Allogeneic Umbilical Cord Blood-Derived Mesenchymal Stem Cell Implantation Versus Microfracture for Large, Full-Thickness Cartilage Defects in Older Patients: A Multicenter Randomized Clinical Trial and Extended 5-Year Clinical Follow-up.

BACKGROUND: There is currently no optimal method for cartilage restoration in large, full-thickness cartilage defects in older patients. PURPOSE: To determine whether implantation of a composite of allogeneic umbilical cord blood-derived mesenchymal stem cells and 4% hyaluronate (UCB-MSC-HA) will result in reliable cartilage restoration in patients with large, full-thickness cartilage defects and whether any clinical improvements can be maintained up to 5 years postoperatively. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A randomized controlled phase 3 clinical trial was conducted for 48 weeks, and the participants then underwent extended 5-year observational follow-up. Enrolled were patients with large, full-thickness cartilage defects (International Cartilage Repair Society [ICRS] grade 4) in a single compartment of the knee joint, as confirmed by arthroscopy. The defect was treated either with UCB-MSC-HA implantation through mini-arthrotomy or with microfracture. The primary outcome was proportion of participants who improved by ≥1 grade on the ICRS Macroscopic Cartilage Repair Assessment (blinded evaluation) at 48-week arthroscopy. Secondary outcomes included histologic assessment; changes in pain visual analog scale (VAS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and International Knee Documentation Committee (IKDC) score from baseline; and adverse events. RESULTS: Among 114 randomized participants (mean age, 55.9 years; 67% female; body mass index, 26.2 kg/m2), 89 completed the phase 3 clinical trial and 73 were enrolled in the 5-year follow-up study. The mean defect size was 4.9 cm2 in the UCB-MSC-HA group and 4.0 cm2 in the microfracture group (P = .051). At 48 weeks, improvement by ≥1 ICRS grade was seen in 97.7% of the UCB-MSC-HA group versus 71.7% of the microfracture group (P = .001); the overall histologic assessment score was also superior in the UCB-MSC-HA group (P = .036). Improvement in VAS pain, WOMAC, and IKDC scores were not significantly different between the groups at 48 weeks, however the clinical results were significantly better in the UCB-MSC-HA group at 3- to 5-year follow-up (P < .05). There were no differences between the groups in adverse events. CONCLUSION: In older patients with symptomatic, large, full-thickness cartilage defects with or without osteoarthritis, UCB-MSC-HA implantation resulted in improved cartilage grade at second-look arthroscopy and provided more improvement in pain and function up to 5 years compared with microfracture. REGISTRATION: NCT01041001, NCT01626677 (ClinicalTrials.gov identifier).

One-Stage Anatomical Revision Anterior Cruciate Ligament Reconstruction: Results According to Tunnel Overlaps.

PURPOSE: To present clinical results according to tunnel overlap in 1-stage anatomical revision anterior cruciate ligament reconstruction (ACLR). METHODS: All patients who underwent revision ACLR performed by a single surgeon (J.H.A.) from 2012 to 2017 and were followed up for >24 months were retrospectively evaluated. The exclusion criteria were concomitant ligament injury, including medial collateral ligament injury, modified Outerbridge grade ≥3 cartilage lesion, and severe meniscus defects. Tunnel overlap was measured on 3-dimensionally reconstructed computed tomography images. Patients in the nonoverlapped femoral tunnel group (group NO, n = 52) were treated with new tunnel drilling that completely avoided previous tunnels, and those in the overlapped femoral tunnel group (group O, n = 41) were treated with a new tunnel that overlapped with previous tunnels. Clinical outcomes were evaluated using the subjective International Knee Documentation Committee (IKDC) and Lysholm scores. Knee joint stability was measured using the Lachman and pivot shift tests. Patients with femoral tunnel widening of ≥14 mm underwent 2-stage ACLR. RESULTS: The mean follow-up duration of 93 patients was 46.9 months (range, 24-97 months). All preoperative subjective and objective IKDC (P<0.001) and Telos stress test scores (P = .016) were significantly improved at the last follow-up. Forty-one patients had overlapping femoral tunnels, whereas 87 had overlapping tibial tunnels. At the last follow-up, subjective IKDC and Lysholm scores (73.6 ± 15.3 vs 74.9 ± 12.1, P = .799 and 80.0 ± 19.2 vs 81.44 ± 13.5, P = .505, respectively) and objective pivot shift (IKDC grade) in the Lachman test (P = .183 and P = .450, respectively) did not differ significantly between groups NO and O, respectively. CONCLUSIONS: One-stage anatomical revision ACLR significantly improved the clinical results. Most tibial tunnels (94%) and approximately one-half (44%) of the femoral tunnels overlapped. The overlapped femoral tunnel group did not show inferior outcomes or stability. LEVEL OF EVIDENCE: Level III, cohort study.

Postoperative radiologic outcome comparison between conventional and computer-assisted navigation total knee arthroplasty in extra-articular tibia vara.

PURPOSE: Total knee arthroplasty (TKA) is the definite treatment for osteoarthritis. Meanwhile, significant inherent extra-articular varus angulation is associated with abnormal postoperative hip-knee-ankle (HKA) angle. Computer-assisted navigation TKA (CAS-TKA) used in patients who have severe varus deformity. The purpose of this study was to compare postoperative radiologic outcome between CAS-TKA and conventional TKA for extra-articular tibia vara. METHODS: A retrospective review of postoperative HKA on standing lower extremity views was conducted in patients who underwent TKA by a single surgeon from 2010 to 2018, including knee with conventional TKA (n = 83) and CAS-TKA (n = 246). Extra-articular tibia vara was assessed by measuring the metaphyseal-diaphyseal angle (MDA) of the tibia in preoperative standing lower extremity view. Postoperative alignment was assessed by measuring the HKA in postoperative standing lower extremity view. RESULTS: There was no significant difference in age (p = 0.063), gender (p = 0.628), body mass index (p = 0.426), preoperative range of motion (p = 0.524), preoperative HKA (p = 0.306), preoperative MDA (p = 0.523), or postoperative HKA (p = 0.416) between the two groups (conventional TKA and CAS-TKA). There was no significant difference in postoperative alignment for cases with MDA ≤4° (p = 0.351) or MDA >4° (p = 0.866) in each group. There was a positive correlation between preoperative HKA and postoperative HKA in the CAS-TKA group (p < 0.001, r = 0.243). However, there was no significant correlation between preoperative HKA and postoperative HKA in the conventional TKA group (p = 0.732). CONCLUSIONS: There was no significant difference in postoperative alignment between conventional TKA and CAS-TKA in extra-articular tibial vara even for cases with MDA >4°.

Sclerosing osteomyelitis of Garré: A confusing clinical diagnosis.

We describe a rare case of sclerosing osteomyelitis of Garré in a 63-year-old woman with uncontrolled right thigh pain. She had suffered from lower back pain and radiating pain on the right lower leg for a year and 4 months and so had spine surgery 8 months ago. But the right thigh pain persisted, and the levels of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) remained abnormal. Right femur radiographs showed cortical thickening on the proximal femur. Magnetic resonance images showed T2 hypersignal intensity lesions in the proximal femur. Under suspicion of osteoid osteoma or sclerosing osteomyelitis, surgery was performed with biopsy, bone curettage, and drilling. The culture was negative, and the biopsy showed chronic osteomyelitis. Despite surgery, the levels of CRP and ESR still remained abnormal. After using venous antibiotics, the pain subsided and CRP and ESR levels turned to normal. Followed by 6 weeks of oral antibiotics, pain was relieved after 1-year follow-up.

Magnetic Resonance Imaging and Clinical Results of Outside-in Anterior Cruciate Ligament Reconstruction: A Comparison of Fixed- and Adjustable-Length Loop Cortical Fixation.

BACKGROUND: Cortical suspensory femoral fixation is commonly performed for graft fixation to the femur in anterior cruciate ligament (ACL) reconstruction using hamstring tendons. The purpose of this study was to compare graft healing in the femoral tunnel, implant-related failure, and clinical results between fixed- and adjustable-length loop devices in outside-in ACL reconstruction. METHODS: A total of 109 patients who underwent ACL reconstruction using the outside-in technique from December 2010 to July 2014 were included. For femoral graft fixation, a fixed-length loop device was used in 48 patients (fixed-loop group) and an adjustable-length loop device was used in 61 patients (adjustable-loop group). For evaluation of graft healing in the femoral tunnel, magnetic resonance imaging was performed at postoperative 6 months and the signal-to-noise ratios (SNRs) of the tendon graft and tendon-bone interface in the femoral bone tunnel were evaluated. The presence of synovial fluid was evaluated to determine loop lengthening at the femoral tunnel exit. Clinical results assessed using International Knee Documentation Committee score, Tegner-Lysholm Knee Scoring scale, and knee instability tests were compared between groups. RESULTS: The SNRs of the tendon graft and tendon-bone interface were not statistically different between groups. The presence of synovial fluid at the femoral exit showed no statistical difference between groups. Clinical results were not significantly different between groups. CONCLUSIONS: The adjustable-length loop device provided comparable graft healing, implant-related failure, and clinical results with the fixed-length loop device, allowing adaptation of the graft to the different tunnel lengths. Therefore, it could be effectively used with an adjustment according to the femoral tunnel length.

Three-dimensional scapular dyskinesis in hook-plated acromioclavicular dislocation including hook motion.

BACKGROUND: The purpose of this study is to analyze the 3-dimensional scapular dyskinesis and the kinematics of a hook plate relative to the acromion after hook-plated acromioclavicular dislocation in vivo. Reported complications of acromioclavicular reduction using a hook plate include subacromial erosion and impingement. However, there are few reports of the 3-dimensional kinematics of the hook and scapula after the aforementioned surgical procedure. METHODS: We studied 15 cases of acromioclavicular dislocation treated with a hook plate and 15 contralateral normal shoulders using computed tomography in the neutral and full forward flexion positions. Three-dimensional motion of the scapula relative to the thorax during arm elevation was analyzed using a computer simulation program. We also measured the distance from the tip of the hook plate to the greater tuberosity, as well as the angular motion of the plate tip in the subacromial space. RESULTS: Decreased posterior tilting (22° ± 10° vs 31° ± 8°) in the sagittal plane and increased external rotation (19° ± 9° vs 7° ± 5°) in the axial plane were evident in the affected shoulders. The mean values of translation of the hook plate and angular motion against the acromion were 4.0 ± 1.6 mm and 15° ± 8°, respectively. The minimum value of the distance from the hook plate to the humeral head tuberosity was 6.9 mm during arm elevation. CONCLUSIONS: Acromioclavicular reduction using a hook plate may cause scapular dyskinesis. Translational and angular motion of the hook plate against the acromion could lead to subacromial erosion. However, the hook does not seem to impinge directly on the humeral head.

Should We Check the Routine Postoperative MRI for Hematoma in Spinal Decompression Surgery?

BACKGROUND: A postoperative magnetic resonance imaging (MRI) is performed as a routine to assess decompression of the spinal cord as well as to evaluate postoperative complications. The purpose of this study is to analyze the efficacy of postoperative MRI for hematoma in spinal decompression surgery. METHODS: Between January 1, 2008 and January 31, 2015, 185 patients who underwent postoperative MRI after spinal decompression surgery were included in this study. We checked the history of the use of an anticoagulant or antiplatelet agent, withdrawal period, blood platelet count, and prothrombin time (international normalized ratio [INR]). We measured the total amount of suction drainage and duration until removal. We retrospectively reviewed the presence of hematoma and thecal sac compression. Postoperative prognosis was evaluated by a visual analog scale (VAS) and the Oswestry Disability Index (ODI). RESULTS: Hematomas were found on postoperative MRI scans in 97 out of 185 patients (52.4%). Thirty patients had a thecal sac compressing hematoma: 7 in the cervical spine, 1 in the thoracic spine, and 22 in the lumbar spine. The occurrence of hematoma did not show significant difference according to the use of an anticoagulant (p = 0.157). The blood platelet count, prothrombin time (INR), and suction drainage duration did not have a statistically significant correlation with the occurrence of hematoma (p = 0.562, p = 0.506, and p = 0.429, respectively). The total amount of suction drainage was significantly different according to the presence of hematoma (p = 0.022). The total 185 patients had a significant decrease in the postoperative VAS score (p < 0.001), and the diminution of VAS score was not significantly different according to the occurrence of hematoma (p = 0.243). Even in the cases of thecal sac compressing hematoma, the reduction of VAS score was not significantly different (p = 0.689). CONCLUSIONS: Postoperative MRI for hematoma in spinal decompression surgery has little effect on prognosis or management. Therefore, indiscriminate postoperative MRI should be avoided and MRI should be performed depending on the patient's status.

Comparison of transtibial and retrograde outside-in techniques of anterior cruciate ligament reconstruction in terms of graft nature and clinical outcomes: a case control study using 3T MRI.

INTRODUCTION: This study was performed to compare ACL graft maturation and morphologies using MRI between trans-tibial (TT) and retrograde outside-in (OI) techniques, and to compare clinical outcomes between the two groups. MATERIALS AND METHODS: Patients underwent single-tunnel ACL reconstruction using quadrupled hamstring autografts, with the TT technique used on 42 patients (TT group) and the retrograde OI technique used on 39 patients (OI group). All patients were examined with 3 T MRI at 6 months (between 5 and 7 months) after surgery. The signal intensity of the reconstructed graft was analyzed and compared between the two groups, using the signal/noise quotient (SNQ), the orientation of the ACL graft and the tibial tunnel location of the graft. The SNQ value is indicative of graft maturation, and the orientation of the graft and the tibial tunnel location of the graft represent graft morphology. Clinical evaluation was performed before the surgery and 2 years or more after the surgery. RESULTS: The mean SNQ value of the TT group was significantly (P = 0.030) lower than that of the OI group. The mean sagittal ACL angle (P < 0.001) and the mean coronal ACL angle (P < 0.001) were more vertical in the TT group. The tibial tunnel aperture was located at a significantly (P < 0.001) more posterior position in the TT group. There was no statistically significant difference in the clinical results between the two groups. CONCLUSIONS: The OI technique showed a more anteriorly positioned tibial tunnel and a more oblique graft orientation in both sagittal and coronal planes. However, in comparison with the TT group, a significantly higher SNQ value was noticed in the follow-up MRI of the OI group at 6 months, although clinical results of the two groups were not significantly different during at least the 2-year follow-up.

Graft bending angle is correlated with femoral intraosseous graft signal intensity in anterior cruciate ligament reconstruction using the outside-in technique.

BACKGROUND: The purposes of this study were as follows: 1) to determine the correlation between the bending angle of the anterior cruciate ligament (ACL) graft at the femoral tunnel and the magnetic resonance imaging (MRI) signal intensity of the ACL graft and 2) to analyze the difference in the MRI signal intensity of the reconstructed ACL graft in different areas of the graft after single-bundle hamstring autograft ACL (SB ACL) reconstruction using an outside-in (OI) technique with bone-sparing retro-reaming. METHODS: Thirty-eight patients who underwent SB ACL reconstruction with the hamstring tendon autograft using the OI technique were enrolled in this study. All patients were assessed using three-dimensional computed tomography (CT) to evaluate femoral tunnel factors, including tunnel placement, tunnel length, tunnel diameter, and femoral tunnel bending angle. At a mean of 6.3±0.8months after surgery, 3.0-T MRI was used to evaluate the graft signal intensity using signal/noise quotient for high-signal-intensity lesions. RESULTS: Among various femoral tunnel factors, only the femoral tunnel bending angle in the coronal plane was significantly (p=0.003) correlated with the signal/noise quotient of the femoral intraosseous graft. The femoral intraosseous graft had significantly (p=0.009) higher signal intensity than the other graft zone. Five cases (13.2%) showed high-signal-intensity zones around the femoral tunnel but not around the tibial tunnel. CONCLUSION: After ACL reconstruction using the OI technique, the graft bending angle was found to be significantly correlated with the femoral intraosseous graft signal intensity, indicating that increased signal intensity by acute graft bending might be related to the maturation of the graft. LEVEL OF EVIDENCE: This was a retrospective comparative study with Level III evidence.

Comparison between conservative treatment and arthroscopic pull-out repair of the medial meniscus root tear and analysis of prognostic factors for the determination of repair indication.

INTRODUCTION: This study was undertaken to compare the clinical outcomes between the conservative treatment and pull-out repair of the medial meniscus root tear (MMRT), and to analyze the prognostic factors of the MMRT repair for the determination of repair indication. MATERIALS AND METHODS: 38 patients, diagnosed with a MMRT between August 2010 and February 2012, were retrospectively evaluated. Among these patients, 25 patients (pull-out repair group) underwent arthroscopic pull-out repair and the remaining 13 patients (conservative treatment group) underwent conservative management. Two groups were compared using the final clinical outcomes (using Tegner and Lysholm activity scale, IKDC subjective score). For the analysis of prognostic factors of the pull-out repair, patients' factors, radiologic, and magnetic resonance imaging factors were evaluated. Degrees of varus alignment (≥5°) and cartilage status (≥outerbridge III) were employed as a cut-off value in comparing the final clinical outcomes among the subgroups. RESULTS: In the final clinical results, the MMRT pull-out repair group had better IKDC subjective scores (p < 0.001), Tegner and Lysholm activity scale (p = 0.017). In the MMRT pull-out repair group, mild varus knee patient achieved better clinical outcome than the severe varus knee patient (p = 0.006). And the mild cartilage degenerative patient group achieved better outcomes than the severe cartilage degenerative patient group (p = 0.009). However, there was no significant difference between the severe varus alignment group and conservative treatment group (p = 0.487). Severe cartilage changes also show no significant difference (p = 0.643). CONCLUSIONS: The MMRT pull-out repair group had better clinical results than that the conservative treatment group. However, severe varus alignment and severe degeneration of cartilage status were a poor prognostic factor, and there was no significant difference between the severe varus alignment or severe cartilage change and the conservative treatment group in the clinical results. The other optional treatment could be recommended for patients who have MMRT with a severe varus knee alignment or severe cartilage.

Three-dimensional reconstruction computed tomography evaluation of tunnel location during single-bundle anterior cruciate ligament reconstruction: a comparison of transtibial and 2-incision tibial tunnel-independent techniques.

BACKGROUND: Anatomic tunnel positioning is important in anterior cruciate ligament (ACL) reconstructive surgery. Recent studies have suggested the limitations of a traditional transtibial technique to place the ACL graft within the anatomic tunnel position of the ACL on the femur. The purpose of this study is to determine if the 2-incision tibial tunnel-independent technique can place femoral tunnel to native ACL center when compared with the transtibial technique, as the placement with the tibial tunnel-independent technique is unconstrained by tibial tunnel. METHODS: In sixty-nine patients, single-bundle ACL reconstruction with preservation of remnant bundle using hamstring tendon autograft was performed. Femoral tunnel locations were measured with quadrant methods on the medial to lateral view of the lateral femoral condyle. Tibial tunnel locations were measured in the anatomical coordinates axis on the top view of the proximal tibia. These measurements were compared with reference data on anatomical tunnel position. RESULTS: With the quadrant method, the femoral tunnel centers of the transtibial technique and tibial tunnel-independent technique were located. The mean (± standard deviation) was 36.49% ± 7.65% and 24.71% ± 4.90%, respectively, from the over-the-top, along the notch roof (parallel to the Blumensaat line); and at 7.71% ± 7.25% and 27.08% ± 7.05%, from the notch roof (perpendicular to the Blumensaat line). The tibial tunnel centers of the transtibial technique and tibial tunnel-independent technique were located at 39.83% ± 8.20% and 36.32% ± 8.10%, respectively, of the anterior to posterior tibial plateau depth; and at 49.13% ± 4.02% and 47.75% ± 4.04%, of the medial to lateral tibial plateau width. There was no statistical difference between the two techniques in tibial tunnel position. The tibial tunnel-independent technique used in this study placed femoral tunnel closer to the anatomical ACL anteromedial bundle center. In contrast, the transtibial technique placed the femoral tunnel more shallow and higher from the anatomical position, resulting in more vertical grafts. CONCLUSIONS: After single-bundle ACL reconstruction, three-dimensional computed tomography showed that the tibial tunnel-independent technique allows for the placement of the graft closer to the anatomical femoral tunnel position when compared with the traditional transtibial technique.

Meniscectomy.

To review the meniscus from a historical perspective especially on surgical management and general guidelines for arthroscopic meniscectomy procedures for various types of meniscal tears. We searched MEDLINE and PubMed for the years of 1980-2010 using the terms meniscus, meniscal repair, menisectomy, and arthroscopy. Orthopedic surgeons frequently encounter patients with pain or functional impairment of the knee joint and repair or resection of the injured meniscus is one of the most common orthopedic operative procedures. The object of meniscal surgery is to reduce pain, restore functional meniscus and prevent the development of degenerative osteoarthritis in the involved knee. Historically, total meniscectomy was a common procedure performed for meniscus tear symptoms. However, it has been reported that total meniscectomy has deleterious effects on the knee. In the past, the menisci were thought as a functionless remnant tissue. Currently, it is known that the meniscus is an important structure for knee joint function. Menisci provide several vital functions including mechanical support, localized pressure distribution, and lubrication to the knee joint. It is widely accepted that the function of the meniscus can be preserved through minimal excision. An arthroscopic partial meniscectomy preserving more of the meniscus is preferred over total meniscectomy. In recent decades, this shift toward arthroscopic partial meniscectomy has led to the development of new surgical techniques.

Prediction of the rotational state of the humerus by comparing the contour of the contralateral bicipital groove: Method for intraoperative evaluation.

BACKGROUND: Accurate reduction of rotational displacement for transverse or comminute fracture of humeral shaft fracture is difficult during operation. The purpose of this study was to evaluate the reliability of the bicipital groove as a point of reference for the prediction of the rotational state of the humerus on two dimensional images of C-arm image intensifier during operation for humeral shaft fractures. MATERIALS AND METHODS: One hundred subjects, 62 male, 38 female, aged 22-53 years were recruited contralateral bicipital groove on the 45 degrees externally rotational standard anterior-posterior view recorded before surgery. Three observers, watched only contour of bicipital groove in monitor of C-arm image intensification with naked eye without looking at the subject and predicted rotational state of the humerus by comparing the contour of the opposite side of bicipital groove. The angle of discrepancy from real rotational position was then assessed. RESULTS: The mean (SD), angular discrepancy between the neutral point and the predicted angle was 3.4°(±2.7°). A value within 5° was present in 72% of cases. All observations were within 15°. There was no interobserver variation (P = 0.47). The intraclass correlation coefficient (ICC) was 0.847. CONCLUSION: Contour of the bicipital groove on simple radiograph was a useful landmark. Comparing the contour of the bicipital groove in the 45 degrees externally rotational standard view bilaterally, was an effective method for reduction of rotational displacement of the humerus.

The effect of intra-articular autogenous bone marrow injection on healing of an acute posterior cruciate ligament injury in rabbits.

PURPOSE: The purpose was to identify the effect of intra-articular autogenous bone marrow injection on the healing of an acute posterior cruciate ligament (PCL) rupture in a rabbit model. The effect of autogenous bone marrow on the healing process was assessed serially by gross inspection, histologic examination, and immunohistochemical study of growth factors. METHODS: In both knee joints, the PCL was completely transected surgically near the femoral attachment site in 24 rabbits. Autogenous bone marrow was obtained from both tibias and delivered only to the right knee joint by direct intra-articular injection. Gross inspection, histologic examination, and immunohistochemical study of growth factors were performed at 8, 12, and 16 weeks after severing of the posterior cruciate ligament (PCL) among 8 randomly chosen specimens. The degree of healing in both marrow-stimulated and untreated control ligaments was evaluated by gross inspection using an ordinal scale consisting of 5 grades. The degree of fibroblast and vessel proliferation and alignment of collagen fibers were evaluated by histologic examination. The degree of expression of transforming growth factor ß1, epidermal growth factor receptor, and vascular endothelial growth factor was evaluated by immunohistochemical study. Statistical analysis was performed with the Mann-Whitney U test. RESULTS: In the group with marrow-stimulated ligaments, the degree of healing was higher at 8 and 12 weeks by gross examination, whereas there was no significant difference at 16 weeks between the 2 groups. According to histologic examination, the healing process was faster in the bone marrow injection group than in the control group at 8 and 12 weeks because the degree of fibroblast and vessel proliferation significantly declined and collagen fibers were arranged more regularly compared with the control group. Similar to the results of histologic examination, the results of immunohistochemical studies showed that the healing process was faster in the bone marrow injection group. However, the recovery of the PCL was completed at 16 weeks after PCL resection in both the bone marrow injection group and the control group. CONCLUSIONS: Intra-articular autogenous bone marrow injection appeared to promote the initiation of healing response in acutely injured PCLs in rabbits. CLINICAL RELEVANCE: Intra-articular autogenous bone marrow injection can be a viable option for treating acutely injured PCLs.