Knee osteoarthritis (KOA) diagnosis is based on symptoms, assessed through questionnaires such as the WOMAC. However, the inconsistency of pain recording and the discrepancy between joint phenotype and symptoms highlight the need for objective biomarkers in KOA diagnosis. To this end, we study relationships among clinical and molecular data in a cohort of women (n=51) with Kellgren-Lawrence grade 2–3 KOA through Support Vector Machine (SVM) and a regulation network model (RNM). Clinical descriptors (i.e., pain catastrophism (CA); depression (DE); functionality (FU); joint pain (JP); rigidity (RI); sensitization (SE); synovitis (SY)) are used to classify patients. A Youden's test is performed for each classifier to determine optimal binarization thresholds for the descriptors. Thresholds are tested against patient stratification according to baseline WOMAC data from the Osteoarthritis Initiative, and the mean accuracy is 0.97. For our cohort, the data used as SVM inputs are KOA descriptors, synovial fluid (SL) proteomic measurements (n=25), and transcription factors (TF) activation obtained from RNM [2] stimulated with the SL measurements. The relative weights after classification reflect input importance. The performance of each classifier is evaluated through AUC-ROC analysis. The best classifier with clinical data is CA (AUC = 0.9), highly influenced by FU and SE, suggesting that kinesophobia is involved in pain perception. With SL input, leptin strongly influences every classifier, suggesting the importance of low-grade inflammation. When TF are used, the mean AUC is limited to 0.608, which can be related to the pleomorphic behaviour of osteoarthritic chondrocytes. Nevertheless, FU has an AUC of 0.7 with strong importance of FOXO downregulation. Though larger and longitudinal cohorts are needed, this unique combination of SVM and RNM shall help to map objectively KOA descriptors.

Acknowledgements: Catalan & Spanish governments 2020FI_b00680; STRATO-PID2021126469ob-C21-2, European Commission (MSCA-TN-ETN-2020-Disc4All-955735, ERC-2021-CoG-O-Health-101044828). ICREA Academia.

While pre-soaking grafts in vancomycin has demonstrated to be effective in observational studies for anterior cruciate ligament reconstruction (ACLR) infection prevention, the economic benefit of the technique is uncertain. The primary aim of this study was to determine the cost-effectiveness of vancomycin pre-soaking during primary ACLR to prevent post-operative joint infections. The secondary aims of the study were to establish the breakeven cost-effectiveness threshold of the technique.

A Markov model was used to determine cost effectiveness and the incremental cost effectiveness ratio of additional vancomycin pre-soaking compared to intravenous antibiotic prophylaxis alone. A repeated meta-analysis of nine cohort studies (Level III evidence) was completed to determine the odds ratio of infection with vancomycin pre-soaking compared to intravenous antibiotics alone. Estimated costs and transitional probabilities for further surgery were obtained from the literature. Breakeven threshold analysis was performed.

The vancomycin soaking technique provides an expected cost saving of $600AUD per patient. There was an improvement in the quality-adjusted life years of 0.007 compared to intravenous antibiotic prophylaxis alone (4.297 versus 4.290). If the infection rate is below 0.023% with intravenous antibiotics alone or the additional intervention cost more than $1000AUD, the vancomycin wrap would no longer be cost-effective.

For $30AUD, the vancomycin soaking technique provides a $600AUD cost saving by both reducing the risk of ACLR related infection and economic burden of infection. Treating septic arthritis represents a mean cost per patient of 6 times compared to that of the primary surgery. There has been no previous cost-effectiveness study of the vancomycin wrap technique.

The vancomycin pre-soaking technique is a highly cost-effective method to prevent post-operative septic arthritis following primary ACLR.

INTRODUCTION

The purpose of this study is to report results from a prospective multicenter study of a bioresorbable type I collagen scaffold used to replace tissue loss following irreparable lateral meniscus injuries.

Purpose

Evaluation of our experience on the treatment of comminuted, radial head fractures, and of the outcomes of pyrocarbon prosthetic replacement in such cases.

INTRODUCTION: Shrinkage is one of the complications observed after allograft meniscal transplantation. Subtle immune rejection and alterations in meniscal permeability leading to nutritional deficit have been suggested as causes of shrinkage. The purpose of this study was to ascertain how freezing, one of the most common procedures used to preserve allografts, alters the collagen’s architecture.

METHODS: 26 fresh human external menisci were harvested in sterile conditions during TKR procedures. 13 of them were immediately frozen to −80° C while the rest were used as controls. All the menisci were cut, processed and preserved in a 2.0% glutaraldehyde and then analyzed with transmission electron microscopy. Four hundred collagen fibrils were recorded and measured in longitudinal and transversal sections in each meniscus. According to the collagen’s periodicity and degree of disruption, loss of banding, degree of collagen packing, fibril size variability and its intrafibrilar oedema, each meniscus was pointed from 0 to 7. Subsequently they were classified in grades ranging from a normal state (grade I; 0 to 2 points) to severe disarray (grade III; 5 to 7 points).

RESULTS: The fibril collagen diameters of those menisci that had been previously frozen showed an average size in the longitudinal section of 14.256 nm, whereas 17.279 nm were seen in the menisci used as controls (p=0.019). In the transverse section, the frozen menisci averaged 13.145 nm and 16.935 nm the controls (p=0.003).

Samples of the 13 previously frozen menisci were classified as grade III in 8 cases (61,54 %), and grade II in 5 cases (38.46 %). They averaged 4.846 points. The control groups were classified as grade I in 6 cases (46.154%) and grade II in 7 cases (53.85 %). The frozen menisci averaged 4.85 points whereas the control group did so 2.46 (p< 0.001)

CONCLUSIONS: The fibril diameters in frozen menisci showed a thinner diameter and had a higher degree of disarray. Therefore, the results suggest that the freezing process alters the menisci’s collagen net. This could partially explain the pathological changes found in shrunken menisci. This is the first work that quantified and qualified methodologically the collagen meniscal architecture and its potential changes.

Introduction and purpose: Fractures of the tibial plateau account for 1% of the total. Among them, 55–70% involve the lateral plateau with differences in separation and subsidence. Minimally invasive osteosynthesis under arthroscopic control increases the indications in these cases. Our purpose is to assess the long-term clinical and radiological outcomes.

Materials and methods: We carried out a retrospective analysis of the medium-term results of closed fractures of the tibial plateau treated with arthroscopic reduction and percutaneous fixation with cannulated screws. A series of 32 patients with displaced fractures of the tibial plateau underwent surgery between 1993 and 2004. We used the AO classification. We analysed the clinical, functional and radiological results.

Results: The mean follow-up was 6 years. We treated 12 type 41B1, 7 type 41B21, 5 type 41B22, 7 type 41B31 and 1 type 41B12. All the fractures were consolidated and 79.1% had anatomical reduction. External meniscal injuries that could be sutured were present In 11 cases (34.3%). Joint balance was complete in 24 knees. According to the Lysholm scale 23 had an excellent outcome and 9 good. One case presented infection of the surgical wound, which was resolved by surgical debridement and antibiotic therapy.

Conclusions: The results suggest that this is a good method for treating selected fractures of the tibial plateau.

Introduction and purpose: To present the clinical, radiological and MRI results of a series of collagen meniscus implants (CMI) with 4–7 years follow-up.

Materials and methods: We implanted 25 CMI from 1997 to 2000 in 20 men and 5 women between the ages of 18 and 48. Five cases were operated on for postmeniscectomy syndrome, 19 for degenerative ruptures and one for acute rupture. We reconstructed the ACL at the same time in 17 cases (68%).

Results: The Lysholm score went from a preoperative mean of 59.9±15.8 to 89.6±6.3 at 2 years (p< 0.003), while the visual analogue pain score went from a preoperative mean of 7.0±1.8 to 2.0±1.6 (p< 0.001).

Conventional radiology showed no deterioration of the joint line. With MRI we saw a certain degree of meniscal regeneration in 68% of the cases. However, the implant tended to become smaller and it was common to see extrusion in frontal sections.

Three cases had persistent pain on the medial side of the knee. In one we removed the CMI and performed an allogeneic meniscus transplantation (AMT). The second case was treated by valgus osteotomy of the tibia and then AMT in the stage. The last case was not treated.

Conclusions: After 4 to 7 years of BMI follow-up, we found no adverse effects for the knee. Clinically the outcome was good in most of the cases (22/25). Regeneration appeared to occur in over one-third of the cases, although the size was smaller than expected.

Introduction: Meniscal extrusion is defined as the situation in which the meniscus is partially or totally luxated from the tibial plateau. The aim of this work is to ascertain the prevalence of meniscal extrusion in non arthritic patients and to define those factors related to it. Special attention was given to the fact of anatomic variations in the menisci attachments.

Methods: The knee MRI of 100 patients that were operated on arthroscopically in our institution was prospectively studied. Seventy-two males and 28 females, average age of 36.6 years (range between 13 and 64), entered in the study. There were 43 right-knees and 57 left-knees. The average weight of the patients was 77 kg (range 44 to 135).

Results: With respect to the medial meniscus 68.9% of the cases showed some degree of extrusion, averaging at 28% of the meniscal size (ranging from 10% to 60%). In the case of the lateral meniscus extrusion averaging 15% (ranging from 10% to 40%) was seen in 18.8% of the cases.

In this series the posterior types of anterior medial meniscus insertion were the most frequently found (69.5%).

Medial meniscal extrusion was significatively correlated to the presence of a chondral lesion (p = 0.008) and to anterior medial meniscus insertion (p = 0.001). No statistical significant relationship to the rest of parameters studied was encountered. None of the parameters studied were related to lateral meniscus extrusion

Discusion: Meniscal extrusion is frequent in our series and, the hypothesis that those patients who have an anterior variant of the anterior horn insertion of the medial meniscus tend to show greater extrusion is confirmed.

Background: The Inferior Glenohumeral Ligament (IGHL) has a well known mechanical and propioceptive relevance in shoulder stability. The interrelation of the IGHL anatomical disposition and innervation has not actually been described. The studys purpose was to determine the IGHL innervation patterns and relate them to dislocation.

Material & methods: Forty-five embalmed and 16 fresh-frozen human cadaveric shoulders were studied. Massons Trichrome staining was used to detail the intra-ligamentous nerve fibre arrangements. Neural behaviour of the articular nerves was studied dynamically at the apprehension position and while anteroinferior dislocation of the shoulder joint was performed.

Results: The anatomy of the IGHL was clearly defined. However, in 7 out of 61 cases the anterior band was only a slight thickening of the ligament. It averaged 34 mm (range, 28 to 46 mm) in length. The posterior band was only seen in 40.98 % of the cases. The axillary nerve provided IGHL innervation in 95.08 % of the cases. We found two distinct innervation patterns originating in the axillary nerve. In Type 1 (29.5 % of the cases), one or two collaterals later diverged from the main trunk to enter the ligament. Type 2 (65.57%) showed innervation to the ligament provided by the posterior branch for three to four neural branches. In both cases, these branches enter the ligament near the glenoid rim and at 7 oclock position (right shoulder). The shortest distance to the glenohumeral capsule was noted at 5 oclock position. The radial nerve (Type 3 innervation pattern) provided IGHL innervation in 3.28 % (2 specimens). Microscopic analysis revealed wavy intraligamentous neural branches. The articular branches relaxed and separated from the capsule at external rotation and abduction and stayed intact after dislocation.

Conclusions: The current results showed the IGHL to have three different innervation patterns. The special neural anatomy of the IGHL suggested it was designed to avoiding denervation when dislocated. This might contribute to understand why the neural arch remains unaffected after most dislocations. To our knowledge this is the first work that clearly describes specimens in which the main innervation of the IGHL is provided by the radial nerve.

Knowledge of the neural anatomy of the shoulder will clearly help in avoiding its injury in surgical procedures.