An estimated 7 million people living in the US have undergone a total joint arthroplasty (TJA), and the demand for total hip arthroplasty (THA) and total knee arthroplasty (TKA) will almost certainly increase during the next 15 years. But how many people can expect to have an additional TJA after having a first one?
That’s the question Sanders et al. address in their historical cohort study, published in the March 1, 2017 edition of The Journal of Bone & Joint Surgery. They followed more than 4,000 patients who underwent either THA or TKA between 1969 and 2008 to assess the likelihood of those patients undergoing a subsequent, non-revision TJA.
Here’s what they found:
- Twenty years after an initial THA, the likelihood of a contralateral hip replacement was 29%.
- Ten years after an initial THA, the likelihood of a contralateral knee replacement was 6%, and the likelihood of an ipsilateral knee replacement was 2% at 20 years.
- Twenty years after an initial TKA, the likelihood of a contralateral knee replacement was 45%.
- After an initial TKA, the likelihood of a contralateral hip replacement was 3% at 20 years, and the likelihood of an ipsilateral hip replacement was 2% at 20 years.
In those undergoing an initial THA, younger age was a significant predictor of contralateral hip replacement, and in those undergoing an initial TKA, older age was a predictor of ipsilateral or contralateral hip replacement.
The authors conclude that “patients undergoing [THA] or [TKA] can be informed of a 30% to 45% chance of a surgical procedure in a contralateral cognate joint and about a 5% chance of a surgical procedure in noncognate joints within 20 years of initial arthroplasty.” They caution, however, that these findings may not be generalizable to populations with more racial or socioeconomic diversity than the predominantly Caucasian population they studied.
Every month, JBJS publishes a Specialty Update—a review of 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, Gwo-Chin Lee, MD, author of the January 18, 2017 Specialty Update on Adult Reconstructive Knee Surgery, selected the five most clinically compelling findings from among the more than 100 studies summarized in the Specialty Update.
Nonoperative Knee OA Treatment
—Weight loss is one popular nonoperative recommendation for treating symptoms of knee osteoarthritis (OA). An analysis of data from the Osteoarthritis Initiative found that delayed progression of cartilage degeneration, as revealed on MRI and clinical symptoms, positively correlated with BMI reductions >10% over 48 months.1
Total Knee Arthroplasty
—In total knee arthroplasty (TKA), the drive toward producing normal anatomy has led to explorations of alternative alignment paradigms. A prospective randomized study found that small deviations from the traditional mechanical axis (known as kinematic alignment) can be well tolerated and do not lead to decreased survivorship or poorer functional outcomes at short-term follow up.2
—Controversy exists about the optimal method to achieve stemmed implant fixation in revision TKA. A randomized controlled trial of TKA patients with mild to moderate tibial bone loss found no difference in tibial implant micromotion between cemented and hybrid press-fit stem designs, based on radiostereometric analysis.
Blood Management in TKA
—Minimizing blood loss and transfusions is crucial to minimizing complications after TKA. A randomized, double-blind, placebo-controlled trial found that intra-articular and intravenous administration of tranexamic acid (TXA) was more effective than intravenous TXA alone, without an increased risk of venous thromboembolism (VTE). However, the optimal regimen for TXA remains undefined.
—VTE prophylaxis is essential for all patients undergoing TKA. A risk-stratification study of pulmonary embolism (PE) after elective total joint arthroplasty reported that the incidence of PE within 30 days after either hip or knee replacement was 0.5%. Risk factors associated with PE were age of > 70 years, female sex, and higher BMI. The presence of anemia was protective against PE. The authors developed an easy-to-use scoring system to determine risk for VTE to help guide chemical prophylaxis.3
- Gersing AS, Solka M, Joseph GB, Schwaiger BJ, Heilmeier U, Feuerriegel G, Nevitt MC, McCulloch CE,Link TM. Progression of cartilage degeneration and clinical symptoms in obese and overweight individuals is dependent on the amount of weight loss: 48-month data from the Osteoarthritis Initiative. Osteoarthritis Cartilage. 2016 Jul;24(7):1126-34. Epub 2016 Jan 30.
- Calliess T, Bauer K, Stukenborg-Colsman C, Windhagen H, Budde S, Ettinger M. PSI kinematic versus non-PSI mechanical alignment in total knee arthroplasty: a prospective, randomized study. Knee Surg Sports Traumatol Arthrosc. 2016 Apr 27. [Epub ahead of print]
- Bohl DD, Maltenfort MG, Huang R, Parvizi J, Lieberman JR, Della Valle CJ. Development and validation of a risk stratification system for pulmonary embolism after elective primary total joint arthroplasty. J Arthroplasty. 2016 Sep;31(9)(Suppl):187-91. Epub 2016 Mar 17.
OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Richard Yoon, MD and Grigory Gershkovich, MD.
The AAOS recently reviewed the evidence for surgical management of osteoarthritis of the knee (SMOAK) and issued a set of appropriate use criteria (AUC) that help determine the appropriateness of clinical practice guidelines (CPGs). These AUC can be accessed on the OrthoGuidelines website: www.orthoguidelines.org/auc.
The AUC were developed after a panel of specialists reviewed the 2015 CPGs on SMOAK and made appropriateness assessments for a multitude of clinical scenarios and treatments. The panel found 21% of the voted-on items “appropriate”; 25% were designated “maybe appropriate,” and 54% were ranked as “rarely appropriate.”
Importantly, these AUC do not provide a substitute for surgical decision making. The physician should always determine treatment on an individual basis, ideally with the patient fully engaged in the decision.
This OrthoBuzz post summarizes some of the updated conclusions according to three clinical time points—pre-operative, peri-operative, and postoperative—specifying the strength of supporting evidence. This post is not intended to review appropriateness for every clinical scenario. We encourage physicians to explore the OrthoGuidelines website for complete AUC information.
Strong evidence: Obese patients exhibit minimal improvement after total knee arthroplasty
(TKA), and such patients should be counseled accordingly.
Moderate evidence: Diabetic patients have a higher risk of complications after TKA.
Moderate evidence: An 8-month delay to TKA does not worsen outcomes.
Strong evidence: Both peri-articular local anesthetics and peripheral nerve blocks decrease postoperative pain and opioid requirements.
Moderate evidence: Neuraxial anesthesia may decrease complication rates and improve select peri-operative outcomes.
Moderate evidence: Judicious use of tourniquets decreases blood loss, but tourniquets may also increase short-term post-operative pain.
Strong evidence: The use of tranexamic acid (TXA) reduces post-operative blood loss and the need for transfusions.
Strong evidence: Drains do not help reduce complications or improve outcomes.
Strong evidence: There is no difference in outcomes between cruciate-retaining and posterior stabilized implants.
Strong evidence: All-polyethylene and modular components yield similar outcomes.
Strong, moderate, and limited evidence to support either cemented or cementless techniques, as similar outcomes and complication rates were found.
Strong evidence: There is no difference in pain/function with patellar resurfacing.
Moderate evidence: Patellar resurfacing decreases 5-year re-operation rates.
Moderate evidence shows no difference between unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO).
Moderate evidence favors TKA over UKA to avoid future revisions.
Strong evidence against the use of intraoperative navigation and patient-specific instrumentation, as no difference in outcomes has been observed.
Strong evidence: Rehab/PT started on day of surgery reduces length of stay.
Moderate evidence: Rehab/PT started on day of surgery reduces pain and improves function.
Strong evidence: The use of continuous passive motion machines does not improve outcomes after TKA.
Richard Yoon, MD is a fellow in orthopaedic traumatology and complex adult reconstruction at Orlando Regional Medical Center.
Grigory Gershkovich, MD is chief resident at Albert Einstein Medical Center in Philadelphia. He will be completing a hand fellowship at the University of Chicago in 2017-2018.
Of the hundreds of thousands of total knee arthroplasties (TKAs) performed annually around the world, very few result in failure so irreparable that transfemoral amputation is the last resort. But what does “very few” really mean? In the December 7, 2016 issue of The Journal of Bone & Joint Surgery, Gottfriedsen et al. determine the cumulative incidence of amputation for failed TKAs among nearly 93,000 registered knee replacements performed in Denmark from 1997 to 2013.
The authors used a competing-risk model (which took into account the competing risk of death) to avoid overestimating incidence. From a total of 115 amputations performed for causes related to failed TKA, they calculated a cumulative 15-year incidence of amputation of 0.32%. They noted a tendency toward decreasing incidence during the 2008-2013 period, relative to the 1997-2002 period.
The three most common causes of post-TKA amputation were periprosthetic infection (83%), soft-tissue deficiency (23%), and severe bone loss (18%). The authors add, however, that the latter two causes are “most likely the result of long-term infection together with several revision procedures, in which soft tissue and bone stock are gradually damaged.”
The authors encourage orthopaedists to consider newer treatment options to avoid amputation (such as skin grafts and muscle flaps for soft-tissue loss), but they also assert that, in each individual case, those contemporary approaches should be balanced against the “psychological and physical strains related to repeated surgery performed in an attempt to salvage the knee.”
Hyaluronic Acid Injections for Treatment of Advanced Osteoarthritis of the Knee: Utilization and Cost in a National Population Sample
There is a rise in knee osteoarthritis, particularly in the aging U.S. population. A practice known as hyaluronic acid (HA) injections is used for the treatment of knee osteoarthritis; however, its efficacy and cost-effectiveness are being debated. In this study, the utilization and costs of HA injections were evaluated during the 12 months preceding total knee arthroplasty (TKA) and the usage of HA injections in end-stage knee osteoarthitis management in relation to other treatments was also evaluated. Truven Health Analytics databases (MarketScan Commercial Claims and Encounters and Medicare Supplemental and Cooridination of Benefits) were reviewed in order to find patients who underwent TKA from 2005 to 2012. All patient-specific osteoarthritis-related health care, including medications, corticosteroid injections, HA injections, imaging, and office visits, as well as payment information were analyzed during the 12 months before TKA.
244,059 patients met the inclusion criteria, and 35,935 (14.7%) of them had > 1 HA injections in the 12-month period. HA accounted for 16.4% of all payments related to osteoarthritis, coming in second only to imaging studies (18.2%). In terms of treatment-specific payments, HA injections accounted for 25.2%, a rate higher than that of any other treatment. Compared with patients who did not receive HA injections, patients who had the injections were significantly more likely to receive additional knee osteoarthritis-related treatment.
HA injections are still frequently used to treat osteoarthritis of the knee even though there have been numerous studies that question their efficacy and cost-effectiveness for that purpose. Based on the results and a lack of data supporting the effectiveness of HA injections in the current cost-conscious health-care climate, the authors of this study concluded that decreasing the use of HA injections for patients with end-stage knee osteoarthritis may substantially reduce cost without adversely affecting the quality of care.
When Verburg et al. designed their randomized clinical trial, published in the June 15, 2016 edition of The Journal of Bone & Joint Surgery, they hypothesized that a mini-midvastus (MMV) approach to total knee arthroplasty (TKA) would yield better outcomes than a conventional approach. However, during short- and mid-term follow-up (up to 5 years postoperatively) on 84 TKAs (42 in each group), the researchers found no relevant clinical or radiographic differences between the two groups, both of which received the same brand of posterior-stabilized implant.
On average, the MMV procedure took 6 minutes longer, and those in the MMV group had better range of motion on postoperative day 3. On the downside, more wound-healing problems such as blisters were observed in the MMV group, especially in large male patients, which the authors attribute to soft-tissue interactions caused by the use of necessarily large components with small incision lengths.
Verburg et al. concluded that “the advantage of the MMV approach was merely a smaller scar,” and they do not recommend MMV or other minimally invasive/quadriceps-sparing approaches for “larger patients or muscular men.”
Many surgeons recommend primary unilateral knee arthroplasty (UKA) over primary total knee arthroplasty (TKA) or tibial osteotomy for younger patients with unicompartmental knee osteoarthritis. Some do so believing that the results of any subsequent revision to TKA (UKA → TKA) will be better than a revision of a primary TKA to a second TKA (TKA → TKA).
A comparative, registry-based study by Leta et al. in the March 16, 2016 JBJS found that both revision categories yielded essentially the same outcomes. The authors found no significant differences between the two strategies in terms of overall implant survival rate or risk of re-revision, or in several patient-reported outcomes: the EuroQol EQ-5D, KOOS, and VAS pain and satisfaction scores. Two notable exceptions were as follows:
- The risk of re-revision was twice as high for TKA → TKA patients who were older than 70 years of age
- UKA → TKAs were more often re-revised because of a loose tibial component and pain alone, while TKA → TKAs were more often re-revised because of deep infection.
With few significant outcome differences, commentator Geoffrey Dervin, MD suggests that “patients facing the initial decision between UKA and TKA should focus more on differences in perioperative morbidity, clinical outcomes, and satisfaction” from the primary procedure rather than on the outcomes of revision should it be required.
The two numbers that you’ll want to remember from the computer model-based cost-effectiveness study by McLawhorn et al. in the January 20, 2016 Journal of Bone & Joint Surgery are $13,910 and $100,000. The first number is an incremental cost-effectiveness ratio (ICER). Here, it’s the estimated added cost per quality-adjusted life year (QALY) for morbidly obese patients (BMI ≥35 kg/m2) with end-stage knee osteoarthritis who undergo bariatric surgery two years prior to total knee arthroplasty (TKA), compared with similar patients who undergo immediate TKA.
The $100,000 is the threshold “willingness to pay” (WTP) that the authors used in their evaluation. Willingness to pay reflects the amount society and healthcare payers such as Medicare and private insurers are willing to pay for a patient to accrue one year lived in perfect health.
Here’s another way to view these findings: Morbidly obese patients who undergo TKA are at increased risk for wound-healing problems, superficial and deep infections, early revision, and poor function. The authors estimated that if bariatric surgery reduces the TKA risks in these patients by at least 16%, on average, the combination of bariatric surgery followed by TKA is more cost-effective than immediate TKA alone.
Because the ICER was much less than the WTP in this model, the authors conclude that “bariatric surgery prior to total knee arthroplasty may be a cost-effective option for improving outcomes in motivated patients with a BMI of ≥35 kg/m2 with end-stage knee osteoarthritis.” However, they are quick to add that “decision modeling cannot simulate reality for every clinical situation.” While this rigorously developed model may provide a decision-making framework for surgeons and policymakers, the authors say, “this approach may be impractical for an individual patient…desiring immediate symptomatic relief from knee osteoarthritis.”
Intraoperative injury to the medial collateral ligament (MCL) is a rare but important complication of total knee arthroplasty (TKA). Surgeons face two basic choices when it happens: intraoperatively converting to a more constrained TKA prosthesis, or primary repair of the MCL followed by protective bracing.
The retrospective review by Bohl et al. in the January 6, 2016 edition of The Journal of Bone & Joint Surgery does not compare those options head-to-head, but with an average follow-up of more than 8 years, it provides solid evidence that intraoperative repair followed by bracing is a successful long-term strategy.
The authors followed 45 TKAs that sustained either an intraoperative midsubstance MCL tear or an avulsion; 35 injuries occurred during a cruciate-retaining procedure, and 10 during a posterior-stabilized TKA. At a mean final follow-up of 99 months:
- There were no symptoms on physical examination of coronal-plane instability
- All patients were capable of community ambulation without an assistive device, and
- The mean HSS knee score had increased from 47 preoperatively to 85.
Five knees (11%) required intervention for stiffness. Although the authors emphasize that “in all cases the brace was set to allow full range of motion of the knee,” bracing may nevertheless have promoted stiffness by inhibiting range of motion in a cohort that included large proportions of obese and morbidly obese patients. This particular finding suggests that range-of-motion exercises should be emphasized after similar surgeries.
Whenever the impact of surgeon volume on patient outcomes for technically complex interventions has been assessed, the following correlation has held: the higher the surgeon volume, the better the patient outcomes. Working with us at the University of Washington in 1997, Dr. Hans Kreder was one of the first to observe this relationship in joint replacement surgery.1 Patients whose hip replacement was performed by a “high-volume” surgeon (>10 hip replacements per year) were significantly less likely to die or have an infection or revision than those whose procedure was performed by a “low-volume” surgeon (<2 hip replacements per year). This makes perfect intuitive sense—the more you do something, the better your skill, and the better the result.
In the study by Liddle et al. in the January 6, 2016 JBJS, the same volume-outcome relationship for knee arthroplasty is confirmed. The relationship is stronger for unicompartmental arthroplasty than it is for total knee arthroplasty (TKA). Again this makes intuitive sense because the “uni” procedure is more dependent on nuanced bone cuts and component placement than TKA, which relies more heavily on the use of guides and jigs.
Does this mean that the end of general orthopaedic surgeons performing joint replacement is at hand? I don’t think so. Many patients will prefer to stay in their community rather than travel to the high-volume surgeon/hospital even after being informed of the volume-outcome relationship. Additionally, joint registries and routine measurement tools now exist that can help lower-volume surgeons monitor their patient outcomes and demonstrate that their results are similar to those of higher-volume surgeons.
Ultimately, all surgeons are responsible for assessing their individual patient outcomes and making that data available for patients who are considering joint arthroplasty.
Marc Swiontkowski, MD
- Kreder HJ, Deyo RA, Koepsell T, Swiontkowski MF, Kreuter W. Relationship between the volume of total hip replacements performed by providers and the rates of postoperative complications in the state of Washington. J Bone Joint Surg [Am] 1997;79(4):485-94.