Administration of Low-dose Hyperbaric Bupivacaine for Spinal Anesthesia in the Setting of Outpatient Arthroplasty

INTRODUCTION

With the rise of ambulatory surgery centers (ASCs), rapid motor and sensory recovery after anesthesia is crucial. The purpose of this study was to evaluate the safety and efficacy of low-dose single-shot hyperbaric bupivacaine for spinal anesthesia (SA) for patients undergoing outpatient arthroplasty.

METHODS

Data were reviewed from a single ASC from 2018 to 2020 for two arthroplasty-trained surgeons for all patients with primary arthroplasties that had administration of low-dose hyperbaric bupivacaine. Data collected from the ASC records were then further evaluated for total spinal block time, length of blockade, time to discharge criteria, visual analog scale (VAS) scores, and time to discharge.

RESULTS

Two hundred twenty-seven patients undergoing 244 primary arthroplasties received SA with low-dose hyperbaric bupivacaine. The volume of 0.75% bupivacaine varied: 115 patients received 0.8 mL (6 mg), 111 patients received 1.0 mL (7.5 mg), and 17 patients received 1.2 mL (9 mg). Total SA time averaged 144 minutes with a mean of 30 minutes from post anesthesia care unit arrival to motor recovery. The mean time from post anesthesia care unit arrival to discharge criteria was 89 minutes. The average VAS at discharge was 1.44; the average VAS on POD1 was 3.0. No episodes of urinary retention and no reports of transient neurologic symptoms were noted in the study population.

CONCLUSION

Low-dose, single-shot hyperbaric bupivacaine SA is an effective option in the ASC for arthroplasty, providing a fast return of motor function, facilitating rapid discharge, and is safe with a relatively low-risk profile.

Intra-operative laxity and balance impact 2-year pain outcomes in TKA: a prospective cohort study

PURPOSE

The objective of this study was to determine if intra-operatively measured joint gaps are associated with 2-year pain outcomes in total knee arthroplasty (TKA) and whether balance and laxity windows could be defined throughout flexion to optimize 2-year pain outcomes. Our hypothesis is that intra-operative joint gaps are associated with 2 year post-operative pain outcome.

METHODS

A prospective study investigating 310 robotically assisted TKAs was performed. Final intra-operative joint gap data were recorded using a digital tensioner and component alignment data were recorded by the robotics system. Patient demographics and Knee Injury and Osteoarthritis Outcome Score (KOOS) were recorded pre-operatively and KOOS and Hospital for Special Surgery (HSS) satisfaction were recorded at 2 years post-op. A random search Simulated Annealing (SANN) optimisation algorithm was used to determine global optimum laxity and balance windows at different flexion angles which maximized the 2-year KOOS pain scores. The windows were combined to determine the impact of achieving optimal laxity and balance throughout flexion. To improve clinical utility, boundaries identified by the SANN algorithm were rounded to the nearest 0.5 mm before statistical analysis.

RESULTS

Laxity and balance windows were defined in extension (Med lax: -2.0 to 2.5 mm, Lat lax: -0.5 to 2.5 mm, Balance: -3.0 to 0.0 mm), mid-flexion (Med lax: -1.0 to 2.5 mm, Lat lax: -0.5 to 3.0 mm, Balance: -2.0 to 2.0 mm), and flexion (Med lax: -2.0 to 3.5 mm, Lat lax: -2.0 to 1.5 mm, Balance: -3.0 to 3.0 mm). When all windows were satisfied, the greatest difference in KOOS pain score was observed (100.0 vs 94.4, p < 0.0001). The highest percentage of knees satisfying the Patient Acceptable Symptom State (PASS) for KOOS pain was also observed in knees which satisfied all windows compared to knees which did not (93% vs 71%, p = 0.0009). The proportion of knees which satisfy the PASS threshold decreased in knees which only satisfied 1-3 (29%) or 4-6 (69%) windows (p ≤ 0.0018). No optimal windows were found between component alignment and KOOS pain outcome (p ≥ 0.1180). High satisfaction was found across all groups (≥ 95%).

CONCLUSION

Intra-operatively measured joint gaps are associated with all KOOS sub-score outcomes at 2 years after TKA. Optimal windows for a clinically relevant improvement in post-operative KOOS pain were defined for laxity and balance but not for alignment indicating balance may have a greater impact on outcome than alignment.

LEVEL OF EVIDENCE

II.

Improved total knee arthroplasty pain outcome when joint gap targets are achieved throughout flexion

PURPOSE

Achieving a balanced knee is accepted as an important goal in total knee arthroplasty; however, the definition of ideal balance remains controversial. This study therefore endeavoured to determine: (1) whether medio-lateral gap balance in extension, midflexion, and flexion are associated with improved outcome scores at one-year post-operatively and (2) whether these relationships can be used to identify windows of optimal gap balance throughout flexion.

METHODS

135 patients were enrolled in a multicenter, multi-surgeon, prospective investigation using a robot-assisted surgical platform and posterior cruciate ligament sacrificing gap balancing technique. Joint gaps were measured under a controlled tension of 70-90 N from 10°-90° flexion. Linear correlations between joint gaps and one-year KOOS outcomes were investigated. KOOS Pain and Activities of Daily Living sub-scores were used to define clinically relevant joint gap target thresholds in extension, midflexion, and flexion. Gap thresholds were then combined to investigate the synergistic effects of satisfying multiple targets.

RESULTS

Significant linear correlations were found throughout extension, midflexion, and flexion. Joint gap thresholds of an equally balanced or tighter medial compartment in extension, medial laxity ± 1 mm compared to the final insert thickness in midflexion, and a medio-lateral imbalance of less than 1.5 mm in flexion generated subgroups that reported significantly improved KOOS pain scores at one year (median ∆ = 8.3, 5.6 and 2.8 points, respectively). Combining any two targets resulted in further improved outcomes, with the greatest improvement observed when all three targets were satisfied (median ∆ = 11.2, p = 0.002).

CONCLUSION

Gap thresholds identified in this study provide clinically relevant and achievable targets for optimising soft tissue balance in posterior cruciate ligament sacrificing gap balancing total knee arthroplasty. When all three balance windows were achieved, clinically meaningful pain improvement was observed.

LEVEL OF EVIDENCE

Level II.

Impact of intra-operative predictive ligament balance on post-operative balance and patient outcome in TKA: a prospective multicenter study

INTRODUCTION

New technologies exist which may assist surgeons to better predict final intra-operative joint balance. Our objectives were to compare the impact of (1) a predictive digital joint tensioning tool on intra-operative joint balance; and (2) joint balance and flexion joint laxity on patient-reported outcomes.

MATERIALS AND METHODS

Two-hundred Eighty patients received posterior cruciate ligament sacrificing TKA with ultra-congruent tibial inserts using a robotic-assisted navigation platform. Patients were divided into those in which a Predictive Plan with a digital joint-tensioning device was used (PP) and those in which it was not (NPP), in all cases final post-operative joint gaps were collected immediately before final implantation. Demographics and KOOS were collected pre-operatively. KOOS, complications and satisfaction were collected at 3, 6 and 12 months post-operatively. Optimal balance difference between PP and NPP was defined and compared using area-under-the-curve analysis (AUC). Outcomes were then compared according to the results from the AUC.

RESULTS

AUC analysis yielded a balance threshold of 1.5 mm, in which the PP group achieved a higher rate of balance throughout flexion compared to the NPP group: extension: 83 vs 52%; Midflexion: 82 vs 55%; Flexion 89 vs 68%; Flexion to Extension 80 vs 49%; p ≤ 0.003. Higher KOOS scores were observed in knees balanced within 1.5 mm across all sub-scores at various time points, however, differences did not exceed the minimum clinically important difference (MCID). Patients with > 1.5 mm flexion laxity medially or laterally had an increased likelihood of 2.2 (1.1-4.4) and 2.5 (1.3-4.8), respectively, for failing to achieve the Patient Acceptable Symptom State for KOOS Pain at 12 months. Patient satisfaction was high in both the PP and NPP groups (97.4 and 94.7%, respectively).

CONCLUSIONS

Use of a predictive joint tensioning tool improved the final balance in TKA. Improved outcomes were found in balanced knees; however, this improvement did not achieve the MCID, suggesting further studies may be required to define optimal balance targets. Limiting medial and lateral flexion laxity resulted in an increased likelihood of achieving the Patient Acceptable Symptom State for KOOS Pain.

Effectiveness of Bupivacaine Liposome Injectable Suspension for Postoperative Pain Control in Total Knee Arthroplasty: A Prospective, Randomized, Double Blind, Controlled Study

BACKGROUND

We compared the effectiveness of liposomal bupivacaine to ropivacaine, each as part of multimodal pain management, in total knee arthroplasty (TKA) postoperative pain control.

METHODS

This prospective, double blind study randomized 96 TKA patients into a control group (periarticular injection of ropivacaine, ketorolac, morphine, and epinephrine in saline; 100cc) or an experimental group (periarticular injection of bupivacaine, ketorolac, morphine, and epinephrine in saline; 80cc plus 1.3% liposomal bupivacaine 20cc; total injection 100cc). The postoperative use of narcotics, visual analog pain scores, hours to ambulate 100 feet, and length of hospital stay were recorded.

RESULTS

There was no significant difference between the two groups (control N = 49, experiment N = 47) in mean narcotic use per hour, total narcotic use during hospital stay, time to ambulate 100 feet, length of hospital stay, or visual analog score for pain postoperatively.

CONCLUSION

There is no benefit in the use of liposomal bupivacaine compared with ropivacaine for postoperative pain control in TKA.

Significant weight loss may delay or eliminate the need for total knee replacement

A 48-year-old morbidly obese woman with a left medial meniscal tear and moderately severe degenerative joint disease (DJD) reported for 14-month follow-up visit from arthroscopic surgery. She reported a resolution of pain, swelling and an improved range of motion (ROM). The patient was first evaluated 14 months ago, and at that time was considered a strong candidate for total knee replacement due to her limited (ROM), knee pain, swelling and functional impairment. At a 3 month visit prior to her initial evaluation the patient voluntarily enrolled in a nutritional and exercise program overseen by a licensed personal trainer and kinesiologist. At her final evaluation 14 months later, it was noted that in addition to her improved knee symptoms, the patient lost 15% of her initial bodyweight and exhibited significant gains in quadriceps strength. Her clinical exam and imaging suggested an arrest of progression of her joint disease. It was decided mutually by the patient and physician that she was no longer a candidate for total knee replacement surgery. Although the association between her weight loss and her knee DJD can only be hypothesized, this case report may highlight the need to discuss weight loss as an alternative treatment modality for end stage DJD.

Improved accuracy of alignment with patient-specific positioning guides compared with manual instrumentation in TKA

BACKGROUND

Coronal malalignment occurs frequently in TKA and may affect implant durability and knee function. Designed to improve alignment accuracy and precision, the patient-specific positioning guide is predicated on restoration of the overall mechanical axis and is a multifaceted new tool in achieving traditional goals of TKA.

QUESTIONS/PURPOSES

We compared the effectiveness of patient-specific positioning guides to manual instrumentation with intramedullary femoral and extramedullary tibial guides in restoring the mechanical axis of the extremity and achieving neutral coronal alignment of the femoral and tibial components.

METHODS

We retrospectively reviewed 569 TKAs performed with patient-specific positioning guides and 155 with manual instrumentation by two surgeons using postoperative long-leg radiographs. For all patients, we assessed the zone in which the overall mechanical axis passed through the knee, and for one surgeon's cases (105 patient-specific positioning guide, 55 manual instrumentation), we also measured the hip-knee-ankle angle and the individual component angles with respect to their mechanical axes.

RESULTS

The overall mechanical axis passed through the central third of the knee more often with patient-specific positioning guides (88%) than with manual instrumentation (78%). The overall mean hip-knee-ankle angle for patient-specific positioning guides (180.6°) was similar to manual instrumentation (181.1°), but there were fewer ± 3° hip-knee-ankle angle outliers with patient-specific positioning guides (9%) than with manual instrumentation (22%). The overall mean tibial (89.9° versus 90.4°) and femoral (90.7° versus 91.3°) component angles were closer to neutral with patient-specific positioning guides than with manual instrumentation, but the rate of ± 2° outliers was similar for both the tibia (10% versus 7%) and femur (22% versus 18%).

CONCLUSIONS

Patient-specific positioning guides can assist in achieving a neutral mechanical axis with reduction in outliers.