No Difference in Revision Rates or Patient Reported Outcome Measures Between Surgical Approaches for Total Hip Arthroplasty Performed for Femoral Neck Fracture: An Analysis of 5,025 Primary Total Hip Arthroplasties from the New Zealand Joint Registry.

BACKGROUND: Total hip arthroplasty (THA) for femoral neck fracture (FNF) can be performed through different surgical approaches. This study compared the revision rates and patient-reported outcome measures (PROM) by surgical approach. METHODS: Data from the New Zealand Joint Registry (NZJR) were analyzed for patients undergoing primary THA for FNF from January 2000 to December 2021. A total of 5,025 THAs were performed for FNF; the lateral approach was used in 2,499 (49.7%), the posterior in 2,255 (44.9%), and the anterior in 271 (4.3%). The primary outcome measure was the all-cause revision rate. Secondary outcome measures included revision rates for: dislocation, aseptic femoral component loosening, periprosthetic fracture, and infection. Oxford Hip Scores (OHS) were also collected. Age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) score, femoral head size, dual mobility use, femoral fixation, and surgeon experience were assessed as potential confounding variables. RESULTS: There was no difference in the revision rates between lateral and posterior (P = 0.156), lateral and anterior (P = 0.680), or posterior and anterior (P = 0.714) approaches. There was no difference in the reasons for revision between the lateral and posterior approaches or six-month OHS (P = 0.712). There was insufficient data to compare the anterior approach. CONCLUSIONS: There is no difference in the overall revision rates, reasons for revision, or OHS between the lateral and posterior surgical approaches for THA performed for FNF. Insufficient data on the anterior approach is available for an accurate comparison.

A Systematic Review of Data Collection by National Joint Replacement Registries: What Opportunities Exist for Enhanced Data Collection and Analysis?

BACKGROUND: National joint replacement registries assist surgeons and hospitals with guiding decision making and quality of care. The data points collected are essential to interpret and analyze data and to understand confounding variables and other sources of bias, which can impair retrospective observational research. The aim of this study was to review all national joint replacement registries to assess what data points are recorded, and in what manner, for primary and revision total hip arthroplasty (THA) and total knee arthroplasty (TKA) so that improvements can be made to enhance data collection, interpretation, and analysis. METHODS: All national registries were identified through Internet and publication search and contacted to invite participation. Data collection forms for both primary and revision THA and TKA were requested. Data collected were entered into an Excel spreadsheet. RESULTS: The study group for primary and revision THA consisted of 28 national registries, with 26 agreeing to participate. The study group for primary TKA consisted of 27 national registries, with 24 agreeing to participate. Patient identification details were recorded uniformly. Only a minority recorded patient details beyond American Society of Anesthesiologists and body mass index. Most registries did not record surgeon variables: who actually performed or assisted the procedure and their level of training. There was variation in the degree of detail recorded for diagnosis, mostly regarding secondary causes of osteoarthritis and fracture. The details regarding case complexity were limited. Half recorded previous operations, and fewer recorded bone defects. The location of knee arthritis, preoperative limb alignment, and deformities were rarely recorded. Surgical approach and technological adjuncts were routinely collected, but few other details on the surgical technique were recorded. Implant details and fixation were uniformly collected, although a minority recorded specific details, including cement antibiotic or cementing technique. It was uncommon to record whether additional or adjunctive procedures were concurrently performed. Approximately half the registries lacked a revision specific form. The majority recorded reoperations in addition to revision procedures. Patient, surgeon, case, and postoperative details were recorded similar to primary procedures. There was variation in the degree of details recorded for the reasons underlying the revision +/- reoperation, with most recording greater detail for infection and fracture. Many included details on case complexity and bone defects, including the severity, classification, and how the defect was managed. The majority recorded the specific revision procedure that was performed (total or partial), the fixation used, and the components removed or revised. Other specific aspects of fixation including acetabular screws, cone or sleeve use, stems, and augments were less commonly recorded. CONCLUSION: Substantial data are recorded by all registries, although each one is different. Data solicited lack many patient factors, surgeon variables, case complexity, and surgical techniques. Separate revision forms are not universal, and many registries do not record reoperation procedures, specific causes of revision, and the revision construct. LEVEL OF EVIDENCE: Level II, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Do the Revision Rates of Arthroplasty Surgeons Correlate With Postoperative Patient-reported Outcome Measure Scores? A Study From the Australian Orthopaedic Association National Joint Replacement Registry.

BACKGROUND: Patient-reported outcome measures (PROMs) are a pragmatic and efficient means to evaluate the functional quality of arthroplasty beyond revision rates, which are used by most joint replacement registries to judge success. The relationship between these two measures of quality-revision rates and PROMs-is unknown, and not every procedure with a poor functional result is revised. It is logical-although still untested-that higher cumulative revision rates correlate inversely with PROMs for individual surgeons; more revisions are associated with lower PROM scores. QUESTIONS/PURPOSES: We used data from a large national joint replacement registry to ask: (1) Does a surgeon's early THA cumulative percent revision (CPR) rate and (2) early TKA CPR rate correlate with the postoperative PROMs of patients undergoing primary THA and TKA, respectively, who have not undergone revision? METHODS: Elective primary THA and TKA procedures in patients with a primary diagnosis of osteoarthritis that were performed between August 2018 and December 2020 and registered in the Australian Orthopaedic Association National Joint Replacement Registry PROMs program were eligible. THAs and TKAs were eligible for inclusion in the primary analysis if 6-month postoperative PROMs were available, the operating surgeon was clearly identified, and the surgeon had performed at least 50 primary THAs or TKAs. Based on the inclusion criteria, 17,668 THAs were performed at eligible sites. We excluded 8878 procedures that were not matched to the PROMs program, leaving 8790 procedures. A further 790 were excluded because they were performed by unknown or ineligible surgeons or were revised, leaving 8000 procedures performed by 235 eligible surgeons, including 4256 (53%; 3744 cases of missing data) patients who had postoperative Oxford Hip Scores and 4242 (53%; 3758 cases of missing data) patients who had a postoperative EQ-VAS score recorded. Complete covariate data were available for 3939 procedures for the Oxford Hip Score and for 3941 procedures for the EQ-VAS. A total of 26,624 TKAs were performed at eligible sites. We excluded 12,685 procedures that were not matched to the PROMs program, leaving 13,939 procedures. A further 920 were excluded because they were performed by unknown or ineligible surgeons, or because they were revisions, leaving 13,019 procedures performed by 276 eligible surgeons, including 6730 (52%; 6289 cases of missing data) patients who had had postoperative Oxford Knee Scores and 6728 (52%; 6291 cases of missing data) patients who had a postoperative EQ-VAS score recorded. Complete covariate data were available for 6228 procedures for the Oxford Knee Score and for 6241 procedures for the EQ-VAS. The Spearman correlation between the operating surgeon's 2-year CPR and 6-month postoperative EQ-VAS Health and Oxford Hip or Oxford Knee Score was evaluated for THA and TKA procedures where a revision had not been performed. Associations between postoperative Oxford and EQ-VAS scores and a surgeon's 2-year CPR were estimated based on multivariate Tobit regressions and a cumulative link model with a probit link, adjusting for patient age, gender, ASA score, BMI category, preoperative PROMs, as well as surgical approach for THA. Missing data were accounted for using multiple imputation, with models assuming they were missing at random and a worst-case scenario. RESULTS: Of the eligible THA procedures, postoperative Oxford Hip Score and surgeon 2-year CPR were correlated so weakly as to be clinically irrelevant (Spearman correlation ρ = -0.09; p < 0.001), and the correlation with postoperative EQ-VAS was close to zero (ρ = -0.02; p = 0.25). Of the eligible TKA procedures, postoperative Oxford Knee Score and EQ-VAS and surgeon 2-year CPR were correlated so weakly as to be clinically irrelevant (ρ = -0.04; p = 0.004 and ρ = 0.03; p = 0.006, respectively). All models accounting for missing data found the same result. CONCLUSION: A surgeon's 2-year CPR did not exhibit a clinically relevant correlation with PROMs after THA or TKA, and all surgeons had similar postoperative Oxford scores. PROMs, revision rates, or both may be inaccurate or imperfect indicators of successful arthroplasty. Missing data may limit the findings of this study, although the results were consistent under a variety of different missing data scenarios. Innumerable factors contribute to arthroplasty results, including patient-related variables, differences in implant design, and the technical quality of the procedure. PROMs and revision rates may be analyzing two different facets of function after arthroplasty. Although surgeon variables are associated with revision rates, patient factors may exert a stronger influence on functional outcomes. Future research should identify variables that correlate with functional outcome. Additionally, given the gross level of function that Oxford scores record, outcome measures that can identify clinically meaningful functional differences are required. The use of Oxford scores in national arthroplasty registries may rightfully be questioned. LEVEL OF EVIDENCE: Level III, therapeutic study.

Alignment and Fixation in Revision Total Knee Arthroplasty With Press-Fit, Offset, Diaphyseal-Engaging Stem Extensions, and Eccentric Reaming Technique.

BACKGROUND: A revision total knee arthroplasty must control limb alignment, often to address the cause of failure. Press-fit stems that engage the diaphysis with cement restricted to the metaphysis constitute one fixation technique. These long stems restrict coronal alignment of the prosthesis and as a result reduce the likelihood of extreme malposition. For the same reasons, long stems can make it difficult to manipulate alignment and achieve a specific coronal alignment angle. Nevertheless, femoral stems with a tight diaphyseal fit may still occupy a small range of varus-valgus positions due to the conical distal femoral metaphysis. Pulling the reamer toward the lateral endosteum increases femoral component coronal alignment toward a valgus direction and pushing the reamer medially increases alignment in a more varus direction. A straight stem, in combination with a medially directed reaming, would result in a femoral component that overhangs medially, but an offset stem can recenter the femoral component and maintain the desired alignment. We hypothesized that diaphyseal fit plus this reaming technique can control limb coronal alignment and provide fixation. METHODS: This was a retrospective clinical and long-leg radiographic study of consecutive revision total knee arthroplasties with minimum 2-year follow-up. Outcomes were correlated with New Zealand Joint Registry data to identify rerevisions of 111 consecutive revision knee arthroplasties, 92 after exclusions, at a minimum 2-year (range, 2 to 10) follow-up. RESULTS: Mean femoral and tibial canal fill exceeded 91% on antero-posterior and lateral radiographs. The mean hip-knee-ankle angle was 179.6o (174.9-184.0) with 80% within ± 3o of neutral. The hip-ankle axis crossed the central Kennedy zone in 76.5% of cases and the other 24.6% crossed the inner medial and inner lateral zones. Tibial components: 99.0% ± 3o. Femoral components: 89.5% within ± 3o. There were 5 knees that failed due to infection, 3 from femoral loosening, and 1 due to recurvatum instability from polio. CONCLUSIONS: This study describes a surgical plan and technique for achieving target coronal alignment with press-fit diaphyseal fixation. It is the only series of revision knee arthroplasties with diaphyseal press-fit stems to report canal fill in 2 planes and coronal alignment on full-length radiographs.

Is the Revision Rate for Femoral Neck Fracture Lower for Total Hip Arthroplasty Than for Hemiarthroplasty?: A Comparison of Registry Data for Contemporary Surgical Options.

BACKGROUND: When arthroplasty is indicated for a femoral neck fracture (FNF), it is unclear whether total hip arthroplasty (THA) or hemiarthroplasty (HA) is best. This study compares data from the Australian Orthopaedic Association National Joint Replacement Registry using contemporary surgical options. METHODS: Patients from 60 to 85 years old who were treated with arthroplasty for FNF, between September 1999 and December 2019, were included if the femoral stems were cemented. Only THAs with femoral heads of ≥36 mm or dual-mobility articulations were included. Patients who had monoblock HA were excluded. Rates of revision for all aseptic failures and dislocation were compared. Competing risks of revision and death were considered using the cumulative incidence function. Subdistribution hazard ratios (HRs) for revision or death from a Fine-Gray regression model were used to compare THA and HA. Interactions of procedure with age group and sex were considered. Secondary analysis adjusting for body mass index (BMI) and American Society of Anesthesiologists (ASA) classification was also considered. RESULTS: There were 4,551 THA and 29,714 HA procedures included. The rate of revision for THA was lower for women from 60 to 69 years old (HR = 0.58 [95% confidence interval (CI), 0.39 to 0.85]) and from 70 to 74 years old (HR = 0.65 [95% CI, 0.43 to 0.98]) compared with HA. However, women from 80 to 85 years old (HR = 1.56 [95% CI, 1.03 to 2.35]) and men from 75 to 79 years old (HR = 1.61 [95% CI, 1.05 to 2.46]) and 80 to 85 years old (HR = 2.73 [95% CI, 1.89 to 3.95]) had an increased rate of revision when THA was undertaken compared with HA. There was no difference in the rate of revision for dislocation between THA and HA for either sex or age categories. CONCLUSIONS: When contemporary surgical options for FNF are used, there is a benefit with respect to revision outcomes for THA in women who are <75 years old and a benefit for HA in women who are ≥80 years old and men who are ≥75 years old. There is no difference in dislocation rates. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Medial Pivot Designs Versus Conventional Bearing Types in Primary Total Knee Arthroplasty: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Medial pivot (MP) designs are growing in popularity. They provide increased sagittal plane stability and theoretically replicate some aspects of native joint kinematics, which may improve total knee arthroplasty outcomes. METHODS: A systematic review was performed of randomized controlled trials (RCTs) that compared MP designs with cruciate-retaining, posterior-stabilized (PS), ultracongruent, or mobile-bearings in primary total knee arthroplasty, according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The primary outcome measures were all clinical function scores, patient-reported outcome measures, and range of motion. The secondary outcome was complications. Two authors independently selected studies, performed data extraction, and risk-of-bias assessment. Studies at high risk of bias were excluded from meta-analysis. Treatment effects were assessed using random-effects meta-analysis and quantified using pooled mean differences or incidence rate differences as appropriate. RESULTS: Eight RCTs met inclusion criteria. Five compared MP with PS, two with ultracongruent, and one with cruciate-retaining and mobile-bearing. In total, 350 knees were randomized to MP and 375 to conventional bearings. One RCT was excluded from meta-analysis because of high risk of bias. Meta-analysis comparing MP with PS only was possible and found no differences at any time points for any outcome measure, including 2-year follow-up for Oxford Knee Score (MD = 0.35 favoring PS; 95% CI -0.49 to 1.20) and range of motion (MD = 1.58 favoring MP; 95% CI -0.76 to 11.92, P = 0.30) and 12 months for Western Ontario Arthritis Index (MD = 4.42 favoring MP; 95% CI -12.04 to 3.20, P = 0.09). CONCLUSIONS: There is no difference in clinical outcomes, with contemporary measurement tools, at any time points, between MP and PS. There are insufficient RCTs comparing MP with other bearings.

Periprosthetic Joint Infection Is the Main Cause of Failure for Modern Knee Arthroplasty: An Analysis of 11,134 Knees.

BACKGROUND: Although large series from national joint registries may accurately reflect indications for revision TKAs, they may lack the granularity to detect the true incidence and relative importance of such indications, especially periprosthetic joint infections (PJI). QUESTIONS/PURPOSES: Using a combination of individual chart review supplemented with New Zealand Joint Registry data, we asked: (1) What is the cumulative incidence of revision TKA? (2) What are the common indications for revising a contemporary primary TKA? (3) Do revision TKA indications differ at various followup times after primary TKA? METHODS: We identified 11,134 primary TKAs performed between 2000 and 2015 in three tertiary referral hospitals. The New Zealand Joint Registry and individual patient chart review were used to identify 357 patients undergoing subsequent revision surgery or any reoperation for PJI. All clinical records, radiographs, and laboratory results were reviewed to identify the primary revision reason. The cumulative incidence of each revision reason was calculated using a competing risk estimator. RESULTS: The cumulative incidence for revision TKA at 15 years followup was 6.1% (95% CI, 5.1%-7.1%). The two most-common revision reasons at 15 years followup were PJI followed by aseptic loosening. The risk of revision or reoperation for PJI was 2.0% (95% CI, 1.7%-2.3%) and aseptic loosening was 1.2% (95% CI, 0.7%-1.6%). Approximately half of the revision TKAs secondary to PJI occurred within 2 years of the index TKA (95% CI, 0.8%-1.2%), whereas half of the revision TKAs secondary to aseptic loosening occurred 8 years after the index TKA (95% CI, 0.4%-0.7%). CONCLUSIONS: In this large cohort of patients with comprehensive followup of revision procedures, PJI was the dominant reason for failure during the first 15 years after primary TKA. Aseptic loosening became more important with longer followup. Efforts to improve outcome after primary TKA should focus on these areas, particularly prevention of PJI. LEVEL OF EVIDENCE: Level III, therapeutic study.

Higher cefazolin concentrations with intraosseous regional prophylaxis in TKA.

BACKGROUND: Prophylactic antibiotics reduce the risk of deep infection after primary TKA. However, conventional systemic dosing may not provide adequate tissue concentrations against more resistant organisms such as coagulase-negative staphylococci. Regional intravenous administration of antibiotics after tourniquet inflation achieves far higher tissue concentrations but requires foot vein cannulation. The intraosseous route may offer a rapid and reliable method of regional administration. QUESTIONS/PURPOSES: We compared tissue concentrations of cefazolin achieved with systemic versus regional intraosseous administration. METHODS: Twenty-two patients undergoing primary TKA were randomized into two groups. Group 1 received 1 g cefazolin systemically 10 minutes before tourniquet inflation. Group 2 received 1 g cefazolin intraosseously in 200 mL of normal saline through a tibial cannula after tourniquet inflation and before skin incision. Subcutaneous fat and femoral bone samples were taken at set intervals during the procedure and antibiotic concentrations measured using a validated technique involving high-performance liquid chromatography. RESULTS: The overall mean tissue concentration of cefazolin in subcutaneous fat was 186 ug/g in the intraosseous group and 11 ug/g in the systemic group. The mean tissue concentration in bone was 130 ug/g in the intraosseous group and 11 ug/g in the systemic group. These differences were consistent across all sample time points throughout the procedure. CONCLUSIONS: Intraosseous regional administration can achieve concentrations of antibiotic in tissue an order of magnitude higher than systemic administration. Further work is required to determine if this translates into increased efficacy in preventing infection, particularly against coagulase-negative staphylococci.

Diagnosis and management of patients with instability of the knee.

Instability of a total knee arthroplasty is a fundamentally different problem from instability of the knee without an arthroplasty. Revision surgery to correct the inciting forces will usually be necessary, and ligament reconstruction alone is usually unsuccessful. Because it may be the presenting complaint for any of the usual conditions that require revision arthroplasty, instability as reported by a patient should be considered a symptom that requires detailed evaluation rather than immediate surgery. Evaluation should be systematic and comprehensive, meaning that the same algorithm or system should be applied to all knee arthroplasties, and all diagnostic entities should be considered. There are several common types of instability, each requiring a different surgical strategy. Any dysfunction of the extensor mechanism, including pain inhibition (even from the ipsilateral hip) may result in buckling. Structural recurvatum, often originating from relative quadriceps weakness, may require arthrodesis if extensor function is completely absent. Varus or valgus instability will require stabilization in the form of constrained implants, with or without ligament releases, advancements, or substitution. Realignment will almost always be advantageous. Flexion instability is invariably linked to flexion gaps that are larger or more lax than the extension gap, requiring revision with attention to gap balance, and in many cases, some degree of mechanically constrained devices. Arthritic knee joints in obese patients and those with severe angular deformity or fixed flexion contractures are at particular risk for instability after total knee arthroplasty. Instability that becomes apparent intraoperatively is a challenging condition, particularly when there is no immediate recourse to using constrained implants.

Internal rotation of the tibial component is frequent in stiff total knee arthroplasty.

BACKGROUND: Stiffness complicating TKA is a complex and multifactorial problem. We suspected internally rotated components compromised motion because of pain, patellar maltracking, a tight medial flexion gap, and limited femoral rollback on a conforming lateral tibial condyle. QUESTIONS/PURPOSES: We sought to determine: (1) the incidence of internal rotation of the femoral and tibial components in stiff TKAs; (2) if revision surgery that included correction of rotational positioning improved pain, ROM, and patellar tracking; and (3) if revision altered nonrotational radiographic parameters. METHODS: From a cohort of 52 patients with TKAs revised for stiffness, we performed CT scans of 34 before and 18 after revision to quantify rotational positioning of the femoral and tibial components using a previously validated scanning protocol. RESULTS: All 34 patients with TKAs had internal rotation of the summed values for tibial and femoral components (mean, 14.8°; range, 2.7°-33.7°) before revision for stiffness. The incidence of internal rotation was 24 of 34 femoral (mean, 3.1°; internal) and 33 of 34 tibial components (mean, 13.7° internal). Revision arthroplasty improved Knee Society function, knee, and pain scores. Mean extension improved from a contracture of 10.1° to 0.8° and flexion from 71.5° to 100°. Postrevision CT scans confirmed correction of component rotation. Nonrotational parameters were unchanged. CONCLUSIONS: We recommend CT scanning of patients with stiff TKAs before surgical intervention to identify the presence of internally rotated components. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Fifteen-year to 19-year follow-up of the Insall-Burstein-1 total knee arthroplasty.

This represents a 15-year to 19-year follow-up of 100 Insall-Burstein-I posterior-stabilized knee prostheses implanted in 86 patients from 1986 to 1989 and originally reported at 10 to 12 years (Thadani et al, 2000). In the original cohort, 6 failures occurred by 10 years. At 15 to 19 years, 55 patients (66 knees) had died; 18 patients were followed with clinical examination and radiographs, and 11 by telephone; 3 knees in 2 patients were lost. There were no new failures or additional surgeries from 10 to 19 years. Three knees exhibited osteolytic lesions. No case required revision due to symptomatic osteolysis or polyethylene wear. Using revision as end point, survival was 92.4% at 19 years. In summary, the prosthesis is likely to outlive the patients when classic indications for age and activity are respected.

New concepts in revision total knee arthroplasty.

Revision knee arthroplasty should be regarded as a discipline separate from primary surgery. A disciplined approach to diagnosis is mandatory in which the following categories for failure are useful: (a) sepsis, (b) extensor mechanism rupture, (c) stiffness, (d) instability, (e) periprosthetic fracture, (f) aseptic loosening and osteolysis, (g) patellar complications and malrotation, (h) component breakage, and (i) no diagnosis. In the event of no coherent explanation for pain and disability, the possibilities of chronic regional pain syndrome, hip or spine pathology, and inability of current technology to meet patient expectations should be considered and revision surgery should be avoided. Revision arthroplasty cannot be performed as if it were a primary procedure and indeed will be eight (or more) different surgeries depending on the cause of failure. Though perhaps counterintuitive, there is a logical rationale and empirical evidence to support complete revision in virtually every case. In general, revision implant systems are required. The early dependence on the "joint line" is inadequate, failing as it does to recognize that the level of the articulation is a three-dimensional concept and not simply a "line." The key to revision surgery technique is that the flexion gap is determined by femoral component size and the extension gap by proximal distal component position. Accordingly, a general technical pathway of three steps can be recommended: 1) tibial platform; 2) stabilization of the knee in flexion with (a) femoral component rotation and (b) size selected with evaluation of (c) patellar height as an indication of "joint line" in flexion only; and 3) stabilization of the knee in extension, an automatic step. Stem extensions improve fixation and, if they engage the diaphysis, may be used as a guide for positioning. Porous metals designed as augments for bone defects may prove more important as "modular fixation interfaces." It is postulated that with the exception of septic and extensor mechanism complications, first revision knee arthroplasty may exceed the durability of primary knee arthroplasty.

Component alignment in revision total knee arthroplasty using diaphyseal engaging modular offset press-fit stems.

We performed a retrospective study of the radiographic position of femoral and tibial components in a series of revision total knee arthroplasties using diaphyseal-engaging, press fit, modular stems. Fifty-two consecutive revision cases were performed. Femoral and tibial component alignment was measured preoperatively and postoperatively. The canal-filling ratio was measured and correlated with anatomic alignment. There was a trend toward improved alignment with increasing canal fill, suggesting that uncemented diaphyseal engaging press-fit modular stems facilitate accurate alignment for both femoral and tibial components in revision surgery.