Subsidence after calcar-guided short stem total hip arthroplasty: five-year results of a prospective multicentre study.

PURPOSE: Calcar-guided short-stem total hip arthroplasty (THA) has shown excellent clinical outcomes. However, the migration pattern of such prostheses and its effect on clinical outcomes are less known. Therefore, we assessed the five-year subsidence after calcar-guided short-stem THA and its implications on clinical outcomes, patient-related factors, and complications. METHODS: In this prospective multicentre study, we enrolled 213 patients (224 hips) who underwent calcar-guided short-stem THA mostly for degenerative hip diseases. We examined patients radiographically and clinically after six to 12 weeks, one year, two years, and five years. We evaluated subsidence using Einzel-Bild-Roentgen-Analyse femoral component analysis, assessed clinical outcomes, and systematically recorded all complications. RESULTS: Overall, 131 patients (133 hips) were available for final follow-up at a median of 60 months (range, 2 to 72 months). We found a mean subsidence of 0.63 ± 1.22 mm at three months, 1.03 ± 1.60 mm at one year, 1.21 ± 1.91 mm at two years, and 1.54 ± 1.97 mm at five years. Patient-related factors (sex, age, weight, and BMI) did not significantly impact subsidence at five years (P > 0.05). Additionally, the Harris hip score, pain, and satisfaction improved significantly at five years compared to pre-operative values (P < 0.0001). Lastly, five patients underwent revision. CONCLUSION: Calcar-guided short-stems revealed the highest subsidence rate within the first three months after THA and stabilisation after one year through the final follow-up examination. Moreover, patient-related factors had no influence on subsidence. Finally, clinical scores and patient satisfaction remained high at five years.

Short stem hip arthroplasty with the optimys prosthesis is a safe and effective option for obese patients: a mid-term follow-up multicenter study.

INTRODUCTION: Short stems are a valuable option in young patients undergoing total hip arthroplasty (THA) because of their bone stock preserving properties facilitating revision hip arthroplasty. Although the effect of obesity on conventional THA is well studied, data about short stem THA in obese patients are lacking. Therefore, this study aimed to investigate the influence of obesity on complications, revisions, and outcome after short stem THA. MATERIALS AND METHODS: This multicenter, observational cohort study included patients undergoing short stem THA with the optimys prosthesis. Follow-up examinations were performed at specific intervals up to 7 years postoperatively. Operation characteristics, general and specific complications, revisions, VAS rest pain, VAS load pain, VAS patient satisfaction, and Harris Hip Score (HHS) were recorded and statistically compared between obese (BMI ≥ 30 kg/m2) and non-obese (BMI < 30 kg/m2) patients. RESULTS: Of the 224 patients included with a mean follow-up of 87.2 months (range 81.9-104.0), 69 were assigned to the OB group and 155 to the non-OB group. A minimally invasive approach was significantly less often selected in obese patients (p = 0.049), whereas operating time and length of hospital stay were not significantly different. The rate of general and specific complications did not significantly differ between both groups. Survival of the optimys prosthesis was 99.1% at 7-year follow-up and one patient per group had to undergo revision surgery. VAS rest pain, load pain, and satisfaction improved from preoperatively to postoperatively in both groups without a significant difference between both groups. While the HHS was improved from preoperatively to postoperatively, obese patients showed a significantly lower HHS at the 7-year follow-up (p = 0.01) but still exhibited an excellent scoring above the PASS threshold. CONCLUSION: Short stem THA with the optimys prosthesis is a safe and effective option also in obese patients with an excellent clinical outcome and a low complication rate.

Subsidence analysis of a cementless short stem THA using EBRA-FCA - A seven-year prospective multicentre study.

Background: Metaphyseal fixation of short stem THA allows for minimally invasive surgery, less bone removal, improved bone load transfer and reduced stress shielding. Short stems facilitate the anatomic restoration i.a. of leg length, femoroacetabular offset, and center of rotation. However, metaphyseal fixation might cause impaired primary and/or secondary stability resulting in an inherent tendency for early axial migration and aseptic loosening eventually. The objective of this study was to investigate the long-term outcome and migration pattern of a calcar-guided short stem. Methods: In a prospective multicenter study, 213 patients (224 THAs) were enrolled. Patients were followed for up to 84 months postoperatively. Clinical outcome was assessed using the Harris Hip Score and the VAS for pain and satisfaction. Standardized and calibrated radiographs were screened i.a. for stress shielding and loosening. Einzel-Bild-Roentgen-Analyse - femoral component analysis (EBRA-FCA) was used to detect longitudinal subsidence. Results: At 7 year follow-up, n = 139/224 cases were available for analysis. All clinical parameters improved significantly (p < 0.001) and improvement persisted. There were no radiographic changes indicating stress shielding. EBRA-FCA revealed a mean subsidence of -1.44 mm followed by a stabilization. Weight >80 kg (p = 0.115), BMI <30 kg/m2 (p = 0.282), male gender (p = 0.246), and age <65 years (p = 0.304) seemed to be associated with a higher risk for migration. The cumulative revision rate was 2.23%. Revisions due to stem migration (0.89%) occurred early (mean time between index surgery and revision: 3.3 months). Conclusions: If at all, there appears to be a pronounced initial subsidence, which stabilizes thereafter. Stem migration was rarely a compelling reason for failure or revision. Demographics do not seem to have a significant effect on migration pattern. The absence of radioluce lines, resorption or hypertrophy of the proximal femora support the hypothesis of a reduced stress shielding for metaphyseal anchoring short stems.

Microsurgical Reconstruction in Orthopedic Tumor Resections as Part of a Multidisciplinary Surgical Approach for Sarcomas of the Extremities.

A central element of modern sarcoma therapy is complete surgical tumor resection with an adequate safety margin, embedded in an interdisciplinary multimodal therapy concept. Along with ensuring patient survival, functional limb preservation is an important goal for sarcomas of the extremities. This review provides an overview of the relevant literature on indications and goals of reconstructive options, the scope and contribution of microsurgical reconstructive procedures, and the associated interdisciplinary decision making and workup. Furthermore, the impact of (neo)-adjuvant therapy on reconstructive decisions will be highlighted. These aspects will be illustrated by four comprehensive case studies that demonstrate both useful strategies and the need for individually tailored therapies. Nowadays, extremity-preserving therapy is possible in more than 90% of sarcomas. Technical and procedural innovations such as microsurgery and microsurgical reconstructive procedures have significantly contributed to this evolution of therapy.

Bone Preservation in Total Hip Arthroplasty.

BACKGROUND: Preserving bone stock in younger and more active patients after total hip arthroplasty (THA) is important for future revision. Newer prosthesis designs, including short femoral stems and isoelastic acetabular cups, are likely to preserve more bone stock. However, long-term follow-up studies on bone remodeling after short-stem THA with an isoelastic monoblock acetabular cup are few. Therefore, we evaluated bone preservation after THA using these prostheses at a 5-year follow-up. METHODS: This prospective observational study is a 5-year follow-up of our previously reported 2-year observational study on the same cohort of patients. We included 45 patients with primary osteoarthritis treated with a calcar-guided femoral short-stem prosthesis and a monoblock press-fit acetabular cup. We evaluated bone mineral density (BMD) around the prostheses using dual-energy X-ray absorptiometry and reported functional outcomes preoperatively and at 3, 12, 24, and 60 months postoperatively. All complications were recorded. RESULTS: At the final follow-up, the BMD was comparable with that at 24 months in Gruen zones 3, 4, 5, 6, and 7, whereas it significantly differed in Gruen zones 1 (P < .0001) and 2 (P < .004). On the acetabular side, the BMD leveled off similarly in all DeLee and Charnley zones between 24 and 60 months (P > .05). Moreover, all measured clinical outcomes significantly improved (P < .001). One perioperative dislocation was reported. CONCLUSION: Patients undergoing THA with a calcar-guided femoral short-stem prosthesis and a monoblock acetabular cup can expect preservation of bone stock over a longer follow-up with excellent clinical outcomes and few complications.

Femoral antetorsion after calcar-guided short-stem total hip arthroplasty: A cadaver study.

Calcar-guided short stems in total hip arthroplasty (THA) permit surgeons to successfully reconstruct postoperative femoroacetabular offset, accurately restore leg length, and adequately re-establish a wide range of caput-collum-diaphyseal angles. However, their effect on femoral antetorsion is less known. Indeed, controlling antetorsion of the femoral stem can be challenging because of the differences in individual femoral geometry and curvature. Therefore, we investigated if calcar-guided short-stem THA alters femoral antetorsion and compared it with conventional-stem THA. Using 12 Thiel-fixed, full-body cadaver specimens from donors without known hip disorders, we compared an uncemented calcar-guided femoral short-stem prosthesis with an uncemented conventional straight-stem prosthesis. In a paired study setup, each specimen received a calcar-guided short stem on one side and a conventional stem on the other. On the acetabular side, all specimens received a press-fit, monobloc acetabular cup. Femoral antetorsion angles were measured using the Waidelich method, and pre- and post-operative angles of both sides were recorded. The mean preoperative femoral antetorsion angles were similar in both groups (24.8° ± 7.5° vs. 23.8° ± 6.1°, p = 0.313). Mean postoperative femoral antetorsion angles were 23.0° ± 5.5° in short-stem and 13.5° ± 7.1° in conventional-stem hips. Short-stem hips had a small but nonsignificant difference in femoral antetorsion angles pre- and post-operatively (1.8° ± 3.2°, p = 0.109), while the difference for conventional-stem hips was much larger and highly significant (10.3° ± 5.8°, p < 0.001). Calcar-guided short-stem THA effectively restores femoral antetorsion. However, how this affects long-term clinical outcomes and complications warrants further exploration.

Peri-acetabular bone remodelling after uncemented total hip arthroplasty with monoblock press-fit cups: an observational study.

BACKGROUND: Bone stock preservation in total hip replacement is essential to allow for later revisions in an increasingly younger and fitter index patient population. While contemporary modular press-fit acetabular cups lead to rigid fixation with equatorial stress and central osteolysis, more elastic fixation may cause different peri-acetabular bone remodelling. The purpose of this study was to investigate changes in peri-acetabular bone mineral density (BMD) in uncemented elastic fixation with monoblock press-fit cups. METHODS: This prospective observational study included 45 patients with monoblock cups. We evaluated peri-acetabular BMD using dual-energy X-ray absorptiometry and reported functional outcomes and complications. RESULTS: At a mean follow-up of 24.2 ± 2.2 months, we found that BMD stabilised in DeLee and Charnley zones I and III and recovered to baseline value in zone II. The mean Harris Hip Scores improved significantly from 56.9 ± 20.0 to 97.2 ± 4.0 (p <  0001). Other than one peri-operative dislocation, we saw no post-operative complications. CONCLUSIONS: We found favourable adaptive bone changes with BMD stabilisation in the equatorial zones and recovery to pre-operative values in the central zone. Additionally, excellent clinical outcomes and few prosthesis-related complications strengthened the favourable results of monoblock acetabular cups. TRIAL REGISTRATION: Registration number DRKS00017076.

Femoral bone remodeling after short-stem total hip arthroplasty: a prospective densitometric study.

PURPOSE: Due to improved prosthesis designs and surgical techniques, indications for total hip arthroplasty (THA) now include younger and more active patients. Preserving bone stock and soft tissue in these patients is paramount to allow for future revision. Designed for anatomical reconstruction, short femoral stems have the potential to reduce adaptive bone loss and stress shielding. To confirm this, we evaluated bone remodeling around a short femoral stem and the accuracy of hip joint reconstruction. METHODS: This prospective observational study involved 46 patients with short-stem THA for clinical and radiographic analysis. We evaluated bone remodeling by Gruen zone using dual-energy X-ray absorptiometry in 45 patients and assessed the accuracy of hip joint reconstruction using caput-collum-diaphyseal angles. Additionally, we reported functional scores and pain. RESULTS: Patients were followed for a mean of 24.1 (SD 2.2) months. Bone mineral density increased mainly in the lateral region (Gruen zones 2 and 3) and in the distal-medial region (Gruen zone 5), suggestive of lateral loading. Most caput-collum-diaphyseal angles remained stable after surgery, especially in patients with varus hips. Harris Hip Scores improved significantly, from 57.2 (SD 20.0) pre-operatively to 97.2 (SD 4.0) at 24 months post-operatively (P < 0.0001). Finally, we encountered one peri-operative dislocation but no post-operative complications. CONCLUSION: Short femoral stems successfully limited stress shielding and minimized periprosthetic bone loss without compromising primary stability. We were able to accurately reconstruct anatomical relationships in most patients. Finally, excellent clinical outcomes and low complication rates confirmed the favourable results of short-stem THA. TRIAL REGISTRATION: DRKS00017076.

Detection of circular telomeric DNA without 2D gel electrophoresis.

The end of linear chromosomes forms a lasso-like structure called the t-loop. Such t-loops resemble a DNA recombination intermediate, where the single-stranded 3' overhang is arrested in a stretch of duplex DNA. Presumably, such a t-loop can also be deleted via a recombination process. This would result in the occurrence of circular extrachromosomal telomeric DNA (t-circles), which are known to be abundantly present in immortal cells engaging the recombination-based alternative lengthening of telomeres pathway (ALT pathway). Little is known about the basic mechanism of telomeric recombination in these cells and what ultimately causes the generation of such t-circles. Current standard procedures for detecting these molecules involve 2D gel electrophoresis or electron microscopy. However, both methods are labor intense and sophisticated to perform. Here, we present a simpler, faster, and equally sensitive method for detecting t-circles. Our approach is a telomere restriction fragment assay that involves the enzymatic preservation of circular DNA with Klenow enzyme followed by Bal31 degradation of the remaining linear DNA molecules. We show that with this approach t-circles can be detected in ALT cell lines, whereas no t-circles are present in telomerase-positive cell lines. We consider our approach a valid method in which t-circle generation is the experimental readout.