Al4 V and Ti6Al7Nb, 6 mm thick with a diameter of between 6 and 60 mm. The material was checked by optical spectral analysis.

RESULTS

In all samples except iodidtitanium, a Nickel content of 0.012-0,034 wt% could be detected.

CONCLUSION

The low nickel content in the implant material results from the production process. The nickel atoms are in solid solution in the titanium lattice. Nickel allergic patients may develop hypersensitivity reactions even due to this low nickel content. Hence, this reaction may be falsely attributed to the titanium material itself. Measurements of ion concentration in the body are helpful for quantifying the maximum content of nickel in titanium materials for surgical implant applications. In addition, technical questions related to the production of nickel free titanium materials for allergic patients have to be solved.