Anterior Cruciate Ligament Degeneration Research Articles

Small RNA signatures of the anterior cruciate ligament from patients with knee joint osteoarthritis.

Introduction: The anterior cruciate ligament (ACL) is susceptible to degeneration, resulting in joint pain, reduced mobility, and osteoarthritis development. There is currently a paucity of knowledge on how anterior cruciate ligament degeneration and disease leads to osteoarthritis. Small non-coding RNAs (sncRNAs), such as microRNAs and small nucleolar RNA (snoRNA), have diverse roles, including regulation of gene expression. Methods: We profiled the sncRNAs of diseased osteoarthritic ACLs to provide novel insights into osteoarthritis development. Small RNA sequencing from the ACLs of non- or end-stage human osteoarthritic knee joints was performed. Significantly differentially expressed sncRNAs were defined, and bioinformatics analysis was undertaken. Results and Discussion: A total of 184 sncRNAs were differentially expressed: 68 small nucleolar RNAs, 26 small nuclear RNAs (snRNAs), and 90 microRNAs. We identified both novel and recognized (miR-206, -365, and -29b and -29c) osteoarthritis-related microRNAs and other sncRNAs (including SNORD72, SNORD113, and SNORD114). Significant pathway enrichment of differentially expressed miRNAs includes differentiation of the muscle, inflammation, proliferation of chondrocytes, and fibrosis. Putative mRNAs of the microRNA target genes were associated with the canonical pathways "hepatic fibrosis signaling" and "osteoarthritis." The establishing sncRNA signatures of ACL disease during osteoarthritis could serve as novel biomarkers and potential therapeutic targets in ACL degeneration and osteoarthritis development.

The association between anterior cruciate ligament degeneration and incident knee osteoarthritis: Data from the osteoarthritis initiative

BackgroundThough anterior cruciate ligament (ACL) tear has been widely accepted as an important accelerator for knee osteoarthritis (KOA), the role of intrinsic ACL degeneration in developing KOA has not been fully investigated. PurposeTo determine whether ACL degeneration, in the absence of ACL tear, is associated with incident KOA over 4 years. Study designCohort study; Level of evidence, 2. MethodsParticipants’ knees in this nested case–control study were selected from the Osteoarthritis Initiative (OAI) study, with Kellgren–Lawrence grading (KLG) of 0 or 1 ​at baseline (BL). Case knees which had incident KOA (KLG ≥2) over 4 years, were matched 1:1 with control knees by gender, age and radiographic status. ACL signal intensity alteration (0–3 scale) and volume were assessed as compositional feature and morphology of ACL degeneration, using knee MRI at P0 (time of onset of incident KOA), P-1 (1 year prior to P0) and baseline. Conditional logistic regression was applied to analyze the association between measures of ACL degeneration and incident KOA. Results337 case knees with incident KOA were matched to 337 control knees. Participants were mostly female (68.5%), with an average age of 59.9 years old. ACL signal intensity alterations at BL, P-1 and P0 were significantly associated with an increased odds of incident KOA respectively (all P for trend ≤0.001). In contrast, ACL volumes were not significantly associated with incident KOA at any time points. ConclusionsACL signal intensity alteration is associated with increased incident KOA over 4 years, whereas ACL volume is not.The translational potential of this article: This paper focused on ACL signal intensity alteration which could better reflect ACL degeneration rather than ACL tear during the progression of KOA and explored this topic in a nested case–control study. Utilizing MR images from KOA participants, we extracted the imaging features of ACL. In addition, we established a semi-quantitative score for ACL signal intensity alteration and found a significant correlation between it and KOA incidence. Our findings confirmed that the more severe the ACL signal intensity alteration, the stronger relationship with the occurrence of KOA. This suggests that more emphasis should be placed on ACL degeneration rather than ACL integrity in the future.

A new magnetic resonance imaging grading system for anterior cruciate ligament myxoid degeneration in osteoarthritis of the knee

BackgroundThis study aimed to investigate association between magnetic resonance imaging (MRI) and histological findings of degenerated anterior cruciate ligament (ACL) in knee osteoarthritis (OA), and based on this result, to develop a new ACL degeneration grading system by MRI that corresponds to histological findings of degenerated ACL. HypothesisMRI signal intensity of the ACL could correspond to histological findings of collagen degeneration. Patients and methodsA collection of 106 ACL specimens from 85 patients who underwent primary total knee arthroplasty was investigated for signal intensity of the ACL and muscle on axial Fat-saturated proton density-weighted MRI and MRI signal intensity ratio (ACL/muscle) was calculated. The correlation between ACL histological degeneration and MRI ACL/muscle signal intensity ratio was analyzed. The ACL was stratified into 3 grades based on signal intensity relative to muscle intensity (grade 1, low; grade 2, iso; and grade 3, high), and the extent to ACL degeneration in each MRI ACL degeneration grade was evaluated. ResultsCollagen degeneration (53.5±24.0%) and myxoid change (25.2±18.8%) in degenerated ACL significantly correlated with MRI signal intensity ratio of the ACL/muscle (r=0.62, p<0.0001; r=0.67, p<0.0001). ACL were assigned to grade 1 (n=22 [20.8%]), grade 2 (n=56 [52.8%]), and grade 3 (n=28 [26.4%]). ACL collagen degeneration was 34.8±18.4% in grade 1, 49.3±21.7% in grade 2, and 76.6±12.0% in grade 3. ACL myxoid change was 10.0±11.3% in grade 1, 21.3±14.1% in grade 2, and 45.0±15.3% in grade 3. DiscussionThe ACL/muscle signal intensity ratio on MRI correlated with the extent to ACL myxoid degeneration. The new MRI ACL degeneration grade is helpful to estimate the extent to ACL myxoid degeneration in knee OA. Level of evidenceIII; retrospective cohort study.

Clinical outcomes of arthroscopic partial resection of mucoid degeneration of anterior cruciate ligament.

Mucoid degeneration of the anterior cruciate ligament is rare condition; mucoid degeneration affects the range of motion of the knee with pain on terminal extension and terminal flexion. Arthroscopic treatment of the mucoid anterior cruciate ligament (ACL) is the treatment of choice. The purpose of this study was to provide demographic and clinical characteristic of mucoid degeneration of ACL and assess the outcomes of partial arthroscopic ACL resection. Patients who underwent partial ACL resection for mucoid degeneration between February 2007 and February 2019 were considered for study eligibility. Patients were evaluated for International Knee Documentation Committee (IKDC), The Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI), The Knee injury and Osteoarthritis Outcome Score (KOOS) and Tegner activity scale. Sixty patients underwent partial ACL resection for mucoid degeneration of the ACL. Nine patients were lost to follow-up, 43 were males, the average age was 52.12±12.09 and a mean follow-up of 83.55±44.79 months. At final follow-up six patients underwent ACL reconstruction for ACL rupture (11.7%) at an average of 15.66±12 months. Patient satisfaction was at 71%. Arthroscopic partial resection of the ACL led to good clinical outcome for treating mucoid degeneration of the ACL.

Relation entre les modifications histologiques du ligament croisé antérieur et la fonction du genou chez les patients arthrosiques

BackgroundThe function of the anterior cruciate ligament (ACL) in osteoarthritis (OA) of the knee remains to be elucidated. The purpose of this study is to evaluate histological changes of the ACL in end-stage knee OA and to clarify the relationship between histological changes in the ACL and knee function. HypothesisThe hypothesis in this study was that ACL degeneration in knee OA is associated with decreased knee function. Patients and methodsEighty-two ACL specimens from 65 patients who underwent primary total knee arthroplasty (TKA) were investigated. The correlation between histological changes of the ACL (myxoid changes, chondroid metaplasia, total collagen degeneration, microcyst formation, vascular proliferation, and inflammatory cell infiltration) and knee function (range of motion, anterior tibial translation test, knee extension muscle strength, one-leg standing time, and functional reach test) were investigated. Age, body mass index, joint space narrowing, osteophyte formation, lower extremity alignment, and knee medial/lateral instability were also evaluated. ResultsMyxoid change in the ACLs was significantly negatively correlated with one-leg standing time. Chondroid metaplasia was not correlated with knee function. Collagen degeneration in the ACL was significantly negatively correlated with knee flexion angle and one-leg standing time. In addition, a negative correlation between microcyst formation and knee flexion angle was noted. Osteophyte formation, particularly lateral femoral intercondylar osteophytes, was correlated with myxoid changes. The other parameters did not correlate with ACL histological changes. DiscussionMyxoid changes in the ACL were shown to correlate with knee function. The osteophyte score, particularly as related to lateral femoral intercondylar osteophytes, correlated with the severity of myxoid changes in the ACL in knee OA. Precise ACL evaluation should be included in the indications for ACL-retaining surgeries because ACL degeneration may be related to decreased knee function after surgery. Level of evidenceIV, diagnostic case series.

A case of mucoid hypertrophic degeneration of anterior cruciate ligament with ganglion cyst causing extension block treated with arthroscopic debridement of the cyst and partial debulking surgery

&lt;p class="abstract"&gt;&lt;span lang="EN-US"&gt;Mucoid degeneration of anterior cruciate ligament (ACL) is an uncommon cause of knee pain and restriction of movements. It uncommonly presents with a coexisting ACL ganglion cyst. Typically present between ages of 40-60 years, however, the true incidence and symptoms are variable. We present our experience with one such case with loss of knee extension treated with arthroscopic debulking. The patient regained both full range of motion and resolution of symptoms after the treatment.&lt;/span&gt;&lt;/p&gt;

Steep posterior slope of the medial tibial plateau and anterior cruciate ligament degeneration contribute to medial meniscus posterior root tears in young patients.

Medial meniscus posterior root tears (MMPRTs) occur most frequently in middle-aged and older adults. However, this serious condition can also occur in younger patients. The purpose of this study was to compare anterior cruciate ligament (ACL) degeneration and sagittal medial tibial slope in young adults with and without MMPRT. Eighteen healthy volunteers, 18 young patients (20-49years of age), and 30 middle-aged and older patients (50-70years of age) with MMPRT repair were included in the study. Sex, body mass index (BMI), femorotibial angle, ACL degeneration, and medial tibial slope angle were compared among the groups. ACL degeneration and medial tibial slope angle were assessed using magnetic resonance imaging. In the healthy volunteer group, the young patient group, and the older patient group, the medial tibial slopes were 3.5° ± 1.4°, 6.1° ± 2.7°, and 7.2° ± 1.9°, respectively, and the ACL degeneration rates were 5.6%, 38.9%, and 43.3%, respectively. Young patients with MMPRT had significantly steeper medial tibial slopes and ACL degeneration compared to those of the healthy volunteers (P < 0.05). The parameters of young patients were similar to those of older patients with MMPRT. In the multivariate logistic regression analysis, BMI, medial tibial slope, and ACL degeneration were significantly associated with MMPRT in young patients. BMI, steep medial tibial slope, and ACL degeneration contribute to MMPRT development in younger patients. Level III.

Relationship between histological changes of the anterior cruciate ligament and knee function in osteoarthritis patients

BackgroundThe function of the anterior cruciate ligament (ACL) in osteoarthritis (OA) of the knee remains to be elucidated. The purpose of this study is to evaluate histological changes of the ACL in end-stage knee OA and to clarify the relationship between histological changes in the ACL and knee function. HypothesisThe hypothesis in this study was that ACL degeneration in knee OA is associated with decreased knee function. Patients and methodsEighty-two ACL specimens from 65 patients who underwent primary total knee arthroplasty (TKA) were investigated. The correlation between histological changes of the ACL (myxoid changes, chondroid metaplasia, total collagen degeneration, microcyst formation, vascular proliferation, and inflammatory cell infiltration) and knee function (range of motion, anterior tibial translation test, knee extension muscle strength, one-leg standing time, and functional reach test) were investigated. Age, body mass index, joint space narrowing, osteophyte formation, lower extremity alignment, and knee medial/lateral instability were also evaluated. ResultsMyxoid change in the ACLs was significantly negatively correlated with one-leg standing time. Chondroid metaplasia was not correlated with knee function. Collagen degeneration in the ACL was significantly negatively correlated with knee flexion angle and one-leg standing time. In addition, a negative correlation between microcyst formation and knee flexion angle was noted. Osteophyte formation, particularly lateral femoral intercondylar osteophytes, was correlated with myxoid changes. The other parameters did not correlate with ACL histological changes. DiscussionMyxoid changes in the ACL were shown to correlate with knee function. The osteophyte score, particularly as related to lateral femoral intercondylar osteophytes, correlated with the severity of myxoid changes in the ACL in knee OA. Precise ACL evaluation should be included in the indications for ACL-retaining surgeries because ACL degeneration may be related to decreased knee function after surgery. Level of evidenceIV, Diagnostic case series.

Management of hypertrophic anterior cruciate ligament mucoid degeneration by arthroscopy

Introduction: Mucoid degeneration of the anterior cruciate ligament (ACL) is a less common entity. The primary pathology is the damage to the functional synovial lining protecting the ACL with no significant preceding trauma. Two types are described i.e., cystic (synovial and mucoid cysts) and infiltrating (mucoid degeneration). These lesions can be asymptomatic. When symptomatic, the patient complained of posterior knee pain with restriction of flexion in the knee. The diagnosis is confirmed by Magnetic Resonance Imaging of the Knee. Recent trends include arthroscopic procedures, including ACL debridement, i.e. partial resection. Total resection can be required in a few cases with ACL reconstruction. Inclusion Criteria: Diagnosed cases of ACL mucoid degeneration on MRI. Exclusion Criteria: Post-traumatic knee injuries-meniscal or ligamentous or bony, ACL synovial or mucoid cysts. Materials and Methods: A total of 18 patients diagnosed with ACL mucoid degeneration were included in the study. The study was conducted from August 2019-August 2021. The patients were assessed clinically with history and clinical examination. MRI was advised in patients with clinical suspicion of ACL mucoid degeneration. Results: The study sample consisted of 18 patients (7 females and 11 males) with ages ranging from 30 to 55 years (mean age, 43.2 years) in males and 35 to 55 years (mean age, 41.5 years) in females. On clinical assessment, exacerbation of pain was more commonly related with terminal flexion in 10 patients (58.8%) as compared to terminal extension (7 patients, 41%). No motion-related exacerbation of pain was seen in 1 case. 17 patients had an extension deficit. No complaint of instability was seen except for 2 cases. Postoperatively an average improvement of the Visual analogue scale by 4 was seen. No flexion or extension deformity was noted. No patient had any major complication. On follow up Anterior Lachman test was grade 1 in 16 cases and in others it was same as opposite non-affected knee. A complete resection of ACL with reconstruction using hamstring graft was done in 1 patient. The same patient showed a pain improvement of 4 scales on VAS. The patient however had episodes of instability. Conclusion: A clinical suspicion of mucoid degeneration of ACL with confirmatory classical appearance on MRI are key to diagnosis. Symptomatic pain relief is better provided with ACL debridement with mild laxity in upcoming future.

Anterior cruciate ligament innervation in primary knee osteoarthritis.

To relate the Anterior Cruciate Ligament (ACL) innervation and histologic degeneration status to the knee osteoarthritis radiologic and functional status. Prospective observational study including 30 consecutive patients affected by primary knee osteoarthritis undergoing Total Knee Arthroplasty (TKA). All patients suffering secondary knee osteoarthritis, an antecedent of an infectious process, malignant process, autoimmune disorder, or previous knee surgery were excluded. We recorded biodemographic, clinical, and radiologic variables of all participants previous to the TKA procedure. ACL tissue was harvested during TKA standard procedure and the obtained sample was fixed in 4% formalin and paraffin-embedded. ACL cross-sections were stained by haematoxylin-eosin and Gallego staining for elastic and collagen fibers, and Sevier-Munger silver staining for nervous tissue. ACL samples histologic degeneration classification reported 15.4% normal, 23.1% slight, 26.9% mild, 11.5% moderate and 23.1% marked. We noted 46.2% large nervous fascicles, 15.4% medium fascicles, 3.8% small fascicles, and no nerve fibers were found in 34.6% ACL samples. No significant correlation was found between the histologic degeneration and the nervous fiber quantification (p>0.05, in all cases). We noted a significant histologic degeneration inverse correlation with the VAS scale (p=0.016), and nervous fiber quantification correlation with Lequesne maximum distance walked punctuation (p=0.043). We also noted greater nervous fiber quantification with minor radiological knee osteoarthritis (Kellgren-Lawrence grade II). ACL degeneration and innervation deficit may play a role in primary knee osteoarthritis onset, but the lack of a defining relationship among the different parameters assessed justifies further research in greater populations.

TRNA-derived fragment TRF365 regulates the metabolism of anterior cruciate ligament cells by targeting IKBKB

tRNA-derived fragments (tRFs) are new noncoding RNAs, and recent studies have shown that tRNAs and tRFs have important functions in cell metabolism via posttranscriptional regulation of gene expression. However, whether tRFs regulate cellular metabolism of the anterior cruciate ligament (ACL) remains elusive. The aim of this study was to investigate the role and action mechanism of tRFs in ACL cell metabolism. A tRF array was used to determine tRF expression profiles in different human ACL cells, and quantitative real-time polymerase chain reaction and fluorescence in situ hybridisation were used to determine TRF365 expression. ACL cells were transfected with a TRF365 mimic or a TRF365 inhibitor to determine whether TRF365 regulates IKBKB expression. A rescue experiment and dual-luciferase reporter assay were conducted to determine whether the 3′-untranslated region (UTR) of IKBKB has a TRF365-binding site. TRF365 was weakly expressed in osteoarthritis (OA) ACL and interleukin-1β-treated ACL cells. IKBKB was highly expressed in OA ACL and interleukin-1β-treated ACL cells; transfection with the TRF365 mimic suppressed IKBKB expression, whereas transfection with the TRF365 inhibitor had the opposite effect. A dual-luciferase reporter assay showed that TRF365 silenced the expression of IKBKB by binding to its 3′-UTR. Thus, TRF365 regulates the metabolism of ACL cells by targeting IKBKB. In summary, TRF365 may provide a new direction for the study of ACL degeneration and on the pathophysiological process of OA.

Mucoid degeneration of the anterior cruciate ligament: A case study

Mucoid degeneration of anterior cruciate ligament (ACL) is a rare pathological condition characterized by knee pain and restriction of movements. In this condition, ACL is infiltrated by mucoid (glycosaminoglycans) like material within its substance. We discuss the case and present a review of literature including clinical and radiological features and management options. We encountered a 33-year-old female complaining of increasing pain in right knee since last 6 years with difficulty in squatting and sitting cross-legged. There was no history of significant trauma or instability of the knee. Clinical examination demonstrated pain on deep knee flexion, negative Lachman, and anterior drawer test. Plain radiograph of knee suggested early onset degenerative changes of knee in the form of medial joint space reduction. Magnetic resonance imaging (MRI) showed hyperintense signal in ACL substance in T1W and T2W images which is classically described as Celery Stalk appearance on T2 STIR images. This was often mistaken as partial tear of ACL. Patient was planned for diagnostic arthroscopy. During arthroscopy, ACL was occupying the whole intercondylar notch. It was hypertrophied, homogenous, and firm. Arthroscopic debulking of ACL was done cautiously and mucoid tissue was removed. The specimen was sent for histopathological examination which confirmed the diagnosis of mucoid degeneration. Post-operatively patient was relieved of symptoms and was doing well without any specific complaints like instability till last follow up at 18 months. Repeat MRI was not done as patient was not symptomatic. Mucoid ACL degeneration affects active persons in third to fourth decade of life without significant trauma. MRI is the most useful tool for diagnosis with specific findings. If this disease is considered preoperatively, it can be diagnosed early. Treatment with debulking or partial resection shows good functional results.

Correlation of notch width index in knees with mucoid degeneration of anterior cruciate ligament to normal knees

Background: Notch width index (NWI) is a most widely used two dimensional measurement of Intercondylar notch volume of the knee. ACL with mucoid degeneration if often underdiagnosed or overlooked cause of nonspecific knee pain and mild restriction of knee movements. ACL in this condition appears bulky and characteristically shows mucinous material along its fibers. We aim to find any correlation of Notch width index in knees with mucoid degeneration of ACL to knees of age matched controls. Methods: In this study, 32 patients diagnosed with Mucoid degeneration of ACL based on Magnetic Resonance studies were included. Notch width Index i, e width of the intercondylar notch divided by intercondylar width at 2/3 notch depth was measured on a coronal section on MRI. This data was compared with age matched controls using Pearson’s correlation Co efficient. Results: 22 patients in study group were females and 10 were males with age ranging from 25-73 years (Median age 45.5 years) The NWI in Mucoid degeneration of ACL when compared to normal knees showed a significant decrease (NWI -0.222±0.03 Mean in Mucoid ACL group; NWI- 0.311±0.03 in controls) in Intercondylar notch width viz Notch stenosis. Female patients compared to male had decreased NWI with 0.222 Mean. Conclusions: Mucoid degeneration of ACL leading to bulky ACL causing stenosis of the notch is evident in this study. However larger sampling size and volumetric analysis by other methods are needed to better manage this poorly understood condition.

Role of ultrasound-guided decompression in management of mucoid degeneration of the anterior cruciate ligament.

To assess the effectiveness of ultrasound-guided decompression in managing symptomatic mucoid degeneration of the anterior cruciate ligament (ACL). Retrospective analysis of 55 patients who underwent ultrasound-guided ACL mucoid degeneration decompression between July 2013 and August 2019. Subjective satisfaction scores were gathered immediately post-procedure for all 55 patients; follow-up satisfaction scores (scale of 0-10, 10 being excellent) were gathered telephonically for 46 patients (83.6%) up to 63months post-procedure. Follow-up duration of each patient was classified as short (1-6months), intermediate (7-12months), or long (more than 12months) post-procedure. Forty-five patients (81.8%) MRI were retrospectively analyzed and classified into cystic (n = 13, 28.9%), mucoid (n = 11, 24.4%), or mucoid-cystic (21, 46.7%) types. Multivariate logistic regression was used to identify associations between follow-up satisfaction score, follow-up duration, patient age, and type of ACL degeneration. All patients had immediate marked post-procedure improvement, with excellent (>7/10) satisfaction scores. Forty-six of 55 patients were telephonically followed up: 21 (45.6%) short-term interval, 18 (39.1%) intermediate term, and 7 (15.2%) long-term. Thirty (65.22%) patients had excellent and eight (17.4%) patients had average satisfaction scores at follow-up. Eight (17.4%) patients had poor post-procedure satisfaction scores within six months. There were no significant associations between immediate or follow-up satisfaction score and duration of follow-up, age of patient, or type of ACL degeneration. Ultrasound-guided aspiration, fenestration, and injection are an effective, safe, minimally invasive and radiation-free technique for management of mucoid degeneration of ACL with excellent immediate- and long-term results.

Small non-coding RNA signatures of healthy and diseased anterior cruciate ligament

Purpose: Ligaments are short bands of fibrous connective tissue responsible for transmitting load from bone to bone across joints and guiding normal joint motion. Cruciate ligaments within the human knee joint, in particular the anterior cruciate ligament (ACL), are susceptible to degeneration, resulting in pain, reduced mobility and development of the degenerative joint disease of osteoarthritis (OA). There is currently a paucity of knowledge on how ACL degeneration and disease can lead to OA. Small non-coding RNAs (sncRNAs), such as microRNAs (miRs) and small nucleolar RNA (snoRNA), are emerging as important regulators of gene expression.

Dexamethasone causes calcium deposition and degeneration in human anterior cruciate ligament cells through endoplasmic reticulum stress

BackgroundDexamethasone is widely used in the treatment of joint diseases due to its anti-inflammatory properties. However, it can cause serious adverse effects. The anterior cruciate ligament (ACL) is an important stabilizer of the knee joint. However, the effect of dexamethasone treatment on the ACL is unclear. ObjectiveThis study aims to explore the effects of dexamethasone on ACL tissues and cells through in vitro and in vivo experiments. ResultsIn vitro, we found that after treatment with dexamethasone, human ACL cell apoptosis was increased, type I collagen (COL1A1) content was decreased, mineralization related genes (ENPP1 and ANKH) and calcified nodules were increased, and endoplasmic reticulum stress (ERS) was enhanced. However, ERS inhibitors could significantly inhibit the increase in calcification and the decrease in COL1A1 induced by dexamethasone. In vivo, Wistar rats received the infra-articular injection with dexamethasone (0.5 mg/kg) for 8 weeks. We found that dexamethasone treatment decreased the COL1A1 content and increased the COL2A1 content in the ACL tissues of rats and that chondroid differentiation and mineralization occurred. Meanwhile, the expression of ERS-related proteins was increased. ConclusionDexamethasone increased the calcification of ACL cells and caused ACL degeneration through ERS, suggesting that long-term treatment with dexamethasone may cause adverse effects on ACL tissue and increase the risk of long-term rupture.

Anterior translation of the tibia in relation to femur in mucoid degeneration of ACL – An observational study

BackgroundMucoid degeneration (MD) of the anterior cruciate ligament (ACL) are a well-known pathological entity.We have encountered several patients with MD of the ACL, found to have a anterior translation of tibia a exceeding 5 mm with an intact ACL. We studied this cohort and investigated the likely cause of this. MethodsA retrospective search of our department's radiology system to identify all patients referred from the knee orthopaedic clinic for MR imaging over a span of 10 years. All patients had MD within the substance of the ACL and an intact ACL. We evaluated the degree of anterior translation of the tibia (ATT) in relation to the femur in mucoid degeneration of ACL. ResultsWe identified 464 consecutive cases. The mean age was 52 years. There was a male predominance of 261 to 203 female. The average PTF measurement was 2.4 mm with a range of 0-20mm. Of the 464 cases, 397 patients had an insignificant ATT of < 5 mm. (0mm) 67 patients had a ATT >5 mm. Of them, 32.8% had a ATT of 6 mm, 53.7% had a ATT range between 7 and 9 mm, with the remaining 13.4% above 9 mm in length. ConclusionIt is essential to look for other secondary signs of ACL tears and not only focus on ATT as well as correlate this with clinical findings.

Relationship between Femoral Intercondylar Notch Narrowing in Radiography and Anatomical and Histopathologic Integrity of Anterior Cruciate Ligament in Patients Undergoing Total Knee Replacement Surgery.

The presence of cruciate ligaments is very important for normal knee kinematics. Knee arthroplasty prostheses, in which these ligaments are maintained, have better kinematics. The aim of the present study was to investigate the association between femoral intercondylar notch (FIN) narrowing in radiography and clinical and histopathologic integrity of anterior cruciate ligament (ACL) in patients undergoing knee replacement surgery. FIN index was measured in tunnel view radiography of the knees of 102 candidates of knee replacement surgery. The anatomical status of ACL was also examined during total knee arthroplasty (TKA). ACL was removed and sent for histopathologic examination to assess its degeneration rate. The association between the FIN index and the clinical and histopathological health of ACL was investigated. Among 102 patients with mean age of 69.73 ± 7.81 years , 39 patients (38.32%) had no or torn ACL, 31 patients (30.39%) had weak ACL, and 32 (31.37%) had normal ACL. There was a significant association between age and clinical status of ACL during surgery (P=0.017). There was a significant difference in FIN and ACL health status during surgery between the two groups with an index of more and less than 0.252 (P=0.019 and P=0.019, respectively). There was no significant difference in the mean total degeneration score (TDS) of ACL between the two groups with FIN more and less than 0.252 (P=0.816). There was a significant difference between the age and FIN narrowing (less than 0.252) as well as ACL clinical status during surgery. FIN narrowing had no significant effect on the severity of ACL degeneration and there was no significant difference in the severity of degenerative histopathologic changes between healthy and attenuated ACLs. This indicates that if ACL exists, although apparently attenuated, it has the histologic characteristic of a healthy ligament.

Influence de l’augmentation de la pente tibiale sur l’état du ligament croisé antérieur après ostéotomie tibiale d’ouverture de valgisation dans une population de genou à ligament croisé antérieur intact

PurposeThe purpose of this study was to clarify the relationship between posterior tibial slope angle (PTSA) and anterior cruciate ligament (ACL) status in medial open wedge high tibial osteotomy (OWHTO). Our hypothesis was that even though OWHTO may improve anteroposterior laxity of the knee, an increase in PTSA after OWHTO would be associated with ACL degeneration. MethodsSeventy-five patients treated with OWHTO were retrospectively analyzed. PTSA were evaluated radiographically pre- and postoperatively. The ACL was evaluated during the index arthroscopy at the time of OWHTO and a second-look arthroscopy during the plate removal, and scored from 1 (normal ACL) to 4 (complete tear). An anterior tibial translation (ATT) test was performed. ResultsThe mean time period from the index to second-look arthroscopy was 15.0±4.4 months. PTSA significantly increased from 5.3±3.4° preoperatively to 7.5±4.0° postoperatively (p<0.001). The average ACL score significantly increased from 1.9±0.5 at the index arthroscopy to 2.2±0.5 at the second-look arthroscopy (p=0.0025). The average ATT on the operated side significantly decreased from 7.1±2.6mm preoperatively to 5.3±2.3mm at the second look arthroscopy (p<0.0001). There was a significant positive correlation between the increase in PTSA and the change of ACL grade (Correlation coefficient (r)=0.221, p<0.05). ConclusionEven though OWHTO reduces anteroposterior knee laxity, an increase in PTSA is associated with ACL degeneration. It is important for the surgeon to avoid an increase in PTSA during the procedure to prevent ACL degeneration after OWHTO. Level of EvidenceIV, therapeutic retrospective case series.

A new method for diagnosing biochemical abnormalities of anterior cruciate ligament (ACL) in human knees: A Raman spectroscopic study

Anterior cruciate ligament (ACL) plays an essential role in knee joint stability and kinematics. The microstructural irregularities such as cellular changes and disorganization of the extracellular matrix (ECM) alter the mechanical properties of the ligament, leading to a significant knee functional instability and progression of osteoarthritis (OA). So far, the identification of the local abnormality in ACL has routinely relied on invasive analytical techniques such as histology or biochemical assays. The non-invasive diagnosis using magnetic resonance imaging (MRI) is still limited to identifying the presence/absence of partial/complete ruptures and mucoid degeneration. In this study, laser micro-Raman spectroscopy with near-infrared excitation (785 nm) was applied to human ACL in order to establish optical algorithms for non-destructively diagnosing a degeneration state at molecular level.Raman spectra were obtained from 44 ex-vivo ACL specimens, and these were subsequently classified as an early (subclinical) and advanced (clinical) level of tissue degradation based on the histopathological scoring system. The significant differences in Raman peak intensities were found between the different degeneration groups, which were assigned to the vibrational modes of nucleic acids in cells, collagens, and phospholipids. Linear discriminant analysis (LDA) was performed to identify cut-off values for the distributions of Raman intensity and intensity ratios, which enable to best discriminate between the early and advanced degenerated tissues. Raman intensity algorithms derived from I1101/I1749, [I1002/I1516vs. I1101/I1749], and [I1002/I1749vs. I1101/I1749], yielded a maximum diagnostic sensitivity of 100%, specificity of 80%, and accuracy of 91% for discriminating the degeneration severity. Statement of SignificanceIn this study, laser micro-Raman spectroscopy was applied to human anterior cruciate ligament (ACL) to establish optical algorithms for non-destructively diagnosing the tissue degeneration at molecular level. To our knowledge, this is the first report on Raman diagnosis for human ACL. Linear discriminant analysis (LDA) was performed to identify cut-off values for Raman intensity and intensity ratios, which enable to best discriminate between an early (subclinical) and advanced (clinical) level of ACL degeneration. The intensity ratios of I1101/I1749, [I1002/I1516vs. I1101/I1749], and [I1002/I1749vs. I1101/I1749] yielded a maximum diagnostic sensitivity of 100%, specificity of 80%, and accuracy of 91% for discriminating the ACL degeneration. The present findings might contribute to expanding clinical diagnostic possibilities for non-invasively identifying tissue degeneration.