Efficacy of Intrawound Vancomycin in Prevention of Periprosthetic Joint Infection After Primary Total Knee Arthroplasty: A Prospective Double-Blinded Randomized Control Trial.

BACKGROUND: Periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is a devastating complication. Intrawound vancomycin powder has been shown to reduce infection rates in spine surgery, but its role in arthroplasty remains controversial. This prospective randomized control trial aimed to evaluate the efficacy of intrawound vancomycin in preventing PJI after primary TKA. METHODS: A total of 1,022 patients were randomized to the study group (n = 507, who received 2 grams intrawound vancomycin powder before arthrotomy closure) or to the control group (n = 515, no local vancomycin) with a minimum follow-up of 12-months. The primary outcome was the incidence of PJI or surgical site infection (SSI). Secondary outcomes included associated minor complications such as stitch abscess, persistent wound drainage, and delayed stitch removal. Other parameters evaluated include reoperation rates and incidences of nephrotoxicity. RESULTS: The overall infection rate in 1,022 patients was 0.66%. There was no significant difference in PJI rate in the study group (N = 1; 0.2%) versus the control group (N = 3; 0.58%), P = .264. Reoperation rates in the study group (N = 4; 0.78%) and control (N = 5; 0.97%), and SSI rates in the study (N = 1; 0.2%) and control groups (N = 2; 0.38%) were comparable. The Vancomycin cohort, however, demonstrated a significantly higher number of minor wound complications (n = 67; 13.2%) compared to the control group (n = 39; 7.56%, P < .05). Subgroup analysis showed diabetics in the study group to also have a higher incidence of minor wound complications (24 [14.1%] versus 10 [6.2%]; P < 05]. Multivariate analyses found that vancomycin use (odds ratio = 1.64) and smoking (odds ratio = 1.85) were associated with an increased risk of developing minor wound complications. No cases of nephrotoxicity were reported. CONCLUSIONS: Intrawound vancomycin powder does not appear to reduce PJI/SSI rate in primary total knee arthroplasties, including high-risk groups. Although safe from a renal perspective, intrawound vancomycin was associated with an increase in postoperative aseptic wound complications. Intrawound vancomycin may not be effective in reducing the rate of PJI in primary TKA.

Operating room efficiency for a high-volume surgeon in simultaneous bilateral robotic-assisted total knee arthroplasty: a prospective cohort study.

Robotic-assisted total knee arthroplasty (RATKA) has been shown to achieve more accurate component positioning and target alignment than conventional jig-based instrumentation; however, concerns remain regarding its adoption since it is associated with steep learning curves, higher operational costs, and increased surgical time. This study aims to compare the operating times of three cohorts of patients undergoing simultaneous bilateral TKA, i.e., first 50 RATKA, last 50 RATKA (at the end of 1 year), and 50 conventional TKA. This prospective cohort study was conducted at a single high-volume tertiary care center by a single experienced surgeon on 150 patients (300 knees), who were allotted into three equal cohorts of 50, between February 2020 and December 2021. Simultaneous bilateral TKAs were done in all three groups and operative times recorded. We describe the technique for optimizing the surgical time of SB-RATKA for efficient operative room logistics. The operating times of the two robotic-assisted TKA cohorts were compared with the operating times of the conventional SB-TKA cohort. The mean age of the study population was 59(±6.2) years with the majority of females (82%). The mean coronal deformity was comparable between the cohorts. The mean operating time in the conventional CTKA, initial 50 RATKA, and final 50 RATKA cohorts were 115.56 (±10.7), 127.8 (±26), and 91.66 (±13.5) min, respectively, all of which showed a statistically significant difference (p < 0.001). The mean operating times of the final 50 RATKA at the end of 1 year improved by about 36 min with all the SB-RATKA cases being completed in under 120 min. The efficiency of SB-RATKA improved significantly with time and experience, resulting in shorter operational times within a year, revealing the potential of robotic-assisted surgery to surpass conventional approaches in TKA in terms of operating room efficiency.

Erosion and Failure of the Tibial Post after Posterior-stabilized Total Knee Replacement: A Case Report.

Introduction: Posterior-stabilized (PS) total knee arthroplasty (TKA) prostheses are characterized by an articulation between the polyethylene tibial post and the cam of the femoral component. Tibial post-fractures, traumatic and non-traumatic, are uncommon but catastrophic complications. We report a rare and unusual case of complete atraumatic erosion of the tibial post after PS-TKA. Case Report: We present a case of atraumatic tibial post-failure (complete erosion) in a 73-year-old female after primary TKA. The patient presented with chronic pain, effusion, and instability both in the coronal and sagittal plane over a period of 1 year. There were no signs of component loosening on plain radiography, no fractures, and revealed medial extension laxity on valgus stress views. During revision surgery, polyethylene insert retrieval revealed a completely eroded tibial post, without any obvious fracture. There was no fractured tibial post lying freely in the joint cavity. The patient was subsequently revised with a hinged component due to gross bi-planar instability. Conclusion: In a post-TKR (PS knee) patient with chronic pain and instability, one should consider tibial post-complications after ruling out infection. Chronic instability can cause progressive erosion of the tibial post, which can fail without an obvious fracture. Revision surgery with constrained implants may be needed to manage such cases.

Is it worth the risk? Frailty transition and complications following robotic total knee arthroplasty: A retrospective observational study.

BACKGROUND: Frailty is an underutilized prognostic parameter in the geriatric population. Our study aimed to analyse the frailty incidence, its transition over 1 year and its influence on complication rate in patients undergoing elective robotic-assisted total knee arthroplasty (TKA). METHODS: This was a retrospective study wherein an accumulation of deficits model was used to evaluate frailty of 435 consecutive patients undergoing primary unilateral Mako-assisted cemented TKA between January 2020 and July 2021. Based upon the preoperative values, participants were divided into three groups; non-frail (FI < 0.11), vulnerable (0.11-0.20) and frail (FI > 0.20) states and were followed up for 1 year for change in frailty class, complications, re-admissions and mortality. RESULTS: A total of 435 patients were divided into three groups, non-frail (178), vulnerable (208) and frail (49). Improvement in mean frailty scores was seen in all three groups (P < 0.0001); 21.63% of the vulnerable and 48.97% of the frail participants improved by one frailty class. Multivariate analysis showed the co-relation of change in frailty index (ΔFI) with preoperative FI (r = 0.083) and Knee Society Score (KSS) (r = 0.742). The frail group had a significantly higher re-admission rate over 1 year. When compared with the vulnerable group, the frail group had a higher hazard ratio for readmission (3.12 vs. 0.96) and complications (1.62 vs. 1.26). CONCLUSION: Although frail individuals are at a higher risk for readmissions and perioperative complications, TKA significantly improves the mobility and frailty status of elderly individuals. With explained higher risk of complications, surgeons should not refrain from offering TKA to elderly frail individuals disabled with knee pain.

Intraoperative Periprosthetic Fractures during primary Total knee arthroplasty: Experience from an Asian high-volume arthroplasty centre.

BACKGROUND: Intraoperative periprosthetic fracture (IF) is an under-reported complication in primary total knee arthroplasty (TKA). This study aimed to audit the outcomes and complication rates in patients encountering IF during primary TKA and propose a new classification for its management. METHODS: A nested case-control study was performed at a tertiary referral hospital where 50 patients encountering IF during primary TKA operated by a single surgeon team between January 2016 to May 2021, were compared with 150 (3:1) age-, gender- and implant-matched patients not encountering IF. Demographic data, risk factors, outcomes and complications of both groups were compared at a minimum follow up of 1 year. RESULTS: The incidence of IF was 0.45%, with 44 fractures in the femur (88%), six (12%) in the tibia and none in the patella. Medial collateral ligament avulsion fracture (54.54%) in the femur and medial plateau fracture (66.66%) in the tibia were the most common fracture types. At final follow up, the fracture group had higher rates of 90-day re-admissions (8% vs. 2.66%, P = 0.095), deep infection (4% vs. 0.66%, P = 0.15) and revisions (6% vs. 1.33%, P = 0.06). The mean Knee Society Score was not significantly different between the two groups (152.22 ± 9.25 vs. 161.68 ± 11.22, P = 0.642) with union being achieved in all but one patient at a mean duration of 9.6 weeks. CONCLUSIONS: Patients with severe and fixed deformities have a higher risk for IF. The occurrence of fracture and the complexity of surgery equally contribute to the higher complication rates. Appropriately managed fractures have comparable functional outcomes.

Radiological Evaluation of the Phenotype of Indian Osteoarthritic Knees based on the Coronal Plane Alignment of the Knee Classification (CPAK).

Background: Understanding constitutional alignment of the lower limb is essential to optimize alignment strategies during total knee arthroplasty. The coronal plane alignment of knee (CPAK) classification system was proposed as a comprehensive assessment tool based on coronal alignment and variations in joint line obliquity (JLO). This prospective observational cross-sectional study aimed to evaluate the phenotype of knees in the Indian population based on the CPAK system. Methods: Two cohorts of individuals (250 young healthy volunteers and 250 elderly patients with knee osteoarthritis) underwent radiological assessment with long-leg radiographs and were classified based on the CPAK system. Measurements included the mechanical and arithmetic hip-knee-ankle angles (mHKA, aHKA), joint line obliquity (JLO), lateral distal femoral angle (mLDFA) and medial proximal tibial angle (mMPTA). Knees were grouped into 9 CPAK phenotypes based on aHKA and JLO. Results: A total of 1000 knees were evaluated. In cohort-1 of healthy young adults, most knees were distributed in the CPAK class II phenotype (128 knees, 25.6%) followed by CPAK Type I (106 knees, 21.2%). In cohort-2 of elderly arthritic adults, most knees were distributed in Type I (294 knees, 58.8%) with constitutional varus and apex-distal joint line orientation. Conclusion: The majority of the study population was found to have constitutional varus alignment. In addition, a high proportion of patients in both categories, especially arthritic patients undergoing TKA, were found to have varus alignment with an apex-distal oblique joint line. This classification may help optimize component positioning to restore constitutional alignment and joint line orientation during TKA.

Comparison of patient reported outcomes after robotic versus manual total knee arthroplasty in the same patient undergoing staged bilateral knee arthroplasty.

Background: Robotic-assisted total knee arthroplasty (RATKA) has been proven to improve accuracy of component positioning and reducing alignment target outliers. However, the clinical benefit of robotics is often debated. Recent studies have shown reduced pain and faster recovery in the immediate post-operative period and may be associated with improved PROMs and satisfaction. The aim of this study was to assess PROMs and satisfaction in a unique patient population undergoing bilateral staged TKA to compare manual (MTKA) and RATKA in the same patient. Methods: 55 patients underwent bilateral staged TKA, performed by a single surgeon at a single institute. Patients who underwent TKA for the first knee with manual technique and RATKA for the second side, were eligible for inclusion in the study. Primary outcome assessed was the Oxford Knee Score and secondary outcomes included the Forgotten Joint Score (FJS), patient satisfaction, mean duration for independent ambulation after TKA, and patient perspectives on recovery evaluated with a questionnaire. Results: Both RATKA and MTKA were associated with comparable PROMs. Though RATKA was associated with improved joint perception (Mean FJS after MTKA surgery was 70.3 (SD = 10.66) and significantly lower than the mean FJS after RATKA (73, SD = 10.95, p-value < 0.01), but the difference was not clinically relevant. A higher proportion of patients were more likely to be very satisfied or satisfied after RATKA. A significant proportion of patients felt the knee operated with RATKA was less painful and felt more natural compared to MTKA at final follow-up (p < 0.01). Majority of patients would undergo RATKA again and recommend robotic-TKA to others. Conclusion: Robotic-assisted surgery was associated with improved patient satisfaction, faster independent ambulation compared to manual techniques. PROMs however, were comparable without clinically significant differences. Patients preferred robotic-assisted surgery, with a significantly higher proportion perceiving knee operated by RATKA felt more natural.

Enhanced Mid-Resection Workflow Technique for Severe Varus Deformity Correction Using Robotic-Arm Assisted Total Knee Arthroplasty.

INTRODUCTION: Robotic technology in total knee arthroplasty has been proven to improve accuracy of component positioning, achieve alignment targets, and balance the knee objectively. However, the utility of robotics in correction of severe varus deformities of the knee has not been investigated in detail. The aim of this paper was to establish the utility and describe the technique of robotic-arm assisted total knee arthroplasty (RA-TKA) in achieving pre-balance in severe varus deformities of the knee. MATERIALS AND METHODS: Among the existing Mako (Stryker, Kalamazoo, Michigan) RA-TKA workflows, pre-resection workflow is limited to knees which can be pre-balanced by component positioning according to functional alignment. Mid-resection workflow (distal femur/tibia first) is reserved for complex cases, whereby the extension gap is balanced first. In our experience, both workflows could not achieve pre-balance in severe varus deformities, necessitating the need to develop a novel technique. The ability of the robot to execute precise bone cuts allows for a provisional postero-medial femoral bone cut in flexion, giving access to remove large inaccessible posterior osteophytes and the tight posterior capsule, thus balancing the knee in extension. The flexion gap is subsequently matched to the extension gap by alterations in axial component positioning. CONCLUSION: This novel "enhanced mid-resection workflow" technique establishes the utility of the RA-TKA in balancing severe varus deformities of the knee. We also propose an algorithm which simplifies and helps surgeons choose between the three workflows to pre-balance knees irrespective of the severity of the varus deformity.

Two-Staged Total Knee Arthroplasty in Juvenile Rheumatoid Arthritis with Severe Flexion Deformity: A Case Report.

CASE: Juvenile rheumatoid arthritis (JRA) is associated with severe flexion contracture of the knees disabling a patient's ability to walk. Although various treatment modalities are available in the literature, we report a 2-stage procedure in a case of a 22-year-old female JRA patient with bilateral severe flexion deformity of the knee: stage 1-correction of the flexion contracture deformity by ring fixators and stage 2-total knee arthroplasty (TKA) for arthritis. To the best of our knowledge, no such approach has been reported previously. CONCLUSIONS: An Ilizarov ring fixator is a safe technique for gradual correction of a severe flexion deformity. Subsequent TKA can be performed as a standard procedure.

Unusual Failure of Modular TKA Prosthesis and Screw Migration following Revision Total Knee Arthroplasty.

Introduction: The use of modular implants for revision TKA are ever increasing in number due to their definitive advantage over their monoblock counterparts by providing the surgeon with the versatility needed to achieve equal gaps and manage bone defects. This superiority comes at the cost of certain unique complications attributable to its modular design such as loosening and fractures at the areas of component coupling that are prone to fatigue failure with suboptimal fixation. Case Report: We present a case of modular femoral component failure in a 59-year man of Asian decent after revision TKA secondary to disengagement and migration of the extension stem locking bolt of a Total Condylar-III prosthesis. Patient presented with pain, effusion, and instability 2.5 years after stage-2 revision TKA. Radiographs revealed migration of the femur-stem locking bolt into the joint cavity. The femoral component and stem were loose. The locking bolt was extracted, and he underwent re-revision surgery with revised femoral components. Conclusion: Stem-condylar junction of modern modular TKA implants are prone to early loosening and failure. This diagnosis should be anticipated on serial follow-up radiographs and in patients who complain of sudden onset of instability following revision surgery.

Analgesic efficacy of single-shot adductor canal block versus adductor canal block combined with intra-articular ropivacaine infusion after total knee arthroplasty.

AIMS: Single-shot adductor canal block (ACB) after total knee arthroplasty (TKA) for postoperative analgesia is a common modality. Patients can experience breakthrough pain when the effect of ACB wears off. Local anaesthetic infusion through an intra-articular catheter (IAC) can help manage breakthrough pain after TKA. We hypothesized that combined ACB with ropivacaine infusion through IAC is associated with better pain relief compared to ACB used alone. METHODS: This study was a prospective double-blinded placebo-controlled randomized controlled trial to compare the efficacy of combined ACB+ IAC-ropivacaine infusion (study group, n = 68) versus single-shot ACB+ intra-articular normal saline placebo (control group, n = 66) after primary TKA. The primary outcome was assessment of pain, using the visual analogue scale (VAS) recorded at 6, 12, 24, and 48 hours after surgery. Secondary outcomes included active knee ROM 48 hours after surgery and additional requirement of analgesia for breakthrough pain. RESULTS: The study group (mean visual analogue scale (VAS) pain score of 5.5 (SD 0.889)) experienced significant reduction in pain 12 hours after surgery compared to the control group (mean VAS 6.62 (SD 1.356); mean difference = 1.12, 95% confidence interval (CI) -1.46 to 0.67; p < 0.001), and pain scores on postoperative day (POD) 1 and POD-2 were lower in the study group compared to the control group (mean difference in VAS pain = 1.04 (-1.39 to -0.68, 95% CI, p < 0.001). Fewer patients in the study group (0 vs 3 in the control group) required additional analgesia for breakthrough pain, but this was not statistically significant. The study group had significantly increased active knee flexion (mean flexion 86.4° (SD 7.22°)), compared to the control group (mean 73.86° (SD 7.88°), mean difference = 12.54, 95% CI 9.97 to 15.1; p < 0.014). CONCLUSION: Combined ACB+ ropivacaine infusion via IAC is a safe, reproducible analgesic modality after primary TKA, with superior analgesia compared to ACB alone. Further large volume trials are warranted to generate evidence on clinical significance on analgesia after TKA. Cite this article: Bone Jt Open 2021;2(12):1082-1088.