Valgus malalignment causes increased forces on a medial collateral ligament reconstruction under dynamic valgus loading: A biomechanical study.

PURPOSE: To investigate the forces on a medial collateral ligament (MCL) reconstruction (MCLR) relative to the valgus alignment of the knee. METHODS: Eight fresh-frozen human cadaveric knees were subjected to dynamic valgus loading at 400 N using a custom-made kinematics rig. After resection of the superficial medial collateral ligament, a single-bundle MCLR with a hamstring tendon autograft was performed. A medial opening wedge distal femoral osteotomy was performed and fixed with an external fixator to gradually adjust the alignment in 5° increments from 0° to 10° valgus. For each degree of valgus deformity, the resulting forces acting on the MCLR were measured through a force sensor and captured in 15° increments from 0° to 60° of knee flexion. RESULTS: Irrespective of the degree of knee flexion, increasing valgus malalignment resulted in significantly increased forces acting on the MCLR compared to neutral alignment (p < 0.05). Dynamic loading at 5° valgus resulted in increased forces on the MCLR at all flexion angles ranging between 16.2 N and 18.5 N (p < 0.05 from 0° to 30°; p < 0.01 from 45° to 60°). A 10° valgus malalignment further increased the forces on the MCLR at all flexion angles ranging between 29.4 N and 40.0 N (p < 0.01 from 0° to 45°, p < 0.05 at 60°). CONCLUSION: Valgus malalignment of the knee caused increased forces acting on the reconstructed MCL. In cases of chronic medial instabilities accompanied by a valgus deformity ≥ 5°, a realigning osteotomy should be considered concomitantly to the MCLR to protect the graft and potentially reduce graft failures. LEVEL OF EVIDENCE: Level III.

The pie-crusting release of the medial collateral ligament in arthroscopic partial meniscectomy is associated with improved clinical outcomes without altering radiological measurements.

PURPOSE: The aim of this study was to evaluate how the pie-crusting technique affects clinical and radiological outcomes in patients undergoing arthroscopic partial meniscectomy. METHODS: A total of 68 patients with Kellgren-Lawrence (K-L) grade 2 who underwent arthroscopic partial meniscectomy between 2015 and 2021 were evaluated and divided into two groups as arthroscopic partial meniscectomy (36 patients) and arthroscopic partial meniscectomy with pie-crusting (32 patients) according to whether the pie-crusting technique was applied or not. All patients were evaluated at a minimum 2-year follow-up in terms of Lysholm score, Tegner activity score, International Knee Documentation Committee (IKDC) score and Visual Analogue Scale (VAS) score. To assess the impact of the pie-crusting technique, radiological measurements were conducted using radiographs taken before and after pie-crusting, as well as postoperative radiographs. RESULTS: Lysholm, Tegner, IKDC and VAS scores exhibited statistically significant differences after surgery compared to preoperative evaluations in both groups (p < 0.05). Furthermore, these scores were significantly superior in the arthroscopic partial meniscectomy with pie-crusting group compared to the arthroscopic partial meniscectomy group at 24 months postoperatively (p < 0.05). While the radiological measurements in the arthroscopic partial meniscectomy with pie-crusting group showed statistically significant differences before and after pie-crusting (p < 0.05), no significant difference was observed between before pie-crusting and 12 and 24 months postoperatively (n.s.). CONCLUSION: The current study is the first to demonstrate the true effectiveness of the pie-crusting technique. The application of the pie-crusting technique when necessary results in a statistically significant improvement in clinical scores without affecting radiological measurements for patients undergoing arthroscopic partial meniscectomy compared to not utilising it. LEVEL OF EVIDENCE: Level III.

Isometry of anteromedial reconstructions mimicking the deep medial collateral ligament depends on the femoral insertion.

PURPOSE: This study aimed to investigate the length change patterns of the native deep medial collateral ligament (dMCL) and potential anteromedial reconstructions (AMs) that might be added to a reconstruction of the superficial MCL (sMCL) to better understand the control of anteromedial rotatory instability (AMRI). METHODS: Insertion points of the dMCL and potential AM reconstructions were marked with pins (tibial) and eyelets (femoral) in 11 cadaveric knee specimens. Length changes between the pins and eyelets were then tested using threads in a validated kinematics rig with muscle loading of the quadriceps and iliotibial tract. Between 0° and 100° knee flexion, length change pattern of the anterior, middle and posterior part of the dMCL and simulated AM reconstructions were analysed using a rotary encoder. Isometry was tested using the total strain range (TSR). RESULTS: The tibiofemoral distance of the anterior dMCL part lengthened with flexion (+12.7% at 100°), whereas the posterior part slackened with flexion (-12.9% at 100°). The middle part behaved almost isometrically (maximum length: +2.8% at 100°). Depending on the femoral position within the sMCL footprint, AM reconstructions resulted in an increase in length as the knee flexed when a more centred position was used, irrespective of the tibial attachment position. Femoral positioning in the posterior aspect of the sMCL footprint exhibited <4% length change and was slightly less tight in flexion (min TSR = 3.6 ± 1.5%), irrespective of the tibial attachment position. CONCLUSION: The length change behaviour of potential AM reconstructions in a functionally intact knee is mainly influenced by the position of the femoral attachment, with different tibial attachments having a minimal effect on length change. Surgeons performing AM reconstructions to control AMRI would be advised to choose a femoral graft position in the posterior part of the native sMCL attachment to optimise graft length change behaviour. Given the high frequency of MCL injuries, sufficient restoration of AMRI is essential in isolated and combined ligamentous knee injuries. LEVEL OF EVIDENCE: There is no level of evidence as this study was an experimental laboratory study.

Release or transection of superficial medial collateral ligament during open-wedge high tibial osteotomy demonstrated similar clinical outcomes and valgus laxity.

PURPOSE: To analyse whether valgus laxity and clinical outcomes differ depending on whether the superficial medial collateral ligament (sMCL) is released or transected during medial open-wedge high tibial osteotomy (MOWHTO). METHODS: Consecutive patients who underwent MOWHTO and subsequent radiological follow-up for at least 2 years were retrospectively evaluated. The patients were divided into release and transection groups, according to the sMCL manipulation technique. Each patient was assessed for the following variables on valgus stress radiographs taken before surgery and at the 12- and 24-month follow-ups: the absolute value of valgus (ABV) and side-to-side difference (SSD) between the affected and normal sides. The differences between preoperative SSD and those at 12 and 24 months were respectively calculated and defined as delta SSD (ΔSSD). The Visual Analogue Scale, Lysholm knee, International Knee Documentation Committee subjective, and Knee Injury and Osteoarthritis Outcome scores were used to evaluate patient-reported outcomes. RESULTS: Eighty-five patients were included in the study. Forty-two patients (49.6%) underwent sMCL release, and the remaining 43 patients (50.4%) underwent sMCL transection. No significant differences were observed in the ABV and SSD of valgus laxity at the different time points between the two groups (n.s.). Furthermore, no significant differences were observed in the ΔSSD at the 12- and 24-month follow-ups between the two groups (n.s.). Significant improvement from preoperative values was observed in all patient-reported outcomes (p < 0.001), with no significant differences between the two groups at any time point (n.s.). CONCLUSION: Significant improvements in clinical outcomes were observed, regardless of the technique used. Postoperative valgus laxity did not occur with either technique. The transection technique, which can be performed more simply and quickly, demonstrated similar clinical outcomes and valgus laxity to the release technique. LEVEL OF EVIDENCE: Level III.

Collateral ligament strain is linearly related to coronal lower limb alignment: A biomechanical study.

PURPOSE: The purpose of this study was to analyse the influence of coronal lower limb alignment on collateral ligament strain. METHODS: Twelve fresh-frozen human cadaveric knees were used. Long-leg standing radiographs were obtained to assess lower limb alignment. Specimens were axially loaded in a custom-made kinematics rig with 200 and 400 N, and dynamic varus/valgus angulation was simulated in 0°, 30°, and 60° of knee flexion. The changes in varus/valgus angulation and strain within different fibre regions of the collateral ligaments were captured using a three-dimensional optical measuring system to examine the axis-dependent strain behaviour of the superficial medial collateral ligament (sMCL) and lateral collateral ligament (LCL) at intervals of 2°. RESULTS: The LCL and sMCL were exposed to the highest strain values at full extension (p < 0.001). Regardless of flexion angle and extent of axial loading, the ligament strain showed a strong and linear association with varus (all Pearson's r ≥ 0.98; p < 0.001) and valgus angulation (all Pearson's r ≥ -0.97; p < 0.01). At full extension and 400 N of axial loading, the anterior and posterior LCL fibres exceeded 4% ligament strain at 3.9° and 4.0° of varus, while the sMCL showed corresponding strain values of more than 4% at a valgus angle of 6.8°, 5.4° and 4.9° for its anterior, middle and posterior fibres, respectively. CONCLUSION: The strain within the native LCL and sMCL was linearly related to coronal lower limb alignment. Strain levels associated with potential ultrastructural damages to the ligaments of more than 4% were observed at 4° of varus and about 5° of valgus malalignment, respectively. When reconstructing the collateral ligaments, an additional realigning osteotomy should be considered in cases of chronic instability with a coronal malalignment exceeding 4°-5° to protect the graft and potentially reduce failures. LEVEL OF EVIDENCE: There is no level of evidence as this study was an experimental laboratory study.

Ligament augmentation and reconstruction system (LARS) synthetic grafts are safe and effective for medial collateral ligament and posterolateral corner reconstructions in elite athletes.

PURPOSE: This study documents the efficacy and safety of using a Ligament Augmentation and Reconstruction System (LARS) ligament graft to augment extra-articular knee ligament reconstructions in elite athletes by reporting return-to-play (RTP) rates and levels, career longevity and complications. METHODS: A consecutive series of all extra-articular knee ligament reconstructions augmented by LARS ligaments in elite athletes undertaken by three specialist sports knee surgeons between 2013 and 2020 were reviewed. Seventy-six elite athletes, aged over 16 years old, and more than 2 years postsurgery were included. RTP was defined as competing at professional level or national/international level in amateur sport. RESULTS: There were 64 medial collateral ligament (MCL) and 12 posterolateral corner (PLC) reconstructions. Fifty-two (68.4%) underwent concomitant autograft cruciate ligament(s) reconstruction. The mean age was 25.1 years (SD ± 4.5). Most were football (35, 46.1%) or rugby players (35, 46.1%). Sixty-seven athletes (88.2%) RTP with 65 (97.0%) of these playing at the same or higher Tegner level. Fifty-six (83.6%) of the athletes that RTP were still playing at 2 years postsurgery. Twenty (57.1%) of those who had RTP and were more than 5 years postsurgery were still playing at 5 years. Six (7.9%) players required further surgery relating to the LARS/metalwork. One case had soft tissue inflammation adjacent to the proximal end of the synthetic graft, but it is unknown if this was mechanical irritation or a biological reaction. One MCL reruptured 4 years after RTP. CONCLUSION: Utilising LARS to augment extra-articular knee ligament reconstructions allows 88.2% of athletes with a variety of knee ligament injuries to return to elite sport. The low morbidity rates coupled with 57% of athletes still playing 5 years postsurgery demonstrates that the LARS is safe and effective in these cases. Although there are reports of LARS ligaments being used in MCL and PLC reconstructions, there is very little evidence investigating if they are safe and effective. This study demonstrates that LARS synthetic grafts can be safely used for MCL and PLC reconstructions in elite athletes and they permit a high RTP with a low risk of complications. LEVEL OF EVIDENCE: Level IV.

A rare case report of tenosynovial chondromatosis of the semimembranosus-medial collateral ligament bursa.

BACKGROUND: Synovial chondromatosis is an uncommon metaplastic process of the synovial lining that results in the formation of cartilaginous nodules within joints or their associated bursae or tendon sheaths. Radiologic evidence of mineralized bodies within these structures is typically pathognomonic for this condition. Extraarticular chondromatosis is rarer than intraarticular chondromatosis, and the knee is affected less frequently than the smaller joints of the hands and feet. To our knowledge, no reports describing this condition in the semimembranosus-medial collateral ligament (SM-MCL) bursa have been published. CASE PRESENTATION: We describe a case of tenosynovial chondromatosis in a 37-year-old woman. The case was atypical for both the location within the SM-MCL bursa and the paucity of radiodense or hypointense changes to support a clinical suspicion of chondroid metaplasia on radiographs and T2-weighted MRI, respectively. Recreational weightlifting and swimming by the patient were impaired by chronic pain, and restricted range of motion of the ipsilateral knee persisted despite extensive skilled physical therapy and injections of both corticosteroids and platelet-rich plasma. Thirteen months after a diagnostic and therapeutic knee arthroscopy, open surgical excision of the SM-MCL bursal body was performed, and knee pain and range of motion improved by the 6-week postoperative reevaluation. Pathologic evaluation of the excised tissue was consistent with tenosynovial chondromatosis. CONCLUSIONS: Synovial chondromatosis should be considered in the differential diagnosis for recalcitrant bursitis, even in the absence of classic imaging findings.

The anterior cruciate ligament injury severity scale (ACLISS) is an effective tool to document and categorize the magnitude of associated tissue damage in knees after primary ACL injury and reconstruction.

PURPOSE: To develop a tool allowing to classify the magnitude of structural tissue damage occurring in ACL injured knees. The proposed ACL Injury Severity Scale (ACLISS) would provide an easy description and categorization of the wide spectrum of injuries in patients undergoing primary ACL reconstruction, reaching from isolated ACL tears to ACL injuries with a complex association of combined structural damage. METHODS: A stepwise approach was used to develop the ACLISS. The eligibility of each item was based on a literature search and a consensus between the authors after considering the diagnostic modalities and clinical importance of associated injuries to the menisci, subchondral bone, articular cartilage or collateral ligaments. Then, a retrospective analysis of associated injuries was performed in 100 patients who underwent a primary ACL reconstruction (ACLR) by a single surgeon. This was based on acute preoperative MRI (within 8 weeks after injury) as well as intraoperative arthroscopic findings. Depending on their prevalence, the number of selected items was reduced. Finally, an analysis of the overall scale distribution was performed to classify the patients according to different injury profiles. RESULTS: A final scoring system of 12 points was developed (12 = highest severity). Six points were attributed to the medial and lateral tibiofemoral compartment respectively. The amount of associated injuries increased with ACLISS grading. The median scale value was 4.5 (lower quartile 3.0; higher quartile 7.0). Based on these quartiles, a score < 4 was considered to be an injury of mild severity (grade I), a score between ≥ 4 and ≤ 7 was defined as moderately severe (grade II) and a score > 7 displayed the most severe cases of ACL injuries (grade III). The knees were graded ACLISS I in 35%, ACLISS II in 49% and ACLISS III in 16% of patients. Overall, damage to the lateral tibiofemoral compartment was predominant (p < 0.01), but a proportional increase of tissue damage could be observed in the medial tibiofemoral compartment with the severity of ACLISS grading (p < 0.01). CONCLUSIONS: The ACLISS allowed to easily and rapidly identify different injury severity profiles in patients who underwent primary ACLR. Injury severity was associated with an increased involvement of the medial tibiofemoral compartment. The ACLISS is convenient to use in daily clinical practice and represents a feasible grading and documentation tool for a reproducible comparison of clinical data in ACL injured patients. LEVEL OF EVIDENCE: Level III.

Management after acute injury of the anterior cruciate ligament (ACL), part 2: management of the ACL-injured patient.

PURPOSE: The aim of this consensus project was to create a treatment algorithm for the management of the ACL-injured patient which can serve as an aid in a shared decision-making process. METHODS: For this consensus process, a steering and a rating group were formed. In an initial face-to-face meeting, the steering group, together with the expert group, formed various key topic complexes for which various questions were formulated. For each key topic, a structured literature search was performed by the steering group. The results of the literature review were sent to the rating group with the option to give anonymous comments until a final consensus voting was performed. Sufficient consensus was defined as 80% agreement. RESULTS: During this consensus process, 15 key questions were identified. The literature search for each key question resulted in 24 final statements. Of these 24 final statements, all achieved consensus. CONCLUSIONS: This consensus process has shown that ACL rupture is a complex injury, and the outcome depends to a large extent on the frequently concomitant injuries (meniscus and/or cartilage damage). These additional injuries as well as various patient-specific factors should play a role in the treatment decision. The present treatment algorithm represents a decision aid within the framework of a shared decision-making process for the ACL-injured patient. LEVEL OF EVIDENCE: Level V.

Reference standards for stress radiography measurements in knee ligament injury and instability: a systematic review.

PURPOSE: Stress radiographs are an easily accessible, cost-effective tool in the evaluation of acute and chronic ligament knee injuries. Stress radiographs provide an objective, quantifiable, and functional assessment of the injured ligament and can be a useful adjunct when planning surgical management and to objectively assess postoperative outcomes. This study aimed to review the literature reporting on stress radiographic techniques in evaluating knee ligament injury and instability and propose thresholds for interpreting stress radiography techniques. METHODS: The following three databases, OVID MEDLINE, the EMBASE library, and the Cochrane Controlled Trials Register, were systematically searched on January 23, 2023, for studies published from January 1970 to January 2023. The search extended to the reference lists of all relevant studies and orthopedic journals. Included studies were those that described a stress technique for the diagnosis of knee ligament injury; studies that reported a description or comparison of the accuracy and/or reliability of one or several stress radiography techniques, or studies that reported a comparison with alternative diagnostic modalities. RESULTS: Sixteen stress radiography techniques were reported for assessing the ACL with stress applied in the anterior plane, 10 techniques for assessing the PCL with stress applied in the posterior plane, 3 techniques for valgus stress, and 4 techniques for varus stress. The Telos device was the most commonly used stress device in the ACL and PCL studies. There was no consensus on the accuracy and reliability of stress radiography techniques for the diagnosis of any knee ligament injury. Stress radiography techniques were compared with alternative diagnostic techniques including instrumented arthrometry, MRI, and physical examination in 18 studies, with variability in the advantages and disadvantages of stress radiography techniques and alternatives. Analysis of results pooled from different studies demonstrated average delta gapping in knees with a completely injured ligament compared to the normal contralateral knee as per the following: for the ACL 4.9 ± 1.4 mm; PCL 8.1 ± 2.5 mm; MCL 2.3 ± 0.05 mm; and the FCL 3.4 ± 0.2 mm. CONCLUSION: Despite heterogeneity in the available literature with regard to stress examination techniques and device utilization, the data support that stress radiography techniques were accurate and reliable when compared to numerous alternatives in the diagnosis of acute and chronic knee ligament injuries. The present study also provides average increased ipsilateral compartment gapping/translation for specific knee ligament injuries based on the best available data. These values provide a reference standard for the interpretation of stress radiography techniques, help to guide surgical decision-making, and provide benchmark values for future investigations. LEVEL OF EVIDENCE: III.

Medial Varus Proximal Tibial Resection is Superior to Pie-Crusting of the Medial Collateral Ligament During Primary Total Knee Arthroplasty.

BACKGROUND: Medial varus proximal tibial (MPT) resection or soft tissue releases (STRs) of the medial collateral ligament (MCL) in the form of pie-crusting can be performed to achieve a balanced knee in a varus deformity. Studies comparing the 2 modalities have not been addressed within the literature. Therefore, the aims of this study were to assess the following: (1) compartmental changes between the 2 methods and (2) changes in patient-reported outcome measurements. METHODS: Using our institution's total joint arthroplasty registry, patients who underwent primary total knee arthroplasty from January 1, 2017, to December 31, 2019, were identified. The MPT resection and STR patients were 1:1 matched with baseline parameters yielding 196 patients. Outcomes of interest included: changes in compartmental pressures at 10, 45, and 90° degrees and change to the Short-Form 12, Western Ontario and McMaster Universities Osteoarthritis Index, and Forgotten Joint Scores (FJSs) at the 2-year follow-up period. A P value less than .05 was used as our threshold for statistical difference. RESULTS: The MPT resection led to significant reductions in compartmental pressures at 10° [43 versus 19 pounds (lbs.), P < .0001], 45° (43 versus 27 lbs., P < .0001), and 90° degrees (27 versus 16 lbs., P < .0001) compared to STR. MPT resection also had significantly improved Short-Form 12 (47 versus 38, P < .0001), Western Ontario and McMaster Universities Osteoarthritis Index (9 versus 21, P < .0001), and Forgotten Joint Score (79 versus 68, P = .005). CONCLUSION: Bone modification was superior to pie-crusting of the MCL in achieving consistent pressure balancing and improved outcomes. The investigation can guide surgeons on the preferred method to achieve a well-balanced knee.

Augmentation of the medial collateral ligament using suture tape reduces the recurrence after corrective surgery for severe hallux valgus.

BACKGROUND: The severity of hallux valgus (HV) deformity is associated with recurrence after corrective surgery because of the degenerative change of the medial capsule including the medial collateral ligament (MCL) at the metatarsophalangeal joint. This study aimed to assess the effectiveness of the MCL augmentation using a suture tape anchor of the recurrence of HV and to evaluate the histological changes of the medial joint capsule in HV patients. METHODS: Thirty-four feet with severe hallux valgus were included and divided into 2 groups. Seventeen feet had the MCL reconstruction using suture tape anchor with a combination of the corrective osteotomy as the suture tape group (mean age, 64.0 years), and other seventeen feet had the corrective osteotomy without MCL reconstruction as the control group (mean age, 62.0 years). HV angle (HVA) and intermetatarsal angle (IMA) on the weight-bearing radiograms and the Japanese Society for Surgery of the Foot (JSSF) score in both groups were compared at the final follow-up. The medial capsule was harvested from other 20 feet with HV and the relationship between the severity of HV and the histological findings was analyzed. RESULTS: HVA, IMA, and JSSF scores in both groups were significantly improved from preoperatively to the final follow-up (P < 0.01). At the final follow-up, HVA in the suture tape group (9.2°) was significantly smaller than that in the control (15.4°) (P < 0.01). There were no significant differences in the IMA and the JSSF score at the final follow-up between both groups. Histological scores in HV with ≥40° HVA was significantly worse than those in <40°. CONCLUSION: The medial joint capsule in severe HV deformity showed the degenerative change and the MCL reconstruction using suture tape combined with osteotomy provides a strong medial constraint to prevent the recurrence of the deformity in severe hallux valgus. LEVEL OF CLINICAL EVIDENCE: 3.

Mesenchymal Stem Cells for Enhanced Healing of the Medial Collateral Ligament of the Knee Joint.

Background and Objectives: The medial collateral ligament (MCL) is one of the major supporting ligaments of the knee joint, and MCL injuries are common where excessive valgus loading is applied to the knee joint. Although most MCL injuries can be treated conservatively, healing of the MCL can take several weeks to months. Furthermore, once injured, the biomechanical properties of the healed MCL differ from those of the native MCL, resulting in an increased risk of re-injury and chronic remnant symptoms. Mesenchymal stem cells (MSCs), owing to their therapeutic potential, have been investigated in various musculoskeletal injuries, and some preclinical studies regarding MSC-based approaches in MCL injuries have shown promising results. Despite satisfactory results in preclinical studies, there is still a lack of clinical studies in the orthopedic literature. This article describes the basic knowledge of the MCL, standard treatments for MCL injuries, and recent studies regarding the application of MSCs for enhanced healing of the MCL. MSC-based approaches are expected to be a potential therapeutic option for enhanced healing of the MCL in the future.

Medial collateral ligament injury of the knee: correlations between MRI features and clinical gradings.

OBJECTIVE: To evaluate the degree of correlation between MRI and clinical gradings of medial collateral ligament (MCL) injuries and assess for associated structures on MRI which may influence the clinical perception of MCL laxity. MATERIALS AND METHODS: All knee MRIs with acute MCL injuries between 2016 and 2020 at our centre were retrospectively reviewed by two blinded musculoskeletal radiologists. The clinic notes were reviewed for clinical gradings. RESULTS: One hundred and nineteen MRIs included. Forty-eight percent (57/119) agreement between MRI and clinical gradings (κ = 0.21, standard error (SE) 0.07). MRI grades: I 29% (34/119), II 50% (60/119), III 21% (25/119). Clinical grades: I 67% (80/119), II 26% (31/119), III 7% (8/119). In patients with clinical grade III MCL injury, there was waviness of the superficial MCL on MRI in 100% (8/8), deep meniscofemoral ligament tear in 75% (6/8), anterior cruciate ligament (ACL) partial or complete tear in 75% (6/8) and posteromedial corner (PMC) injury in 100% (8/8); compared with 0% (0/111), 34% (38/111), 44% (49/111) and 41% (46/111) respectively in clinical grade I or II injuries (p < 0.05). CONCLUSION: Agreement between MRI and clinical gradings of MCL injuries was only 'fair', with MRI almost always overestimating the grade of the injury when there was a mismatch. Waviness of the superficial MCL and injuries to the deep MCL, ACL and PMC correlate with clinical instability.

Morphological changes in the superficial medial collateral ligament on knee MR imaging: association with medial meniscal extrusion and posterior root medial meniscus abnormality.

OBJECTIVE: To assess the association between morphological changes in the superficial medial collateral ligament and meniscal extrusion with medial meniscus posterior root tear. MATERIALS AND METHODS: From January 1, 2018, to December 31, 2019, 124 patients who underwent knee MRI within 90 days prior to knee surgery and whose medial meniscus surgically proved intact, with posterior root tear or posterior horn tear, were enrolled. Two radiologists who were blinded to the surgical results assessed the morphological changes in the superficial medial collateral ligament, including thickness, bowing angle, and presence of signal intensity alteration, and medial meniscus extrusion, according to the presence of tears in the posterior root of the medial meniscus or posterior horn of the medial meniscus using the chi-square test, one-way ANOVA, and Cohen's kappa test. RESULTS: Thirty-six posterior root tears, 31 posterior horn tears, and 57 intact medial menisci were observed surgically. The mean values of thickness showed no significant differences among the three groups. The bowing angle was significantly higher in the posterior root tear than in the posterior horn tear (reader 1 = 0.001, reader 2 = 0.002) and normal meniscus groups (readers 1 and 2 < 0.001). The percentage of superficial medial collateral ligament signal intensity alteration and meniscal extrusion was highest in the group with posterior root of the medial meniscus tear (80.6% and 94.4%, respectively) and lowest in the group with normal medial meniscus (17.5% and 10.5%, respectively). CONCLUSION: Morphological changes in the superficial medial collateral ligament and meniscal extrusion were associated with medial meniscus posterior root tears.

Medial patellofemoral ligament MRI abnormalities in the setting of MCL injuries: are they clinically relevant?

OBJECTIVE: To assess MRI abnormalities of the medial patellofemoral ligament (MPFL) in patients with clinically and MRI-proven superficial medial collateral ligament (sMCL) injuries and determine the clinical significance. MATERIALS AND METHODS: High-field strength knee MRI examinations were selected which demonstrated sMCL injuries. These cases were retrospectively reviewed for the presence, location, and severity of MPFL abnormality. The MPFL was divided into a more superior transverse component arising from a femoral attachment (tMPFL), and a broader more inferior oblique decussation component (odMPFL) arising from the anterior margin of the upper sMCL. Chart review was performed to determine the clinical relevance of any MPFL findings. RESULTS: One hundred patients with MCL injury were identified. These included 37 grade I sprains, 33 partial tears, 20 high-grade partial tears, and 10 full thickness tears. Abnormal edema was present at the femoral attachment of the tMPFL in 83%. The odMPFL was abnormal in 90%, most commonly involving the femoral third. No patients had imaging evidence of concurrent lateral patellar dislocation on the initial MRI study. No patients had documented patellofemoral instability at the time of original injury or upon follow-up. No patients required MPFL reconstruction. CONCLUSION: The MRI appearance of the MPFL is abnormal in the majority of patients with clinically and MRI-documented sMCL sprains and tears. These cases had no evidence of concurrent lateral patellar dislocation on the initial MRI and did not develop patellar instability symptoms.

The association of bone bruising and grade of MCL injury in patients sustaining isolated MCL injuries.

OBJECTIVES: To investigate the incidence of bone bruising with isolated medial collateral ligament injury and to assess whether the presence of bone bruising is related to the injury grade. MATERIALS AND METHODS: Patients who sustained an acute isolated medial collateral ligament injury demonstrated on knee MRI between 2016 and 2020 were included in this study. Patient's characteristics and injury classification (clinical and radiological) were reviewed from clinical notes and imaging. The patients were divided into two groups, based on the presence of bone bruising. Fisher's exact test was used for dichotomous variables and odds ratios were computed in areas of clinical significance. RESULTS: Sixty patients with a median age of 37.6 ± 13.8 were included. Twenty-eight (46.7%) had bone bruising demonstrated on MRI scan. The bone bruising group were 7 times (95% CI [1.4;36.5]) more likely to have a complete disruption of the superficial medial collateral ligament and MRI grade III injury. Injury to the deep medial collateral ligament was more often observed in this group (p < 0.05). The most common location of bone bruising was the lateral femoral condyle (57.1%, 16/28) and/or the medial femoral condyle (57.1%, 16/28). CONCLUSIONS: The incidence of bone bruising with isolated medial collateral ligament injury is significant and is more common with radiologically higher grade injuries. There was no statistically significant difference between the anatomical location of bone bruise and the grade of MCL injury. Bone bruising patterns can help determine the mechanism of injury, with a valgus impact or avulsion type injury most commonly seen.

Transverse osteotomy closer to tibial plateau is associated with larger postoperative change in valgus laxity after open-wedge high tibial osteotomy.

PURPOSE: To identify the factors impacting changes in valgus laxity between before and after open-wedge high tibial osteotomy (OW-HTO) using quantitative valgus stress radiographs. METHODS: A total of 40 knees from 38 patients who underwent OW-HTO were assessed. The study population comprised 14 men and 24 women, with a mean age of 61.5 years. Valgus stress radiographs before and 1 year after OW-HTO were performed using a Telos device. The difference between pre- and postoperative joint line convergence angle (JLCA) was expressed as ΔJLCA (post-pre). As indicators of the proximal detachment of superficial medial collateral ligament (sMCL) on radiographs, two distances were defined: the distance from the level of the osteotomy starting point to the tangent line of the proximal tibial plateau (Distance A), or to the medial edge of the proximal tibial plateau (Distance B). Correlations between ΔJLCA and radiographic parameters or KOOS sub-scores were assessed using Spearman's rank correlation coefficient analysis. Receiver operator curves were generated to evaluate the predictive strength of the significant factor for an increase in ΔJLCA > 1°. RESULTS: Pre-operative OA severity consisted of Kellgren-Lawrence grade 2 (n = 18), 3 (n = 16), and 4 (n = 6). The average ΔJLCA (post-pre) was 0.5°, and ranged from - 1.4° to + 3.0°. The maximum systemic measurement error and limits of agreement were 0.07° and 0.20°, respectively. There were significant correlations between ΔJLCA and Distance A (36.9 ± 3.9 mm, R = - 0.46, p = 0.002), between ΔJLCA and Distance B (39.9 ± 4.0 mm, R = - 0.49, p = 0.001). The cut-off value for Distance A was determined to be 35 mm below the tibial plateau; the AUC was 0.804, with a sensitivity of 0.75 and a specificity of 0.82. Distance B correlated strongly with Distance A (R = 0.96, p < 0.001). There was no significant correlation between ΔJLCA and KOOS sub-scores 1 year after OW-HTO. CONCLUSIONS: Transverse osteotomy closer to tibial plateau was associated with larger valgus joint laxity postoperatively. This finding implies that sMCL proximal detachment, which was related to the level of the osteotomy starting point on the proximal tibia, potentially affected postoperative valgus laxity. LEVEL OF EVIDENCE: IV.

Kinematically aligned total knee arthroplasty restores more native medial collateral ligament strain than mechanically aligned total knee arthroplasty.

PURPOSE: Kinematically aligned total knee arthroplasty (KA TKA) targets restoration of patient-specific alignment and soft tissue laxity. However, whether KA TKA reproduces native soft tissue strain remains unclear. This cadaveric study tested the hypothesis that KA TKA would better restore the quantitative strain and strain distribution of medial collateral ligament (MCL) to the native healthy knee compared to mechanically aligned (MA) TKA. METHODS: Twenty-four fresh-frozen cadaver knees (12 pairs) were mounted on a customized knee squatting simulator to measure MCL strain during flexion. For each pair, one knee was assigned to KA TKA and the other to MA TKA. During KA TKA, the amount of femur and tibia resected was equivalent to implant thickness without MCL release using the calipered measuring technique. MA TKA was performed using conventional measured resection techniques. MCL strain was measured using a video extensometer (Mercury® RT RealTime tracking system, Sobriety s.r.o, Czech Republic). MCL strain and strain distribution during knee flexion were measured, and the measurements compared between native and post-TKA conditions. RESULTS: Mean and peak MCL strain were similar between KA TKA and native knees at all flexion angles (p > 0.1 at all flexion angles) while mean strain at all flexion angles and peak strain at ≥ 60º of MA TKA were approximately twice those of the native knees (p < 0.05 at ≥ 60º of flexion). In addition, greater MCL strain was observed in 4 of 12 regions of interest (ROI) after MA TKA (M1, M2, P1 and P2) compared to the native knee, whereas after KA TKA, MCL strain measurements were similar at all but 1 ROI (P2). CONCLUSIONS: KA TKA restored a more native amount and distribution of MCL strain compared to MA TKA. These findings provide clues for understanding why patients may experience better performance and more normal knee sensations after KA TKA compared to MA TKA. LEVEL OF EVIDENCE: Therapeutic study, Level I.

High incidence of superficial and deep medial collateral ligament injuries in 'isolated' anterior cruciate ligament ruptures: a long overlooked injury.

PURPOSE: In anterior cruciate ligament (ACL) injuries, concomitant damage to peripheral soft tissues is associated with increased rotatory instability of the knee. The purpose of this study was to investigate the incidence and patterns of medial collateral ligament complex injuries in patients with clinically 'isolated' ACL ruptures. METHODS: Patients who underwent ACL reconstruction for complete 'presumed isolated' ACL rupture between 2015 and 2019 were retrospectively included in this study. Patient's characteristics and intraoperative findings were retrieved from clinical and surgical documentation. Preoperative MRIs were evaluated and the grade and location of injuries to the superficial MCL (sMCL), dMCL and the posterior oblique ligament (POL) recorded. All patients were clinically assessed under anaesthesia with standard ligament laxity tests. RESULTS: Hundred patients with a mean age of 22.3 ± 4.9 years were included. The incidence of concomitant MCL complex injuries was 67%. sMCL injuries occurred in 62%, dMCL in 31% and POL in 11% with various injury patterns. A dMCL injury was significantly associated with MRI grade II sMCL injuries, medial meniscus 'ramp' lesions seen at surgery and bone oedema at the medial femoral condyle (MFC) adjacent to the dMCL attachment site (p < 0.01). Logistic regression analysis identified younger age (OR 1.2, p < 0.05), simultaneous sMCL injury (OR 6.75, p < 0.01) and the presence of bone oedema at the MFC adjacent to the dMCL attachment site (OR 5.54, p < 0.01) as predictive factors for a dMCL injury. CONCLUSION: The incidence of combined ACL and medial ligament complex injuries is high. Lesions of the dMCL were associated with ramp lesions, MFC bone oedema close to the dMCL attachment, and sMCL injury. Missed AMRI is a risk factor for ACL graft failure from overload and, hence, oedema in the MCL (especially dMCL) demands careful assessment for AMRI, even in the knee lacking excess valgus laxity. This study provides information about specific MCL injury patterns including the dMCL in ACL ruptures and will allow surgeons to initiate individualised treatment. LEVEL OF EVIDENCE: III.