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Borg, T., Hernefalk, B. & Hailer, N. P. (2019). Acute total hip arthroplasty combined with internal fixation for displaced acetabular fractures in the elderly: A short-term comparison with internal fixation alone after a minimum of two years. The Bone & Joint Journal, 101B(4), 478-483
Open this publication in new window or tab >>Acute total hip arthroplasty combined with internal fixation for displaced acetabular fractures in the elderly: A short-term comparison with internal fixation alone after a minimum of two years
2019 (English)In: The Bone & Joint Journal, ISSN 2049-4394, E-ISSN 2049-4408, Vol. 101B, no 4, p. 478-483Article in journal (Refereed) Published
Abstract [en]

Aims

Displaced, comminuted acetabular fractures in the elderly are increasingly common, but there is no consensus on whether they should be treated non-surgically, surgically with open reduction and internal fixation (ORIF), or with acute total hip arthroplasty (THA). A combination of ORIF and acute THA, an approach called 'combined hip procedure' (CHP), has been advocated and our aim was to compare the outcome after CHP or ORIF alone.

Patients and Methods

A total of 27 patients with similar acetabular fractures (severe acetabular impaction with or without concomitant femoral head injury) with a mean age of 72.2 years (50 to 89) were prospectively followed for a minimum of two years. In all, 14 were treated with ORIF alone and 13 were treated with a CHP. Hip joint and patient survival were estimated. Operating times, blood loss, radiological outcomes, and patient-reported outcomes were assessed.

Results

No patient in the CHP group required further hip surgery, giving THA a survival rate of 100% (95% confidence interval (CI) 100 to 100) after three years, compared with 28.6% hip joint survival in the ORIF group (95% CI 12.5 to 65.4; p = 0.001). No dislocations or deep infections occurred in the CHP group. No patient died within the first year after index surgery, but patient survival was lower in the CHP group after three years. There were no relevant differences in patient-reported outcomes.

Conclusion

The CHP confers a considerably reduced need of further surgery when compared with ORIF alone in elderly patients with complex acetabular fractures. These findings encourage both further use of, and larger prospective studies on, the CHP.

National Category
Orthopaedics
Identifiers
urn:nbn:se:uu:diva-382251 (URN)10.1302/0301-620X.101B4.BJJ-2018-1027.R2 (DOI)000462754300019 ()30929478 (PubMedID)
Available from: 2019-05-03 Created: 2019-05-03 Last updated: 2019-05-03Bibliographically approved
Clewemar, P., Hailer, N. P., Hailer, Y., Klar, J., Kindmark, A., Ljunggren, Ö. & Stattin, E.-L. (2019). Expanding the phenotypic spectrum of osteogenesis imperfecta type V including heterotopic ossification of muscle origins and attachments. Molecular Genetics & Genomic Medicine, 7(7), Article ID e00723.
Open this publication in new window or tab >>Expanding the phenotypic spectrum of osteogenesis imperfecta type V including heterotopic ossification of muscle origins and attachments
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2019 (English)In: Molecular Genetics & Genomic Medicine, ISSN 2324-9269, Vol. 7, no 7, article id e00723Article in journal (Refereed) Published
Abstract [en]

Background

Osteogenesis imperfecta (OI) is a clinical and genetic heterogeneous group of connective tissue disorders, characterized by bone fragility and a propensity to fracture.

Methods

In this report we describe the clinical phenotype of two patients, a 28‐year‐old woman and her mother (54 years old), both with a history of short stature and multiple fractures.

Results

Exome sequencing revealed the recurring IFITM5:c.‐14 C>T variant causing OI type V. Both patients had several fractures during childhood. CT‐scan and scintigraphy showed ossification of the origin and attachment of muscles and hypertrophic callus formation.

Conclusion

Ossification of the origin and attachment of muscles seems to be part of the phenotype in patients with OI type V.

Keywords
BRIL, heterotopic ossification, IFITM5, Osteogenesis imperfecta type V
National Category
Medical Genetics
Identifiers
urn:nbn:se:uu:diva-387239 (URN)10.1002/mgg3.723 (DOI)000475675000062 ()31099171 (PubMedID)
Available from: 2019-06-20 Created: 2019-06-20 Last updated: 2019-08-15Bibliographically approved
Weiss, R. J., Karrholm, J., Rolfson, O. & Hailer, N. P. (2019). Increased early mortality and morbidity after total hip arthroplasty in patients with socioeconomic disadvantage: a report from the Swedish Hip Arthroplasty Register. Acta Orthopaedica, 90(3), 264-269
Open this publication in new window or tab >>Increased early mortality and morbidity after total hip arthroplasty in patients with socioeconomic disadvantage: a report from the Swedish Hip Arthroplasty Register
2019 (English)In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 90, no 3, p. 264-269Article in journal (Refereed) Published
Abstract [en]

Background and purpose

Socioeconomic status is associated with the outcome of major surgery. We investigated the association of socioeconomic status with the risk of early mortality and readmissions after primary total hip arthroplasty (THA).

Patients and methods

We obtained information on income, education, immigration, and cohabiting status as well as comorbidities of 166,076 patients who underwent primary THA due to primary osteoarthritis (OA) from the Swedish Hip Arthroplasty Register, the Swedish National Inpatient Register and Statistics Sweden. Multivariable Cox regression models were fitted to estimate the adjusted risk of mortality or readmissions within 90 days after index surgery.

Results

Compared with patients on a low income, the adjusted risk of 30-day mortality was considerably lower in patients on a high income (hazard ratio [HR] 0.5, 95% confidence interval [CI] 0.3-0.7) and in those on a medium income (HR 0.7, CI 0.6-0.9). Similar risk reductions were found for the endpoint 90-day mortality. Patients with a high income had a lower adjusted risk of readmission for cardiovascular reasons than those with a low income (HR 0.7, CI 0.6-0.9), as had those with a higher level of education (adjusted HR 0.7, CI 0.6-0.9). Patients with higher socioeconomic status had a lower degree of comorbidities than socioeconomically disadvantaged patients. However, adjusting for socioeconomic confounders in multivariable models only marginally influenced the predictive ability of the models, as expressed by their area under the curve.

Interpretation

Income and level of education are strongly associated with early mortality and readmissions after primary THA, and both parameters are closely connected to health status. Since adjustment for socioeconomic confounders only marginally improved the predictive ability of multivariable regression models our findings indicate that comorbidities may under certain circumstances serve as an acceptable proxy measure of socioeconomic background.

National Category
Orthopaedics
Identifiers
urn:nbn:se:uu:diva-387596 (URN)10.1080/17453674.2019.1598710 (DOI)000469038600014 ()30931670 (PubMedID)
Available from: 2019-06-26 Created: 2019-06-26 Last updated: 2019-06-26Bibliographically approved
Hailer, N. (2018). 20 years of porous tantalum in primary and revision hip arthroplasty-time for a critical appraisal. Acta Orthopaedica, 89(3), 254-255
Open this publication in new window or tab >>20 years of porous tantalum in primary and revision hip arthroplasty-time for a critical appraisal
2018 (English)In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 89, no 3, p. 254-255Article in journal, Editorial material (Other academic) Published
National Category
Surgery
Identifiers
urn:nbn:se:uu:diva-357662 (URN)10.1080/17453674.2018.1463007 (DOI)000431519600002 ()29726759 (PubMedID)
Available from: 2018-08-23 Created: 2018-08-23 Last updated: 2018-08-23Bibliographically approved
Rysinska, A., Skoldenberg, O., Garland, A., Rolfson, O., Aspberg, S., Eisler, T., . . . Gordon, M. (2018). Aseptic loosening after total hip arthroplasty and the risk of cardiovascular disease: A nested case-control study. PLoS ONE, 13(11), Article ID e0204391.
Open this publication in new window or tab >>Aseptic loosening after total hip arthroplasty and the risk of cardiovascular disease: A nested case-control study
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2018 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 13, no 11, article id e0204391Article in journal (Refereed) Published
Abstract [en]

Background: Patients with surgically treated osteoarthritis of the hip have an increased risk of cardiovascular morbidity and mortality many years after the operation compared with controls. Our hypothesis is that this increased risk after total hip arthroplasty (THA) is mediated by development of periprosthetic osteolysis leading to aseptic loosening of the implant.

Methods: We conducted a nation-wide, nested, case-control study consisting of patients receiving a cemented THA due to osteoarthritis between the years 1992 and 2005. Our study population included a total of 14,430 subjects identified in the Swedish hip arthroplasty register and linked to the Swedish National Patient Register. The case group consisted of patients (n = 2,886) who underwent reoperation of the treated hip due to osteolysis or aseptic loosening at any time within five years after the index surgery. Each case was matched with four controls (n = 11,544) who had not undergone reoperation. The main outcomes were cardiovascular events i.e. myocardial infarction, heart failure and cerebral infarction according to ICD-codes and time to the first cardiovascular event during the exposure period. Outcomes were subgrouped into cardiac and cerebral events. We used regression models to calculate the incidence rates and adjusted our results for confounders.

Findings: Overall, 5.1% of patients had cardiac events, with slightly more overall cardiovascular events occurring in the control group (8.1% vs. 6.7%, odds ratio 0.8, 95% confidence interval (CI) 0.7 to 1.0). After adjusting for confounders, the case group had an increased relative risk of 1.3 (95% confidence interval (CI) 1.1 to 1.3) for total number of cardiovascular events. Similar effect sizes were observed for time to first event.

Interpretation: Patients with osteoarthritis who received THA and subsequently underwent a revision operation due to loosening had a higher relative risk of developing cardiovascular events than controls. Thus there is an association which could be explained by a common inflammatory disease pathway that requires further experimental research.

National Category
Orthopaedics
Identifiers
urn:nbn:se:uu:diva-371537 (URN)10.1371/journal.pone.0204391 (DOI)000450138500010 ()30427844 (PubMedID)
Funder
Åke Wiberg Foundation
Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-01-07Bibliographically approved
Brüggemann, A., Mallmin, H. & Hailer, N. P. (2018). Do dual-mobility cups cemented into porous tantalum shells reduce the risk of dislocation after revision surgery?: A retrospective cohort study on 184 patients. Acta Orthopaedica, 89(2), 156-162
Open this publication in new window or tab >>Do dual-mobility cups cemented into porous tantalum shells reduce the risk of dislocation after revision surgery?: A retrospective cohort study on 184 patients
2018 (English)In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 89, no 2, p. 156-162Article in journal (Refereed) Published
Abstract [en]

Background and purpose Dual-mobility cups (DMCs) reduce the risk of dislocation and porous tantalum (TM) shells show favorable osseointegration after acetabular revision surgery, yet the combination of these implants has not been studied. We hypothesized that (1) cementing a DMC into a TM shell decreases the risk of dislocation; (2) DMCs cemented into TM shells are not at greater risk of re-revision; (3) liberation of tantalum ions is marginal after use of this combined technique.Patients and methods We investigated the outcome in 184 hips (184 patients) after acetabular revision surgery with TM shells, fitted either with DMCs (n = 69), or with standard polyethylene (PE) liners (n = 115). Chart follow-up was complete for all patients, and the occurrence of dislocations and re-revisions was recorded. 20 were deceased, 50 were unable to attend follow-up, leaving 114 for assessment of hip function after 4.9 (0.5-8.9) years, radiographs were obtained in 99, and tantalum concentrations in 84 patients.Results 1 patient with a DMC had a dislocation, whereas 14 patients with PE liners experienced at least 1 dislocation. 11 of 15 re-revisions in the PE group were necessitated by dislocations, whereas none of the 2 re-revisions in the DMC group was performed for this reason. Hence, dislocation-free survival after 4 years was 99% (95% CI 96-100) in the DMC group, whereas it was 88% (CI 82-94, p = 0.01) in the PE group. We found no radiographic signs of implant failure in any patient. Mean tantalum concentrations were 0.1 mu l/L (CI 0.05-0.2) in the DMC group and 0.1 mu g/L (CI 0.05-0.2) in the PE group.Interpretation Cementing DMCs into TM shells reduces the risk of dislocation after acetabular revision surgery without jeopardizing overall cup survival, and without enhancing tantalum release.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2018
National Category
Orthopaedics
Identifiers
urn:nbn:se:uu:diva-353002 (URN)10.1080/17453674.2018.1432927 (DOI)000429335700004 ()29400106 (PubMedID)
Available from: 2018-07-13 Created: 2018-07-13 Last updated: 2018-07-13Bibliographically approved
Eriksson, H. K., Nordström, J., Gabrysch, K., Hailer, N. P. & Lazarinis, S. (2018). Does the Alpha-defensin Immunoassay or the Lateral Flow Test Have Better Diagnostic Value for Periprosthetic Joint Infection?: A Systematic Review. Clinical Orthopaedics and Related Research, 476(5), 1065-1072
Open this publication in new window or tab >>Does the Alpha-defensin Immunoassay or the Lateral Flow Test Have Better Diagnostic Value for Periprosthetic Joint Infection?: A Systematic Review
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2018 (English)In: Clinical Orthopaedics and Related Research, ISSN 0009-921X, E-ISSN 1528-1132, Vol. 476, no 5, p. 1065-1072Article, review/survey (Refereed) Published
Abstract [en]

Background: Measuring alpha-defensin concentrations in synovial fluid may help to diagnose periprosthetic joint infection (PJI). There are two commercially available methods for measuring alpha-defensin in synovial fluid: the enzyme-linked immunosorbent assay-based Synovasure (R) alpha-defensin immunoassay, which gives a numeric readout within 24 hours, and the Synovasure lateral flow test, which gives a binary readout within 20 minutes. There is no compilation of the existing literature to support the use of one of these two tests over the other.

Questions/purposes: Does the immunoassay or the lateral flow test have better diagnostic value (sensitivity and specificity) in diagnosing PJI?

Methods: We followed PRISMA guidelines and identified all studies on alpha-defensin concentration in synovial fluid as a PJI diagnostic marker, indexed to April 14, 2017, in PubMed, JSTOR, Google Scholar, and OVID databases. The search retrieved 1578 records. All prospective and retrospective studies on alpha-defensin as a PJI marker (PJI classified according to the criteria of the Musculoskeletal Infection Society) after THA or TKA were included in the analysis. All studies used only one of the two commercially available test methods, but none of them was comparative. After excluding studies with overlapping patient populations, four studies investigating the alpha-defensin immunoassay and three investigating the lateral flow test remained. Alpha-defensin immunoassay studies included 482 joints and lateral flow test studies included 119. The quality of the trials was assessed according to the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. The heterogeneity among studies was evaluated by the I-2 index, indicating that the heterogeneity of the included studies was low. Pooled sensitivity, specificity, positive and negative likelihood ratios, and receiver operating curves were calculated for each method and compared with each other.

Results: The alpha-defensin immunoassay had superior overall diagnostic value compared with the lateral flow test (area under the curve, 0.98 versus 0.75) with higher sensitivity (96% [90%-98%] versus 71% [55%-83%], p < 0.001), but no difference in specificity with the numbers available (96% [93%-97%] versus 90% [81%-95%], p = 0.060).

Conclusions: Measurement of alpha-defensin in synovial fluid is a valuable complement to existing diagnostic criteria, and the immunoassay test detects PJI more accurately than the lateral flow test. The lateral flow test has lower sensitivity, making it difficult to rule out infection, but its relatively high specificity combined with the advantage of a quick response time can make it useful to rule in infection perioperatively.

Level of Evidence: Level III, diagnostic study.

National Category
Orthopaedics
Identifiers
urn:nbn:se:uu:diva-357653 (URN)10.1007/s11999.0000000000000244 (DOI)000431411000027 ()29601381 (PubMedID)
Note

Correction in: Clinical Orthopaedics and Related Research, 2018, vol. 476, issue 7, page 1545

DOI: 10.1097/CORR.0000000000000362

Available from: 2018-08-28 Created: 2018-08-28 Last updated: 2018-11-27Bibliographically approved
Hailer, Y. & Hailer, N. P. (2018). Is Legg-Calve-Perthes Disease a Local Manifestation of a Systemic Condition?. Clinical Orthopaedics and Related Research, 476(5), 1055-1064
Open this publication in new window or tab >>Is Legg-Calve-Perthes Disease a Local Manifestation of a Systemic Condition?
2018 (English)In: Clinical Orthopaedics and Related Research, ISSN 0009-921X, E-ISSN 1528-1132, Vol. 476, no 5, p. 1055-1064Article in journal (Refereed) Published
Abstract [en]

Background: Osteochondrosis includes numerous diseases that occur during rapid growth, characterized by disturbances of endochondral ossification. One example, Legg-Calvé-Perthes disease, is characterized by disruption of the blood supply to the femoral head epiphysis, and a systemic etiology often has been suggested. If this were the case, secondary osteochondroses at locations other than the hip might be expected to be more common among patients with Legg-Calvé-Perthes disease, but to our knowledge, this has not been evaluated in a nationwide sample.

Questions/purposes: (1) Do patients with Legg-Calvé-Perthes disease have an increased prevalence of secondary osteochondroses at locations other than the hip? (2) Is the concept of Legg-Calvé-Perthes disease a systemic etiology supported by a higher prevalence of the metabolic diseases obesity and hypothyroidism?

Methods: We designed a retrospective population-based cohort study with data derived from the Swedish Patient Registry (SPR). The SPR was established in 1964 and collects information on dates of hospital admission and discharge, registered diagnoses (categorized along the International Classification of Diseases [ICD]), and applied treatments during the entire lifetime of all Swedish citizens with high validity. Analyzing the time span from 1964 to 2011, we identified 3183 patients with an ICD code indicative of Legg-Calvé-Perthes disease and additionally sampled 10 control individuals per patient with Legg-Calvé-Perthes disease, matching for sex, age, and residence, resulting in 31,817 control individuals. The prevalence of secondary osteochondroses, obesity, and hypothyroidism was calculated separately for patients with Legg-Calvé-Perthes disease and control individuals based on the presence of ICD codes indicative of these conditions. Using logistic regression analysis, we compared the adjusted relative risk of having either of these conditions develop between patients with Legg-Calvé-Perthes disease and their matched control subjects. The mean followup was 26.1 years (range, 2.8-65 years).

Results: The prevalence of secondary osteochondroses was greater among patients with Legg-Calvé-Perthes disease (3.11%) than among control subjects (0.31%), resulting in an increased adjusted risk of an association with such lesions in the patients (relative risk [RR], 10.3; 95% confidence interval [CI], 7.7-13.6; p < 0.001). When stratified by sex, we attained a similarly increased risk ratio for females (RR, 12.5; 95% CI, 6.1-25.8; p < 0.001) as for males (RR, 9.9; 95% CI, 7.3-13.5; p < 0.001). Patients with Legg-Calvé-Perthes disease had an increased adjusted risk of an association with obesity (RR, 2.8; 95% CI, 1.9-4.0; p < 0.001) or hypothyroidism (RR, 2.6; 95% CI, 1.7-3.8; p < 0.001) when compared with control subjects.

Conclusions: To our knowledge, this is the first population-based description of a robust association of Legg-Calvé-Perthes disease with osteochondroses at locations other than the hip, and we also found increased risk estimates for an association with obesity and hypothyroidism in patients with Legg-Calvé-Perthes disease. Our findings strengthen the hypothesis that Legg-Calvé-Perthes disease is the local manifestation of a systemic disease, indicative of an underlying common disease pathway that requires further investigation. Physicians should be aware that patients with Legg-Calvé-Perthes disease may present with secondary osteochondroses and metabolic comorbidities.

National Category
Orthopaedics
Identifiers
urn:nbn:se:uu:diva-356074 (URN)10.1007/s11999.0000000000000214 (DOI)000431411000026 ()29481348 (PubMedID)
Available from: 2018-07-13 Created: 2018-07-13 Last updated: 2018-07-13Bibliographically approved
Schizas, N., König, N., Andersson, B., Vasylovska, S., Hoeber, J., Kozlova, E. & Hailer, N. (2018). Neural crest stem cells protect spinal cord neurons from excitotoxic damage and inhibit glial activation by secretion of brain-derived neurotrophic factor. Cell and Tissue Research, 372(3), 493-505
Open this publication in new window or tab >>Neural crest stem cells protect spinal cord neurons from excitotoxic damage and inhibit glial activation by secretion of brain-derived neurotrophic factor
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2018 (English)In: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, Vol. 372, no 3, p. 493-505Article in journal (Refereed) Published
Abstract [en]

The acute phase of spinal cord injury is characterized by excitotoxic and inflammatory events that mediate extensive neuronal loss in the gray matter. Neural crest stem cells (NCSCs) can exert neuroprotective and anti-inflammatory effects that may be mediated by soluble factors. We therefore hypothesize that transplantation of NCSCs to acutely injured spinal cord slice cultures (SCSCs) can prevent neuronal loss after excitotoxic injury. NCSCs were applied onto SCSCs previously subjected to N-methyl-d-aspartate (NMDA)-induced injury. Immunohistochemistry and TUNEL staining were used to quantitatively study cell populations and apoptosis. Concentrations of neurotrophic factors were measured by ELISA. Migration and differentiation properties of NCSCs on SCSCs, laminin, or hyaluronic acid hydrogel were separately studied. NCSCs counteracted the loss of NeuN-positive neurons that was otherwise observed after NMDA-induced excitotoxicity, partly by inhibiting neuronal apoptosis. They also reduced activation of both microglial cells and astrocytes. The concentration of brain-derived neurotrophic factor (BDNF) was increased in supernatants from SCSCs cultured with NCSCs compared to SCSCs alone and BDNF alone mimicked the effects of NCSC application on SCSCs. NCSCs migrated superficially across the surface of SCSCs and showed no signs of neuronal or glial differentiation but preserved their expression of SOX2 and Krox20. In conclusion, NCSCs exert neuroprotective, anti-apoptotic and glia-inhibitory effects on excitotoxically injured spinal cord tissue, some of these effects mediated by secretion of BDNF. However, the investigated NCSCs seem not to undergo neuronal or glial differentiation in the short term since markers indicative of an undifferentiated state were expressed during the entire observation period.

Keywords
Neuroprotection, Suppressed glial activation, Excitotoxicity, Apoptosis, Secretion of soluble factors
National Category
Cell Biology
Identifiers
urn:nbn:se:uu:diva-356852 (URN)10.1007/s00441-018-2808-z (DOI)000432109000004 ()29516218 (PubMedID)
Funder
Swedish Research Council, 20716Stiftelsen Olle Engkvist Byggmästare
Available from: 2018-08-16 Created: 2018-08-16 Last updated: 2018-08-16Bibliographically approved
Tsikandylakis, G., Kärrholm, J., Hailer, N. P., Eskelinen, A., Mäkelä, K. T., Hallan, G., . . . Mohaddes, M. (2018). No Increase in Survival for 36-mm versus 32-mm Femoral Heads in Metal-on-polyethylene THA: A Registry Study. Clinical Orthopaedics and Related Research, 476(12), 2367-2378
Open this publication in new window or tab >>No Increase in Survival for 36-mm versus 32-mm Femoral Heads in Metal-on-polyethylene THA: A Registry Study
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2018 (English)In: Clinical Orthopaedics and Related Research, ISSN 0009-921X, E-ISSN 1528-1132, Vol. 476, no 12, p. 2367-2378Article in journal (Refereed) Published
Abstract [en]

Background During the past decade, the 32-mm head has replaced the 28-mm head as the most common head size used in primary THA in many national registries, and the use of 36-mm heads has also increased. However, it is unclear whether 32-mm and 36-mm heads decrease the revision risk in metal-on-polyethylene (MoP) THA compared with 28-mm heads.

Questions/purposes (1) In the setting of the Nordic Arthroplasty Register Association database, does the revision risk for any reason differ among 28-, 32-, and 36-mm head sizes in patients undergoing surgery with MoP THA? (2) Does the revision risk resulting from dislocation decrease with increasing head diameter (28-36 mm) in patients undergoing surgery with MoP THA in the same registry?

Methods Data were derived from the Nordic Arthroplasty Register Association database, a collaboration among the national arthroplasty registries of Denmark, Finland, Norway, and Sweden. Patients with primary osteoarthritis who had undergone primary THA with a 28-, 32-, or 36-mm MoP bearing from 2003 to 2014 were included. Patients operated on with dual-mobility cups were excluded. In patients with bilateral THA, only the first operated hip was included. After applying the inclusion criteria, the number of patients and THAs with a complete data set was determined to be 186,231, which accounted for 51% of all hips (366,309) with primary osteoarthritis operated on with THA of any head size and bearing type during the study observation time. Of the included patients, 60% (111,046 of 186,231) were women, the mean age at surgery was 70 (± 10) years, and the median followup was 4.5 years (range, 0-14 years). A total of 101,094 patients had received a 28-mm, 57,853 a 32-mm, and 27,284 a 36-mm head with 32 mm used as the reference group. The revision of any component for any reason was the primary outcome and revision for dislocation was the secondary outcome. Very few patients are estimated to be lost to followup because emigration in the population of interest (older than 65-70 years) is rare. A Kaplan-Meier analysis was used to estimate THA survival for each group, whereas Cox regression models were fitted to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for THA revision comparing the 28- and 36-mm head diameters with the 32-mm head diameters adjusting for age, sex, year of surgery, type of cup and stem fixation, polyethylene type (crosslinked versus conventional), and surgical approach.

Results In the adjusted Cox regression model, there was no difference in the adjusted risk for revision for any reason between patients with 28-mm (HR, 1.06; 95% CI, 0.97–0.16) and 32-mm heads, whereas the risk of revision was higher for patients with 36-mm heads (HR, 1.14; 95% CI, 1.04–1.26) compared with patients with 32-mm heads. Patients with 28-mm heads had a higher risk of revision for dislocation (HR, 1.67; 95% CI, 1.38–1.98) compared with 32 mm, whereas there was no difference between patients with 36-mm (HR, 0.85; 95% CI, 0.70–1.02) and 32-mm heads.

Conclusions After adjusting for relevant confounding variables, we found no benefits for 32-mm heads against 28 mm in terms of overall revision risk. However, when dislocation risk is considered, 32-mm heads would be a better option, because they had a lower risk of revision resulting from dislocation. There were no benefits with the use of 36-mm heads over 32 mm, because the transition from 32 to 36 mm was associated with a higher risk of revision for all reasons, which was not accompanied by a decrease in the risk of revision resulting from dislocation. The use of 32-mm heads appears to offer the best compromise between joint stability and other reasons for revision in MoP THA. Further studies with longer followup, especially of 36-mm heads, as well as better balance of confounders across head sizes and better control of patient-related risk factors for THA revision are needed.

Level of Evidence Level III, therapeutic study.

Place, publisher, year, edition, pages
LIPPINCOTT WILLIAMS & WILKINS, 2018
National Category
Orthopaedics
Identifiers
urn:nbn:se:uu:diva-377719 (URN)10.1097/CORR.0000000000000508 (DOI)000457619900015 ()30260863 (PubMedID)
Available from: 2019-03-08 Created: 2019-03-08 Last updated: 2019-03-08Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3233-2638

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