Aims

Valgus subsidence of uncemented tibial components following medial unicompartmental knee arthroplasty (UKA) poses a challenge in the early postoperative phase, necessitating a comprehensive understanding of its prevalence, risk factors, and impact on patient outcomes.

The February 2025 Knee Roundup³⁶⁰ looks at: Once-weekly semaglutide in patients with obesity and knee osteoarthritis; How many patients should have a unicompartmental knee arthroplasty?; Staged revision of the infected knee arthroplasty and endoprosthesis; The metal allergy argument and knee arthroplasty; Is kinematic alignment all it’s cracked up to be?; Is bone-patella-bone the gold standard for revision?; Blood flow restriction and the dissatisfied knee arthroplasty.

Cite this article: Bone Jt Open 2024;5(12):1120–1122.

Aims

Unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) have both been shown to be effective treatments for osteoarthritis (OA) of the knee. Many studies have compared the outcomes of the two treatments, but less so with the use of robotics, or individualized TKA alignment techniques. Functional alignment (FA) is a novel technique for performing a TKA and shares many principles with UKA. Our aim was to compare outcomes from a case-matched series of robotic-assisted UKAs and robotic-assisted TKAs performed using FA.

Introduction. Instability in ACL deficient knees can lead to medial compartment osteoarthritis. The risk of developing significant OA is 5x higher in knees with ACL deficiency. In associated Varus, there is quicker progression of the medial OA along with a varus thrust exerting strain on the ACL graft. The simultaneous valgus HTO and ACL reconstruction decompresses the medial tibiofemoral joint, corrects the mechanical-axis and reduces strain on the graft. Outcomes for this simultaneous procedure are still unclear in literature and we attempt evaluating its functional outcome. Methods. This Panel study was performed using data from 2019 to 2022 on 21 patients who had ACL insufficiency with Varus or medial OA and underwent a simultaneous Opening-wedge HTO with Arthroscopic ACL reconstruction. The mean follow-up was 2 years. The patients were evaluated with IKDC and Lysholm scores, Lachman test and ROM pre and post-operatively. The HKA was compared pre and post-operatively and the complications were evaluated. The progression of OA was evaluated with serial radiographs post-operatively. Results. There was a significant improvement in lifestyle and knee joint function post-operatively. The mechanical femorotibial angle was corrected from an average of 8.2° Varus to 0.8° Valgus. There was a significant improvement in IKDC and Lysholm scoring (IKDC score improved to 86.20 from 34.48 and the Lysholm score improved to 89 points from 37 points). There was significant improvement in the laxity which was evaluated by Lachman test. One patient had a clinical progression of medial-OA. No patients had non-union, graft or implant failure. Conclusion. Single stage HTO and ACL Reconstruction in patients with medial OA or Varus with ACL insufficiency is an option showing a satisfactory functional and radiological outcome along with activity scores

Aims

Extracellular matrix (ECM) is a critical determinant of tissue mechanobiology, yet remains poorly characterized in joint tissues beyond cartilage in osteoarthritis (OA). This review aimed to define the composition and architecture of non-cartilage soft joint tissue structural ECM in human OA, and to compare the changes observed in humans with those seen in animal models of the disease.

Introduction. Understanding knee joint biomechanics is crucial, but studying Anterior cruciate ligament (ACL) biomechanics in human adolescents is challenging due to limited availability cadaveric specimens. This study aims to validate the adolescent porcine stifle joint as a model for ACL studies by examining the ACL's behavior under axial and torsion loads and assessing its deformation rate, stiffness, and load-to-failure. Methods. Human knee load during high-intensity sports can reach 5-6 times body weight. Based on these benchmarks, the study applied a force equivalent to 5-times body weight of juvenile porcine samples (90 pounds), estimating a force of 520N. Experiments involved 30 fresh porcine stifle joints (Yorkshire breed, Avg 90 lbs, 2-4 months old) stored at -22°C, then thawed and prepared. Joints were divided into three groups: control (load-to-failure test), axially loaded, and 30-degree torsion loaded. Using a servo-hydraulic material testing machine, the tibia's longitudinal axis was aligned with the load sensor, and specimens underwent unidirectional tensile loading at 1 mm/sec until rupture. Data on load and displacement were captured at 100 Hz. Results. One-way ANOVA showed statistically significant differences in maximum failure force among loading conditions (p = 0.0039). Post hoc analysis indicated significant differences between the control and 500N (non-twisted) groups (p = 0.014) and between the control and 500N (twisted) groups (p = 0.003). However, no significant difference was found between 500N (non-twisted) and 500N (twisted) groups (p = 0.2645). Two samples broke from the distal femur growth plates, indicating potential growth plate vulnerability in adolescent porcines. Conclusions. The study validates the adolescent porcine stifle joint as a suitable model for ACL biomechanical research, demonstrating that torsional loads are as damaging to the ACL's integrity as equivalent axial loads. It also highlights the potential vulnerability of growth plates in younger populations, reflected in the porcine model

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The aim of this study was to compare patient-reported outcomes (PROMs) following isolated anterior cruciate ligament reconstruction (ACLR), with those following ACLR and concomitant meniscal resection or repair.

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This study examined windswept deformity (WSD) of the knee, comparing prevalence and contributing factors in healthy and osteoarthritic (OA) cohorts.

Patellar dislocation is a common presentation with a clear management pathway. Sometimes, however, what a patient experiences as the patella dislocating may, in fact, be ACL insufficiency. We reviewed case notes and imaging of 315 consecutive ACL reconstructions, collecting data on the date and mechanism of injury, time to MRI, and reconstruction. We noted cases initially diagnosed as patellar dislocation. 25 of 315 (7.9%) patients were initially diagnosed with a patellar dislocation. Subsequently, however, MRI scans revealed no evidence of patellar dislocation and instead showed ACL rupture with pathognomonic pivot-shift bony oedema. The false patella dislocation group were 32% female and had an average age of 25; the rest of the group average age was 27.1 and there were a lower proportion of females; 21%. The false patella instability patients had a median waiting time of 412 days from injury to operation (range: 70-2445 days), compared to 392 days (range: 9 – 4212 days) for rest of the patients. 5 of the remaining 290 had MRIs showing patella oedema with medial patello-femoral ligament injury in addition to their ACL rupture. From our literature search this is a new finding which shows that ACL rupture can present with symptoms suggestive of patellar dislocation. These findings raise the risk that there are a group of people who have been diagnosed with patellar instability who instead have ACL insufficiency and so are at risk of meniscal and chondral damage. Further research should analyse those diagnosed with patellar instability to quantify missed ACL injuries

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Patient dissatisfaction following primary total knee arthroplasty (TKA) with manual jig-based instruments has been reported to be as high as 30%. Robotic-assisted total knee arthroplasty (RA-TKA) has been increasingly used in an effort to improve patient outcomes, however there is a paucity of literature examining patient satisfaction after RA-TKA. This study aims to identify the incidence of patients who were not satisfied following RA-TKA and to determine factors associated with higher levels of dissatisfaction.

Aims

Sagittal plane imbalance (SPI), or asymmetry between extension and flexion gaps, is an important issue in total knee arthroplasty (TKA). The purpose of this study was to compare SPI between kinematic alignment (KA), mechanical alignment (MA), and functional alignment (FA) strategies.

Meniscal tears commonly co-occur with ACL tears, and many studies address their side, pattern, and distribution. Few studies assess the patient's short-term functional outcome concerning tear radial and circumferential distribution based on the Cooper et al. classification. Meniscal tears require primary adequate treatment to restore knee function. Our hypothesis is to preserve the meniscal rim as much as possible to maintain the load-bearing capacity of the menisci after meniscectomy.

The purpose of this study is to document the location and type of meniscal tears that accompany anterior cruciate ligament (ACL) tears and their effect on patient functional outcomes following arthroscopic ACL reconstruction and meniscectomy.

This prospective cross-sectional observational study was conducted at AL-BASRA Teaching Hospital in Iraq between July 2018 and January 2020 among patients with combined ipsilateral ACL injury and meniscal tears. A total of 28 active young male patients, aged 18 to 42 years, were included. All patients were subjected to our questionnaire, full history, systemic and regional examination, laboratory investigations, imaging studies, preoperative rehabilitation, and were followed by Lysholm score 6 months postoperatively.

All 28 patients were males, with a mean age of 27 ± 0.14 years. The right knee was the most commonly affected in 20/28 patients (71.4%). The medial meniscus was most commonly injured in 11 patients, 7 patients had lateral meniscal tears, and 10 patients had tears in both menisci. The most common tear pattern of the medial meniscus was a bucket handle tear (36.4%), while longitudinal tears were the most frequent in the lateral meniscus (71.4%) (P-value = 0.04). The most common radial tear location was zone E-F (5/28, 17.8%), and the most common circumferential zone affected was the middle and inner third, reported in 50% of tears. Good and excellent outcomes using the Lysholm score after 6 months were obtained in 42.9% and 17.9% of patients, respectively. Better functional scores were associated with lateral meniscal tears, bucket handle tears, tears extending to a more peripheral vascular area, and if no more than one-third of the meniscus was resected (P-value = 0.002). Less favourable outcomes were reported in smokers, posterior horn tears, and when surgery was delayed more than 1 year (P-value = 0.03).

We conclude that there is a negative correlation between the amount of meniscus resected and functional outcome. Delayed ACL reconstruction increases the risk of bimeniscal tears. Bucket handle tears are the most common tears, mostly in the medial meniscus, while longitudinal tears are most common in the lateral meniscus. We recommend performing early ACL reconstruction within 12 months to reduce the risk of bimeniscal injuries.

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This study aims to identify the top unanswered research priorities in the field of knee surgery using consensus-based methodology.

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Adenosine, lidocaine, and Mg²⁺ (ALM) therapy exerts differential immuno-inflammatory responses in males and females early after anterior cruciate ligament (ACL) reconstruction (ACLR). Our aim was to investigate sex-specific effects of ALM therapy on joint tissue repair and recovery 28 days after surgery.

Background. Anterior cruciate ligament (ACL) reconstruction with concomitant meniscal injury occurs frequently. Meniscal repair is associated with improved long-term outcomes compared to resection but is also associated with a higher reoperation rate. Knowledge of the risk factors for repair failure may be important in optimizing patient outcomes. Purpose. This study aimed to identify the patient and surgical risk factors for meniscal repair failure, defined as a subsequent meniscectomy, following concurrent primary ACL reconstruction. Methods. Data recorded by the New Zealand ACL Registry and the Accident Compensation Corporation, the New Zealand Government's sole funder of ACL reconstructions and any subsequent surgery, was reviewed. Meniscal repairs performed with concurrent primary ACL reconstruction was included. Root repairs were excluded. Univariate and multivariate survival analysis was performed to identify the patient and surgical risk factors for meniscal repair failure. Results. Between 2014 and 2020, a total of 3,024 meniscal repairs were performed during concurrent primary ACL reconstruction (medial repair = 1,814 and lateral repair = 1,210). The overall failure rate was 6.6% (n = 201) at a mean follow-up of 2.9 years, with a failure occurring in 7.8% of medial meniscal repairs (142 out of 1,814) and 4.9% of lateral meniscal repairs (59 out of 1,210). The risk of medial failure was higher in patients with a hamstring tendon autograft (adjusted HR = 2.20, p = 0.001), patients aged 21–30 years (adjusted HR = 1.60, p = 0.037) and in those with cartilage injury in the medial compartment (adjusted HR = 1.75, p = 0.002). The risk of lateral failure was higher in patients aged ≤ 20 years (adjusted HR = 2.79, p = 0.021) and when the procedure was performed by a surgeon with an annual ACL reconstruction case volume of less than 30 (adjusted HR = 1.84, p = 0.026). Conclusion. When performing meniscal repair during a primary ACL reconstruction, the use of a hamstring tendon autograft, younger age and the presence of concomitant cartilage injury in the medial compartment increases the risk of medial meniscal repair failure, whereas younger age and low surgeon volume increases the risk of lateral meniscal repair failure

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The purpose of this study is to determine an individual’s age-specific prevalence of total knee arthroplasty (TKA) after cruciate ligament surgery, and to identify clinical and genetic risk factors associated with undergoing TKA.

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To identify unanswered questions about the prevention, diagnosis, treatment, and rehabilitation and delivery of care of first-time soft-tissue knee injuries (ligament injuries, patella dislocations, meniscal injuries, and articular cartilage) in children (aged 12 years and older) and adults.