Cementless Total Hip Arthroplasty With Metasul Bearings Provides Good Results in Active Young Patients: A Concise Followup

Femoral stem extraction devices

INTRODUCTION

As the number of primary total hip arthroplasty (THA) procedures continues to increase, so too does the demand for revision surgery, with a 43-70% rise in revision THA anticipated by 2030. Femoral stem extraction in revision THA is particularly challenging and may lead to complications like femoral bone loss or fractures. However, increasing catalogue of femoral stems available for primary and revision THA has led technological advances in extraction devices to potentially overcome these limitations. This review aims to discuss the identification of femoral implants and the various femoral stem extraction devices currently available.

METHODS

A scoping review of current literature was conducted to explore currently available femoral extraction devices. The devices not available in literature but used in clinical practice have also been included. This review focused on the technical components, advantages, and limitations of different femoral extraction tools, including osteotomes, reciprocating saws, high-speed burrs, trephines, and extraction systems like the Watson Extraction System, Exodus Revision Hip System, Shukla Hip Universal Stem Extraction System, and DePuy Synthes Extractors.

RESULTS

Identifying femoral implants is a critical step in preoperative planning to allow for appropriate equipment to be available during revision surgery. The present review highlights that no single extraction device is universally applicable. Tools like flexible osteotomes, burrs, and trephines offer versatility but may risk bone damage. Advanced systems like the Watson Extraction System and Shukla Hip Universal Stem Extraction System provide more precise extraction, reducing the likelihood of cortical perforations and decreasing operative time.

CONCLUSIONS

Efficient femoral stem extraction in rTHA is essential for managing complications and preserving bone stock. While traditional tools remain valuable, the development of specialized extraction systems offers improved precision and efficiency. Preoperative planning, including accurate implant identification, and the selection of appropriate extraction devices are crucial for successful outcomes in revision hip arthroplasty.

Magnum metal-on-metal uncemented total hip replacement: 8- to 18-year outcomes of 211 cases

BACKGROUND

Reports of adverse reactions to metal debris contributed in part to a decline in use of large-bearing metal-on-metal total hip devices. We hypothesize an optimal trunnion design may reduce risk of this failure mode in large-bearing total hip arthroplasty systems. The purpose of this study is to report mid- to long-term outcomes for a single-surgeon series of 211 total hip arthroplasties using the large-bearing Biomet Magnum metal-on-metal system.

MATERIALS AND METHODS

Between December 2004 and January 2016, the primary surgeon performed 211 uncemented Magnum total hip arthroplasties in 181 patients. The average length of follow-up was 10.1 ± 3.5 years (range 8-18 years).

RESULTS

Using failure of any component as the endpoint, the overall survivorship rate was 98.1% at 10 years and 97.4% at 18 years. These eight failures (3.8% of cohort) included one case of adverse wear-related failure (0.5%), two cases of acetabular ingrowth failure (0.9%), three cases of trunnion corrosion (1.4%), one failure of late infection (0.5%), and one inappropriate revision of components for trochanteric nonunion without instability (0.5%). Excluding failed cases, all components were radiographically stable with no radiolucencies. Except for the one wear failure, ion testing revealed that 97.2% of cases were within optimal whole blood metal ion levels with the remaining ion test results within acceptable levels.

CONCLUSIONS

With the uncemented Magnum metal-on-metal total hip, we achieved 97.4% 18-year implant survivorship, exceeding the NICE criteria and registry benchmarks for implant survivorship. We observed a trunnion corrosion rate of 1.4% and no cases of instability. The single case of adverse wear-related failure was caused by acetabular component malposition.

Press-fit vs threaded acetabulum components for total hip arthroplasty - A systematic review with metanalysis

Background

Threaded acetabular components (TACs) have been shown to offer greater initial stability compared to press-fit acetabular components (PFACs). Despite these biomechanical advantages, the use of threaded cups remains. This study compares the outcomes of TACs to PFACs in total hip arthroplasty (THA), providing evidence-based data regarding their failure rates and radiological evaluation.

Methods

A meticulous research of PubMed and MEDLINE databases, following the PRISMA guidelines, was conducted, to identify all articles regarding the outcome of the use of TCAs compared to PFACs in THA. Subsequently, statistical analysis with metanalysis concerning: 1) the instances of revision due to aseptic loosening and 2) the radiological evaluations of TACs compared to PFACs and sensitivity analysis were performed.

Results

This metanalysis encompassed seven studies, enrolling 7878 cases of THA utilizing PFAC, and 6684 cases using TAC. The overall odds ratio (OR) for revision due to aseptic loosening in THA using PFAC compared to TAC was 3.10 (95 % CI 0.37-25.72). Additionally, when assessing radiolucency findings across the same categories, the pooled OR was 0.53 (95 % CI 0.26-1.08). An examination of studies with larger sample sizes revealed no statistically significant variance. After adjusting for age, no substantial difference was detected. However, upon gender adjustment, it was observed that females undergoing THA with PFAC had a 5-fold risk of revision (OR = 5.26, 95 % CI 0.25-111.91, p-value = 0.29) compared to females with TAC, although without reaching statistical significance. Moreover, females exhibited a slightly elevated risk for revision due to aseptic loosening post-PFAC THA compared to males [(OR = 5.26, 95 % CI 0.25-111.91) (OR = 2.51, 95 % CI 0.01-1051.68) respectively], and for radiolucency findings [(OR 0.74, 95 % CI 0.20-1.11) (OR 0.29, 95 % CI 0.03-3.36) respectively].

Conclusions

The PFACs remain the main option for total hip reconstruction, while TACs might be a viable alternative, especially in cases of osteoporosis.

Fixation or Revision for Periprosthetic Fractures: Epidemiology, New Trends, and Projections in the United States

BACKGROUND

Periprosthetic fractures can be devastating complications after total joint arthroplasty (TJA). The management of periprosthetic fractures is complex, spanning expertise in arthroplasty and trauma. The purpose of this study was to examine and project trends in the operative treatment of periprosthetic fractures in the United States.

METHODS

A large, public and private payer database was queried to capture all International Classification of Diseases, Tenth Revision (ICD-10) diagnosis codes for periprosthetic femoral and tibial fractures. Statistical models were created to assess trends in treatment for periprosthetic fractures and to predict future surgical rates. An alpha value of 0.05 was used to assess significance. A Bonferroni correction was applied where applicable to account for multiple comparisons.

RESULTS

In this study, from 2016 to 2021, 121,298 patients underwent surgical treatment for periprosthetic fractures. There was a significant increase in the total number of periprosthetic fractures. The incidence of periprosthetic hip fractures rose by 38% and that for periprosthetic knee fractures rose by 73%. The number of periprosthetic fractures is predicted to rise 212% from 2016 to 2032. There was a relative increase in open reduction and internal fixation (ORIF) compared with revision arthroplasty for both periprosthetic hip fractures and periprosthetic knee fractures.

CONCLUSIONS

Periprosthetic fractures are anticipated to impose a substantial health-care burden in the coming decades. Periprosthetic knee fractures are predominantly treated with ORIF rather than revision total knee arthroplasty (TKA), whereas periprosthetic hip fractures are predominantly treated with revision total hip arthroplasty (THA) rather than ORIF. Both periprosthetic knee fractures and periprosthetic hip fractures demonstrated increasing trends in this study. The proportion of periprosthetic hip fractures treated with ORIF relative to revision THA has been increasing.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Needs and Experiences of Patients Returning to Work After Total Knee Arthroplasty and Total Hip Arthroplasty: A Systematic Review and Meta-Synthesis

OBJECTIVE

The objective of this study was to conduct a systematic and comprehensive review of qualitative research to examine the physical and psychological needs, as well as work experiences, of patients undergoing total knee replacement and total hip replacement surgeries during their process of returning to work.

METHODS

A systematic review and meta-synthesis of qualitative literature was conducted. A systematic search was conducted across 8 databases to identify qualitative or mixed-methods research on the needs and experiences of individuals with total knee replacement and total hip replacement who have returned to work. The search period extended from the inception of each database to March 2023. Two researchers independently utilized a predetermined search strategy to retrieve relevant English-language studies published in any year. The included studies were assessed for quality using the Critical Appraisal Skills Program appraisal tool. Findings from the studies were then summarized and integrated using the pooled integration method.

RESULTS

There were 10 studies in total. Three key themes were identified from the original research: needs during the return to work process and rehabilitation training, faith and support to return to work, and constraints and challenges at work.

CONCLUSION

Health care professionals and employers should conscientiously consider the physical and psychological requirements of patients who have undergone total knee replacement and total hip replacement when they are resuming work, taking into account the specific constraints and challenges that may arise in the workplace. To ensure a seamless transition back to work, it is essential to develop tailored occupational interventions, implement comprehensive return to work programs, and offer patients sufficient understanding and support.

IMPACT

The findings of this study offer valuable insights into the physical and psychological needs, as well as the work experiences, of patients who have undergone total knee replacement and total hip replacement during their reintegration into the workforce. These findings have the potential to assist health care professionals and employers in providing enhanced support to facilitate successful return-to-work outcomes for patients.

Patient Frailty is Correlated With Increased Adverse Events and Costs After Revision Total Hip Arthroplasty

BACKGROUND

Frailty has been associated with poor outcomes and higher costs after primary total hip arthroplasty. However, frailty has not been studied in relation to outcomes after revision total hip arthroplasty (rTHA). This study examined the relationship between the Hospital Frailty Risk Score (HFRS), postoperative outcomes, and cost profiles following rTHA.

METHODS

In this retrospective cohort study, we identified patients who underwent rTHA from January 2017 to November 2019 in the Nationwide Readmission Database. The 3 most frequently reported diagnosis codes for rTHA were then selected: dislocation; mechanical loosening; and infection. We calculated the HFRS for each patient to determine frailty status. We compared 30-day readmission rate, length of stay, and hospitalization cost between frail and nonfrail patients, using multivariate logistic and negative binomial regressions to adjust for covariates. We identified 36,243 total patients who underwent rTHA. Overall, 15,448 patients had a revision for dislocation, 11,062 for mechanical loosening, and 9,733 for infection.

RESULTS

Compared to nonfrail patients, frail patients had higher rates of 30-day readmission, longer length of stay, and higher hospitalization cost. Frail patients had significantly higher rates of 30-day complication and 30-day reoperation.

CONCLUSIONS

Frailty, measured using HFRS, is associated with increased postoperative complications and costs after rTHA. The HFRS has the ability to efficiently identify frail patients at-risk for perioperative complications enabling care teams to better focus optimization interventions on this patient cohort.

Microsporidia (Encephalitozoon cuniculi) in Patients with Degenerative Hip and Knee Disease, Czech Republic

Total joint arthroplasty is a commonly used surgical procedure in orthopedics. Revision surgeries are required in >10% of patients mainly because of prosthetic joint infection caused by bacteria or aseptic implant loosening caused by chronic inflammation. Encephalitozoon cuniculi is a microsporidium, an obligate intracellular parasite, capable of exploiting migrating proinflammatory immune cells for dissemination within the host. We used molecular detection methods to evaluate the incidence of E. cuniculi among patients who had total hip or knee arthroplasty revision. Out of 49 patients, E. cuniculi genotypes I, II, or III were confirmed in joint samples from 3 men and 2 women who had implant loosening. Understanding the risks associated with the presence of microsporidia in periprosthetic joint infections is essential for proper management of arthroplasty. Furthermore, E. cuniculi should be considered a potential contributing cause of joint inflammation and arthrosis.

Long-term clinical outcomes of the Biomet M2a-38: a retrospective review of 335 total hip arthroplasty cases

BACKGROUND

At the turn of the century, over one-third of total hip arthroplasties comprised metal-on-metal bearings. As this patient population and their implants age, it is crucial to understand associated late failure modes and expected long-term functional outcomes. We report the long-term results of a large metal-on-metal uncemented total hip arthroplasty system with unique design characteristics compared to others that have been reported with high failure rates.

METHODS

We retrospectively analyze our prospective clinical database to determine overall implant survivorship and functional outcomes. Further, we compare these results to the clinical outcomes reported in orthopedic registries and in other published studies with similar metal-on-metal total hip arthroplasty cohorts.

RESULTS

Implant survivorship at 10 years was 99.1% and continued to 97.6% survivorship at 20 years. Implant survivorship at 20 years did not vary significantly between sexes (Male: 98.3%, Female: 97.2%; log-rank p-value = 0.46). Mean whole blood cobalt levels were 2.6 µg/L in unilateral cases, 5.3 µg/L in bilateral patients, and 3.4 µg/L for the combined cohort. Average blood chromium levels were 1.4 µg/L in unilateral patients, 2.9 µg/L in bilateral patients, and 1.8 µg/L for group combined. We observed a 0.9% rate of failure due trunnion corrosion at a mean of 13.1 years postoperatively (10.6-15.6 years) but had no bearing wear failures.

CONCLUSIONS

Our 20-year implant survivorship of 97.6% with the M2a-38 bearing surpassed registry benchmarks for THA. This large-bearing (38 mm), full hemisphere coverage metal-on-metal system had no bearing wear failures, one failure of instability, one failure of fixation, and three trunnion failures, perhaps suggesting an optimum balance between stability of the joint and the trunnion.

Acetabular Component Removal Systems

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As primary total hip arthroplasty procedures continue to rise, acetabular revision surgery will be in increasing demand.

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Treatment of acetabular component failure and associated bone defects depends on patient characteristics, the degree and location of bone loss, the ability of the columns to support biologic fixation, and the presence of pelvic discontinuity.

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In revision total hip arthroplasty, technological advances have been made to address limitations of acetabular cup removal while preserving host bone stock.

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The goal of acetabular revision reconstruction should be to obtain stable fixation and restore the hip center. The various acetabular cup removal systems are discussed.

Cementless metal-on-metal versus ceramic-on-polyethylene hip arthroplasty in under-50 year-olds with 20 to 22 years' follow-up: Was it a good idea to abandon the small-diameter metal-on-metal bearing?

In 2005 and 2011, we reported results for a comparative study of two types of 28-mm bearing (metal-on-metal (MoM) and ceramic-on-polyethylene (CoP) in active patients with respectively 5 and 12 years' follow-up. The present report is an update at a mean 20 years' follow-up, addressing 2 issues: (1) implant survival at a mean 20 years; and (2) long-term complications with the metal-on-metal bearing. Twenty-eight millimeters MoM bearings show good survival at 20 years in young active subjects. Two groups of cementless hip prostheses were compared: Metasul™ 28mm MoM versus 28mm CoP. The MoM group comprised 30 patients (39 hips), with a mean age of 40±6.7 years [range, 22.6-49 years], and the CoP group comprised 32 patients (39 hips), with a mean age of 40.5±8.7 years [range, 15-50 years]. The groups were matched in 2005 for age, activity level and preoperative Harris score. At a mean 20±5.3 years' follow-up [range, 5-23 years], in the MoM group 2 hips (5%) showed limited non-progressive acetabular osteolysis, not requiring revision surgery; in the CoP group, there were 21 revision procedures (54%), including 15 for polyethylene wear. In the MoM group, the median total blood cobalt concentration was 1.03g/L [range, 0.3-3.5] and the median chromium concentration was 1.07g/L [range, 0.3-3.2]. Twenty-year all-cause survival was 100% in the MoM group, and 46% (95% CI, 37-59%) in the CoP group (p<0.0001). At long-term follow-up, MoM implants showed better survival than CoP implants in a young active population. Level of evidence: III, matched case series.

What have we learned from 20 years of using highly crosslinked PE in total hip arthroplasty?

Slightly more than 20 years after its first clinical use, highly cross-linked polyethylene (HXLPE) has been widely adopted. Despite initial concerns about oxidation and lack of fatigue resistance, first generation HXLPE, with 15 years of follow-up and widespread use, continues to provide excellent results, even in a young, active population. Remelted HXLPE might have a lower wear rate than annealed HXLPE and will no doubt have a better resistance to oxidation. Second generation materials, consisting of polyethylene (PE) that is sequentially irradiated then annealed and PE that is infused with antioxidants, also have provided encouraging short- and medium-term results. Data from national joint registers confirm data from clinical trials. Even in more challenging cases (dual mobility, hip resurfacing, revision surgery and thin liners), HXLPE has generated promising results. However, failures (rim fractures) have been documented, including for all the latest HXLPE generations. Consequently, certain precautions must be taken during its use and close patient monitoring is necessary.

No difference in implant survival between 28-mm M2a RingLoc metal-on-metal and metal-on-polyethylene total hip arthroplasty: results from the Finnish Arthroplasty Register

BACKGROUND AND PURPOSE

Long-term outcome of small head (28 mm) metal-on-metal (MoM) total hip arthroplasty (THA) is available mainly for Metasul devices (Sulzer Medica, Winterthur, Switzerland). Biomet MoM THA was frequently used in Finland. Therefore, we assessed long-term survivorship of the M2a 28-mm RingLoc MoM THA (Biomet, Warsaw, IN, USA) and compared it with the metal-on-polyethylene (MoP) RingLoc THA from the same manufacturer.

PATIENTS AND METHODS

We conducted a register study based on THAs from the Finnish Arthroplasty Register performed between January 1, 2000 and December 31, 2007. 290 28-mm head M2a MoM THAs and 1,647 28-mm head MoP THAs (reference group) were included. The endpoint was revision for any reason, or revision for aseptic loosening, osteolysis, liner wear, or metallosis as one group. Kaplan-Meier survival estimates were calculated, and revision risks were assessed using a Cox multiple regression model, both with 95% confidence intervals (CI).

RESULTS

No difference was found in the 15-year Kaplan-Meier survivorship between the 28-mm head M2a RingLoc MoM THA and the reference group for any reason for revision (87.7% [82.9-92.1] and 83.3% [81.0-85.3], respectively). The adjusted hazard ratio (HR) for any reason for revision for the MoM THA group compared with the reference group was at least equal or better (0.70 [0.48-1.02]). Both groups presented similar survival for revision for aseptic loosening of the cup, osteolysis, liner wear, or metallosis, at 96.2% (92.7-98.0) and 95.4% (93.9-96.5), respectively.

INTERPRETATION

In the long-term survival there was no difference between the M2a 28-mm RingLoc MoM THA and 28-mm MoP THA. Further follow-up regimens for M2a 28-mm RingLoc THA patients may be unnecessary, but long-term metal ion and radiological data is needed before any formal suggestions.

Ultrasound evaluations and guided procedures of the painful joint arthroplasty

The purpose of this article is to describe the use of ultrasound for the diagnosis and treatment of painful joint arthroplasty. Ultrasound plays a crucial role in the diagnosis of the painful joint arthroplasty, especially given its unique dynamic capabilities, convenience, and high resolution. Ultrasound guidance is also instrumental for procedures in both diagnosing and in select cases, treating the painful joint arthroplasty. Topics to be discussed in this article include trends in arthroplasty placement, benefits of the use of ultrasound overall, and ultrasound evaluation of periprosthetic joint infections. We will also review the sonographic findings with dissociated/displaced components and adverse reaction to metallic debris including metallosis, trunnionosis, and metal-on-metal pseudotumors. Additionally, we will discuss ultrasound evaluation of tendon pathologies with arthroplasties, including dynamic maneuvers to evaluate for tendon impingement/snapping. Finally, we will cover ultrasound-guided joint arthroplasty injection indications and precautions. KEY POINTS: • Ultrasound is preferred over MRI in patients with joint arthroplasty and plays a crucial role in diagnosis, especially given its unique dynamic capabilities, convenience and high resolution. • It is especially beneficial for US-guided aspiration in periprosthetic joint infections; effectively used to evaluate periprosthetic fluid collections, facilitating differentiation between abscesses and aseptic collections, and tracking sinus tracts. • Recently, the diagnosis of periprosthetic joint infections has shifted focus to biomarkers in the periprosthetic fluid, specifically α-defensin, which has a high sensitivity and specificity for diagnosing infection. • Cutibacterium acnes is a major pathogen responsible for shoulder arthroplasty infections, often presenting with normal laboratory values and since slow growing, must be kept for a minimum of 14 days.

Adverse Tissue Reactions and Metal Ion Behavior After Small-Head Metasul Hip Arthroplasty: A Long-Term Follow-Up Study

Objective

To investigate the long‐term survivorship, incidence of adverse reactions to metal debris (ARMD), and metal ion behavior in patients who underwent small‐head Metasul metal‐on‐metal (MoM) total hip arthroplasty (THA).

Methods

Between February 1998 and September 2003, a retrospective study was performed on 43 consecutive patients (43 hips) who underwent unilateral cementless Metasul MoM THAs at our institution. Of them, 35 patients (nine males and 26 females) who were available for follow‐up more than 15 years after THA were enrolled in this study and underwent metal artifact reduction sequence magnetic resonance imaging (MARS‐MRI) to identify ARMD. The mean age at surgery of the patients was 59.7 years old (range, 31–83). Clinical and radiographic outcomes were evaluated retrospectively. Clinical examinations were conducted using the Harris Hip Score (HHS). Serum cobalt (Co) and chromium (Cr) ion levels and Co/Cr ratio were assessed at different postoperative periods of <5, 5–10, 11–14, and ≥15 years.

Results

The mean follow‐up period for the 35 patients included was 18.1 years (range, 15–22). The mean HHS significantly improved from 44.6 ± 11.3 points preoperatively to 89.4 ± 7.9 points at the final follow‐up (P < 0.0001). ARMD was found in 20% of the patients using MARS‐MRI. No signs of stem loosening were found clinically or radiographically, whereas cup loosening and ARMD were observed in three patients (9%), for whom revision THAs were performed. The Kaplan–Meier survival rates with revision for any reason as the endpoint were 90.9% at 5 years, 84.8% at 10 years, 84.8% at 15 years (95% CI, 67.1–93.6), and 70.3% at 20 years (95% CI, 43.6–87.0). The survival rates with revision for ARMD as the endpoint were 100% at 5 years, 96.6% at 10 years, 96.6% at 15 years (95% CI, 77.2–99.7), and 80.1% at 20 years (95% CI, 45.3–95.2). Serum Co ion level peaked at 5–10 years after THA, which was significantly higher than that <5 years; however, it decreased to the initial level after 15 years. In contrast, serum Cr ion level significantly increased at 5–10 years and then remained almost constant. Significant differences in Cr ion levels (1.0 vs 2.0 μg/L, P = 0.024) and Co/Cr ratio (1.3 vs 0.9, P = 0.037) were found between non‐ARMD and ARMD patients at >11 years postoperatively.

Conclusion

Our results suggest that increased Cr ion levels and decreased Co/Cr ratio may be signs of ARMD in patients who underwent small‐head Metasul MoM THA.

Pseudotumors in Small-Head Metal-on-Metal Total Hip Arthroplasties at a Minimum Follow-Up of 20 Years

BACKGROUND

Metal-on-metal (MOM) surfaces in total hip arthroplasty (THA) have been used widely. Serum cobalt and chromium levels have been the standard investigation for follow-up examinations, but magnetic resonance imaging (MRI) with metal artifact reducing sequences has shown good results in detecting pseudotumors. The aim of this study is to survey a significant correlation among MRI findings, serum metal levels, and clinical scores in patients with small-head MOM implants and if serum cobalt and chromium levels are sufficient in detecting patients with pseudotumors in the long-term follow-up.

METHODS

At a minimum follow-up of 20 years, 26 patients (29 THAs) of the original 98 patients (105 THAs) included in this study between November 1992 and May 1994 were available for follow-up examination. Clinical scores, serum metal ion levels, and MRIs were obtained.

RESULTS

We found mean serum cobalt levels of 1.87 μg/L (±3.44) and chromium levels of 2.23 μg/L (±2.96) and very good clinical and functional results (mean Harris Hip Score 88.6) in the long-term follow-up. Pseudotumors were detected in MRIs of 21 hips. There were no significant differences between patients with or without pseudotumors regarding serum metal levels and the correlation for clinical outcome scores, demographic data, and cup inclination. The cumulative rate of survival was still at 91.4% at 22.8 years.

CONCLUSION

This study presents the first published data on small-head MOM hips, comparing metal ion levels, pseudotumors, clinical, and radiological results in a follow-up period of more than 20 years and reveals that serum metal levels are not significantly higher in patients with pseudotumors.

LEVEL OF EVIDENCE

Therapeutic Level III.

Incidental findings detected on preoperative CT imaging obtained for robotic-assisted joint replacements: clinical importance and the effect on the scheduled arthroplasty

OBJECTIVE

To determine the type and frequency of incidental findings detected on preoperative computed tomography (CT) imaging obtained for robotic-assisted joint replacements and their effect on the planned arthroplasty.

MATERIALS AND METHODS

All preoperative CT examinations performed for a robotic-assisted knee or total hip arthroplasty were obtained. This resulted in 1432 examinations performed between September 2016 and February 2020 at our institution. These examinations were initially interpreted by 1 of 9 fellowship-trained musculoskeletal radiologists. Using a diagnosis search, the examination reports were then reviewed to catalog all incidental findings and further classify as significant or non-significant findings. Demographic information was obtained. In those with significant findings, a chart review was performed to record the relevant workup, outcomes, and if the planned arthroplasty was affected.

RESULTS

Incidental findings were diagnosed in 740 (51.7%) patients. Of those with incidental findings, 41 (5.5%) were considered significant. A significant finding was more likely to be detected in males (P = 0.007) and on the hip protocol CT (P = 0.014). In 8 patients, these diagnoses resulted in either delay or cancelation of the arthroplasty. A planned total hip arthroplasty was more likely to be altered as compared to a knee arthroplasty (P = 0.018).

CONCLUSION

Incidental findings are commonly detected by radiologists on preoperative CT imaging obtained for robotic-assisted joint replacement. Several were valuable findings and resulted in a delay or even cancelation of the planned arthroplasty after the detection of critical diagnoses, which if not identified may have resulted in devastating outcomes.

Small-head metal on metal total hip arthroplasty is associated with a high rate of complication and reoperation at mid-term follow-up

Background:

Adverse reactions to metal debris are significant complications after metal-on-metal total hip arthroplasty. Recently, late appearances of adverse reactions to metal debris and subsequent need for reoperations have been reported with small-diameter head metal-on-metal devices. We retrospectively investigated mid-term clinical outcomes of small-head metal-on-metal total hip arthroplasty.

Methods:

We reviewed 159 hips in 139 patients who had a small-head metal-on-metal total hip arthroplasty (M2a Taper; Biomet, Warsaw, IN) with a minimum 5-year follow-up and documented postoperative complications.

Results:

Focal osteolysis in either the femur or acetabulum was observed in 12 hips (7.5%, 44 months after surgery on average), with pseudotumor observed in 8 hips (5%, 120 months after surgery on average). Four hips (2.5%) had dislocations (84 months after surgery on average) and six hips (3.8%, 122 months after surgery on average) underwent reoperation.

Conclusion:

Small-head metal-on-metal total hip arthroplasty is associated with a high degree of complications at mid-term follow-up period. Considering this, we discourage the use of metal-on-metal total hip arthroplasty regardless of head size.

Survival at 11 to 21 years for 779 Metasul® metal-on-metal total hip arthroplasties

BACKGROUND

Total hip arthroplasties (THAs) bearing is one of the most important factors for hip replacement because THA survival depends on it. Metal-on-metal (MoM) bearing has lower wear than metal-on-polyethylene but lot of aseptic loosening decrease utilization. We analyze the survival rate of 28 mm Metasul® bearings after a mean follow-up of 12.9 years.

METHODS

The main objective of this study was to evaluate the survival of the MoM. We evaluate 779 consecutive THAs performed between January 1995 and December 2005 for primary osteoarthritis, congenital dysplasia classified Crowe I, or rheumatoid arthritis. Survival rate was calculated by the Kaplan-Meir method. The association between survival and age, gender, body mass index (BMI), and surface coating was investigated with a proportional odds model. The clinical assessment included Oxford score.

RESULTS

Six hundred fifty-two THAs were reviewed. Sixty-two revisions (9.5%) were performed including 34 aseptic loosening and 11 deep infections. The survival for prosthesis with any reason at 20 years was 87% (confidence interval (CI) 83-90.2) for aseptic loosening at 20 years was 90.1% (CI 87-93.8). There was no association with age, BMI, and surface coating. Gender was significant with lower aseptic loosening for men, hazard ratio = 0.45, p value = 0.035. Oxford score was 57 ± 6.7 (19-60).

CONCLUSION

The survival rate of Metasul was well and seems to be like our clinical finding. However, radiographic aseptic loosening without surgery is not included in the survival rate. The Oxford score was very good with a lot of patients with asymptomatic hip.

LEVEL OF EVIDENCE

Level IV/Retrospective study.

Is a portable accelerometer-based navigation system useful in total hip arthroplasty?: A systematic review and meta-analysis

BACKGROUND

Precise implant alignment is a crucial prognostic factor for successful outcomes following total hip arthroplasty (THA). A portable accelerometer-based navigation (PN) device may achieve the same accuracy as that achieved by the computer-assisted navigation surgery technique, with the convenience of a conventional technique. Although the usefulness of PN in THA (PN-THA) has been reported, whether it is more accurate than performing THA with a conventional technique (CON-THA) remains controversial. The difference in surgical time between PN-THA and CON-THA is also unclear. Therefore, we conducted a systematic review and meta-analysis of studies comparing results of PN-THA with those of CON-THA. We focused on the following question: is PN-THA superior to CON-THA in terms of radiological parameters and surgical time?

PATIENTS AND METHODS

A literature search was conducted in PubMed, Web of Science, and Cochrane Library, to identify studies that met the following inclusion criteria: randomised controlled trials (RCT) or non-RCT, studies involving patients who underwent PN-THA and patients who underwent CON-THA, studies including data on radiological parameters and surgical outcomes. Author names, publication year, country, study design, surgical approach, demographic characteristics of the participants (diagnosis, gender, age, and body mass index), and surgical outcomes (the radiological parameters and the surgical time) were extracted. We calculated the mean differences (MDs) for continuous data with 95% confidence intervals (CIs) for each outcome. p<0.05 was considered significant.

RESULTS

Three studies were included in this meta-analysis. The meta-analysis showed that absolute deviation of the postoperative measured angles from the target position for the cup anteversion was significantly smaller in PN-THA than in CON-THA (MD=-1.70, 95% CI=-2.91 to -0.50, [p=0.005]). There was no significant difference in the absolute deviation of the postoperative measured angles from the target position for cup abduction between the groups (MD=-1.82, 95% CI=-4.32-0.67, [p=0.15]). The surgical time was significantly longer in PN-THA than in CON-THA (MD=8.58, 95% CI=4.05-13.10, [p=0.0002]).

DISCUSSION

This systematic review and meta-analysis of studies comparing the results of PN-THA with those of CON-THA showed that the PN-THA is advantageous for precise cup implantation compared to CON-THA, although PN-THA has a longer surgical time compared to CON-THA.

LEVEL OF EVIDENCE

III.

Metasul vs Cerasul bearings: a prospective, randomized study at a mean eighteen years

BACKGROUND

The aims of our study were to compare the clinical, radiographic outcomes and survivals between second-generation metal-on-metal (Metasul) and ceramic-on-ceramic (Cerasul) bearings at a very long-term follow-up.

METHODS

A prospective, randomized study was originally performed on a consecutive series of 250 cementless, 28-mm head and primary total hip arthroplasties between 1999 and 2002. For each bearing (Metasul or Cerasul), 125 THAs were initially included. All cases were evaluated both clinically and radiographically, and survival was assessed, considering revisions for aseptic loosening or for any reason as the end points for failure.

RESULTS

At a mean 18-year follow-up, clinical and radiographic outcomes were similar. Harris Hip Score increased 30% in the Metasul group and 32% in the Cerasul group (p = 0.6). Survival free of aseptic loosening was higher for Cerasul (100%), than for Metasul (94% [CI 88-99.9]) (p = 0.04). Survival free of any revision was 91% ([CI 84-98%]) for Cerasul and 91% ([CI 84-98%]) for Metasul. Fractures of Cerasul insert occurred in four cases (3%) at a mean 12.5 ± 3.3 years (range, 6 to 17 years).

CONCLUSION

At 18 years, Cerasul demonstrated higher survivorship than Metasul considering aseptic loosening as an end point. However, Cerasul liners had high rate of fracture because of its sandwich design (thin ceramic liner into polyethylene). These implants are no more available on the market.

Projections and Epidemiology of Revision Hip and Knee Arthroplasty in the United States to 2030

BACKGROUND

As the incidence of primary total joint arthroplasty rises in the United States, it is important to investigate how this will impact rates of revision arthroplasty. The purpose of this study was to analyze the incidence and future projections of revision total hip arthroplasty (rTHA) and revision total knee arthroplasty (rTKA) to 2030. Anticipating surgical volume will aid surgeons in designing protocols to efficiently and effectively perform rTHA/rTKA.

METHODS

The national inpatient sample was queried from 2002 to 2014 for all rTHA/rTKA. Using previously validated measures, Poisson and linear regression analyses were performed to project annual incidence of rTHA/rTKA to 2030, with subgroup analyses on modes of failure and age.

RESULTS

In 2014, there were 50,220 rTHAs and 72,100 rTKAs. From 2014 to 2030, rTHA incidence is projected to increase by between 43% and 70%, whereas rTKA incidence is projected to increase by between 78% and 182%. The 55-64 and 65-74 age groups increased in revision incidence during the study period, whereas 75-84 age group decreased in incidence. For rTKA, infection and aseptic loosening are the 2 most common modes of failure, whereas periprosthetic fracture and infection are most common for rTHA.

CONCLUSION

The incidence of rTHA/rTKA is projected to increase, particularly in young patients and for infection. Given the known risk factor profiles and advanced costs associated with revision arthroplasty, our projections should encourage institutions to generate revision-specific protocols to promote safe pathways for cost-effective care that is commensurate with current value-based health care trends.

LEVEL OF EVIDENCE

IV.

Is a cementless fixation of the femoral component suitable for metal-on-metal hip resurfacing arthroplasty?

BACKGROUND

Hip resurfacing arthroplasty (HRA) typically uses a hybrid design (cemented femoral component and cementless acetabular shell) but has recently been performed with fully cementless components. There is a paucity of information on the clinical performance of these cementless designs.

METHODS

The UCLA clinical scores, SF-12 quality of life scores, complication rates, survivorship and radiographic signs of loosening or gross stress shielding of 39 hips (39 male patients) implanted with cementless HRA were compared with those of 40 hips (37 male patients) implanted with hybrid HRA during the same time frame.

RESULTS

There were no significant differences in postoperative clinical and quality of life scores, complication rates, or radiographic signs of loosening between the 2 groups. The 5-year Kaplan-Meier survivorship was 97.2% for the cementless group and 100% for the hybrid group. This difference was not significant (p = 0.3694). There were no femoral component failures in any of the 2 groups.

CONCLUSIONS

At a mean follow-up of 6 years, there is no tangible difference between the performance of cementless HRA compared to hybrid HRA. The absence of learning curve associated with this device and the potential for better preservation of femoral neck bone mineral density suggest that this technology is well suited for young patients with good bone quality seeking to resume an active lifestyle including high-impact activities.

Ten-year outcomes of cementless anatomical femoral implants after 3D computed tomography planning. Follow-up note

BACKGROUND

Pre-operative 3D planning based on computed tomography (CT) imaging is used to optimise the restitution of normal hip anatomy during primary total hip arthroplasty (THA). Although CT planning has been proven effective and reproducible, its influence on long-term THA outcomes is unknown. In this 10-year follow-up study of patients managed with the same technique of CT-planned primary anatomical THA, the objectives were to assess femoral implant survival, long-term functional outcomes, 10-year outcomes of titanium modular femoral necks, and associations with the dislocation rate. Hypothesis Pre-operative CT planning of primary THA ensures achievement of the NICE criterion of a lower than 5% femoral revision rate within 10 years.

MATERIAL AND METHODS

The study included 61 patients (61 hips) managed between 2004 and 2007 by CT-planned primary THA via the posterior approach, with an uncemented anatomical femoral component (SPS^®, Symbios); when deemed necessary by the surgeon to restore normal anatomy, a titanium modular femoral neck was used (35/61 patients). After 10 years, 17 patients had died and 3 were lost to follow-up, leaving 41 patients with a mean age of 76 years (range, 60-91 years) for re-evaluation. Clinical outcomes were assessed by determining the Harris Hip Score (HHS) and the Postel-Merle d'Aubigné (PMA) score, which were compared to baseline values. Radiographs were evaluated using the AGORA Roentgenographic Assessment system (ARA).

RESULTS

The 10-year femoral component survival rate was 96% (95%CI, 88;99%). Revision was required in 4 patients, to treat delayed peri-prosthetic fractures (n=2) or to correct initial cup malposition (n=2). No changes occurred from 2010 to last follow-up in the mean HHS (90 [95%CI, 84;95] and 91 [95%CI, 77;96], respectively) or mean PMA score (16 [95%CI, 14;17] and 15.5 [95%CI, 14;16.5], respectively). The mean ARA score was 5.2 (range, 3-6) at last follow-up. No complications related to the use of modular femoral necks were recorded. Dislocation occurred in 2 patients, but in neither was the pre-operative plan followed during surgery.

DISCUSSION

The SPS^® stem produced good 10-year clinical and radiographic outcomes. No patients experienced complications related to use of a titanium modular femoral neck. The restoration of anatomical hip geometry made possible by pre-operative CT planning provided sustained clinical improvements with a low complication rate.

LEVEL OF EVIDENCE

IV, retrospective observational cohort study.

Prevalence and natural course of pseudotumours after small-head metal-on-metal total hip arthroplasty: a minimum 18-year follow-up study of a previous report

AIMS

The present study investigated the five-year interval changes in pseudotumours and measured serum metal ions at long-term follow-up of a previous report of 28 mm diameter metal-on-metal (MoM) total hip arthroplasty (THA).

PATIENTS AND METHODS

A total of 72 patients (mean age 46.6 years (37 to 55); 43 men, 29 women; 91 hips) who underwent cementless primary MoM THA with a 28 mm modular head were included. The mean follow-up duration was 20.3 years (18 to 24). All patients had CT scans at a mean 15.1 years (13 to 19) after the index operation and subsequent follow-up at a mean of 20.2 years (18 to 24). Pseudotumour volume, type of mass, and new-onset pseudotumours were evaluated using CT scanning. Clinical outcomes were assessed by Harris Hip Score (HHS) and the presence of groin pain. Serum metal ion (cobalt (Co) and chromium (Cr)) levels were measured at the latest follow-up.

RESULTS

At final follow-up, pseudotumours were observed in 26/91 hips (28.6%). There was an increase in volume of the pseudotumour in four hips (15.4%), no change in volume in 21 hips (80.8%), and a decrease in volume in one hip (3.8%). There were no new-onset pseudotumours. There was no significant difference in HHS between patients with and without pseudotumours. At final follow-up, mean serum Co ion levels and median Co:Cr ratios were significantly greater in patients with pseudotumours, but the serum Cr ion levels were not significantly different.

CONCLUSION

At a mean 20 years of follow-up, pseudotumours were observed in 26/91 hips (28.6%) with no new-onset pseudotumours during subsequent follow-up. Most pseudotumours in small-head MoM THA were static in volume and asymptomatic with normal serum metal ion levels. Cite this article: Bone Joint J 2019;101-B:317-324.

[A retrospective study on the application of cemented polyethylene liner technique in hip revision]

Objective

To evaluate the effectiveness of cemented polyethylene liner technique in hip revision.

Methods

Based on inclusion criteria, the clinical data of 26 patients who were undergone hip revision between January 2011 and December 2013, were retrospectively reviewed. Among them, 14 cases were treated with isolated liner exchange (group A) and 12 cases were treated with cemented polyethylene liner technique (group B). There was no significant difference in gender, age, the time from primary total hip arthroplasty to revision, and the preoperative Harris score between 2 groups ( P>0.05). The post-operative Harris score and complications were compared between 2 groups, and X-ray findings of the hip joint were recorded to review the position of hip components.

Results

All patients were followed up 4.4-6.4 years (mean, 5.4 years). Except for two femoral fractures during the revision (1 in each group), there was no other complication in 2 groups. The hip pain relieved and the lame gait corrected in 2 groups. The hip's function of 2 groups improved gradually after operation, with a better Harris score at 3 months and the best at the last follow-up, compared with preoperative scores ( P<0.05). There was no significant difference in Harris score at difference time points after operation between 2 group ( P>0.05). X-ray films showed no dislocation, aseptic loosening, and other interface related complication.

Conclusion

For the cases without the chance to do change liner, cemented polyethylene liner technique has a good effectiveness. But restrict patient selection should be considered before hip revision.

Long-Term Outcomes After Metal-on-Metal Total Hip Arthroplasty With a 28-mm Head: A 17- to 23-Year Follow-Up Study of a Previous Report

BACKGROUND

Second-generation, metal-on-metal total hip arthroplasty (MoM THA) using a 28-mm head has shown favorable results compared with large head MoM THA. The purpose of this study is to evaluate the long-term outcomes of cementless primary MoM THA with a 28-mm head and the incidence of osteolysis using computed tomography.

METHODS

A total of 92 patients (53 men and 39 women) who underwent primary cementless MoM THA (114 hips) with a 28-mm head were enrolled in this study. Their mean age was 46.2 years at the time of surgery. The mean follow-up duration was 20 years. The Harris hip score, presence of thigh or groin pain, radiographic results, presence of peri-implant osteolysis, histologic analysis, and Kaplan-Meier survival curves were evaluated.

RESULTS

The mean preoperative Harris hip score of 50.5 improved to 85.1 at the final follow-up. Eight patients (8 hips) experienced groin pain, but none had thigh pain. Twelve revisions (6.2%) were performed including 10 hips for aseptic loosening with osteolysis and 2 hips for periprosthetic fracture around the stem. At 23 years, 91% of patients were free from revision of the acetabular component due to aseptic loosening and 90.1% were free from revision of both femoral and acetabular components due to any reason. Osteolysis was identified around the cup in 12 cases (10.5%) and around the stem in 7 cases (6.1%).

CONCLUSION

MoM THA with a 28-mm head showed a relatively low rate of aseptic implant loosening at a mean follow-up of 20 years.

Outcomes of Unilateral Total Hip Arthroplasty in Patients Aged Under 35 Years in Iranian Population: A Preliminary Study

Background:

The purpose of this study is to report outcomes of total hip arthroplasty (THA) in patients under the age of 35 years regarding pain and joint function.

Materials and Methods:

This preliminary analytic-descriptive study was performed in prospective consecutive series of forty-three patients younger than 35 years old who had undergone unilateral THA during a 36-month period. As the primary outcome, the severity of pain using visual analog scale (VAS) of 1–10, and as the secondary outcomes, joint range of motion (ROM) and the Harris Hip Score (HHS) were assessed in the preoperative visit, 1, 6, and 18 months after operation for each patient. Complications were recorded at 6 months and 18 months after surgery.

Results:

The data of VAS showed the mean severity of pain was significant between preoperation measurements and postoperative assessments (P < 0.001). The means of HHS and hip ROM were also statistically significant before the operation in comparison with postoperative assessments (P < 0.001 for both means). A total of 19 patients had postoperative complications including periprosthetic fracture in two patients, infection in two patients, cup loosening in three patients, limb length discrepancy in 10 patients, and heterotopic ossification in two patients. Seven patients had been readmitted.

Conclusion:

We believe THA using uncemented prosthesis has a high survivorship with low rate osteolysis in young patients with good bone stock. It is necessary to have longer follow-up to have a better evaluation on outcomes.

Midterm Prospective Comparative Analysis of 2 Hard-on-Hard Bearing Total Hip Arthroplasty Designs

INTRODUCTION

Hard-on-hard (HoH) bearing surfaces in total hip arthroplasty (THA) are commonly utilized in younger patients and may decrease mechanical wear compared to polyethylene bearing surfaces. To our knowledge, no study has prospectively compared the 2 most common HoH bearings, ceramic-on-ceramic (CoC) and metal-on-metal (MoM) THA.

MATERIALS AND METHODS

We prospectively enrolled 40 patients to undergo an MoM THA and 42 patients to undergo a CoC THA utilizing the same acetabular component. Patients were followed up for a minimum of 2 years. Comparative outcomes included clinical scores, revision or reoperation for any reason, complication rates, and radiographic outcomes.

RESULTS

The average follow-up was significantly longer in the CoC cohort (94 vs 74 months; P = .005). The CoC cohort had significantly improved Harris Hip Scores (95 vs 84; P = .0009) and pain scores (42 vs 34; P = .0003). The revision (0% vs 31%; P = .0001), reoperation (7.5% vs 36%; P = .004), and complication rates (10% vs 56%; P = .0001) were significantly lower in the CoC cohort. There were no statistically significant differences in radiographic parameters.

CONCLUSION

The clinical outcomes in the CoC cohort exceeded the MoM cohort. It is unlikely that another prospective comparative study of HoH THAs will be conducted. Our midterm results support the use of CoC THA as a viable option that may reduce long-term wear in younger patients. Close surveillance of MoM THA patients is recommended considering the higher failure and complication rates reported in this cohort.

What Is the Long-term Survival for Primary THA With Small-head Metal-on-metal Bearings?

BACKGROUND

Large-head metal-on-metal (MoM) bearing hip replacements have been shown to have a much higher rate of revision than other bearing surfaces. However, small-head (≤ 32 mm) MoM bearing surfaces have been in use for many years with several reports of satisfactory mid- to long-term survivorship. It is unclear whether the long-term survival of small-head MoM devices will continue to be satisfactory or whether the same concerns seen with the large-head MoM devices will ultimately become more prevalent.

QUESTIONS/PURPOSES

We analyzed a large national registry to ask: (1) What is the 15-year Kaplan-Meier survivorship of primary conventional THA using small-head (≤ 32 mm) MoM bearing surfaces compared with large-head MoM bearing surfaces in primary THA? (2) Is there an increased rate of revision for adverse reaction to metal debris (ARMD) in this group of patients over time?

METHODS

The Australian Orthopaedic Association National Joint Replacement Registry longitudinally maintains data on all primary and revision joint arthroplasties with nearly 100% capture. We analyzed all conventional primary THAs performed from Registry inception in September 1999 until December 31, 2015, in patients with a diagnosis of osteoarthritis and using MoM bearing surfaces ≤ 32 mm in diameter, defined as small-head MoM. The study group included 4838 primary THA with ≤ 32-mm MoM bearing surfaces. There were 2506 (51.8%) male patients and the median age of patients undergoing THA with a small-head MoM bearing surface was 64 years (range, 20-92 years of age). The outcome measure was the cumulative percent revision defined as the time to first revision using Kaplan-Meier estimates of survivorship at 15 years; reasons for revision and type of revision were also examined. We specifically investigated whether there was an increased risk of revision for ARMD in this MoM group compared with all other bearing surfaces. We compared these results with large-head MoM THAs (femoral head size > 32 mm).

RESULTS

The cumulative percent revision for small-head MoM designs at 15 years was 8.5% (95% confidence interval [CI], 7.3-9.9). The cumulative percent revision for large-head MoM at 14 years was 27.4% (95% CI, 24.8-30.2). Prostheses with a large-head MoM articulation have a higher rate of revision than small-head MoM bearing surfaces (hazard ratio after 6 years, 5.14; 95% CI, 4.1-6.5; p < 0.001). Over time, there was a gradual increase in the diagnosis of ARMD for small-head MoM and the cumulative incidence of revision for ARMD was 0.8% at 15 years.

CONCLUSIONS

Despite survival that is substantially greater than that of large-head MoM THAs, there has been a marked decrease in the use of small-head MoM designs in our registry. Although the reasons for this are likely multifactorial, the increasing incidence of revisions for ARMD among small-head MoM THAs is concerning.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Hip resurfacing before 50years of age: A prospective study of 979 hips with a mean follow-up of 5.1years

BACKGROUND

Hip resurfacing arthroplasty (HRA) is an alternative to total hip arthroplasty (THA) for the treatment of hip osteoarthritis in patients younger than 50 years. Data on revision rates after HRA are conflicting. The National Institute for Health and Care Excellence (NICE) recommends performing only those hip arthroplasty procedures associated with 10-year revision rates no greater than 5% (0.5% per year). Follow-up studies can rapidly determine whether this criterion is met. The uncertainties surrounding revision rates after HRA prompted us to design a study of prospectively enrolled patients aiming (1) to determine the revision rate after HRA performed before 50years of age and (2) to assess the functional, radiological, and biological outcomes of HRA.

HYPOTHESIS

The revision rate after HRA performed before 50years of age meets the NICE criterion.

MATERIAL AND METHODS

Consecutive patients undergoing HRA before 50years of age were enrolled prospectively. The same implant was used in all patients. Functional outcomes were assessed based on the Harris Hip Score (HHS), Postel-Merle d'Aubigné (PMA) score, 12-item Oxford Hip Score (OHS), and UCLA activity score. Radiographic outcomes were assessed, and blood levels of chromium and cobalt were assayed.

RESULTS

The study included 936 patients (979 HRAs) with a mean age of 42.7years (16.4-50.0years) at surgery and a mean follow-up of 5.1years (range: 3.1-9.0 years). All four mean functional scores were significantly improved at last follow-up vs. baseline: HHS, 95.9 (39.0-100) vs. 44.3 (18.0-83.0); PMA score, 17.6 (6.0-18.0) vs. 11.7 (3.0-16.0); OHS, 14.3 (12.0-37.0) vs. 40.6 (25.0-60.0); and UCLA activity score, 7.8 (2.0-10.0) vs. 5.6 (1.0-10.0) (p<0.0001). Mean cup inclination in the coronal plane was 42.1° (25.0°-68.0°). Mean blood cobalt level was significantly higher at last follow-up than at baseline (1.36μg/L [0.05-8.2μg/L] vs. 0.61μg/L [0.01-3.6]) (p<0.001). No patient experienced dislocation. Revision was required for 17 hips and involved changing the implant in 12 (1.2%). The 10-year survival rate with implant change, as the endpoint was 98.7% (95%CI, 97.6%-99.3%), indicating that the NICE criterion was easily met.

DISCUSSION

The NICE criterion allows the rapid identification of prostheses with insufficient survival. HRA is theoretically associated with a high risk of aseptic mechanical loosening, as it is performed in young patients who have a high level of physical activity. Nevertheless, our study showed that implant survival after HRA was better than required by the NICE criterion. Thus, HRA is a valid alterative to THA in patients younger than 50years.

LEVEL OF EVIDENCE

IV, prospective study with no control group.

Inferior Radiographic and Functional Outcomes With Modular Stem in Metal-on-Metal Total Hip Arthroplasty

BACKGROUND

Data on the association between stem type and metal-on-metal (MoM) total hip arthroplasty (THA) performance are limited. The aim of this study is to investigate the effect of stem type on the prevalence of osteolysis and radiolucency, blood metal ion levels, and functional outcomes in patients with Articular Surface Replacement THA (ASR XL), a type of MoM THA.

METHODS

We analyzed 539 unilateral MoM THAs coupled with Summit (48%), Corail (35%), or S-ROM (17%) hip stems at a mean follow-up of 6.4 years. Fifty-four percent of the patients were male, and the mean age was 60 years. We studied radiographs, patient-reported outcome measures, and ion levels.

RESULTS

Patients with S-ROM hip stems were 3.8 times more likely to have osteolysis (P = .003) and 7.6 times more likely to have radiolucency (P < .001) than those treated with Summit hip stems. In addition, patients treated with S-ROM hip stems scored worse than those with Summit hip stems in 4 of the 5 patient-reported outcome measures: Harris Hip Score, Visual Analog Scale pain, University of California at Los Angeles activity, and EQ-5D index. All these differences were statistically significant and ranged from 5% to 10%, which is clinically significant.

CONCLUSION

Patients with S-ROM hip stems had inferior functional and radiographic results compared to patients with Summit hip stems. Retrieval studies on large diameter head MoM THA and close follow-up of these patients with hip stems are needed to understand the mechanism causing the differences in outcomes between these stem types.

Dual-mobility cup in total hip arthroplasty in patients less than fifty five years and over ten years of follow-up : A prospective and comparative series

PURPOSE

We report clinical and radiological outcome of a dual mobility cup (DMC) of 2nd generation after a minimum of ten year-follow-up (FU). The goal of this work was to compare the results of this DMC in patients aged less than 55 years and in patients aged more than 55 years.

METHODS

From 2000 to 2005, a prospective and consecutive series of 119 THAs with a cementless DMC of 2nd generation (GIROS) were performed in patients aged less than 55 years and 444 in patients aged more than 55 years.

RESULTS

The mean FU was 11 years (8 to 15 years). Survivorships (failure of both components or cup loosening) were not different between patients aged less than 55 years and patients aged more than 55 years. There was no dislocation. DEVANE classification, Harris, PMA and Oxford scores improved after THA but no difference could be found between between < 55 years and > 55 years patients.

CONCLUSION

These results are better than those of first generation (BOUSQUET) DMC (77 % of survival rate at 20 years of FU). These results are in the same agreement than those of the literature: 99 % of survival rate at 14.2 years of FU for KERBOULL with a low friction arthroplasty and 96.5 % at ten years of FU for ceramic/ceramic bearing (R CHANA). The DMC for young patient is a relevant surgical option with no dislocation and excellent clinical results and survival rate at more than ten years of FU.