New Studies on BMI and Hip Replacement

Obesity is one of the most serious public health problems in the 21st century, and body weight is becoming an important consideration in orthopaedic procedures, especially joint arthroplasty. Two new studies in the February 3, 2016 Journal of Bone & Joint Surgery illuminate the relationship between body mass index (BMI) and hip-arthroplasty outcomes.

In a prognostic study based on registry data (21,361 consecutive hip replacements), Wagner et al. analyzed postsurgical complications and reoperations using BMI as a continuous variableF11.medium. They found strong associations between increasing BMI and increasing rates of reoperation, implant revision or removal, early hip dislocation, and both superficial and deep infections. Although researchers are just starting to examine the efficacy of preoperative interventions to reduce BMI (see related OrthoBuzz post), Wagner et al. suggest that “collaborative interventions between care providers and patients may be undertaken to modify risk factors, such as BMI, before elective procedures.” A commentary on this study lauds the authors for analyzing BMI with a “dose-response” perspective, but the commentators note that “BMI neither remains constant nor follows a predictable trend over time.”

In a separate therapeutic study by Issa et al., clinical and patient-reported outcomes of primary THA were lower in super-obese patients (BMI ≥ 50 kg/m2) than in matched patients with normal BMI (<30 kg/m2). Specifically, after a mean follow-up of six years, compared with the normal-BMI group, the super-obese group had:

  • A 4.5 times higher odds ratio (OR) of undergoing a revision
  • A 7.7 times higher OR of surgical complications, including superficial and deep infections
  • Significantly lower mean values on the Harris hip score, the physical and mental components of the SF-36, and the UCLA activity score.

Despite these between-group findings, super-obese patients still experienced significant clinical improvements compared with their preoperative status. However, they saw an average of 2.5 previous surgeons who refused to perform the procedure prior to being referred to the authors.

3-D Planning Enhances Cup-Placement Accuracy in THA

Screen Shot 2016-02-02 at 8.47.07 AMWhen it comes to acetabular cup positioning during total hip arthroplasty (THA), precision really matters. Malpositioned cups increase the risk of dislocation, early wear, and loosening, among other unwanted outcomes.

In the January 20, 2016 issue of The Journal of Bone & Joint Surgery, Sariali et al. report on results of a randomized trial that compared cup positioning guided by three-dimensional (3-D) visualization tools used intraoperatively (28 patients) with freehand cup placement (28 patients). Cup anteversion was more accurate in the 3-D planning group, and the percentage of anteversion outliers according to the Lewinnek safe zone was lower in the 3-D planning group. Although cup abduction was restored with greater accuracy in the 3-D planning group, the percentage of abduction outliers was comparable between groups.

Interestingly, operative times did not differ between the two groups. The authors note that CT-based navigation, a more expensive technology used to improve acetabular-cup positioning, does increase operative times, although its reported accuracy is higher than that of the 3-D planning technique used in this trial. That apparent tradeoff leads the authors to conclude that “3-D planning may be a good compromise between accuracy on the one hand and extra cost and duration of surgery on the other hand.”

It should also be noted that Sariali et al. did not measure clinical outcomes in this study, so there’s no evidence here that the accuracy enhancements arising from 3-D planning translate into meaningful clinical improvements.

JBJS Reviews Editor’s Choice–Preventing Wrong-Site Surgery

“First do no harm.” Patients undergo operative procedures with the inherent belief that their surgeon will perform the operation in a safe and effective manner, and, certainly, on the correct organ or body part. However, recent data suggest that in orthopaedic surgery alone, 21% of hand surgeons, 50% of spine surgeons, and 8.3% of knee surgeons have performed wrong-site surgery at least once during their career. These are astonishing numbers! Orthopaedic surgeons are at increased risk of performing wrong-site surgery, mainly because of the inherent nature of the musculoskeletal system. Anatomic factors such as laterality, multiple digits, and different spinal levels predispose to wrong-site surgery. Despite the importance of this problem, the incidence of wrong-site surgery in orthopaedics is unknown, primarily because of the lack of data regarding the exact numbers of operative procedures performed.

In this month’s issue of JBJS Reviews, Santiesteban et al. reviewed wrong-site surgery and the history of the development of procedures and practices to avoid it in orthopaedic surgery. Their research shows that, in 1994, the Canadian Orthopaedic Association was the first orthopaedic organization to introduce a surgical safety program designed to reduce wrong-site surgery, known as “Operate Through Your Initials.” Soon thereafter, in 1997, the American Academy of Orthopaedic Surgeons (AAOS) appointed a task force on wrong-site surgery, and, in 1998, the AAOS introduced “Sign Your Site,” a national surgical safety campaign distributed to all hospitals in the United States. By 2004, The Joint Commission became involved and introduced the Universal Protocol, requiring its use for Joint Commission recertification. This protocol recommends the use of three standardized preoperative safety components for every surgical procedure by every surgical team: (1) proper patient identification, (2) marking of the surgical site, and (3) use of a time-out procedure prior to the incision. Wrong-site surgery is preventable, as this initiative was meant to show.

It remains unclear how effective the various adopted methods (including improved consent procedures between the physician and patient, preoperative signing of the appropriate surgical site, time-out protocols, and postoperative debriefings) have been at decreasing the rate of wrong-site surgery. Indeed, it was more than a decade ago that the development of new protocols designed to prevent wrong-site surgery were implemented. Although these protocols have been adopted in most operating rooms, wrong-site surgery and adverse events continue to occur on a weekly basis.

Wrong-site surgery remains a rare but preventable catastrophic surgical event. As noted, the true incidence is unknown. As many as one in four orthopaedic surgeons will perform wrong-site surgery during an active twenty-five-year surgical career, and orthopaedic spine surgeons appear to be at highest risk. Surgeon leadership, commitment, and vigilance are critical to improve surgical patient safety. By adopting these initiatives, wrong-site surgery can be prevented.

Thomas Einhorn, MD

Editor, JBJS Reviews

Whither Meaningful Use?

Meaningful use (MU) Stage 2 and 3 requirements have been a bane of existence for many physician practices, so a collective sigh of relief was heard when acting CMS administrator Andy Slavitt hinted recently that a more streamlined approach to regulating health care IT is coming.

Suggesting that MU as we know it may end altogether sometime in 2016, Slavitt offered few specifics in a speech at the recent JP Morgan Healthcare Conference, saying only that details of the new plan will come out “over the next few months.”

Beth Israel Deaconess Medical Center CIO John Halamka, MD, a frequent blogger on the subject of meaningful use, has said more than once that Stages 2 and 3 tried to do too much too fast, while lauding the functional foundation established by Stage 1. Halamka noted that when MU requirements are heaped on other rules and regulations such as HIPAA, the ACA, ICD-10, and Medicare value-based payment systems, the entire game becomes too complicated and confusing for everyone, including government auditors.

On January 14, 2016, 31 healthcare organizations (including notables such as Geisinger, Intermountain, and Partners) sent a letter to HHS secretary Sylvia Burwell, urging her to “restructure the MU program to fit future care needs and focus on improving interoperability and usability” of EHRs.

Stay tuned…OrthoBuzz will keep you posted.

Atypical Femoral Fractures: An Update

F2.mediumWe posted our first “Case Connections” article about  bisphosphonate-related atypical femoral fractures (AFFs) one year ago. Since then, JBJS Case Connector has published three additional case reports on the same topic, suggesting that it’s time for a revisit. These three recent cases demonstrate that AFFs can occur despite prophylactic intramedullary (IM) nailing of an at-risk femur, that AFFs can present as periprosthetic fractures, and that men taking bisphosphonates—not just women—can experience AFFs.

Bariatric Surgery Prior to TKA for Morbidly Obese Patients?

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.”

JBJS Editor’s Choice: Give Workers’ Comp Patients the Benefit of the Doubt

swiontkowski marc colorIn the January 20, 2016 JBJS prognostic study by Gornet et al., patients with Workers’ Compensation (WC) insurance coverage were compared to a group not covered by that insurance mechanism in regard to outcomes after cervical disc arthroplasty. Multiple studies have been published looking at WC coverage in relation to outcomes after many orthopaedic interventions, including spinal disease, fractures, and soft tissue injuries. The findings have generally identified worse outcomes in terms of pain relief, return to work, and function among WC-covered cohorts.

That was not the case in this analysis by Gornet et al. Only the number of days off before returning to work was different (significantly higher) for WC patients. There were no significant between-group differences in patient-reported outcomes, reoperation rates, complications, or the proportion of patients who returned to work.

I think we can gain some insight into the generally poorer reported outcomes for WC patients by considering that patients with higher functional demand employment experience greater stressors on their musculoskeletal systems. They also often have lower levels of education, which in turn can translate into less control over the work environment. I believe that it is the combination of these two factors that lead some WC patients to emphasize their pain symptoms and functional disability.

Rather than look askance at patients with WC coverage, I think we need to factor in these physical and work-disempowerment issues into our decision making and recommendations. If we do that, we might go beyond making sound clinical recommendations to suggest job retraining or additional classroom education so that the mechanical loads can be lessened and more empowerment at work can be obtained.

Marc Swiontkowski, MD

JBJS Editor-in-Chief

What’s New in Orthopaedic Oncology

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. Here is a summary of selected findings from studies cited in the December 16, 2015 Specialty Update on orthopaedic oncology:

Malignant Primary Bone Tumors

  • A study comparing the efficacy of surgery versus radiation in 465 patients with Ewing sarcoma managed with standardized chemotherapy found lower local failure rates with surgery, but no significant differences in event-free survival, overall survival, or distant metastasis.1
  • A study of 30 long-term survivors of Ewing sarcoma after limb salvage found that, at a mean follow-up of 16 years, 83% of patients were performing athletic activity regularly. Those with pelvic and femoral resections with no reconstruction exercised more hours per week than those with endoprosthetic pelvic reconstruction.2
  • A survival and relapse analysis of 45 locally recurrent osteosarcomas identified a recurrent tumor that was ≥5 cm and metastatic disease at presentation as independent risk factors. Most recurrences were in soft tissues. Early detection and resection with wide negative margins are crucial for optimal outcomes.3
  • A long-term outcome study of 30 patients with recurrent sacral chordoma treated surgically found survival of 89% at two years, 56% at five years, and 19% at ten years. Wide resection gave the best chance of long-term survival, and complete resection of local recurrence gave the best chance of disease control.4

Benign Bone Tumors

  • A study investigating pulmonary metastasis risk factors in 167 patients with giant cell tumor of bone identified local recurrence as the strongest independent predictor of metastasis. Younger patients also had higher metastatic rates.
  • A multicenter study of clinical presentation and outcomes in 126 operatively treated patients with chondroblastoma of the extremities found a local recurrence rate of 4.8% over a minimum two-year follow-up. Findings suggested that local recurrence may be more common in patients with open physes.
  • An investigation of 195 patients with multiple hereditary exostosis found that seven (3.6%) had intraosseous chondroid lesions. Five of those patients developed chondrosarcomas.
  • Curettage, high-speed burring, and bone grafting without other adjuvants in 31 patients with an aneurysmal bone cyst resulted in only one recurrence (3.2%).5

Bone Metastasis and Reconstruction

  • In a study of 125 patients, CT-based structural rigidity analysis of femora to detect impending pathologic fractures had higher sensitivity, specificity, and predictive values than the Mirels classification.6
  • In 111 patients who underwent hemicortical allograft reconstruction of a remaining defect after hemicortical resection of a bone tumor, all of the host bone fractures healed without surgeons having to remove the allograft. The authors recommended hemicortical resections with allograft reconstructions for low- to intermediate-grade tumors.
  • Five-year revision-free survival of conventional total femoral replacements in 40 patients with primary malignant bone tumors was 48%. The most common mechanism of failure was soft-tissue insufficiency.7

References

  1. DuBois SG, Krailo MD, Gebhardt MC, Donaldson SS, Marcus KJ, Dormans J, Shamberger RC, Sailer S, Nicholas RW, Healey JH, Tarbell NJ, Randall RL, Devidas M, Meyer JS, Granowetter L, Womer RB, Bernstein M, Marina N, Grier HE. Comparative evaluation of local control strategies in localized Ewing sarcoma of bone: a report from the Children’s Oncology Group. Cancer. 2015 Feb1;121(3):467-75. Epub 2014 Sep 23.
  2. Hobusch GM, Lang N, Schuh R, Windhager R, Hofstaetter JG. Do patients with Ewing’s sarcoma continue with sports activities after limb salvage surgery of the lower extremity? Clin Orthop Relat Res. 2015 Mar;473(3):839-46.
  3. Takeuchi A, Lewis VO, Satcher RL, Moon BS, Lin PP. What are the factors that affect survival and relapse after local recurrence of osteosarcoma? Clin Orthop Relat Res. 2014 Oct;472(10):3188-95. Epub 2014 Jul 1.
  4. Xie C, Whalley N, Adasonla K, Grimer R, Jeys L. Can local recurrence of a sacral chordoma be treated by further surgery? Bone Joint J. 2015 May;97-B(5):711-5.
  5. Wang EH, Marfori ML, Serrano MV, Rubio DA. Is curettage and high-speed burring sufficient treatment for aneurysmal bone cysts? Clin Orthop Relat Res. 2014Nov;472(11):3483-8. Epub 2014 Jul 22.
  6. Damron TA, Nazarian A, Entezari V, Brown C, Grant W, Calderon N, Zurakowski D,Terek RM, Anderson ME, Cheng EY, Aboulafia AJ, Gebhardt MC, Snyder BD. CT-based structural rigidity analysis is more accurate than Mirels scoring for fracture prediction in metastatic femoral lesions. Clin Orthop Relat Res. 2015 Jul 14.
  7. Sevelda F, Schuh R, Hofstaetter JG, Schinhan M, Windhager R, Funovics PT. Total femur replacement after tumor resection: limb salvage usually achieved but complications and failures are common. Clin Orthop Relat Res. 2015Jun;473(6):2079-87. Epub 2015 Apr 2.

2016 Marks IASP’s Global Year Against Joint Pain

JointPainLogo_IASP_PrintFinal_300 transparentThe International Association for the Study of Pain (IASP) recently launched its 2016 “Global Year Against Pain in the Joints.” In addition to disseminating clinical information focused on joint pain, the campaign seeks to:

  • Connect pain researchers to other health care professionals who interact with joint-pain patients
  • Increase public and governmental awareness of joint pain, and
  • Encourage funders to support research aimed at producing more effective and accessible treatments for people with joint pain.

The Global Year Against Pain in the Joints website includes links to joint pain-related articles from the IASP’s journal Pain and the organization’s six-times-a-year publication Pain: Clinical Updates.  An interview with campaign co-chairs Lars Arendt-Nielsen and Serge Perrot points to promising pain-management research with monoclonal antibodies and biologics directed at anti-nerve growth factor (anti-NGF).

Claiming that “up to 20 percent of joint pain patients do not achieve pain relief after joint replacement,” Dr. Arendt-Nielsen stressed the importance of “partnering with other influential individuals and groups outside of the [IASP]” to achieve the campaign’s goals.

Long-Term Repair Success with MCLs Injured During TKA

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.

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