Total hip arthroplasty (THA) is a tried-and-true treatment for debilitating hip osteoarthritis. But as the number of patients undergoing THA continues to rise, so does the incidence of periprosthetic femoral fractures and the need for revision surgery. The increasing burden of periprosthetic fractures has led to the development of shorter-stemmed femoral components that theoretically preserve bone, decrease fracture risk, and make revision surgery easier if it is required. In the January 6, 2021 issue of The Journal, Slullitel et al. report on a randomized controlled trial that determined whether bone loss differed between patients who received a conventional stem and those who received a short, bone-preserving stem over 2 years following THA.
Forty-six patients received the short, proximally porous-coated stem (Depuy Synthes Tri-Lock bone-preservation stem), and 40 received the conventional stem (Depuy Synthes collarless Corail stem). The primary outcome–bone mineral density (BMD)–was analyzed at 12, 26, 52, and 104 weeks after surgery with dual x-ray absorptiometry region-free analysis (DXA-RFA), which revealed pixel-level resolution of BMD at the bone-implant interface.
Immediately after surgery, researchers found a similar amount of bone loss in both groups in the calcar region and the cancellous portion of the distal greater trochanter. But at all other subsequent time points, bone loss was significantly greater in patients with the bone-preserving stem (analysis of variance [ANOVA] p < 0.0001). In addition, over the full study period the small areas of bone gain that the researchers found were statistically greater in the conventional-stem group than in the Tri-Lock group. Notably, patient-reported outcomes and adverse events did not differ between the 2 groups at the 2-year follow-up.
These early results cast a shadow of doubt over whether a stem that is marketed to preserve bone actually accomplishes that objective. However, 2 years is a very short follow-up when looking at the lifetime of a hip arthroplasty, and the clinical implications of these findings will become clearer with longer-duration analysis.
Click here to read a JBJS Clinical Summary titled “Short-Stem Femoral Components in THA” by Tad Mabry, MD.
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
There are many more “types” of diabetes than the pathophysiologic designations of Type 1 and Type 2. In the December 16, 2020 issue of The Journal of Bone & Joint Surgery, Na et al. delineate 4 different diabetes categories and determine their impact on 90-day complications and readmission rates after elective total joint arthroplasty (TJA) among Medicare patients. One premise for this investigation was that, although diabetes is a known risk factor for arthroplasty complications, alternative payment models such as the federally run Comprehensive Care for Joint Replacement (CJR) program adjust their payments only in diabetes cases where the comorbidity is coded as severe.
The authors stratified diabetes into 4 groups as follows:
- No diabetes
- Controlled-uncomplicated diabetes
- Controlled-complicated diabetes
- Uncontrolled diabetes
Among the >500,000 total knee arthroplasties (TKAs) and total hip arthroplasties (THAs) analyzed, the authors found the following when comparing data from the 3 diabetes groups with the no-diabetes group:
- The odds of TKA complications were significantly higher for those with uncontrolled diabetes (odds ratio [OR] = 1.29).
- The odds of THA complications were significantly higher for those with controlled-complicated diabetes (OR = 1.45).
- The odds of readmission were significantly higher in all diabetes groups for both TKA (ORs = 1.21 to 1.48) and THA (ORs = 1.20 to 1.70).
The authors come to 3 basic conclusions based on these findings:
- The odds of hospital readmission and complications following an elective TKA or THA are increased for Medicare beneficiaries who have diabetes.
- It would be reasonable to defer arthroplasty surgery for those with uncontrolled diabetes to allow them to achieve glycemic control.
- The Centers for Medicare & Medicaid Services should include less-severe diabetes and associated systemic complications in alternative-payment model adjustments.
Click here for an “Author Insight” video about this study from co-author Annalisa Na, PhD, DPT.
No consensus has emerged yet regarding the best prosthetic construct with which to manage patients who require revision surgery for dislocation after a total hip arthroplasty (THA). But in the December 2, 2020 issue of The Journal of Bone & Joint Surgery, Hoskins et al. add insight into that question by tapping the Australian Orthopaedic Association Total Joint Replacement Registry to analyze which of 4 first-revision component constructs led to the fewest second revisions.
Among the 1,275 THAs that were revised once for prosthesis dislocation, 203 hips went on to have a second revision, with dislocation being the most common cause for re-revision. The authors studied the second-revision THAs in 4 prosthetic categories: standard-sized femoral heads, large-sized femoral heads, dual-mobility heads, and constrained acetabular liners. The rate of all-cause second revision was significantly higher in the standard-head group when compared with the constrained-liner group. But in the 91 cases of second revisions for dislocation, the standard head showed significantly higher second-revision rates than any of the other 3 constructs. There was no statistically significant difference in rates of second revision between those 3 non-standard articulations
The authors discuss dual-mobility heads at some length, asserting that “caution should be exercised in their routine use, particularly in younger and active patients.” They note that the constrained liner was the “only articulation to show a difference when compared with standard-head THA for both all-cause revision and revision for a subsequent diagnosis of dislocation,” but they observe that impingement and acetabular component loosening are common concerns with constrained liners.
Despite these caveats, it seems clear from this data that the choice of articulating surface for either a first or second revision THA due to dislocation should probably exclude standard head sizes. Calling for longer-term data on all 3 alternative constructs studied here (the follow-up periods were different for all 4 articulations), the authors emphasize that “surgeons should [also] look beyond articulating surfaces”—to surgical approach, component orientation, and patient factors such as soft-tissue quality—in the effort to reduce the burden of THA dislocations.
Remember when a “dashboard” referred to the display just behind a car’s steering wheel? In today’s digital universe, the word has come to mean any number of visual information displays. At the same time, the meaning of the word “value” has narrowed somewhat. In relation to health care, “value” is defined quite precisely as the quality of patient outcomes per dollar spent on healthcare services.
In the November 4, 2020 issue of The Journal of Bone & Joint Surgery, Reilly et al. explain how they created a “value dashboard” for total hip and knee arthroplasty (THA and TKA) at a tertiary-care medical center in New England. The goal: track and display the surgeon-level cost and quality of these procedures against institutional benchmarks to identify opportunities for improving value.
The 7 quality metrics that Reilly et al. used included both clinical and patient-reported outcomes, weighted by surgeons using a modified Delphi process. Average direct costs per surgeon were calculated from the medical center’s billing system, and data were collected over a 15-month period from 2017 to 2018 to ensure at least 1 year of outcomes. Six surgeons were included in the TKA value dashboard, and 5 were included in the THA dashboard.
Relative to the institutional benchmarks:
- Value for TKA by surgeon ranged from 7% below benchmark to 12% above.
- Value for THA by surgeon ranged from 12% below benchmark to 7% above.
The dashboard itself (see Figure above) displays quality, cost, and overall value so viewers can see at a glance which metrics are driving the value score for each surgeon, whose procedural volume is also depicted. The authors cite as one limitation of this study the fact that the quality metrics were weighted by local surgeons only, and they say that “ideally the weighting would be informed by a panel of national experts and several stakeholder groups,… including patients.”
The cost of medical care in the United States has been shown to rise with advancing patient age, and total joint arthroplasty (TJA) is a prime example of this unsurprising phenomenon. In attempts to curtail costs and reduce variability, Medicare and other payers have introduced alternative payment models (APMs), such as the Bundled Payments for Care Improvement (BPCI) initiative. In this model’s application to TJA, when participating institutions keep the cost of the “episode” below a risk-adjusted target price, they accrue the savings as a profit, but they sustain a financial penalty if the episode costs more than the target price.
Multiple studies have suggested that APMs can negatively affect the fiscal health of institutions that care for many high-risk patients. Although increasing age has been associated with higher-cost episodes of care, age is not one of the factors that the BPCI model accounts for. Consequently, concerns have been raised that providers may practice “cost discrimination” against very old patients.
In the October 7, 2020 issue of The Journal, Petersen et al. examine how an aging population has affected a New York City orthopaedic center in terms of the BPCI model applied to TJA. The authors analyzed the relationship between patient age and cost of care among 1,662 patients who underwent primary total hip and knee arthroplasty over a 3-year period under BPCI. They then used a modeling tool to predict shifting age demographics for their local area out to the year 2040.
Petersen et al. found that under BPCI, their institution sustained a nearly $2,000-per-case loss for TJA care episodes among patients 85 to 99 years of age. Currently this loss is offset by profits realized by performing TJAs in younger patients. However, predictive modeling identified an inflection point of 2030, after which a relative increase in older patients and a decrease in younger patients will yield an overall net decrease in profits for primary TJA.
Because no one, including orthopaedic surgeons, can turn back the clock on aging, health care stakeholders must find ways either to adjust downward the cost of care for the elderly (seemingly difficult without adversely affecting outcomes) or adjust reimbursement models to account for the increased costs associated with aging. I agree with the conclusion of Petersen et al.: “The BPCI initiative and [other] novel APMs should consider age as a modifier for reimbursement to incentivize care for the more vulnerable and costly age groups in the future.”
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
Every month, JBJS reviews the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Click here for a collection of all OrthoBuzz specialty-update summaries.
This month, Mengnai Li, MD, PhD, co-author of the September 16, 2020 “What’s New in Hip Replacement,” selected the five most clinically compelling findings from among the 95 noteworthy studies summarized in the article.
Medical Comorbidities and Outcomes of Joint Arthroplasty
–Among 543 malnourished joint arthroplasty patients (with albumin levels <3.4 g/L), an intervention encouraging a high-protein, anti-inflammatory diet shortened the length of hospital stay and lowered readmissions, relative to malnourished arthroplasty patients who did not receive the intervention.1
Surgical Factors and Outcomes of Total Hip Arthroplasty (THA)
–A multicenter, prospective study used propensity-score matching to compare THA performed with a direct anterior approach with THA performed with a posterolateral approach. Researchers found no patient-reported outcome differences at 1.5 months postoperatively or at ≥1 year up to 5 years.2
Periprosthetic Joint Infection (PJI)
–A Musculoskeletal Infection Society workgroup published a recommendation for a 4-tier tool for reporting outcomes after surgical treatment of PJI. Proposed outcomes include infection control with no antibiotic treatment, infection control with suppressive antibiotic therapy, need for reoperation and/or revision and/or spacer retention, and death.
–A meta-analysis found only low-quality retrospective evidence supporting the practice of routinely applying intrawound vancomycin to reduce the rates of PJI. Authors called for a prospective randomized trial before adoption of this practice.3
Postoperative Urinary Retention
–A randomized controlled trial found that preoperative and perioperative administration of tamsulosin did not reduce the incidence of postoperative urinary retention after hip and knee arthroplasty. However, the study included a general male population rather than a higher-risk group.4
- Schroer WC, LeMarr AR, Mills K, Childress AL, Morton DJ, Reedy ME. 2019 Chitranjan S. Ranawat Award: elective joint arthroplasty outcomes improve in malnourished patients with nutritional intervention: a prospective population analysis demonstrates a modifiable risk factor. Bone Joint J.2019 Jul;101-B(7_Supple_C):17-21.
- Sauder N, Vestergaard V, Siddiqui S, Galea VP, Bragdon CR, Malchau H, Elsharkawy KA, Huddleston JI 3rd, Emerson RH. The AAHKS Clinical Research Award: no evidence for superior patient-reported outcome scores after total hip arthroplasty with the direct anterior approach at 1.5 months postoperatively, and through a 5-year follow-up. J Arthroplasty.2020 Feb 12.
- Heckmann ND, Mayfield CK, Culvern CN, Oakes DA, Lieberman JR, Della Valle CJ. Systematic review and meta-analysis of intrawound vancomycin in total hip and total knee arthroplasty: a call for a prospective randomized trial. J Arthroplasty.2019 Aug;34(8):1815-22. Epub 2019 Apr 1.
- Schubert MF, Thomas JR, Gagnier JJ, McCarthy CM, Lee JJ, Urquhart AG, Pour AE. The AAHKS Clinical Research Award: prophylactic tamsulosin does not reduce the risk of urinary retention following lower extremity arthroplasty: a double-blinded randomized controlled trial. J Arthroplasty.2019 Jul;34(7S):S17-23. Epub 2019 Mar 20.
There is a wry saying in academic medicine that “nothing ruins good results like long-term follow-up.” But long-term follow-up helps us truly understand how our orthopaedic interventions affect patients. This is especially important with procedures on children, and the orthopaedic surgeons at the University of Iowa have been masterful with long-term outcome analysis in pediatric orthopaedics. They demonstrate that again in the August 5, 2020 issue of The Journal, as Scott et al. present their results comparing outcomes among 2 cohorts of patients who underwent treatment for developmental hip dislocations between the ages of 18 months and 5 years—and who were followed for a minimum of 40 years.
Seventy-eight hips in 58 patients underwent open reduction with Salter innominate osteotomy, and 58 hips in 45 patients were treated with closed reduction. At 48 years after reduction, 29 (50%) of the hips in the closed reduction cohort had undergone total hip arthroplasty (THA), compared to 24 (31%) of hips in the open reduction + osteotomy group. This rate of progression to THA nearly doubled compared to previously reported results at 40 years of follow-up, when 29% of hips in the closed reduction group and 14% of hips in the open reduction group had been replaced.
In addition, the authors found that patient age at the time of reduction and presence of unilateral or bilateral disease affected outcomes. Patients with bilateral disease who were treated at 18 months of age had a much lower rate of progression to THA when treated with closed reduction, compared to those treated with open reduction—but the opposite was true among patients with bilateral disease treated at 36 months of age. Treatment type and age did not seem to substantially affect hip survival among those with unilateral disease.
I commend the authors for their dedication to analyzing truly long-term follow-up data to help us understand treatment outcomes among late-diagnosed developmental hip dislocations in kids. Long-term follow-up may “ruin” good results, but it gives us more accurate and useful results. And, in this case, the findings reminded us how important it is to diagnose and treat developmental hip dislocations as early in a child’s life as possible.
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
Acetabular components for primary total hip arthroplasty (THA) made with ultraporous surfaces were developed to enhance osseointegration and biological fixation. In the July 1, 2020 issue of The Journal of Bone & Joint Surgery, Palomaki et al. report on a registry study that suggests that implant survival with these components over an average follow-up of 3.6 years is not so “ultra.”
The authors evaluated >6,000 primary THAs that used a Tritanium ultraporous cup and >25,000 THAs that used a conventional cup, all performed between 2009 and 2017. When they compared the two groups for revision for any reason, the 5-year Kaplan-Meier survivorship of the Tritanium group (94.7%) was inferior to that of the conventional-cup group (96.0%). When revision for aseptic loosening was examined, the 5-year survivorship was also inferior for the Tritanium group (99.0%) compared with the conventional group (99.9%). Regression analysis revealed that the Tritanium group had a much higher risk of revision for aseptic loosening 2 to 4 years after surgery (hazard ratio, 11.2; p <0.001). Interestingly, these survivorship and risk-of-revision differences disappeared when the authors analyzed data for the period from May 15, 2014 to December 31, 2017–when the registry was updated to include patient BMI and ASA-class data.
The authors cite several caveats that readers should apply to these findings. The registry did not capture radiographic findings for these patients, so potentially relevant imaging data could not be analyzed. And, despite the database upgrade in 2014, there was a dearth of available data on patient comorbidities. Finally, wide confidence intervals for some of the hazard-ratio calculations suggest the need to confirm revision-risk findings with further research.
Limitations notwithstanding, the study by Palomaki et al. suggests that the performance of ultraporous cups may not meet the hopes and expectations of hip surgeons and their patients.
OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Eric Secrist, MD in response to a recent study in Arthritis Research & Therapy.
There has been a proliferation of research regarding postoperative opioid usage after joint arthroplasty due to the widespread opioid epidemic. But Rajamäki and colleagues from Tampere University in Finland took the unique approach of also analyzing acetaminophen and NSAID usage in addition to opioids. The authors used robust data from Finland’s nationwide Drug Prescription Register, which contains reliable information on all medications dispensed from pharmacies, including over-the-counter drugs.
After excluding patients who underwent revision surgery or had their knee or hip replaced for a diagnosis other than osteoarthritis, the authors analyzed 6,238 hip replacements in 5,657 patients and 7,501 knee replacements in 6,791 patients, all performed between 2002 and 2013. The mean patient age was 68.7 years and the mean BMI was 29.
One year postoperatively, 26.1% of patients were still filling prescriptions for one or more analgesics, including NSAIDs (15.5%), acetaminophen (10.1%), and opioids (6.7%). Obesity and preoperative analgesic use were the strongest predictors of prolonged analgesic medication usage 1 year following total joint arthroplasty. Other predictors of ongoing analgesic usage included older age, female gender, and higher number of comorbidities. Patients who underwent knee replacement used the 3 analgesics more often than those who underwent hip replacement.
This study had all of the limitations inherent in retrospective database analyses. Additionally, it was not possible for the authors to determine whether patients took analgesic medications for postoperative knee or hip pain or for pain elsewhere in their body. Finally, the authors utilized antidepressant reimbursement data as a surrogate marker for depression and other medications as a surrogate for a Charlson Comorbidity Index.
Figure 2 from this study (shown below) reveals 2 important findings. First, total joint arthroplasty resulted in a significant decrease in the proportion of patients taking an analgesic medication, regardless of BMI. Second, patients in lower BMI categories were less likely to use analgesics both preoperatively and postoperatively.
The findings from this study may be most useful during preoperative counseling for obese patients, who often present with severe joint pain but are frequently told they need to delay surgery to lose weight and improve their complication-risk profile. Based on this study, those patients can be counseled that losing weight will not only decrease their complication risk, but also decrease their reliance on medications for the pain that led them to seek surgery in the first place.
Eric Secrist, MD is a fourth-year orthopaedic resident at Atrium Health in Charlotte, North Carolina.
This post comes from Fred Nelson, MD, an orthopaedic surgeon in the Department of Orthopedics at Henry Ford Hospital and a clinical associate professor at Wayne State Medical School. Some of Dr. Nelson’s tips go out weekly to more than 3,000 members of the Orthopaedic Research Society (ORS), and all are distributed to more than 30 orthopaedic residency programs. Those not sent to the ORS are periodically reposted in OrthoBuzz with the permission of Dr. Nelson.
Up to 33% of patients are dissatisfied with their outcome after a knee or hip replacement. It’s evident that successful recovery from lower-limb joint replacement is aided by leg strength and stamina, but handgrip strength has been proposed as a proxy for a person’s overall muscle strength. A recent prospective cohort study1 of 226 patients who underwent total hip arthroplasty (THA) and 246 patients who underwent total knee arthroplasty (TKA) investigated the association between handgrip strength measured preoperatively with a dynamometer and changes in preoperative versus 1-year postoperative patient-reported outcome scores. Researchers analyzed the data after adjusting for sex, body mass index, and baseline scores.
For both THA and TKA patients, handgrip strength was positively associated with most physical function, symptom, and quality-of-life scores measured with HOOS, KOOS, and SF-36 questionnaires. On the other hand, there was no association between grip strength and mental-component scores in either the THA or TKA group.
Based on a review of the literature and this study’s findings, the authors conclude that the association between handgrip strength and THA/TKA outcomes is partly dependent on the joint site. Although the mechanism to explain the association has not been elucidated, translating these findings into an informal dynamometer-based tool could help clinicians counsel prospective joint-replacement patients about the value of preoperative conditioning.
1. Meessen JMTA, Fiocco M, Tordoir RL, Sjer A, Verdegaal SHM, Slagboom PE, Vliet Vlieland TPM, Nelissen RGHH. Association of handgrip strength with patient-reported outcome measures after total hip and knee arthroplasty. Rheumatol Int. 2020 Apr;40(4):565-571. doi: 10.1007/s00296-020-04532-5. Epub 2020 Feb 18. PMID: 32072233