Patients Undergoing Revision Total Hip Research Articles

Operative time greater than 120minutes is associated with increased pulmonary and thromboembolic complications following revision total hip arthroplasty.

The aim of this study was to determine the impact of operative time on the development of early postoperative complications in patients undergoing revision total hip arthroplasty (THA). In this retrospective cohort study, data were collected through the American College of Surgeons National Quality Improvement Program Database. All patients who underwent revision THA between 2007 and 2016 were identified and stratified into groups based on operative time|: 0-60min, 61-120min, 121-180min, and > 180min. The incidence of early postoperative adverse events with 30days, including cardiac, pulmonary, renal, septic, thromboembolic, urinary tract, and wound complications, death, length of stay > 7days, and unplanned return to the operating room were collected. The complications rates following revision THA were evaluated with univariate and multivariate analyses with significance set at p < 0.05. A total of 6271 revision THA patients were included for analysis. Patients who had > 120min of operative time had a significantly increased risk of the development of pulmonary (OR: 1.339; 95% CI: 1.08-1.661; p = 0.008) and thromboembolic complications (OR: 1.34; 95% CI: 1.053-1.707; p = 0.017) and also had an extended length of stay greater than 7days (OR: 1.413; 95% CI: 1.295-1.541; p < 0.001). Increased operative time (> 120min) during revision THA is associated with increased risk of pulmonary and thromboembolic complications, and prolonged hospitalizations (greater than seven days).

Low-Dose Aspirin Is Safe and Effective for Venous Thromboembolism Prevention in Patients Undergoing Revision Total Hip Arthroplasty: A Retrospective Cohort Study

BackgroundCurrently, there is no established universal standard of care for prophylaxis against venous thromboembolism (VTE) in orthopedic patients undergoing revision total hip arthroplasty (rTHA). The aim of this study is to determine whether a protocol of 81-mg aspirin (ASA) bis in die (BID) is safe and/or effective in preventing VTE in patients undergoing rTHAs vs 325-mg ASA BID. MethodsIn 2017, a large academic medical center adopted a new protocol for VTE prophylaxis in arthroplasty patients at standard risk. Initially, patients received 325-mg ASA BID but switched to 81-mg ASA BID. A retrospective review (2011-2019) was performed to identify 1361 consecutive rTHA patients and their associated 90-day postoperative complications such as VTE, including pulmonary embolism (PE) and/or deep vein thrombosis (DVT), as the primary outcome; and gastrointestinal and wound bleeding, acute periprosthetic joint infection, and mortality as the secondary outcome. ResultsFrom 2011 to 2017, 973 rTHAs were performed and 13 total VTE cases were diagnosed (1.34%). From 2017 to 2019, 388 rTHAs were performed with 3 total VTE cases identified (0.77%). Chi-squared analyses and logistic regression models showed no differences in rates or odds in postoperative PE (P = .09), DVT (P = .79), PE and DVT (P = .85), and total VTE (P = .38) using either dose. There were also no differences between bleeding complications (P = .14), infection rate (P = .46), and mortality (P = .53). ConclusionUsing a protocol of 81-mg of ASA BID is noninferior to 325-mg ASA BID and may be safe and effective in maintaining low rates of VTE in patients undergoing rTHA.

Cementation of a monoblock dual mobility bearing in a newly implanted porous revision acetabular component in patients undergoing revision total hip arthroplasty.

BackgroundThe most common indications for revision total hip arthroplasty are instability/dislocation and mechanical loosening. Efforts to address this have included the use of dual mobility (DM) articulations. The aim of this study is to report on the use of cemented DM cups in complex acetabular revision total hip arthroplasty cases with a high risk of recurrent instability.MethodsA multicenter, retrospective study was conducted. Patients who received a novel acetabular construct consisting of a monoblock DM cup cemented into a fully porous metal shell were included. Outcome data included 90-day complications and readmissions, revision for any reason, and Harris Hip Scores.ResultsThirty-eight hips in 38 patients were included for this study. At a median follow-up of 215.5 days (range 6-783), the Harris Hip Score improved from a mean of 50 ± 12.2 to 78 ± 11.2 (P < .001). One (2.6%) patient experienced a dislocation on postoperative day 1, and was closed reduced with no further complications. There was 1 (2.6%) reoperation for periprosthetic joint infection treated with a 2-stage exchange.ConclusionsIn this complex series of patients, cementation of a monoblock DM cup into a newly implanted fully porous revision shell reliably provided solid fixation with a low risk of dislocation at short-term follow-up. Although longer term follow-up is needed, utilization of this novel construct should be considered in patients at high risk for instability.

Can leucocyte esterase replace frozen sections in the intraoperative diagnosis of prosthetic hip infection?

Leucocyte esterase (LE) has been shown to be an accurate marker of prosthetic joint infection (PJI), and has been proposed as an alternative to frozen section (FS) histology for intraoperative diagnosis. In this study, the intraoperative assessment of LE was compared with FS histology for the diagnosis of prosthetic hip infection. A total of 119 patients undergoing revision total hip arthroplasty (THA) between June 2015 and December 2017 were included in the study. There were 56 men and 63 women with a mean age of 66.2 years (27 to 88). Synovial fluid was collected before arthrotomy for the assessment of LE using enzymatic colourimetric strips. Between five and six samples were stained with haematoxylin and eosin for FS histology, and considered suggestive of infection when at least five polymorphonuclear leucocytes were found in five high-power fields. The sensitivity and specificity of the LE assay were 100% and 93.8%, respectively; the positive (PPV) and the negative (NPV) predictive values were 79.3% and 100%, respectively. The mean time between the collection of the sample and the result being known was 20.1 minutes (sd 4.4). The sensitivity and specificity of FS histology were 78.3% and 96.9%, respectively; the PPV and the NPV were 85.7% and 94.9%, respectively. The mean time between the collection of the sample and the result being known was 27.2 minutes (sd 6.9). The sensitivity of LE assay was higher, with similar specificity and diagnostic accuracy, compared with FS histology. The faster turnaround time, its ease of use, and low costs make LE assay a valuable alternative to FS histology. We now use it routinely for the intraoperative diagnosis of PJI. Cite this article: Bone Joint J 2019;101-B:372-377.

Frailty Predicts Medical Complications, Length of Stay, Readmission, and Mortality in Revision Hip and Knee Arthroplasty

BackgroundThe purpose of this study is to evaluate the 5-factor modified frailty index (mFI-5) as a predictor of postoperative complications, readmission, and mortality in patients undergoing revision hip and knee arthroplasty. MethodsA retrospective analysis of the American College of Surgeon’s National Surgical Quality Improvement Program’s database for patients undergoing revision total hip arthroplasty (rTHA) and revision total knee arthroplasty (rTKA) between the years 2005 and 2016 was conducted. The 5-factor score, which includes presence of comorbid diabetes, hypertension, congestive heart failure, chronic obstructive pulmonary disease, and functional status, was calculated for each patient. Multivariate logistic regression models were used to assess the relationship between the mFI-5 and postoperative complications while controlling for demographic variables. ResultsIn total, 13,948 patients undergoing rTHA and 16,304 patients undergoing rTKA were identified. The mFI-5 was a strong predictor of serious medical complications (cardiac arrest, myocardial infarction, septic shock, pulmonary embolism, postoperative dialysis, reintubation, and prolonged ventilator requirement), discharge to a facility, total length of stay, readmission, and mortality (P ≤ .007). ConclusionThe mFI-5 predicts serious medical complications, increased length of stay, discharge to a facility, hospital readmission, and mortality in patients undergoing rTHA and rTKA. All the variables within the mFI-5 are easily obtained through the patient history, allowing for a practical clinical tool that hospitals and physicians can use to identify at-risk patients, educate and engage patients and their families in a shared decision-making conversation, and guide perioperative care in order to optimize patient outcomes. Level of EvidenceIII.

Proximal femoral replacement in non-oncologic patients undergoing revision total hip arthroplasty.

Proximal femoral replacements (PFRs) have been recently utilized in complex revision arthroplasties where proximal femoral bone is compromised. The purpose of this study is to evaluate the clinical outcomes, complications, and survivorship of PFRs as a salvage treatment for severe bone loss after non-oncologic revision total hip arthroplasty. This is a retrospective review of all patients who underwent femoral revision surgery using a single design PFR between 2004 and 2013 at our institution. Forty patients (41 hips) were included with a mean age of 64years (29-90). According to Paprosky classification, 15 femurs had type IIIB defect, and 26 had type IV defect. Patients were followed for a mean of five years (2-10). The average length of reconstruction was 150mm (81-261). A Kaplan-Meier analysis was used to determine the survival of the PFR. A total of nine patients (9 PFRs, 22%) were re-operated upon. Three re-operations were for infection, two for dislocation, two for aseptic loosening, and two for periprosthetic fracture. The survivorship at fiveyears was 95.1% for revision of the femoral stem for aseptic loosening. We did not find length of the segmental reconstruction or the indication for revision, to be a risk factor for implant failure or re-revision. Proximal femoral replacements have shown an acceptable survivorship in non-oncologic revision hip arthroplasties for severe proximal femoral bone loss. The frequent use of constrained liners may decrease the risk of dislocation due to the loss of the abductor mechanism encountered in these complex reconstructions.

Results of trabecular metal augments in Paprosky IIIA and IIIB defects

The advent of trabecular metal (TM) augments has revolutionized the management of severe bone defects during acetabular reconstruction. The purpose of this study was to evaluate patients undergoing revision total hip arthroplasty (THA) with the use of TM augments for reconstruction of Paprosky IIIA and IIIB defects. A retrospective study was conducted at four centres between August 2008 and January 2015. Patients treated with TM augments and TM shell for a Paprosky grade IIIA or IIIB defect, in the absence of pelvic discontinuity, and who underwent revision hip arthroplasty with the use of TM augments were included in the study. A total of 41 patients with minimum follow-up of two years were included and evaluated using intention-to-treat analysis. There were 36 (87.8%) patients with a Paprosky IIIA defect and five (12.2%) patients with a Paprosky IIIB defect. The mean age was 56.7 years (28 to 94). There were 21 (51.2%) women and 20 (48.8%) men. The mean follow-up was 39.4 months (12 to 96). One (2%) patient died after eight years. No failures were noted in the series. The mean survivorship was 100% at the time of latest follow-up. The results of this multicentre study showed encouraging short- and mid-term results for the use of TM augments in the management of Paprosky grade IIIA and IIIB defects. Cite this article: Bone Joint J 2018;100-B:903-8.

Femoral Bone Restoration Patterns in Revision Total Hip Arthroplasty Using Distally Fixed Modular Tapered Titanium Stems and an Extended Trochanteric Osteotomy Approach

BackgroundMechanical failure of modular revision stems is a serious complication in revision total hip arthroplasty. The lack of adequate osseous support to the proximal component, especially in cases of an extended trochanteric osteotomy approach, is considered a risk factor for stem failure. In this study, we analyze proximal bone regeneration patterns in patients undergoing revision total hip arthroplasty for aseptic stem loosening through an extended trochanteric osteotomy approach using an uncemented dual modular stem. MethodsFifty-four patients treated for aseptic stem loosening were radiologically reviewed. The femur was divided according to the Gruen zones. Preoperative bone loss, formation of new cancellous bone, and presence of direct osseous contact to the stem were noted right away for each Gruen zone. The presence of osseous support at the modular junction and the proximal component were examined. ResultsAll patients showed restoration of proximal bone mass at final follow up. New bone formation was first seen in more distally located Gruen zones. Cases with longer proximal components had a trend toward earlier osseous support at the modular junction. Overall, 75% of patients showed osseous support at the modular junction 2 years after surgery. ConclusionRestoration of proximal bone occurs in a distal to proximal direction. Shorter proximal components require more time until osseous support to the modular junction is achieved, which may result in a higher risk of mechanical failure. Based on this study, bony support at the modular junction should not be expected in 25% of cases 2 years after surgery.

Obesity is associated with higher complication rates in revision total hip arthroplasty

We examined differences in complication rates between obese and non-obese patients undergoing revision total hip arthroplasty. Sixty-five patients with a BMI ≥30 kg/m2 and 54 patients with a BMI of <30 kg/m2 were identified. Obese patients were 2.5 times more likely to suffer a complication than non-obese (38.4% cf 14.8%, p = 0.02). Obese patients were more likely to experience dislocation, leg length discrepancy, fracture, implant loosening, infection and pulmonary embolus. The obese group had a significantly higher revision rate (12.3% cf 1.8%, p = 0.039). Obese patients should be counselled pre-operatively on their elevated risk.

K-Wire Technique for the Removal of Uncemented Femoral Stem in Revision THA

In this work, K wires were used for 5 patients undergoing revision total hip arthroplasty to remove well-fixed, uncemented femoral stem without osteotomy. The technique was successful and considered to be safer and more economic than osteotomy with shorter operative time and easier surgical set up.

Increased rate of bacterial colonization on PE-components in total joint arthroplasty: An evaluation through sonication

It is currently unclear if an isolated exchange of the mobile components, in cases of periprosthetic joint infection (PJI), leads to a complete eradication of all bacteria or if residual bacteria remain attached to the retained components? The purpose of this study was to investigate if bacteria only adhere to certain components or materials, or if they are ubiquitously distributed throughout the joint. Twenty hundred and eighty four patients undergoing revision total hip or total knee arthroplasty surgery were included in this retrospective cohort study. Synovial fluid cultures, periprosthetic tissue cultures, histological samples and sonicate fluid cultures (SFC) from the individual endoprosthetic components were acquired. The isolated bacterial species were recorded according to their endoprosthetic component of origin. In 72% of all cases with multiple SFC, the cultures were concordant with all samples being either homogenously negative or showing positive bacterial growth. The polyethylene (PE) components showed a significantly higher rate of bacterial isolation than the non-mobile components. All components and materials showed bacterial colonization, however between all other components or materials were not statistically significant. PE-components show a higher rate of bacterial isolation than other components. If an isolated bearing exchange is performed this should be supplemented by adequate antimicrobial therapy.

The Rule of Histology in the Diagnosis of Periprosthetic Infection: Specific Granulocyte Counting Methods and New Immunohistologic Staining Techniques may Increase the Diagnostic Value.

Objective:The current study investigates the diagnostic accuracy of the criteria described for frozen sections and whether modern leukocyte specific staining techniques including leukocyte peroxidase and Naphtol-AS-D-chloroacetate-esterase will improve the accuracy of the intra-operative histology.Method:77 patients undergoing revision total hip and knee arthroplasty were included in this retrospective study. Patients were grouped into septic and aseptic based on intraoperative cultures. Tissue samples were analyzed utilizing the Mirra, Feldman, Lonner, Banit and Athanasou criteria.Results:An experienced pathologist had a high specificity (96%), but rather low sensitivity (57%) diagnosing infection. By using the Banit-, Mirra-, or Athanasou-criteria the sensitivity is increased to 0.90. The Feldman- and Lonner-criteria have a lower sensitivity (0.48 and 0.38), however, an increased specificity of 0.96 and 0.98, respectively. The Banit cut off has the highest accuracy (86%). MPOX and NACE staining increased the sensitivity and accuracy up to 100% and 92% respectively.Conclusion:Banit’s cut off is the most accurate histologic criteria to diagnose infection. Modern leukocyte specific staining techniques slightly improve the accuracy. The synovial fluid white blood cell count appears to be the most accurate intraoperative test.

The Extended Direct Anterior Approach for Column Augmentation in the Deficient Pelvis: A Novel Surgical Technique, and Case Series Report

BackgroundAnterior column deficiency of the pelvis may pose a serious threat to the stability of the acetabular component after total hip arthroplasty and, thus, jeopardize the overall success of the procedure. MethodsAfter Institutional Review Board approval, a retrospective review was undertaken to identify all patients undergoing revision total hip arthroplasty with anterior column augmentation through an extended direct anterior approach. Demographics and surgical details were collected, and subjects were followed for a 2-year minimum period to measure patient outcomes and to evaluate for the stability of construct fixation. A novel surgical procedure description was provided and supplemented with an illustrative case example. ResultsAt 2 years post augmentation, patients had favorable functional outcomes with radiologic evidence of stable fixation. ConclusionProximal extension of the direct anterior approach to the hip can facilitate anterior column access and augmentation to improve stability of the hip reconstruction. This treatment may be an alternative to spanning constructs such as cup-cage constructs and custom implants, affording the potential for long-term biologic fixation. Further investigation into this technique is warranted.

Review of the outcomes of complex acetabular reconstructions using a stemmed acetabular pedestal component.

Until now, there has been no consensus as to whether stemmed acetabular components are appropriate for use in patients undergoing revision total hip arthroplasty (THA) who have major acetabular defects or pelvic discontinuity. We wished to address this deficiency in the literature. We carried out a retrospective study of 35 patients (six men and 29 women) with a mean age of 68 years (37 to 87), with major acetabular defects who underwent revision THA between 2000 and 2012. At a mean follow-up of 63 months (24 to 141), a total of 15 patients (43%) had required at least one further operation. Six implants (17%) loosened aseptically, four (11%) were further revised for infection and two (6%) for technical failure. By taking revision for any reason as the endpoint, the rate of survival of the implant was 61% after five years; by taking revision for aseptic loosening as the end point, it was 78%. The cumulative five-year survival for aseptic loosening was 94% in patients without pelvic discontinuity, and 56% in those with pelvic discontinuity. These results indicate a significantly worse survival in patients with pelvic discontinuity (p=0.020) and we advise caution in the use of the pedestal component in patients with major acetabular defects and pelvic discontinuity who require revision THA. As a result of these findings we have stopped using this implant and prefer to use particulate bone grafts protected with an anti-protrusion cage and posterior column plate fixation, if necessary. Based on these poor results, we advise caution if using the pedestal component in patients with major acetabular defects with the presence of a pelvic discontinuity. Cite this article: Bone Joint J 2016;98-B:772-9.

Complications in diabetic patients undergoing revision total joint arthroplasty

Background: The risks of complications in individuals with diabetes undergoing primary total joint arthroplasty are well discussed in the literature; however, little is written about their risks with revision procedures. This study evaluates complications surrounding revision arthroplasty in diabetics compared with controls. Methods: Six hundred and thirty-five patients underwent revision total hip and knee surgery since 2004. Sixty-five diabetics who underwent revision arthroplasty were compared to 65 matched controls. Demographics, comorbidities, and hemoglobin A1c (HgbA1c) levels were analyzed in comparison to complications encountered. Results: Of the 635 revision arthroplasty patients sampled, 10.2% (65/635) of patients had both diabetes and HgbA1c levels drawn. Thirty (46%) diabetic patients experienced 58 complications and required 25 additional procedures. Twenty-three (35%) controls experienced 35 complications and had 22 additional procedures. HgbA1c levels were a median (quartiles) of 5.90 (5.60–6.40) among diabetics without a complication, compared to 6.55 (6.10–7.20) among diabetics with at least one complication (P=0.0006). The number of complications was also strongly correlated with patient’s HbA1c (Spearman’s rho=0.417; P=0.0009). Diabetic patients had a higher complication rate and number of complications than controls. Diabetic patients were at higher risk of developing infections (18.4% vs. 4.6%; P=0.025), periprosthetic fractures (9.2% vs. 0%; P=0.028), and more severe rare complications (P=0.0029). Conclusions: The study suggests that diabetics with better glycemic control tend to have fewer complications. Diabetics undergoing revision arthroplasty appear to be at a higher risk of developing infections, periprosthetic fractures, and rare events than nondiabetics.

High Failure Rate of Modular Exchange With a Specific Design of a Constrained Liner in High-Risk Patients Undergoing Revision Total Hip Arthroplasty

BackgroundAddressing recurrent instability in patients with poor bone stock and inadequate abductor tensioning remains a challenge in revision total hip arthroplasty. One treatment method is implantation of a constrained liner. The purpose of this study was to determine clinical outcomes, redislocation rate, and revisions of a focally constrained liner in a high-risk patient cohort. MethodsFifty-eight hips between 2008 and 2011 underwent implantation of a focally constrained liner. Nineteen were placed concurrent with acetabular component revision and 39 were placed into a well-fixed acetabular shell. Mean age was 69 years and mean number of previous ipsilateral hip surgeries was 4.2. At mean follow-up of 3.5 years, we analyzed clinical outcomes, redislocation, and revisions. ResultsMean Harris Hip Scores was 74. Fourteen hips (24%) were revised and 3 hips (5%) required reoperation at final follow-up. Eleven hips (19%) redislocated at a mean time to dislocation of 12.2 months; 31% (11 of 36 patients) that underwent modular exchange specifically for instability redislocated. Risk factors for redislocation included number of previous surgeries (P = .013), implantation of a 28 mm femoral head (hazards ratio 12.8), revision indication of instability (P = .04), and modular exchange with constrained liner implantation without acetabular shell revision (P = .01). ConclusionImplantation of a focally constrained liner in revision total hip arthroplasty for recurrent instability has a high failure rate, especially with a modular exchange. Although concurrent acetabular revision had a lower redislocation rate, the decision to revise a well-fixed cup should be weighed with potential complications associated with cup revision.

Evidence that osteocyte perilacunar remodelling contributes to polyethylene wear particle induced osteolysis

Periprosthetic osteolysis (PO) leading to aseptic loosening, is the most common cause of failure of total hip replacement (THR) in the mid- to long-term. Polyethylene (PE) particulates from the wear of prosthesis liners are bioactive and are implicated in the initiation and or progression of osteolysis. Evidence exists that cells of the osteoblast/osteocyte lineage are affected by PE particles and contribute to the catabolic response by promoting osteoclastic bone resorption. In this study, we hypothesised that osteocytes contribute directly to PO by removing bone from their perilacunar matrix. Osteocyte responses to ultra-high molecular weight PE (UHMWPE) particles were examined in vitro in human primary osteocyte-like cultures, in vivo in the mouse calvarial osteolysis model, and in the acetabulum of patients undergoing revision total hip replacement (THR) surgery for PO. Osteocytes exposed to UHMWPE particles showed upregulated expression of catabolic markers, MMP-13, carbonic anhydrase 2 (CA2), cathepsin K (CTSK) and tartrate resistant acid phosphatase (TRAP), with no effect on cell viability, as assessed by Caspase 3 activity. Consistent with this catabolic activity causing perilacunar bone loss, histological analysis of calvarial sections from mice exposed to UHMWPE revealed a significant (p<0.001) increase in osteocyte lacunar area (Lac.Ar) compared to sham-operated animals. Furthermore, acetabular biopsies from patients with PO also showed significantly (p<0.001) increased osteocyte lacunar size in trabecular bone adjacent to PE particles, compared with osteocyte lacunar size in bone from primary THR patients. Together, these findings suggest a previously unrecognised action of UHMWPE wear particles on osteocytes, which directly results in a loss of osteocyte perilacunar bone. This action may exacerbate the indirect pro-osteoclastic action of UHMWPE-affected osteocytes, previously shown to contribute to aseptic loosening of orthopaedic implants. Statement of SignificanceThis study addresses the clinical problem of periprosthetic osteolysis, bone loss in response to polyethylene wear particles derived from materials used in orthopaedic implants. Periprosthetic osteolysis has been thought to be due largely to wear particles stimulating the activity of bone resorbing osteoclasts. However, in this study we demonstrate for the first time that polyethylene particles stimulate another type of bone loss, mediated by the direct activity of bone mineral embedded osteocytes, termed osteocytic osteolysis or osteocyte perilacunar remodelling. This study provides new mechanistic insight into wear-particle mediated bone loss and represents a new paradigm for the way in which bone cells, namely osteocytes, the key controlling cell type in bone, react to biomaterials.

Use of a Thrombin Fibrin Sealant in Reducing Blood Loss in Revision Hip Arthroplasty.

We present a retrospective evaluation assessing the use of a novel fibrin sealant, Quixil® (OMRIX Biopharmaceuticals S.A.) in reducing blood transfusions following revision total hip replacement surgery. Forty four patients underwent revision total hip replacement surgery using Quixil®, while 45 patients underwent revision total hip replacement surgery without the use of Quixil®. The duration of surgery and patient demographics were similar in both groups. Average blood loss was 1,010ml in the Quixil® group versus 1,021ml in the non-Quixil group. The use of cell saver and intra-operative blood transfusion were similar in both groups. The mean pre-operative Haemoglobin was 13.0 g/dl in the Quixil® group versus 12.4 g/dl in the non-Quixil group. The mean post-operative haemoglobin was 10.2 g/dl and 9.1 g/dl in the Quixil® and non-Quixil groups respectively. There was no difference in the blood transfused post-operatively between the two groups. Total units of blood transfused in Quixil® versus non-Quixil group were 60 verus 86. Total units of intra-operative blood transfused in Quixil® versus non-Quixil group were 16 versus 23. The use of fibrin tissue adhesive in revision total hip arthroplasty seems to be an effective and reliable means to reduce blood-transfusion requirements and prevent post-operative decreases in hemoglobin.

Validation of the Charlson comorbidity index in patients undergoing revision total hip arthroplasty.

The Charlson comorbidity index (CCI) was developed to quantify the influence of comorbidities on survival. The age-related CCI respects patients' age as an additional risk factor. There are several studies available based on administrative data regarding functional outcome, implant survival, resource use and length of hospital stay in patients undergoing primary total hip arthroplasty (THA). To date, there is a lack of knowledge regarding the correlation of the CCI and the age-related CCI in case of revision total hip arthroplasty (RTHA). Our objective was to validate the influence of the CCI and age-related CCI in patients undergoing RTHA regarding complication rate, resource use implant survival and mortality rate. Between October 2007 and November 2012, 142 consecutive patients undergoing RTHA were included in this retrospective study. Routine clinical data were collected and analysed as anonymized aggregated data. In accordance to CCI and age-related CCI the rate of complications (internal medical and surgical complications), the length of hospital stay and the need for ICU treatment and the mortality rate was evaluated. Kaplan-Meier survivorship was used to determine implant survival. Twenty-one patients (15%) had a low risk CCI, 59 patients (41%) a moderate risk CCI and 62 patients (44%) a high risk CCI. The mean follow-up was 27 months (range 24-70 months). In total, we recorded 57 complications (40%), of which 45 were surgical (79%) and 12 were internal medical complications (21%). Twenty-four patients (17%) had to undergo revision surgery. CCI and age-related CCI had no influence regarding implant survival. We recorded a significant influence of the age-related CCI in regard to the necessity of postoperative intensive care unit stay and the length of total hospital stay. Further we recorded a significant influence of the CCI and the age-related CCI regarding postoperative complications and internal complications, postoperative dislocation and the need for surgical revision. In summary, we conclude that the CCI and the age-related CCI are strong predictors regarding complication rate in patients undergoing RTHA. In a short- to mid-term follow-up, no influence on implant survival is detectable.

Do revision total hip augments provide appropriate modularity?

Porous metal acetabular augments have become widely used to fill bony defects in patients undergoing revision total hip arthroplasty. The objective of this study was to determine whether the currently offered size range of the augments is appropriate for surgical needs. We reviewed the cases of all patients at 1 centre with a porous revision shell, and when an augment was used we recorded the patient and implant characteristics. We reviewed the cases of 281 patients, and augments were used in 24. Augment diameter was skewed toward the small end (p < 0.001), although thickness was not (p = 0.05); 21 of 24 augments were those with the smallest 3 diameters and thicknesses. Given the sizes used, the full range of inventory provided by the manufacturer may be unnecessary, as surgeons will likely attempt a larger shell before a larger augment.