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.
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 randomized studies cited in the January 21, 2015 Specialty Update on adult reconstructive knee surgery:
Minimizing Blood Loss
–A randomized study of 101 patients undergoing total knee arthroplasty (TKA) found that those receiving topical tranexamic acid (TXA) intra-articularly at the end of surgery had less blood loss and better postoperative hemoglobin levels than those who received a placebo.
–A randomized study of 50 TKA patients and 50 people undergoing total hip arthroplasty found that those receiving TXA had a significantly smaller decline in postoperative hemoglobin levels and needed 39% fewer units of transfused blood than a group that received normal saline solution.
–A randomized study of 126 patients who underwent denervation or not after TKA with unresurfaced patellae found that the denervation group had better pain scores at three months and higher satisfaction and better range of motion at two years.
–Two randomized studies evaluated the impact of patellar eversion versus lateral retraction/subluxation for joint exposure. One study (n=117) found no between-group differences in quadriceps strength at one year, and the other (n=66) found no between-group differences in pain scores or flexion at three months and one year.
Most of the implant-design studies summarized in this Specialty Update can be summed up as “no difference.” Specifically,
–Three randomized studies attempting to evaluate high-flexion TKA designs (n=74, n=278, and n=122) caused the authors of the update to suggest that “the intention of providing greater clinical flexion through high-flex arthroplasty designs does not translate to a meaningful difference in patient outcomes.”
–A randomized study of 124 patients found no differences in maximal post-TKA flexion or functional scores between a group that received a bicruciate-substituting implant and one that received a standard posterior-stabilized design.
–A randomized trial of 34 patients who received prostheses with either highly cross-linked polyethylene or conventional polyethylene found no differences in wear-particle number, size, or morphology after one year.
–A 4- to 6.5-year follow-up study of 56 patients who received either mobile or fixed bearings during TKA found that the mobile-bearing group had greater mean range of motion, but there were no between-group differences in satisfaction or functional scores.
Instrumentation and Technique
–A randomized study of 47 patients whose surgeons used either customized cutting blocks or traditional instruments found no differences in clinical outcomes or mean component alignment. Moreover, surgeons abandoned customized blocks in 32% of the cases because of malalignment.
–A randomized study of 129 patients whose surgical approach was either medial parapatellar or subvastus, all of whom were managed with minimally invasive techniques, found no differences in pain, narcotic consumption, functional outcomes, and Knee Society Scores at postoperative times ranging from three days to three months.
Postoperative Care and Pain Management
–A trial among 249 post-TKA patients who received either one-to-one physical therapy (PT), group-based PT, or a monitored home program found no difference in outcomes at 10 weeks and one year.
–A randomized study of 160 post-TKA patients investigating the effect of continuous passive motion (CPM) machines led the study authors to conclude that CPM is neither beneficial nor cost-effective.
–A small randomized study of pain-management protocols found that a “multimodal” approach that included peri-articular injection led to less pain, less narcotic use, and higher satisfaction for up to six weeks after surgery than a patient-controlled analgesia approach.
–A three-way randomized pain-management study of 100 patients led study authors to recommend against posterior capsule injections and to conclude that “a sciatic nerve block [for TKA] has a minimal effect on pain control.”
–A three-way randomized study of 120 TKA patients found that those receiving preoperative dexamethasone and ondansetron had less nausea, shorter hospital stays, and used less narcotic medication than those who received ondansetron alone. “Dexamethasone should be part of a comprehensive total joint arthroplasty protocol,” the study authors concluded.