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

Nissenin fundoplikaation pitkäaikaistulokset

Refluksitaudista on tullut yleisin mahasuolikanavan sairaus länsimaissa. Tällä hetkellä valtamenetelmänä oleva kirurginen hoito, Nissenin fundoplikaatio, kehitettiin alun perin vuonna 1955, ja ensimmäinen tähystysavusteinen fundoplikaatio tehtiin vuonna 1991. Vaikka leikkausmenetelmä on jo 60 vuotta vanha, pitkäaikaistuloksia, jotka kuvaavat menetelmän käyttöä valikoimattomissa potilasaineistoissa, on julkaistu vähän. Pisimmät seurantatutkimukset rajoittuvat ylipäätään 20 vuoteen. Tämä väitöskirjatyö koostuu neljästä vertaisarvioidusta alkuperäisartikkelista. Ensimmäisessä osatyössä (I) tavoitteemme oli kuvata leikkaushoidon aiheet, leikkaustekniikka sekä vuotuiset leikkausmäärät Kanta-Hämeen keskussairaalassa tähystysavusteisen leikkaustekniikan käyttöönoton jälkeen. Tuloksiemme mukaan leikkausmäärät lisääntyivät merkittävästi tähystysleikkausten myötä. Vaikka leikkausaiheena oli objektiivisilla tutkimusmenetelmillä todettu refluksitauti, leikkausmäärän kasvamisen katsottiin johtuvan leikkausaiheiden laajenemisesta koskemaan suurempaa potilasjoukkoa. Leikkaustekniikka kehittyi standardoidummaksi 90-luvun loppua kohti. Toinen (II) ja kolmas (III) osatyömme käsittelivät Kanta-Hämeen keskussairaalassa tähystysavusteisesti fundoplikaatio-leikattujen potilaiden pitkäaikaistuloksia. Toisessa (II) osatyössä tavoitteemme oli määritellä leikkauspotilaiden elämänlaatu kymmenen vuotta leikkauksen jälkeen. Kolmannessa (III) osatyössä halusimme selvittää leikkaustuloksen kestävyyttä valikoimattomassa potilasaineistossa, fibriiniliiman vaikutusta leikkaustulokseen sekä potilaiden oireilua ja tyytyväisyyttä. Tutkimustemme mukaan leikkauspotilaiden elämänlaatu oli lähes vastaava kuin suomalaisella verrokkiväestöllä. Suurin osa potilaista oli tyytyväisiä leikkaustulokseen, mutta tyytymättömyys oli yhteydessä alentuneeseen elämänlaatuun. Ilmavaivat ja nielemisvaikeudet olivat yleisimpiä hoitoon liittyviä sivuvaikutuksia, ja nielemisvaikeudet olivat yleisin ongelma tyytymättömillä potilailla. Ehjiksi todettiin 89 % fundoplikaatio-manseteista, ja vain 6 % potilaista ilmoitti olevansa tyytymättömiä leikkaustulokseen. Subjektiivisten ja objektiivisten tulosten katsottiin olevan vastaavat kuin aiemmin raportoidut, pidemmälle erikoistuneista yksiköistä julkaistut tulokset. Ensimmäistä kertaa fibriiniliiman käytön vaikutus yhdistettiin leikkaustuloksen pettämistä vähentäväksi tekijäksi pitkäaikaisseurannassa. Neljännessä (IV) osatyössä halusimme selvittää Tampereen yliopistollisessa sairaalassa yli kolmekymmentä vuotta aiemmin avomenetelmällä leikattujen potilaiden subjektiiviset leikkaustulokset, elämänlaadun sekä ennen tähystysaikakautta käytössä olleet leikkausaiheet. Tuloksemme antavat viitteitä siitä, että onnistuneen Nissenin fundoplikaatio leikkauksen jälkeen potilaat saattavat saada elinikäisen avun refluksioireiluun. Potilaiden elämänlaatu todettiin vastaavaksi kuin suomalaisen verrokkiväestön yli kolmekymmentä vuotta leikkauksen jälkeen. Leikkausaiheiden katsottiin heijastavan 80-luvulla vallinneita käytäntöjä. Suurimmalla osalla potilaista oli objektiivisesti varmistettu refluksitauti. Tähystysavusteisella Nissenin fundoplikaatiolla on saavutettavissa kestävä leikkaustulos myös valikoimattomissa potilasaineistoissa. Onnistuneella leikkaustuloksella on mahdollisesti saavutettavissa elinikäinen helpotus refluksioireiluun, mutta leikkaukseen liittyvät potentiaaliset riskit ja sivuvaikutukset on otettava huomioon mietittäessä kirurgista hoitoa hoitovaihtoehtona. Sekä kirurgit että potilaat voivat hyödyntää tämän väitöskirjan tuloksia arvioidessaan hoitoon liittyviä hyötyjä ja haittoja.Gastroesophageal reflux disease has become the most common gastrointestinal disorder in the Western world. The currently prevailing surgical treatment, Nissen fundoplication, was originally developed in 1955, and the laparoscopic technique was utilized for the first time in 1991. There are few pragmatic studies presenting long-term results of laparoscopic Nissen fundoplication from routine clinical practice, and even though the treatment method is 60 years old, the longest follow-up studies are limited to 20 years. This thesis consists of four independent articles. The aim of our first study (I) was to describe the indications, operative technique, and annual rates of antireflux surgery at Kanta-Häme Central Hospital after the dissemination of the laparoscopic technique. The results showed that, after the introduction of the laparoscopic technique, the number of antireflux operations rose markedly. Although only patients with objectively verified GERD were treated, the rise in the operation rates was considered to be a result of the broadening of the indications to include a wider range of patients. The operative technique became more standardized towards the end of the 1990s. Our second (II) and third (III) articles concerned the long-term results of laparoscopic Nissen fundoplication at Kanta-Häme Central Hospital. In our second study (II), the aim was to define the ten-year results as regards the health-related quality of life of our patient cohort. The objective of our third study (III) was to describe the long-term durability of surgical results in routine clinical practice, the impact of fibrin glue on the incidence of surgical failure, and the subjective outcomes ten years after the operation. We found that the health-related quality of life of the patient cohort was close to that of the Finnish general population. The patient satisfaction was high, but dissatisfaction with the treatment was associated with the decreased health-related quality of life. Flatulence and dysphagia were the most common side effects of the treatment, while dysphagia was the most common problem among the dissatisfied. Eighty-nine percent of the fundoplication wraps were intact, and only 6% of the patients were unsatisfied with the results. The subjective and objective long-term results were comparable to those published from more specialized centers. For the first time, it was noted that the use of fibrin glue seemed to decrease the incidence of defective fundoplication wraps in the long term. In our fourth (IV) article, we aimed to present almost lifelong follow-up (>30 years) after open Nissen fundoplication in terms of subjective outcomes and health-related quality of life and to describe the indications for antireflux surgery before the laparoscopic era. According to our results, a successful Nissen fundoplication may provide a lifelong control of reflux symptoms, and the health-related quality of life of the patients was comparable to that of the general population over 30 years after the operation. The indications for the procedure reflected the practices of the time, and, in most of the patients, GERD was objectively verified. The results of this thesis suggest that laparoscopic Nissen fundoplication can provide durable surgical results in routine clinical practice as well. In the case of successful surgery, fundoplication may give the patient a lifelong relief of reflux symptoms, but the potential risks and treatment-related side effects should be weighed cautiously when considering operative treatment. These results provide information for physicians and patients when weighing the benefits and harms of the treatment

Nissenin fundoplikaation pitkäaikaistulokset

Refluksitaudista on tullut yleisin mahasuolikanavan sairaus länsimaissa. Tällä hetkellä valtamenetelmänä oleva kirurginen hoito, Nissenin fundoplikaatio, kehitettiin alun perin vuonna 1955, ja ensimmäinen tähystysavusteinen fundoplikaatio tehtiin vuonna 1991. Vaikka leikkausmenetelmä on jo 60 vuotta vanha, pitkäaikaistuloksia, jotka kuvaavat menetelmän käyttöä valikoimattomissa potilasaineistoissa, on julkaistu vähän. Pisimmät seurantatutkimukset rajoittuvat ylipäätään 20 vuoteen. Tämä väitöskirjatyö koostuu neljästä vertaisarvioidusta alkuperäisartikkelista. Ensimmäisessä osatyössä (I) tavoitteemme oli kuvata leikkaushoidon aiheet, leikkaustekniikka sekä vuotuiset leikkausmäärät Kanta-Hämeen keskussairaalassa tähystysavusteisen leikkaustekniikan käyttöönoton jälkeen. Tuloksiemme mukaan leikkausmäärät lisääntyivät merkittävästi tähystysleikkausten myötä. Vaikka leikkausaiheena oli objektiivisilla tutkimusmenetelmillä todettu refluksitauti, leikkausmäärän kasvamisen katsottiin johtuvan leikkausaiheiden laajenemisesta koskemaan suurempaa potilasjoukkoa. Leikkaustekniikka kehittyi standardoidummaksi 90-luvun loppua kohti. Toinen (II) ja kolmas (III) osatyömme käsittelivät Kanta-Hämeen keskussairaalassa tähystysavusteisesti fundoplikaatio-leikattujen potilaiden pitkäaikaistuloksia. Toisessa (II) osatyössä tavoitteemme oli määritellä leikkauspotilaiden elämänlaatu kymmenen vuotta leikkauksen jälkeen. Kolmannessa (III) osatyössä halusimme selvittää leikkaustuloksen kestävyyttä valikoimattomassa potilasaineistossa, fibriiniliiman vaikutusta leikkaustulokseen sekä potilaiden oireilua ja tyytyväisyyttä. Tutkimustemme mukaan leikkauspotilaiden elämänlaatu oli lähes vastaava kuin suomalaisella verrokkiväestöllä. Suurin osa potilaista oli tyytyväisiä leikkaustulokseen, mutta tyytymättömyys oli yhteydessä alentuneeseen elämänlaatuun. Ilmavaivat ja nielemisvaikeudet olivat yleisimpiä hoitoon liittyviä sivuvaikutuksia, ja nielemisvaikeudet olivat yleisin ongelma tyytymättömillä potilailla. Ehjiksi todettiin 89 % fundoplikaatio-manseteista, ja vain 6 % potilaista ilmoitti olevansa tyytymättömiä leikkaustulokseen. Subjektiivisten ja objektiivisten tulosten katsottiin olevan vastaavat kuin aiemmin raportoidut, pidemmälle erikoistuneista yksiköistä julkaistut tulokset. Ensimmäistä kertaa fibriiniliiman käytön vaikutus yhdistettiin leikkaustuloksen pettämistä vähentäväksi tekijäksi pitkäaikaisseurannassa. Neljännessä (IV) osatyössä halusimme selvittää Tampereen yliopistollisessa sairaalassa yli kolmekymmentä vuotta aiemmin avomenetelmällä leikattujen potilaiden subjektiiviset leikkaustulokset, elämänlaadun sekä ennen tähystysaikakautta käytössä olleet leikkausaiheet. Tuloksemme antavat viitteitä siitä, että onnistuneen Nissenin fundoplikaatio leikkauksen jälkeen potilaat saattavat saada elinikäisen avun refluksioireiluun. Potilaiden elämänlaatu todettiin vastaavaksi kuin suomalaisen verrokkiväestön yli kolmekymmentä vuotta leikkauksen jälkeen. Leikkausaiheiden katsottiin heijastavan 80-luvulla vallinneita käytäntöjä. Suurimmalla osalla potilaista oli objektiivisesti varmistettu refluksitauti. Tähystysavusteisella Nissenin fundoplikaatiolla on saavutettavissa kestävä leikkaustulos myös valikoimattomissa potilasaineistoissa. Onnistuneella leikkaustuloksella on mahdollisesti saavutettavissa elinikäinen helpotus refluksioireiluun, mutta leikkaukseen liittyvät potentiaaliset riskit ja sivuvaikutukset on otettava huomioon mietittäessä kirurgista hoitoa hoitovaihtoehtona. Sekä kirurgit että potilaat voivat hyödyntää tämän väitöskirjan tuloksia arvioidessaan hoitoon liittyviä hyötyjä ja haittoja.Gastroesophageal reflux disease has become the most common gastrointestinal disorder in the Western world. The currently prevailing surgical treatment, Nissen fundoplication, was originally developed in 1955, and the laparoscopic technique was utilized for the first time in 1991. There are few pragmatic studies presenting long-term results of laparoscopic Nissen fundoplication from routine clinical practice, and even though the treatment method is 60 years old, the longest follow-up studies are limited to 20 years. This thesis consists of four independent articles. The aim of our first study (I) was to describe the indications, operative technique, and annual rates of antireflux surgery at Kanta-Häme Central Hospital after the dissemination of the laparoscopic technique. The results showed that, after the introduction of the laparoscopic technique, the number of antireflux operations rose markedly. Although only patients with objectively verified GERD were treated, the rise in the operation rates was considered to be a result of the broadening of the indications to include a wider range of patients. The operative technique became more standardized towards the end of the 1990s. Our second (II) and third (III) articles concerned the long-term results of laparoscopic Nissen fundoplication at Kanta-Häme Central Hospital. In our second study (II), the aim was to define the ten-year results as regards the health-related quality of life of our patient cohort. The objective of our third study (III) was to describe the long-term durability of surgical results in routine clinical practice, the impact of fibrin glue on the incidence of surgical failure, and the subjective outcomes ten years after the operation. We found that the health-related quality of life of the patient cohort was close to that of the Finnish general population. The patient satisfaction was high, but dissatisfaction with the treatment was associated with the decreased health-related quality of life. Flatulence and dysphagia were the most common side effects of the treatment, while dysphagia was the most common problem among the dissatisfied. Eighty-nine percent of the fundoplication wraps were intact, and only 6% of the patients were unsatisfied with the results. The subjective and objective long-term results were comparable to those published from more specialized centers. For the first time, it was noted that the use of fibrin glue seemed to decrease the incidence of defective fundoplication wraps in the long term. In our fourth (IV) article, we aimed to present almost lifelong follow-up (>30 years) after open Nissen fundoplication in terms of subjective outcomes and health-related quality of life and to describe the indications for antireflux surgery before the laparoscopic era. According to our results, a successful Nissen fundoplication may provide a lifelong control of reflux symptoms, and the health-related quality of life of the patients was comparable to that of the general population over 30 years after the operation. The indications for the procedure reflected the practices of the time, and, in most of the patients, GERD was objectively verified. The results of this thesis suggest that laparoscopic Nissen fundoplication can provide durable surgical results in routine clinical practice as well. In the case of successful surgery, fundoplication may give the patient a lifelong relief of reflux symptoms, but the potential risks and treatment-related side effects should be weighed cautiously when considering operative treatment. These results provide information for physicians and patients when weighing the benefits and harms of the treatment

Performance of thin Vivacit-E hip liners: no relevant wear during ex vivo testing at high acetabular inclination angle

Background and purpose: There is concern among clinicians regarding the performance of thin, highly cross-linked polyethylene acetabular liners at high inclination angles that cause edge contact and high contact stresses. We studied ex vivo wear performance of thin, vitamin-E grafted, highly cross-linked polyethylene (Vivacit-E) liners in relation to high acetabular inclination angle. Materials and methods: Wear of Vivacit-E acetabular liners (thickness 4.0–5.7 mm) was studied with a validated hip joint simulator at 2 different acetabular inclination angles, 40° (optimal) and 65° (high). The test simulated walking. Wear was evaluated gravimetrically and dimensionally. Results: At the optimal inclination angle, slight weight gain occurred. At the high angle, the liners lost weight slightly. Due to the minimal weight loss, gravimetric wear rates were difficult to determine. Linear wear was below the detection limit of 0.01 mm. Conclusion: Even with the high acetabular inclination angle, the prostheses performed well in the present test conditions. The wear rates of the liners were estimated to be clearly below the osteolysis threshold of 0.05 mm/year, below which osteolysis is absent. Since the present hip joint simulator has been shown to produce clinically relevant wear, these ex vivo results are likely to reflect the in vivo behavior of the design

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

Varying but reduced use of postoperative mobilization restrictions after primary total hip arthroplasty in Nordic countries: a questionnaire-based study

Background and purpose — Mobilization has traditionally been restricted following total hip arthroplasty (THA) in an attempt to reduce the risk of dislocation and muscle detachment. However, recent studies have questioned the effect and rationale underlying such restrictions. We investigated the use of postoperative restrictions and possible differences in mobilization protocols following primary THA in Denmark (DK), Finland (FIN), Norway (NO), and Sweden (SWE). Patients and methods — All hospitals performing primary THA in the participating countries were identified from the latest national THA registry report. A questionnaire containing questions regarding standard surgical procedure, use of restrictions, and postoperative mobilization protocol was distributed to all hospitals through national representatives for each arthroplasty registry. Results — 83% to 94% (n = 167) of the 199 hospitals performing THA in DK, FIN, NO, and SWE returned correctly filled out questionnaires. A posterolateral approach was used by 77% of the hospitals. 92% of the hospitals had a standardized mobilization protocol. 50%, 41%, 19%, and 38% of the hospitals in DK, FIN, NO, and SWE, respectively, did not have any postoperative restrictions. If utilized, restrictions were applied for a median of 6 weeks. Two-thirds of all hospitals have changed their mobilization protocol within the last 5 years—all but 2 to a less restrictive protocol. Interpretation — Use of postoperative restrictions following primary THA differs between the Nordic countries, with 19% to 50% allowing mobilization without any restrictions. There has been a strong tendency towards less restrictive mobilization over the last 5 years

Varying but reduced use of postoperative mobilization restrictions after primary total hip arthroplasty in Nordic countries: a questionnaire-based study

Background and purpose — Mobilization has traditionally been restricted following total hip arthroplasty (THA) in an attempt to reduce the risk of dislocation and muscle detachment. However, recent studies have questioned the effect and rationale underlying such restrictions. We investigated the use of postoperative restrictions and possible differences in mobilization protocols following primary THA in Denmark (DK), Finland (FIN), Norway (NO), and Sweden (SWE). Patients and methods — All hospitals performing primary THA in the participating countries were identified from the latest national THA registry report. A questionnaire containing questions regarding standard surgical procedure, use of restrictions, and postoperative mobilization protocol was distributed to all hospitals through national representatives for each arthroplasty registry. Results — 83% to 94% (n = 167) of the 199 hospitals performing THA in DK, FIN, NO, and SWE returned correctly filled out questionnaires. A posterolateral approach was used by 77% of the hospitals. 92% of the hospitals had a standardized mobilization protocol. 50%, 41%, 19%, and 38% of the hospitals in DK, FIN, NO, and SWE, respectively, did not have any postoperative restrictions. If utilized, restrictions were applied for a median of 6 weeks. Two-thirds of all hospitals have changed their mobilization protocol within the last 5 years—all but 2 to a less restrictive protocol. Interpretation — Use of postoperative restrictions following primary THA differs between the Nordic countries, with 19% to 50% allowing mobilization without any restrictions. There has been a strong tendency towards less restrictive mobilization over the last 5 years