Validating the capture rate of revisions by the New Zealand ACL Registry: An analysis of all-cause reoperation following primary ACL reconstruction.

PURPOSE: To validate the New Zealand Anterior Cruciate Ligament (ACL) Registry's capture rate of revisions by cross-referencing Registry data with reoperations data recorded by the Accident Compensation Corporation (ACC) and identify risk factors for all-cause reoperation. METHODS: Primary ACL reconstructions performed between April 2014 and September 2019 were individually matched on a record-by-record basis between the two databases. The ACC database was used to identify patients who underwent a reoperation with manual review of operation notes to identify whether a revision or other procedure was performed. This was combined with the number of revisions separately recorded in the New Zealand ACL Registry, which was used as the denominator value to calculate the Registry's capture rate of revisions. Patient and surgical data recorded in the Registry were analysed to identify independent predictors for all-cause reoperation. RESULTS: A total of 8046 primary ACL reconstructions were matched between the New Zealand ACL Registry and the ACC databases. The reoperation rate was 8.9% (n = 715) at a mean follow-up of 2.5 years. Meniscal-related procedures were the most common reoperation (n = 299, 3.7%), followed by revision ACL reconstruction (n = 219, 2.7%), arthrofibrosis (n = 185, 2.3%), cartilage (n = 56, 0.7%) and implants (n = 32, 0.4%). The New Zealand ACL Registry captured 96% of revisions. Younger age (hazard ratio [HR] > 1.4, p < 0.001), earlier surgery (HR > 1.3, p = 0.05), concurrent meniscal repair (medial meniscus HR = 1.9, p < 0.001 and lateral meniscus HR = 1.3, p = 0.022) and hamstring tendon autografts (HR = 1.4, p = 0.001) were associated with a higher risk of reoperation. CONCLUSION: The New Zealand ACL Registry captured 96% of revisions. Risk factors for all-cause reoperation included younger age, earlier surgery, meniscal repair and hamstring tendon autografts. LEVEL OF EVIDENCE: Level III.

Risk factors for reoperation for arthrofibrosis following primary anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study is to identify the rate and risk factors for a reoperation for arthrofibrosis following primary anterior cruciate ligament (ACL) reconstruction. METHODS: Prospective data recorded in the New Zealand ACL Registry were cross-referenced with data from the Accident Compensation Corporation (ACC). Primary ACL reconstructions performed between April 2014 and May 2021 were analysed. The ACC database was used to identify patients who underwent a reoperation for a diagnosis of arthrofibrosis. Multivariable survival analysis was performed to compute adjusted hazard ratios (aHR) and 95% confidence intervals. RESULTS: A total of 12,296 primary ACL reconstructions were analysed, of which 230 underwent a reoperation for arthrofibrosis (1.9%) at a mean follow-up of 3.6 years. A higher risk of arthrofibrosis was observed in females (aHR = 1.76, p = 0.001), patients with a history of previous knee surgery (aHR = 1.82, p = 0.04) and when a transtibial drilling technique was used (aHR = 1.53, p = 0.03). ACL reconstruction >6 months after injury had the lowest rate of arthrofibrosis (1.3%, aHR = 0.45, p = 0.01). There was no difference in risk between early surgery within 6 weeks versus delayed surgery between 6 weeks and 6 months after injury (2.9% versus 2.1%, aHR = 0.78, not significant). CONCLUSION: Female sex, previous knee surgery and a transtibial drilling technique increased the risk of reoperation for arthrofibrosis. Early surgery within 6 weeks of injury was not associated with an increased risk when compared with surgery between 6 weeks and 6 months after injury. LEVEL OF EVIDENCE: Level III.

Meniscal repair failure following concurrent primary anterior cruciate ligament reconstruction: results from the New Zealand ACL Registry.

PURPOSE: This study aimed to identify the risk factors for meniscal repair failure following concurrent primary anterior cruciate ligament (ACL) reconstruction. METHODS: Prospective data recorded by the New Zealand ACL Registry and the Accident Compensation Corporation were reviewed. Meniscal repairs performed during concurrent primary ACL reconstruction were included. Repair failure was defined as a subsequent reoperation involving meniscectomy of the repaired meniscus. Multivariate survival analysis was performed to identify the risk factors for failure. RESULTS: A total of 3,024 meniscal repairs were analysed with an overall failure rate of 6.6% (n = 201) at a mean follow-up of 2.9 years (SD 1.5). The risk of medial meniscal repair failure was higher with hamstring tendon autografts (adjusted HR [aHR] = 2.20, 95% CI 1.36-3.56, p = 0.001), patients aged 21-30 years (aHR = 1.60, 95% CI 1.30-2.48, p = 0.037) and in patients with cartilage injury in the medial compartment (aHR = 1.75, 95% CI 1.23-2.48, p = 0.002). The risk of lateral meniscal repair failure was higher in patients aged ≤ 20 years (aHR = 2.79, 95% CI 1.17-6.67, p = 0.021), when the procedure was performed by a low case volume surgeon (aHR = 1.84, 95% CI 1.08-3.13, p = 0.026) and when a transtibial technique was used to drill the femoral graft tunnel (aHR = 2.30, 95% CI 1.03-5.15, p = 0.042). CONCLUSION: The use of a hamstring tendon autograft, younger age and the presence of medial compartment cartilage injury are risk factors for medial meniscal repair failure, whereas younger age, low surgeon volume and a transtibial drilling technique are risk factors for lateral meniscal repair failure. LEVEL OF EVIDENCE: Level II.

Variable rotation of the femur does not affect outcome with patient specific alignment navigated balanced TKA.

PURPOSE: Excessive internal and external rotation of the femoral component has been associated with poor outcome with a measured-resection neutral mechanical alignment TKA. This technique assumes that every tibia is in 3° of varus so the femoral component is placed in 3° of external rotation relative to the posterior condylar axis to enable a balanced flexion gap. This is not the case as there is wide variability in the bony anatomy and soft tissue envelope of the knee so flexion imbalance may occur. A patient-specific alignment navigated balanced TKA technique was performed whereby the tibia is cut anatomically up to 3° of varus, then a ligament tensor is used to determine the optimal femoral component position for a balanced TKA. This results in variable femoral rotation. The hypothesis is that matching the femoral component rotation to the patient's anatomic tibial cut and soft tissue envelope will not affect clinical outcome METHODS: In a single surgeon series 287 consecutive varus aligned TKA's were performed using this technique with an Attune cruciate retaining fixed bearing TKA with an anatomic patella resurfacing. The angle between the posterior femoral cuts and the posterior condylar axis was collected using Brainlab software. Functional scores were collected prospectively preoperatively and at two years. The variable femoral component rotation was correlated with and compared with the functional outcome scores. RESULTS: The femoral rotation varied from 7° of internal rotation to 8°of external rotation relative to the posterior condylar axis. The mean rotation was 1.1° of external rotation. There was no significant difference in the Oxford score, WOMAC score, Forgotten Knee Score, KOOS Joint Replacement score or Patient Satisfaction in respect to the variable femoral rotation relative to the posterior condylar axis. CONCLUSION: When a more anatomic-balanced TKA technique is used variable femoral rotation will not affect clinical outcome at two years LEVEL OF EVIDENCE: II Prospective Cohort Study.

The crevice sign: a new indicator of meniscal instability in ACL reconstructions.

PURPOSE: Meniscus preservation is key in knee surgery. The newly documented crevice sign indicates instability of the medial meniscus in ACL-deficient knees. Once the sign is visualised, it is imperative that the stability of the medial meniscus is assessed and potentially treated. It was hypothesized that there would be a strong correlation between the presence of an unstable medial meniscal tear in patients with the crevice sign in ACL-deficient knees. METHODS: This was a multicenter prospective study carried out to evaluate the incidence of medial meniscal tears in patients with ACL-deficient knees and their correlation with a crevice sign. All patients (128) who had undergone ACL reconstruction between May 2020 and November 2020 were assessed arthroscopically for meniscal stability and divided in to two groups: stable (n = 84) and unstable (n = 44). Thereafter, the presence of the crevice sign was determined in each case. RESULTS: The populations were comparable in terms of sex and age (Table 1). Fisher's exact test showed a significant association between the presence of the crevice sign and the instability of the medial meniscus (p < 0.001). Descriptive statistics suggest that the presence of crevice sign was associated more frequently to MM instability (38.6% vs 1.2%; p < 0.001). The specificity of this test was 98.8% and its sensitivity was 38.6%. The positive predictive value (PPV) was 94.4% and the negative predictive value (NPV) was 75.5%. Table 1 Descriptions and comparisons of internal meniscus instability of patients by presence of crevice sign Internal meniscus instability (N = 44) Internal meniscus stability (N = 84) Total (N = 128) Gender  N 44 84 128   Male 33 (75.0) 58 (69.0) 91 (71.1)   Female 11 (25.0) 26 (31.0) 37 (28.9) Fisher's exact test (n.s.) Age (years)  N 44 84 128   Mean (ET) 28.6 (9.4) 30.1 (10.2) 29.6 (9.9)   Median (IIQ) 26.5 (22.0;34.5) 27.0 (22.5;37.0) 27.0 (22.0;36.0)   [Min-Max] [14-54] [14-52] [14-54] Wilcoxon test bilateral (n.s.) Crevice sign  N 44 84 128   Absent 27 (61.4) 83 (98.8) 110 (85.9)   Present 17 (38.6) 1 (1.2) 18 (14.1) Fisher's exact test p < 0.001 CONCLUSION: The hypothesis was confirmed since medial meniscal instability was strongly correlated with the existence of the crevice sign and showed high specificity and PPV. LEVEL OF EVIDENCE: III.

Prophylaxis for preventing venous thromboembolism in knee arthroscopy and soft tissue reconstruction: consensus statements from an international panel of experts.

PURPOSE: There is a lack of consensus regarding need for Venous Thrombo Embolism (VTE) prophylaxis following arthroscopic knee surgery and open soft tissue knee reconstruction. Clear cut guidelines like ones for trauma surgery and arthroplasty do not exist and the published literature is limited to case reports with a few society guidelines. Given this lack of consensus, we conducted a modified Delphi questionnaire of international experts to provide recommendations on this topic. METHODS: The consensus statements were generated using an anonymised 3 round modified Delphi questionnaire, sent to an international panel of 38 knee surgeons, with an 80% agreement being set as the limit for consensus. The responses were analysed using descriptive statistics with measures like mode, median and box plots. Feedback was provided to all panelists based on responses from the previous rounds to help generate the consensus. RESULTS: Six consensus statements were generated after the three rounds of Delphi. Patient factors, prolonged surgery duration and family history of thrombogenic events emerged as the main points to be taken into consideration for prophylaxis. CONCLUSION: It was established through this study, that there exists a select group of patients undergoing arthroscopic surgery that justify the usage of VTE prophylaxis. The expert responses to most of the questions in different scenarios favoured usage of VTE prophylaxis based on patient factors like advanced age, past history of VTE, smoking, oral contraceptive use etc. LEVEL OF EVIDENCE: Level V.

Patient-Specific TKA with the VELYS™ Robotic-Assisted Solution.

The VELYS™ Robotic-Assisted Solution (VRAS) (DePuy Synthes, Warsaw, Indiana) utilises new technology to accurately collect the bony anatomy and soft tissue envelope of the knee. This enables surgeons to use this information to intraoperatively plan anatomical placement of a total knee arthroplasty (TKA) with preservation of the soft tissues with the aim of restoring functional knee motion. The robotic-assisted saw delivers precise, accurate, and efficient delivery of this implantation plan. This article describes the patient-specific TKA technique which maximises the full potential of VRAS; however, all TKA techniques and alignment philosophies can be accommodated with VRAS. The first case was performed in late 2020. An early outcome study shows an improvement in knee function and pain with activity at discharge and six weeks and a neutral surgical time comparable with the author's extensive experience with patient-specific balanced TKA with navigation. Only a limited number of patients have one-year results. However, the data of this limited cohort demonstrates favourable outcome scores and high patient satisfaction.

Editorial Commentary: Increased Tibial Slope Is Associated With Anterior Cruciate Ligament Injury Risk, and Tibial Slope Increases in the Skeletally Immature, Anterior Cruciate Ligament-Deficient Knee: A Chicken or Egg Causality Dilemma?

Increased tibial slope is associated with increased risk of anterior cruciate ligament (ACL) injury in the skeletally immature. Recent studies, however, emphasize a mutual influence, as tibial slope has been shown to increase over time in the ACL-deficient skeletally immature knee. It is hypothesized that altered biomechanics with enhanced posterior force transmission in the ACL-deficient knee may influence the developing physis, leading to altered longitudinal growth and increased tibial slope. In addition to tibial slope, the meniscal geometry, including meniscal bone angle and meniscal slope, have been shown to influence the risk of ACL injury. In the skeletally immature knee, especially, the soft tissue geometry is thought to have significant impact on ACL injury risk. However, it remains unknown whether alteration of the meniscal slope may represent a causality of ACL deficiency.

Editorial Commentary: The Ratio of Tibial Slope and Meniscal Bone Angle is a Strong Predictor for Anterior Cruciate Ligament Injury: A Steep Hill and a Shallow Speed Bump are a Hazardous Combination.

The lateral tibial posterior slope (LTPS) and the lateral meniscal bone angle (MBA) are important geometrical features of the knee joint and have therefore been of interest in the setting of anterior cruciate ligament injury (ACL) and ACL reconstruction. An emerging body of evidence suggests that LTPS is an independent risk factor for primary and recurrent ACL injury. Furthermore, biomechanical and clinical evidence is emphasizing the crucial contribution of the lateral meniscus to rotatory knee stability. Thus, not surprisingly, the MBA has also been shown to be an independent risk factor regarding ACL injury. The ratio of LTPS and MBA is a relatively new idea but has shown to be highly predictive for primary and recurrent ACL injury and may be used to identify patients at high risk of ACL reconstruction failure.

Effectiveness of thicker hamstring or patella tendon grafts to reduce graft failure rate in anterior cruciate ligament reconstruction in young patients.

PURPOSE: The purpose of this study was to determine the anterior cruciate ligament reconstruction (ACLR) failure rate in young patients utilizing the New Zealand (NZ) anterior cruciate ligament (ACL) Registry. The hypothesis was that the ACLR rupture rate would be lower for thicker hamstring graft and bone patellar tendon bone (BPB) grafts in comparison to the classic hamstring technique. The ACLR failure rate was assessed according to graft type and patients' sex. METHODS: The NZ ACL registry was utilized to identify all patients aged 20 years or younger at the time of surgery who were skeletally mature and had a minimum 2-year follow-up. Graft ruptures, defined as an ACL revision, were identified according to graft type (traditional 4 strands hamstring semitendinosus and gracilis, 4 strands semitendinosus, 5-6 strands semitendinosus and gracilis, 7-8 strands semitendinosus and gracilis, bone-patella-bone graft). RESULTS: Nine-hundred and ninety-two patients were included. At a mean follow-up of 38 months, 52 cases of graft rupture were recorded, (overall failure rate: 5.2%). The failure rate was not statistically influenced by the graft diameter. Patients with a thinner graft (< 8 mm-196 patients) had a similar failure rate (6%) to patients with a thicker graft (8 mm or more-485 patients) (6.2%). There was a lower failure rate in the BPB group (3.1%) versus all hamstrings group (6%) (ns). Finally, BPB in females had a lower failure rate than all hamstring constructs together (0% versus 5.1%; p = 0.023) CONCLUSION: In a young population traditional four-strand hamstring grafts, multiple strand configurations or BPB ACLR, whatever their size (> or < 8 mm), showed no significant difference in the failure rate in the NZ ACL registry. Female patients who had an ACL reconstruction with BPB graft had a significant lower failure rate than patients who had a hamstring graft. LEVEL OF EVIDENCE: III.

ACL Study Group survey reveals the evolution of anterior cruciate ligament reconstruction graft choice over the past three decades.

PURPOSE: Anterior cruciate ligament reconstruction (ACLR) aims to restore knee function and stability, allowing patients to return to the activities they enjoy and minimize further injury to the meniscus and cartilage and their ultimate progression to osteoarthritis. This study aims to present the evolution of graft choice over the last three decades according to members of the ACL Study Group (SG). METHODS: Prior to the January 2020 ACL SG biannual meeting, a survey was administered consisting of 87 questions and 16 categories, including ACLR graft choice. A similar questionnaire has been administered prior to each meeting and survey results from the past 14 meetings (1992 through 2020, excluding 1994) are included in this work. Survey responses are reported as frequencies in percentages to quantify changes in practice over the surgery period. RESULTS: In 1992, the most frequent graft choice for primary ACLR was bone-patellar tendon-bone (BTB) autograft, at nearly 90%. Hamstring tendon (HT) autografts have increased in popularity, currently over 50%, followed by just under 40% BTB autograft. Recently, quadriceps tendon (QT) autograft has increased in popularity since 2014. CONCLUSION: Autograft (HT, BTB, QT) is an overwhelming favorite for primary ACLR over allograft. The preference for HT autograft increased over the study period relative to BTB autograft, with QT autograft gaining in popularity in recent years. Graft selection should be individualized for each patient and understanding the global trends in graft choice can help orthopaedic surgeons discuss graft options with their patients and determine the appropriate graft for each case. LEVEL OF EVIDENCE: Level V, Expert Opinion.

No difference in revision rates between anteromedial portal and transtibial drilling of the femoral graft tunnel in primary anterior cruciate ligament reconstruction: early results from the New Zealand ACL Registry.

PURPOSE: The use of an accessory anteromedial portal to drill the femoral graft tunnel in primary anterior cruciate ligament (ACL) reconstruction was introduced in the 2000s in an effort to achieve a more anatomic femoral tunnel position. However, some early studies reported an increase in revision ACL reconstruction compared to the traditional transtibial technique. The aim of this study was to analyse recent data recorded by the New Zealand ACL Registry to compare outcomes of ACL reconstruction performed using the anteromedial portal and transtibial techniques. METHODS: Analysis was performed on primary isolated single-bundle ACL reconstructions recorded between 2014 and 2018 by the New Zealand ACL Registry. Patients were categorised into two groups according to whether an anteromedial portal or transtibial technique was used to drill the femoral graft tunnel. The primary outcome was revision ACL reconstruction and was compared between both groups through univariate and multivariate survival analyses. The secondary outcomes that were analysed included subscales of the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Marx activity score. RESULTS: Six thousand one hundred and eighty-eight primary single-bundle ACL reconstructions were performed using either the anteromedial portal or transtibial drilling techniques. The mean time of follow-up was 23.3 (SD ± 14.0) months. Similar patient characteristics such as mean age (29 years, SD ± 11), sex (males = 58% versus 57%) and time to surgery (median 4 months, IQR 5) were observed between both groups. The rate of revision ACL reconstruction was 2.6% in the anteromedial portal group and 2.2% in the transtibial group (n.s.). The adjusted risk of revision ACL reconstruction was 1.07 (95% CI 0.62-1.84, n.s.). Patients in the anteromedial portal group reported improved scores for subscales of the KOOS and higher Marx activity scores at 1-year post-reconstruction. CONCLUSION: There was no difference in the risk of revision ACL reconstruction between the two femoral tunnel drilling techniques at short-term follow-up. We observed minor differences in patient-reported outcomes at 1-year follow-up favouring the anteromedial portal technique, which may not be clinically relevant. Surgeons can achieve good clinical outcomes with either drilling technique. LEVEL OF EVIDENCE: III.

Rates of revision and surgeon-reported graft rupture following ACL reconstruction: early results from the New Zealand ACL Registry.

PURPOSE: There remains a lack of consensus on the patient factors associated with graft rupture following anterior cruciate ligament (ACL) reconstruction. This study aimed to identify the rate of revision and surgeon-reported graft rupture and clarify the patient risk factors for failure. METHODS: Analysis was conducted on prospective data captured by the New Zealand ACL registry. All primary isolated ACL reconstructions recorded between April 2014 and December 2018 were reviewed to identify the rate of revision and surgeon-reported graft rupture. Univariate and multivariate survival analysis was performed to identify patient factors associated with revision and graft rupture. RESULTS: A total of 7402 primary isolated ACL reconstructions were reviewed and had a mean follow-up time of 23.1 (SD ± 13.9) months. There were 258 surgeon-reported graft ruptures (3.5%) of which 175 patients underwent subsequent revision ACL reconstruction (2.4%). Patients younger than 18 years had the highest risk of revision (adjusted HR = 7.29, p < 0.001) and graft rupture (adjusted HR = 4.26, p < 0.001) when compared to patients aged over 36 years. Male patients had a higher risk of revision (adjusted HR = 2.00, p < 0.001) and graft rupture (adjusted HR = 1.70, p < 0.001) when compared to their female counterparts. Patients who underwent ACL reconstruction within 6 months of their injury had a two times increased risk of revision compared to patients who had surgery after 12 months (adjusted HR = 2.15, p = 0.016). CONCLUSION: Younger age, male sex and a shorter injury-to-surgery time interval increased the risk of revision, while younger age and male sex increased the risk of surgeon-reported graft rupture. LEVEL OF EVIDENCE: II.

Transportal central femoral tunnel placement has a significantly higher revision rate than transtibial AM femoral tunnel placement in hamstring ACL reconstruction.

PURPOSE: It is proposed that central femoral ACL graft placement better controls rotational stability. This study evaluates the consequence of changing the femoral tunnel position from the AM position drilled transtibially to the central position drilled transportally. The difference in ACL graft failure is reported. METHODS: This prospective consecutive patient single surgeon study compares the revision rates of 1016 transtibial hamstring ACL reconstructions followed for 6-15 years with 464 transportal hamstring ACL reconstructions followed for 2-6 years. Sex, age, graft size, time to surgery, meniscal repair and meniscectomy data were evaluated as contributing factors for ACL graft failure to enable a multivariate analysis. To adjust for the variable follow-up a multivariate hazard ratio, failure per 100 graft years and Kaplan-Meier survivorship was determined. RESULTS: With transtibial ACLR 52/1016 failed (5.1%). With transportal ACLR 32/464 failed (6.9%). Significant differences between transportal and transtibial ACLR were seen for graft diameter, time to surgery, medial meniscal repair rates and meniscal tissue remaining after meniscectomy. Adjusting for these the multivariate hazard ratio was 2.3 times higher in the transportal group (p = 0.001). Central tunnel placement resulted in a significantly 3.5 times higher revision rate compared to an anteromedial tunnel placement per 100 graft years (p = 0.001). Five year survival was 980/1016 (96.5%) for transtibial versus 119/131 (90.5%) for transportal. Transportal ACLR also showed a significantly higher earlier failure rate with 20/32 (61%) of the transportal failing in the first year compared with 14/52 (27%) for transtibial. (p = 0.001.) CONCLUSION: Transportal central femoral tunnel ACLR has a higher failure rate and earlier failure than transtibial AM femoral tunnel ACLR. LEVEL OF EVIDENCE: Level II-prospective comparative study.

Does Computer Assisted Navigation Improve Functional Outcomes and Implant Survivability after Total Knee Arthroplasty?

The objective of this study was to determine whether computer assisted navigation in total knee arthroplasty (TKA) improves functional outcomes and implant survivability using data from a large national database. We analysed 9054 primary TKA procedures performed between 2006 and 2012 from the New Zealand National Joint Registry. Functional outcomes were assessed using Oxford Knee Questionnaires at six months and five years. On multivariate analysis, there was no significant difference in mean Oxford Knee Scores between the navigated and non-navigated groups at six months (39.0 vs 38.1, P=0.54) or five years (42.2 vs 42.0, P=0.76). At current follow-up, there was no difference in revision rates between navigated and non-navigated TKA (0.46 vs 0.43 revisions 100 component years, P=0.8).

Comparison of Knee Pain and Difficulty With Kneeling Between Patellar Tendon and Hamstring Tendon Autografts After Anterior Cruciate Ligament Reconstruction: A Study From the New Zealand ACL Registry.

BACKGROUND: The bone-patellar tendon-bone (BTB) autograft is associated with difficulty with kneeling after anterior cruciate ligament (ACL) reconstruction; however, it is unclear whether it results in a more painful or symptomatic knee compared with the hamstring tendon autograft. PURPOSE: To identify the rate and risk factors for knee pain and difficulty with kneeling after ACL reconstruction. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Primary ACL reconstruction procedures prospectively recorded in the New Zealand ACL Registry from April 2014 to May 2021 were analyzed. The Knee injury and Osteoarthritis Outcome Score (KOOS) was used to identify patients reporting consequential knee pain (CKP), defined as a KOOS Pain subscore of ≤72 points, and severe kneeling difficulty (SKD), defined as a self-report of "severe" or "extreme" difficulty with kneeling. Absolute values of the KOOS Pain and Symptoms subscales were also compared. RESULTS: A total of 10,999 patients were analyzed. At 2-year follow-up, 9.3% (420/4492) reported CKP, and 12.0% (537/4471) reported SKD. The most important predictor of CKP at 2-year follow-up was having significant pain before surgery (adjusted odds ratio, 4.10; P < .001). The most important predictor of SKD at 2-year follow-up was the use of a BTB autograft rather than a hamstring tendon autograft (21.3% vs 9.4%, respectively; adjusted odds ratio, 3.12; P < .001). There was no difference between the BTB and hamstring tendon grafts in terms of CKP (9.9% vs 9.2%, respectively; P = .494) or in absolute values of the KOOS Pain (mean, 88.7 vs 89.0, respectively; P = .37) and KOOS Symptoms (mean, 82.5 vs 82.1, respectively; P = .49) subscales. CONCLUSION: At 2-year follow-up after primary ACL reconstruction, 9.3% of patients reported CKP, and 12.0% reported SKD. The BTB autograft was associated with difficulty with kneeling, but it did not result in a more painful or symptomatic knee compared with the hamstring tendon autograft.

Digital TKA Alignment Training with a New Digital Simulation Tool (Knee-CAT) Improves Process Quality, Efficiency, and Confidence.

Individual alignment techniques have been introduced to restore patients' unique anatomical variations during total knee arthroplasty. The transition from conventional mechanical alignment to individualised approaches, with the assistance of computer and/or robotic technologies, is challenging. The objective of this study was to develop a digital training platform with real patient data to educate and simulate various modern alignment philosophies. The aim was to evaluate the training effect of the tool by measuring the process quality and efficiency, as well as the post-training surgeon's confidence with new alignment philosophies. Based on 1000 data sets, a web-based interactive TKA computer navigation simulator (Knee-CAT) was developed. Quantitative decisions on bone cuts were linked to the extension and flexion gap values. Eleven different alignment workflows were introduced. A fully automatic evaluation system for each workflow, with a comparison function for all workflows, was implemented to increase the learning effect. The results of 40 surgeons with different experience levels using the platform were assessed. Initial data were analysed regarding process quality and efficiency and compared after two training courses. Process quality measured by the percentage of correct decisions was increased by the two training courses from 45% to 87.5%. The main reasons for failure were wrong decisions on the joint line, tibia slope, femoral rotation, and gap balancing. Efficiency was obtained with a reduction in time spent per exercise from 4 min 28 s to 2 min 35 s (42%) after the training courses. All volunteers rated the training tool as helpful or extremely helpful for learning new alignment philosophies. Separating the learning experience from OR performance was mentioned as one of the main advantages. A novel digital simulation tool for the case-based learning of various alignment philosophies in TKA surgery was developed and introduced. The simulation tool, together with the training courses, improved surgeon confidence and their ability to learn new alignment techniques in a stress-free out-of-theatre environment and to become more time efficient in making correct alignment decisions.

Suspensory Versus Interference Tibial Fixation of Hamstring Tendon Autografts in Anterior Cruciate Ligament Reconstruction: Results From the New Zealand ACL Registry.

BACKGROUND: The hamstring tendon is frequently used to reconstruct the anterior cruciate ligament (ACL), but there is a lack of consensus on the optimal method of fixation. Registry studies have shown that the type of femoral fixation device can influence the risk of revision ACL reconstruction (ACLR), but it is unclear whether the type of tibial fixation has an effect. In New Zealand, over 95% of hamstring tendon grafts are fixed with an adjustable loop suspensory device on the femoral side, with variable usage between suspensory and interference devices, with or without a sheath, on the tibial side. PURPOSE: To investigate the association between the type of tibial fixation device and the risk of revision ACLR. STUDY DESIGN: Cohort Study; Level of evidence, 2. METHODS: Prospective data recorded in the New Zealand ACL Registry were analyzed. Only primary ACLRs performed with a hamstring tendon autograft fixed with a suspensory device on the femoral side were included. A Cox regression survival analysis with adjustment for patient factors was performed to analyze the effects of the type of tibial fixation device, the number of graft strands, and graft diameter on the risk of revision. RESULTS: A total of 6145 primary ACLRs performed between 2014 and 2019 were analyzed. A total of 59.6% of hamstring tendon autografts were fixed with a suspensory device on the tibial side (n = 3662), 17.6% with an interference screw with a sheath (n = 1079), and 22.8% with an interference screw without a sheath (n = 1404). When compared with suspensory devices, a higher revision risk was observed when using an interference screw with a sheath (adjusted hazard ratio [HR], 2.05; P = .009) and without a sheath (adjusted HR, 1.81; P = .044). The number of graft strands and a graft diameter of ≥8 mm were associated with the rate of revision on the univariate analysis; however, after adjusting for confounding variables on the multivariate analysis, they did not significantly influence the risk of revision. CONCLUSION: In this study of hamstring tendon autografts fixed with an adjustable loop suspensory device on the femoral side during primary ACLR, the use of an interference screw, with or without a sheath, on the tibial side resulted in a higher revision rate when compared with a suspensory device.

Higher Rate of Return to Preinjury Activity Levels After Anterior Cruciate Ligament Reconstruction With a Bone-Patellar Tendon-Bone Versus Hamstring Tendon Autograft in High-Activity Patients: Results From the New Zealand ACL Registry.

BACKGROUND: In primary anterior cruciate ligament (ACL) reconstruction, a bone-patellar tendon-bone (BTB) autograft is associated with lower ipsilateral failure rates. BTB autografts are associated with a higher rate of contralateral ACL injuries, which some clinicians view as a marker of success of the BTB autograft. However, there is a lack of evidence on whether BTB autografts improve the rate of return to activity and sport. PURPOSE: To compare the rate of return to preinjury activity levels in high-activity patients after ACL reconstruction with BTB autograft or hamstring tendon autograft. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: In a high-activity cohort of patients recorded between 2014 and 2018 in the New Zealand ACL Registry, prospectively collected data on preinjury and postoperative Marx activity scores were analyzed. The proportion of patients who returned to their preinjury activity levels at 1- and 2-year follow-up was compared between graft types. RESULTS: Overall, 11.3% (208/1844) of patients returned to their preinjury activity levels at 1-year follow-up, and 15.5% (184/1190) returned at 2-year follow-up. At 1-year follow-up, 17.2% of patients with a BTB autograft returned to their preinjury activity levels compared with 9.3% of patients with a hamstring tendon autograft (adjusted odds ratio, 1.59 [95% CI, 1.16-2.17]; P = .004). At 2-year follow-up, 23.3% of patients with a BTB autograft had returned to their preinjury activity levels compared with 13.3% of patients with a hamstring tendon autograft (adjusted odds ratio, 1.63 [95% CI, 1.14-2.34]; P = .008). Male sex and younger age were associated with a higher rate of return to activity at both follow-up time points. CONCLUSION: The use of BTB autografts increased the odds of returning to preinjury activity levels at early follow-up. A higher rate of return to activity is a possible explanation for the higher rate of contralateral ACL injuries with the use of BTB autografts.

Comparison of Existing and New Total Knee Arthroplasty Implant Systems From the Same Manufacturer: A Prospective, Multicenter Study.

INTRODUCTION: This study evaluated total knee arthroplasty (TKA) outcomes for an Existing-TKA versus New-TKA from the same manufacturer. METHODS: TKA outcomes for 752 with Existing-TKA versus 1129 subjects with New-TKA were followed through 2 years using patient-reported outcome measures (PROMs). Responders were assessed per Outcome Measures in Rheumatology-Osteoarthritis Research Society International criteria. Kaplan-Meier implant survivorship was estimated. Radiographs had an independent radiographic review. RESULTS: Two-year follow-up was 84.6% (636/752) for Existing-TKA and 82.5% (931/1129) for New-TKA. Two-year PROMs mean outcomes for New-TKA versus Existing-TKA at 2 years were: Knee Injury and Osteoarthritis Outcome Score (ADL: 89.0 versus 86.8, P = 0.005; pain: 88.9 versus 87.1, P = 0.019; symptoms: 84.1 versus 82.2, P = 0.017; Sport/Rec: 63.9 versus 58.8, P = 0.001; and QOL: 77.0 versus 73.5, P = 0.003), Patient's Knee Implant Performance (overall: 76.5 versus 73.5, P = 0.003; confidence: 8.4 versus 8.1, P = 0.004; stability: 8.6 versus 8.3, P = 0.006; satisfaction: 8.3 versus 8.1, P = 0.042; and modifying activities: 6.6 versus 6.4, P = 0.334), Oxford Knee Score (41.9 versus 41.1, P = 0.027), and EQ5D-3L (0.88 versus 0.88, P = 0.737). Two-year responder rates using WOMAC were 93.9% versus 90.6% (P = 0.018) for New-TKA versus Existing-TKA. Independent radiographic review showed that tibial and femoral radiolucencies ≥2 mm were similar (P ≥ 0.05) or favored New-TKA. Implant survivorship was similar between groups (log-rank P = 0.9994). DISCUSSION: New-TKA versus Existing-TKA demonstrated slightly better PROMs with similar radiographic and implant survivorship outcomes.