The Difficult Primary Total Knee Arthroplasty.

Primary total knee arthroplasty (TKA) for the treatment of knee arthritis has substantially increased over the past decade. Because of its success, the indications for primary TKA have expanded to include younger patients who are more active, elderly patients who have multiple comorbidities, and patients who have more complex issues, such as posttraumatic arthritis and severe deformity. TKA also has been used to salvage failed unicondylar arthroplasty and osteotomies about the knee. Exposure may be challenging and outcomes may not be as successful in patients with soft-tissue contractures, such as a stiff knee, who undergo TKA. Bone graft or augments may be required to correct deformity and attain proper knee alignment in patients who have a substantial varus or valgus deformity. TKA is somewhat challenging in patients who have deformity, bone loss, contracture, or multiple comorbidities, or have had prior surgery; therefore, it is necessary for surgeons to be aware of some general principles that may help minimize complications and improve outcomes.

A prospective, longitudinal study of patient satisfaction following total knee arthroplasty using the Short-Form 36 (SF-36) survey stratified by various demographic and comorbid factors.

The purpose of this study was to evaluate the longitudinal variations in SF-36 physical and mental scores and the effects of demographics and comorbidities after TKA. This prospective study evaluated 108 men and 173 women who had a mean age of 66 years. All patients were followed for a minimum of five years and SF-36 physical and mental component scores were evaluated longitudinally. Physical scores steadily increased during the first year whereas mental component scores initially decreased in the first six weeks and then subsequently increased and both plateaued at one year. Demographic and social factors had a greater effect on physical component scores and comorbidities were more predictive of poor mental scores. Surgeons should counsel their patients that they will likely perceive the full benefit of TKA by one year, but in the first months may perceive worse outcomes.

Preoperative Activity Level an Indicator of Postoperative Functional Outcomes with a Contemporary Revision Total Knee System.

As the population requiring revision total knee arthroplasty (rTKA) grows, varying preoperative conditions may need to be considered when attempting to predict postoperative outcomes. Considering preoperative activity levels may help manage the expectations of patients. The purpose of this study was to analyze the outcomes of low- and high-activity subgroups of patients receiving a contemporary rTKA. One hundred and eighty-one rTKA patients enrolled in a prospective multicenter study were evaluated over a minimum follow-up of 2 years postoperatively. Patients were divided into two groups based on the preoperative activity level using the Lower Extremity Activity Scale. Patients scoring between 1 and 7 were classified as "Low Activity" (LA; N = 105) and patients scoring 8 to 18 were classified as "High Activity" (HA; N = 76). Clinical outcomes were evaluated, with an additional quality-of-life analysis completed utilizing SF-6D (6-dimension short form) scores obtained through a method described by Brazier et al and analyzed for effect size. There were no significant differences in age or body mass index between the groups. Postoperative improvement in both groups were similar in the Knee Society score (KSS), but the LA group showed larger increases in the KSS functional assessment at 6 months (16.2) and 2 years (34.8). There was a statistically significant effect (0.96, p = 0.0006) seen in the LA group at 1 year, in conjunction with a higher SF-6D outcome. The current study population displayed significant improvement in functional patient outcomes following rTKA regardless of preoperative activity level and function. Patients with lower preoperative activity levels demonstrated greater cumulative functional and quality-of-life improvements. This suggests that a lower preoperative activity level may be related to a poorly functioning knee and that rTKA has the potential to improve overall activity levels and function. Low preoperative function should not disqualify patients for rTKA.

Early versus delayed postoperative adductor canal block in total knee arthroplasty.

Background: We hypothesized that patients who received an adductor canal block (ACB) in the operating room following unilateral total knee arthroplasty would have a lower oral morphine milligram equivalent (MME) consumption during the postanesthesia care unit (PACU) phase 1 recovery period compared to patients who received an ACB in the PACU. Methods: This was a retrospective cohort study of patients who underwent robotic-assisted unilateral total knee arthroplasty under general anesthesia between March 1, 2020, and February 28, 2021, and received postoperative ACB either in the operating room or the PACU. Results: A total of 36 and 178 patients received postoperative ACB in the operating room and PACU, respectively, and had median and interquartile range MME consumption in the PACU of 22.5 (20-40) mg and 30.0 (20-40) mg (P = 0.76), respectively. Patients who had an ACB performed in the operating room and PACU had median and interquartile ranges of time spent in the PACU of 101 (75-178) minutes and 186 (125-272) minutes (P < 0.01), respectively. Conclusion: Patients who received an ACB in the operating room did not have a lower OME consumption than patients who received an ACB in the PACU but did have a shorter PACU length of stay.

Revision total hip arthroplasty using a modular femoral implant in Paprosky type III and IV femoral bone loss.

The purpose of this study was to compare results of patients with Paprosky type I and II femoral defects vs type IIIA, IIIB, and IV defects in patients undergoing revision hip arthroplasty. There were 64 patients in the group with type I and II defects with an average age of 68 years. There were 52 patients with Paprosky type IIIA, IIIB, and IV defects with an average age of 67 years. There were 8 intraoperative fractures in the type III and IV group, whereas there were 9 in the type I and II group. There were no differences between the 2 groups with respect to subsidence, loosening, dislocation, infection, and medical complications. Survivorship for the whole group was 96.9% at 5 years. Modular femoral implants provide several intraoperative options to restore leg length, offset, and stability despite femoral defects. We did not realize a higher failure rate in patients with type III or IV defects.

Efficacy of Liposomal Bupivacaine Compared with Multimodal Periarticular Injections for Postoperative Pain Control following Total Knee Arthroplasty.

Single-dose long-acting periarticular anesthetics have been shown to be an effective method of postoperative analgesia in total knee arthroplasty (TKA). This study retrospectively compares the efficacy of multimodal periarticular injection consisting of a combination of ropivacaine, duramorph, epinephrine, and toradol (HC) with liposomal bupivacaine (LB) periarticular injection in TKA. This study was a retrospective matched comparative chart review of two cohorts of patients who underwent TKA within a single health care system and cared for by one provider. We compared 22 patients who were treated with LB intraoperatively (LBG) with 41 matched controls who were treated with HC periarticular injection (HCG). These cases were retrospectively reviewed at 0 to 6, 6 to 12, 12 to 24, 24 to 48, and 48 to 72 hours. We reviewed pain scores and opioid use per the preceding time period, total opioid use, length of stay (LOS), and wound complications between the two groups. The two groups showed no statistical difference in total opioids used. In both the 6- to 12-hour and 12- to 24-hour intervals, the LBG required significantly more opioids than the HCG, with p-values of 0.0039 and 0.0061, respectively. Pain scores were not significantly different for any time period. We found no difference in LOS. The LBG tended to have lower doses of antiemetics than the HCG. No significant difference was found in postoperative pain scores and total opioid use between LB and multimodal periarticular intraoperative injections in TKA. Our data demonstrated decreased opioid consumption in the HC group compared with the LB group in both the 6- to 12-hour and 12- to 24-hour time intervals postoperatively. At our institution, LB costs US$314.99, whereas HC costs US$95.

Use of a Flexible Intramedullary Rod and its Influence on Patient Satisfaction and Femoral Size in Total Knee Arthroplasty.

Improper femoral component size remains a source of multiple postoperative complications following total knee arthroplasty (TKA). However, the use of a flexible intramedullary (IM) rod may help optimize femoral component size and therefore improve outcomes. The purpose of this study was to assess (1) patient-reported functional outcomes, (2) overall quality of life, and (3) changes in implant sizing associated with total knee arthroplasties performed with a flexible IM rod compared to a conventional, rigid rod. We reviewed 277 patients who had surgery using the rigid rod and 364 using the flexible rod to determine the tendency of each rod for selecting particular component sizes. Additionally, 100 patients were prospectively randomized (1:1) to the flexible or the conventional rigid IM rod cohorts. Outcomes were assessed using Knee Society scores (KSSs), SF-36 physical scores, and SF-36 mental scores preoperatively and at 6 weeks, 3 months, 1 year, and 2 years postoperatively. The retrospective arm of the study showed that the flexible IM rod cohort tends to have smaller component sizes than their conventional counterparts. In the prospective phase of the study, the increase in clinical KSSs from preoperative levels was better in the flexible rod cohort (160% vs. 143% increases, respectively). The functional KSSs had slightly higher increases in the flexible rod cohort from their preoperative levels (68% vs. 62% increases, respectively). With both clinical and functional KSSs, the flexible rod cohort had a higher score than the rigid rod cohort at all follow-up points. There was better postoperative range of motion (ROM) in the flexible rod cohort (28% vs. 22% increases, respectively). The SF-36 physical scores were slightly different, with the flexible IM rod cohort having a more marked improvement in scores (64% vs. 46% increases, respectively). The SF-36 mental score had a slightly better improvement at latest follow-up in the flexible IM rod cohort (12% vs. 6% increases, respectively). Those patients who underwent TKA using a flexible IM rod had better improvements in their patient-reported outcomes and decreased risk of oversizing the femoral component. The use of such a rod is not detrimental to outcomes and may have a positive impact on outcomes. Future studies should focus on alignment and long-term outcomes associated with the use of a flexible rod.

Mechanical bone strength of the tibial resection surface at increasing distance from the joint line in total knee arthroplasty.

Few articles have addressed the bone strength of the proximal tibia. This study attempts to quantify the compressive strength of bone in the proximal tibia of human cadaveric knees at increasing distance from the joint surface. Sixteen fresh-frozen human cadaveric knees were tested. The proximal tibia was sequentially sectioned into 1-cm slices, starting 2 mm below the chondral surface of the medial tibial plateau. Four slices were obtained from each knee. Each slice was then loaded to failure under an axial load. The proximal slice of bone had a significantly higher average maximum load to failure than the more distal slices. The second, third, and fourth slices of bone withstood 77%, 61%, and 73% of the average load of the proximal slice, respectively. This study was designed to simulate how the proximal tibia is loaded under an uncemented tibial base plate after total knee arthroplasty. The results are in agreement with previous studies that have shown the proximal 1 cm of tibial bone to have the highest resistance to compressive loads. Previous studies on the bone strength of the proximal tibia have focused on more proximal portions of bone than the current study. This study demonstrates that the load to failure of tibial resection surface decreases significantly with increasing distance from the joint line until the 4th cm of bone beneath the joint line is encountered. This information may play a role in surgical decision making and implant design.

Clinical and patient-reported outcomes of primary TKA with a single-radius design.

Total knee arthroplasty (TKA) is a cost-effective procedure used to treat degenerative knee disease with excellent long-term outcomes. However, TKA has not always resulted in excellent functional and patient satisfaction outcomes, partly due to the use of prostheses that did not reproduce natural knee kinematics. Due to a paucity of reports on single-radius designs, the authors evaluated the clinical and patient-reported outcomes of primary TKA in patients who had received a single-radius prosthesis. A total of 287 TKAs from 7 centers were prospectively evaluated. Mean follow-up was 5 years, with each patient undergoing year re-evaluation. Kaplan-Meier implant survivorship was 99.7% at a final follow-up of 7 years. The total reoperation rate was 1.4%. Clinical outcomes demonstrated significant improvements in Knee Society, Short Form 36, and activity scores at a mean follow-up of 5 years. The authors believe that various features of this prosthesis may have contributed to these excellent outcomes. Further longer-term studies are necessary to better evaluate these outcomes.

A proteomic study of protein variation between osteopenic and age-matched control bone tissue.

The focus of this study was to identify changes in protein expression within the bone tissue environment between osteopenic and control bone tissue of human femoral neck patients with osteoarthritis. Femoral necks were compared from osteopenic patients and age-matched controls. A new method of bone protein extraction was developed to provide a swift, clear view of the bone proteome. Relative changes in protein expression between control and osteopenic samples were quantified using difference gel electrophoresis (DIGE) technology after affinity chromatographic depletion of albumin and IgG. The proteins that were determined to be differentially expressed were identified using standard liquid chromatography mass spectrometry (LC/MS/MS) and database searching techniques. In order to rule out blood contamination, blood from age-matched osteoporotic, osteopenic and controls were analyzed in a similar manner. Image analysis of the DIGE gels indicated that 145 spots in the osteopenic bone samples changed at least ± 1.5-fold from the control samples (P < 0.05). Three of the proteins were identified by LC/MS/MS. Of the proteins that increased in the osteopenic femurs, two were especially significant: carbonic anhydrase I and phosphoglycerate kinase 1. Apolipoprotein A-I was the most prominent protein that significantly decreased in the osteopenic femurs. The blood samples revealed no significant differences between groups for any of these proteins. In conclusion, carbonic anhydrase I, phosphoglycerate kinase 1 and apolipoprotein A-I appeared to be the most significant variations of proteins in patients with osteopenia and osteoarthritis.