Kaempferol attenuates particle-induced osteogenic impairment by regulating ER stress via the IRE1α/XBP1s pathway

Periprosthetic osteolysis and subsequent aseptic loosening are the primary causes of failure following total joint arthroplasty. Wear particle-induced osteogenic impairment is recognized as an important contributing factor in the development of osteolysis, with endoplasmic reticulum (ER) stress emerging as a pivotal underlying mechanism. Hence, searching for potential therapeutic targets and agents capable of modulating ER stress in osteoblasts is crucial for preventing aseptic loosening. Kaempferol (KAE), a natural flavonol compound, has shown promising osteoprotective effects and anti-ER stress properties in diverse diseases. However, the influence of KAE on ER stress-mediated osteogenic impairment induced by wear particles remains unclear. In this study, we observed that KAE effectively relieved TiAl6V4 particles (TiPs)-induced osteolysis by improving osteogenesis in a mouse calvarial model. Furthermore, we demonstrated that KAE could attenuate ER stress-mediated apoptosis in osteoblasts exposed to TiPs, both in vitro and in vivo. Mechanistically, our results revealed that KAE mitigated ER stress-mediated apoptosis by upregulating the IRE1α/XBP1s pathway while concurrently partially inhibiting the IRE1α-regulated RIDD and JNK activation. Collectively, our findings suggest that KAE is a prospective therapeutic agent for treating wear particle-induced osteolysis, and highlight the IRE1α/XBP1s pathway as a potential therapeutic target for preventing aseptic loosening.

Cemented is not superior to cementless total knee arthroplasty for complications: a propensity score matched analysis

INTRODUCTION

There is continued debate regarding the survivorship and revision rate of cementless versus cemented total knee arthroplasty (TKA) prostheses. This includes the assessment of early revision surgery due to aseptic loosenings and periprosthetic joint infections (PJIs). Studies have not always taken into account the impact of comorbidities, such as diabetes, obesity, and tobacco. Therefore, we compared revisions in a large population of patients undergoing cemented or cementless TKAs at 90 days, 1 year, and 2 years.

METHODS

A review of an administrative claims database was used to identify patients undergoing primary TKA, either cementless (n = 8,890) or cemented (n = 215,460), from October 1, 2015 to October 31, 2020. Revision surgery for PJI and aseptic loosening were identified with diagnosis and associated procedural codes at 90 days, 1 year, and 2 years and then compared between groups. A propensity matched-analysis was performed for age, sex, Charles Comorbidity Index (CCI) > 3, alcohol abuse, tobacco use, obesity, and diabetes. Chi square tests assessed statistical significance of differences in the matched cohorts using odds ratios (ORs) with 95% confidence intervals (CIs). A P < 0.05 was defined as statistically significant.

RESULTS

Cementless TKA was associated with similar revisions rates due to PJIs at 90 days (OR, 1.04, 95% CI 0.79-1.38, p = 0.83), 1 year (OR, 0.93, 95% CI 0.75-1.14, p = 0.53, and 2 years (OR, 0.87, 95% CI 0.73-1.05, p = 0.17) in comparison to the cemented TKA cohort. The odds ratio of revision due to aseptic loosening was similar as well at 90 days (OR, 0.67, 95% CI 0.34-1.31, 0.31), 1 year (OR, 1.09, 95% CI 0.73-1.61, p = 0.76), and 2 years (OR, 1.00, 95% CI 0.73-1.61, p = 0.99).

CONCLUSIONS

This study found a comparable risk of PJI and aseptic loosening in cementless and cemented TKA when controlling for several comorbidities, such as tobacco, diabetes, and alcohol. Therefore, with proper patient selection, cementless TKAs can be performed with expectation of low risks of infections and aseptic loosenings.

High femoral offset as a risk factor for aseptic femoral component loosening in cementless primary total hip arthroplasty

PURPOSE

Lateralized stems in primary cementless total hip arthroplasty (THA) showed to be associated with aseptic femoral loosening. However, femoral head length also affects femoral offset but was not considered so far. This study analyzed the impact of high femoral offset (hFO) combinations, formed by lateralized stems or large femoral head lengths, on aseptic femoral component loosening.

METHODS

Retrospective cohort study was performed including all patients that underwent primary cementless THA at our institution between July 2004 and December 2016. Patients were screened for aseptic femoral component loosening and grouped in aseptic loosening (AL) and non-aseptic loosening (nAL) group. Medical records were screened; implant details were noted and classified in hFO and standard femoral offset (sFO) combinations. Supposed risk factors for aseptic loosening were analyzed.

RESULTS

Two thousand four hundred fifty-nine THA could be included, containing 14 THA (0.6%) with aseptic femoral component loosening. The AL group contained 11 hFO combinations (78.6%), whereas in the nAL group, 1315 hFO combinations (53.8%) were used. Subgroup analysis showed significant difference between two groups for hFO combinations (p = 0.014), age (p = 0.002), NSAR (p = 0.001), and bilateral THA on same day (p = 0.001). The multiple logistic regression analysis showed that hFO combination was the only variable for increased probability of aseptic loosening (OR, 3.7; p = 0.04).

CONCLUSION

High femoral offset combinations, formed by lateralized stems or large femoral head lengths in our collective of standard straight stems implanted by an anterior approach, show a 3.7-fold increased probability for aseptic femoral component loosening. Adjustment of the postoperative protocol may be considered in these cases to ensure proper stem ingrowth.

Dual-mobility tripod cup for revision hip arthroplasty: long-term (five to fourteen years) evaluation of a new generation cementless implant

PURPOSE

The aims of this study were to evaluate the survivorships of a new generation cementless DMC with tripod additional fixation in revision total hip arthroplasty and complications at a minimum five year follow-up.

METHODS

One hundred and fifteen revisions (THA) treated with tripod DMC performed between 2009 and 2015 were included in this retrospective study. Acetabular defects were classified as Paprosky 1 (n = 38, 33%), 2 (n = 75, 65%) or 3 (n = 2, 2%). Unipolar or bipolar revision was performed for the following indications: aseptic acetabular loosening (63%), infection (14%), aseptic bipolar loosening (11%), instability (4%), aseptic femoral loosening (3%), ALVAL (3%) and iliopsoas impingement (2%). Mean follow-up was 9.4 years ± two (range, 5 to 14).

RESULTS

At the final follow-up, a single episode of dislocation occurred within three months after the procedure (0.8%) with no revision. Three cases of aseptic loosening were diagnosed (2.6%). Four infections (3.5%) required reoperation: three required a two stage bipolar revision; one was treated by DAIR procedure. At the latest follow-up, the survivorship of the acetabular cup for aseptic loosening was 98% [95% CI (91.2-99.4)] and for any reasons was 94.4% [95% CI (90.1%-98.9%)]; the mean HHS improved from 60 points (range, 18-94 points) to 83 points (range, 37-100 points) (p < .001).

CONCLUSION

This study reports a low complication rate in favour of the use of a tripod DMC in revision THA with a satisfactory survivorship at a ten year follow-up.

Simultaneous Post and Cone Fractures of a Polyethylene Insert in a Mobile-Bearing Posterior-Stabilized Total Knee Arthroplasty

We report a novel case of the simultaneous post and cone fractures of a polyethylene (PE) insert in a mobile-bearing posterior-stabilized total knee arthroplasty. Twelve years after the primary total knee arthroplasty, the 72-year-old male patient presented with a recurring right knee instability and was diagnosed with the wear of the PE insert based on physical and radiological examinations. Revision surgery was performed. The post and cone of the PE insert had fractured simultaneously. Moreover, the femoral and tibial components were in direct contact with each other. One year post-revision, knee function had improved. To diagnose a PE breakage, such as a post or cone fracture, surgeons should consider the possibility of PE breakage even in the absence of pain since patients might complain of subjective instability only.

Epiphyseal fixation in revision total knee arthroplasty: a comparison between trabecular metal and titanium augments

INTRODUCTION

The purpose of this retrospective study was to compare the medium-term clinical and radiographic outcomes of two series of patients treated for revision TKA: one implanted with trabecular metal (TM) augments and one implanted with classic titanium augments.

MATERIALS AND METHODS

A total of 85 patients with a type 2 AORI defect underwent revision TKA and were treated either with TM epiphyseal augments directly screwed in the bone or with traditional titanium augments. There were 46 patients in the TM group and 39 patients in the titanium group included in the study. All the patients received the same varus-valgus constrained implant and no metaphyseal fixation devices were used.

RESULTS

After a mean follow-up of 66.4 months, no statistically significant difference was observed in terms of failure for aseptic loosening between the two groups (4% in the TM group and 7.8% in the titanium group, p = 0.35). The ten-year survival using aseptic loosening as endpoint was 90.5% (95% CI 94.1-98.6) in the TM group and 85% (95% CI 101.9-119.3) in the titanium group (p = 0.26). A statistically significant difference was detected for the presence of RLL. No RLL were found under the studied TM augments compared to 13.7% of the titanium augments (p = 0.01).

CONCLUSION

The use of TM augments directly screwed to the epiphysis of the femur and the tibia reduced the incidence of RLL compared to standard titanium augments during revision TKA with promising medium-term results.

Early radiological outcomes of a fully porous bridging collar in lower-limb endoprosthetic reconstructions: a case-matched retrospective series to assess osseointegration

BACKGROUND

Limb-salvage surgery involving the utilization of endoprosthetic replacements is commonly employed following segmental bone resection for primary and secondary bone tumors. This study aimed to evaluate whether a fully porous bridging collar promotes early osseous integration in endoprosthetic replacements.

METHODS

We undertook a retrospective review of all lower-limb endoprostheses utilizing a fully porous endosteal bridging collar design. We matched this cohort with a conventional extra-osteal non-porous fully hydroxyapatite-coated grooved collar cohort according to surgical indication, implant type, resection length, age, and follow-up time. At 6, 12, and 24 months post-implantation, radiographs were assessed for the number of cortices with or without osseointegration on orthogonal radiographs. Each radiograph was scored on a scale of -4 to + 4 for the number of cortices bridging the ongrowth between the bone and the collar of the prosthesis. Implant survival was estimated using the Kaplan-Meier method, and the mean number of osseointegrated cortices at each time point between the collar designs was compared using a paired t-test.

RESULTS

Ninety patients were retrospectively identified and analyzed. After exclusion, 40 patients with porous bridging collars matched with 40 patients with conventional extra-osteal non-porous collars were included in the study (n = 80). The mean age was 63.4 years (range 16-91 years); there were 37 males and 43 females. The groups showed no difference in implant survival (P = 0.54). The mean number of cortices with radiographic ongrowth for the porous bridging collar and non-porous collar groups was 2.1 and 0.3, respectively, at 6-month (P < 0.0001), 2.4 and 0.5, respectively, at 12-month (P = 0.044), and 3.2 and -0.2, respectively, at 24-month (P = 0.18) radiological follow-up.

CONCLUSION

These findings indicate that fully porous bridging collars increased the number of cortices, with evidence of bone ongrowth between 6 and 24 months post-implantation. By contrast, extra-osteal collars exhibited reduced evidence of ongrowth between 6 and 24 months post-implantation. In the medium term, the use of a fully porous bridging collar may translate to a reduced incidence of aseptic loosening.

Appearance and evolution of radiolucent lines below the tibial implant in primary total knee arthroplasty

BACKGROUND

The aim of this study was to evaluate total knee arthroplasty (TKA) radiographically to detect the occurrence of radiolucent lines (RLL) under the tibial base plate and to determine what type of RLL may have a correlation with aseptic loosening (AL). The study had two hypotheses: (1) RLLs may have different radiological aspects and evolutions in time depending of different factors (2) Signs of micro- and/or macro-mobility of the implant are necessary before diagnosing aseptic loosening of the tibial component.

METHODS

Retrospective cohort study of 774 patients operated with a Vanguard TKA (Zimmer Biomet, Warsaw, IN, US) from 2007 to 2015. RLLs were recorded in a database and described according to their radiological aspect, localization, time of apparition, progression and eventual evolution to AL. Other collected parameters were pre- and post-operative HKA angles, amount of post-operative HKA correction, surgical, clinical and demographic data.

RESULTS

178/774 TKAs (23%) showed RLLs under the tibial base plate including 9 (1.2%) tibial implants needing revision for AL. Three different types and two aspects of RLLs were observed. Important deformity corrections or undercorrected implants were recognized as a mechanical risk factor for loosening. Elderly women with osteoporosis and young men with important pre-operative deformities were identified as clinical risk factors for RLLs.

CONCLUSIONS

RLLs are frequently present at the epiphyseal bone/implant interface after total knee arthroplasty, but do not mean the implant is loose. They can be considered a sign of reduced epiphyseal surface fixation due to micro mobility of the tibial implant. Aseptic loosening can be observed radiologically when signs of macro-mobility of the implant are present at the metaphyseal level.

LEVEL OF EVIDENCE

III.

Femoral revision in total hip arthroplasty using a cementless modular stem: clinical and radiological results with a 8-year follow-up

INTRODUCTION

Modular femoral components allow for patient-specific restoration of hip joint geometry and the reconstruction of extensive bone defects in revision total hip arthroplasty (THA); however, potential problems of modular implants such as taper corrosion and the risk of implant fracture continue to be of concern. The aim of the present study was to evaluate the clinical and radiological results of a cementless modular revision stem following revision surgery due to aseptic loosening and periprosthetic fracture and to assess patient-reported outcome measures (PROMs) in these patients at mid-term follow-up.

MATERIALS AND METHODS

In this study, a consecutive cohort of 75 patients who underwent primary revision THA at our institution using a modular cementless stem design (MRP-TITAN stem) was retrospectively evaluated at a mean follow-up of 7.7 years. Kaplan-Meier survivorship analyses were performed with revision of the femoral component for any reason as the end point. The Harris-Hip Score, the UCLA Activity Score, the Forgotten Joint Score and the SF-12 Score were used for clinical assessment. We used the Wilcoxon signed rank test to compare pre- and postoperative clinical scores.

RESULTS

Overall stem survival with the endpoint stem re-revision for any reason was 85.4% at a mean follow-up of 7.7 years (range 2.4-14 years). Stem survival was 89.5% in the aseptic loosening group and 78.3% in the periprosthetic fracture group with no statistically significant difference between both groups (p = 0.107). One patient had to be revised due to taper fracture. PROMs improved significantly up to the latest follow-up, and radiographic evaluation showed full osseointegration of all stems in this cohort.

CONCLUSIONS

Revision THA using a modular cementless titanium revision stem demonstrated adequate clinical and radiological results at mid- to long-term follow-up in this cohort. Cementless revision stems are a useful treatment option to restore the anatomy, especially in deformed hips and in complex revision hip arthroplasty. However, there are some significant disadvantages related to an increased risk of mechanical failure such as corrosion/fretting damage and implant fracture. Future high-quality prospective studies with longer follow-up are necessary to confirm the supposed advantages.

Radiographic Cone Zone Classification of Metaphyseal Cone Fixation in Revision Total Knee Arthroplasty

Background

No objective radiographic scoring system exists to classify metaphyseal cone stability. Our purpose was to create a novel, systematic method to radiographically evaluate metaphyseal cone fixation based on radiographic findings suggestive of cone stability.

Methods

A retrospective analysis was conducted of revision total knee arthroplasty patients (6/2015-12/2017) using porous titanium femoral or tibial metaphyseal cones in conjunction with short cemented stems (50 mm-75 mm). Minimum follow-up was 2 years. Survivorship free of aseptic loosening and reoperation, as well as radiographic evaluation using a novel cone zone scoring system were analyzed.

Results

Forty-nine revision total knee arthroplasties were included in the study (12 femoral, 48 tibial cones), the majority, performed for aseptic loosening (25/49, 51%). Median follow-up was 39 months (range 25-58). Using the radiographic cone zone scoring method, >90% of all femoral cones were classified as likely stable or stable with strong, statistically significant intraclass correlations between all 3 reviewers. Similarly, >97% of all tibial cones were classified as likely stable or stable, with moderate, statistically significant intraclass correlations between all 3 reviewers. Only 1 femoral and 1 tibial cone were considered at risk of loosening. The study sample demonstrated 100% survivorship free of revision for aseptic loosening without evidence of radiographic loosening in any case.

Conclusions

Using a novel systematic cone zone scoring and classification method, the overwhelming majority of femoral and tibial cones were classified as likely stable or stable, with no identified cases of aseptic loosening or related revision. Further studies are needed to validate this objective classification method.

The impact of retaining the femoral stem in revision total hip arthroplasty: a systematic review, meta-analysis, and meta-regression

INTRODUCTION

The management of well-fixed femoral stems in revision total hip arthroplasty (rTHA) remains a subject of debate, with concerns over potential complications arising from stem retention. This study aimed to investigate the re-revision rates due to aseptic loosening of the stem, overall re-revision rates, dislocation rates, and factors influencing these outcomes in rTHA with a retained well-fixed femoral stem.

MATERIALS AND METHODS

A systematic search was conducted across several databases including PubMed, EMBASE, and CENTRAL to identify pertinent publications from their inception through 2023. We specifically focused on studies that reported outcomes of rTHA with retained well-fixed femoral stems. The study designs incorporated in our research encompassed both cohort studies and case series studies. Thirty-five studies involving isolated acetabular revision and retaining the stem were included, representing a total of 3497 patients. Data extraction was tailored to the study questions. Meta-analyses, meta-regression, and subgroup analyses were conducted to evaluate the outcomes and their relationship with various factors. Pooled results, meta-regression, and subgroup analyses were performed using random-effects models. To assess and reduce bias, we employed Egger's test and the trim and fill method.

RESULTS

The meta-analysis included 3497 patients with a mean follow-up of 9.28 years. The 10-year risk of re-revision after retaining femoral stem using highly cross-linked polyethylene was 1.7% (95% CI 1.1%-2.3%; I2: 60%) for stem aseptic loosening and 8.8% (95% CI 6.2%-11.4%; I2: 78%) overall re-revision. Dislocation risk was 5.7% (95% CI 4.1-7.0%; I2: 61%). Ceramic heads showed lower stem failure risk than metal heads in long-term follow-ups (P < 0.001). The posterolateral approach in revision surgery resulted in better long-term outcomes compared to the direct lateral approach (P < 0.001). Follow-up duration, timeline of study, Harris Hip Score, type of stem fixation, femoral head material, BMI, age, stem age, and surgical approach were evaluated as influential factors on these outcomes.

CONCLUSION

The re-revision rate due to aseptic loosening of the retained stem during rTHA was found to be significantly low, supporting the idea of retaining well-fixed stems during rTHA. The overall re-revision and dislocation rates also presented comparable or better outcomes to prior studies. A range of factors, including the use of highly cross-linked polyethylene and ceramic femoral heads, was found to influence these outcomes.

LEVEL OF EVIDENCE

IV.

PROSPERO REGISTRATION NUMBER

CRD42022351157.

Aseptic loosening around total joint replacement in humans is regulated by miR-1246 and miR-6089 via the Wnt signalling pathway

BACKGROUND

Total joint replacement for osteoarthritis is one of the most successful surgical procedures in modern medicine. However, aseptic loosening continues to be a leading cause of revision arthroplasty. The diagnosis of aseptic loosening remains a challenge as patients are often asymptomatic until the late stages. MicroRNA (miRNA) has been demonstrated to be a useful diagnostic tool and has been successfully used in the diagnosis of other diseases. We aimed to identify differentially expressed miRNA in the plasma of patients with aseptic loosening.

METHODS

Adult patients undergoing revision arthroplasty for aseptic loosening and age- and gender-matched controls were recruited. Samples of bone, tissue and blood were collected, and RNA sequencing was performed in 24 patients with aseptic loosening and 26 controls. Differentially expressed miRNA in plasma was matched to differentially expressed mRNA in periprosthetic bone and tissue. Western blot was used to validate protein expression.

RESULTS

Seven miRNA was differentially expressed in the plasma of patients with osteolysis (logFC >|2|, adj-P < 0.05). Three thousand six hundred and eighty mRNA genes in bone and 427 mRNA genes in tissue samples of osteolysis patients were differentially expressed (logFC >|2|, adj-P < 0.05). Gene enrichment analysis and pathway analysis revealed two miRNA (miR-1246 and miR-6089) had multiple gene targets in the Wnt signalling pathway in the local bone and tissues which regulate bone metabolism.

CONCLUSION

These results suggest that aseptic loosening may be regulated by miR-1246 and miR-6089 via the Wnt signalling pathway.

Tibial implant design in primary TKA: retrospective comparison of two designs for the occurrence of radiolucent lines and aseptic loosening

INTRODUCTION

The purpose of this retrospective study was to study the effect of tibial implant design on the occurrence of radiolucent lines (RLLs) and aseptic loosening (AL) by comparing two different total knee arthroplasty (TKA) designs.

MATERIALS AND METHODS

Two types of total knee arthroplasty, different for tibial shape, size and keel design were compared, 255 for the first and 774 for the second. The occurrence of RLLs and radiological signs of micro- and macro-mobility and aseptic loosening was analyzed. Demographic data were compared, as well as the type and rate of RLLs, occurrence of aseptic loosening and the presence of potential risk factors.

RESULTS

The first implant design is morphometric and has a squarer keel than the second implant TKA. The overall rate of RLLs was similar (21% vs 23%), despite of a significantly lower rates of radiological signs of macro-mobility of the tibial component with the first implant (2% vs 17%). Survivorship of both designs was overall comparable (99.6% vs 98.8 %) the first implant group had more potential risk factors for poor bone quality than the second group (p < 0.05).

CONCLUSION

A morphometric design is more anatomic and offers better bone coverage of the epiphyseal tibial surface. RLLs, as a sign of implant micro-mobility, were equally present in both designs. Radiological signs of macro-mobility at the metaphysis were less frequently observed in squared keel design. The morphometric implant did not show improved survivorship compared with a symmetric implant.

LEVEL OF EVIDENCE

III.

Tourniquet-free minimally invasive total knee arthroplasty is associated with early aseptic loosening

BACKGROUND

While tourniquet-free (T-) total knee arthroplasty (TKA) has gained popularity, tourniquet-use during minimally-invasive (MIS)-TKA has not been adequately studied. Traditional techniques employ knee hyper-flexion, compressing vasculature and reducing impact of bleeding, while MIS-TKA embraces the semi-extended knee position, which does not restrict the effects of bleeding on cementation and visualization. We compared the risk of aseptic loosening between patients undergoing T- MIS-TKA compared to T + MIS-TKA.

METHODS

This single-surgeon cohort study included 329 consecutive MIS-TKA (226 T+,103 T-) patients with minimum 3-year follow-up. Aseptic loosening, radiolucent lines (RLL), health related quality of life scores, and complications were recorded. T-test and chi-square test were used to compare continuous and categorical variables, and logistic regression included BMI, age, ASA, patellar-resurfacing, and tourniquet-use.

RESULTS

There were no differences in baseline demographics. One (0.4 %) aseptic loosening occurred with T+, versus 7 (6.8 %) with T- (p = 0.002). No T + and 3 T- patients (2.9 %, p = 0.01) had revision for aseptic loosening. The incidence of RLLs was 16.8 % in T + and 30.1 % in T- (p = 0.008). Logistic regression revealed T + was significantly associated with decreased aseptic loosening and risk of RLL (odds ratio = 16.4, odds ratio = 2.8).

CONCLUSION

In this consecutive series, T- MIS-TKA was associated with increased rates of revision for aseptic loosening as compared to the T + MIS-TKA, even controlling for BMI, age, ASA level, and patellar resurfacing. Radiolucent lines were increased with T- MIS-TKA compared to T + MIS-TKA. Complications, all-cause revision, ROM, and HRQoL scores were similar between tourniquet-use and tourniquet-free cohorts.

Revision of total ankle arthroplasty: Survival and medium-term functional results

BACKGROUND

The objective of this study was to analyze the results and survivorship of total ankle arthroplasty (TAA) revision surgery with standard (Salto Talaris®) or revision (Salto Talaris XT®) implants.

METHODS

Between January 2005 and December 2017, all patients undergoing TAA revision at our hospital were included. Indications for revision, type of surgery performed, improvement in function assessed with the AOFAS score, occurrence of complications and implant survival at last follow-up were analyzed.

RESULTS

In the end, 25 TAA patients who had undergone revision (11 unipolar, 14 bipolar) were included. The mean follow-up time was 5.1 ± 1.9 years. At the last follow-up, function was improved compared to the preoperative AOFAS score (51.3 ± 17.5 vs. 83.5 ± 10.1; p < .001), but not plantar flexion (17.5 ± 5.7 vs. 15.4 ± 7.1; p = 0.28) or dorsal flexion (7 ± 5.6 vs. 8.3 ± 4.9; p = 0.3). Complications occurred in six patients (24 %) that led to reoperation: three infections, one lateral impingement, one implant malposition, and one hindfoot alignment disorder. At the last follow-up, implant survival was 96 %, but the probability of survival without reoperation was 78.7 ± 8.5 % at 4 years.

CONCLUSION

TAA revision by arthroplasty is feasible, produces good functional results in the medium term, but has a high risk of complications. The challenge of revision TAA is managing the loss of bone stock and anchoring the new implants.

Patient mortality after total hip arthroplasty revision surgery

Background

Complications following revision total hip arthroplasty can cause significant morbidity and have a high mortality rate. Patient age and American Society of Anaesthesiologists (ASA) physical status classification system score are important determinants of mortality following revision hip arthroplasty. There is a paucity of high-quality evidence assessing the risk of mortality following revision hip arthroplasty stratified by indications of surgery. The aim of this study is to compare survival of patients undergoing revision THA for different indications.

Methods

This retrospective case series reviewed the mortality rate following revision hip surgery performed by a single surgeon between 2009 and 2016 with a minimum 2 year follow up. Kaplan Meir analysis was performed using mortality as the end point. Log rank testing was used to determine if the indication for surgery conferred a difference in survival.

Results

One hundred and ninety-eight consecutive cases were done using a tapered modular uncemented stem in 183 patients and were followed up for a mean period of 51.8 months (range, 24-121). Sixty patients died (67 % survivorship) during the follow up period with a 5-year survival rate of 78 %. Revision surgery performed for aseptic loosening had the best survival and hemiarthroplasty had the worst and differences in survival were statistically significant (P = 0.000002).

Conclusion

The indication for revision surgery is an important criterion which must be given weightage along with age, functional status of patient and ASA physical status score while planning revision surgery and counselling patients.

Inflammatory bowel disease patients undergoing total hip arthroplasty have higher odds of implant-related complications

PURPOSE

This study evaluates whether IBD patients are at increased risk of implant-related complications after THA.

MATERIALS AND METHODS

A retrospective study from 01 January 2010 to 31 October 31 2020 using an administrative claims database was performed. IBD patients undergoing THA (n = 11,025), without corticosteroid treatment, were propensity score matched to controls in a 1:5 ratio (n = 55,121) based on age, sex, and the Charlson Comorbidity Index (CCI). Outcomes evaluated included periprosthetic fracture, aseptic loosening, prosthetic joint infection, and THA revision within 2 years of index procedure. Chi-square analyses were used to compare the matched cohorts. The association of IBD and implant-related complications was evaluated using logistical regression to calculate odds ratios (ORs), 95% confidence intervals (95% CIs), and p-values. A p-value < 0.001 was used as the significance threshold.

RESULTS

Patients with IBD had a greater incidence and odds of total implant complications (7.03% vs. 3.98%; OR 1.76; p < 0.001) compared with matched controls. IBD patients had significantly higher incidence and odds of developing periprosthetic fracture (0.50% vs. 0.20%; OR 2.46; p < 0.001), THA revisions (2.21% vs. 1.17%; OR 1.91; p < 0.001), aseptic loosening (1.45% vs. 0.84%; OR 1.75; p < 0.001), and prosthetic joint infection (2.87% vs. 1.77%; OR 1.64; p < 0.001).

CONCLUSIONS

Patients with IBD who underwent primary THA had a significantly higher risk of implant-related complications compared to matched controls. Providers should use this study to appropriately assess post-complication risk factors for their patients with IBD.

Cementing techniques for total knee arthroplasty in Norwegian hospitals; a questionnaire-based study

BACKGROUND

Cementing technique in total knee arthroplasty (TKA) may influence implant survival. There is limited knowledge about the results with clinically used techniques. The aim of this study was to investigate cementing techniques for TKA in Norwegian hospitals, to compare widely used techniques to recommendations from the literature, and to investigate variation within hospitals.

METHODS

A questionnaire requesting information about cementing techniques were distributed to all Norwegian orthopedic surgeons performing TKAs regularly in 2020. Data was analyzed using descriptive statistical methods.

RESULTS

We acquired 121 responses out of 257 surgeons. They were from 45 out of 56 hospitals, and at least half of the TKA surgeons from 20 hospitals, constituting 79 surgeons. All responders used pulsatile lavage. Cement application to both the tibial plateau and stem (full cementation) was practiced by 61%. Application of cement to both implant and bone was done by 70% of surgeons. Techniques to improve cement penetration were used by 86%. Only 35% of surgeons aimed to get a cement mantle thickness between 3-5 mm. Flexing the knee joint to remove excess cement was done by 82%. We found that in 55% of 20 hospitals the surgeons did not agree on the use of common guidelines in their ward.

CONCLUSIONS

The majority of the responders used recommended techniques from the literature when cementing TKA. At more than half of the eligible hospitals, surgeons disagreed about their hospitals' use of common guidelines. Focusing on developing evidence-based guidelines would be beneficial for TKA-quality.

Single-taper conical tapered stem in total hip arthroplasty for developmental dysplasia of the hip: A long-term evaluation

INTRODUCTION

Conical tapered stems may be useful implants to manage the reconstruction of complex dysplastic anatomies. The aims of this paper were to assess: 1) the preoperative CT features of the dysplastic femurs; 2) survival rates, complications and reasons for revision; 3) the clinical outcomes; 4) the radiographic outcomes of single-taper conical stems in dysplasia (defined as center edge angle < 20°) at a long-term follow-up.

HYPOTHESIS

Monoblock conical stem provides a 10-year survival rate of at least 95%, with excellent clinical outcomes and bony ingrowth.

MATERIALS AND METHODS

In total, 100 THAs in 85 patients (15 bilateral cases) were enrolled. The average age of the patients at surgery was 50.9±11.5 years. Assessment of the native femoral morphology was performed using CT-scan, coronal (neck-shaft angle, offset, center of rotation position) and axial parameters (anteversion, mediolateral and anteroposterior femoral diameters). Clinical (HHS score) and radiological (osseointegration, subsidence and offset reconstruction) outcomes were evaluated at the last available follow-up.

RESULTS

The mean follow-up was 9.34±5.61 years. Severely distorted anatomies from Crowe I to Crowe IV were included, with a mean canal flare of 4.3 and a mean femoral antetorsion of 34°. The survival rates were stable at long-term (98.9% at 10 and 15 years): no aseptic loosening occurred. The mean postoperative HHS was 89.8±6.8 points. Ninety-nine percent of the stems showed bone ingrowth, from 6 months to the last available follow-up. Subsidence occurred in 18% of the cases (mean value: 2.5mm, range: 1-6mm) in the first month, with subsequent stabilization. A mild proximal stress shielding occurred in 28% of the THAs. Radiolucent lines were detected in the 8% of the cases. There was a postoperative loss of offset in 12% of the cases.

DISCUSSION

Conical stems in dysplastic hips achieved bony ingrowth at long-term outcome, even in complex anatomies. Subsidence, proximal stress shielding and imperfect offset restoration may occur with this implant.

LEVEL OF PROOF

IV; retrospective study.

Computer-aided Design and 3D-printed Personalized Stem-plate Composite for Precision Revision of the Proximal Humerus Endoprosthetic Replacement: A Technique Note

BACKGROUND

Aseptic loosening is considered to be a rather uncommon complication in proximal humerus endoprosthetic replacement (PHER). However, patients with aseptic loosening often suffer severe bone loss, which poses a great challenge in following revision. Under this situation, a standard stemmed endoprosthesis is unavailable for revision limb salvage. Computer-aided design and 3D-printed personalized implants are an emerging solution for reconstructing complex bone defects.

CASE PRESENTATION

Here, we present a 67-year-old male who underwent PHER after tumor resection and developed aseptic loosening with severe periprosthetic osteolysis around the stem. Computer-aided design and 3D-printed personalized stem-plate composite was used for the precision revision of this patient. During the follow-up, encouraging results were observed, with good endoprosthetic stability and satisfactory limb function.

CONCLUSION

Computer-aid design and 3D-printed personalized stem-plate composite used in the present case could help to achieve good endoprosthetic stability and satisfactory limb function. This 3D-printed personalized stem-plate composite seems to be an effective method for the precise revision of PHER in patients with severe periprosthetic osteolysis. In addition, it also provides a novel method for similar revision surgery of other joints or primary endoprosthetic replacement with severe bone defects.

Does lucency equate to revision? A five-year retrospective review of Attune and Triathlon total knee arthroplasty

PURPOSE

The Attune® total knee arthroplasty system was introduced in 2013 to address lingering issues of patient dissatisfaction. However, recent literature reports concerns of early tibial tray debonding. The aim of this study was to compare the incidence of radiolucent lines, survivorship and patient reported outcome-measures between the Attune® system and the well-established Triathlon® system.

METHODS

This retrospective database review was conducted at a single institution in Cork, Ireland. All primary Attune® (N = 445) and Triathlon® (N = 285) systems implanted between 2015 and 2016 were reviewed. Radiolucent lines were assessed for those with a minimum two-year radiological follow-up (Attune® = 338; Triathlon® = 231). X-rays were taken post op, at 6 months, 2 years and 5 years. Radiolucent lines were documented using the Modern Knee Society Radiographic System. Five-year survival was assessed using Kaplan-Meier analysis with the Log Rank method to determine statistical significance. The Oxford Knee Score and EQ-5D-5L, were collected pre-op, at 6 months, 2 years and 5 years post-operatively and compared using the Kruskal-Wallis Test.

RESULTS

The Attune® had a higher proportion of radiolucent lines at the tibial tray [87.1% (54/62) vs 61.4% (27/44); p = 0.001] and at the implant-cement interface [62.9% (39/62) vs 43.2% (19/44); p = 0.02]. Conversely, the Triathlon® had a higher proportion AT the femur [38.6% (17/44) vs 12.9% (8/62); p = 0.001] and at the cement-bone interface [56.8% (25/44) vs 37.1% (23/62); p = 0.02]. The overall frequency of radiolucent lines was similar in both the Attune® and Triathlon® groups [17.8%, (60/338) vs 17.7%, (41/231); p = 0.49]. There was no difference in revision-free survival analysis at 5 years (Attune® 97.8% vs Triathlon® 95.8%; p = 0.129). The Attune® performed better at 5 years in the Oxford Knee Score [Attune® = 42.6 (SD 5.2) vs Triathlon® = 41 (SD 6.4); p = 0.001] and in the EQ-5D [Attune® = 0.773 (SD 0.187) vs Triathlon® = 0.729 (SD 0.218); p = 0.013]. There was no difference at 5 years in the EQ-VAS [Attune® = 80.4 (SD 13.7) vs Triathlon® = 78.5 (SD 15.3); p = 0.25].

CONCLUSION

The Attune® system exhibited a higher incidence of  radiolucent lines at the tibial tray. However, this did not lead to decreased survivorship at medium term follow-up compared to the Triathlon®. Furthermore, improvements in patient reported outcomes modestly favoured the Attune® system.

LEVEL OF EVIDENCE

III.

Is the Citak classification of distal femur morphology age and gender dependent?

INTRODUCTION

The purpose of this study was to compare the distal femur morphology in different age and gender groups using the Citak classification.

MATERIALS AND METHODS

All patients who had standard knee anteroposterior radiographs between 2010 and 2020 were retrospectively reviewed using the electronic patient database. Patients were divided into three age groups as follows: young adults (Group I, younger than 50 years), middle-aged adults (Group II, ranging from age 51 to 73 years), and elderly (Group III, more than 74 years). From each age group, 80 patients were randomly selected with an equal number of gender (40 males/40 females). An age-stratified selection was applied to obtain the best sample that represents the selected age groups. Patients younger than 18 years of age, history of previous fracture or surgical procedure, those with fixation implants or prosthesis, and abnormalities of the lower limb, such as a congenital deformity, were excluded from the study. All measurements were performed by an experienced orthopedic surgeon familiar with the Citak classification. All measured variables were compared between age and gender groups.

RESULTS

There were 240 patients (120 male and 120 female) with a mean age of 59.6 ± 20.4 (range 18-95). The distal femur morphology index was similar (p:0.811), and the morphological types were equally distributed among age groups (p:0.819). Furthermore, there was no significant difference between genders on the measured variables (p > 0.05 for all variables). Citak classification types were similarly distributed between the genders (p:0.153). No correlation was found between age and the Citak index in either gender (p:0.967 and p:0.633, respectively).

CONCLUSIONS

Distal femoral morphology classified by the Citak index is not age and gender dependent. Type C, which has a wider diaphyseal diameter, and is supposed to be more common in elderly subjects, was equally distributed in all age groups.

LEVEL OF EVIDENCE

Level IV. Retrospective case series.

PLGA nanoparticles engineering extracellular vesicles from human umbilical cord mesenchymal stem cells ameliorates polyethylene particles induced periprosthetic osteolysis

The wear particle-induced dissolution of bone around implants is a significant pathological factor in aseptic loosening, and controlling prosthetic aseptic loosening holds crucial social significance. While human umbilical cord mesenchymal stem cell-derived exosomes (HucMSCs-Exos, Exos) have been found to effectively promote osteogenesis and angiogenesis, their role in periprosthetic osteolysis remains unexplored. To enhance their in vivo application, we engineered HucMSCs-Exos-encapsulated poly lactic-co-glycolic acid (PLGA) nanoparticles (PLGA-Exos). In our study, we demonstrate that PLGA-Exos stimulate osteogenic differentiation while inhibiting the generation of reactive oxygen species (ROS) and subsequent osteoclast differentiation in vitro. In vivo imaging revealed that PLGA-Exos released exosomes slowly and maintained a therapeutic concentration. Our in vivo experiments demonstrated that PLGA-Exos effectively suppressed osteolysis induced by polyethylene particles. These findings suggest that PLGA-Exos hold potential as a therapeutic approach for the prevention and treatment of periprosthetic osteolysis. Furthermore, they provide novel insights for the clinical management of osteolysis.

What is the rate of successful closed reduction of dislocated dual mobility cups following complex revision hip arthroplasty?

PURPOSE

The aim of this study was to assess the difference in success rates of closed reduction in septic and aseptic revision total hip arthroplasty (THA) performed with a dual mobility (DM) implant. Our objective was to answer the following questions: (1) Is there a difference in success rates of closed reduction between septic and aseptic revision THA with a DM implant? (2) Is closed or open reduction more successful in preventing re-dislocation?

METHODS

Between January 2009 and October 2021, 924 revisions were performed with a DM implant. All patients presenting to our institution with a dislocation following septic or aseptic revision THA using a cemented DM cup were included in this study. We analyzed 106 cases of dislocation in 74 patients. For all patients, we collected reason for revision, and classified index surgery as septic or aseptic.

RESULTS

Overall, 106 dislocations occurred (106/924, 11.5%). Thirty-nine cases (52.7%) had a dislocation after a septic exchange THA, while in 35 patients (47.3%), a dislocation occurred after an aseptic rTHA. In 29 patients (39.2%), successful closed reduction under general anesthesia was feasible, while the majority of cases required open reduction. In 31 of these patients (67.4%), open reduction was combined with a revision arthroplasty.

CONCLUSIONS

In case of DM cup dislocation, there is a low success rate of closed reduction. To prevent re-dislocation, total revision leads to a significantly reduced risk compared to open or closed reduction alone. Careful X-ray analysis for a halo sign showing intra-prosthetic DM cup dislocation is mandatory to avoid futile reduction attempts.

LEVEL OF EVIDENCE

III.

Particle-induced osteolysis is mediated by endoplasmic reticulum stress-associated osteoblast apoptosis

Osteoblast dysfunction plays a crucial role in periprosthetic osteolysis and aseptic loosening, and endoplasmic reticulum (ER) stress is recognized as an important causal factor of wear particle-induced osteolysis. However, the influence of ER stress on osteoblast activity during osteolysis and its underlying mechanisms remain elusive. This study aims to investigate whether ER stress is involved in the detrimental effects of wear particles on osteoblasts. Through our investigation, we observed elevated expression levels of ER stress and apoptosis markers in particle-stimulated bone specimens and osteoblasts. To probe further, we employed the ER stress inhibitor, 4-PBA, to treat particle-stimulated osteoblasts. The results revealed that 4-PBA effectively alleviated particle-induced osteoblast apoptosis and mitigated osteogenic reduction. Furthermore, our study revealed that wear particle-induced ER stress in osteoblasts coincided with mitochondrial damage, calcium overload, and oxidative stress, all of which were effectively alleviated by 4-PBA treatment. Encouragingly, 4-PBA administration also improved bone formation and attenuated osteolysis in a mouse calvarial model. In conclusion, our results demonstrate that ER stress plays a crucial role in mediating wear particle-induced osteoblast apoptosis and impaired osteogenic function. These findings underscore the critical involvement of ER stress in wear particle-induced osteolysis and highlight ER stress as a potential therapeutic target for ameliorating wear particle-induced osteogenic reduction and bone destruction.

Titanium modular stems in total hip arthroplasty due to developmental dysplasia: a registry comparison with single-taper implants

INTRODUCTION

The routine use of proximal femoral modularity was discouraged in total hip arthroplasties (THAs). However, titanium dual-taper (DT) implants may provide some advantages over single-taper (ST) stems in cases of complex deformity. A registry study comparing ST and DT stems in dysplasia was designed, aiming to assess: (1) survival rates at long-term; (2) reasons for revision; (3) the profile of failed implants.

METHODS

The arthroplasty registry RIPO was investigated for cementless THAs performed for dysplasia since 2000. ST implants were compared to titanium-on-titanium DT stems. Demographics and implant features were collected. Survival rates and reasons for revision were compared. The profile of DT stem failures in dysplasia was defined.

RESULTS

6429 implants were included in the study, 3642 ST and 2787 DT. The demographic and implant features of the 2 cohorts were not comparable. The DT cohort achieved higher survival rates at long-term (93.9% vs. 91.6%, p = 0.018). DT implants showed a higher rate of implant breakage (0.6%, p = 0.011) and a lower rate of aseptic loosening (p = 0.005). There were no differences in terms of revisions for dislocation. No metallosis occurred. There were more revisions in DT implants in males <65 years, with a 28-mm head size or smaller.

CONCLUSIONS

Modularity did not result in lower survival rates in dysplastic patients and may even reduce the rate of aseptic loosening in comparison to ST stems. The rate of implant breakage is not negligible. Younger males are not good candidates for titanium DT stems.

CD73 inhibits titanium particle-associated aseptic loosening by alternating activation of macrophages

Aseptic inflammation is a major cause of late failure in total joint arthroplasty, and the primary factor contributing to the development and perpetuation of aseptic inflammation is classical macrophage activation (M1 phenotype polarization) induced by wear particles. CD73 (ecto-5'-nucleotidase) is an immunosuppressive factor that establishes an adenosine-induced anti-inflammatory environment. Although CD73 has been shown to suppress inflammation by promoting alternate macrophage activation (M2 phenotype polarization), its role in wear particle-induced aseptic inflammation is currently unknown. Our experiments were based on metabolomic assay results in a mouse model of aseptic loosening, and studied the function of CD73 in vivo and in vitro using a mouse aseptic loosening model and a mouse bone marrow derived macrophage (BMDM) inflammation model. Results show that aseptic loosening (AL) reduces the purine metabolic pathway and decreases the native expression of the metabolite adenosine. In vivo, CD73 expression was low in the bone tissue surrounding the titanium nail and synovial-like interface tissue, while in vitro experiments demonstrated that CD73 knockdown promoted titanium particles-induced aseptic inflammation. CD73 overexpression mitigated the titanium particle-mediated enhancement of LPS-induced M1 polarization while promoting the titanium particle-mediated attenuation of IL-4-induced M2 polarization. In BMDM exposed to titanium particles, CD73 promotes M2 polarization via the p38 pathway. Meanwhile, local injection of recombinant mouse CD73 protein slightly alleviated the progression of AL. Collectively, our data suggest that CD73 alleviates the process of AL, and this function is achieved by promoting alternate activation of macrophages.

Beyond type III Paprosky acetabular defects: are partial pelvic replacements with iliosacral fixation successful?

PURPOSE

Supra-acetabular bone loss close beyond the sciatic notch is one of the most challenging defect types for stable anatomical reconstruction in revision arthroplasty. Using reconstruction strategies from tumour orthopaedic surgery, we adapted tricortical trans-iliosacral fixation options for custom-made implants in revision arthroplasty. The aim of the present study was to present the clinical and radiological results of this extraordinary pelvic defect reconstruction.

METHODS

Between 2016 and 2021, 10 patients with a custom-made pelvic construct using tricortical iliosacral fixation (see Fig. 1) were included in the study. Follow-up was 34 (SD 10; range 15-49) months. Postoperatively CT scans evaluating the implant position were performed. Functional outcome and the clinical results were recorded.

RESULTS

Implantation was possible as planned in all cases in 236 (SD 64: range 170-378) min. Correct centre of rotation (COR) reconstruction was possible in nine cases. One sacrum screw crossed a neuroforamen in one case without clinical symptoms. During the follow-up period, four further operations were required in two patients. There were no individual implant revisions or aseptic loosening recorded. The Harris Hip Score increased significantly from 27 Pts. to 67 Pts. with a mean improvement of 37 (p < 0.005). EQ-5D developed from 0.562 to 0.725 (p = 0.038) as a clear improvement in quality of life.

CONCLUSION

Custom-made partial pelvis replacement with iliosacral fixation offers a safe solution in "beyond Paprosky type III defects" for hip revision arthroplasty. Due to meticulous planning, precise implantation with good clinical outcome can be achieved. Furthermore, the functional outcome and patient satisfaction increased significantly showing promising early results with a relatively low complication rate.

Revision Distal Femoral Replacement Using Custom-made Stem and Cone to Augment Proximal Fixation

Achieving bone fixation during megaprosthesis revision presents a formidable challenge in view of the substantial bone loss. We report treatment of a failed revision distal femoral replacement in an active 36-year-old male mechanic remotely treated for osteosarcoma. A custom stem and cone were manufactured to augment fixation and preserve bone stock within a short segment of the remaining proximal femur. The patient returned to regular function without the need for assistive devices. Follow-up imaging demonstrated stable implant fixation at 1-year follow-up. While cones and sleeves have vastly improved fixation in revision knee arthroplasty, a custom-made cone for the proximal femur was used to augment fixation of a revision megaprosthesis and obviate the use of a total femoral replacement.

Outcomes in revision knee arthroplasty: Preventing reoperation for infection Keynote lecture - BASK annual congress 2023

Revision total knee arthroplasty (TKA) patients have a lower survival rate and lower post-surgical outcomes compared to primary TKA patients. Infection and aseptic loosening are the most common reasons for revision and re-revision TKAs, with infection accounting for nearly half of re-revision cases. To prevent infection, patient optimization addressing obesity, diabetes, malnutrition, and smoking cessation is crucial. Advancements in irrigation solutions, antibiotic-impregnated bone fillers, bacteriophage therapy, and electrochemical therapy hold promise for preventing infection. Technical strategies such as obtaining sufficient component fixation, joint line restoration, and using robot assistance may improve revision TKA outcomes. As the burden of revision TKA continues to rise, substantial efforts remain for mitigating future revision TKAs and their associated complications.

Review of bone deficiency in total elbow arthroplasty revision

Total elbow arthroplasty revision rates have been increasing over time due to the increasing use of the procedure with the accompanying increase in complications. The most common complications that typically require revision surgery include aseptic loosening, periprosthetic fractures, infection, and component failure. The associated instability has an overall revision rate reported to be as high as 13%. One important factor when performing a revision surgery is bone quality and bone loss; this represents a challenge during the clinical decision-making process. Currently, there are several strategies used to address bone loss such as arthrodesis, resection arthroplasty, impaction grafting, allograft-prosthetic composite reconstruction, and custom prostheses. The aim of this review article is to provide a comprehensive review of the current strategies to improve diagnosis of failed total elbow arthroplasty and improve management and outcomes of this patient population.

Three-dimensional design custom-made uncemented stem for revision of cemented distal femoral endoprosthesis due to aseptic loosening

BACKGROUND

Revision of cemented distal femoral replacement (DFR) due to aseptic loosening is challenging because of the resultant femoral bone loss. This paper aims to examine the outcomes of three-dimensional (3D) design custom-made uncemented stems for revision.

METHODS

Between January 2014 and December 2020, 17 patients received 3D design uncemented stems for revision of loosed cemented DFR. The femoral bone loss was classified into four Grades, and four types of uncemented stems were designed correspondingly. The revision stems were custom-made for each patient by measuring the diameter of the medullary cavity and the anterior curvature of the femur.

RESULTS

The patient counts with their corresponding Grades of femoral bone loss were as follows: Grade I, 8 patients; Grade II, 5 patients; Grade III, 3 patients; and Grade IV, 1 patient. During the mean follow-up of 80 months, no revision failure was detected. The postoperative radiographic showed that the stem matched the femoral anterior curvature well. The femoral bone defect was completely filled by the 3D design stem in 10 of the 17 cases postoperatively. In the remaining cases, the persistent peri-stem defect was filled or partially restored during the follow-up.

CONCLUSION

3D design custom-made uncemented stem created precise, stable, and durable fixation and provided satisfactory clinical outcomes, which seems to be a viable method for cemented DFR revision.

HMGB-1 Levels in Painful Knee Arthroplasty: Is it Possible to Distingue Periprosthetic Joint Infection and Aseptic Loosening?

Introduction

We investigated the efficiency of high mobility group box-1 protein (HMGB-1) in differentiation of asymptomatic knee prosthesis, and periprosthetic joint infection and aseptic loosening causing painful knee prosthesis.

Materials and Methods

The data of patients who consulted our clinic for checking after total knee arthroplasty surgery were recorded prospectively. Blood levels of CRP, ESR, WBC, and HMGB-1 were recorded. Patients whose examination and routine tests were within normal limits comprised group I, asymptomatic total knee arthroplasty (ATKA). Painful patients with abnormal test results underwent three phase bone scintigraphy for further investigation Patients with periprosthetic joint infection (PJI) and aseptic loosening (AL) according to scintigraphy comprised group II and group III, respectively. The mean values of HMGB-1 and cut-off values according to the groups and their correlations with other inflammatory parameters were determined.

Results

Seventy-three patients were included in the study. Significant differences were observed in three groups, in terms of CRP, ESR, WBC, and HMGB-1. The cut-off value of HMGB-1 was determined as 15.16 ng/ml between ATKA and PJI, 16.92 ng/ml between ATKA and AL, and 27.87 ng/ml between PJI and AL, respectively. Accordingly, the sensitivity, and specificity of HMGB-1 in differentiation of ATKA and PJI were 91%, 88%, and in differentiation of ATKA and AL were 91%, 96%, and in differentiation of PJI and AL were 81%, 73%, respectively.

Conclusion

HMGB-1 may be utilized as an additional blood test in the differential diagnosis of problematic knee prosthesis patients.

Aseptic loosening of tumor prostheses in distal femur after revision surgery: a retrospective study

BACKGROUND

Tumor prostheses of the distal femur after revision surgery is associated with high rates of aseptic loosening, which has introduced great challenges to the survival of patients, but only a few studies have evaluated their X-ray imaging. The purpose of this study was to analyze the risk factors for recurrence of aseptic loosening and make recommendations to reduce the incidence of aseptic loosening after revision surgery of tumor prostheses in the distal femur.

METHOD

A retrospective analysis was performed on 23 patients who had revision surgery for distal femur prostheses due to aseptic loosening between June 2002 and June 2021. They were divided into two groups based on the condition of the prostheses after revision surgery: loosening group (9 patients) and control group (14 patients). Following the initial replacement, the length and diameter of the prosthetic intramedullary stem were measured through the standard full-length anteroposterior X-ray imaging of both lower limbs. The osteotomy length, femoral length and diameter, femoral intramedullary stem diameter, hip-knee-ankle angle (HKAA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and so on were measured as well. Following that, statistical analysis was performed.

RESULTS

Patients in the loosening group had statistically significant differences in the ratio of prostheses length to femur length (71.89 ± 6.62) and the ratio of intramedullary stem diameter to femoral diameter (25.50 ± 6.90) (P < 0.05), when compared to the control group. The HKAA (175.58 ± 2.78), mLDFA (94.42 ± 2.57), and the deviation angle between the lower limb alignment and the tibial prostheses force line (2.23 ± 1.09) in the loosening group were significantly different from those in the control group (P < 0.05) on postoperative radiographs of the entire length of the lower limbs. The lowest score in intramedullary manubrium I indicated less osteolysis, while the highest score in intramedullary manubrium III indicated the most serious osteolysis, and the difference was statistically significant (P < 0.05).

CONCLUSIONS

Our study suggests that the use of longer and thicker intramedullary stems can effectively decrease the occurrence of aseptic loosening. Additionally, it is important to avoid using the original prostheses and reconstruct the standard line of lower limb force to further reduce the incidence of aseptic loosening. It is crucial to closely monitor the distal segment of the intramedullary stem for osteolysis after surgery.

Clinical outcomes of various types of revision surgeries after unicompartmental knee arthroplasty failure

PURPOSE

The advantages of unicompartmental knee arthroplasty (UKA) have led to the procedure being increasingly performed worldwide. However, revision surgery is required after UKA failure. According to the literature review, the choice of implant in revision surgery remains a debatable concern. This study analyzed the clinical results of different types of prostheses used in treating failed UKA.

MATERIALS AND METHODS

This is a retrospective review of 33 failed medial UKAs between 2006 and 2017. Demographic data, failure reason, types of revision prostheses, and the severity of bone defects were analyzed. The patients were classified into three groups: primary prosthesis, primary prosthesis with a tibial stem, and revision prosthesis. The implant survival rate and medical cost of the procedures were compared.

RESULTS

A total of 17 primary prostheses, 7 primary prostheses with tibial stems, and 9 revision prostheses were used. After a mean follow-up of 30.8 months, the survival outcomes of the three groups were 88.2%, 100%, and 88.9%, respectively (P = 0.640). The common bone defect in tibia site is Anderson Orthopedic Research Institute [AORI] grade 1 and 2a (16 versus 17). In patients with tibial bone defects AORI grade 2a, the failure rates of primary prostheses and primary prostheses with tibial stems were 25% and 0%, respectively.

CONCLUSIONS

The most common cause for UKA failure was aseptic loosening. The adoption of a standardized surgical technique makes it easier to perform revision surgeries. Primary prostheses with tibial stems provided higher stability, leading to a lower failure rate due to less risk of aseptic loosening in patients with tibial AORI grade 2a. In our experience, we advise surgeons may try using primary prostheses in patients with tibial AORI grade 1 and primary prostheses with tibial stems in patients with tibial AORI grade 2a.

Total knee arthroplasty in patients with severe obesity: outcomes of standard keeled tibial components versus stemmed universal base plates

BACKGROUND

Patients with severe obesity [body mass index (BMI) ≥ 40 kg/m²] potentially overload the tibial component after total knee arthroplasty (TKA), risking tibial subsidence. Using a cemented single-radius cruciate-retaining TKA design, this study compared the outcomes of two tibial baseplate geometries in patients with BMI ≥ 40 kg/m²: standard keeled (SK) or universal base plate (UBP), which incorporates a stem.

METHODS

This was a retrospective, single-centre cohort study with minimum 2 years follow-up of 111 TKA patients with BMI ≥ 40 kg/m²: mean age 62.2 ± 8.0 (44-87) years, mean BMI 44.3 ± 4.6 (40-65.7) kg/m² and 82 (73.9%) females. Perioperative complications, reoperations, alignment and patient-reported outcomes (PROMS): EQ-5D, Oxford Knee Score (OKS), Visual Analogue Scale (VAS) pain score and satisfaction were collected preoperatively, and at 1 year and final follow-up postoperatively.

RESULTS

Mean follow-up was 4.9 years. SK tibial baseplates were performed in 57 and UBP in 54. There were no significant differences in baseline patient characteristics, post-operative alignment, post-operative PROMs, reoperations or revisions between the groups. Three early failures requiring revision occurred: two septic failures in the UBP group and one early tibial loosening in the SK group. Five-year Kaplan-Meier survival for the endpoint mechanical tibial failure was SK 98.1 [94.4-100 95% confidence interval (CI)] and UBP 100% (p = 0.391). Overall varus alignment of the limb (p = 0.005) or the tibial component (p = 0.031) was significantly associated with revision and return to theatre.

CONCLUSIONS

At early to mid-term follow-up, no significant differences in outcomes were found between standard and UBP tibial components in patients with BMI ≥ 40 kg/m². Varus alignment of either tibial component or the limb was associated with revision and return to theatre.

Diabetes mellitus is a potential risk factor for aseptic loosening around hip and knee arthroplasty

BACKGROUND

Aseptic loosening is a leading cause of revision following total hip and knee arthroplasty which is caused by chronic inflammation around the prosthesis. Diabetes mellitus causes systemic inflammatory changes which could increase the risk of aseptic loosening. This study investigated the association between diabetes mellitus and aseptic loosening around hip and knee arthroplasty.

METHODS

A case-control study was conducted at a single arthroplasty centre over the seven-year period of January 2015 to December 2021. Cases were defined as any adult patient undergoing revision hip or knee arthroplasty for aseptic loosening. Controls were randomly selected patients undergoing primary total hip or knee arthroplasty during the same period at a 1:4 ratio. Risk factors were compared between the two groups.

RESULTS

A total of 440 patients were included in our study - 88 in the aseptic loosening group and 352 patients in the control group. The odds of having diabetes mellitus in the aseptic loosening group was 2.78 (95%CI 1.31-5.92, P = 0.01). Other risk factors were not significantly different between the two groups.

CONCLUSIONS

The incidence of diabetes mellitus is significantly greater in patients undergoing revision arthroplasty for aseptic loosening. Further research is required to explore whether this association is indeed causative.

Targeted therapy for peri-prosthetic osteolysis using macrophage membrane-encapsulated human urine-derived stem cell extracellular vesicles

Aseptic loosening of the prosthesis is a severe complication after joint replacement. It is of great practical significance and social value to discover the prevention and treatment strategies for this condition. Exosomes from urine-derived stem cells (Exos) have great potential in promoting bone repair, reconstruction, and regulating bone metabolism. However, they are easily eliminated by macrophages and incapable of targeting the osteolysis zone. In this study, based on macrophage "homing" into periprosthetic osteolysis region and cell membrane encapsulating nanotechnology, exosomes from urine-derived stem cells were encapsulated with macrophage membrane (MM) to prevent periprosthetic osteolysis. We found that macrophage membrane encapsulated urine-derived stem cell-derived exosomes (MM-Exos) can be targeted delivery to the osteolysis zone and enhance the therapeutic effectiveness of Exos, which alleviated wear particles-induced calvarial osteolysis. Furthermore, MM-Exos could provide immunological camouflage and allow the Exos to avoid phagocytosis by macrophages and stimulate cellular uptake by bone marrow-derived stem cells (BMSCs). Therefore, we demonstrated the unique ability of the macrophage membrane as a targeted transport of exosomes from urine-derived stem cells for the prevention and treatment of periprosthetic osteolysis. These biomimetic nanoparticles provided a new therapeutic exosome delivery system for preventing wear particles-induced osteolysis. STATEMENT OF SIGNIFICANCE: Macrophage membrane encapsulated urine-derived stem cell-derived exosomes (MM-Exos) can be targeted delivery to the osteolysis zone and enhance the therapeutic effect of Exos on peri‑prosthetic osteolysis prevention. MM-Exos could allow the Exos to avoid phagocytosis by macrophages and promote the uptake of Exos by BMSCs.

Inhibitory effects of Formononetin on CoCrMo particle-induced osteoclast activation and bone loss through downregulating NF-κB and MAPK signaling

Wear particle-induced osteoclast over-activation is a major contributor to periprosthetic osteolysis and aseptic loosening, which can cause pathological bone loss and destruction. Hence, inhibiting excessive osteoclast-resorbing activity is an important strategy for preventing periprosthetic osteolysis. Formononetin (FMN) has been shown to have protective effects against osteoporosis, but no previous study has evaluated the effects of FMN on wear particle-induced osteolysis. In this study, we found that FMN alleviated CoCrMo alloy particles (CoPs)-induced bone loss in vivo and inhibited the formation and bone-resorptive function of osteoclasts in vitro. Moreover, we revealed that FMN exerted inhibitory effects on the expression of osteoclast-specific genes via the classical NF-κB and MAPK signaling pathways in vitro. Collectively, FMN is a potential therapeutic agent for the prevention and treatment of periprosthetic osteolysis and other osteolytic bone diseases.

Promising results of an non-invasive measurement of knee implant loosening using a loading device, CT-scans and 3D image analysis

BACKGROUND

After total knee arthroplasty up to 13% requires revision surgery to address loosening. No current diagnostic modalities have a sensitivity or specificity higher than 70-80% to detect loosening, leading to 20-30% of patients undergoing unnecessary, risky and expensive revision surgery. A reliable imaging modality is required to diagnose loosening. This study presents a new and non-invasive method and evaluates its reproducibility and reliability in a cadaveric study.

METHODS

Ten cadaveric specimens were implanted with a loosely fitted tibial components and CT scanned under load towards valgus and varus using a loading device. Advanced three-dimensional imaging software was used to quantify displacement. Subsequently, the implants were fixed to the bone and scanned to determine the differences between the fixed and the loose state. Reproducibility errors were quantified using a frozen specimen in which displacement was absent.

FINDINGS

Reproducibility errors, expressed as mean target registration error, screw-axis rotation and maximum total point motion were 0.073 mm (SD 0.033), 0.129 degrees (SD 0.039) and 0.116 mm (SD 0.031), respectively. In the loose condition, all displacements and rotation changes were larger than the reported reproducibility errors. Comparing the mean target registration error, screw axis rotation and maximum total point motion in the loose condition to the fixed condition resulted in mean differences of 0.463 mm (SD 0.279; p = 0.001), 1.769 degrees (SD 0.868; p < 0.001) and 1.339 mm (SD 0.712; p < 0.001), respectively.

INTERPRETATION

The results of this cadaveric study show that this non-invasive method is reproducible and reliable for detection of displacement differences between fixed and loose tibial components.

The influence of body weight index on initial stability of uncemented femoral knee protheses: A finite element study

Background and objective

Obesity is one of the risk factors for osteoarthritis. The end-stage treatment for osteoarthritis is total knee arthroplasty (TKA). However, it remains controversial whether a high body mass index (BMI) affects the initial stability of the femoral prosthesis after TKA. Finite element analysis (FEA) was used to investigate this question in this study.

Methods

Four femur models that assembled with TKA femoral components were reconstructed and divided into high BMI group and normal BMI group. The three-dimensional femurs were modeled and assigned inhomogeneous materials based on computed tomography (CT) images. Then each FEA model was applied with gait and deep bend loading conditions to evaluate the maximum principal strain on the distal femur and the relative micromotion between the femur and prosthesis.

Results

The mean strain of the high BMI group increased by 32.7% (936.9 με versus 706.1 με) and 50.9% (2064.5 με versus 1368.2 με) under gait and deep bend loading conditions, respectively, compared to the normal BMI group. Meanwhile, the mean micromotion of the high BMI group increased by 41.6% (2.77 μm versus 1.96 μm) and 58.5% (62.1 μm versus 39.2 μm), respectively. Under gait condition, the maximum micromotion for high BMI group was 33.8 μm and would compromise the initial stability. Under deep bend condition, the maximum strain and micromotion exceeded -7300 με and 28 μm for both groups.

Conclusion

High BMI caused higher strain on the bone and higher micromotion between the prosthesis and the femur. Gait activities could be risky for prosthesis stability in high BMI group while be safe in normal group. Deep bend activities were highly dangerous for both groups with high BMI and normal BMI and should be avoided.

Higher risk of 2-year cup revision of ceramic-on-ceramic versus ceramic-on-polyethylene bearing: analysis of 33,454 primary press-fit total hip arthroplasties registered in the Dutch Arthroplasty Register (LROI)

BACKGROUND AND PURPOSE

The influence of bearing on short-term revision in press-fit total hip arthroplasty (THA) remains under-reported. The aim of this study was to describe 2-year cup revision rates of ceramic-on-ceramic (CoC) and ceramic-on-polyethylene (CoPE).

PATIENTS AND METHODS

Primary press-fit THAs with one of the three most used cups available with both CoC or CoPE bearing recorded in the Dutch Arthroplasty Register (LROI) were included (2007-2019). Primary outcome was 2-year cup revision for all reasons. Secondary outcomes were: reasons for revision, incidence of different revision procedures and use of both bearings over time.

RESULTS

2-year Kaplan-Meier cup revision rate in 33,454 THAs (12,535 CoC; 20,919 CoPE) showed a higher rate in CoC (0.67% [95% CI, 0.54-0.81]) compared to CoPE (0.44% [95% CI, 0.34-0.54]) (p = 0.004). Correction for confounders (age, gender, cup type, head size) resulted in a hazard ratio (HR) of 0.64 [95%CI, 0.48-0.87] (p = 0.019). Reasons for cup revision differed only by more cup revision due to loosening in CoC (26.2% vs.1 3.2%) (p = 0.030). For aseptic loosening a revision rate of 0.153% [95% CI, 0.075-0.231] was seen in CoC and 0.058% [95%CI 0.019-0.097] in CoPE (p = 0.007). Correction for head size resulted in a HR of 0.475 [95% CI, 0.197-1.141] (p = 0.096). Incidence of different revision procedures did not differ between bearings. Over time the use of CoPE has increased and CoC decreased.

CONCLUSIONS

A higher 2-year cup revision rate in press-fit THA was observed in CoC compared to CoPE. Cup loosening was the only significantly different reason for revision and seen more often in CoC and mostly aseptic. Future randomised controlled trials need to confirm causality, since the early cup revision data provided has the potential to be useful when choosing the bearing in press-fit THA, when combined with other factors like bone quality and patient and implant characteristics.

Zingerone attenuates Ti particle-induced inflammatory osteolysis by suppressing the NF-κB signaling pathway in osteoclasts

Aseptic loosening caused by inflammatory osteolysis is one of the most frequent and serious long-term complications after total joint arthroplasty (TJA). Development of a new therapeutic drug is required due to the lack of effective therapy and serious adverse effects. This study aimed to explore the pharmacological properties of zingerone (ZO) in attenuating osteoclast-mediated periprosthetic osteolysis and how ZO modulates osteoclastogenesis. The nontoxic concentration of ZO was clarified by the CCK-8 method. Then, we explored the efficacy of ZO on suppressing osteoclast differentiation, F-actin ring formation, bone resorption, and NF-κB luciferase activity in vitro as well as osteoprotection in vivo. Polymerase chain reaction and western blotting were applied to detect the underlying mechanisms involved in osteoclastogenesis. ZO showed an obvious inhibitory effect on osteoclastogenesis and bone resorption in a dose-dependent manner by mainly suppressing the activation of NF-κB signaling pathways. Furthermore, ZO administration successfully attenuated titanium (Ti) particle-stimulated periprosthetic osteolysis and osteoporosis by regulating osteoclast formation. Our findings demonstrated the pharmacological properties of ZO in inhibiting osteoclast formation and function by downregulation of NF-κB signaling activation. As a result, these findings could be expected to provide a novel reagent for regulating inflammatory osteolysis caused by prosthetic loosening.

A randomized controlled trial comparing two-year postoperative femoral and tibial migration of a new and an established cementless rotating platform total knee arthroplasty

AIMS

The primary aim of this study was to compare the migration of the femoral and tibial components of the cementless rotating platform Attune and Low Contact Stress (LCS) total knee arthroplasty (TKA) designs, two years postoperatively, using radiostereometric analysis (RSA) in order to assess the risk of the development of aseptic loosening. A secondary aim was to compare clinical and patient-reported outcome measures (PROMs) between the designs.

METHODS

A total of 61 TKAs were analyzed in this randomized clinical RSA trial. RSA examinations were performed one day and three, six, 12, and 24 months postoperatively. The maximal total point motion (MPTM), translations, and rotations of the components were analyzed. PROMs and clinical data were collected preoperatively and at six weeks and three, six, 12, and 24 months postoperatively. Linear mixed effect modelling was used for statistical analyses.

RESULTS

The mean MTPM two years postoperatively (95% confidence interval (CI)) of the Attune femoral component (0.92 mm (0.75 to 1.11)) differed significantly from that of the LCS TKA (1.72 mm (1.47 to 2.00), p < 0.001). The Attune femoral component subsided, tilted (anteroposteriorly), and rotated (internal-external) significantly less. The mean tibial MTPM two years postoperatively did not differ significantly, being 1.11 mm (0.94 to 1.30) and 1.17 mm (0.99 to 1.36, p = 0.447) for the Attune and LCS components, respectively. The rate of migration in the second postoperative year was negligible for the femoral and tibial components of both designs. The mean pain-at-rest (numerical rating scale (NRS)-rest) in the Attune group was significantly less compared with that in the LCS group during the entire follow-up period. At three months postoperatively, the Knee injury and Osteoarthritis Outcome Physical Function Shortform score, the Oxford Knee Score, and the NRS-activity scores were significantly better in the Attune group.

CONCLUSION

The mean MTPM of the femoral components of the cementless rotating platform Attune was significantly less compared with that of the LCS design. This was reflected mainly in significantly less subsidence, posterior tilting, and internal rotation. The mean tibial MTPMs were not significantly different. During the second postoperative year, the components of both designs stabilized and low risks for the development of aseptic loosening are expected.Cite this article: Bone Joint J 2023;105-B(2):148-157.

HUCMSC-derived Exosomes Suppress the Titanium Particles-induced Osteolysis in Mice through Inhibiting CCL2 and CCL3

OBJECTIVE

Wear particles induce inflammation and the further osteolysis around the prosthesis, has been proven to be the main cause of aseptic hip joint loosening. In this research, we aimed to clarify whether human umbilical cord mesenchymal stem cells (HUCMSCs) could inhibit the titanium particles-induced osteolysis and shed light upon its mechanism.

METHODS

The expression of chemokine (C-C motif) ligand 2 (CCL2), chemokine (C-C motif) ligand 3 (CCL3) and chemokine (C-C motif) ligand 5 (CCL5) were examinjed in clinical specimens of aseptic hip prosthesis loosening patients. Local injection of lentivirus that knocked down CCL2 or CCL3 in a cranial osteolysis mice model were used to exam the effect of CCL2 and CCL3 on titanium particles-induced osteolysis in vivo. Transwell assay was used to examine the effect of CCL2 and CCL3 on titanium particles-induced activation of macrophage in vitro. Furthermore, the therapeutic effect of HUCMSCs, and exosomes from HUCMSCs were also examed in vivo and vitro. Immunohistochemical and real-time PCR were used to examine the expression of relative pathways. Analysis of variance (ANOVA) and Student-Newman-Keuls post hoc t test were used to analyze the results and determine the statistical significance of the differences.

RESULTS

Results showed that titanium particles caused the osteolysis at the mice cranial in vivo and a large number of macrophages that migrated, while local injection of HUCMSCs and exosomes did inhibit the cranial osteolysis and migration. An exosome inhibitor GW4869 significantly increased the osteolysis area in the mice cranium osteolysis model, and increased the number of migrated macrophages. Immunohistochemical results suggested that the expression of CCL2, CCL3 and CD68 in the cranial in Titanium particles mice increased significantly, but was significantly reduced by HUCMSCs or exosomes. HUCMSC and exosomes down-regulate the expression of CCL3 in vitro and in vivo.

CONCLUSION

HUCMSCs and HUCMSC-derived exosomes could suppress the titanium particles-induced osteolysis in mice through inhibiting chemokine (C-C motif) ligand 2, chemokine (C-C motif) ligand 3.

Additively manufactured controlled porous orthopedic joint replacement designs to reduce bone stress shielding: a systematic review

BACKGROUND

Total joint replacements are an established treatment for patients suffering from reduced mobility and pain due to severe joint damage. Aseptic loosening due to stress shielding is currently one of the main reasons for revision surgery. As this phenomenon is related to a mismatch in mechanical properties between implant and bone, stiffness reduction of implants has been of major interest in new implant designs. Facilitated by modern additive manufacturing technologies, the introduction of porosity into implant materials has been shown to enable significant stiffness reduction; however, whether these devices mitigate stress-shielding associated complications or device failure remains poorly understood.

METHODS

In this systematic review, a broad literature search was conducted in six databases (Scopus, Web of Science, Medline, Embase, Compendex, and Inspec) aiming to identify current design approaches to target stress shielding through controlled porous structures. The search keywords included 'lattice,' 'implant,' 'additive manufacturing,' and 'stress shielding.'

RESULTS

After the screening of 2530 articles, a total of 46 studies were included in this review. Studies focusing on hip, knee, and shoulder replacements were found. Three porous design strategies were identified, specifically uniform, graded, and optimized designs. The latter included personalized design approaches targeting stress shielding based on patient-specific data. All studies reported a reduction of stress shielding achieved by the presented design.

CONCLUSION

Not all studies used quantitative measures to describe the improvements, and the main stress shielding measures chosen varied between studies. However, due to the nature of the optimization approaches, optimized designs were found to be the most promising. Besides the stiffness reduction, other factors such as mechanical strength can be considered in the design on a patient-specific level. While it was found that controlled porous designs are overall promising to reduce stress shielding, further research and clinical evidence are needed to determine the most superior design approach for total joint replacement implants.

Anatomical risk factors for aseptic loosening of full hinge knee prosthesis in primary and revision TKAs

INTRODUCTION

Risk factors (RF) associated with aseptic loosening (AL) in total knee arthroplasty (TKA) are poorly understood. Therefore, the aim of this study was to investigate the anatomical shape variations in relation to the inner-diameter of the femur and the tibia as prognostic RF for AL of full hinge prosthesis (FHP) in primary and revision TKA.

MATERIALS AND METHODS

We retrospectively examined all patients, who underwent revision surgery (2003-2018) due to AL of the FHP in primary (n = 38) and revision TKA (n = 46). Diagnosis-appropriate controls without AL at minimum follow-up of 24 months were randomly collected for each group. Besides other risk factors, we also measured the inner diameter of the femur according to the Citak classification and of the tibia on anteroposterior radiographies.

RESULTS

RF for AL are younger age in primary and revision as well as > 1 previous surgeries in revision TKA. The femoral index was shown to be a RF for AL in revision TKA (p = 0.001), but not in primary TKA. The novel tibial index was associated with AL in primary with AUC 0.776 (95% CI 0.67, 0.88), 65.8% sensitivity, 86.6% specificity and in revision TKA with AUC 0.817 (95% CI 0.73, 0.91), 82.6% sensitivity and 71.7% specificity.

CONCLUSION

This is the first study to calculate the tibial measurements and the tibial index according to Citak et al. and to identify them as prognostic RF for AL of the full hinge knee prosthesis in TKA and confirm the femoral index as a RF for AL also in revision full hinge knee prosthesis. Therefore, the preoperative radiological evaluation should include the analysis of the anatomical shape variants in order to select the appropriate prosthesis design with a possibly enhanced prognosis.

A low dislocation rate after revision total hip arthroplasty performed through the anterior approach

BACKGROUND

Dislocation is a major complication in revision total hip arthroplasties. This study aimed to evaluate the dislocation rate, complications, and functional scores of revision total hip arthroplasty performed through the direct anterior approach.

METHODS

Between January 2014 and March 2020, 84 patients undergoing revision total hip arthroplasty were retrospectively reviewed. All operations were performed through the direct anterior approach. At the final follow-up, incidences of dislocation, reoperation, acute deep infections, periprosthetic fractures and psoas impingement were assessed. The median postoperative Oxford Hip Score was also calculated.

RESULTS

At revision surgery, the mean age was 66 ± 12 years (range, 28-91). During an average follow-up of 4.2 ± 1.2 years, reoperation rate for major complications in the non-infected revisions was 15% (n = 11), including five acute deep infections (7%), four periprosthetic fractures (5%), one dislocation and one psoas impingement (1%). The median postoperative Oxford Hip Score was 39 (interquartile range = 14).

CONCLUSION

In our series, revision total hip arthroplasty through direct anterior approach was associated with a very low dislocation rate, acceptable complication rates and good functional results. Our results suggest that this procedure is safe and reliable.

TRIAL REGISTRATION

Ethical approval for this study was obtained, before enrollment of the first participant, by CUB Erasme's research ethics committee (P2020/323) and C.H.U Ambroise Paré's research ethics committee.

Mid-term effect of total knee arthroplasty with and without tourniquet use on prosthesis survival, complications and functional outcome: A prospective cohort study of 511 total knee arthroplasties

BACKGROUND

A tourniquet is often used to create a bloodless surgical field during total knee arthroplasty (TKA). It is still debated whether tourniquet use improves durability of cemented implant fixation and thereby prosthesis survival. Some studies showed tourniquet application has a negative impact on post-operative wound healing, pain and function, whilst other publications contradict this. However, no previous studies evaluated the effect of tourniquet use on prosthesis survival and mid-term functional outcome specifically.

METHODS

In this longitudinal observational cohort study 115 patients (116 knees) undergoing TKA without tourniquet use were compared with 374 patients (395 knees) with a tourniquet. Prosthesis survival, revision risks and complications were analysed through chart review after ameanfollow-up period of5.3 years.Additionally, patient reported outcome measures regarding knee functionality and health status (PROMs; KOOS, OKS, EQ-5D, SF-12) werecollected prospectively.

RESULTS

Both groups had an equal overall re-operation rate of 4.3% and showed similar revision rates for aseptic loosening as well as for other causes. In the tourniquet group a higher complication rate (14.7% vs 10.3%) was observed. The majority was urinary retention requiring bladder catheterization. Both groups showed comparable, improved post-operative functional results compared to the pre-operative state for all PROMs atall timepoints.

CONCLUSIONS

In this study TKA without tourniquet use yielded similar mid-term results as TKA with tourniquet use with regard to prosthesis survival, reoperations, complications, knee functionality and health status.

Total Knee Arthroplasty with Non-Stemmed Tibial Components among Obese Patients: Clinical and Radiologic Evaluation and Review of Literature

Objective

This study aimed to evaluate the radiologic and clinical outcomes of TKA with non-stemmed tibial components in relation to their body mass index (BMI).

Methods

In this retrospective cohort study, the outcome of TKA with non-stemmed tibial components based on their BMI was evaluated (BMI<30 vs. BMI≥30). The patients' function was assessed using the International Knee Documentation Committee (IKDC) and Lysholm knee questionnaires. Radiologic evaluation for probable signs of loosening was performed using two quantitative scoring systems by Ewald and Bach et al. Moreover, we reviewed the current literature on the application of non-stemmed tibial components in obese patients.

Results

Twenty-one patients (two men and 19 women) with BMI≥30 and a mean age of 65.1±9.5 years, and 22 patients (three men and 19 women) with BMI<30 and a mean age of 63.6±8.5 years were studied. The mean follow-up periods with BMI≥30 (47.0±19.8 months) and BMI<30 (49.2±18.7 months) were comparable (p=0.618). No patients in either group experienced clinical loosening. Besides, none of the patients had any kind of revision surgery. The patients in both BMI groups had comparable IKDC scores (both the total score and its sub-scores; p>0.05). Furthermore, the total Lysholm knee scores were similar in both groups (p=0.122). Using both scoring systems, the peri-prosthetic bone radiolucency near the tibial components was similar in both groups (p>0.999).

Conclusion

The present study found no significant difference in the radiologic or clinical outcome of non-stemmed TKA in patients with BMIs under and over 30.