Complications after the Introduction of Well-Documented Components in Primary Total Hip Arthroplasty

Lonkan tekonivelleikkaus on yleensä menestyksekäs toimenpide joka vähentää kipua ja parantaa potilaan liikuntakykyä. Lonkan tekonivelleikkauksen tulokset ovat jatkuvasti parantuneet vuosikymmeniä jatkuneen komponenttien ja leikkaustekniikoiden kehittymisen ansiosta. Kuitenkin uusien komponenttien käyttöönoton seurauksena saattaa ilmetä odotettua enemmän komplikaatioita. Yleisimmät vakavat komplikaatiot lonkan tekonivelleikkauksen jälkeen ovat lonkkaproteesin sijoiltaanmeno eli luksaatio, tekonivelinfektio ja periproteettinen murtuma. Luksaatioalttiit potilaat saattavat hyötyä komponenteista, jotka on suunniteltu ehkäisemään sijoiltaanmenoja, kuten dual-mobility -kupista tai lukkomekanismin sisältävästä lineristä. Näitä aiemmin lähinnä uusintaleikkauksissa hyödynnettyjä komponentteja käytetään nykyään enenevästi jo ensitekonivel- leikkauksissa. Korkean murtumariskin potilailla on jo pidempää suosittu sementillistä varsikomponenttejaa, johon liittyy pienempi periproteettisen murtuman riski. Euroopan Unionin alueella sairaaloilla on velvollisuus kilpailuttaa säännöllisesti käyttämänsä tekonivelkomponentit julkisten varojen käytön tehostamiseksi ja eurooppalaisten yritysten kilpailukyvyn parantamiseksi. Todennäköisesti uusia komponentteja otetaan siis käyttöön säännöllisesti eurooppalaisissa sairaaloissa. Tekonivelsairaala Coxassa uudet tekonivelkomponentit otettiin käyttöön kilpailutusprosessin jälkeen huhtikuussa 2016. Kyseiset komponentit olivat tunnettuja ja niiden tulokset aiemmissa tutkimuksissa olivat olleet hyviä. Tämän väitöskirjan tavoite oli tutkia komplikaatiota, joita ilmeni näiden tunnettujen implanttien käyttöönoton jälkeen, sekä keinoja luksaatioiden ehkäisyksi. Ensimmäisessä osatyössä verrattiin aiemmin käytössä olleen Pinnacle-kupin ja uutena käyttöön otetun Continuum-kupin välistä luksaation riskiä. Toisessa osatyössä verrattiin periproteettisen murtuman esiintyvyyttä ja yleistä revision riskiä aiemmin käytetyn sementillisen Exeter-varren ja uutena käyttöönotetun sementillisen CPT-varren välillä, jotka molemmat ovat nk. taper-slip -varsia. Kolmannessa osatyössä rakennettiin varhaiselle luksaation vuoksi tehdylle revisiolle kaksi ennustemallia kahden erilaisen tilastollisen menetelmän pohjalta (perinteinen logistinen regressio ja koneoppimista hyödyntävä elastic net -menetelmä). Kolmen ensimmäisen osatyön aineistot pohjautuivat Coxan omaan tietokantaan. Neljännessä osatyössä selvitettiin lonkan ensitekonivelleikkauksessa käytettyihin dual-mobility - kuppeihin ja lukollisiin linereihin liittyvää uusintaleikkauksen kumulatiivista ilmaantuvuutta, ja selvitettiin tekonivelnupin koon vaikutusta lukollisten linerien tuloksiin Suomen Tekonivelrekisterin datassa. Verrokkiryhmänä tässä tutkimuksessa toimi iso kohortti perinteiset tekonivelkomponentit saaneita potilaita. Ensimmäisessä osatyössä havaittiin, että jopa 5.1% potilaista, joille oli asennettu uutena käyttöönotettu Continuum-merkkinen kuppi neutraalin linerin kanssa sai varhaisen luksaation. Monimuuttuja-analyysissä luksaatioriski oli korkeampi potilailla, jotka olivat saaneet Continuum-kupin ja neutraalin linerin verrattuna potilaisiin jotka saivat aiemmin käytössä olleen Pinnacle-kupin (odds ratio 4.8, 95% luottamusväli [LV95] 1.4-17). Sen sijaan kun Continuum-kuppia käytettiin reunakorotuksellisen elevated rim -linerin kanssa, luksaatioriski oli samaa tasoa Pinnacleen verrattuna (odds ratio 1.2, LV95 0.2-7.8). Toisessa osatyössä todettiin, että periproteettinen murtuma oli yleisin syy uusintaleikkaukselle potilailla, joilla käytettiin taper-slip -varsia. Periproteettinen murtuma kattoi 35% uusinta- leikkauksista jotka tehtiin 2 vuoden sisällä ensileikkauksesta. Periproteettisen murtuman esiintyvyys 2 vuoden kohdalla ensileikkauksesta oli 1.6% (LV95 1.0-2.4) CPT-varrella ja 1.0% (LV95 0.6-1.6) Exeter-varrella. CPT-varren käyttö lisäsi yleistä uusintaleikkauksen riskiä Exeter-varteen verrattuna (hazard ratio 1.8, LV95 1.2-2.7). Kolmannessa osatyössä molempien ennustemallien ennustekyky oli heikko ja erottelukyky kohtalainen. Mallien välillä ei ollut merkittävää eroa. Logistista regressiota hyödyntävässä mallissa varsikomponentin kiinnitystapa, epilepsialääkkeiden käyttö ja ensileikkauksen indikaatio olivat tärkeimmät ennustetekijät varhaiselle luksaation vuoksi tehdylle uusintaleikkaukselle. Neljännessä osatyössä ensileikkauksessa dual-mobility -kupin tai 36 mm:n nuppikoon lukollisen linerin saaneiden potilaiden uusintaleikkausriskin todettiin olevan samaa luokkaa kuin perinteiset tekonivelkomponentit saaneilla potilailla. Näiden ryhmien potilaista hyvin harva uusintaleikattiin luksaation vuoksi, vaikka erikoiskomponentin saaneet potilaat olivat keskimäärin monisairaampia ja alttiimpia komplikaatioille. Sen sijaan potilaista, jotka olivat saaneet pienempään (22-32 mm) nuppiin kombinoidun lukollisen linerin, huomattavasti suurempi osa uusintaleikattiin seuranta-aikana, ja tässä ryhmässä luksaatio oli yleisin uusintaleikkauksen syy. Uusien komponenttien käyttöönotto johti kohonneeseen luksaatioriskin ja suurempaan yleiseen uusintaleikkauksen riskiin suuren leikkausvolyymin tekonivelkirurgian yksikössämme. Kohonnut luksaatioriski selittyi Continuum-kupin neutraalin linerin heikolla kattavuudella, joka altisti sijoiltaanmenoille. Siksi elevated rim -mallista lineria tulisi käyttää rutiinisti Continuum-kupin kanssa. Taper slip - tyyppisiä varsia, erityisesti CPT:tä, tulisi välttää potilailla joilla on kohonnut periproteettisen murtuman riski. Kun uusia implantteja otetaan käyttöön, leikkaustuloksia tulisi tarkkailla erityisen huolellisesti, sillä yllättävän paljon komplikaatioita saattaa ilmetä, vaikka käyttöönotetut komponentit olisivat hyvin dokumentoituja ja olisivat saaneet hyviä tuloksia aiemmissa tutkimuksissa. Koska luksaatio on harvinainen ja monitekijäinen komplikaatio, luksaation vuoksi tehdyn uusintaleikkauksen ennustaminen on vaikeaa, vaikka ennustemalli rakennettaisiin ison potilasjoukon ja yksityiskohtaisten potilastietojen pohjalta, eikä monimutkaisten tilastollisten menetelmien hyödyntäminen tuo tällöin välttämättä merkittävää etua. Dual-mobility -kuppien käyttö korkean luksaatioriskin potilailla lonkan ensitekonivelleikkauksessa voidaan katsoa perustelluksi sekä tämän tutkimuksen tulosten että myös aiempien julkaisujen pohjalta, mutta pitkän aikavälin seurantatuloksia on julkaistu vasta niukasti. Suuremman tekonivelnupin käyttö lukollisen linerin kanssa saattaa pienentää uusintaleikkauksen riskiä, mahdollisesti pienemmän luksaatioriskin vuoksi. Siksi 36 mm:n nuppeja tulisi suosia potilailla, jotka tarvitsevat lukollisen linerin.Total hip arthroplasty (THA) is usually a very successful procedure that reduces pain and improves patients’ physical abilities. The results after THA have improved thanks to decades of development in implant designs and surgical techniques. However, there is always a risk for unexpectedly high complication rates when new components are introduced in a new institution. Currently, the most common major complication types in THA are prosthesis dislocation, periprosthetic infection, and periprosthetic femoral fracture (PFF). For dislocation-prone patients, unconventional implants that offer extra stability, such as dual-mobility cups and constrained liners, are increasingly being used in primary THA. In patients at high risk for PFF, cemented stems are preferred. Hospitals in the European Union are legally obligated to go through tendering processes frequently to increase the efficiency of the use of public funds and to improve the competitiveness of European companies. Thus, the introduction of new THA components is likely a frequent event in European hospitals. At Coxa Hospital for Joint Replacement, new THA implants were introduced after completion of a tendering process in April 2016. These were all well-documented implants with good scientific track records. The aim of this dissertation was to investigate complications after the introduction of well-documented components at our institution and to study the prevention of dislocation after primary THA. In Study I, the risk for dislocation was assessed between the previously used Pinnacle and the recently introduced Continuum cup systems. In Study II, the prevalence of revision for PFF and the risk for all-cause revision were compared between the previously used cemented Exeter stem and the recently introduced cemented CPT stem, which are both classified as ‘taper-slip stems’. In Study III, two prediction models employing different statistical approaches (traditional logistic regression and elastic net method that utilizes machine learning) were built with early revision for dislocation as the outcome. Studies I-III were based on Coxa’s own database. In Study IV, the survivorship of the dual-mobility cups and constrained liners used in primary THA and the effect of femoral head size on the survivorship of constrained liners were investigated from Finnish Arthroplasty Register data, with a large cohort of conventional primary THA patients as a reference group. In Study I, a high prevalence of early dislocation (5.1%) was found with the newly introduced Continuum cup when it was used with a neutral liner. Compared with the previously used Pinnacle cup system, the risk for dislocation was higher in the Continuum cup used with a neutral liner (odds ratio 4.8, 95% confidence interval [CI] 1.4-17), but similar in the Continuum cup used with an elevated rim liner (odds ratio 1.2, CI 0.2-7.8). In Study II, PFF was the most common reason for revision, covering 35% of all revisions during the first two postoperative years. The 2-year prevalence of PFF revision was 1.6% (CI 1.0-2.4) for the CPT stem and 1.0% (CI 0.6-1.6) for the Exeter stem. The use of the CPT stem increased the overall risk for revision compared with the use of the Exeter stem (hazard ratio 1.8, CI 1.2-2.7). In Study III, the predictive capability of both prediction models was low, and the discrimination of both models was moderate. In the logistic regression model, femoral fixation method, use of antiepileptic drugs, and the primary reason for operation were the most important predictors of revision for dislocation. In Study IV, the survivorship of the dual-mobility cups and constrained liners used with a large (36 mm) diameter femoral head was comparable with or only slightly lower than conventional THA implants even though the patients who received these unconventional implants were on average severely more morbid, and therefore more vulnerable to complications. In these study groups, only a few revisions for dislocation occurred. However, the constrained liners used with smaller (22-32 mm) femoral heads had a clearly higher revision rate, mostly due to a high rate of revisions for dislocation. The introduction of new primary THA components led to an increased risk for dislocation and a higher risk for revision in our high-volume academic joint replacement hospital. The higher risk for dislocation was explained by the weaker coverage of the recently introduced Continuum’s neutral liner compared with the previously used Pinnacle neutral liner. Therefore, the routine use of an elevated rim liner with the Continuum cup is recommended. Because the risk for PFF seems to be a concern with taper-slip stems, especially the CPT, the consideration of other stem designs for high-risk patients in primary THA is encouraged. Moreover, when new implants are introduced, the results should be carefully monitored because unexpectedly high complication rates may occur even though the implants are well- documented and have a good scientific track-record. Because dislocation is a quite rare and multifactorial event, the prediction of an early dislocation revision after primary THA is very difficult, even with a large cohort of patients and specific data available. Moreover, the use of sophisticated methods that utilize machine learning may not necessarily offer significant advantage. Our results, along with the recent literature, support the increased use of DMCs for dislocation-prone patients in primary THA. Still, more long-term results are needed before the use of these implants becomes more widespread. Also, it seems that enlarging the femoral head with CLs enhances the survival of the implant, potentially because of the decreased risk for dislocations. Therefore, it is recommended that a 36 mm femoral head is preferred when a CL is used

Incidence of football injuries sustained on artificial turf compared to grass and other playing surfaces : a systematic review and meta-analysis

Background: Prior reviews have not conducted statistical synthesis of injury incidence on artificial turf in football. To analyse and compare the incidence of injuries sustained playing football (soccer) on artificial turf compared to grass and other playing surfaces. Methods: This was a systematic review and meta-analysis. We searched PubMed, Scopus, SPORTDiscus, and Web of Science databases in October 2022 without filters. All observational studies (prospective or retrospective) that analysed injuries sustained playing football on artificial turf and which included a control group that played on grass or other surface were included. Studies were included if they reported the number of injuries and the exposure time for the playing surfaces. Risk of bias was assessed by Newcastle-Ottawa Scale. A random effects model was used to calculate the pooled incidence rate ratios (IRR) with 95% confidence intervals. Protocol was registered with PROSPERO on October 30th, 2022. Registration number: CRD42022371414. Findings: We screened 1447 studies, and evaluated 67 full reports, and finally included 22 studies. Risk of bias was a notable issue, as only 5 of the 22 studies adjusted their analysis for potential confounders. Men (11 studies: IRR 0.82, CI 0.72–0.94) and women (5 studies: IRR 0.83, CI 0.76–0.91) had lower injury incidence on artificial turf. Professional players had a lower incidence of injury (8 studies: IRR 0.79, CI 0.70–0.90) on artificial turf, whereas there was no evidence of differences in the incidence of injury in amateur players (8 studies: IRR 0.91, CI 0.77–1.09). The incidence of pelvis/thigh (10 studies: IRR 0.72, CI 0.57–0.90), and knee injuries (14 studies: IRR 0.77, CI 0.64–0.92) were lower on artificial turf. Interpretation: The overall incidence of football injuries is lower on artificial turf than on grass. Based on these findings, the risk of injury can't be used as an argument against artificial turf when considering the optimal playing surface for football. Funding: No specific funding was received for this study.publishedVersionPeer reviewe

Prediction model for an early revision for dislocation after primary total hip arthroplasty

Dislocation is one of the most common complications after primary total hip arthroplasty (THA). Several patient-related risk factors for dislocation have been reported in the previous literature, but only few prediction models for dislocation have been made. Our aim was to build a prediction model for an early (within the first 2 years) revision for dislocation after primary THA using two different statistical methods. The study data constituted of 37 pre- or perioperative variables and postoperative follow-up data of 16 454 primary THAs performed at our institution in 2008–2021. Model I was a traditional logistic regression model and Model II was based on the elastic net method that utilizes machine learning. The models’ overall performance was measured using the pseudo R2 values. The discrimination of the models was measured using C-index in Model I and Area Under the Curve (AUC) in Model II. Calibration curves were made for both models. At 2 years postoperatively, 95 hips (0.6% prevalence) had been revised for dislocation. The pseudo R2 values were 0.04 in Model I and 0.02 in Model II indicating low predictive capability in both models. The C-index in Model I was 0.67 and the AUC in Model II was 0.73 indicating modest discrimination. The prediction of an early revision for dislocation after primary THA is difficult even in a large cohort of patients with detailed data available because of the reasonably low prevalence and multifactorial nature of dislocation. Therefore, the risk of dislocation should be kept in mind in every primary THA, whether the patient has predisposing factors for dislocation or not. Further, when conducting a prediction model, sophisticated methods that utilize machine learning may not necessarily offer significant advantage over traditional statistical methods in clinical setup.publishedVersionPeer reviewe

Implant survival of 662 dual-mobility cups and 727 constrained liners in primary THA: small femoral head size increases the cumulative incidence of revision

Background and purpose - In total hip arthroplasty (THA), the risk for dislocation can be reduced using either dual-mobility cups (DMCs) or constrained liners (CLs). There are few studies comparing these concepts in primary THA. Therefore, we compared the cumulative incidence of revision in primary THA patients treated with DMC or CL with varying head sizes with conventional THA patients as reference group. Patients and methods - We performed a cohort study based on the Finnish arthroplasty register, comparing DMCs and CLs operated over the period 2000-2017. DMCs were divided into 2 groups based on the implant design: "DMC Trident" group (n = 399) and "DMC Others" group (n = 263). CLs were divided based on the femoral head size: "CL 36 mm" group (n = 425) and "CL < 36 mm" group (n = 302). All conventional primary THAs operated on in 2000-2017 with 28-36 mm femoral head were included as control group ("Conventional THA" group, n = 102,276). Implant survival was calculated by the corresponding cumulative incidence function with revision as the endpoint and death as competing event. Also, the prevalence of different reasons for revision was compared. Results - The 6-year cumulative incidence function estimates for the first revision were 6.9% (95% CI 4.0-9.7) for DMC Trident, 5.0% (CI 1.5-8.5) for DMC Others, 13% (CI 9.3-17) for CL < 36 mm, 6.3% (3.7-8.9) for CL 36 mm, and 4.7% (CI 4.5-4.8) for control group (conventional THA). The prevalence of dislocation revision was high (5.0%, CI 2.9-8.2) in the CL < 36 mm group compared with other groups. Interpretation - The DMC and CL 36 mm groups had promising mid-term survival rates, comparable to those of primary conventional THA group. The revision rate of CLs with < 36 mm head was high, mostly due to high prevalence of dislocation revisions. Therefore, CLs with 36 mm femoral head should be preferred over smaller ones

Speed and Nighttime Usage Restrictions and the Incidence of Shared Electric Scooter Injuries

Importance: Electric scooter (e-scooter) crashes have become a serious health issue worldwide. The need for effective e-scooter regulations has been established in numerous instances. Objective: To investigate the association of restrictions on top speed and nighttime usage on the incidence of e-scooter-related injuries. Design, Setting, and Participants: A retrospective comparative cohort study of all patients with an injury related to shared e-scooter riding sustained in Helsinki, Finland. Data were collected from the electric patient database from 3 trauma hospitals representing all public hospitals treating patients with acute trauma in Helsinki. Shared e-scooter injuries from 2 periods were compared: an unrestricted period (January 1 to August 31, 2021) and a restricted period (January 1 to August 31, 2022). Data were analyzed from September 2022 to September 2023. Exposures: The restrictions established for shared e-scooters during the restricted period were: (1) the daytime top speed of 20 km/h, as opposed to the previous top speed of 25 km/h, (2) the use of shared e-scooters was prohibited on Friday and Saturday nights between 12 am and 5 am, and (3) the nighttime top speed was decreased to 15 km/h from Sunday to Thursday between 12 am and 5 am, as opposed to 25 km/h. Main outcome: The incidence of e-scooter injuries compared with the total trips made by e-scooters. Results: There were 528 e-scooter injuries requiring hospital care during the unrestricted period and 318 injuries during the restricted period of similar length. The median (IQR) age of the patients in the study periods was 25 (21-32) and 28 (22-37), respectively; 308 (58%) and 191 (60%) were male, respectively. The incidence of e-scooter injuries was 19 (95% CI, 17-20) for every 100000 rides during the unrestricted period and 9 (95% CI, 8-10) per 100000 rides during the restricted period. In the risk analysis, the odds ratio for shared e-scooter injuries was 0.5 (95% CI, 0.4-0.6) for the restricted period when adjusted for hourly temperature, rain amount, wind speed, and visibility. After introducing the restrictions, the number of e-scooter injuries decreased significantly between 11 pm and 5 am. Conclusion and Relevance: The number of injuries decreased after implementing restrictions on the top speed and nighttime usage of e-scooters. Similar restrictions in cities with shared e-scooter services should be explored.Peer reviewe

A comparison of different selective ultrasound screening strategies for developmental dysplasia of the hip

Aims To analyze whether the addition of risk -based criteria to clinical examination -based selec-tive ultrasound screening would increase the rates of early detected cases of developmen-tal dysplasia of the hip (DDH) and decrease the rate of late detected cases.Methods A systematic review with meta-analysis was performed. The initial search was performed in the PubMed, Scopus, and Web of Science databases in November 2021. The following search terms were used: (hip) AND (ultrasound) AND (luxation or dysplasia) AND (newborn or neonate or congenital).Results A total of 25 studies were included. In 19 studies, newborns were selected for ultrasound based on both risk factors and clinical examination. In six studies, newborns were selected for ultrasound based on only clinical examination. We did not find evidence indicating that there are differences in the incidence of early-and late-detected DDH, or in the incidence of nonoperatively treated DDH between the risk -based and clinical examination -based groups. The pooled incidence of operatively treated DDH was slightly lower in the risk -based group (0.5 (95% confidence interval (CI) 0.3 to 0.7)) compared with the clinical exami- nation group (0.9 per 1,000 newborns, (95% CI 0.7 to 1.0)).Conclusion The use of risk factors in conjunction with clinical examination in the selective ultrasound screening of DDH might lead to fewer operatively treated cases of DDH. However, more studies are needed before stronger conclusions can be drawn.Peer reviewe

Implant survival of 662 dual-mobility cups and 727 constrained liners in primary THA : small femoral head size increases the cumulative incidence of revision

Background and purpose — In total hip arthroplasty (THA), the risk for dislocation can be reduced using either dual-mobility cups (DMCs) or constrained liners (CLs). There are few studies comparing these concepts in primary THA. Therefore, we compared the cumulative incidence of revision in primary THA patients treated with DMC or CL with varying head sizes with conventional THA patients as reference group. Patients and methods — We performed a cohort study based on the Finnish arthroplasty register, comparing DMCs and CLs operated over the period 2000–2017. DMCs were divided into 2 groups based on the implant design: “DMC Trident” group (n = 399) and “DMC Others” group (n = 263). CLs were divided based on the femoral head size: “CL 36 mm” group (n = 425) and “CL < 36 mm” group (n = 302). All conventional primary THAs operated on in 2000–2017 with 28–36 mm femoral head were included as control group (“Conventional THA” group, n = 102,276). Implant survival was calculated by the corresponding cumulative incidence function with revision as the endpoint and death as competing event. Also, the prevalence of different reasons for revision was compared. Results — The 6-year cumulative incidence function estimates for the first revision were 6.9% (95% CI 4.0–9.7) for DMC Trident, 5.0% (CI 1.5–8.5) for DMC Others, 13% (CI 9.3–17) for CL < 36 mm, 6.3% (3.7–8.9) for CL 36 mm, and 4.7% (CI 4.5–4.8) for control group (conventional THA). The prevalence of dislocation revision was high (5.0%, CI 2.9–8.2) in the CL < 36 mm group compared with other groups. Interpretation — The DMC and CL 36 mm groups had promising mid-term survival rates, comparable to those of primary conventional THA group. The revision rate of CLs with < 36 mm head was high, mostly due to high prevalence of dislocation revisions. Therefore, CLs with 36 mm femoral head should be preferred over smaller ones.publishedVersionPeer reviewe