Imaging ACL reconstructions and their complications

A tight anterosuperior intercondylar notch may increase the risk of cyclops syndrome after anterior cruciate ligament reconstruction using a quadruple semi-tendinosus short autograft

BACKGROUND

Cyclops syndrome is loss of terminal knee extension caused by a fibrous nodule developed in the anterior intercondylar notch. The many known risk factors include preoperative motion-range limitation, tibial tunnel malposition, and tight hamstrings. The primary objective of this study was to assess whether intercondylar notch size was associated with the risk of cyclops syndrome or graft tear after anterior cruciate ligament (ACL) reconstruction using a quadruple semi-tendinosis autograft. The secondary objective was to determine whether intercondylar notch size was associated with functional outcomes.

HYPOTHESIS

A narrow intercondylar notch is associated with higher risks of cyclops syndrome and poor functional outcomes.

METHODS

Consecutive patients who underwent ACL reconstruction by quadruple semi-tendinosus autograft were included retrospectively. Preoperative magnetic resonance imaging scans were assessed by a single senior surgeon, who determined the conventional notch width index (NWI) and the anterior NWI (aNWI) for each patient.

RESULTS

The 120 included patients had a mean follow-up of 2.4±0.8 years. Among them, 20 (16.7%) experienced cyclops syndrome and 7 (5.8%) graft rupture. At last follow-up, 26 (21.7%) had not returned to sports and only 47 (39.2%) had returned to sports at the pre-injury level. The mean Lysholm score was 87.9±13.5 and the main subjective IKDC score was 84±13. A narrow notch was significantly associated with lower likelihoods of returning to sports (p=0.001), returning to the same sport (p<0.0001), and returning to the pre-injury sport level (p=0.004). By multivariate analysis, only the aNWI index was significantly associated with the risk of cyclops syndrome (p<0.0001). An aNWI index lower than 0.18 had 85% sensitivity and 78% specificity for predicting cyclops syndrome.

CONCLUSION

A narrow anterosuperior intercondylar notch may increase the risk of cyclops syndrome after ACL reconstruction using a quadruple semi-tendinosus graft but is not associated with the risk of graft rupture.

LEVEL OF EVIDENCE

IV, retrospective observational cohort study.

To achieve the unachievable-Patients' experiences of opting for delayed anterior cruciate ligament reconstruction after trying rehabilitation alone as primary treatment: A qualitative study

INTRODUCTION

About 50% of patients who sustain an anterior cruciate ligament (ACL) injury are treated without ACL reconstruction (ACL-R). A significant proportion of these patients opt for late ACL-R. Patients' experience of changing treatment has not yet been investigated and presented in the scientific literature.

AIM

To explore patients' experiences before and after changing treatment from ACL rehabilitation alone to ACL-R.

METHOD

Fifteen patients were interviewed in semi-structured interviews, which were recorded, transcribed, and analyzed with qualitative content analysis, based on the method described by Graneheim and Lundman. Patients were between 26 and 58 years old, and had tried rehabilitation for a minimum of 9 months prior to ACL-R.

RESULTS

Two themes, "Expecting what could not be achieved: the struggle to recover and not becoming stable", and "Internal completeness: expectations can be achieved", emerged from the analysis. Each theme was supported by three main categories and 5-6 subcategories. The first theme represents the journey before ACL-R, where patients experienced getting stronger, but perceived the knee as unstable. The second theme represents the journey after ACL-R, where patients expressed that they felt whole after their ACL-R, and where able to achieve their expections. Patients experienced a greater support from the healthcare system, and ultimately expressed a feeling of having achieved the unachievable after ACL-R.

SUMMARY

Patients who cross over from ACL rehabilitation to ACL-R experienced rehabilitation alone as insufficient to achieve the desired outcomes, which resulted in a need to opt for delayed ACL-R. Healthcare providers need to support patients, who primarily choose to undergo rehabilitation alone and later opt for ACL-R, throughout the whole rehabilitation process.

Recurrent cyclops lesion after primary anterior cruciate ligament reconstruction using bone tendon bone allograft: A case report

BACKGROUND

Cyclops lesions are a known complication of anterior cruciate ligament (ACL) reconstruction, with symptomatic cyclops syndrome occurring in up to 11% of surgeries. Recurrent cyclops lesions have been rarely documented; this case study documents the successful treatment of a recurrent cyclops lesion.

CASE SUMMARY

A 28-year-old female presented following a non-contact injury to the right knee. Workup and clinical exam revealed an ACL tear, and arthroscopic reconstruction was performed. Two years later a cyclops lesion was discovered and removed via arthroscopic synovectomy. Seven months postoperatively, the patient presented with pain, stiffness, and difficulty achieving terminal extension. A smaller recurrent cyclops lesion was diagnosed, and a repeat synovectomy was performed. The patient recovered fully.

CONCLUSION

To the best of our knowledge, this is the first documented case of recurrent cyclops lesion after bone-patellar tendon-bone allograft ACL reconstruction presenting as cyclops syndrome.

The use of slice encoding for metal artifact correction (SEMAC) sequencing improves the diagnostic evaluation of graft integrity following anterior cruciate ligament reconstruction

OBJECTIVES

To determine whether magnetic resonance imaging (MRI) with metal artifact reduction sequencing is superior to conventional knee MRI in the evaluation of an injured anterior cruciate ligament (ACL) graft, where visualisation on conventional MRI can be limited by the metal artifact from fixation devices.

METHODS

Eighteen patients underwent conventional MRI sequence (proton density fat saturated [PDFS]) and two types of metal artifact reduction sequencing MRI (WARP, slice encoding for metal artifact correction (SEMAC); Siemens) following a secondary injury to their ACL reconstructed knee. Six raters with experience in knee MRI evaluation reviewed sagittal PDFS, WARP, and SEMAC sequences, providing semi-quantitative grades for visualisation and diagnostic confidence assessing the ACL, posterior cruciate ligament , menisci, tibial and femoral tunnel margins, and articular cartilage. Intra-class correlation coefficients for inter-rater reliability were evaluated. The 6-rater mean scores for the visualisation and diagnostic confidence derived from each sequence were compared using the Friedman test for multiple paired samples.

RESULTS

No statistically significant difference in the ACL visualisation among the sequences was found (p ​= ​0.193). Further, a subgroup analysis was performed in cases evaluated as "moderately blurry" or "indistinct ACL visualisation" on PDFS (58% of cases). SEMAC significantly improved diagnostic confidence in ACL visualisation (p ​= ​0.041) and ACL graft rupture (p ​= ​0.044) compared to PDFS. There was no statistically significant difference in the inter-observer reliability between sequences. The WARP sequence added 2.84 ​± ​0.69 ​min, while SEMAC added 2.95 ​± ​0.40 ​min to the standard knee MRI scan time.

CONCLUSION

use of the SEMAC metal reduction sequence significantly improved diagnostic accuracy and confidence in the detection of ACL graft rupture in cases where the ACL was moderately blurry or indistinct on the PDFS sequence. This sequence should be considered as an adjunct to conventional PDFS in cases where graft visualisation is limited by the metal artifact from fixation devices.

LEVEL OF EVIDENCE

III.

Intra-femoral tunnel graft lengths less than 20 mm do not predispose to early graft failure, inferior outcomes or poor function. A prospective clinico-radiological comparative study

PURPOSE

Increasing demands on skills with mounting pressures from expectations from arthroscopic anterior cruciate ligament (ACL) reconstructions requires precise knowledge of technical details by surgeons. One such element is the minimum length of graft in femoral tunnel to allow for adequate tendon-to-bone healing and early return to activities and sports. This has, however, remained an unanswered question.

PURPOSE

To study and compare clinico-radiological outcomes of ACL reconstructions in patients with < 20 mm of intra-femoral tunnel graft length with those measuring ≥ 20 mm.

METHODS

All eligible patients undergoing arthroscopic ACL reconstruction were sequentially divided into two groups based on the intra-femoral tunnel graft lengths (A: < 20 mm, n = 27; and B: ≥ 20 mm, n = 25). Exclusions were made for those > 45 years of age, with chondral and/or multi-ligamentous injuries and with systemic pathologies. All patients were postoperatively evaluated in clinics by physical examination and functional scoring (Lysholm and modified Cincinnati scores) at 3, 6 and 12-month intervals. Graft vascularity was assessed by signal-to-noise quotient ratio (SNQR) using magnetic resonance imaging (MRI) at 3 and 12 months.

RESULTS

No significant differences were noted in mean Lysholm and modified Cincinnati scores between the two groups at the end of 1 year. There were also no significant differences in graft maturation over time and SNQR at 3 and 12 months in the region of interest (ROI).

CONCLUSIONS

Intra-femoral tunnel graft length of less than 20 mm does not compromise early clinical and functional outcomes of ACL reconstructions.

Anterior cruciate ligament reconstruction related complications: 2D and 3D high-resolution magnetic resonance imaging evaluation

Anterior cruciate ligament (ACL) injury is a common indication for sports-related major surgery and accounts for a large proportion of ligamentous injuries in athletes. The advancements in 2D and 3D MR imaging have provided considerable potential for a one-stop shop radiation-free assessment with an all-in-one modality examination of the knee, for both soft-tissue and bone evaluations. This article reviews ACL injuries and types of surgical managements with illustrative examples using high resolution 2D and 3D MR imaging. Various complications of ACL reconstruction procedures are highlighted with a focus on the use of advanced MR imaging and relevant arthroscopic correlations.

Femoral intercondylar notch: Accuracy of a novel MRI measurement protocol

OBJECTIVE

The most common mechanical complication following an anterior cruciate ligament (ACL) reconstruction is joint stiffness, due in part to cyclops syndrome. A narrow intercondylar notch is an anatomical risk factor. A reliable preoperative notch measurement would help anticipate proper graft size, or plan a notchplasty during the ligament reconstruction, if necessary. No study has yet assessed the accuracy of the methods used to measure notch size.

HYPOTHESIS

The novel measurement protocol proposed in this study would be more reproducible than the reference technique.

METHODS

A total of 20 preoperative knee MRIs performed during the assessment of an ACL rupture were randomly selected. The notch size was measured using 2 methods: traditional (ratio of the notch and metaphyseal widths measured on a line drawn through the popliteal groove) and novel. The latter was measured using the same ratio but took into account the notch width in its proximal third, according to a coronal slice that passes through the ACL tibial attachment. Three orthopedic surgeons with different levels of experience (senior surgeon, junior surgeon and surgical resident) performed these measurement protocols twice on anonymized MRI scans, 10days apart. Spearman's rank correlation coefficient was used to assess the intraobserver correlations and a concordance index was used to assess the interobserver correlations. The influence of the second MRI reading was analyzed with a bootstrap test.

RESULTS

The mean intraobserver reliability was 0.73 for the reference method and 0.83 for the proposed method. The values of the bootstrap tests were higher for the proposed method (0.45 vs. 0.45 and 0.70; p<05 for interobserver; 0.49 vs. 0.69 and 0.62; p<05 for intraobserver).

CONCLUSION

The proposed measurement protocol showed a higher reproducibility in assessing notch size than the traditional method. This technique therefore provides a reliable assessment of the intercondylar notch width.

LEVEL OF EVIDENCE

IV; retrospective study.

Comparison of mechanical properties in interference screw fixation technique and organic anterior cruciate ligament reconstruction method: a biomechanical study

BACKGROUND

Bone and Site Hold Tendon Inside (BASHTI) technique is an organic implant-less technique for anterior cruciate ligament (ACL) reconstruction with some clinical advantages, such as speeding up the healing process, over implantable techniques. The study aims to compare the mechanical properties of BASHTI technique with the conventional interference screw technique.

METHODS

To investigate the mechanical properties, 20 in-vitro experimental tests were conducted. Synthetic dummy bone, along with fresh digital bovine tendons, as a graft, were used for experiments. Three loading steps were applied to all specimens, including a preconditioning, a main cyclic, and a pull-out loading.

RESULTS

The mechanical characters of an interference screw technique using an 8 mm tendon diameter, including fixation strength, average cyclic stiffness (ACS), and average pull-out stiffness (APS) were found to be 439 ± 132 N, 10.3 ± 5.3 kN/mm, and 109 ± 40 N/mm, respectively. In the case of an interference screw using a 9 mm tendon, the fixation strength, ACS, and APS were obtained 549 ± 87 N, 10.3 ± 4.7 kN/mm, and 91 ± 13 N/mm, respectively. In parallel, the fixation strength, APS, and ACS of BASHTI technique using an 8 mm tendon were 360 ± 123 N, 3.3 ± 0.6 kN/mm, and 79 ± 27 N/mm, respectively, while, for 9 mm tendon 278 ± 103 N, 2.4 ± 1.2 kN/mm, and 111 ± 40 N/mm, were reported for fixation strength, APS, and ACS respectively when BASHTI technique was used.

CONCLUSION

About 50% of interference screw samples showed superior mechanical properties compared to BASHTI technique, but in another half of the samples, the differences were not significant (N.S.). However, due to organic advantages of BASHTI technique and lower cost, it could be used as a substitute for interference screw technique, especially where fast recovery is expected.

Graft-Preserving Arthroscopic Debridement With Hardware Removal Is Effective for Septic Arthritis After Anterior Cruciate Ligament Reconstruction: A Clinical, Arthrometric, and Magnetic Resonance Imaging Evaluation

BACKGROUND

Arthroscopic debridement with graft preservation has been advocated as the treatment of choice for septic arthritis after anterior cruciate ligament (ACL) reconstruction, but no previous studies have investigated if hardware removal, while retaining the graft in situ, improves the success rate. Moreover, it is unclear whether the premature removal of fixation devices may affect graft integration and knee stability.

PURPOSE/HYPOTHESIS

The purpose was to assess the clinical and functional outcomes of patients with septic arthritis after ACL reconstruction who underwent arthroscopic debridement, while retaining the graft in situ but removing fixation devices, and to determine if premature hardware removal affects graft integrity and function. The hypothesis was that arthroscopic debridement with hardware removal would be effective in eradicating infections while not compromising graft integration and function.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

From a cohort of 2384 cases of arthroscopic ACL reconstruction, 24 patients with postoperative septic arthritis were included for the analysis; 18 patients were available for a clinical evaluation using the International Knee Documentation Committee (IKDC) form, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lysholm score, and Tegner score at a minimum 12-month follow-up. Knee laxity was assessed clinically with standardized manual laxity tests and instrumentally using an arthrometer and a triaxial accelerometer. Additionally, 3-T magnetic resonance imaging (MRI) at final follow-up was performed, focusing on the graft signal, the cartilage status, and the occurrence of arthrofibrosis.

RESULTS

Eradication of the infection was achieved in all cases, and only 1 graft removal was performed because of insufficient tension. Among the remaining 23 patients, a single arthroscopic debridement procedure with hardware removal while preserving the graft was effective in 21 cases (91%) at a mean of 30 ± 37 days from ACL reconstruction to debridement. At last follow-up, 2 patients required a further ACL revision procedure. The mean IKDC, WOMAC, Lysholm, and Tegner scores of the patients available for the clinical evaluation were 75 ± 19, 90 ± 8, 79 ± 21, and 6 ± 2, respectively. No abnormal laxity was reported on manual testing, and arthrometric and accelerometer tests also demonstrated good knee stability (mean KT-1000 arthrometer side-to-side difference was 1.6 ± 1.2 mm at manual maximum force). On MRI, a good graft signal was found in 50% of cases, while concomitant signs of arthrofibrosis were detected in 81% of patients. Severe cartilage defects (International Cartilage Repair Society grade ≥3) were reported in 63% of cases.

CONCLUSION

Arthroscopic debridement with hardware removal was effective in the eradication of infections after ACL reconstruction with extra-articular fixation while preserving graft integrity without compromising knee stability. Patients and surgeons should be aware of complications that might affect the outcome, particularly arthrofibrosis and chondrolysis.

All-Inside Quadrupled Semitendinosus Autograft Shows Stability Equivalent to Patellar Tendon Autograft Anterior Cruciate Ligament Reconstruction: Randomized Controlled Trial in Athletes 24 Years or Younger

PURPOSE

To compare clinical outcomes of knee anterior cruciate ligament (ACL) autograft reconstruction using all-inside quadrupled semitendinosus (AIST) versus bone-patellar tendon-bone (BPTB) in a high-risk athletic population 24 years or younger.

METHODS

Skeletally mature candidates younger than 24 years old with an ACL tear were randomized into either the AIST (n = 32) or BPTB (n = 32) group and were followed for 2 years. Magnetic resonance imaging scans were obtained at 1-year follow-up, and radiographs were obtained at 2-year follow-up. All surgeries were performed by a single surgeon using an anteromedial portal to establish the femoral tunnel. The primary outcome measure was KT-1000 stability testing. Secondary outcome measures included International Knee Documentation Committee (IKDC) Knee Evaluation Form, IKDC Subjective Form, Knee Injury and Osteoarthritis Outcome Score, Marx Activity Scale, visual analog pain scale, and SF-12 (Mental and Physical).

RESULTS

At 2-year follow-up, no statistical difference existed with KT-1000-measured side-to-side laxity between AIST (0.3 ± 0.7 mm, 95% confidence interval 0.0-1.0 mm) and BPTB (0.0 ± 0.8 mm, confidence interval CI -0.3 to 1.1 mm) (P = .197). In addition, no statistical differences between the groups were found for IKDC Subjective Form, Knee Injury and Osteoarthritis Outcome Score, Marx, SF-12 Mental, SF-12 Physical, or with regards to imaging findings. Patients with BPTB reported significantly greater postoperative pain scores at days 2 (P = .049), 3 (P = .004), and 7 (P = .015) and had significantly greater kneeling pain at 2 years (P < .019). A return to sport questionnaire at 2 years revealed no significant difference between the groups for returning to preoperative level of sport activity (83% AIST, 74% BPTB; P = .415). Two graft retears (7%; P = .222) occurred in the AIST group. Three patients in the BPTB group experienced ACL tears in the contralateral knee (9%; P = .239).

CONCLUSIONS

ACL reconstruction with an all-inside quadrupled semitendinosus autograft construct is equivalent to patellar BPTB autograft based on KT-1000 stability testing in athletes 24 years or younger.

LEVEL OF EVIDENCE

randomized controlled trial with 92% 2-year follow-up, Level I.

Midterm Outcomes of Arthroscopic Reduction and Internal Fixation of Anterior Cruciate Ligament Tibial Eminence Avulsion Fractures With K-Wire Fixation

PURPOSE

To determine the clinical and radiological outcomes of patients who underwent arthroscopic reduction and internal fixation of a tibial eminence avulsion fracture with Kirshner wires (K-wires) at a mean of 8 years following surgery.

METHODS

This was a retrospective study with prospectively collected data. Inclusion criteria consisted of patients who underwent arthroscopic reduction and internal fixation of tibial eminence fracture with K-wires between 1989 and 2015 at a minimum of 18 months follow-up. Assessment included the International Knee Documentation Committee Ligament Evaluation, Lysholm Knee Score, and clinical outcomes. Magnetic resonance imaging (MRI) was performed to evaluate the anterior cruciate ligament (ACL) and evidence of osteoarthritis.

RESULTS

A total of 48 participants met the inclusion criteria, and 32 were reviewed at a mean of 8 years (range, 18-260 months) after surgery. The mean age at the time of surgery was 24.5 years (10-55 years). Subsequent ACL injury occurred in 5 participants (10.4%) on the index knee and in 1 participant also on the contralateral knee; 86% had a normal examination, and no patients had >5-mm side-to-side difference on instrumented testing. The mean International Knee Documentation Committee subjective score at 8 years was 86 (range, 40-100). On MRI scan assessment for osteoarthritic changes at final follow-up, 82% of participants had no evidence of chondral wear on the medial compartment and 73% had no changes in the lateral compartment according to Magnetic Resonance Image Osteoarthritis Knee Score classification. On MRI scan qualitative assessment of ACL and tibial eminence, 7 participants (32%) were found to have high signal at the fracture site. The mean medial tibial eminence height was 9.2 mm (range, 6.3 mm to 1.31 cm) and the lateral tibial eminence height was an average of 6.7 mm (range, 0.38-0.97 mm). Significant kneeling pain was reported by 8 participants (25%).

CONCLUSIONS

This study indicates that internal fixation with K-wires is an acceptable approach to reduce tibial eminence avulsion fractures, providing excellent clinical and radiological outcomes at a minimum of 18 months of follow-up.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Anterior cruciate ligament reconstruction: MR imaging findings

More than two million people tear their anterior cruciate ligament (ACL) each year, and ACL reconstruction occupies a significant proportion of everyday orthopedic practice, being one of the most commonly performed sports medicine surgical procedures. Patients with postoperative symptoms are frequently imaged to monitor ligament grafts and to identify complications. Given the number of patients undergoing ACL reconstruction, knowledge of the potential complications of this surgery is essential for radiologists. This article provides a review of imaging of ACL reconstruction procedures and the potential complications specific to this surgery.

Magnetic resonance imaging after anterior cruciate ligament reconstruction: A practical guide

Anterior cruciate ligament (ACL) reconstruction is one of the most common orthopedic procedures performed worldwide. In this regard, magnetic resonance imaging (MRI) represents a useful pre-operative tool to confirm a disruption of the ACL and to assess for potential associated injuries. However, MRI is also valuable post-operatively, as it is able to identify, in a non-invasive way, a number of aspects and situations that could suggest potential problems to clinicians. Graft signal and integrity, correct tunnel placement, tunnel widening, and problems with fixation devices or the donor site could all compromise the surgical outcomes and potentially predict the failure of the ACL reconstruction. Furthermore, several anatomical features of the knee could be associated to worst outcomes or higher risk of failure. This review provides a practical guide for the clinician to evaluate the post-surgical ACL through MRI, and to analyze all the parameters and features directly or indirectly related to ACL reconstruction, in order to assess for normal or pathologic conditions.