Reconstruction Considerations Following Complete Excision of Mucoid-Degenerated Anterior Cruciate Ligament: A Retrospective Study

INTRODUCTION

Mucoid degeneration (MD) of the anterior cruciate ligament (ACL) is an unusual cause of knee pain and restricted movement, predominantly affecting the middle-aged population. Arthroscopic partial or total debridement of the mucoid ACL is the surgical treatment of choice. However, little is discussed in the literature regarding subsequent knee instability and functional outcomes following complete ACL excision.

METHODS

A retrospective study was conducted on patients who underwent arthroscopic total ACL excision for mucoid ACL. Pre- and post-operatively, the Tegner-Lysholm score, the International Knee Documentation Committee (IKDC) Subjective Knee Form, and subjective functional instability were used to grade the clinical outcomes.

RESULTS

Ten out of the 13 patients who underwent complete ACL excision were available for evaluation. All patients presented with knee pain on deep flexion or extension with a painfully limited range of motion. Post-operatively, all patients were relieved of their original pain and dysfunction. The mean post-operative IKDC and Tegner-Lysholm scores were 74.96 and 83.6, respectively. All patients had a Lachman test positive, while only two had a grade 1 pivot shift test positive. Two patients had occasional functional instability only after strenuous exercises. None of the patients underwent subsequent ACL reconstruction.

CONCLUSION

All patients reported improved functional outcomes. Only two out of 10 reported occasional instability during strenuous activity. Therefore, complete debridement of mucoid ACL in sedentary patients is safe and efficacious. However, active young patients may experience instability and require ACL reconstruction if it hinders their daily activities.

Patellar height: an important parameter in knee MRI associated with tendinopathy, quadriceps fat pad edema (QFPE), anterior cruciate ligament mucoid degeneration (ACL-MD), and lateral cartilage damage

BACKGROUND

Some pathologies associated with abnormal patellar height have been reported in the literature. However, its relationship with some pathologies, such as anterior cruciate ligament mucoid degeneration (ACL-MD) and focal cartilage defect, has not been investigated.

PURPOSE

To investigate the relationship between patellar height with patellar-quadriceps tendinopathy, quadriceps fat pad edema, ACL-MD, and focal cartilage defect.

MATERIAL AND METHODS

Magnetic resonance imaging of the knees of 261 patients were classified into three groups as normal, patella alta, and patella baja, and evaluated in terms of patellar-quadriceps tendinopathy, quadriceps fat pad edema, ACL-MD, and focal cartilage defect.

RESULTS

There were 261 patients (140 men, 121 women; age range = 18-60 years; mean age = 30 ± 4.7 years). Of the 261 patients, 181 (69.3%) were normal, 56 (21.4%) were patella alta, and 24 were patella baja (9.1%). Patellar-quadriceps tendinopathy, quadriceps fat pad edema, and ACL-MD rates were significantly higher compared to the normal group (P <0.05). While a moderate positive correlation was found between patellar height shift and patellar-quadriceps tendinopathy and ACL-MD, there was a small correlation between patellar height shift and quadriceps fat pad edema. The rate of focal cartilage defect was significantly higher in the middle part of the lateral femoral condyle and lateral knee joint only in patella alta.

CONCLUSION

The risk of patellar-quadriceps tendinopathy, quadriceps fat pad edema, ACL-MD, and lateral focal cartilage defect is higher in patients with alta-baja. The radiologist should evaluate these pathologies more carefully, especially subtle ones, in patients with abnormal patellar height.

Mucoid Degeneration of the Anterior Cruciate Ligament: A Case Report

Mucoid degeneration (MD) is an uncommon pathological phenomenon that specifically affects the anterior cruciate ligament (ACL). This condition arises from the infiltration of yellowish material within the fibers of the ACL, contributing to the clinical presentation characterized by discomfort and limited mobility. MRI has proven to be the foremost diagnostic modality in effectively distinguishing MD of ACL from other potential pathologies. Preoperative recognition of this condition facilitates straightforward diagnosis, particularly via characteristic findings observed during knee arthroscopy. We present a case of MD of ACL, review prior studies about the condition, and outline its clinical features and symptoms, including those observed in our specific case.

Ancillary findings in distinguishing between anterior cruciate ligament mucoid degeneration and sprain on MRI: a practical approach

BACKGROUND

Imaging findings of both anterior cruciate ligament (ACL) sprain and mucoid degeneration overlap in some cases, which may cause errors in magnetic resonance imaging (MRI) evaluation.

PURPOSE

To determine the ancillary findings on MRI in distinguishing between ACL sprain and mucoid degeneration, and also to obtain a diagnostic scheme.

MATERIAL AND METHODS

MRI scans of 77 patients with ACL mucoid degeneration and 77 cases with ACL sprain were retrospectively evaluated to compare with regard to parameters of age, sex, side, the status of posterior cruciate ligament - medial collateral ligament - lateral collateral ligament, bone marrow edema, intraosseous cyst, subchondral sclerosis, chondromalacia, meniscus tear, effusion, and osteochondral body. A decision tree algorithm was created to predict pathology in ACL, whether it was a sprain or mucoid degeneration.

RESULTS

The prevalence of female sex, femoral intraosseous cyst, tibial intraosseous cyst, subchondral sclerosis, femoral chondromalacia, tibial chondromalacia, medial meniscus tear, and lateral meniscus tear were significantly higher in the ACL mucoid degeneration group (P < 0.001, P = 0.016, P < 0.001, P = 0.003, P < 0.001, P < 0.001, P < 0.001, and P < 0.001, respectively). The probability of being mucoid degeneration increased 41.2 times (95% confidence interval [CI] = 5.296-321.132) in cases with tibial intraosseous cyst and increased 1.05 times (95% CI = 1.010-1.080) with each one-year increase in age (P < 0.001 and P = 0.011, respectively). The decision tree algorithm had an overall accuracy of 79.2%.

CONCLUSION

Ancillary findings are helpful in the diagnosis of suspicious cases for ACL mucoid degeneration and ACL sprain. The decision tree algorithm offers a practical and successful approach to this issue.

Mucoid degeneration of the anterior cruciate ligament: can platelet-rich plasma combined with reductionplasty provide better results?

Introduction: Mucoid degeneration of the anterior cruciate ligament (ACL) is commonly treated with arthroscopic debridement of the ACL. But many studies have reported the weakening and laxity of ACL postoperatively and on follow-up. Platelet-rich plasma (PRP) is known to influence musculoskeletal healing through multiple growth factors. Methodology: Five patients who were diagnosed as a case of mucoid degeneration of the ACL based on MRI, over a period of 1 year (December 2018-2019), were included in the study. Autologous PRP, prepared by double spin protocol, was injected into the remaining ACL after partial debridement was done. Results: Visual analogue scale and Lysholm scores improved compared with preoperative scores, along with strength (anterior drawer test and Lachman test). Conclusion: PRP can be used to improve the healing and strength of a weakened ACL after partial debridement, but further research is needed to demonstrate its efficacy.

Inhibition of glucose use improves structural recovery of injured Achilles tendon in mice

Injured tendons do not regain their native structure except at fetal or very young ages. Healing tendons often show mucoid degeneration involving accumulation of sulfated glycosaminoglycans (GAGs), but its etiology and molecular base have not been studied substantially. We hypothesized that quality and quantity of gene expression involving the synthesis of proteoglycans having sulfated GAGs are altered in injured tendons and that a reduction in synthesis of sulfated GAGs improves structural and functional recovery of injured tendons. C57BL6/j mice were subjected to Achilles tendon tenotomy surgery. The injured tendons accumulated sulfate proteoglycans as early as 1-week postsurgery and continued so by 4-week postsurgery. Transcriptome analysis revealed upregulation of a wide range of proteoglycan genes that have sulfated GAGs in the injured tendons 1 and 3 weeks postsurgery. Genes critical for enzymatic reaction of initiation and elongation of chondroitin sulfate GAG chains were also upregulated. After the surgery, mice were treated with the 2-deoxy-d-glucose (2DG) that inhibits conversion of glucose to glucose-6-phosphate, an initial step of glucose metabolism as an energy source and precursors of monosaccharides of GAGs. The 2DG treatment reduced accumulation of sulfated proteoglycans, improved collagen fiber alignment, and reduced the cross-sectional area of the injured tendons. The modulus of the 2DG-treated groups was higher than that in the vehicle group, but not of statistical significance. Our findings suggest that mucoid degeneration in injured tendons may result from the upregulated expression of genes involved the synthesis of sulfate proteoglycans and can be inhibited by reduction of glucose utilization.

Systemic mucoid degeneration of the arterial tunica intima in a young dog

A 27-mo-old, spayed female mixed-breed dog was presented with left forelimb pain, which progressed to full thickness necrosis of the soft tissues of multiple limbs. Clinical imaging and postmortem examination suggested multiple large arterial thromboemboli. Histologic examination of vascular lesions revealed markedly thickened tunica intima with polypoid intraluminal projections, which partially to entirely occluded the arterial lumen. The expanded tunica intima was comprised of intimal accumulation of Alcian blue-positive matrix with scattered spindle-to-satellite cells. These cells were positive for von Willebrand factor and vimentin but negative for α-smooth muscle actin, suggesting endothelial origin. Deposition of the intimal mucoid matrix was observed in the elastic and muscular arteries associated with regional ischemic changes. Mucoid emboli, likely from fragmentation of proliferative intimal tissue, were identified in smaller vessels supplied by affected arteries. Based on these findings, we diagnosed systemic mucoid degeneration of the arterial tunica intima. Such systemic arterial degeneration characterized by deposition of mucoid matrix in the tunica intima has not been reported previously in dogs, to our knowledge, and should be distinguished from thromboembolism and other degenerative vascular diseases.

Clinical Outcomes of Arthroscopic Notchplasty and Partial Resection for Mucoid Degeneration of the Anterior Cruciate Ligament

Background: Mucoid degeneration of the anterior cruciate ligament (MD-ACL) is a chronic degenerative process involving a hypertrophied ACL, which may lead to notch impingement syndrome. As a treatment method, there is consensus regarding arthroscopic resection for MD-ACL resulting in good clinical outcomes; however, additional notchplasty remains controversial. The purpose of this study was to investigate clinical outcomes after arthroscopic partial resection of the ACL and additional notchplasty performed to minimize volume reduction of the ACL. Study Design: Level IIIb retrospective cohort study. Methods: Of 1810 individuals who underwent knee arthroscopic surgery performed by the same surgeon between July 2011 and October 2020, 52 were included, while 10 were excluded due to a follow-up period of <1 year. Clinical data including pain location, terminal flexion or extension pain, range of motion (ROM), Lysholm knee score, and Hospital for Special Surgery (HSS) knee score were assessed pre- and postoperatively. Additionally, according to the resected volume of the ACL, patients were classified into two groups: <25% (Group 1), and 25–50% (Group 2). Clinical outcomes were compared between the two groups. Results: There were 17 (40.5%) men and 25 (59.5%) women with a mean age of 53.9 years (range, 16–81 years) at the time of surgery. The mean duration of symptoms before surgery was 14.4 months (range, 3–66 months). Arthroscopic partial resection of the MD-ACL was performed in all patients, and concomitant notchplasty was performed in 36 (81.8%). All clinical scores improved postoperatively, and were statistically significant (p < 0.01). However, there was no significant difference in clinical outcomes between groups 1 and 2 classified according to the resected ACL volume. Recurrence of MD-ACL was recorded in only one patient, 11 months after arthroscopic treatment. No patients underwent ACL reconstruction because of symptoms of anterior instability. Conclusion: Arthroscopic partial resection of the ACL and concomitant notchplasty yielded satisfactory outcomes for the treatment of MD-ACL. Notchplasty may be an alternative procedure to avoid total ACL resection and postoperative instability.

Association Between MRI-Based Tibial Slope Measurements and Mucoid Degeneration of the Anterior Cruciate Ligament: A Propensity Score-Matched Case-Control Study

Background

The cause of mucoid degeneration (MD) of the anterior cruciate ligament (ACL), which is commonly observed on magnetic resonance imaging (MRI) of patients with knee pain, has yet to be elucidated. Despite the limited evidence on the relationship between ACL lesions (injury and MD) and tibial morphologic features (ie, posterior tibial slope), the potential association between the presence of ACL MD and medial and lateral tibial slope (MTS and LTS) has not been well-established.

Purpose

To investigate whether MTS and LTS measurements are associated with the presence of ACL MD.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Consecutive knee MRI examinations of patients referred by an orthopaedic surgeon for potential internal joint derangements were identified within a 4-year period. The presence of ACL MD and the MTS/LTS values were assessed by independent expert observers in consensus in a blinded fashion. From 413 consecutive knee MRI scans, a sample of 80 knees, including 32 knees with ACL MD (cases) and 48 knees with normal ACL (controls), were selected using propensity score matching method for age, sex, body mass index, and presence of severe medial tibiofemoral compartment cartilage damage. The association between ACL MD and MTS/LTS was evaluated using conditional regression models.

Results

Knees with ACL MD had higher values of LTS (mean ± SD, 7.18° ± 3.58°) in comparison with control knees (5.32° ± 3.35°). Conditional regression analysis revealed a significant association between LTS measurements (not MTS) and ACL MD; every 1° increase in LTS was associated with a 17% (95% CI, 1%-35%) higher probability of having ACL MD.

Conclusion

Excessive LTS was associated with the presence of ACL MD, independent of participants' age, sex, BMI, and cartilage damage severity.

A Retrospective Comparison of ACL Tear and Mucoid Degeneration MRI Findings and an Emphasis on Evaluating of ACL, Blumensaat, and PCL Angles

Objective:

To determine MRI findings that can differentiate anterior cruciate ligament (ACL) tears from mucoid degeneration.

Material and Methods:

Thirty-seven patients with complete ACL tears and 43 with ACL mucoid degeneration were included in this study. Discontinuity, the abnormal signal intensity of the ACL on fat-saturated-PD weighted images, contusions, a deep lateral femoral notch, anterior tibial translation, uncovered posterior horn of the lateral meniscus, a celery stalk appearance, thickening, ganglion cysts, intraosseous cysts, the ACL, Blumensaat, and posterior cruciate ligament (PCL) angles were evaluated. Optimum threshold values, sensitivity, specificity, and 95% CIs for the angles were calculated to predict the tear.

Results:

The prevalence of the significant findings in a tear versus mucoid degeneration, respectively, was as follows: discontinuity (97% vs. 0%, p < 0.001), contusions (65% vs. 2%, p < 0.001), the deep lateral femoral notch (22% vs. 0%, p = 0.001), anterior tibial translation (70% vs. 14%, p < 0.001), uncovered the lateral meniscus (46% vs. 7%, p < 0.001), a celery stalk appearance (0% vs. 66%, p < 0.001), thickening (19% vs. 100%, p < 0.001), ganglion cysts (14% vs. 70%, p < 0.001), and intraosseous cysts (8% vs. 63%, p < 0.001). Threshold values of ACL, Blumensaat, and PCL angles to predict the tear were ≤36° (78% sensitivity, 91% specificity), >11° (84%, 81%), and ≤96° (65%, 91%), respectively.

Conclusion:

A celery stalk appearance in the mucoid degeneration and discontinuity in an ACL tear are important in the differential diagnosis. ACL, Blumensaat, and PCL angles can be helpful in settings of diagnostic uncertainty.

Anterior Cruciate Ligament Ganglion Cyst and Mucoid Degeneration: A Review

Mucoid degeneration and ganglion cyst are two distinct non-traumatic lesions of the anterior cruciate ligament (ACL) that most commonly occur discretely but occasionally coexist. They are relatively uncommon, and their exact aetiopathogenesis is still not clear. ACL ganglion cyst occurs more frequently among relatively younger patients compared to mucoid degeneration. They could be asymptomatic and discovered incidentally while evaluating the knee for other pathologies. Symptomatic cases of the two conditions present with nonspecific chronic pain, painful limitation of terminal flexion and extension, and mechanical block (among other symptoms), similar to that of other internal derangement pathologies of the knee. Magnetic resonance imaging is the investigation of choice, and diagnostic criteria are defined. Arthroscopic management of these conditions efficiently provides an improvement in symptoms without instability. Computed tomography scan guided aspiration is also useful in selected cases of ACL ganglion cyst. ACL ganglion cyst and mucoid degeneration should be considered in the differential diagnosis of chronic knee pain and stiffness of unspecified etiology.

Intercondylar Ganglion Cyst with Mucoid Degeneration of Posterior Cruciate Ligament of Knee: Report of A Rare Case and Review of Literature

Introduction:

Mucoid degeneration and Ganglion cysts arising from the posterior cruciate ligament (PCL) of the knee are rare. The aetiology, clinical features and Magnetic resonance imaging (MRI) appearance of PCL mucoid degeneration and intercondylar ganglion cyst are discussed.

Case Report:

We present a 36 year-old male patient who presented with chronic right knee pain for the duration of 5-6 months. No evidence of ligament instability on clinical examination was found. A diagnosis of PCL mucoid degeneration and intercondylar ganglion cyst was made on MRI.

Conclusion:

Mucoid degeneration and ganglion cyst involving PCL are uncommon lesions and represents the spectrum of same pathology. MR imaging is sensitive, specific, accurate and noninvasive, while providing multiplanar imaging and superior identification of the anatomical and morphological relationship of the synovial tissue to the surrounding structures, an additional intra-articular lesions can also be detected.

Early reconstruction should be considered in younger patients with symptomatic mucoid degeneration of the anterior cruciate ligament

Background

Mucoid degeneration of the anterior cruciate ligament (ACL) is mostly observed in middle-aged patients with knee pain and limited range of motion. Although arthroscopic resection of the degenerated ACL is the treatment of choice following the failure of conservative management, the extent of the excision and subsequent ACL reconstruction for postoperative knee instability remains controversial.

Case reports

We present four cases of mucoid degeneration of the ACL in patients aged <40 years, and suggest a suitable treatment strategy for younger patients. All four patients (mean age, 33.8 years) were diagnosed with mucoid degeneration of the ACL based on characteristic clinical symptoms and magnetic resonance imaging. Arthroscopic resection of the affected portion of the ACL was performed as follows: partial resection in two cases with limited hypertrophy, and total ACL resection in the remaining two cases with degeneration involving the entire ligament. Preoperative symptoms disappeared in all cases after resection of the lesions. In the two patients with partial resection, the ACL was completely torn during subsequent sports activities despite showing no symptoms of instability for 2 years postoperatively. All four patients, including the two treated by total resection, underwent ACL reconstruction using an autogenous hamstring tendon.

Conclusion

Considering the rupture of residual ACL fibres after partial resection and the inevitability of total ACL resection due to degeneration of the entire ligament, ACL reconstruction should be considered in younger patients with symptomatic mucoid degeneration of the ACL.

Mucoid degeneration of the anterior cruciate ligament: Management and outcome

BACKGROUND

Mucoid degeneration (MD) is a rare pathological affection of the anterior cruciate ligament (ACL). Mucinous material within the substance of ACL produces pain and limited motion in the knee. This series describes the clinicoradiological presentation of patients with mucoid ACL, partial arthroscopic debridement of ACL and outcomes.

MATERIALS AND METHODS

During a period of 3 years, 11 patients were included based upon the clinical suspicion, magnetic resonance imaging (MRI) findings, arthroscopic features and histopathologic confirmation of MD of ACL.

RESULT

Six patients were male and five were female with median age of 40 years (range 21-59 years). All patients complained of knee pain with median duration of 5 months (range 1-24 months). All patients had painful deep flexion with 63.6% (N = 7) reporting trivial trauma before the onset of symptoms. MRI revealed MD of ACL in all with associated cyst in three patients. Partial debridement of ACL was done in ten and complete in one patient. None of them required notchplasty. Histopathology confirmed the diagnosis in all of them. At the mean followup of 13.81 months (range 6-28 months), all patients regained complete flexion and none complained of instability.

CONCLUSION

Prior knowledge of condition with high index of suspicion and careful interpretation of MRI can establish the diagnosis preoperatively. It responds well to partial debridement of ACL and mucinous material without development of instability.

Mucoid degeneration of the anterior cruciate ligament: a case report

We report a case of mucoid degeneration of the anterior cruciate ligament (ACL). Mucoid degeneration of the ACL is a very rare cause of knee pain. There have been only some reported cases of mucoid degeneration of the ACL in the English literature. We reviewed previous reports and summarized clinical features and symptoms, including those found in our case. Magnetic Resonance Imaging is the most useful tool for differentiating mucoid degeneration of the ACL from an intraligamentous ganglion or other lesions in the knee joint. If this disease is considered preoperatively, it can be diagnosed easily based on characteristic findings.

Prominent mucoid degeneration of the parotid gland in a patient with systemic lupus erythematosus

Lupus erythematosus (LE) can cause various cutaneous lesions including panniculitis (LE profundus), but salivary gland involvement has been extremely rare in patients with LE. Herein, we report the first documented case of systemic LE with prominent mucoid degeneration and lymphoplasmacytic infiltration in the parotid gland. A 38-year-old Japanese male with histories of autoimmune hemolytic anemia and systemic LE presented with a swelling of the bilateral cervical region. A physical examination revealed a swelling of the bilateral parotid gland and erythema of the right cheek. A biopsy specimen of the cheek demonstrated LE profundus with mucoid material deposition in the dermis. A biopsy specimen of the parotid gland showed lymphoplasmacytic infiltration and prominent mucoid material deposition within the parotid gland as well as mild lymphoplasmacytic infiltration and hyaline fat necrosis in the perisalivary tissue. Mucoid material deposition is one of the characteristic features of LE, however, this is the first case demonstrating mucoid material deposition in the salivary gland. Moreover, albeit extremely rare, lymphoplasmacytic infiltration within the lobules of the salivary gland has also been reported in patients with LE. Therefore, it is important that both lymphoplasmacytic infiltration and mucoid material deposition must be included in the differential diagnostic considerations for salivary gland tumors in patients who had been previously diagnosed as systemic or discoid LE.

Arthroscopic management of mucoid degeneration of anterior cruciate ligament

BACKGROUND

Mucoid degeneration of the anterior cruciate ligament (ACL) is a less understood entity. The purpose of this study was to diagnose mucoid degeneration of anterior cruciate ligament and to assess the effectiveness of arthroscopic treatment in these patients.

MATERIALS AND METHODS

Between December 2007 and November 2011, 20 patients were diagnosed to be suffering from mucoid degeneration of anterior cruciate ligament (ACL) on the basis of magnetic resonance imaging (MRI), histopathology, and arthroscopy findings. 12 patients were males and 8 patients were females, with mean age of 42.2 years for males (range 28-52 years) and 39.4 years for females (range 30-54 years). They presented with pain on terminal extension (n=10) and on terminal flexion (n=2) without history of significant preceding trauma. MRI showed an increased signal in the substance of the ACL both in the T1- and T2-weighted images, with a mass-like configuration that was reported as a partial or complete tear of the ACL by the radiologist. At arthroscopy, the ACL was homogenous, bulbous, hypertrophied, and taut, occupying the entire intercondylar notch. A debulking of the ACL was performed by a judicious excision of the degenerated mucoid tissue, taking care to leave behind as much of the intact ACL as possible. Releasing it and performing a notchplasty treated impingement of the ACL to the roof and lateral wall. In one patient, we had to replace ACL due to insufficient tissue left behind to support the knee.

RESULTS

Good to excellent pain relief on terminal flexion-extension was obtained in 19 of 20 knees. The extension deficit was normalized in all knees. Lachman and anterior drawer test showed a firm endpoint in all, and 85% (n=17) showed good to excellent subjective satisfaction.

CONCLUSIONS

Mucoid hypertrophy of the ACL should be suspected in elderly persons presenting pain on terminal extension or flexion without preceding trauma, especially when there is no associated meniscal lesion or ligamentous insufficiency. They respond well to a judicious arthroscopic release of the ACL with notchplasty.