Bi-cruciate retaining total knee arthroplasty is here to stay: A consecutive series transitioning from manual instrumentation to enabling technologies.

BACKGROUND: Bicruciate-retaining (BCR) total knee arthroplasty (TKA) has seen renewed interest due to the potential for more natural knee kinematics with anterior cruciate ligament (ACL) retention. OBJECTIVE: The present study attempts to determine differences in the 2-year survivorship and patient-reported outcomes between two surgical strategies (traditional instrumentation versus robotics) applied to the extensive use of a modern, 2nd generation BCR TKA design. METHODS: We performed a retrospective study with prospectively collected data of 113 patients who underwent primary TKA between 2018 and 2020 using a 2nd generation BCR TKA implant. Patient demographics, PROMS, and intra/post-operative complications were collected. Patients were also evaluated according to the use or not of robotics. A Kaplan-Meier analysis was used to evaluate revision-free survival at follow up. RESULTS: 102 patients were enrolled: 90 received traditional surgery and 12 robotic-assisted surgery. The mean age was 68 years (SD 7.76) with an average BMI of 29.6 kg/m2 (SD 3.56). The mean follow up (FU) was 32.4 ± 6.2 months (range 24-45 months). Survivorship at 2 years was 98% (95% CI: 92.4-99.5). Revisions/reoperations were performed for anterior cruciate ligament (ACL) tear (1/4), pain (1/4), arthrofibrosis (1/4) and acute periprosthetic joint infection (PJI) (1/4). At final FU, 92 patients (90.2%) considered themselves satisfied, showing a mean OKS of 40.6 (SD 5.1) and a mean FKS of 76.7 (SD 11.8). No differences in the outcome were found between traditional and robotic-assisted procedures. CONCLUSION: The modern BCR design evaluated in this study achieved excellent results in terms of implant survivorship, low rate of reoperation and clinical results, independently from the use of enabling technologies.

Unexpected Positive Cultures in Hip and Knee Periprosthetic Fractures.

BACKGROUND: The purpose of this study was to determine the prevalence of unexpected positive cultures noted at the time of revision surgery for periprosthetic fracture (PPF) after total hip or knee arthroplasty. Moreover, we evaluated whether this finding should be considered clinically significant and what type of treatment, if any, was required. METHODS: This was a single-center retrospective review of 270 patients undergoing surgery for PPFs from December 2010 to December 2021. Exclusion criteria included: open fractures; history of infection at fractured joint; non-operatively treated patients; and intraoperative fractures. The primary end point was the prevalence of unexpected positive cultures noted at the time of revision surgery. This was defined as one or more positive cultures in a PPF that the surgeon had preoperatively classified as aseptic according to the 2018 International Consensus Meeting. Data collection included patient demographics, medical histories, preoperative investigations, postoperative microbiology, and treatment. RESULTS: During the study period, 159 patients were admitted with PPFs of the hip and 61 with PPFs of the knee. The mean age was 70 years (range, 32 to 93 years). Unexpected positive cultures were diagnosed postoperatively in 15 patients (6.8%; 10 hips, 5 knees). The most prevalent organism was Staphylococcus epidermidis (35.0%). Of those 15 patients, 6 required a surgical revision for infection. None of the patient-related risk factors were found to be associated with an increased risk of unexpected positive cultures. The comparison between infected and noninfected patients showed a significant association between preoperative C-reactive protein >10 mg/mL (P = .04), loose implant (P = .07), and infection. CONCLUSIONS: The prevalence of unexpected positive cultures was 6.8% in our study cohort. Although surgical treatment may be required, the majority of patients seem to require no treatment. Larger series are required to investigate the clinical importance of this rare finding. LEVEL OF EVIDENCE: III.

A novel geometrical planning method to restore knee joint obliquity in double-level osteotomies.

PURPOSE: Precise preoperative planning is mandatory when a double-level osteotomy (DLO) is required to correct a severe knee deformity. Literature does not report a validated planning method regarding DLO that could be performed directly on digital radiographs using simple measurement tools. This study aims to validate a novel DLO planning method called New Mikulicz-Joint Line (NM-JL) based on essential measurement tools, in which the correction angles are induced by the predicted post-operative joint line obliquity (JLO). METHODS: Twenty-three patients who satisfied the inclusion criteria were enrolled. NM-JL planning method was performed using basic measurement tools to detect corrective angles and gaps. The correction was then simulated using a Virtual Segmentation Software method to obtain the osteotomy fragments. Both planning procedures were performed independently and later repeated by two orthopaedic surgeons to assess the inter and intra-observer reliability. RESULTS: The intraclass correlation coefficient (ICC) regarding corrective angles and gaps showed a significant positive correlation between the values determined using the two procedures by both raters (p < 0.05). Pearson's correlation analysis revealed a significant correlation between the measured results of the two planning methods. (p < 0.05). Finally, the Bland-Altman analysis showed an excellent agreement (p < 0.05) for all measurements performed. CONCLUSIONS: The NM-JL method showed high values of intra and inter-rater reliability. The procedure is built up starting from the predicted value of post-operative joint line obliquity, allowing to maintain this parameter fixed. Other advantages include the quickness, adaptability, and possibility to be performed on any Digital Imaging and Communication in Medicine (DICOM) viewer. LEVEL OF EVIDENCE: Level IV.

Characterizing recurrent infections after one-stage revision for periprosthetic joint infection of the knee: a systematic review of the literature.

BACKGROUND: Periprosthetic joint infection (PJI) of the knee represents a severe complication after 1.5% to 2% of primary total knee replacement. Although two-stage revision was considered the gold-standard treatment for PJI of the knee, in the last decades, more studies reported the outcomes of one-stage revisions. This systematic review aims to assess reinfection rate, infection-free survival after reoperation for recurrent infection, and the microorganisms involved in both primary and recurrent infection. MATERIAL AND METHODS: A systematic review of all studies reporting the outcome of one-stage revision for PJI of the knee up to September 2022, according to PRISMA criteria and AMSTAR2 guidelines, was performed. Patient demographics, clinical, surgical, and postoperative data were recorded. PROSPERO ID: CRD42022362767. RESULTS: Eighteen studies with a total of 881 one-stage revisions for PJI of the knee were analyzed. A reinfection rate of 12.2% after an average follow-up of 57.6 months was reported. The most frequent causative microorganism were gram-positive bacteria (71.1%), gram-negative bacteria (7.1%), and polymicrobial infections (8%). The average postoperative knee society score was 81.5, and the average postoperative knee function score was 74.2. The infection-free survival after treatment for recurrent infection was 92.1%. The causative microorganisms at reinfections differed significantly from the primary infection (gram-positive 44.4%, gram-negative 11.1%). CONCLUSION: Patients who underwent a one-stage revision for PJI of the knee showed a reinfection rate lower or comparable to other surgical treatments as two-stage or DAIR (debridement, antibiotics, and implant retention). Reoperation for reinfection demonstrates a lower success compared to one-stage revision. Moreover, microbiology differs between primary infection and recurrent infection. Level of evidence Level IV.

Anterolateral complex of the knee: State of the art.

Rotatory instability of the knee represents the main reason for failure and poor clinical outcomes regarding anterior cruciate ligament (ACL) reconstruction techniques. It is now clear that the anterolateral complex (ALC) of the knee possesses a fundamental role, in association with the ACL, in controlling internal rotation. Over the past decade, ever since the anterolateral ligament has been identified and described as a distinct structure, there has been a renewed interest in the scientific community about the whole ALC: Lateral extra-articular tenodesis have made a comeback in association with ACL reconstructions to improve functional outcomes, reducing the risks of graft failure and associated injuries. Modern ACL reconstruction surgery must therefore investigate residual instability and proceed, when necessary, to extra-articular techniques, whether functional tenodesis or anatomical reconstruction.This review aims to investigate the latest anatomical and histological descriptions, and the role in rotational control and knee biomechanics of the ALC and its components. The diagnostic tools for its identification, different reconstruction techniques, and possible surgical indications are described.. In addition, clinical and functional results available in the literature are reported.

Tibial condylar valgus osteotomy for the treatment of intra-articular varus deformity of the knee.

The increasing incidence and distribution of primary and post-traumatic knee osteoarthritis (OA) in the young, active population has renewed interest in joint-preserving procedures. High tibial osteotomy (HTO) represents the most common treatment for medial knee OA associated with varus tibial deformity. However, deformities may also be related to intra-articular defects that an extra-articular procedure could not correct. The tibial condylar valgus osteotomy (TCVO) represents an intra-articular surgical technique for treating advanced medial knee OA with lateral joint subluxation. Currently, only a few papers with small samples and limited follow-up report the use of TCVO for the treatment of intra-articular deformities. Indications and operative techniques are various and not standardized. After an extensive search of PubMed, Scopus and Cochrane library, the main purpose of this paper is to summarize and discuss the indications, surgical techniques, and outcomes of intra-articular osteotomies while also reporting the preoperative planning and surgical procedure performed at our institution. These characteristics allow earlier weight-bearing and faster complete recovery. TCVO is an effective procedure to correct lower limbs' intra-articular defects from degenerative conditions developmental and post-traumatic deformities. This surgical technique, working at the intra-articular level, leads to some benefits related to restoring joint congruence and stability by realigning the axis of the lower limb and reducing the lateral joint subluxation. Moreover, the improved valgisation and lateralization of the mechanical axis and the limitation of the osteotomy to the medial condyle led to a better load distribution to the not osteotomy-involved compartment.

Bicruciate-retaining total knee arthroplasty: What's new?

Primary total knee arthroplasty (TKA) is a widespread procedure to address end stage osteoarthritis with good results, clinical outcomes, and long-term survivorship. Although it is frequently performed in elderly, an increased demand in young and active people is expected in the next years. However, a considerable dissatisfaction rate has been reported by highly demanding patients due to the intrinsic limitations provided by the TKA. Bicruciate-retaining (BCR) TKA was developed to mimic knee biomechanics, through anterior cruciate ligament preservation. First-generation BCR TKA has not gained popularity due to its being a challenging technique and having poor survival outcomes. Thanks to implant design improvement and surgeon-friendly instrumentation, second-generation BCR TKA has seen renewed interest. This review will focus on surgical indications, kinematical basis, clinical results and latest developments of second-generation BCR TKA.

Kinetic Sensors for Ligament Balance and Kinematic Evaluation in Anatomic Bi-Cruciate Stabilized Total Knee Arthroplasty.

Sensor technology was introduced to intraoperatively analyse the differential pressure between the medial and lateral compartments of the knee during primary TKA using a sensor to assess if further balancing procedures are needed to achieve a "balanced" knee. The prognostic role of epidemiological and radiological parameters was also analysed. A consecutive series of 21 patients with primary knee osteoarthritis were enrolled and programmed for TKA in our unit between 1 September 2020 and 31 March 2021. The VERASENSE Knee System (OrthoSensor Inc., Dania Beach, FL, USA) has been proposed as an instrument that quantifies the differential pressure between the compartments of the knee intraoperatively throughout the full range of motion during primary TKA, designed with a J-curve anatomical femoral design and a PS "medially congruent" polyethylene insert. Thirteen patients (61.90%) showed a "balanced" knee, and eight patients (38.10%) showed an intra-operative "unbalanced" knee and required additional procedures. A total of 13 additional balancing procedures were performed. At the end of surgical knee procedures, a quantitatively balanced knee was obtained in all patients. In addition, a correlation was found between the compartment pressure of phase I and phase II at 10° of flexion and higher absolute pressures were found in the medial compartment than in the lateral compartment in each ROM degree investigated. Moreover, those pressure values showed a trend to decrease with the increase in flexion degrees in both compartments. The "Kinetic Tracking" function displays the knee's dynamic motion through the full ROM to evaluate joint kinetics. The obtained kinetic traces reproduced the knee's medial pivot and femoral rollback, mimicking natural knee biomechanics. Moreover, we reported a statistically significant correlation between the need for soft tissue or bone resection rebalancing and severity of the initial coronal deformity (>10°) and a preoperative JLCA value >2°. The use of quantitative sensor-guided pressure evaluation during TKA leads to a more reproducible "balanced" knee. The surgeon, evaluating radiological parameters before surgery, may anticipate difficulties in knee balance and require those devices to achieve the desired result objectively.

Outcomes at 20 years after meniscectomy in young patients.

AIM: To define arthroscopic meniscectomy (AM) outcomes in young patients at 20 years follow up in terms of predictors of poor clinical results, rate and timing of conversion to total knee replacement (TKR). METHODS: The following data were collected for 225 patients aged between 18 and 50 years with meniscal tear (MT) who underwent AM: age at surgery, gender, injured meniscus, knee alignment, associated lesions, amount of meniscal resection. At 20 years follow up, rate and timing of TKR conversion and clinical outcomes with Knee injury and Osteoarthritis Outcome Score (KOOS) score were reviewed. RESULTS: Ten patients (4.4%) required TKR in the follow up period. The mean time from AM to TKR was 7.0 years (standard deviation 3.87). Age between 40 and 50 years at AM (P < 0.01), malalignment (P < 0.01), lateral meniscectomy (any size, P = 0.01), advanced chondral lesion (Outerbridge > 2, P < 0.01) and total meniscectomy (P < 0.01) were significantly related to subsequent TKR. Negative predicting factors to obtaining equal or superior to age/sex-adjusted KOOS score were age between 40 and 50 years old at time of AM (P < 0.01), female sex (P < 0.01), malalignment (P = 0.04), and advanced chondral lesion (Outerbridge > 2, P = 0.02). CONCLUSIONS: Twenty years conversion rate to TKR after AM for MT is 4.4% and TKR was performed after a mean time of 7 years. Significant association between TKR surgery and advanced chondral lesion (Outerbridge > 2), total meniscectomy, lateral meniscectomy, age at surgery between 40 and 50 years old, and malalignment were found. Age between 40 and 50 years at time of AM, female, malalignment, advanced chondral lesion were all factors significantly related to poor clinical results.

All-inside technique in ACL reconstruction: mid-term clinical outcomes and comparison with AM technique (Hamstrings and BpTB grafts).

PURPOSE: The aim of this study was to define the subjective and objective clinical results of all-inside surgical technique at a medium-term follow-up and to compare these results with those obtained from antero-medial (AM) ACL reconstruction technique using hamstrings (HS) or bone-patellar tendon-bone (BpTB) grafts to detect eventual superiority of one technique to another. METHODS: A retrospective analysis of routinely collected data was conducted. Inclusion criteria were ACL reconstruction through all-inside technique or AM technique with HS or BpTB performed between January 2015 and May 2018; age between 15 and 30 year old; minimum 24 months' available follow-up. Exclusion criteria were contralateral ACL reconstruction; need for any other associated procedures during surgery. Clinical outcomes were assessed with KOOS, Lysholm, Tegner scores and KT-1000 device. RESULTS: According to the selection criteria, 157 patients were enrolled and divided subsequently into 3 groups: all-inside (51 patients), AM-HS (53 patients) and AM-BpTB (53 patients). A significant postoperative improvement of each score in all groups was detected. The mean KT-1000 was 3.1 ± 1.0 mm in all-inside group, while 3.3 ± 1.4 mm and 2.5 ± 0.4 mm in AM-HS and AM-BpTB groups, respectively. Comparing the results obtained, no statistically significant difference was found between the three techniques (p = 0.27). Statistically significant differences were highlighted in surgical duration: all-inside method was the longest (117'), followed by AM-BpTB surgery (101') and AM-HS technique (87'). CONCLUSIONS: The all-inside technique showed good postoperative results at medium-term follow-up. It could be a valuable solution for ACL reconstruction, especially in young patients due to its less invasiveness, despite surgical skills and time needed. LEVELS OF EVIDENCE: Level IV.

Outcomes at 20 Years After Meniscectomy in Patients Aged 50 to 70 Years.

PURPOSE: To report the outcomes of arthroscopic meniscectomy (AM) at 20 years of follow-up through timing/rate of conversion to total knee replacement (TKR) and Knee Injury and Osteoarthritis Outcome Score (KOOS), focusing on detection of specific predictor variables for these outcomes, in patients 50 to 70 years old. METHODS: We performed a retrospective study of 289 patients, ages at surgery 50 to 70 years, with diagnosis of degenerative meniscal tear who underwent arthroscopic meniscectomy. We collected the following baseline data: age, sex, injured meniscus (medial, lateral, or both), knee alignment, osteoarthritis (OA), associated lesion identified during arthroscopy, and associated procedure performed during arthroscopy. At 20 years of follow-up, we collected rate and timing of TKR conversion, and we evaluated clinical outcomes with KOOS. RESULTS: Female sex (P < .01), older age (P < .01), lateral meniscectomy (P = .02), malalignment (P = .03), and advanced chondral lesion (P < .01) were found to be significantly related to subsequent TKR. No significant correlation was found between amount of resection and subsequent TKR (P = .26). Negative predictor factors to obtain equal or superior to age- and sex-adjusted KOOS scores were age 60 to 70 years at time of AM (P = .03) and lateral meniscectomy (P = .02). CONCLUSIONS: We report a 15.7% conversion rate at 20 years from AM to TKR and a mean time between surgeries of 7 years. Subsequent TKR in the 20 years after AM for degenerative meniscus tears were significantly associated with preoperative OA and chondral lesion (Kellgren Lawrence 2; Outerbridge >2), lateral meniscectomy, age at surgery, female sex, and malalignment. Furthermore, age >60 years, lateral meniscectomy, and concurrent anterior cruciate ligament reconstruction were negative predictors for poor clinical outcomes at 20 years. Therefore, if patients present with negative predictor factors, the AM should not be proposed as second-line treatment, and nonoperative management should be continued until TKR is unavoidable. LEVEL OF EVIDENCE: IV, case series.

Combining kinematic alignment and medial stabilized design in total knee arthroplasty: Basic rationale and preliminary clinical evidences.

Objective: kinematic alignment technique has been recently described as a new surgical procedure able to restore the patient specific physiological knee alignment; furthermore, new prosthesis, as medial stabilized (MS) third generation TKA, were designed to better reproduce the anatomical shape of the knee. In this prospective study, the authors evaluated early clinical improvement and radiological outcomes of patients having pre-operative small coronal limb deformity underwent TKA using a surgical technique combining a "restricted kinematic alignment" with medial stabilized polyethylene insert. METHODS: Fifteen consecutive patients (8 female and 7 male) scheduled for a total knee replacement have been enrolled for this study and treated using a modern third generation knee implant with a medial congruent tibial polyethylene. Clinical improvements have been assessed pre-operatively and at 6 and 12 months Follow up (FU) using the Oxford knee Score (OKS)( Ishikawa et al., Jun. 2015) 12 the Knee Society Score (KSS)( Pinskerova and et al., Aug. 2004) 13 and Forgotten Joint Score (FJS) as patient reported outcomes measurement system (PROMs). A radiological evaluation was made by a single physician at 6 months. RESULTS: Average improvement in OKS was from 20.2 (SD 5.5) pre-operatively to 41.3 (SD 2.1) at the final FU. KSS pain/motion improved with a mean score from 40.1 (SD 4.0) pre-op to 89.1 (SD 6.3) while KSS function improved with an average score from 51.0 (SD 6.2) pre-op to 81.8 (SD 8.4) showing good to excellent results in all the knee treated. The mean FJS at 6 months follow up was 75.1 (SD 4.2) improving to 79.3 (SD 3.3) at one year FU. Post-operative XR showing an average varus Hip-Knee-Ankle (HKA) angle of 178.8° (range from 176° to 182°, SD 2,3°); We found no statistically significant difference between pre-operative and post-operative HKA (p < 0,05). CONCLUSION: The current authors assumed appropriate to combine a modern TKA implant designed replicating the anatomical shape of the native knee with a surgical technique able to better reproduce the physiological, patient specific, knee biomechanics. Our findings suggest that combining MS implant with KA technique may results in better short-term functional results, helping the patient to "forget" their replaced joint and restoring their pre-arthritic quality of life.