Robotic-assisted TKA leads to a better prosthesis alignment and a better joint line restoration as compared to conventional TKA: a prospective randomized controlled trial.

PURPOSE: Correct positioning and alignment of the prosthesis is a very important factor for durability of prosthesis and implant survival which is improved with the use of technology in total knee arthroplasty. However, the long-term functional outcomes and survivorship are unclear. For this study, it was hypothesized that mechanical axis alignment of lower limb, post-operative joint line restoration, femoral and tibial component alignment is more accurate with the new handheld semi-active robotic-assisted TKA. METHOD: From April-2019 to March-2020, 60 patients with unilateral knee osteoarthritis who underwent total knee arthroplasties were included in this prospective randomised controlled study. Computer generated randomization was used. Study included 48 female patients and 12 male patients. Pre-operative and post-operative radiographic measurements were done and compared between the two groups. RESULTS: There was a significant difference between two groups with respect to mechanical axis deviation, joint line deviation and coronal alignment of femoral and tibial prosthesis. Mechanical axis deviation > 3° was seen in eight cases (28.5%) in C-TKA group compared to one case (3.1%) in RA-TKA (p 0.019). Joint line deviation of 3.5 mm was noted in C-TKA group as compared to 0.9 mm in RA-TKA group (p < 0.001) which was statistically significant. However, whether this difference of 2.6 mm of joint line elevation between C-TKA and RA-TKA leads to any difference in clinical outcome in terms of knee kinematics and knee flexion needs to be investigated with further studies. Clinically restoring normal joint line is important for improved knee function after primary TKA. No significant difference was noted in femoral component rotation on post-operative computed tomography (CT) scan. CONCLUSION: The novel imageless, handheld semi-autonomous robotic system for TKA is highly accurate with respect to component positioning in coronal plane and mechanical alignment as compared to conventional TKA. Joint line is elevated in conventional TKA but is accurately restored using the robotic-assisted TKA which may lead to better patellofemoral kinematics. LEVEL OF EVIDENCE: I.

Assessment of accuracy of an imageless hand-held robotic-assisted system in component positioning in total knee replacement: a prospective study.

In recent years, robotic technology is becoming more pervasive in joint arthroplasty. The role of robotics in joint replacement surgery is to bring precision and accuracy in bone preparation, implant positioning and soft tissue balancing. However, there is yet to be a study conducted to determine the accuracy of bone preparation done by a new robotic system. The purpose of this study is to evaluate and report on the accuracy of bone cuts using imageless semiautonomous freehand robotic sculpting system, Navio (Smith & Nephew) based on the data provided by the robotic system. Between August 2018 and May 2019, a total of 62 patients were prospectively enrolled in this study. All surgeries were done by the senior author using a medial para-patellar approach and using a posterior stabilised implant (Anthem, Smith & Nephew Inc.). The study included 37 female patients and 25 male patients. The parameters assessed in this study were: (1) mechanical axis, (2) femoral coronal alignment, (3) femoral rotation, (4) femoral sagittal alignment, (5) tibial slope and (6) tibial coronal alignment using paired t test and root mean squared error (RMSE). The robotic system was accurate in achieving the bone cuts as planned in mechanical axis alignment (p = 0.89, RMSE = 0.56), femoral coronal alignment (p = 0.36, RMSE = 0.36), femoral sagittal alignment (p = 0.10, RMSE = 0.44), femoral rotation (p = 0.91, RMSE = 0.11), tibial coronal alignment (p = 0.81, RMSE = 0.24) and tibial slope (p = 0.30, RMSE = 0.37) with the maximum RMSE being 0.56. This study demonstrated that semi-autonomous hand-held robotic system, Navio (Smith & Nephew) for total knee arthroplasty produced accurate component positioning as per plan in all planes. The maximum RMSE was 0.56°.

Comparison of Functional Outcomes of Computer-Assisted vs Conventional Total Knee Arthroplasty: A Systematic Review and Meta-Analysis of High-Quality, Prospective Studies.

BACKGROUND: Computer-assisted navigation system (CAS) in total knee arthroplasty (TKA) has been shown to improve mechanical alignment and prosthesis positioning as compared to conventional TKA. However, the evidence with regard to whether CAS-TKA has better patient function over conventional TKA is not clear. This systematic review and meta-analysis compares functional outcomes of CAS vs conventional TKA at longer follow-up periods. METHODS: This study was conducted in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed, Embase, gray literature, and clinicaltrials.gov were searched up to April 30, 2018. All prospective original studies (only level 1 and 2) that compared functional outcomes of CAS-TKA vs conventional TKA, with minimum 2-year follow-up, were included. The research question and eligibility criteria were established a priori. Pertinent data were extracted and random-effects model was used. RESULTS: A total of 18 studies with 3060 knees were included; of which 1538 underwent TKA with CAS and 1522 underwent conventional TKA. Studies were grouped based on the follow-up reported into: (1) ≥2 years to <5 years; (2) ≥5 years to <8 years; (3) >8 years. Pooled mean Western Ontario and McMaster Universities Osteoarthritis Index scores (P < .001) and Knee Society Score-function score (P = .03) were better in the CAS-TKA group in the 5- to 8-year follow-up. For the remaining follow-ups, there was no difference between the 2 groups. CONCLUSION: The meta-analysis concluded that there is limited evidence that CAS-TKA improves functional outcomes at 5- to 8-year follow-up as measured by Western Ontario and McMaster Universities Osteoarthritis Index and Knee Society Score-function scores. More prospective studies with larger sample size and longer-term follow-up are required to support the trend toward better functional outcomes with CAS.

The presence of concomitant intra-articular injuries and bone bruise does not affect pre-operative knee pain and symptoms in patients undergoing anterior cruciate ligament reconstruction.

PURPOSE: Increased knee pain at the time of anterior cruciate ligament (ACL) reconstruction may predict increased pain post-operatively, a prolonged recovery and a more difficult rehabilitation. The main objective of our study was to identify preoperative factors, such as concomitant intra-articular injuries and bone bruises, that may be associated with increased knee pain and symptoms in patients undergoing ACL reconstruction. METHODS: Patient data was queried from our institution's prospectively maintained ACL reconstruction registry. Two-hundred and seventy patients who underwent primary ACL reconstruction within 3 months of injury were included in the study. Predictors such as demographic characteristics (age, body mass index and gender) and injury characteristics (mechanism of injury, meniscal injury, chondral injury and bone bruise) were recorded. The association between the pre-operative knee injury and Osteoarthritis Outcome Score (KOOS) pain and symptom subscales and the Short Form-36 (SF-36) bodily pain subscale, and the predictors were assessed using logistic regression for categorical variables and linear regression for continuous variables. RESULTS: The mean age of our patient group was 25.4 years with 211 out of 270 (78%) being males. Bone bruise was present in 243 patients (90%), meniscal injury in 165 (61%) patients and chondral injury in 40 (15%) patients. The presence of bone bruise, meniscal injury or chondral injury was not significantly associated with worse preoperative KOOS pain and symptom and SF-36 bodily pain scores. Other factors that were not associated were demographic characteristics (age, BMI and gender) and mechanism of injury. CONCLUSION: The presence of bone bruise and concomitant intra-articular injuries does not affect pre-operative knee pain and symptoms in patients undergoing ACL reconstruction within 3 months of injury. This knowledge would aid the surgeon in pre-operative counselling, and prognostication of post-operative pain and rehabilitation after ACL reconstruction.

Anterior cruciate ligament reconstruction performed within 12 months of the index injury is associated with a lower rate of medial meniscus tears.

PURPOSE: To verify the correlation of time to surgery with the prevalence of concomitant intra-articular injuries detected on arthroscopy during anterior cruciate ligament (ACL) reconstruction. METHODS: The medical records of 653 patients who underwent ACL reconstruction surgery were retrospectively analyzed. Univariate and multivariate logistic regression analysis was performed to identify factors that were associated with the presence of at least one intra-articular injury, medial meniscus tears, lateral meniscus tears and chondral injuries at the time of surgery. Further univariate analysis was conducted to determine the earliest time-point for surgery, after which the rate of concomitant injuries was significantly higher. RESULTS: Longer time to surgery (OR 1.019 95% CI 1.010, 1.028, p = 0.000), male sex (OR 1.695 95% CI 1.074, 2.675 p = 0.023), and higher BMI (OR 1.050 95% CI 1.006, 1.097 p = 0.025) were correlated with a higher prevalence of medial meniscus tears. There was an increased prevalence of medial meniscus tears when surgery was carried out more than 12 months after the index injury (OR 2.274 95% CI 1.469, 3.522, p = 0.000). The correlation between longer time to surgery and chondral injuries approached statistical significance (OR 1.006 95% CI 0.999, 1.012, p = 0.073). However, a longer time to surgery was not associated with an increased prevalence of lateral meniscus tears (OR 1.003 95% CI 0.998, 1.009, p = n.s.). CONCLUSIONS: Longer time to surgery is associated with an increased prevalence of medial meniscus tears in ACL reconstruction. Surgery performed within 12 months of the index injury reduces the prevalence of medial meniscus tears. Prioritizing males and overweight patients for counselling and early intervention can be considered. LEVEL OF EVIDENCE: Therapeutic level III retrospective cohort study.

Use of the 5-Strand Hamstring Autograft Technique in Increasing Graft Size in Anterior Cruciate Ligament Reconstruction.

BACKGROUND: To determine the extent to which a strategy of routinely preparing a 5-strand hamstring autograft would increase graft size in anterior cruciate ligament (ACL) reconstruction. METHODS: A total of 64 patients were enrolled in a prospective randomized controlled study comparing 5-strand and quadrupled semitendinosus-gracilis autografts in single-bundle ACL reconstruction (5-strand group, n = 32; 4-strand group, n = 32). In the 5-strand group, the diameter of the 4-strand construct and the subsequent 5-strand graft used were measured, whereas in the 4-strand group, the diameter of the quadrupled graft used was measured. Quadrupled graft diameter and hamstring tendon lengths were correlated with patient gender, height, weight, and body mass index (BMI). RESULTS: The mean diameter of the final graft used in the 5-strand group was 8.8 ± 0.8 mm, whereas that in the 4-strand group was 7.8 ± 0.7 mm (P < .001). The mean increase in graft size achieved with the use of the 5-strand technique was 1.4 ± 0.3 mm. In the 5-strand group, 24 of 32 (75%) patients had graft diameters exceeding 8 mm compared with 9 of 32 (28%) patients in the 4-strand group (P < .001). Quadrupled graft diameter was significantly correlated with patient height and BMI, whereas the gracilis and semitendinosus lengths were significantly correlated with patient height. CONCLUSIONS: The 5-strand hamstring autograft provides a significantly larger diameter graft compared with the quadrupled hamstring autograft in ACL reconstruction. Graft sizes exceeding 8 mm are achievable in 75% of patients with the routine application of this technique. This is significantly more than that obtained with the standard quadrupled hamstring graft. Hamstring tendon length and quadrupled hamstring graft diameter are also significantly correlated with patient height. LEVEL OF EVIDENCE: Level 1, prospective randomized controlled trial.

Are the Outcomes of Revision Knee Arthroplasty for Flexion Instability the Same as for Other Major Failure Mechanisms?

BACKGROUND: Aseptic loosening, infection, and flexion instability have emerged as the leading etiologies for revision after total knee arthroplasty (TKA). Although studies have reported improved outcomes after revision TKA, the relative functional and clinical outcomes of patients revised for flexion instability and other failure etiologies have not been extensively reported. The aim of the study was to compare the functional and patient-reported outcomes of revision TKA for the common failure etiologies. METHODS: We retrospectively reviewed records of 228 consecutive cases of revision TKA from 2008 to 2014. Revisions performed for aseptic loosening (n = 53), septic revisions (n = 48), and isolated flexion instability (n = 45) with a minimum of 18 months follow-up were included for analysis. Revision for all other etiologies (n = 82) were excluded. The Modified Knee Society Score (KSS), KSS Function, and Western Ontario and McMaster Universities Osteoarthritis Index were recorded for all cases. A 7-point Likert scale was used to record patient's perception of outcomes after revision surgery and analyzed based on etiology. RESULTS: Although all groups showed improvement in outcome after revision TKA, the changes in Modified KSS and KSS-Function varied according to the etiology of failure of the primary procedure with the smallest improvement being reported by the flexion instability group. CONCLUSION: Patients undergoing revision for isolated flexion instability have less improvement in functional outcome as compared with other etiologies. We hypothesize this is due to a higher baseline preoperative knee function in the flexion instability group.

Cadaveric study of anterior and posterior elbow endoscopy portals for endoscopic distal biceps repair: comparative anatomy-at-risk.

PURPOSE: The purpose of this study was to describe neurovascular structures-at-risk during establishment of five portals for access to distal biceps tendon (DBT) in cubital fossa, and to establish relative safety of these portal sites for such access. We hypothesized that all five portals are safe for endoscopic DBT exploration. METHODS: Ten fresh frozen cadaveric elbows were dissected after placement of portals at five potential sites (four anterior, one posterior). Nine neurovascular structures (CV, cephalic vein; LCN, lateral cutaneous nerve; LV, leash of vessels; RN, radial nerve; SRN, superficial radial nerve; PIN, posterior interosseous nerve; RA, radial artery; BA, brachial artery; MN, median nerve) were dissected, and their distances from portal sites were measured. Statistical analysis was performed to determine relative portal safety, and risk of injury to neurovascular structures in relation to each portal was analyzed. RESULTS: Structures that were significantly "at risk" were RA (p = 0.006), SRN (p = 0.002), and PIN (p = 0.004). RA was significantly "at risk" of injury from portal 4 (p = 0.009). Similarly, SRN was "at risk" from portal 3 (p = 0.036), and the PIN was "at risk" from portal 2 (p = 0.003). CONCLUSIONS: Portal 1 (parabiceps portal) was safe for all neurovascular structures, however, portals 2-4 were significantly closer to neurovascular structures. RA, SRN, and PIN were significantly "at risk" as compared to other structures amongst the portals studied. Portal 5 was relatively safe for SRN and PIN. CLINICAL RELEVANCE: Portals 1 (parabiceps portal) and 5 (distal posterior) can be safely placed for endoscopic access to the DBT. Portal 4 (open distal anterior) may be used after careful open dissection and under direct vision. Portals 2 and 3 are not recommended for elbow endoscopy.