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Introduction: Previous bone density studies have generally shown bone resorption around both cemented and uncemented total hip arthroplasty (THA) stems. This is presumed to be due to stress shielding. Short stems have been introduced partly to preserve bone in the proximal femur by a more physiological loading of the bone. The purpose of this study was to evaluate bone remodeling around a short, fully hydroxyapatite-coated titanium stem that comes in a collared and collarless version., Patients and Methods: A prospective cohort of 50 patients included in a study evaluating the Furlong Evolution stem has been followed for 5 years. Examination was done with dual energy X-ray absorptiometry (DXA) postoperatively, at 1, 2 and 5 years. Clinical outcome was followed with radiography and both general and hip specific outcome measures., Results: The two versions of the stem behaved similarly regarding bone remodeling. After an initial decrease up to 1 year, bone mineral density (BMD) increased in all Gruen zones up to 2 years and at 5 years bone stock was still preserved compared with postoperatively (net BMD + 1.2% (95% CI - 0.4 to 2.8)). Increase in BMD occurred mainly in the greater trochanter and distally around the stem with a decrease in the calcar area. Both versions showed excellent clinical outcome up to 5 years., Conclusion: This short stem seems to preserve proximal bone stock up to 5 years, exhibiting similar behaviour both with and without a collar., Trial Registration Number and Date of Registration: ClinicalTrials.gov, (identifier: NCT01894854). July 10, 2013., (© 2021. The Author(s).)

Background and purpose - Vitamin E infused highly cross-linked polyethylene (VEPE) was introduced in order to enhance oxidative resistance in highly cross-linked polyethylene cups in total hip arthroplasty (THA). We have, with a follow-up of 5 years, evaluated wear characteristics of 2 identically designed cemented cups with the only difference being the material, VEPE or ultra-high molecular weight polyethylene (UHMWPE). Furthermore, we report cup migration and clinical outcome. Patients and methods - 48 patients with primary osteoarthritis were randomized to either UHMWPE or VEPE cups. Patients were followed with radiostereometric analysis (RSA) from the first postoperative day, at 3 months, 1, 2, and 5 years as well as with hip-specific outcome questionnaires. Results - At 3 months the mean proximal head penetration for UHMWPE was 0.07 mm (95% CI 0.03-0.11) and for VEPE 0.06 mm (-0.01 to 0.13). Thereafter, there was a continuous annual wear of 0.08 mm/year, up to 0.46 mm (0.36-0.57) at 5 years, for the UHMWPE cup. The VEPE cup showed low annual wear of 0.01 mm/year, up to 0.09 mm (0.02-0.16) at 5 years. In the first 3 months the UHMWPE cup migrated cranially 0.08 mm (0.03-0.13) whereas the VEPE cup migrated 0.17 mm (0.10-0.24), Thereafter, they showed similar migration patterns with stabilization between 2 and 5 years up to 0.21 mm (0.04-0.39) and 0.24 mm (0.13-0.36) respectively. The HOOS remained good up to 5 years, and no cup was revised. Interpretation - Compared with otherwise identical UHMWPE cups the cemented VEPE cup shows statistically significant reduction of wear up to 5 years and both cup types stabilize well with good clinical outcome.

Background and purpose - Cup wear in total hip arthroplasty (THA) can be affected by different manufacturing processes of the polyethylene (PE). We report the long-term wear pattern differences, as well as early creep behavior, between conventional PE and highly cross-linked PE (HXLPE) liners, as measured with radiostereometry (RSA) up to 10 years. We also compare migration and clinical outcome of 2 similar uncemented cups with different backside surface roughness.Patients and methods - We included 45 patients with primary osteoarthritis. 23 received a conventional liner and 22 an HXLPE liner in a similar uncemented cup, but with a slightly rougher surface. The patients were followed up with RSA and hip-specific outcome questionnaire (HOOS) at 3 months, 1, 2, 5, and 10 years.Results - During the first 3 months both liners showed expected deformation with mean proximal head penetration of 0.39 mm (conventional PE) and 0.21 mm (HXLPE). Between 3 months and 10 years there was a difference in annual wear with 0.12 mm/year for the conventional liner and 0.02 mm/year for the HXLPE liner. The cup with rougher surface had less initial migration but both types had stabilized after 3 months. The HOOS scores improved after surgery and remained high for both groups throughout the study period.Interpretation - Up to 10 years the HXLPE has consistent lower annual wear, possibly contributing to longer survival of the THA, compared with conventional PE. All patients reported good results regardless of liner type.

Background: There is an increasing interest in shorter, proximally loading, uncemented femoral stems. The aim of this study was to evaluate a new short stem type, its design based on a well-proven precursor, but with several new design features to facilitate easier insertion and possible preservation of proximal bone stock. It is available with or without a collar., Methods: The study includes 50 patients with primary osteoarthritis, mean age 59 (range 36-75) years, randomised to receive either the collar-fitted or the collarless stem. The patients underwent repeated radiostereometry (RSA) examinations (0, 0.5, 3, 12, 24 months), conventional radiography and filled out both hip-specific (HOOS) and general health (EQ-5D) questionnaires., Results: There was no statistically significant difference between the collared and collarless stems regarding migration and clinical outcome. Both stem types exhibit a similar pattern of initial subsidence (collared 0.63 mm vs. collarless 0.75 mm [ p = 0.50]) and retroversion (collared 0.71° vs. collarless 0.97° [ p = 0.36]) up to 3 months followed by stabilisation, in similarity with its precursors, suggesting good osseointegration. No stem has been revised or considered loose., Conclusions: The new design features, including shortening the stem, do not compromise migration pattern or osseointegration, regardless collar or not.

Background and purpose - Modular-neck hip stems have been identified with corrosion-related problems from the neck-stem junction. We report an ongoing varus deformity of modular-neck hip stems with simultaneous metal ion release observed during a study comparing the migration of modular vs. standard hip stems.Patients and methods - We followed 50 patients with modular and 25 with standard neck stems using radiostereometry (RSA). At 5-year follow-up, we noted a compromised integrity of the modular stem with varus deformity in the neck-stem interface. Changes in head-tip distance as well as whole-blood ion concentration and MRI findings were analyzed. The modular stems were followed further up to 8 years.Results - The head-tip distance decreased continuously by 0.15 mm per year resulting in 1.2 (95% CI 1.0-1.4) mm at 8 years for modular stems, while for the standard stems at 5 years, the decrease was 0.09 (CI 0.0-0.2) mm or 0.02 mm/year. For the modular stems, the reduction in head-tip distance correlated to the increase in whole-blood cobalt concentration at 8 years but not to the MRI grading of tissue reactions. At 5 years, cobalt levels were 4.9 µg/L for modular stems and at 8 years 4.8 µg/L, whereas for standard stems this was 1.0 µg/L. After 8 years, 9 of 72 stems had been revised for different reasons, but only 1 with obvious adverse local tissue reaction (ALTR).Interpretation - We present a surprisingly large progressive deformation at the modular neck-stem junction, but so far without a definite clinical problem. Even the femoral head seems to show slight compression onto the taper over time. A high rate of revisions for the modular type of this stem has raised general concerns, and it has been recalled from the market.

Background: A common bearing combination in total hip arthroplasty today is a metal femoral head articulating with polyethylene in the cup. Ceramic heads are thought to be more resistant to third-body damage, and have better wettability and decreased surface roughness, which taken together have been suggested to result in less polyethylene wear. The purpose of this study is to compare the initial creep deformation and follow wear pattern, using radiostereometric analysis, of ceramic and metal femoral heads that articulate with a modern highly cross-linked polyethylene cup liner., Methods: Fifty patients with primary osteoarthritis and scheduled for an uncemented total hip arthroplasty were randomized 1:1 to either a ceramic (BIOLOX delta) or a metal (CoCr) femoral head. The patients were followed up for 5 years with repeated radiostereometric analysis examinations (postoperatively, then at 14 days, 3, 12, 24, and 60 months), as well as a hip-specific outcome questionnaire., Results: During the first 3 months both groups showed expected creep within the liner of 0.12 mm (standard deviation 0.03) for the ceramic and 0.08 mm (standard deviation 0.02) for the metal heads. Between 3 months and 5 years there was very little wear of the liner in either group, corresponding to 0.003 mm/y for ceramic and 0.007 mm/y for metal heads. There was no difference in cup migration or clinical outcome between the groups and no cups were revised., Conclusion: With the introduction of modern highly cross-linked polyethylene, the ceramic head demonstrates no superiority when it comes to either early deformation or polyethylene wear compared with the metal head., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Inferior placement of a femoral stem is predictive for early loosening and failure, but does restoration of the original hip anatomy benefit the function and survival of a total hip replacement?, Methods: Seventy-five patients with primary unilateral hip osteoarthritis operated with an uncemented anatomical stem were randomized for either standard or modular stems. We used 50 ABG II stems with modular necks and 25 standard stems (control group). We measured the symmetry in hip anatomy between healthy and operated side. The anatomical restoration variables were anteversion, global offset, and femoral offset/acetabular offset (FO/AO) quota. We performed measurements using a CT-based 3D templating and measuring software. Migratory behavior of the stems was then measured postoperatively with repeated radiostereometry (RSA) examinations over 5 years., Results: Both stem types showed an early (within 3 months) good stabilization after an initial slight rotation into retroversion and subsidence. There were no significant differences in RSA migration between modular and standard stems. Postoperative anteversion and FO/AO quota had no impact on stem migration. The standard stem tended to result in insufficient global offset (GO), whereas the modular stem did not., Conclusions: The modular stem gave good symmetrical anatomical restoration and, like the standard version, a benign migratory behavior. Anteversion, GO, and FO/AO quota had no significant impact on stem migration. It therefore seems to be of no importance whether we choose a modular or a standard stem with regard to postoperative stem migration for this stem type. We overestimated the effect anatomical parameters have on stem movement; hence, we believe the study to be underpowered., Trial Registration: ClinicalTrials.gov identifier: NCT01512550. Registered 19 January 2012-retrospectively registered.

Background and purpose - Fast-track care programs have been broadly introduced at Swedish hospitals in elective total hip and knee replacement (THR/TKR). We studied the influence of fast-track programs on patient-reported outcomes (PROs) 1 year after surgery, by exploring outcome measures registered in the Swedish arthroplasty registers.Patients and methods - Data were obtained from the Swedish Knee and Hip Arthroplasty Registers and included TKR and THR operations 2011-2015 on patients with osteoarthritis. Based on questionnaires concerning the clinical pathway and care programs at Swedish hospitals, the patients were divided in 2 groups depending on whether they had been operated in a fast-track program or not. PROs of the fast-track group were compared with not fast-track using regression analysis. EQ-5D, EQ VAS, Pain VAS, and Satisfaction VAS were analyzed for both THR and TKR operations. The PROMs for TKR also included KOOS.Results - The differences of EQ-5D, EQ VAS, Pain VAS, and Satisfaction VAS 1 year after surgery were small but all in favor of fast-track for both THR and TKR, also in subscales of KOOS for TKR except KOOS QoL. However, the effect sizes as measured by Cohens' d formula were < 0.2 for all PROs, in both THR and TKR.Interpretation - Our results indicate that the fast-track programs may be at least as good as conventional care from the perspective of PROs 1-year postoperatively.

Background:: Bisphosphonates have previously been shown to increase the density of impacted graft bone. In the present study we hypothesise that bisphosphonates also reduce early stem subsidence. We examined the effect of locally applied bisphosphonate to allografts on prosthetic micromotion and bone density in femoral stem revision with impaction grafting., Methods:: 37 patients were randomised to either clodronate or saline as local adjunct to the morsellised allograft bone. 24 patients were finally analysed per protocol and evaluated by dual-energy x-ray absorptiometry (DXA) during the first year and with radiostereometric analysis (RSA) for 5 years., Results:: There were no significant differences neither in bone density, nor in migratory behaviour between the groups. The femoral stems had subsided 3.6 mm in both groups (p = 0.99) at 5 years and there was no difference as measured over time with mixed models analysis. The clinical outcome was good in both groups., Conclusion:: Clodronate as a local addendum to allograft bone in hip revision did not increase bone density or reduce micromotion of the implant.

Background and purpose - Fast-track care programs in elective total hip and knee replacement (THR/TKR) have been introduced in several countries during the last decade resulting in a significant reduction of hospital stay without any rise in readmissions or early adverse events (AE). We evaluated the risk of readmissions and AE within 30 and 90 days after surgery when a fast-track program was introduced in routine care of joint replacement at 8 Swedish hospitals. Patients and methods - Fast-track care programs were introduced at 8 public hospitals in Västra Götaland region from 2012 to 2014. We obtained data from the Swedish Hip and Knee Arthroplasty Registers for patients operated with THR and TKR in 2011-2015. All readmissions and new contacts with the health care system within 3 months with a possible connection to the surgical intervention were requested from the regional patient register. We compared patients operated before and after the introduction of the fast-track program. Results - Implementation of the fast-track program resulted in a decrease in median hospital length of stay (LOS) from 5 to 3 days in both THR and TKR. The total readmission rate <90 days for THR was 7.2% with fast-track compared with 6.7% in the previous program, and for TKR 8.4% in both groups. Almost half of the readmissions occurred without any AE identified. There was no statistically significant difference concerning readmissions or AE when comparing the programs. Interpretation - Implementation of a fast-track care program in routine care of elective hip and knee replacement is effective in reducing hospital stay without increasing the risk of readmissions or adverse events within 90 days after surgery.

Background: Porous metal augments have been used successfully for management of large acetabular defects during revision hip arthroplasty. The purpose of this study was to retrospectively review and compare the clinical and radiographic outcomes of porous metal augments in cemented and uncemented acetabular revisions, all performed at the same institution., Methods: Using our institutional clinical databases, the clinical and radiological outcomes of 104 cemented and 43 uncemented acetabular revisions with metal augments, performed between 2006 and 2015, were studied and compared. Acetabular augments were used when preoperative and intraoperative findings indicated the presence of large acetabular defects that can hinder the stability of the revision implants., Results: At a mean follow-up of 60.1 months (range 12.7-112.1), a total of 5 cups (3.4%), being 3 cemented (2.8%) and 2 uncemented (4.6%), had shown signs of aseptic loosening with cup and augment migration and 4 of these have been re-revised (2.7%). At final follow-up, the European Quality of Life-5 Dimensions for generic health, and the Hip disability and Osteoarthritis Outcome Score (HOOS) parameters had improved substantially without any significant difference between fixation techniques., Conclusion: Porous metal augments show comparable excellent radiographic and clinical mid-term outcomes when combined with cemented or uncemented cups in revision hip arthroplasty., (Copyright © 2016 Elsevier Inc. All rights reserved.)

In 1999, we reported on the 2-year results of a series of 21 first-time socket revisions using impacted morselized allograft bone. Seven still migrated between 1.5 and 2 years. Seventeen remained for the current 5-year follow-up. No socket had been rerevised. Five sockets showed signs of radiographic loosening. These 5 cases also exhibited radiographic signs of allograft resorption as well as high rates of socket migration and rotation as measured by radiostereometric analysis. Of the 6 remaining sockets that had migrated between 1.5 and 2 years, 3 stabilized and 3 were among those with signs of radiographic loosening. Fifteen patients (15 hips) revealed pain reduction at the 5-year follow-up. Three had slight pain on walking that disappeared immediately at rest (pain score 4). All the others revealed either no pain (pain score 6) or slight pain that disappeared with activity (pain score 5). No pattern of early socket migration according to radiostereometric analysis could be identified, predicting later socket migration or loosening. The rate of cases with signs of radiographic loosening (29%, 5/17) was comparable to that reported by the Nijmegen group but the follow-up was shorter in the current study. The rate of cases with signs of radiographic loosening was comparable to both conventionally cemented socket revisions and cementless revisions. The future will show if further sockets loosen and if the loose sockets up to date will end up in rerevisions.

We used roentgen stereophotogrammetric analysis to follow 33 C-stem femoral components for two years after primary total hip arthroplasty. All components migrated distally and posteriorly within the cement mantle. The mean distal migration was 1.35 mm (sd 0.62) at two years and the mean posterior migration was 1.35 mm (sd 0.69) at two years. All the femoral components rotated into retroversion with a mean rotation at two years of 1.9 degrees (sd 1.1). For all other directions, the prosthesis was stable up to two years. Compared with other tapered prostheses, the distal migration of the C-stem is the same, but posterior rotation and posterior migration are greater.

Background: There have been few studies evaluating patient-reported quality of life outcomes after hip revision with impaction bone grafting., Patients and Methods: The inclusion criteria were aseptic loosening after primary arthroplasty performed for osteoarthrosis, and first-time revision with impacted morselized allograft bone and cemented Exeter stem. During a 4-year period, 35 patients were eligible and all were included. The Nottingham Health Profile (NHP) was completed by the patients and the Charnley hip scores recorded by the examining surgeon preoperatively, after 6 months and yearly up to 4 years (28 patients) postoperatively. For comparison, 35 osteoarthrotic patients completed the NHP 4 years after cemented Exeter primary arthroplasty., Results: At 4 years, the NHP scores for the revision patients did not differ significantly from those recorded in the primary arthroplasty group. Among the revision patients, mixed model analysis showed improvement in NHP pain (p < 0.001) and physical mobility scores (p = 0.002). The effect size at 4 years was large for pain (1.2) and moderate for physical mobility (0.6). The major improvement was recorded at 6 months, with no further substantial change observed. The correlations between the NHP and Charnley scores were weak or moderate (r, -0.15 to -0.67)., Interpretation: Hip revision with impaction bone grafting leads to substantially improved quality of life, similar to that 4 years after primary arthroplasty.

Background: The use of impacted morselized allograft bone and cement in hip revision arthroplasty has been popular, but studies that specifically address intraoperative and postoperative complications have been scarce., Methods: All complications that occurred during, and within the first year after, 144 consecutive hip revision arthroplasties (108 stems and 130 sockets) performed with impacted morselized allograft bone and cement were recorded. Clinical and radiographic follow-up evaluation was performed at three months and at one year after surgery for all patients except eight (seven who had died of causes unrelated to the hip surgery and one who had sustained a stroke). Of these eight patients, seven had a six-week and/or three-month follow-up evaluation., Results: Thirty-nine femoral fractures occurred in thirty-seven hips; twenty-nine of the fractures occurred during surgery and ten, within five months after surgery. Of the intraoperative femoral fractures, twelve were proximal, nine were diaphyseal, and eight involved the greater trochanter. Of the postoperative femoral fractures, one was proximal and nine were diaphyseal. Other intraoperative complications were the creation of a femoral cortical window in seven hips and incidental perforation of the femoral cortex in fourteen. Multivariate analysis showed the risk factors for femoral fracture during or after revision to be concomitant disease, greater deficiency of the femoral bone stock, and an intraoperative femoral window or perforation. Other complications included dislocation of the femoral head in nine hips, deep infection in one hip, persistence of preoperative deep infection in one hip, and superficial wound infection requiring wound débridement in two hips., Conclusions: We found the complication rate to be high after hip revision arthroplasty performed with impacted morselized allograft bone and cement. The most serious complication was postoperative diaphyseal femoral fracture.

The Exeter stem and impacted, morselized allograft bone and cement were used in the revisions of 18 consecutive femoral components (17 patients). The primary arthroplasty had been done because of osteoarthritis. All of the femoral components were revised for the first time because of aseptic loosening. The migration pattern of the Exeter stem after revision was studied using roentgen stereophotogrammetric analysis. At 2 years after surgery, all 18 femoral stems had migrated in the distal direction (average, 2.5 mm). In addition, seven of the stems had migrated in the medial direction (average, 1.3 mm), and two stems had migrated in the lateral direction (0.5 mm and 1 mm, respectively). Sixteen of the femoral stems also had migrated in the posterior direction (average, 2.9 mm), but none migrated in the anterior direction. The migration rate decreased gradually with time during the followup. Six femoral stems continued to migrate between 1.5 and 2 years after surgery. In patients with major femoral bone deficiency at the time of hip revision, the use of impacted morselized allograft bone and cement yielded an initial fixation similar to that obtained in conventionally cemented revisions. Pain had improved in all patients at the 2-year followup.

We revised the hip (6 stems and 5 sockets) with impacted morselized allografts and cement in 6 patients. We followed prosthetic migration by roentgen radiostereometric analysis (RSA) every 7th day for 6 weeks after the first (index) examination performed on the first postoperative day before mobilization. Most of the migration occurred during the first 2 weeks. In most cases more than half of the distal stem migration was seen between the 1st and 14th days. In all cases, the stem and socket migrations slowed down gradually and several prosthetic components had become stable after 5 weeks. We conclude that it is essential to perform the index RSA examination on the 1st or 2nd day after surgery and to state when and how weight bearing should be permitted. Otherwise it will be difficult to compare prosthetic migration in various studies and define normative values for migration predicting survival.

In a consecutive series of hip revisions due to mechanical loosening, using impacted morselized allografts and cement, we followed 21 acetabular components by radiostereometric analysis (RSA) during 2 years. All but 1 acetabular component migrated in the proximal direction (median 2.1 (0.5-6.4) mm). 6 components migrated in the medial direction (median 0.8 (0.4-1.2) mm) and 6 in the lateral (median 0.8 (0.4-2.0) mm). 14 components migrated in the posterior direction (median 0.8 (0.3-2.3) mm) and 1 in the anterior 0.6 mm. The migration rate gradually decreased in all directions, but 7 acetabular components still migrated in at least 1 direction (median 0.3-0.6 mm) between 1.5 and 2 years postoperatively.

We followed 23 patients from the primary total hip arthroplasty to revision for a bacteriologically proven deep infection with a low virulent organism. The median time to revision was 14 (4-65) months. During this period, the maximum ESR value was median 50 (22-110) mm and the maximum CRP value was 35 (9-95) mg/L. 25 of the 98 CRP values recorded were normal (< 9 mg/L) and 22/89 ESR values were below 30 mm/h. In 6 patients, all CRP values were below 20 mg/L, but 5 of these patients had an ESR > 30 mm. Before the revision, normal values for both tests were found in only 1 patient. Both normal values and slight-to-moderate increases in ESR and/or CRP are consistent with a low-grade periprosthetic hip infection. We recommend that ESR should be determined preoperatively in all patients scheduled for total hip replacement to establish a baseline.