Sometimes the findings of well-designed orthopaedic studies are unexpected and counterintuitive—and sometimes they are not. In the latter category are the important but unsurprising results from the Grace et al. database study in the February 19, 2020 issue of The Journal of Bone & Joint Surgery.
The authors set out to determine whether having a specific medical complication after a first total knee arthroplasty (TKA) increased the chance that the same complication would occur after a second TKA performed 90 to 365 days after the first one. Among the specific complications investigated were myocardial infarction (MI), ischemic stroke, respiratory complications, urinary complications, digestive complications, hematoma, deep vein thrombosis (DVT), and pulmonary embolism (PE).
Overall complications after either procedure were low—>90% of the >36,200 patients who underwent bilateral TKAs did not experience any complications during the study period. However, those who had a complication after the first TKA had a significantly higher likelihood of having the same complication after the subsequent, contralateral procedure. Expressed as odds ratios (ORs), the increased probabilities of the same complication recurring after the second procedure were as follows:
- Myocardial infarction—OR, 56.63
- Ischemic stroke—OR, 41.38
- Hematoma—OR, 15.05
- Urinary complications—OR, 11.19
- PE—OR, 11.00
- Respiratory complications—OR, 8.58
- Non-MI cardiac complications—OR, 7.73
- DVT—OR, 7.40
Noting that these findings do not imply causality, the authors nevertheless surmise that “the occurrence of complications after the first replacement likely reflects a burden of comorbidity that predisposes patients to a recurrence of the same complications after the second replacement.” Consequently, Grace et al. suggest that this data could be used to help guide shared decision-making with patients considering staged bilateral TKAs, and that these findings could help identify “a subgroup of patients who may benefit from…targeted optimization strategies prior to the second surgical procedure.”
In previous studies, simultaneous bilateral total knee arthroplasty (TKA) in appropriately selected patients has compared favorably with staged bilateral TKA—in terms of both clinical outcomes and cost. In the December 20, 2017 issue of The Journal of Bone & Joint Surgery, Meehan et al. report on a population-based analysis of 90-day and 180-day postoperative knee stiffness requiring manipulation under anesthesia (MUA) in three patient subgroups: those undergoing simultaneous bilateral, unilateral, and staged bilateral TKA. In this retrospective Level-III study, the authors made appropriate methodological adjustments to account for patients who planned a staged bilateral TKA but did not have the second operation.
In terms of cumulative MUA incidence after 90 and 180 days, rates were lowest in the simultaneous bilateral TKA group. After adjusting for relevant risk factors, Meehan et al. found that, after 90 days, the odds ratio (OR) of undergoing MUA after simultaneous bilateral TKA was significantly lower than that for unilateral TKA and staged bilateral TKA. Similar MUA odds were found among the three groups at 180 days.
The authors also identified significant nonsurgical risk factors for MUA at 90 days. Those included younger age, black race, no chronic comorbidities, and normal weight. The 180-day nonsurgical risk factors for MUA were the same as those for 90 days, with two additions—female sex and Hispanic ethnicity.
While Meehan et al. acknowledge that “there is no uniformity to indications for MUA” and that such decisions are “obviously surgeon- and patient-specific,” they nevertheless conclude that patients undergoing simultaneous bilateral TKA had a significantly lower risk of requiring MUA for stiffness than those in the other two TKA groups studied.
Single-anesthetic bilateral total hip arthroplasty (THA) has had a historically high perioperative complication profile. However, a matched cohort study by Houdek et al. in the January 4, 2017 edition of JBJS comparing single-anesthetic versus staged bilateral THA over four years found no significant differences between the two procedures in terms of:
- Risks of revision, reoperation, or complications (including DVT/PE, dislocation, periprosthetic fracture, and infection; see graph, where blue line represents single-anesthetic and red line indicates staged)
- Perioperative mortality
- Discharge to home versus rehab
The single-anesthetic group (94 patients, 188 hips) experienced shorter total operating room time and hospital length of stay than the matched cohort, and consequently the single-anesthetic approach lowered the relative total cost of care by 27%.
While the Mayo Clinic authors concede the potential for selection bias in this study (e.g., there was no standardized protocol for determining eligibility for inclusion in either group), they say that they currently consider single-anesthetic bilateral THA for patients with bilateral coxarthrosis who are <70 years of age, relatively healthy, and/or have bilateral hip contractures that would make rehabilitation difficult.