Results of ReCap-M2a-Magnum Metal-on-Metal Total Hip Arthroplasty

Metal-on-polyethylene (MoP) bearing surfaces were standardized by Sir John Charnley and are still considered the gold standard in total hip arthroplasty (THA). Nevertheless, MoP THAs caused polyethylene wear and led to osteolysis and revisions, especially among young and active patients. Metal-on-metal (MoM) bearing surfaces were developed to solve these problems. After a brief triumph, however, poorer outcomes raised concerns over MoM THAs as well. A unique type of complication was encountered: adverse reaction to metal debris (ARMD). ARMD has been the reason for excessive failures, in MoM THA. This thesis concentrates on ReCap-M2a-Magnum MoM THA. It has comparably low revision rate of less than 10% at ten years (Australian Orthopaedic Association National Joint Replacement Registry, 2018). The aim of this thesis was to ascertain the frequency and risk factors of ARMD, assess the challenges in revision surgery, and clarify the role of whole blood cobalt and chromium metal ion levels in relation to the ReCap-M2a-Magnum device. Data was obtained from the Turku University Hospital and Oulu University Hospital electronic databases. This was the most common hip device used at Turku University Hospital from 2004 to 2012. We found a high prevalence of ARMD in a systematic screening of all of the ReCap-M2a-Magnum THA patients. Out of 1329 hips, 157 (11.8%) were considered to have definitive ARMD. In revision surgery the femoral head was frequently jammed into the stem, in 29% (20/70) of operations. Head removal was complicated, increasing operation times and intraoperative bleeding. Metal ion measurements are taken frequently during follow-up of MoM THA patients, but no increase was found in unilateral ReCap-M2a-Magnum patients over a mean 2-year interval.Sir John Charnley kehitti sementtikiinnitteisen lonkan tekonivelen, missä komponenttien liukuparina oli metalli-polyetyleeni. Tähän liukupariin on todettu liittyvän polyetyleenihiukkasten irtoamista, minkä on todettu aiheuttavan tekonivelen viereisen luun osteolyysiä. Tästä syystä myös muita liukupareja on tutkittu. Metalli-metalli-liukuparin arveltiin ratkaisevan tämän ongelman. Tästä syystä 2000-luvun alussa ko. liukuparia alettiin käyttää runsaasti lonkan tekonivelleikkauksissa. Varsin pian kuitenkin havaittiin, että tähänkin liukupariin liittyy ongelmia, narinaa, ääntelyä ja ns. metallihierreoireyhtymä (Adverse Reaction to Metal Debris = ARMD). Eri metalli-metalli-liukuparitekoniveliin liittyvät ongelmat vaihtelevat. Tässä väitöskirjassa on tutkittu ReCap-M2a-Magnum -nimisen lonkan metalli-metalli liukupari-mallia. Tähän tekonivelmalliin liittyy muita vastaavia tekonivelmalleja pienempi uusintaleikkausriski. Australian tekonivelrekisterin mukaan tämä riski on alle 10% kymmenessä vuodessa. Osatyössä 1 selvitettiin ReCap-M2a-Magnum tekonivelen nupin ja reisikomponentin kylmähitsautumisen yleisyyttä ja siitä aiheutuvia ongelmia uusintaleikkauksessa. Osatyössä 2 tutkittiin metallihierreoireyhtymän esiintyvyyttä ja sen riskitekijöitä. Osatyössä 3 tutkittiin potilaiden veren koboltti- ja kromipitoisuuksien muutoksia ko. tekonivelleikkauksen jälkeen. Osatöiden potilasaineisto on kerätty Turun yliopistollisen keskussairaalan ja Oulun yliopistollisen sairaalan tekonivelrekistereistä vuosilta 2004-2012. Tutkimusten tuloksena kylmähitsautumisilmiö ReCap-M2a-Magnum tekonivelen nupin ja reisikomponentin kartioliitoksen välissä havaittiin 29 %:ssa uusintaleikkauksia. Tämä ilmiö lisäsi leikkausaikaa ja leikkauksen aikaista veren vuotoa. Tätä tekoniveltä käyttävillä potilailla on lisääntynyt riski saada metallihierreoireyhtymä. Se todettiin 11,8 %:lla tätä tekoniveltä käyttävillä tekonivelpotilailla. Kahden vuoden seuranta-aikana koboltti- ja kromipitoisuudet eivät nouse merkittävästi ReCap-M2a-Magnum lonkan tekoniveltä käyttävillä potilailla

Regional variations in lumbar spine surgery in Finland

Introduction: The regional variation in spine surgery rates has been shown to be large both within and between countries. This variation has been reported to be less in studies from countries with spine registers. The aim of this study was to describe the regional variation in lumbar spine surgery in Finland. Materials and methods: This is a retrospective register study. Data from the Finnish National Hospital Discharge Register (NHDR) were used to calculate and compare the rates of lumbar disc herniation (LDH), decompression, and fusion surgeries in five University Hospital catchment areas, covering the whole Finnish population, from January 1, 1997, through December 31, 2018. Results: A total of 138,119 lumbar spine operations (including LDH, decompression, and fusion surgery) were performed in Finland between 1997 and 2018. The regional differences in the rate of LDH surgery were over fourfold (18 vs. 85 per 100,000 person years), lumbar decompression surgery over threefold (41 vs. 129 per 100,000 person years), and lumbar fusion surgery over twofold (14 vs. 34 per 100,000 person years) in 2018. The mean age of the patients increased in all regions during the study period. Conclusions: In Finland, the regional variations in spine surgeries were vast. In a country with a publicly funded healthcare system, this finding was surprising. The recently created national spine register may serve to shed more light on the reasons for this regional variation.publishedVersionPeer reviewe

Isthmic Spondylolisthesis is Associated with Less Revisions for Adjacent Segment Disease After Lumbar Spine Fusion Than Degenerative Spinal Conditions : A 10-Year Follow-Up Study

Study Design. Prospective, follow-up study. Objective. We aim to compare the rate of revisions for ASD after LSF surgery between patients with IS and DLSD. Summary of Background Data. ASD is a major reason for late reoperations after LSF surgery. Several risk factors are linked to the progression of ASD, but the understanding of the underlying mechanisms is imperfect. If IS infrequently becomes complicated with ASD, it would emphasize the role of the ongoing degenerative process in spine in the development of ASD. Methods. 365 consecutive patients that underwent elective LSF surgery were followed up for an average of 9.7years. Surgical indications were classified into 1) IS (n=64), 2) DLSD (spinal stenosis with or without spondylolisthesis) (n=222), and 3) other reasons (deformities, postoperative conditions after decompression surgery, posttraumatic conditions) (n=79). All spinal reoperations were collected from hospital records. Rates of revisions for ASD were determined using Kaplan-Meier methods. Results. Altogether, 65 (17.8%) patients were reoperated for ASD. The incidences of revisions for ASD in subgroups were 1) 4.8% (95% CI: 1.6%-22.1%); 2) 20.5% (95% CI: 15.6%-26.7%); 3) 20.6% (95% CI: 12.9%-31.9%). After adjusting the groups by age, sex, fusion length, and the level of the caudal end of fusion, when comparing with IS group, the other groups had significantly higher hazard ratios (HR) for the revision for ASD [2) HR (95% CI) 3.92 (1.10-13.96), P=0.035], [3) HR (95% CI) of 4.27 (1.11-15.54), P=0.036]. Conclusion. Among patients with IS, the incidence of revisions for ASD was less than a 4th of that with DLSD. Efforts to prevent the acceleration of the degenerative process at the adjacent level of fusion are most important with DLSD.publishedVersionPeer reviewe

Repeated cobalt and chromium ion measurements in patients with bilateral large-diameter head metal-on-metal ReCap-M2A-Magnum total hip replacement

Background and purpose: Whole-blood (WB) chromium (Cr) and cobalt (Co) measurements are vital in the follow-up of metal-on-metal total hip replacement (MoM THR) patients. We examined whether there is a substantial change in repeated WB, Co, and Cr levels in patients with bilateral ReCap-M2A-Magnum THR. We also specified the number of patients exceeding the safe upper limit (SUL) of WB Co and Cr in the repeated measurement.Patients and methods: We identified 141 patients with bilateral ReCap-M2A-Magnum THR operated in our institution. 61 patients had repeated WB metal ion measurements with bilateral MoM implants still in situ in the second measurement. The mean time elapsing from the first measurement (initial measurement) to the second (control measurement) was 1.9 years (SD = 0.6, range 0.2–3.5). We used earlier established SUL levels for bilateral implants by Van Der Straeten et al. (2013).Results: The median (range) Co and Cr values decreased in the repeated measurement from 2.7 (0.6–25) to 2.1 (0.5–21) and 2.6 (0.8–14) to 2.1 (0.5–18) respectively. In 13% of the patients Co levels exceeded the SUL in the initial measurement and the proportion remained constant, at 13%, in the repeated measurement. In 5% of the patients, Cr levels were above SUL in the initial measurement and an equal 5% in the control measurement.Interpretation: Repeated WB metal ion levels did not increase in patients with bilateral ReCap-M2A-Magnum THR with a mean 1.9-year measurement interval. Long-term development of WB metal ion levels is still unclear in these patients.</p

Incidence of lumbar discectomy during pregnancy and within 12 months post-partum in Finland between 1999 and 2017 : a retrospective register-based cohort study

BACKGROUND CONTEXT: Both lumbar disc herniation in the general population and lower back pain in the pregnant population are known to be common conditions. The physiological and anatomical of the mother predispose to increased strain of the lumbar disc, while pregnancy may promote caution in physicians contemplating surgical care. PURPOSE: We aimed to report the incidence of lumbar discectomy during pregnancy and 12 months post-partum in Finland between 1999 and 2017. STUDY DESIGN: Retrospective register-based cohort study. PATIENT SAMPLE: Using nationwide data from the Finnish Care Register for Health Care and the Finnish Medical Birth Register, all women aged 15 to 49 years with a lumbar discectomy or pregnancy ending in delivery from 1st January, 1999 to 31st December, 2017 were included. OUTCOME MEASURES: Incidence rates and their 95% confidence intervals were calculated for lumbar discectomy. Incidence rate ratios (IRR) were calculated between the study population and the control population. The effect of smoking on surgery risk was reported using odds ratios. METHODS: A retrospective statistical analysis was performed to identify patients undergoing lumbar discectomy during pregnancy or the first 12 months after delivery. Incidence rates were compared to the age-adjusted values of the age-matched female general population. The effect of smoking on the risk of lumbar discectomy was analysed using age-adjusted odds ratios. RESULTS: In total, 91 discectomies were performed during pregnancy and 508 within 12 months post-partum. The total incidence of lumbar discectomy during pregnancy was 11 operations per 100 000 person-years with an incidence rate ratio (IRR) of 0.2 (95% CI 0.1 to 0.2) when compared to the age-adjusted female general population. Women with active smoking before pregnancy were at a higher risk for lumbar discectomy during pregnancy (OR 2.0, 95% CI 1.2 to 3.2). Caesarean section was more common after lumbar discectomy (22%). No perinatal mortality was observed. During the first year post-partum the rate of lumbar discectomy increased to 47 per 100 000 person-years with an IRR of 0.7 (95% CI 0.6 to 0.8). 90-day reoperation rates were higher than in the general population with an IRR of 1.7 (95% CI 1.1 to 2.7). CONCLUSIONS: Lumbar discectomy during pregnancy is rare, but smoking increases the risk. Lumbar discectomy during pregnancy seems to be safe for the neonate. Post-partum incidences increased towards the end of the first year, but remained below the rates in the general population with a higher risk for short-term reoperation.publishedVersionPeer reviewe

Pregnancy and delivery after spine fracture or surgery : A nationwide population-based register study in Finland

BACKGROUND: The incidences of spine fractures and fusion surgeries have increased. A few studies have reported an increased rate of caesarean sections (CS) in women who have undergone spine surgery but have not reported on the health of neonates. OBJECTIVE: We report the incidence of spine fractures, spine fracture surgeries and fusion surgery for other reasons and the effect of these injuries and procedures on later pregnancy outcomes in Finland. METHODS: Data on all fertile-aged women (1998-2018) who had undergone spine fracture or spine fusion surgery were retrieved from the Care Register for Healthcare and combined with data from the National Medical Birth Register. Women with spine fracture or spine surgery before pregnancy were compared with women without previous spine fracture or surgery. We calculated incidences of spine fracture, spine fracture surgery and fusion surgery for other reasons with 95% confidence intervals (CI). We used multivariable logistic regression to evaluate CS and neonatal health. Results are reported as adjusted odds ratios (AOR). RESULTS: The main finding of our study was the increasing incidence (156%) of spine fusion surgeries for other reasons in fertile-aged women. A total CS rate (including elective and unplanned CS) in the spine fracture group was 19.7% (AOR 1.26, CI 1.17-1.34), in fusion surgery for other reasons group 25.3% (AOR 1.37, CI 1.30-1.49) and 15.9% in the control group. The rate for neonates requiring intensive care in the spine fracture group was 12.2% (AOR 1.18, CI 1.08-1.29), in fusion surgery for other reasons group 13.6% (AOR 1.12, CI 1.02-1.23) and 10.0% in the control group. CONCLUSIONS: The incidence of fusion surgery for other reasons increased during our study period. The rate of CS was higher in women with preceding spine fracture or fusion surgery. Our results suggest that vaginal delivery after fractures of the spine is both possible and safe for mother and neonate.publishedVersionPeer reviewe

Median 10-year whole blood metal ion levels and clinical outcome of ReCap-M2a-Magnum metal-on-metal total hip arthroplasty

Background and purposeWe have previously reported that the whole blood (WB) chromium (Cr) and cobalt (Co) ion levels decrease in the short term after ReCap-M2a-Magnum large-diameter head (LDH) metal-on-metal (MoM) total hip arthroplasty (THA). This study reports long-term metal ion levels and clinical outcomes after ReCap-Magnum THA.Patients and methodsReCap-M2a-Magnum LDH THA was used in 1,450 patients in our hospital district from 2005 to 2012. Median follow-up time was 10 years. 991 patients had 2 or more metal ion measurements. The median measurement interval was 4 years. Individual metal ion change was assessed using logarithmic metal ion values in a random coefficient model. Kaplan–Meier survival estimates were calculated for revision surgery for any reason for revision, and separately for metal-related adverse events (metalions above safe upper limit [SUL], revision due to ARMD, or pseudotumor).ResultsGeometric mean of Cr decreased from 1.8 ppb (geometric standard deviation [GSD] 1.8) to 1.0 ppb (GSD 2.8, p InterpretationWB Cr and Co levels continued to decrease in the long-term follow-up of ReCap-M2a-Magnum THA patients. The amount of metal-related adverse events was rather high, but revision surgery was seldom required. We suggest that after 10 years from the implantation a 5-year measurement interval may be sufficient for asymptomatic ReCap-M2a-Magnum patients.</p

Median 10-year whole blood metal ion levels and clinical outcome of ReCap-M2a-Magnum metal-on-metal total hip arthroplasty

BACKGROUND AND PURPOSE: We have previously reported that the whole blood (WB) chromium (Cr) and cobalt (Co) ion levels decrease in the short term after ReCap-M2a-Magnum large-diameter head (LDH) metal-on-metal (MoM) total hip arthroplasty (THA). This study reports long-term metal ion levels and clinical outcomes after ReCap-Magnum THA. PATIENTS AND METHODS: ReCap-M2a-Magnum LDH THA was used in 1,450 patients in our hospital district from 2005 to 2012. Median follow-up time was 10 years. 991 patients had 2 or more metal ion measurements. The median measurement interval was 4 years. Individual metal ion change was assessed using logarithmic metal ion values in a random coefficient model. Kaplan-Meier survival estimates were calculated for revision surgery for any reason for revision, and separately for metal-related adverse events (metal ions above safe upper limit [SUL], revision due to ARMD, or pseudotumor). RESULTS: Geometric mean of Cr decreased from 1.8 ppb (geometric standard deviation [GSD] 1.8) to 1.0 ppb (GSD 2.8, p < 0.001). The Co levels decreased from 1.7 ppb (GSD 2.4) to 1.4 ppb (GSD 2.8, p < 0.001). The hip-specific survival was 85% for revision due to any reason at 14 years and the hip-specific survival for any metal-related adverse event was 69% at 14 years. INTERPRETATION: WB Cr and Co levels continued to decrease in the long-term follow-up of ReCap-M2a-Magnum THA patients. The amount of metal-related adverse events was rather high, but revision surgery was seldom required. We suggest that after 10 years from the implantation a 5-year measurement interval may be sufficient for asymptomatic ReCap-M2a-Magnum patients.publishedVersionPeer reviewe

Isthmic Spondylolisthesis is Associated With Less Revisions for Adjacent Segment Disease After Lumbar Spine Fusion Than Degenerative Spinal Conditions : A 10-Year Follow-Up Study

Objective: We aim to compare the rate of revisions for adjacent segment disease (ASD) after lumbar spine fusion (LSF) surgery between patients with isthmic spondylolisthesis (IS) and degenerative lumbar spine disorders (DLSD). Summary of Background Data: ASD is a major reason for late reoperations after LSF surgery. Several risk factors are linked to the progression of ASD, but the understanding of the underlying mechanisms is imperfect. If IS infrequently becomes complicated with ASD, it would emphasize the role of the ongoing degenerative process in spine in the development of ASD. Methods: 365 consecutive patients that underwent elective LSF surgery were followed up for an average of 9.7 years. Surgical indications were classified into 1) IS (n=64), 2) DLSD (spinal stenosis with or without spondylolisthesis) (n=222), and 3) other reasons (deformities, postoperative conditions after decompression surgery, posttraumatic conditions) (n=79). All spinal reoperations were collected from hospital records. Rates of revisions for ASD were determined using Kaplan-Meier methods. Results: Altogether, 65 (17.8%) patients were reoperated for ASD. The incidences of revisions for ASD in subgroups were 1) 4.8% (95% CI: 1.6 to 22.1%); 2) 20.5% (95% CI: 15.6 to 26.7%); 3) 20.6% (95% CI: 12.9 to 31.9%). After adjusting the groups by age, sex, fusion length, and the level of the caudal end of fusion, when comparing with IS group, the other groups had significantly higher hazard ratios (HR) for the revision for ASD [2) HR (95% CI) 3.92 (1.10 to 13.96), p=0.035], [3) HR (95% CI) of 4.27 (1.11 to 15.54), p=0.036]. Conclusions: Among patients with IS, the incidence of revisions for ASD was less than a 4th of that with DLSD. Efforts to prevent the acceleration of the degenerative process at the adjacent level of fusion are most important with DLSD.peerReviewe

Repeated cobalt and chromium ion measurements in patients with large-diameter head metal-on-metal ReCap-M2A-Magnum total hip replacement

Background and purpose — Whole blood (WB) cobalt (Co) and chromium (Cr) ion levels have a major role in the follow-up of metal-on-metal total hip replacement (MoM THR). We investigated, first, if there was a change in WB Co or Cr levels over repeated measurements in patients with ReCap-M2A-Magnum THR, and, second, determined how many patients had WB Co or Cr levels that exceeded the safe upper limits (SUL) in the repeated whole blood metal ion assessment. Patients and methods — A Recap-M2A-Magnum THR was used in 1,329 operations (1,188 patients) at our institution between 2005 and 2012. We identified all patients (n = 319) with unilateral ReCap-M2A-Magnum implants who had undergone at least 2 repeated metal ion measurements with the first blood sample taken mean 5.5 years (1.8–9.3) after surgery and the second taken mean 2 years (0.5–3) after the first. Results — The median WB Co and Cr ion levels decreased in repeated measurements from 1.40 (0.40–63) ppb to 1.10 (0.20–68) ppb and from 1.60 (0.60–13.0) ppb to 1.10 (0.30–19.0) ppb, respectively. 7% of the Co ion values exceeded SUL at the initial measurement, and 7% at the control measurement. The proportion of Cr ion values exceeding the safe upper limit (SUL) decreased during the measurement interval from 5% to 4%. Interpretation — Repeated metal ion measurements in unilateral ReCap-M2A-Magnum patients in a mean 2-year time interval did not show any increase. Long-term ion levels are, however, not yet known