Obesity Severity Predicts Patient Dissatisfaction After Total Knee Arthroplasty

BACKGROUND

Patient dissatisfaction has been reported in 15 to 20% of traditional total knee arthroplasty (TKA) procedures. While contemporary improvements may have positive effects on patient satisfaction, these may be offset by increasing obesity prevalence among patients who have knee osteoarthritis. We performed this study to determine whether obesity severity impacts patient-reported TKA satisfaction.

METHODS

We compared patient demographic characteristics, preoperative expectations, preoperative and minimum 1-year postoperative patient-reported outcome measures as well as postoperative satisfaction level among 229 patients (243 TKAs) who had World Health Organization (WHO) Class II or III obesity (group A), and 287 patients (328 TKAs) who had WHO classifications of normal weight, overweight, or Class I obesity (group B).

RESULTS

Group A patients were younger and had more severe preoperative back and contralateral knee pain, more frequent preoperative opioid medication use, and lower preoperative and postoperative patient-reported outcome measures (P < .01). A similar proportion of patients in both groups expected at least 75% improvement (68.5 versus 73.2%, P = .27). While satisfaction was higher than traditional reporting for both groups (89.4 versus 92.6%, P = .19), group A patients were less likely to be highly satisfied (68.1 versus 78.5%, P = .04) and were more likely to be highly dissatisfied (5.1 versus 0.9%, P < .01).

CONCLUSIONS

Patients who have Class II and III obesity report greater TKA dissatisfaction. Additional studies should help determine whether specific implant designs or surgical techniques may improve patient satisfaction or whether preoperative counseling should incorporate lower satisfaction expectations for patients who have WHO Class II or III obesity.

Outcomes of Total Knee Arthroplasty Revisions in Obese and Morbidly Obese Patient Populations

BACKGROUND

The obese population is at higher risk for complications following primary total knee arthroplasty (TKA), but little data is available regarding revision outcomes. This study aimed to investigate the role of body mass index (BMI) in the cause for revision TKA and whether BMI classification is predictive of outcomes.

METHODS

A multi-institutional database was generated, including revision TKAs from 2012 to 2019. Data collection included demographics, comorbidities, surgery types (primary revision, repeat revision), reasons for revision, lengths of hospital stay, and surgical times. Patients were compared using 3 BMI categories: nonobese (18.5 to 29.9), obese (30 to 39.9), and morbidly obese (≥40). Categorical and continuous variables were analyzed using chi-square and 1-way analysis of variance tests, respectively. Regression analyses were used to compare reasons for revision among weight classes.

RESULTS

Obese and morbidly obese patients showed significant risk for repeat revision surgery in comparison to normal weight patients. Obese patients were at higher risk for primary revision due to stiffness/fibrosis and repeat revision due to malposition. In comparison to the obese population, morbidly obese patients were more likely to require primary revision for dislocation and implant loosening.

CONCLUSION

Significant differences in primary and repeat revision etiologies exist among weight classes. Furthermore, obese and morbidly obese patients have a greater risk of requiring repeat revision surgery. These patients should be informed of their risk for multiple operations, and surgeons should be aware of the differences in revision etiologies when anticipating complications following primary TKA.

Conversion Total Knee Arthroplasty after Failed Osteochondral Allograft Reconstruction: Similar Functional Performance with Lower Patient Satisfaction

BACKGROUND

This study presents surgical techniques used in conversion total knee arthroplasty (cTKA) following early failure of large osteochondral allograft joint replacement and compares postoperative patient reported outcomes measures (PROMs) and satisfaction scores with a contemporary primary total knee arthroplasty (pTKA) cohort.

METHODS

We retrospectively evaluated 25 consecutive cTKA patients (26 procedures) to define utilized surgical techniques, radiographic disease severity, preoperative and postoperative PROMs (visual analog scale (VAS) pain, knee injury and osteoarthritis outcome score for joint replacement (KOOS-JR), University of California Los Angeles (UCLA) Activity), expected improvement and postoperative satisfaction (5-point Likert), and reoperations in comparison with an age and body mass index (BMI) propensity matched cohort of 50 pTKA performed for osteoarthritis (52 procedures).

RESULTS

Revision components were used in 12 cTKA cases (46.1%), with 4 cases requiring augmentation (15.4%), and 3 cases utilizing varus-valgus constraint (11.5%). While no significant differences were noted in expectation level or in other PROMs, mean patient reported satisfaction was lower in the conversion group (4.4 +/- 1.1 vs 4.8 +/- 0.5 points, P=0.02). High cTKA satisfaction was associated with higher postoperative KOOS-JR (84.4 vs 64.2 points, P=0.01) and trend towards higher UCLA activity (6.9 vs 5.7 points, P=0.08). Four patients in each group underwent manipulation (15.3 vs 7.6%, P=0.42), and one primary TKA patient was treated for early postoperative infection (0 vs 1.9%, P=1.0).

CONCLUSION

Conversion TKA following failed biological replacement was associated with similar postoperative improvement as in pTKA. Lower patient reported cTKA satisfaction was associated with lower postoperative KOOS-JR scores.

Tobacco Use Is Associated with More Severe Adverse Outcomes Than Morbid Obesity after Aseptic Revision TKA

The association of morbid obesity with increased revision total knee arthroplasty (rTKA) complications is potentially confounded by concurrent risk factors. This study was performed to evaluate whether morbid obesity was more strongly associated with adverse aseptic rTKA outcomes than diabetes or tobacco use history-when present as a solitary major risk factor. Demographic characteristics, surgical indications, and adverse outcomes (reoperation, revision, infection, and amputation) were compared between 270 index aseptic rTKA performed for patients with morbid obesity (n = 73), diabetes (n = 72), or tobacco use (n = 125) and 239 "healthy" controls without these risk factors at a mean 75.7 (range: 24-111) months. There was no difference in 2-year reoperation rate (17.8 vs. 17.6%, p = 1.0) or component revision rate (8.2 vs. 8.4%) between morbidly obese and healthy patients. However, higher reoperation rates were noted in patients with diabetes (p = 0.02) and tobacco use history (p < 0.01), including higher infection (p < 0.05) and above knee amputation (p < 0.01) rates in patients with tobacco use history. Multivariate analysis retained an independent association between smoking history and amputation risk (odds ratio: 7.4, 95% confidence interval: 1.7-55.2, p < 0.01). Morbid obesity was not associated with an increased risk of reoperation or component revision compared with healthy patients undergoing aseptic revision. Tobacco use was associated with increased reoperation and above knee amputation. Additional study will be beneficial to determine whether risk reduction efforts are effective in mitigating postoperative complication risks.

Dual Antibiotic Prophylaxis in Primary Total Knee Arthroplasty-No Benefit for Extremely Obese Patients

We performed this study to assess the effectiveness of multimodal total knee arthroplasty prosthetic joint infection (TKA-PJI) prophylaxis including "on-time" dual-antibiotic prophylaxis, and the influence of body mass index (BMI) on prophylaxis effectiveness. After obtaining Institutional Review Board approval, we assessed 1,802 primary TKAs (1,496 patients) who received cefazolin alone or cefazolin combined with vancomycin for TKA-PJI prophylaxis. A detailed chart review was performed to determine patient demographic features (age, gender, BMI, American Society of Anesthesiologists Score), antibiotic selection, vancomycin administration timing, and 1-year PJI rates. Statistical assessment was accomplished using a two-sided Student's t-test or Fisher's exact test. Patients who received dual-antibiotic prophylaxis with "on time" vancomycin infusion (Group CVt) had significantly lower infection rates than other TKA patients (0.8 vs. 2.7%, p < 0.01). "On Time" vancomycin administration was associated with a lower TKA-PJI rate for patients with a BMI < 45 kg/m² (0.5 vs. 2.6%, p < 0.01) with no infections in 120 TKA patients with a BMI between 40 and 44.9 kg/m² (p < 0.01). No difference was noted for patients with a BMI ≥ 45 kg/m² (3.3 vs. 2.6%, p = 0.71). There were no infections in 150 TKA patients with a normal BMI (18-25 kg/m²) in any PJI-prophylaxis treatment group. Adoption of a dual-antibiotic prophylaxis approach can successfully reduce TKA-PJI rates among overweight and moderately obese patients. The approach does not appear to influence outcomes for low risk patients with a normal BMI (18-25 kg/m²) or for higher risk patients with a BMI > 45 kg/m².

Revision TKA for Instability: Poorer Outcomes after a Previous Aseptic Revision

Instability is a common indication for early revision total knee arthroplasty (rTKA). The comparative performance of instability rTKA performed after primary TKA and instability rerevision TKA (rrTKA) performed after a previous rTKA performed for any aseptic indication have not been defined. This study was performed to determine the rate of adverse outcomes for patients undergoing aseptic instability TKA revision following a primary TKA or a previous aseptic any-cause rTKA. After obtaining Institutional Review Board approval, we retrospectively identified 126 rTKA and 28 rrTKA component revision procedures performed for an exclusive instability diagnosis between January 1, 2011 and April 30, 2018. We excluded patients undergoing isolated liner exchange, single component revision for mid-flexion instability, and patients treated with a constrained hinge. Patient demographic characteristics, medical comorbidities, time to initial revision TKA, and adverse postrevision outcomes (reoperation, component revision, infection, amputation) were assessed using paired Student's t-test or Fisher's exact test with a p-value < 0.05 used to determine significance. Patients in the rrTKA cohort were more commonly female (57.1 vs. 27.8%, p < 0.01), with no other demographic differences. The rrTKA cohort had higher reoperation (39.3 vs. 18.4%, p = 0.02) and component revision rates (25.0 vs. 8.7%, p = 0.03), with a trend towards early reoperation < 2 years after surgery (25.0 vs. 11.1%, p = 0.07). The rrTKA cohort also had higher adverse outcomes related to infection (14.3 vs. 1.6%, p = 0.01), extensor mechanism failure (14.3 vs. 3.2%, p = 0.04) and above-knee amputation (14.3 vs. 2.4%, p = 0.02). Component revision is beneficial for patients with TKA instability; however, higher adverse outcome rates occur after instability rrTKA performed after a previous aseptic any-cause rTKA. Infection prevention and extensor mechanism protection are important to minimize the most common adverse outcomes identified among patients undergoing aseptic rrTKA for instability.

Cemented Patellar Implant Malposition: A Non-Issue for the Painful Total Knee Arthroplasty

BACKGROUND

Non-optimal patellofemoral relationships may influence treatment decisions during revision total knee arthroplasty (TKA). We performed this study to determine whether patellar implant malposition or patellar tilt is associated with inferior patient-reported outcome scores or patient satisfaction after primary TKA.

METHODS

We identified 396 TKA patients (439 knees) from an institutional registry who had undergone patellar resurfacing, with preoperative and 6-week postoperative radiographs available, and patient-reported outcome measures (PROMs) completed at least 1 year after surgery (mean 505 days). Preoperative patient demographic characteristics, patient-reported expectations, National Institutes of Health - Patient Reported Outcomes Measurements Instrument Systems global health, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, and University of California Los Angeles activity scores were compared between 60 TKAs performed with non-optimal patellofemoral relationships (36 patellar implant malposition, 24 patellar tilt) and 379 TKAs performed with optimal patellar implant placement.

RESULTS

There were no differences between the 2 cohorts regarding demographic features, preoperative radiographic disease severity, expectations, and PROMs; or postoperative tibiofemoral component alignment, PROMs, and patient-reported satisfaction (P = .48). Knee Injury and Osteoarthritis Outcome Score for Joint Replacement improved similarly (P = .62) for patients with optimal resurfacing (48.5-77.6 points) and non-optimal resurfacing (47.7-76.6 points). A similar proportion of optimal and suboptimal resurfaced patients reported being satisfied with their TKA (92.7% vs 88.1%, P = .29).

CONCLUSION

Although suboptimal patellofemoral relationships may prompt treatment considerations during revision TKA, the data obtained from this study do not suggest that patellar implant malposition or patellar tilt independently contribute to postoperative pain, functional limitation, or dissatisfaction.

LEVEL OF EVIDENCE

This is a level III, retrospective cohort study.

Isolated Liner Revision for Total Knee Arthroplasty Instability: A Road That Should Remain Less Taken

Isolated polyethylene liner exchange (IPLE) is infrequently selected as a treatment approach for patients with primary total knee arthroplasty (TKA) prosthetic joint instability. Potential advantages of less immediate surgical morbidity, faster recovery, and lower procedural cost need to be measured against reoperation and re-revision risk. Few published studies have directly compared IPLE with combined tibial and femoral component revision to treat patients with primary TKA instability. After obtaining institutional review board (IRB) approval, we performed a retrospective comparison of 20 patients treated with IPLE and 126 patients treated with tibial and femoral component revisions at a single institution between 2011 and 2018. Patient demographic characteristics, medical comorbidities, time to initial revision TKA, and reoperation (90 days, <2 years, and >2 years) were assessed using paired Student's t-test or Fisher's exact test with a p-value <0.01 used to determine significance. Patients undergoing IPLE were more likely to undergo reoperation (60.0 vs. 17.5%, p = 0.001), component revision surgery (45.0 vs. 8.7%, p = 0.002), and component revision within 2 years (30.0 vs. 1.6%, p < 0.0001). Differences in 90-day reoperation (p = 0.14) and revision >2 years (p = 0.19) were not significant. Reoperation for instability (30.0 vs. 4.0%, p < 0.001) and infection (20.0 vs. 1.6%, p < 0.01) were both higher in the IPLE group. IPLE does not provide consistent benefits for patients undergoing TKA revision for instability. Considerations for lower immediate postoperative morbidity and cost need to be carefully measured against long-term consequences of reoperation, delayed component revision, and increased long-term costs of multiple surgical procedures. This is a level III, case-control study.

Tibial Bone Quality in Former Bariatric Surgery Patients with Osteoarthritis

Downstream effects of bariatric weight-loss surgery have been associated with bone resorption, potentially jeopardizing total knee arthroplasty (TKA) implant fixation/ingrowth.

PURPOSE

This case-control study sought to determine if TKA patients with history of bariatric surgery exhibit altered microanatomy of subchondral bone quality in the tibial plateau compared to controls.

MATERIALS AND METHODS

With IRB approval, 41 bone samples were evaluated from 12 former bariatric surgery patients and 10 sex-, age-, weight-, height-, and BMI-matched controls. Patient-Reported Outcomes Measurement Information System (PROMIS) surveys were completed prior to TKA. Tibial plateau osteochondral tissues were recovered during the TKA procedure, and samples from the medial and lateral plateaus were dissected into 1 × 2 cm sections, scanned using microcomputed tomography (µCT), and plastic-embedded for histologic sectioning/staining of undecalcified bone. Paired t tests with Bonferroni correction were performed to assess group differences.

RESULTS

Female bariatric surgery patients had reduced osteoid/total area and greater osteoclast number asymmetry than female controls (p < 0.03). No differences were noted in µCT or histologic bone parameters between bariatric and control patients when the sexes were combined. Bariatric patients self-reported worse preoperative PROMIS pain interference and physical function scores than controls (p < 0.04).

CONCLUSIONS

Similarities of subchondral bone between former bariatric surgery patients and matched controls indicate OA disease progression dominates the bone landscape in both patient groups.

Bacterial DNA screening to characterize surgical site infection risk in orthopaedic patients

Purpose

To provide an initial characterization of relevant bacterial DNA profiles for patients undergoing closed-fracture fixation or total joint arthroplasties.

Patients and methods

Swabs were collected and analyzed using Polymerase Chain Reaction from adult patients undergoing closed-fracture fixation or total shoulder, knee, or hip arthroplasties.

Results

Bacterial DNA profiles varied across the different orthopaedic patient populations, and produced uncharacteristic profile shifts with direct relevance to each clinical infection.

Conclusion

Findings provide a foundational dataset regarding bacterial colonization of relevant anatomic sites that can act as sources of surgical site infections for patients.

Higher Component Malposition Rates with Patient-Specific Cruciate Retaining TKA than Contemporary Posterior Stabilized TKA

Customized individually manufactured total knee arthroplasty (CIM-TKA) was developed to improve kinematic total knee arthroplasty (TKA) performance. Component placement accuracy may influence the success of CIM-TKA designs. We performed this study to compare radiographic component alignment and revision rates of a cruciate retaining (CR) CIM-TKA and a contemporary posterior stabilized TKA (PS-TKA). After obtaining Institutional Review Board approval, we identified 94 CR CIM-TKAs (76 patients) and 91 PS-TKAs (82 patients) performed between July 1, 2013 and December 31, 2014 with a minimum 2-year follow-up (mean 41.1 months, range 24-59 months). We performed a retrospective electronic medical record review to identify patient demographic characteristics and revision procedures performed. Postoperative plain radiographs were reviewed to assess component alignment including cruciate ligament imbalance, femoral overhang, and femoral notching. Demographic characteristics, component malalignment, and revision surgery rates were assessed using a student's t-test or two-tailed Fisher's exact test, with a p-value < 0.05 designating significance. Technical errors were more commonly identified with CR CIM-TKA (29.8 vs. 9.9%, p < 0.001), including higher rates of tibiofemoral instability (13.8 vs. 1.1%, p < 0.01), femoral notching (12.8 vs. 3.3%, p = 0.03), and patellofemoral malalignment (20.2 vs. 7.7%, p = 0.02). CR CIM-TKA had more frequent coronal plane malposition (26.6 vs. 9.9%, p < 0.01) or sagittal plane reconstruction > 3 degrees outside of an optimized range (20.2 vs. 9.9%, p = 0.06). Aseptic revisions occurred more frequently with the CR CIM-TKA design (9.6 vs. 3.3%, p = 0.13). Demographic characteristics were not significantly different between the treatment groups. CR CIM-TKA may improve kinematic performance for patients undergoing knee replacement surgery. However, our study observations suggest that careful attention to surgical technique is important for optimizing implant survivorship with the CR CIM-TKA design. Additional study is needed to determine whether higher revision rates identified during this study are related to patient selection, surgical technique, or implant design.

TKA is More Durable Than UKA for Morbidly Obese Patients: A Two-Year Minimum Follow-Up Study

BACKGROUND

Unicompartmental knee arthroplasty (UKA) indications have expanded during the past two decades to include some morbidly obese patients (body mass index (BMI) > 40 kg/m²). Few published studies have compared UKA and total knee arthroplasty (TKA) in this unique patient subgroup with conflicting observations.

METHODS

We retrospectively compared 89 mobile bearing UKA (71 patients) and 201 TKA (175 patients) performed at a single institution with a minimum 2-year follow-up (mean 3.4 years). Demographic characteristics were similar for both patient cohorts. A detailed medical record review was performed to assess the frequency of component revision, revision indications, minor secondary procedures (components retained), and infections.

RESULTS

UKA was more frequently associated with clinical failure (29.2% vs 2.5%, P < .001) and component revision (15.7% vs 2.5%, P < .001), TKA was more frequently associated with extensor mechanism complications or knee manipulation (5.5% vs 0.0%, P = .02), and there was no difference in the infection rate (3.0% vs 2.2%, P = 1.0).

CONCLUSION

Early complications were lower following UKA but were outweighed by higher component revision rates for arthritis progression and implant failure. The study findings suggest that TKA provides a more predictable mid-term outcome for morbidly obese patients considering knee arthroplasty surgery.

Characterizing correlations among disease severity measures in osteochondral tissues from osteoarthritic knees

Osteoarthritis (OA) is a complex disease with biologic, biomechanical, and clinical heterogeneity among patients. Relationships among OA tissue metabolism, histopathology, and extracellular matrix (ECM) composition have not been well characterized. It was hypothesized that moderate (r = .4-.69) to strong (r > .7) correlations exist among these different measures of disease severity in osteochondral tissues from OA knees. Joint surfaces were obtained from patients (n = 6) undergoing total knee arthroplasty. Osteochondral explants (n = 136) were created and cultured for 3 days. Culture media were collected for biomarker analyses, and tissue was assessed for viability, histological scoring, and ECM composition. Correlations among media biomarker concentrations, histological scoring, ECM composition, and viability were determined using a Spearman correlation. GRO-α, IL-6, IL-8, and MCP-1 showed strong positive correlations to each other, and moderate positive correlations to NO, PGE2, and MMP-2. Total MMP activity, MMP-9, and MMP-13 had strong positive correlations to each other, and moderate positive correlations to MMP-1. MMP-2 had a moderate to strong positive correlations to histological scores (total and cartilage structure) and collagen content. MMP-2, IL-6, IL-8, and MCP-1 had moderate negative correlations, and MMP-9 had a moderate positive correlation, to viability. GRO-α, IL-6, IL-8, and MCP-1 had moderate positive correlations to collagen content. MMP-9, MMP-13, and total MMP activity had moderate negative correlations to tissue GAG. The data suggest links among proinflammatory and degradative pathways are present in OA osteochondral tissues. Further characterization of these links have the potential to delineate mechanisms of disease and diagnostic and therapeutic targets for knee OA.

Revision Total Knee Arthroplasty in Young Patients: Higher Early Reoperation and Rerevision

BACKGROUND

Revision total knee arthroplasty (rTKA) rates are increasing in younger patients. Few studies have assessed outcomes of initial aseptic rTKA performed for younger patients compared with traditional-aged patients.

METHODS

A detailed medical record review was performed to identify patient demographics, medical comorbidities, surgical rTKA indications, timing from index TKA to rTKA, subsequent reoperation rates, component rerevision rates, and salvage procedures for 147 young patients (158 knees) aged 55 years and younger and for a traditional older cohort of 276 patients (300 knees) between 60 and 75 years. Univariate analysis was performed to assess differences in these primary variables, and a log-rank test was used to estimate 5-year implant survival based on either reoperation or component revision and salvage procedures.

RESULTS

Younger TKA patients were more likely to undergo initial aseptic rTKA within 2 years of their primary TKA (52.5% vs 29.0%, P < .001) and were more likely to undergo early reoperation (17.7% vs 9.7%, P = .02) or component rerevision (11.4% vs 6.0%, P < .05) after rTKA. Infection and extensor mechanism complications were more commonly noted in younger patients. Estimated 5-year survival was also lower for both reoperation (59.4% vs 65.7%, P = .02) and component rerevision or salvage (65.8% vs 80.1%, P = .02).

CONCLUSION

Early reoperation and component re-rTKA were performed nearly twice as often in younger rTKA than traditional-aged TKA patients. Care should be given to reduce perioperative infection and extensor mechanism failures after rTKA in younger patients.

The Past, Present, and Future of Orthopedic Education: Lessons Learned From the COVID-19 Pandemic

The COVID-19 global pandemic has upended nearly every medical discipline, dramatically impacted patient care and has had far-reaching effects on surgeon education. In many areas of the country, elective orthopedic surgery has completely stopped to ensure that resources are available for the critically ill and to minimize the spread of disease. COVID-19 is forcing many around the world to re-evaluate existing processes and organizations and adapt to carry out business, of which medicine and education are not immune. Most national and international orthopedic conferences, training programs, and workshops have been postponed or canceled, and we are now critically evaluating the delivery of education to our colleagues as well as residents and fellows. This article describes the evolution of orthopedic education and significant paradigm shifts necessary to continue to teach ourselves and the future leaders of our noble profession.

High Failure Rates for Unicompartmental Knee Arthroplasty in Morbidly Obese Patients: A Two-Year Minimum Follow-Up Study

BACKGROUND

Several recent studies have recommended offering unicompartmental knee arthroplasty (UKA) to all patients regardless of body mass index (BMI). The aim of this investigation was to evaluate the proposition that UKA can indeed be offered to the morbidly-obese and super-obese (morbidly-obese, BMI ≥ 40 kg/m²) without compromising results or survivorship.

METHODS

We retrospectively reviewed mobile-bearing medial UKA procedures performed at our facility from January 2012 to May 2015 with a minimum of 2-year follow-up. The study cohort was divided into patients with morbid obesity (BMI ≥ 40 kg/m²) and those without morbid obesity (BMI < 40 kg/m²). A detailed medical record review was performed. Extracted outcome data included the frequency of (1) major revision procedures (components revised), (2) minor secondary procedures (components not revised), (3) infection procedures, and (4) recommendations for revision.

RESULTS

We found 152 patients (190 knees) who met criteria for inclusion. Mean follow-up duration was 3.4 years (range: 2.0-6.8 years). Major revision surgery occurred more frequently in the morbid-obesity UKA group (15.7% vs 3.0%, P < .01). Rates of minor secondary surgery and infection were comparable for both groups. Most failures in the morbid-obesity UKA group (85.7%) were due to disease progression involving other compartments or mobile-bearing instability.

CONCLUSION

We found the rate of early major revision surgery in morbidly-obese patients undergoing UKA to be over 5-times greater than that of other patients. Failure was predominantly due to disease progression in other compartments or mobile-bearing instability. Further study is warranted and needed before expanding UKA indications to the morbidly-obese population.

Femoral Component Malrotation Produces Quadriceps Weakness and Impaired Ambulatory Function following Total Knee Arthroplasty: Results of a Forward-Dynamic Computer Model

Proper placement of the prosthetic components is believed to be an important factor in successful total knee arthroplasty (TKA). Implant positioning errors have been associated with postoperative pain, suboptimal function, and inferior patient-reported outcome measures. The purpose of this study was to investigate the biomechanical effects of femoral component malrotation on quadriceps function and normal ambulation. For the investigation, publicly available data were used to create a validated forward-dynamic, patient-specific computer model. The incorporated data included medical imaging, gait laboratory measurements, knee loading information, electromyographic data, strength testing, and information from the surgical procedure. The ideal femoral component rotation was set to the surgical transepicondylar axis and walking simulations were subsequently performed with increasing degrees of internal and external rotation of the femoral component. The muscle force outputs were then recorded for the quadriceps musculature as a whole, as well as for the individual constituent muscles. The quadriceps work requirements during walking were then calculated for the different rotational simulations. The highest forces generated by the quadriceps were seen during single-limb stance phase as increasing degrees of femoral internal rotation produced proportional increases in quadriceps force requirements. The individual muscles of the quadriceps displayed different sensitivities to the rotational variations introduced into the simulations with the vastus lateralis showing the greatest changes with rotational positioning. Increasing degrees of internal rotation of femoral component were also seen to demand increasing quadriceps work to support normal ambulation. In conclusion, internal malrotation of the femoral component during TKA produces a mechanically disadvantaged state which is characterized by greater required quadriceps forces (especially the vastus lateralis) and greater quadriceps work to support normal ambulation.

Incisional Negative Pressure Wound Therapy Devices Improve Short-Term Wound Complications, but Not Long-Term Infection Rate Following Hip and Knee Arthroplasty

BACKGROUND

The potential value of incisional negative pressure wound therapy (iNPWT) on lower extremity total joint arthroplasty (TJA) wound healing has been supported in a few retrospective studies. We performed this prospective, randomized, controlled trial to assess the impact of iNPWT on wound appearance, early complications, and late infection rates following hip and knee TJA compared with a standard surgical dressing.

METHODS

Three-hundred ninety-eight patients undergoing primary or revision lower extremity TJA were randomized into iNPWT or conventional wound dressing groups. Wound healing and early complication rates were assessed at 7, 14, and 35 days after the index surgery. Late infection rates were determined at a mean 2-year follow-up.

RESULTS

Patients treated with an iNPWT device were more likely to report wound drainage at day 7 (P = .01), but less drainage longer than 14 days (P = .04). Wound drainage was significantly higher for total hip arthroplasty patients at day 7 (P = .04), but differences were not sustained through the other time intervals. Total knee arthroplasty patients with a body mass index > 35 kg/m² treated with an iNPWT device experienced fewer complications (1.3% vs 21.6%, P < .01) and fewer dressing-related concerns (1.3% vs 10.8%, P = .02) compared with a conventional dressing. No significant difference in late superficial or deep infection rates was identified between iNPWT and conventional dressing groups (4.0% vs 3.4%, P = .8).

CONCLUSION

Our study findings support improved soft tissue healing response with the use of iNPWT devices. While postoperative wound drainage may limit their value following total hip arthroplasty, incisional NPWT devices may have a targeted benefit for elective total knee arthroplasty patients with a body mass index > 35 kg/m². Specific study in this higher-risk patient group may be helpful to define the value of iNPWT.

Mentorship in Orthopedics: A National Survey of Orthopedic Surgery Residents

OBJECTIVE

Mentorship is an important component of graduate medical education. It has been associated with numerous benefits including personal development, increased career satisfaction, and reduced stress and burnout. The purpose of this study was to assess orthopedic resident attitudes regarding mentorship and to determine if there were sociodemographic differences.

DESIGN

A total of 243 orthopedic surgery residents completed this 25-item mixed response questionnaire.

RESULTS

Nearly two-thirds of residents conveyed that their training program either had a formal or informal mentorship program, and 95.8% of residents indicated that they believed mentorship played an important role with respect to their development as an orthopedic resident. Minorities were more likely to have a mentor that was obtained while they were in medical school, less likely to have multiple mentors, and more likely to be dissatisfied with the quality of mentorship in residency. Females were more likely to pursue a mentor on their own. Overall, 31% of orthopedic residents were classified as experiencing burnout. There was no difference in the prevalence of mentorship in respondents experiencing burnout, but they were more likely to be unsatisfied with the quality of mentorship in residency. Finally, only two-thirds of residency programs have mentorship programs despite the fact that the vast majority of orthopedic residents believe that the mentorship plays an important role in their development as surgeons.

RESULTS

Given these findings, future work should focus on identifying and addressing race and sex-based mentorship disparities while simultaneously working to improve access to mentorship for all residents.

Dual-Agent Antibiotic Prophylaxis Using a Single Preoperative Vancomycin Dose Effectively Reduces Prosthetic Joint Infection Rates With Minimal Renal Toxicity Risk

BACKGROUND

We performed this study to compare prosthetic joint infection (PJI) and renal toxicity rates following hip and knee total joint arthroplasty (TJA) when a first-generation cephalosporin was administered either alone or in combination with a single preoperative vancomycin dose, whether vancomycin administration timing potentially influenced dual-antibiotic PJI prophylaxis approach effectiveness, and whether single-dose vancomycin use increased risk of renal impairment.

METHODS

This was a retrospective study of 1997 consecutive primary TJAs (1871 patients) treated with cefazolin alone (1044 TJAs) or cefazolin with single-dose vancomycin (953 TJAs). The vancomycin group included 476 TJAs (450 patients) with infusion started at least 45 minutes before the skin incision and 477 TJAs (464 patients) with infusion started less than 45 minutes before the skin incision.

RESULTS

The addition of a single dose of vancomycin did not significantly reduce PJI rates when compared with cefazolin alone (1.6% vs 2.1%, P = .32). However, the PJI rate was significantly lower following primary TJA when vancomycin administration was initiated at least 45 minutes before incision (0.2%) when compared with other TJA procedures performed using cefazolin and vancomycin (2.9%, P < .01) or cefazolin alone (2.1%, P < .01). We observed no difference in renal toxicity between treatment groups.

CONCLUSION

In our institution, the addition of vancomycin to cefazolin at least 45 minutes before incision reduced PJI infection rates in primary hip and knee TJA with a low risk of renal impairment.

Rapid destructive osteoarthritis of the hip after intra-articular steroid injection

Rapid destructive osteoarthritis of the hip is a separate entity different from the usual osteoarthritis. It is usually seen in elderly women, and the characteristic feature is the rapid progression within 6 to 12 months to complete destruction of the joint. The exact etiology is not known. We present a rare case of rapid destructive osteoarthritis of the hip in a 62-year-old woman who developed it within 2 months of intra-articular steroid injection, which was managed well with uncemented total hip arthroplasty. Through this report, we emphasize the possibility of the disastrous complication of injection, which should be informed to the patient before any intra-articular injection.

Innovations in Total Knee Arthroplasty: Improved Technical Precision, But Unclear Clinical Benefits

Total knee arthroplasty has been an effective treatment for advanced degenerative joint disease. Traditional knee designs and surgical approaches have resulted in consistently high performance, but some patients may remain dissatisfied after their surgery. Several surgical innovations, including accelerometer-based navigation, patient-specific instrumentation, and robotic-assisted total knee arthroplasty, have been developed to improve the accuracy and precision of total knee arthroplasty surgery, with anticipated secondary benefits of improved functional outcomes and implant survivorship. This article reviews the current status of these technologies as reported in contemporary orthopedic literature. [Orthopedics. 2016; 39(4):217-220.].

The Impact of Risk Reduction Initiatives on Readmission: THA and TKA Readmission Rates

We assessed whether sequential incorporation of initiatives to decrease postoperative surgical complications were similarly effective in reducing 30-day readmission rates following total knee arthroplasty (TKA) and total hip arthroplasty (THA). Readmission rates following TKA decreased substantially (5.6% vs. 3.0%, P<0.001), but readmissions following THA (4.0% vs. 3.4%, P=0.41) were not significantly reduced. The greatest impact of the multimodal treatment approach was a reduction of surgically related TKA complications. Advanced medical disease, facility discharge status, and Medicare or Medicaid coverage contributed to the highest risk for 30-day readmission after THA. Risk models defining expected readmission rates should account for these factors to avoid penalizing hospitals that provide higher proportional care to Centers for Medicaid and Medicare Services (CMS) beneficiaries.

Thromboembolism Prophylaxis in Hip Arthroplasty: Routine and High Risk Patients

This study's purpose was to present the use of a risk stratification protocol in which "routine" risk patients receive a mobile compression device with aspirin and "high" risk patients receive warfarin for thromboprophylaxis after hip arthroplasty. 1859 hip arthroplasty patients were prospectively enrolled (1402 routine risk--75.4%, 457 high risk--24.6%). The cumulative rate of venous thromboembolism events was 0.5% in the routine versus 0.5% in the high-risk cohort within 6weeks postoperatively (P=1.00). Patients in the routine risk cohort had a lower rate of major bleeding (0.5% versus 2.0%, P=0.006) and wound complications (0.2% versus 1.2%, P=0.01). Use of our risk stratification protocol allowed the avoidance of more aggressive anticoagulation in 75% of patients while achieving a low overall incidence of symptomatic VTE.

Metal Ion Concentrations in Young, Active Patients Following Total Hip Arthroplasty with the Use of Modern Bearing Couples

The purpose of this study was to compare whole blood metal ion levels in young, active patients undergoing primary total hip arthroplasty with the use of a cobalt-alloy (ten patients), ceramic (15 patients), or oxinium (11 patients) femoral head and highly crosslinked polyethylene acetabular liner. At 2 years postoperatively, mean cobalt concentrations were 3.0 times higher in the cobalt-alloy cohort versus the ceramic cohort, and 2.3 times higher versus the oxinium cohort (P=0.3-0.5). Titanium levels were consistently elevated at all postoperative time points versus preoperatively in all cohorts. Young, active patients following THA demonstrate elevated cobalt and titanium concentrations. Use of a ceramic or oxinium femoral head decreased the degree of cobalt elevation versus a cobalt-alloy femoral head, but did not reach statistical significance.

Return to Work and Functional Outcomes Following Primary Total Knee Arthroplasty in U.S. Military Servicemembers

This investigation sought to determine occupational outcomes after total knee arthroplasty (TKA) in a high-demand cohort. A total of 159 military servicemembers underwent 181 primary TKAs with mean follow-up of 4.1 (range, 2.0-6.6) years. Approximately 18% of servicemembers underwent medical separation from the military due to TKA-related limitations, and age <45 years (OR=2.36; 95% CI: 1.14, 4.90) was established as the significant risk factor. Twenty servicemembers (12.6%) performed postoperative combat deployments, with age <45 years (OR=3.10; 95% CI: 1.29, 7.47) or combat arms designation (OR=2.75; 95% CI: 1.13, 6.73) associated with higher rates of deployment. Nine revision TKAs (5.0%) were performed at an average of 1.9 years. Following TKA, 82% of servicemembers remained on active-duty or completed their military service.

LEVEL OF EVIDENCE

IV.

Mobile compression devices and aspirin for VTE prophylaxis following simultaneous bilateral total knee arthroplasty

Recently, Levy et al questioned the effectiveness of mobile compression devices (MCDs) as the sole method of thromboprophylaxis following simultaneous bilateral total knee arthroplasty (TKA). This study's purpose was to assess if the addition of aspirin to MCDs improves venous thromboembolism (VTE) prevention following simultaneous bilateral TKA. Ninety-six patients (192 TKAs) were retrospectively reviewed: 47 patients received MCDs for 10 days and aspirin for 6 weeks postoperatively based on a risk stratification protocol, while 49 patients received warfarin for 4 weeks postoperatively. One symptomatic VTE was noted in the warfarin cohort, while one patient in the MCD/aspirin cohort and three patients in the warfarin cohort were readmitted within 3 months of surgery. In appropriately selected patients, MCDs with aspirin shows promise in VTE prevention following simultaneous bilateral TKA.

Are younger patients undergoing THA appropriately characterized as active?

BACKGROUND

Surgeons perform THA to address a variety of conditions in younger patients, including osteoarthritis (OA), osteonecrosis, inflammatory arthritis, and congenital deformities. Younger patients aged 50 years or younger have been characterized as active in the literature, but a direct relationship between age and activity level has not been well substantiated. Younger patients with OA may engage in higher activity levels; however, associated medical conditions in patients with other surgical indications may not support a generalization that age is a surrogate for activity level. We recently evaluated these issues in younger patients undergoing total knee arthroplasty (TKA) and noted that the majority would not be considered active. Given this observation, we considered whether younger patients undergoing THA are characterized by high activity levels, which is relevant to understanding the long-term risk of wear-related failures.

QUESTIONS/PURPOSES

(1) Do demographic features of younger patients undergoing THA support high activity expectations? (2) Do preoperative or postoperative functional activity measures support projections that younger patients are active after THA?

METHODS

We retrospectively compared demographic characteristics and functional activity profiles (as determined by preoperative and postoperative UCLA activity scores, Harris hip scores [HHS], and SF-12 and WOMAC physical function subscores) of 704 patients who had undergone THA and were aged younger than 50 years (822 hips) with those of 484 patients (516 hips) aged between 65 and 75 years, who had undergone THA, with a minimum followup at 1 year after surgery (range, 12-160 months).

RESULTS

Compared with patients aged 65 to 75 years, younger patients undergoing THA were more often men (51%, 95% confidence interval [CI], 48.8%-53.2% versus 40%, 95% CI, 37.1%-42.9% women; p < 0.01) or had undergone surgery for osteonecrosis (29% versus 4%; 95% CI, 2.8%-5.2%; p < 0.001). Postoperative HHS, SF-12, and WOMAC scores were not appreciably different between the two patient groups. Compared with older patients, younger patients with OA had higher preoperative (5.0 ± 2.5 versus 3.9 ± 2.0, p < 0.001) and postoperative UCLA activity scores (6.8 ± 2.1 versus 5.3 ± 1.9, p < 0.001). Younger patients with diagnoses other than OA had slightly higher mean postoperative UCLA activity scores than older patients (6.0 ± 2.3 versus 5.3 ± 1.9; p < 0.001). Two hundred fifty-nine of 704 younger patients undergoing THA (37%; 95% CI, 34.9%-39.1%) returned to impact activity compared with 75 of 484 older patients undergoing THA (15.5%; 95% CI, 13.3%-17.7%) (p < 0.001).

CONCLUSIONS

Younger patients with OA are likely to return to high levels of activity after surgery, which may impact long-term wear-related implant survivorship. High activity levels are less common among younger patients with diagnoses other than OA. Age is not the ideal surrogate for activity level in patients considering THA; instead, specific activity-level measures should be used when discussing patient expectations pertaining to postoperative activity levels after arthroplasty.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

The use of warfarin for DVT prophylaxis following hip and knee arthroplasty: how often are patients within their target INR range?

The purpose of this study was to determine the percentage of time that patients are therapeutic when prescribed warfarin for chemical thromboprophylaxis following a hip or knee arthroplasty procedure. One hundred eighty-four patients receiving warfarin for 4weeks postoperatively, dosed using a Web-application accounting for patient demographics, INR levels, and concomitant medication use, were included. Patients with a target INR range between 1.7 and 2.7 were therapeutic for only 54.4% of the time (32.5% subtherapeutic, 13.0% supratherapeutic) while patients with a target INR range between 2.0 and 3.0 were therapeutic for only 45.9% of the time (39.2% subtherapeutic, 14.8% supratherapeutic). Patients receiving warfarin for chemical thromboprophylaxis are within their targeted INR range for only a limited period of time during their postoperative course.

Relationship of the posterior femoral axis of the "kinematically aligned" total knee arthroplasty to the posterior condylar, transepicondylar, and anteroposterior femoral axes

BACKGROUND

A recent proposed modification in surgical technique in total knee arthroplasty (TKA) has been the introduction of the "kinematically aligned" TKA, in which the angle and level of the posterior joint line of the femoral component and joint line of the tibial component are aligned to those of the "normal," pre-arthritic knee. The purpose of this study was to establish the relationship of the posterior femoral axis of the "kinematically aligned" total knee arthroplasty (TKA) to the traditional axes used to set femoral component rotation.

METHODS

One hundred and fourteen consecutive, unselected patients with preoperative MRI images undergoing TKA were retrospectively reviewed. The transepicondylar axis (TEA), posterior condylar axis (PCA), antero-posterior axis (APA) of the trochlear groove, and posterior femoral axis of the kinematically aligned TKA (KAA) were templated on axial MRI images by two independent observers. The relationships between the KAA, TEA, APA, and PCA were determined, with a negative value indicating relative internal rotation of the axis.

RESULTS

On average, the KAA was 0.5° externally rotated relative to the PCA (minimum of -3.6°, maximum of 5.8°), -4.0° internally rotated relative to the TEA (minimum of -10.5°, maximum of 2.3°), and -96.4° internally rotated relative to the APA (minimum of -104.5°, maximum of -88.5°). Each of these relationships exhibited a wide range of potential values.

CONCLUSIONS

Using a kinematically aligned surgical technique internally rotates the posterior femoral axis relative to the transepicondylar axis, which significantly differs from current alignment instrument targets.

Clinical outcomes following re-admission for non-infectious wound complications after primary total knee replacement

Haematomas, drainage, and other non-infectious wound complications following total knee replacement (TKR) have been associated with long-term sequelae, in particular, deep infection. However, the impact of these wound complications on clinical outcome is unknown. This study compares results in 15 patients re-admitted for wound complications within 90 days of TKR to 30 matched patients who underwent uncomplicated total knee replacements. Patients with wound complications had a mean age of 66 years (49 to 83) and mean body mass index (BMI) of 37 (21 to 54), both similar to that of patients without complications (mean age 65 years and mean BMI 35). Those with complications had lower mean Knee Society function scores (46 (0 to 100 vs. 66 (20 to 100), p = 0.047) and a higher incidence of mild or greater pain (73% vs. 33%, p = 0.01) after two years compared with the non re-admitted group. Expectations in patients with wound complications following TKR should be tempered, even in those who do not develop an infection.

Are younger patients undergoing TKAs appropriately characterized as active?

BACKGROUND

The use of TKAs in young patients is increasing. Demographic characteristics and activity levels among this patient group may affect implant selection, performance, and survivorship. Patient age (≤ 55 years) and preoperative diagnosis have been used to define this patient group, with the presumption that these patients are more active than older patients with similar indications for TKA.

QUESTIONS/PURPOSES

We questioned whether (1) demographic features of young patients support high activity expectations after TKA, and (2) preoperative or postoperative functional activity measures support projections that young patients are active after TKA.

METHODS

We retrospectively compared demographic characteristics (gender, BMI, diagnosis) and functional activity profile (as determined by preoperative and postoperative UCLA activity score and functional subscores of The Knee Society and WOMAC instruments) for 150 patients 55 years old or younger (181 TKAs) and 262 patients who were between 65 to 75 years old (314 TKAs) at the time of surgery.

RESULTS

Younger patients having TKAs were significantly more likely than older patients to be female (74% versus 60%, p < 0.001) and to have diagnoses other than osteoarthritis (18% versus 3%, p < 0.001). BMI was significantly greater among younger female patients than among other age and gender combinations (35 kg/m(2) versus 31 kg/m(2), p < 0.001). Male patients had higher mean postoperative UCLA activity scores (5.5 versus 4.4, p < 0.001), Knee Society function subscores (80.2 versus 66.4, p < 0.001), and WOMAC function subscores (82.8 versus 74.2, p < 0.01) compared with female patients, but these were not different in older versus younger patients.

CONCLUSIONS

Sustained high activity levels are not likely to be a principal cause of revision TKAs among younger patients when considering age and diagnosis alone. Determining the effect of activity on survivorship of prosthetic designs and techniques should be based on measured functional activity instead of using age and diagnosis as surrogates for activity.

LEVEL OF EVIDENCE

Level III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Has total hip arthroplasty in patients 30 years or younger improved? A systematic review

BACKGROUND

The evolution of total hip arthroplasty (THA) generally has led to improved clinical results. However, THA in very young patients historically has been associated with lower survivorship, and it is unclear whether this, or results pertaining to pain and function, has improved with contemporary THA.

QUESTIONS/PURPOSES

We performed a systematic review of the English literature on THA in patients 30 years of age and younger to assess changes in (1) indications; (2) implant selection; (3) clinical and radiographic outcomes; and (4) survivorship when comparing contemporary and historical reports.

METHODS

Multiple databases were searched for articles published between 1965 and 2011 that reported clinical and radiographic outcomes of THA in patients 30 years and younger. Sixteen retrospective case series were identified. Surgical indications, implant selection, clinical and radiographic outcomes, and survivorship of patients undergoing THAs before 1988 were compared with those performed in 1988 and after.

RESULTS

Reported THAs performed more recently were less likely to be performed for juvenile rheumatoid arthritis than earlier procedures. Cementless fixation became more prevalent in later years. Although clinical outcome scores remained constant, aseptic loosening and revision rates decreased substantially with more contemporary procedures.

CONCLUSIONS

This review of the literature demonstrates an improvement in radiographic outcomes and survivorship of THA, but no significant differences in pain and function scores, in very young patients treated over the past two decades when compared with historical controls.

Periprosthetic total knee arthroplasty fractures: revision arthroplasty technique

With increased use of total knee arthroplasty (TKA) technique, the burden of revision surgery for all causes including periprosthetic fractures is anticipated to increase substantially in the coming decades. Although periprosthetic TKA fractures are most frequently managed with operative repair, there are circumstances where fracture characteristics or patient factors may make a revision total knee arthroplasty more preferable. This article outlines the principles of surgical treatment when a revision arthroplasty technique is selected.

Is routine mid-term total hip arthroplasty surveillance beneficial?

BACKGROUND

Routine followup of patients after primary or revision THA is commonly practiced and driven by concerns that delays in identifying early failure will result in more complicated or more costly surgical interventions. Although mid-term followup (4-10 years) has been performed to follow cohorts of patients, the benefit of observing individual patients regardless of symptoms has not been established.

QUESTIONS/PURPOSES

We determined (1) the reasons patients with THA return for mid-term followup, (2) the treatment recommendations and interventions occurring as a result of mid-term followup, and (3) how frequently revision surgery is recommended for asymptomatic and symptomatic patients at mid-term followup.

METHODS

We retrospectively identified 501 patients (503 hips) who returned for followup at least 4 years (mean, 5 years; range, 4-10.9 years) after their primary or revision THA. We recorded their reasons for followup and treatment recommendations, including those for revision surgery, at mid-term followup.

RESULTS

Fifty-three percent of patients returning for routine followup had no symptoms, 31% reported an unrelated musculoskeletal concern, and 19% had symptoms from their primary THA (15%) or revision THA (32%). Sixty-nine percent of symptomatic patients and 10% of asymptomatic patients received treatment recommendations, with physical therapy as the most frequent intervention (74%). Revision surgery was recommended for 6% of symptomatic and 0.6% of asymptomatic patients.

CONCLUSIONS

Although routine surveillance may identify rare, asymptomatic patients with arthroplasty failure, it is much more likely to result in recommendations for nonoperative management during early followup.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Assessing readmission databases: how reliable is the information?

Databases are being used to shape health care policy. However, the reliability of coding information entered into the databases may be difficult to validate. In this study, we assess readmission data from an institutional database that identified 1515 readmissions (708 patients) after total hip or total knee arthroplasty during a 5-year interval. After exclusions, 223 readmissions (190 patients) underwent medical record review. Bleeding, wound-related, and arthroplasty-related complications constituted most (62.8%) of readmissions. Bleeding and wound complications were nearly 6 times more frequently associated with readmission than venous thromboembolism events. On secondary review, there was discordance between the diagnosis obtained by a surgeon reviewer and coding for diagnoses consistent with periprosthetic infection (996.66, 77, 78, and 998.59) in 70% of cases. The findings of our study raise questions regarding the validity of accepting information obtained from larger databases without closer scrutiny.

The reliability and variation of acetabular component anteversion measurements from cross-table lateral radiographs

Although cross-table lateral (CL) radiographs are frequently used to assess acetabular component anteversion, the reliability of this method has not been established. We compared serial CL radiographs with computed tomography (CT) scans for 98 total hip arthroplasty patients (119 hips) undergoing surveillance of primary or revision total hip arthroplasty. Acetabular anteversion averaged 26.1° (range, -2° to 48.3°) on CL imaging and 28.8° (range, -7° to 54°) on CT scan. There was a strong correlation between anteversion determined from CT scans and serial CL images. However, variation on serial CL studies exceeded 10° for 20% of patients. Although CL imaging provides acceptable assessment of general component position, it has limited use for precise analysis in research, outcome reporting, or determination of cause of implant failure.

What is the evidence for total knee arthroplasty in young patients?: a systematic review of the literature

BACKGROUND

TKA is commonly performed to treat advanced inflammatory and degenerative knee arthritis. With increasing use in younger patients, it is important to define the best practices to enhance clinical performance and implant longevity.

QUESTIONS/PURPOSES

We systematically reviewed the literature to assess: (1) how TKAs perform in young patients; (2) whether the TKA is a durable procedure for young patients, and (3) what guidance the literature outlines for TKA in young patients.

METHODS

We searched the literature between 1950 and 2009 for all studies reporting on TKAs for patients younger than 55 years that documented clinical and radiographic assessments with a minimum 2-year followup. Thirteen studies, reporting on 908 TKAs performed for 671 patients, met these criteria.

RESULTS

Mean Knee Society clinical and functional scores increased by 47 and 37 points, respectively. Implant survivorship was reported between 90.6% and 99% during the first decade and between 85% and 96.5% during the second decade of followup. The literature does not direct specific techniques for TKA for young patients.

CONCLUSIONS

TKA provides surgeon-measured clinical and functional improvements with a moderate increase in second-decade implant failures. Improvements in study design and reporting will be beneficial to guide decisions regarding implant selection and surgical technique.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Large acetabular defects can be managed with cementless revision components

BACKGROUND

Optimal techniques for acetabular revision in the setting of major pelvic osteolysis have not been established. Bilobed components, structural grafts, and reinforcement cages have demonstrated 10-24% midterm failure rates. While cementless hemispherical components have been utilized to treat large acetabular defects, most reports have not focused specifically on patients with extensive deficiencies.

QUESTIONS/PURPOSES

We report midterm clinical scores, component revisions, and complications following focal bone grafting and cementless acetabular revision in cases with major periacetabular osteolysis.

METHODS

We identified 30 patients (32 hips) who underwent cementless acetabular revision to treat massive acetabular bone loss at an average followup of 53 months. We excluded three patients lost to followup and two patients who died prior to minimum 24 month followup. Harris Hip Scores were assessed before and after surgery. Postoperative radiographs were evaluated for graft incorporation and component migration. Component revision and component migration are reported as failures.

RESULTS

Mean Harris Hip Score improved from 52.5 (range, 17.7-90.7) to 87.3 (range, 25.3-100) points. Three hips (9%) were revised for aseptic loosening. Three components (10.7%) demonstrated radiographic migration, but were not revised. Complete graft incorporation was seen in 17 cases (68%). There were five major complications (14%).

CONCLUSIONS

Cementless acetabular fixation and bone grafting result in clinical scores and survivorship comparable to other options at midterm followup, with potential for biological fixation.

LEVEL OF EVIDENCE

Level IV, clinical research study. See the Guidelines for Authors for a complete description of levels of evidence.

Outcomes of internal fixation in a combat environment

Due to the nature of the wounds and environment, internal fixation in battlefield treatment facilities is discouraged despite the lack of data. The purpose of this review is to describe the outcomes of fractures that were internally fixed in the combat environment. The records of patients who had internal fixation performed in the theater of combat operations were reviewed. Demographics, injury characteristics, procedure history, and outcomes were recorded and analyzed. Forty-seven patients had internal fixation performed on 50 fractures in a combat theater hospital. Hip, forearm, and ankle fractures made up the majority of cases with 14 (28%), 14 (28%), and 10 (20%), respectively. Sixteen (32%) fractures were open. The average Injury Severity Score was 11.4 +/- 1.1 (range, 4-34). Thirty-nine fractures (78%) healed without incidence. There was one (2%) infection and one (2%) acute surgical complication. Ten (20%) fractures, including the one infection, required additional procedures. Because internal fixation in the combat environment was used judiciously, complications were not higher than previously reported.