Session 14: Hip II

Karen Dyreborg, Gunnar Flivik, Mikkel Rathsach Andersen, Nikolaj Winther, Søren Solgaard, Michael Mørk Petersen
Departments of Orthopaedic Surgery, Rigshospitalet and Gentofte Hospital; Department of Orthopaedic Surgery, Skåne University Hospital in Lund; Department of Orthopaedic Surgery, Rigshospitalet; Department of Orthopaedic Surgery, Rigshospitalet; Department of Orthopaedic Surgery, Gentofte Hospital; Department of Orthopaedic Surgery, Rigshospitalet


Background: Generally, the primary total hip arthroplasty (THA) is a successful procedure with good clinical outcome. New implants are continuously developed, enhancing what is and has been, taking advantage of current knowledge and technology. One of these technologies is Radiosteriometric Analysis (RSA) which is used to predict implants at risk of later aseptic loosening. As the population grows older, an increasing number of people will be having THA done at some point in their life. In the period 1995-2011 a total of 17,791 THA revisions were performed in Denmark alone (5.8 mio. inhabitants).
Purpose / Aim of Study: The Bi-Metric THA stem had been developed into the Echo Bi-Metric THA stem and we wanted to know: how did they compare with regards to the migration patterns measured by RSA?
Materials and Methods: In the period February 2015 to September 2017 we enrolled and randomized 62 patients (mean age=64(49-74) years, F/M=28/34) who were planned for an uncemented THA at Herlev Gentofte Hospital (the Gentofte department) to receive either an Echo Bi-Metric® Full Proximal Profile THA stem or a Bi-Metric® Porous Primary THA stem from Zimmer Biomet. We performed radiosteriometric analysis (RSA) with model-based technique postoperatively, at 3, 6 and 12 months with measurement of rotation around and translation down all three axes (x, y, and z). Statistics: Mann-Whitney U test.
Findings / Results: Before 3 months follow-up two patients were reoperated (one due to periprosthetic fracture, one stem did not fit well and rotated in the femur). We found the early migration (mean) at 3, 6 and 12 months with regards to subsidence (i.e. y-translation) to be -1,13mm, -0,96mm and -1,03mm for the BiMetric and -1,51mm, -1,47mm and -1,44mm for the Echo BiMetric (p-value at 3, 6 and 13 months = 0.53; 0.33; 0.98). Measuring anteversion and retroversion (i.e. y-rotation) we found a mean rotation at 3, 6 and 12 months to be 2.11, 2.17 and 1.91 degrees for the BiMetric and 1.71, 2.15 and 2.01 degrees for the Echo BiMetric (p-value at 3, 6 and 13 months = 0.55; 0.63; 0.97).
Conclusions: Both stems showed stabilization at 3 months leading to the conclusion that we consider both of them to be performing well with regards to the early micromotion.

Pelle Baggesgaard Petersen, Christoffer Calov Jørgensen, Henrik Kehlet
Section for Surgical Pathophysiology, Rigshospitalet; Section for Surgical Pathophysiology, Rigshospitalet; Section for Surgical Pathophysiology, Rigshospitalet


Background: Venous thromboembolism (VTE) is a serious complication to total hip and knee arthroplasty (THA/TKA). However, recent publications found low 90-days incidences of VTE with in-hospital only thromboprophylaxis after fast-track THA and TKA, but with a subgroup with VTE despite thromboprophylaxis
Purpose / Aim of Study: To provide a detailed investigation on the incidence and risk of VTE despite ongoing thromboprophylaxis after fast-track THA and TKA.
Materials and Methods: We used a prospective multicenter cohort from Jan 2010–Aug 2017. Prospective collection of preoperative comorbidity and demographics from the Lundbeck Foundation Centre for Fast-track Hip and Knee replacement database (www.FTHK.dk). Length of stay (LOS) and complete 90-days follow- up was obtained from the Danish National Patient Registry and review of medical records. Patients with preoperative use of potent anticoagulants were excluded.
Findings / Results: Of 34,397 procedures 32 (0.09%, 22.4% of all VTE) patients had VTE despite ongoing thromboprophylaxis. Median time to VTE was 2 days [IQR; 2-4]. 29 (2.1%) occurred in patients with LOS > 5 days and 3 during primary admission but with LOS ≤ 5 days. 78% of VTE’s occurred without any identifiable pre-VTE complication. Risk-factor analysis found age 81-85 years OR 6.3 (95% CI; 1.8-22.4, p =0.005), BMI < 18.5 OR 11.1 (1.1-109.2, p=0.040), BMI 35-40 OR 5.1 (1.0-26.2, p=0.050) and BMI ≥ 40 OR 21.8 (4.6-103.6, p<0.001) as statistically significant.
Conclusions: VTE after fast-track THA/TKA occurred in 0.09% (22% of all VTE) despite ongoing thromboprophylaxis. Further investigation of this “high risk” population might help to improve the optimal choice for patient-specific thromboprophylaxis to further reduce incidence of postoperative VTE.

Pelle Baggesgaard Petersen, Henrik Kehlet, Christoffer Calov Jørgensen
Section for Surgical Pathophysiology, Rigshospitalet; Section for Surgical Pathophysiology, Rigshospitalet; Section for Surgical Pathophysiology, Rigshospitalet


Background: Implementation of “enhanced recovery” or “fast- track” protocols has improved perioperative surgical care leading to a reduction in length of hospital stay (LOS) and postoperative complications within a variety of surgical procedures including total hip (THA) and knee arthroplasty (TKA). However, the effects of a continuous use and refinement of enhanced recovery protocols on postoperative morbidity and LOS have not been evaluated.
Purpose / Aim of Study: To investigate time-related changes in LOS, risk of LOS > 4 days, readmissions and mortality after fast- track THA and TKA within a prospective multicenter collaboration focusing on the continuous refinement of perioperative care.
Materials and Methods: Prospective multicentre cohort study in fast-track THA and TKA from Jan 2010 to Aug 2017 from 9 high-volume orthopaedic centres with established fast-track protocols (www.FTHK.dk). Prospective collection of comorbidities and complete 90-day follow-up from The Danish National Patient Registry and medical records. Primary outcomes were time- related changes in LOS, fraction of procedures with a LOS >4 days, 30-, and 90-days readmissions. Secondary outcomes were analyses of specific types of morbidity and 90-days mortality.
Findings / Results: Of 36,935 included procedures median age was 69 [IQR: 62-75] years and 58% women. LOS was median 3 [2–3] days in 2010 declining to 1 [1-2] days in 2017. The fraction with LOS > 4 days declined from 9.7% to 4.6% due to a decline in both “medical” complications (4.4% to 2.7%), “surgical” complications (1.5% to 0.6%), and no recorded morbidity (3.8% to 1.3%). 30- and 90-days readmission rates declined from 6.1% and 8.6% in 2010 to 5.3% and 7.7% in 2017, respectively. There was a slight increase in “surgical” complications leading to readmission ≤ 90 days from 2.9% to 3.8%, mainly due to more wound complications. All- cause 90-days mortality was unchanged at 0.3%.
Conclusions: Within a multicenter collaboration focusing on further refinements of similar well-established fast-track protocols for THA and TKA, there was a continued reduction of LOS and morbidity within a 7 year time- period

Louise Ujunma Kiesbye Holm, Mogens Laursen
Klinisk Institut, Aalborg Universitet, Ortopædkirurgisk Forskningsenhed, Aalborg Universitetshospital. Ortopædkirurgisk Afdeling, Aalborg Universitetshospital, Klinik Farsø; Klinisk Institut, Aalborg Universitet, Ortopædkirurgisk Forskningsenhed, Aalborg Universitetshospital. Ortopædkirurgisk Afdeling, Aalborg Universitetshospital, Klinik Farsø


Background: Templating is considered a very important part of preoperative planning for a Total Hip Arthroplasty (THA). Besides discovering needs for very small or large components, which could affect department logistics, templating also provides the possibility of better treatment. Restoration of the anatomical femoral off-set (FOS), has proved important for the recovery of function, abductor strength and quality of life.
Purpose / Aim of Study: This study seeks to investigate whether patients show greater improvement (measured by OHS and EQ5D-3L) if the planned off-set is achieved, compared to patients, whose planned off-set isn’t obtained.
Materials and Methods: The global femoral off-set was measured in pre- and post-surgery x-rays and compared to the patients’ OHS and EQ5D-3L before surgery, 6 and 12 months post-surgery. The planned stem Off-Set was also compared to the used. The sample (141) was split into two sub-samples: Plan fulfilled (66) & Plan not-fulfilled (75). The margin for fulfilment of the plan was a post-surgery FOS within 10 mm of the templated plan. SPSS was used to investigate the descriptive statistics and run two-sample t-tests.
Findings / Results: The ÄOHS-mean 0-6 months & 0-12 months for the Plan fulfilled-group were respectively 43,0 & 45,1; while the ÄOHS-mean 0-6 months & 0-12 months for the Plan not-fulfilled-group were 34,7 & 41,0. The ÄEQ-5D-3L- mean 0-6 months & 0-12 months for the Plan fulfilled group were 0,27 & 0,34; while the ÄEQ-5D-3L-mean 0-6 months & 0-12 months for the Plan not- fulfilled-group were 0,21 & 0,23. In spite of this, the t-tests did not show statistical significance, except for the Plan not-fulfilled-group’s mean in ÄEQ- 5D-3L 0-12 months. Therefore, no correlation could be proven; probably due to the small sample size.
Conclusions: The results of the descriptive statistics and two-sample t-tests showed a clear tendency towards the Plan fulfilled- group having a better recovery of function and quality of life after 6 and 12 months than the Plan not-fulfilled group. However, this must be investigated with a bigger sample size for a general conclusion to be made.

Claus Varnum, Geir Hallan, Anne Marie Fenstad, Ola Rolfson, Maziar Mohaddes, Keijo Mäkelä, Antti Eskelinen, Søren Overgaard
Department of Orthopaedic Surgery, Vejle Hospital; The Norwegian Arthroplasty Register, Department of Orthopedic Surgery, Haukeland University Hospital, Bergen, Norway; The Norwegian Arthroplasty Register, Department of Orthopedic Surgery, Haukeland University Hospital, Bergen, Norway; Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sweden; Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sweden; Department of Orthopaedics and Traumatology, Turku University Hospital, Turku, Finland; , Coxa Hospital of Joint Replacement, Tampere, Finland; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital


Background: The numbers of primary total hip arthroplasty (THA) have been increasing during recent years, but no detailed analysis on trends of the numbers of THA in patients younger than 50 years exists. This is important for evaluation of change in practice.
Purpose / Aim of Study: We aimed to investigate time trends in rates of gender, age, and diagnosis of primary THA in patients between 20-49 years in a population-based study from the Nordic Arthroplasty Registry Association (NARA).
Materials and Methods: From the NARA database we identified all primary THAs operated from January 1, 1995 to December 31, 2016 in patients aged 20-49 years (n=41,861). 5 time periods were defined: 1995-1999 (Period 1), 2000-2004 (Period 2), 2005-2009 (Period 3), 2010-2014 (Period 4), and 2015- 2016 (Period 5). These periods were used to describe time trends for gender, age and diagnoses. Proportions of total numbers within a given time period were calculated.
Findings / Results: 7,051 THAs (17%) were implanted in Period 1; 8,039 (19%) in Period 2; 10,343 (25%) in Period 3; 11,534 (27%) in Period 4; and 4,894 (12%) in Period 5, which was only 2 years. Gender: The proportion of males increased from 47% in Period 1, to 50% in Period 2, and 54-55% in Periods 3-5. Age: For the age groups 20-29 years and 30-39 years, the proportion of patients within each time period decreased throughout Periods 1-5 from 7% to 6% and 22% to 15%, respectively. However, patients aged 40-49 years increased from 71% in Period 1 to 79% in Period 5. The trends for age were similar for both men and women. Diagnosis: The proportion of OA was increasing throughout the Periods from 22% in Period 1 to 56% in Period 5. In contrast, the proportion of inflammatory disorders was decreasing from 17% in Period 1 to 3% in Period 5. Other diagnosis groups remained approximately constant throughout the different Periods.
Conclusions: We found an increasing numbers of patients aged between 20-49 years receiving a THA, especially for patients between 40 and 49 years. We do not believe that this increase is explained by increase in OA incidence but rather by change in practice. The study is important for the discussion on change in practice and the best treatment of the younger age groups in the future.

Niels Frederik Breum Jakobsen, Steffan Tabori-Jensen, Maiken Stilling, Torben Bæk Hansen
University Clinic for Hand, Hip and Knee Surgery, Regional Hospital West, Holstebro, Denmark; Department of Orthopedic Surgery, Aarhus University Hospital; Department of Orthopedic Surgery, Aarhus University Hospital; University Clinic for Hand, Hip and Knee Surgery, Regional Hospital West, Holstebro, Denmark


Background: Traditionally, outcomes following total hip arthroplasty(THA) in terms of Harris Hip Score (HHS) have been assessed by the surgeon. However, for an unbiased evaluation of effect after surgical interventions self-reported patient data are important. In patients treated for hip osteoarthritis with a THA, the HHS has excellent correlation between patient-self-reported data and surgeon-assessed data. It is unknown if these results are applicable to other patient groups receiving THA.
Purpose / Aim of Study: To investigate the correlation of patient-self-reported data compared with surgeon-assessed data in femoral neck fracture (FNF) patients treated with THA.
Materials and Methods: In a prospective cohort follow-up study we evaluated 124 FNF patients operated with dual mobility THA. At mean follow-up of 2.8 (range 1.0–7.7) years after surgery, participants were asked to complete a patient self-reported HHS (PR-HHS). On the same day surgeon completed the standard HHS too (surgeon-assessed HHS (SA-HHS). 8 participants missed completion of either the SA-HHS or the PR-HHS. The PR-HHS was rescaled to 100 for comparison of results (Mahomed et al, 2001). We tested differences between groups using a paired t-test. Correlation was assessed by Pearson’s correlation coefficient. Categorical variables were tested using Kappa’s coefficient.
Findings / Results: Patient age at the time of surgery was mean 74.8 (range 30–92) years.The rescaled mean PR-HHS value was 74.3 (SD 18.6) and significantly different from the mean SA-HHS value of 79.9 (SD 15.4), (p<0.001). The correlation between PR-HHS and SA-HHS was statistically significant and strong rp = 0.74 (p>0.001). The Kappa coefficient for HHS sub- variables indicated fair to moderate agreement: Pain (0.41), Support(0.67), Limp(0.37), Distance Walked(0.45), Stair Climbing(0.34), Shoes and Socks(0.55), and Sitting(0.28).
Conclusions: We found a strong correlation and a fair to moderate agreement between PR-HHS and SA-HHS at a minimum 1 year after THA in FNF patients, which is poorer than reported for patients treated with for hip osteoarthritis. Further studies are needed to explore the correlations between patient reported function and objective measures of e.g. walking distance in this patient group.

Galea Vincent, Ingelsrud Lina, Florissi Isabella, Shin David, Bragdon Charles, Malchau Henrik, Gromov Kirill, Troelsen Anders
Department of Orthopedic Surgery, Massachusetts General Hospital; Department of Orthopedic Surgery, Copenhagen University Hospital; Department of Orthopedic Surgery, Massachusetts General Hospital; Department of Orthopedic Surgery, Massachusetts General Hospital; Department of Orthopedic Surgery, Massachusetts General Hospital; Department of Orthopedic Surgery, Massachusetts General Hospital; Department of Orthopedic Surgery, Copenhagen University Hospital; Department of Orthopedic Surgery, Copenhagen University Hospital


Background: Patient-reported outcome measures (PROMs) evaluate symptoms following total hip arthroplasty (THA). A previous study suggested that one PROM, the Forgotten Joint Score (FJS), may better differentiate outcomes of patients performing well following surgery, compared to the Oxford Hip Score (OHS). The patient acceptable symptom state (PASS) is the threshold on a PROM that reflects a satisfactory symptom state.
Purpose / Aim of Study: This study aimed to define PASS values for the OHS and FJS at 3 months, 1 year, and 2 years after primary THA.
Materials and Methods: Patients undergoing primary THA from an academic medical center’s registry completed the OHS, FJS, and a satisfaction anchor question at 3 months (N=230, mean age 68, 61% female), 1 year (N=180, mean age 68, 62% female), or 2 years (N=187, mean age 67, 63% female) after surgery. Spearman’s correlation coefficients (rho) were determined between the OHS and FJS and the anchor question. PASS thresholds were derived with Received Operating Characteristics analyses with the 80% specificity rule, and 95% confidence intervals were calculated using 1000 non- parametric bootstrap replications.
Findings / Results: OHS (p<0.001) and FJS (p<0.001) values as well as the proportion of patients reporting a satisfactory state (p=0.002) increased between 3 months and 1 year. No such differences were observed between the 1- and 2-year cohorts (p>0.529). Spearman’s rho between the PROMs and the transition item were 0.47, 0.50, and 0.45 for the OHS, and 0.51, 0.53, and 0.56 for the FJS at 3-month, 1-year, and 2-year, respectively. At 3 months, 1 year, and 2 years, PASS thresholds (95% CI) were 33.5 (30.8-36.0), 39.5 (35.9-43.5), and 38.5 (34.5-42.0) for the OHS and 59.2 (54.3- 63.7), 67.7 (61.2-74.9), and 69.1 (61.9-75.4) for the FJS, respectively. From 3 months to 1 year, PASS thresholds for both the OHS and FJS increased significantly (p<0.005). Between 1 and 2 years, no significant change in PASS threshold was observed (p>0.223).
Conclusions: OHS and FJS PASS thresholds increased between 3-month and 1-year intervals, but not between 1- and 2-year intervals. These values will help interpret PROMs following THA, serving as clinically significant benchmarks and as patient-centered outcomes for research.

Hansen Sebrina, Mikkelsen Lone Ramer, Overgaard Søren , Mechlenburg Inger
Department of Orthopaedic Surgery, Orthopaedic Research Unit, Aarhus University Hospital; Elective Surgery Centre and Department of Clinical Medicine, Silkeborg Regional Hospital and Aarhus University; Orthopaedic research unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Department of Clinical Research, University of Southern Denmark; Department of Orthopaedic Surgery, Orthopaedic Research Unit and Department of Public Health and Department of Clinical Medicine, Aarhus University Hospital and Aarhus University


Background: The effectiveness of supervised progressive resistance training among patients with hip osteoarthritis is only scarcely investigated.
Purpose / Aim of Study: To estimate the effectiveness of supervised resistance training compared to usual treatment (without resistance training), for people with hip osteoarthritis at end of treatment on patient-reported function, pain, health-related quality of life, performance-based function, and on patient- reported function at 6-12 months.
Materials and Methods: Systematic review and meta-analysis. A systematic search was performed 16th January 2019 in eight electronic databases (Medline, Embase, Cochrane, Pedro, AMED, Scopus, SPORTDiscus and Cinahl) and other resources. The methodology of the included studies and the overall quality of evidence was assessed by two authors independently using the Cochrane Risk of Bias tool and the Grading of Recommendations Assessment, Development and Evaluation.
Findings / Results: Three studies were included with a total of 189 participants. A significant difference in favour of the supervised progressive resistance groups was found in patient-reported function (SMD 0.55 [95% CI 0.26 to 0.84]), hip-related pain (weighted MD 8.16 [95% CI 3.19 to 13.12]) and health-related quality of life (weighted MD 6.80 [95% CI 1.96 to 11.63]) at end of treatment. The overall quality of evidence was downgraded to low due to lack of blinding in the included studies and imprecision in one study due to low number of participants.
Conclusions: Supervised progressive resistance training is effective in improving patient-reported function, hip- related pain and health-related quality of life for patients with hip osteoarthritis compared to usual treatment (without resistance training). The level of evidence is low and thus future studies may change the results.

Marie Bagger Bohn, Bent Lund , Jeppe Lange
Ortopædien, Regionshospitalet Horsens; Ortopædien, Regionshospitalet Horsens; Ortopædien, Regionshospitalet Horsens


Background: Awareness of Gluteus medius (GM) and/or minimus tendon tears as the cause of lateral hip pain has been growing over the past two decades. It is estimated that Gluteus medius tears may may be present in as many as 25% of late late middle-aged women and 10% of middle middle-aged men. Tears that impart significant significant functional impairment to patients and may be a source of debilitating debilitating and chronic lateral hip pain. Unfortunately Unfortunately, these tears are often misdiagnosed misdiagnosed and, thus, treated insufficiently insufficiently.
Purpose / Aim of Study: To report 1-Year outcomes of our initial 12 cases of open surgical repair of Gluteus medius tears.
Materials and Methods: Data were prospectively collected between between September 2017 and June 2019. Inclusion criteria for the study were were patients undergoing open GM repair repair who had completed a one-year follow follow-up. MRI was used to visualize the GM tears. Assessment of the patients was done pre-operatively (baseline) and at 1 year follow-up. At these these time points, pain at rest, during activity activity and worst pain was recorded, a 30 sec sit to stand test (STT) and patient reported outcome measures (Copenhagen hip and groin score (HAGOS) and Oxford Hip score (OHS)) were completed.
Findings / Results: The cohort included 12 patients (11 women women) with a mean age of 53 years (range 16-71). From baseline to one-year year follow-up, pain at rest, during activity activity and worst pain (expressed as NRS) decreased from 2.1 to 0.7 (p=0.15), 6.3 to 3.6 (p=0.04) and 8.8 to 6.4 (p=0.04), respectively. The 30 sec SST improved from 11.5 to 14.8 (p=0.06). All HAGOS sub scores and OHS improved significantly (HAGOS; pain pain: 33 to 65 (p=0.001), Symptom: 43 to 74 (p>0.001), ADL: 34 to 64 (p=0.009), Sport/Rec: 30 to 56 (p=0.04), PA: 15 to 37 (p=0.04), QOL: 22 to 46 (p=0.003), and OHS; 24 to 35 (p=0.001)) from baseline to one year follow follow-up.
Conclusions: This study indicates that surgical repair may may be an effective treatment of MR verified verified gluteus medius tears. At one-year year follow-up the patients experience less less pain, subjective outcome measures improve and the 30 sec sit to stand test implies a functional gain.

Pelle Baggesgaard Petersen, Christoffer Calov Jørgensen, Henrik Kehlet
Section for Surgical Pathophysiology, Rigshospitalet; Section for Surgical Pathophysiology, Rigshospitalet; Section for Surgical Pathophysiology, Rigshospitalet


Background: Fast-track protocols in total hip and knee arthroplasty (THA/TKA) have improved postoperative recovery and reduced postoperative morbidity. Additionally, increasing life expectancy and improved surgical techniques have led to an increasing number of elderly patients undergoing THA and TKA. However, detailed studies on fast- track THA and TKA in the elderly are limited.
Purpose / Aim of Study: To describe length of stay (LOS) and postoperative morbidity in patients ≥ 85 years within a continuous multicenter fast-track collaboration.
Materials and Methods: We used a prospective observational cohort design with unselected consecutive data between 2010– 2017 on primary elective THA and TKA patients ≥ 85 years. Data were obtained from 9 centers reporting to the Lundbeck Foundation Centre for Fast-track Hip and Knee Replacement database (www.FTHK.dk) and the Danish National Patient Registry on LOS, readmissions, and mortality. Cause of morbidity were determined by review of health records.
Findings / Results: We included 1427 (3.9% of all THA/TKA) procedures with 62.3% THA. Median age was 87 (IQR: 85-88) years with 71% women. LOS decreased from median 4 (3-6) days in 2010 to 2 (2- 3) days in 2017. The proportion with LOS > 4 days decreased from 32 % to 18%, with a decrease in both combined “surgical”, “medical”, and no recorded morbidity leading to LOS > 4 days. No single specific organ dysfunction dominated the overall improvement. Readmission and mortality rates remained at about 11.7% and 0.9% at 30 days and 18.0% and 1.5% at 90 days, respectively. However, with a tendency towards a slight increase in “surgical” morbidity leading to readmissions ≤ 90 days.
Conclusions: This, detailed large multicenter fast-track THA/TKA study in patients ≥ 85 years found major improvements in LOS and patients with LOS > 4 days without increase in readmission or mortality rates. The unchanged readmission rate poses an area for further improvements.