Aim

Previous publications have suggested that the incidence of revisions due to infection after THA is increasing. We performed updated time-trend analyses of risk and timing of revision due to infection after primary THAs in the Nordic countries during the period 2004–2018.

Young patients are at increased risk of revision after primary THA (THA). The bearing surface may be of importance for the longevity of the joint.

We aimed to compare the risk of revision of primary stemmed cementless THA with MoM and CoC with metal-on-highly-crosslinked-polyethylene (MoXLP) bearings in patients between 20–54 years.

From NARA, we included 2,153 MoM, 4,120 CoC and 10,329 MoXLP THA operated between 1995 and 2017. Kaplan-Meier estimator was used for calculation of THA survivorship and Cox regression to estimate the hazard ratio (HR) of revision (95% CI) due to any and specific causes. MoXLP was reference.

The median follow-up was 10.3 years for MoM, 6.6 years for CoC and 4.8 years for MoXLP. 15 years postoperatively the Kaplan-Meier survival estimates were 80% (78–83%) for MoM, 92% (91–93%) for CoC and 94% (93–95%) for MoXLP. The 0–2, 2–7 and 7–15 years adjusted HRs of revision by any cause were 1.4 (0.9–2.4), 3.2 (2.1–5.1) and 3.9 (1.9–7.9) for MoM and 1.1 (0.8–1.4), 1.0 (0.7–1.3) and 2.5 (1.3–4.8) for CoC bearings. After 7–15 years follow-up, the unadjusted HR of revision due to aseptic loosening was 5.4 (1.2–24) for MoM and 4.2 (0.9–20) for CoC THA. MoM and CoC had a 7–15 year adjusted HR of revision due to ‘other’ causes of 4.8 (1.6–14) and 2.1 (0.8–5.8).

MoXLP bearings were associated with better survival than MoM and CoC bearings, mainly because of lower risk of revision due to aseptic loosening and ‘other’ causes.

Objective: Hospital volume is a known indicator for orthopaedic adverse events in patients undergoing total hip replacement. The aim of the current study was to evaluate the effect of hospital volume on the length of stay, re-admissions and complications of THR on a population-based level in Finland.

Methods: Using the information from the Hospital Discharge Registry and that of four other National databases, 28,218 THRs performed for primary osteoarthritis were identified for the period covering 1998 to 2005. Hospitals were classified into four groups according to the number of primary and revision hip and knee replacements performed on an annual basis over the whole study period: 1–100 (Group 1), 101–300 (Group 2), 301–600 (Group 3) and 601 or over (Group 4). Logistic regression analysis and generalized linear models were used to study the effect of hospital volume on the length of stay, unscheduled re-admissions, re-operations, dislocations and infections.

Results: The lengths of both the surgical treatment period and the uninterrupted institutional care were shorter for the very high volume hospitals (Group 4) than for the low volume hospitals (Group 1) (p< 0.0001). The odds ratio for dislocations (0.71, 95% CI 0.56–0.91) was significantly lower in the high volume hospitals (Group 3), than in the low volume hospitals (Group 1, the reference group).

Conclusion: Specialization of hip replacements by high volume hospitals should reduce costs by significantly shortening length of stay, and may reduce the dislocation rate.

Background: According to the mid-term results obtained from the previous registry-based studies, survival of cementless stems for aseptic loosening in younger patients with primary osteoarthritis has been better than the survival of cemented stems. However, it has not been clear if the endurance against aseptic loosening of cementless cups is comparable to that of cemented cups. The aim of the present study was to analyze population-based long-term survival rates of the cemented and cementless total hip replacements in patients under the age of fifty-five years with primary osteoarthritis in Finland.

Patients and Methods: Between 1980 and 2006, a total of 7310 primary total hip replacements performed for primary osteoarthritis in patients under the age of fifty-five years were entered in the Finnish Arthroplasty Registry. 4,032 of them fulfilled our inclusion criteria and were subjected to analysis. The implants included were classified in one of the three following groups: implants with a cementless, straight, proximally circumferentially porous-coated stem and a porous-coated press-fit cup (cementless group #1); implants with a cementless, anatomic, proximally circumferentially porous-coated and/ or hydroxyapatite-coated stem with a porous-coated and/or hydroxyapatite-coated press-fit cup (cementless group #2); and a cemented stem combined with a cemented all-polyethylene cup (the cemented group).

Results: Cementless total hip replacements, as well as cementless stems and cups analyzed separately, had a significantly reduced risk of revision for aseptic loosening compared with cemented hip replacements. The 15-year survivorship of cementless stem groups for aseptic loosening was higher than that of cemented stems (89% and 90% vs. 72%). The 15-year survivorship of cementless press-fit porous-coated cups for aseptic loosening was higher than that of cemented cups (80% vs. 71%). When revision for any reason was the end point in survival analyses, however, there were no significant differences among the groups.

Conclusions: Both cementless stems and cementless cups have better resistance to aseptic loosening than cemented implants in long term follow-up in younger patients. Even if liner-exchange revisions are taken into account, the long-term survival of cementless total hip replacements is comparable to that of cemented implants.