John N. Insall Award: Randomized Clinical Trial of Cementless Versus Cemented Tibial Components: Durable and Reliable at a Mean 10-Years Follow-Up.

BACKGROUND: Cementless fixation is gaining popularity for primary total knee arthroplasties (TKAs). The prior 5-year results of our randomized clinical trial that included 3 different tibial designs found minimal differences. The purpose of the current study was to investigate the 10-year results in the same cohort. METHODS: Between 2003 and 2006, 389 primary TKAs were randomized: traditional modular cemented tibia (135); hybrid (cemented baseplate with uncemented pegs) monoblock tibia (128); and cementless monoblock tibia (126). Implant survivorships, radiographs, and clinical outcomes were analyzed. Mean age at TKA was 68 years (range, 41 to 85), 46% were male, and mean body mass index was 32 (range, 21 to 59). The mean follow-up was 10 years. RESULTS: The 10-year survivorship free of any revision was similar between the hybrid monoblock and cementless monoblock groups at 96%, but lower (89%) for the traditional modular cemented tibia (P = .05). The traditional modular cemented tibia group had significantly more revisions for aseptic tibial loosening than the other 2 groups (7 versus 0%) at 10 years (P = .003). The traditional modular cemented tibia group had significantly more nonprogressive radiolucent lines than the hybrid and cementless monoblock groups (24, 12, and 9%, respectively). Clinical outcomes were similar and excellent between all 3 groups. CONCLUSION: Cementless and hybrid monoblock tibial components have excellent implant survivorship (96%) with no cases of aseptic tibial loosening to date. The traditional cemented modular tibial group had a 7% cumulative incidence of aseptic loosening at 10 years. LEVEL OF EVIDENCE: Level I, Prospective Randomized Control Trial.

Macrophage Polarization and the Osteoimmunology of Periprosthetic Osteolysis.

PURPOSE OF REVIEW: Joint replacement has revolutionized the treatment of end-stage arthritis. We highlight the key role of macrophages in the innate immune system in helping to ensure that the prosthesis-host interface remains biologically robust. RECENT FINDINGS: Osteoimmunology is of great interest to researchers investigating the fundamental biological and material aspects of joint replacement. Constant communication between cells of the monocyte/macrophage/osteoclast lineage and the mesenchymal stem cell-osteoblast lineage determines whether a durable prosthesis-implant interface is obtained, or whether implant loosening occurs. Tissue and circulating monocytes/macrophages provide local surveillance of stimuli such as the presence of byproducts of wear and can quickly polarize to pro- and anti-inflammatory phenotypes to re-establish tissue homeostasis. When these mechanisms fail, periprosthetic osteolysis results in progressive bone loss and painful failure of mechanical fixation. Immune modulation of the periprosthetic microenvironment is a potential intervention to facilitate long-term durability of prosthetic interfaces.

Has There Been a Change in the Age of Presentation of Patients With DDH After the Implementation of a Dedicated Ultrasound-screening Program?

BACKGROUND: We sought to determine if the age of patients presenting to a tertiary subspecialty hospital dedicated to pediatric orthopaedics has changed over the last 21 years and determine if a dedicated ultrasound-screening program implemented in 2006 made any difference. METHODS: We reviewed the hospital charts for 9299 patients diagnosed with developmental dysplasia of the hip (DDH) and determined the age at the time of presentation; this was a consecutive series of all patients presenting between 1998 and 2019. We determined the diagnosis and age from the chart, 8011 were female (86.15%), and 1288 were male (13.85%). The left hip was affected in 4588 cases (49.34%), the right hip in 1824 cases (19.62%), and there were 2887 bilateral cases (31.05%). RESULTS: Over the 21 years, the mean age of presentation was 2.36 years (range, 0.1 to 17 y). In 1998, the mean age was 2.49 years (range, 0.1 to 16 y). In 2006, a dedicated ultrasound-screening clinic was instituted. The mean age decreased to 1.70 years in 2019 (range, 0.1 to 14 y). The mean age at presentation decreased significantly from 2.65 years, between 1998 and 2005, to 2.19 between 2006 and 2019 (P=0.0067). CONCLUSIONS: The implementation of a dedicated ultrasound-screening protocol was significantly correlated with a decrease in the mean age of diagnosis of DDH. The results of treatment of DDH are known to be better the sooner the diagnosis is made. Given that the age of presentation remains a challenge, especially in developing countries, a dedicated ultrasound-screening program is one step to improve our ability to detect DDH in patients at a younger age. LEVEL OF EVIDENCE: Level IV-diagnostic.

What Are the Rate and Risk Factors for Developing a Complication With the Pavlik Method for the Treatment of Hip Dysplasia?

BACKGROUND: The Pavlik method for the treatment of developmental dysplasia of the hip (DDH) has been proven successful for over 85 years. The high success rate and reproducibility have made it the mainstay of treatment. METHODS: We performed a retrospective cohort study of patients with DDH treated with the Pavlik method between September 2016 and August 2018 with at least 24 months of follow up in a single academic center. We excluded patients with neuromuscular conditions, teratologic dislocations, and arthrogryposis. We identified and included a total of 307 patients in the analysis. There were 66 patients with dysplasia, 97 with instability, and 144 with a dislocation. Data collected included age at initiation of the Pavlik method, diagnosis (isolated dysplasia, subluxation, or dislocation), duration of treatment, follow up duration and any complication. At final follow up, anteroposterior radiographs of the pelvis were used to determine the Severin classification. RESULTS: Major complications were proximal femoral growth disturbance (5.8%) and femoral nerve palsy (0.98%). Multivariate analysis showed that an initial diagnosis of a dislocated hip (odds ratio, 2.20; P<0.01), was significantly associated with developing a complication. At final follow up, we found Severin type I or II radiographic findings in 100% of patients with dysplasia, 95% of patients with instability and 54% of patients with dislocation (P=0.001). CONCLUSIONS: Complications are not entirely uncommon when the Pavlik method is used for the treatment of DDH. The overall rate of major complications was 7%. The Pavlik method is safe, and independent risk factors for complications were being over 5 months of age and having a dislocated hip at initial presentation. LEVEL OF EVIDENCE: Level IV-cohort study.

Acetabular reinforcement rings associated with allograft for severe acetabular defects.

Acetabular revisions with severe bone defects can be challenging procedures. Several grading systems have been set into place to help the surgeon adequately gauge the degree of bone loss within the acetabulum. Internationally innovative research in orthopedics and bio-engineering has helped with progression of successful techniques and rings to re-establish the normal anatomy of the hip. The purpose of this review is to evaluate the outcomes of the different acetabular reinforcement rings in the setting of severe acetabular defects. A successive report of relevant data from the literature of multiple techniques will be provided. The procedures include the cup-cage, the Müller ring, the Ganz Ring, the Kerboull acetabular reinforcement device (KARD), the graft augmentation prosthesis (GAP) ring, and the Burch-Schneider ring. The main focus of this overview is rings only; other devices such as trabecular augments, custom-made cages, or oblong cups are not discussed. Furthermore, a special emphasis on the surgical technique of the KARD is also given. Procedures using these rings are usually associated with bone grafts either bulk or morselized. When considering the available data on these various rings used for reconstruction of the severely damaged acetabulum, the cup-cage, the KARD, and the Burch-Schneider ring appear to be reliable options for more successful long-term outcomes.

Knee arthroplasty and lawsuits: the experience in France.

PURPOSE: Data regarding knee arthroplasty and lawsuit are scarce. With the expected increase in knee arthroplasty over the next 25 years, the number of claims might follow the same trend. Therefore, the most frequent causes of litigation after knee arthroplasty in France, and what is considered as malpractice by the expert, were determined. METHODS: Over 8-year period, data gathered from a French private insurance company specializing in malpractice for private practitioners were analyzed. Demographics, type of knee arthroplasty, reason for claim, details of the legal procedure and the expert's decision were reviewed. RESULTS: One hundred and five claims were processed by four jurisdictions. Most of the cases concerned primary total knee arthroplasty. Surgeons and anesthesiologists were charged in 84 and 16 % of claims, respectively. The most frequent causes of litigation were infection, neurological deficit and unsatisfactory result, whereas the most common reasons for the surgeon's liability, as stated by the expert, were delay in diagnosis or treatment of a complication, infection and technical error. CONCLUSION: Our findings show that frequent complications are not those which raise most of the claims. Patients sue the surgeon when the outcome of the surgery is different from what they were expecting. An unsatisfactory result, according to the patient's point of view, is the second most frequent cause of claim. LEVEL OF EVIDENCE: IV, Economic and Decision Analysis. See the Guidelines for Authors for a complete description of levels of evidence.

Total ipsilateral C7 root neurotization to the upper trunk for isolated C5-C6 avulsion in obstetrical brachial plexus palsy: a preliminary technical report.

BACKGROUND: C5-C6 root avulsion in obstetrical brachial plexus palsy (OBPP) is a rare injury with poor prognosis usually associated with breech delivery. The treatment is challenging and requires high microsurgical skills. The triple nerve transfer (spinal accessory nerve, ulnar fascicles, and triceps long or lateral head branch) represents the gold standard treatment. The total ipsilateral C7 nerve root neurotization is a promising technique, which has never been described in OBPP. OBJECTIVE: The total ipsilateral C7 nerve root is used as a neurotizer transferred to the upper trunk as an alternative method to other intra- or extra-plexual reconstruction techniques. METHODS: During brachial plexus surgical exploration, an intraoperative neurostimulation was performed to confirm the integrity of C7 and the lesion of C5 and C6. The entire C7 nerve root and the upper trunk are cut. The C7 root was transferred to the upper trunk with a fibrin sealant. RESULT: This technique was easily performed with a single approach and avoided intercalated nerve grafts. The C7 nerve root provided a large number of nerve fibers with an adequate diameter to be transferred to the upper trunk. We illustrated this technique with a typical case of a child at 8 years of follow-up. CONCLUSION: The total ipsilateral transfer of the C7 root to the upper trunk is a viable alternative procedure for newborns with C5-C6 avulsion.

Evaluation of a method for the assessment of anterior acetabular coverage and hip joint space width.

OBJECTIVE: The false-profile view (FP) is an oblique view of the acetabulum and a true lateral view of femur and joint. It evaluates anterior and posterior hip joint space width (JSW) and anterior acetabular coverage using the vertical-center margin angle (VCA). The biplanar slot scanner (SS) allows simultaneous bilateral acquisitions of oblique views of hip joints. The aim of this work was to compare SS versus FP for the evaluation of VCA and JSW and to test its reproducibility and validity. MATERIALS AND METHODS: A prospective study of 28 patients (55 hips) with hip pain was performed from November 2011 until May 2012. Two readers measured VCA and JSW. JSW was normalized by the diameter of the femoral head for each technique. The radiation exposure was recorded and compared between the two modalities. Student's t test and the Pearson's correlation assessed the agreement between SS and FP. The intraclass correlation coefficient (ICC) was used to assess the interobserver agreement. RESULTS: The mean VCA angle was 32.1° (± 7.1°) and 30.3° (± 8.5°) with FP and SS, respectively. The coefficient of correlation was 0.90 (p < 0.01). The coefficient of correlation of normalized JSW was 0.83, 0.85, and 0.87 at anterior, vertical, and posterior points, respectively). The ICC was between 0.69 and 0.81 for each modality. The mean radiation exposure was 1.33 (± 0.02) mGy versus 8.69 (±0.04) mGy for FP and SS, respectively (p < 0.0001). CONCLUSIONS: SS has the potential advantages of simultaneous bilateral acquisition, higher standardization, and is less irradiating. SS is reliable for coxometry.

Ninety-day morbidity in patients undergoing primary TKA with discontinuation of warfarin and bridging with LMWH.

We asked whether patients under long-term warfarin and managed with current guidelines regarding bridging therapy have a higher complications rate within ninety days following total knee arthroplasty. We retrospectively identified 38 patients under long-term warfarin. They were match-paired with 76 control patients. Our results showed a significant increased rate of complications (42.1% vs. 6.9%, P < 0.001) and re-operation (21.1% vs. 5.2%, P < 0.001) in the warfarin group. The difference was related to the number of hematomas requiring surgical evacuation. The warfarin group had a significantly higher rate of blood loss, blood transfusion, and length of hospital stay. Our data suggest that current guidelines for preoperative warfarin management are associated with a high rate of bleeding complications and reoperations following TKA.

Doctor, what does my knee arthroplasty weigh?

The aim of this study was to compare the weight of the total knee arthroplasty (TKA) implants and the weight of the natural knee. A prospective study was conducted with two different brands of cemented primary TKA. During the procedure, we collected the removed bone, soft tissues and the post-implantation cement and weighed them all separately at the end. In both groups, the implants plus cement were significantly heavier than the removed bone and soft tissues. The average weight gained was 266.7 ± 35.1 g for group 1 and 279.1 ± 48.7 g for group 2. This significant local weight gained after TKA is a new parameter that should be taken into account for further studies and when creating new implants.

Does the Day of the Week or the Time of Day Affect the Length of Stay or Readmission Rate for Pediatric Orthopedic Admissions?

PURPOSE: Health care institutions are searching for system-wide approaches to reduce costs while maintaining quality and improving patient outcomes. Hospital length of stay (LOS) and readmission rate (RR) are variables that significantly impact health care costs. This investigation aimed to determine if there was a difference in the LOS and the RR for pediatric orthopedic patients admitted overnight or during the weekend. MATERIALS AND METHODS: We analyzed 243 admissions for pediatric orthopedic surgery cases between September 2016 and August 2018 at a single-specialty orthopedic hospital. We categorized admissions into elective surgeries, infectious etiologies, and trauma and accidents. We compared the time and day of the week of admission to the average LOS and RR. RESULTS: The mean LOS of the entire cohort was 2.93 days. The mean LOS for trauma admissions was 1.90 days, the mean LOS for elective surgeries was 3.34 days, and the mean LOS for infections was 4.11 (p = 0.00009). The mean LOS for patients admitted on a weekday was 3.00 days; the mean LOS for patients admitted on the weekend was 2.33 days (p = 0.28). The mean LOS for patients admitted between 6:00 AM and 6:00 PM was 3.12 days, and the mean LOS for patients admitted between 6:00 PM and 6:00 AM was 2.66 days (p = 0.22). The mean LOS for patients admitted during regular operating hours was 3.12 days, and the mean LOS for patients admitted during off-hours was 2.67 days (p = 0.22). The mean RR for trauma admissions was 0.0%, the mean RR for elective surgeries was 4.5%, and the mean for infections was 3.7% (p = 0.1073). The mean RR for patients admitted on a weekday was 3.2%, and the mean RR for patients admitted on the weekend was 0.0% (p = 0.37). The mean RR for patients admitted between 6:00 AM and 6:00 PM was 4.2%, and the mean RR for patients admitted between 6:00 PM and 6:00 AM was 1.0% (p = 0.15). The mean RR for patients admitted during regular operating hours was 4.2%, and the mean RR for patients admitted during off-hours was 1.0% (p = 0.14). CONCLUSION: This study showed no relationship between the day or time of admission and the LOS or RR for pediatric orthopedic admissions. Our results support the institutional goal of maintaining operations overnight and on weekends while not compromising patient outcomes.

A novel antibacterial compound decreases MRSA biofilm formation without the use of antibiotics in a murine model.

Despite significant advancements in material science, surgical site infection (SSI) rates remain high and prevention is key. This study aimed to demonstrate the in vivo safety and antibacterial efficacy of titanium implants treated with a novel broad-spectrum biocidal compound (DBG21) against methicillin-resistant Staphylococcus aureus (MRSA). Titanium (Ti) discs were covalently bound with DBG21. Untreated Ti discs were used as controls. All discs were implanted either untreated for 44 control mice or DBG21-treated for 44 treated mice. After implantation, 1 × 107 colony forming units (CFU) of MRSA were injected into the operating site. Mice were killed at 7 and 14 days to determine the number of adherent bacteria (biofilm) on implants and in the peri-implant surrounding tissues. Systemic and local toxicity were assessed. At both 7 and 14 days, DBG21-treated implants yielded a significant decrease in MRSA biofilm (3.6 median log10 CFU [99.97%] reduction [p < 0.001] and 1.9 median log10 CFU [98.7%] reduction [p = 0.037], respectively) and peri-implant surrounding tissues (2.7 median log10 CFU/g [99.8%] reduction [p < 0.001] and 5.6 median log10 CFU/g [99.9997%] reduction [p < 0.001], respectively). There were no significant differences between control and treated mice in terms of systemic and local toxicity. DBG-21 demonstrated a significant decrease in the number of biofilm bacteria without associated toxicity in a small animal implant model of SSI. Preventing biofilm formation has been recognized as a key element of preventing implant-related infections.

The basic science of periprosthetic osteolysis.

Total joint arthroplasty has revolutionized the treatment of arthritic and degenerative conditions for many joints in the body; however, wear debris is continuously generated with day-to-day use of an artificial joint. Excessive production of wear by-products induces a foreign body and chronic inflammatory reaction that accelerates periprosthetic bone destruction and inhibits bone formation. The specific biologic reaction is dependent on the type, amount, and characteristics of the by-products of wear, along with individual genetic variations. For polymeric and ceramic particles, the inflammatory reaction is generally nonspecific and nonimmune; however, with metallic by-products, a type IV, T lymphocyte-mediated, antigen-dependent immune reaction can occur in some patients. The production of proinflammatory cytokines, chemokines, reactive oxygen species, and other mediators is upregulated by wear particles. Animal models have shown that the biologic reaction to wear particles is systemic in nature, not a localized event. Mechanical stimuli and the presence of endotoxin also appear to be important. Efficacious biologic treatments of periprosthetic osteolysis are not yet available. Research continues with the hope that viable strategies for preventing and treating particle-induced osteolysis will be introduced in the future, thus mitigating the need for revision surgery.

Total joint replacement and blood loss: what is the best equation?

With the population aging, total joint replacements which are an effective method to restore patient's mobility are an increasing necessity. However, such operations are known to entail serious blood loss, which may have dramatic consequences in patients with chronic diseases or when the prosthesis is revised, a situation where the blood loss is even higher. Therefore, formulas to better estimate the blood loss are available. These formulas may also be used for clinical studies to compare blood loss between different joint replacement techniques. The aim of this review is to provide a clear understanding of the formulas and to help physicians to further improve their blood loss estimation. Moreover, surgeons will then be able to choose the most accurate and user-friendly formula for more comparable data between clinical studies.

Cost-Effectiveness Analysis of Treatment of Radial Head Subluxation.

PURPOSE: Radial head subluxation (RHS), also called nursemaid's elbow, is a common injury in young children treated by various health care providers. The diagnosis typically does not require radiographs, but they are often ordered in the emergency room. This study aimed to determine if there was a difference in the efficacy, cost, and amount of radiographs taken in RHS treatment according to the provider, specifically between orthopedic surgeons and pediatricians. METHODS: We reviewed the charts of 207 patients presenting with RHS in the emergency department (mean age of presentation = 2.1 years, range: 0.3 to 6.5 years) to determine the provider treating the condition, the number of attempts at reduction, the number of radiographs taken, the post-reduction management, and total hospital cost incurred. RESULTS: One hundred forty-four patients were treated by orthopedic surgeons, 51 by pediatricians, and 13 by residents. The mean number of radiographs obtained was 0.1, 0.8, and 0.5 for groups treated by an orthopedic surgeon, a pediatrician, and a resident, respectively (p = 0.04). The mean cost for reduction of an RHS was $114, $648, and $267 for groups treated by an orthopedic surgeon, a pediatrician, and a resident, respectively (p = 0.04) Conclusion: Although all three groups were effective in treating RHS, there was a significantly reduced hospital cost and a reduced need for radiographs when the provider was an orthopedic surgeon.

Friend or foe? Inflammation and the foreign body response to orthopedic biomaterials.

The use of biomaterials and implants for joint replacement, fracture fixation, spinal stabilization and other orthopedic indications has revolutionized patient care by reliably decreasing pain and improving function. These surgical procedures always invoke an acute inflammatory reaction initially, that in most cases, readily subsides. Occasionally, chronic inflammation around the implant develops and persists; this results in unremitting pain and compromises function. The etiology of chronic inflammation may be specific, such as with infection, or be unknown. The histological hallmarks of chronic inflammation include activated macrophages, fibroblasts, T cell subsets, and other cells of the innate immune system. The presence of cells of the adaptive immune system usually indicates allergic reactions to metallic haptens. A foreign body reaction is composed of activated macrophages, giant cells, fibroblasts, and other cells often distributed in a characteristic histological arrangement; this reaction is usually due to particulate debris and other byproducts from the biomaterials used in the implant. Both chronic inflammation and the foreign body response have adverse biological effects on the integration of the implant with the surrounding tissues. Strategies to mitigate chronic inflammation and the foreign body response will enhance the initial incorporation and longevity of the implant, and thereby, improve long-term pain relief and overall function for the patient. The seminal research performed in the laboratory of Dr. James Anderson and co-workers has provided an inspirational and driving force for our laboratory's work on the interactions and crosstalk among cells of the mesenchymal, immune, and vascular lineages, and orthopedic biomaterials. Dr. Anderson's delineation of the fundamental biologic processes and mechanisms underlying acute and chronic inflammation, the foreign body response, resolution, and eventual functional integration of implants in different organ systems has provided researchers with a strategic approach to the use of biomaterials to improve health in numerous clinical scenarios.

Doctor, what does my ceramic-on-ceramic hip arthroplasty weigh?

BACKGROUND: While total hip arthroplasty (THA) is generally very successful, certain patients remain dissatisfied. A common concern, especially in younger and more active patients, is the weight the implant will add to the hip. However, there is very little data available to help guide surgeons in addressing this concern. The goal of this study was therefore to compare the weight of the total hip arthroplasty implants to that of tissue removed. HYPOTHESIS: That the weight of the total hip arthroplasty implants would exceed that removed tissue. PATIENTS AND METHODS: A prospective study was conducted in 104 patients, without interfering with surgical plans. To account for different implant designs, especially relating to stem fixation, we included both cementless (n=51) and cemented (n=53) femoral stems. During the procedure, the removed bone and soft tissues, as well as the post-implantation cement were collected and weighed. The weight of the implants was provided by the manufacturer. RESULTS: Both cemented and cementless THA implants proved significantly heavier than the removed bone and soft tissues. The median weight gained was 145g [IQR: 123-168] with the cementless implant and 241g [221-364] with the cemented implant (p<0.001). Multivariable regression analysis of patient- or implant factors influencing weight gain after THA revealed that weight gain decreased with patient BMI (ß=-1.0, 95% CI: -2.0--0.1 (p=0.034)). In contrast, weight gain increased slightly with total implant weight (ß=0.7, 95% CI: 0.6-0.8 (p≤0.001)). Further, weight gain was greater for women (ß=19.0, 95% CI: 9.1-29.0 (p≤0.001) (men 150g [135-219], women 211g [157-250] (p=0.010)) and patients who received the cemented stem (ß=40.0, 95% CI, 19.4-46.5, p≤0.001). DISCUSSION: Current models cause a two- to three-fold gain of weight at the hip joint after THA. While it is not clear whether this weight increase has any clinical repercussions, this finding can be helpful when a patient raises questions on this topic during the preoperative counseling. More research is necessary to determine whether lighter implants may be beneficial for patients. LEVEL OF EVIDENCE: III, case control study.

Erratum to 'Fracture of the Neck of a Modern Cementless, Titanium Femoral Stem' [Arthroplasty Today 6 (2020) 176-179].

[This corrects the article DOI: 10.1016/j.artd.2020.04.004.].

Surgical Management of Tibial Bone Loss in Revision Total Knee Arthroplasty: Clinical Outcomes and Radiographic Analysis of Tantalum Cones, Titanium Cones and Titanium Sleeves.

Background: The use of metaphyseal cones and sleeves has improved the ability to manage tibial bone loss in revision total knee arthroplasty (TKA). The purpose of this study was to compare the outcomes of three systems used for tibial metaphyseal reconstruction in revision TKA. Methods: We performed a retrospective review of a consecutive series of 723 revision TKAs, including 145 (20%) knee revisions using tibial cones or sleeves. We compared porous tantalum (TM) cones, titanium (Ti) cones and titanium sleeves. The mean follow-up was 2.5 years. Results: The rate of revision for any reason was similar among all groups. Revision-free survival rates were similar among all systems studied at a mean follow-up of 2.5 years (TM cones 93%, Ti cones 94%, titanium sleeves 89%). Ti cones had a lower complication rate (6%) compared to TM cones (24%) and sleeves (29%). TM cones (15%) and titanium sleeves (13%) had higher reoperation rates (for any cause) than Ti cones (2%). Radiographic loosening was higher for sleeves (11%) than TM and Ti cones (2%). Conclusion: Metaphyseal reconstruction for tibial bone loss in revision TKA using tantalum cones, titanium cones and titanium sleeves showed successful and comparable early clinical outcomes at a mean follow-up of 2.5 years with higher rates of radiographic loosening for titanium sleeves. Level of Evidence: III.