Anterior cruciate ligament reconstruction with quadriceps tendon-patellar bone allograft: matched case control study.

BACKGROUND: Quadriceps tendon-patellar bone (QTPB) autograft is an excellent graft option with good clinical outcome. Use of QTPB autografts have increased because they minimize donor-site morbidity including anterior knee pain, while providing adequate mechanical strength. Although, there were many clinical results about allografts that used in anterior cruciate ligament (ACL) reconstruction, it have never been reported about the clinical outcome of ACL reconstruction with QTPB allograft. The purpose of this study is to evaluate the clinical outcome of ACL reconstruction with QTPB allograft and to compare with QTPB autograft. We hypothesized that ACL reconstruction with QTPB allograft had good functional outcomes and stability and no significant difference compared to the ACL reconstruction with QTPB autograft. METHODS: From February 2009 to January 2014, 213 cases who received ACL reconstruction with QTPB grafts were included. Forty-five patients who received ACL reconstruction with QTPB allograft were individually matched in age, sex, direction of the injured knee and body mass index (BMI) to a control group of 45 patients who received QTPB autograft. Clinical results were evaluated using International Knee Documentation Committee (IKDC) score, Lysholm score, Tegner scale, Knee injury and Osteoarthritis Outcome Score (KOOS) and ligament laxity. An average follow-up time was 31.2 months. RESULTS: The functional scores and ligament laxity improved from initial to the last visit in those with ACL reconstruction with QTPB allograft (p < 0.05). No significant statistical difference was found in clinical outcomes and complications including re-rupture between the QTPB allograft and autograft groups (p > 0.05). Laxity using anterior drawer test, Lachman test and KT-2000 showed no significant difference. No significant difference was found between the two groups in quadriceps peak extension torque, except at 60° per second at 6 months. CONCLUSION: QTPB allograft achieved good clinical outcome with no difference compared with QTPB autograft. QTPB allograft for ACL reconstruction is promising alternative to selected and compliant patients. Long-term follow-up needs to further evaluate the clinical outcomes and complications including re-rupture rate.

Large meniscus extrusion ratio is a poor prognostic factor of conservative treatment for medial meniscus posterior root tear.

PURPOSE: The purpose of this study was to find a prognostic factor of medial meniscus posterior root tear (MMPRT) for surgical decision making. METHODS: Eighty-eight patients who were diagnosed as acute or subacute MMPRT without severe degeneration of the meniscus were treated conservatively for 3 months. Fifty-seven patients with MMPRT showed good response to conservative treatment (group 1), while the remaining 31 patients who failed to conservative treatment (group 2) received arthroscopic meniscus repair. Their demographic characteristics and radiographic features including hip-knee-ankle angle, joint line convergence angle, Kellgren-Lawrence grade in plain radiographs, meniscus extrusion (ME) ratio (ME-medial femoral condyle ratio, ME-medial tibial plateau ratio, ME-meniscus width ratio), the location of bony edema, and cartilage lesions in MRI were compared. Receiver operating characteristic (ROC) curve analysis was also performed to determine the cut-off values of risk factors. RESULTS: The degree of ME-medial femoral condyle and medial tibia plateau ratio of group 2 was significantly higher than group 1 (0.08 and 0.07 vs. 0.1 and 0.09, respectively, both p < 0.001). No significant (n.s.) difference in other variables was found between the two groups. On ROC curve analysis, ME-medial femoral condyle ratio was confirmed as the most reliable prognostic factor of conservative treatment for MMPRT (area under ROC = 0.8). CONCLUSION: The large meniscus extrusion ratio was the most reliable poor prognostic factor of conservative treatment for MMPRT. Therefore, for MMPRT patients with large meniscus extrusion, early surgical repair could be considered as the primary treatment option. LEVEL OF EVIDENCE: III.

No difference in graft healing or clinical outcome between trans-portal and outside-in techniques after anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to compare femoral tunnel geometry including tunnel position, length, and graft bending angle between trans-portal and outside-in techniques in anterior cruciate ligament (ACL) reconstruction and discover whether such differences in tunnel geometry could influence graft healing or clinical outcome. METHODS: Sixty-four patients with anatomical single-bundle ACL reconstruction performed with either trans-portal technique (32 patients, one centre) or outside-in technique (32 patients, the other centre) were included in this retrospective study. Femoral tunnel location and length, and graft bending angle at the femoral tunnel were analysed on 3D CT knee model. The location and length of the femoral tunnel and graft bending angle were compared between the two techniques. All patients underwent MRI scans at around 1 year following ACL reconstruction. It was found that all patients had intact ACL graft on MRI images. On oblique axial image taken after ACL reconstruction to determine graft healing at femoral and tibial tunnels and the intra-articular portion, graft signal intensity ratio was calculated by dividing signal intensity (SI) of the reconstructed ACL by that of posterior cruciate ligament (PCL) in the region of interest selected with Marosis software. Clinical outcomes regarding Tegner activity scores, the International Knee Documentation Committee (IKDC) evaluation scores, Lachman test, and pivot shift test results were also compared between the two groups. RESULTS: While the location of femoral tunnel was similar to each other in both groups, the femoral tunnel length was longer in the outside-in technique (37.0 vs. 32.4 mm, p = .02). Meanwhile, the outside-in technique showed significantly more acute graft tunnel angle than the trans-portal technique (106.7° vs. 113.8°, p = .01). However, signal intensity ratios of grafts (compared with SI of PCL) were similar in femoral and tibial tunnels and intra-articular portions. Moreover, there were no statistically significant differences in terms of IKDC scores (89.4 vs. 90.5, n.s.) or Tegner activity scores (6.2 vs. 6.4, n.s.) between the two groups. There was no significant difference in measurement of Lachman or Pivot shift test either between the two groups. CONCLUSION: Even though the outside-in technique in ACL reconstruction created a more acute femoral graft bending angle and a longer femoral tunnel length than the trans-portal technique, these had no negative effect on graft healing. In addition, trans-portal and outside-in techniques in ACL reconstruction showed similar femoral tunnel positions and clinical outcomes. Acceptable graft healing and clinical outcomes can be obtained for both trans-portal and outside-in techniques in ACL reconstruction. LEVEL OF EVIDENCE: III.

Rotational alignment of femoral component with different methods in total knee arthroplasty: a randomized, controlled trial.

BACKGROUND: Femoral component rotation (FCR) is one of the most important factors in total knee arthroplasty. In this prospective study, we used three different techniques for FCR and analyzed their accuracy with postoperative axial computed tomography (CT) images. We also evaluated effect of FCR to clinical outcome. METHODS: One hundred sixty-five patients were randomly allocated into three groups. In the measured resection group, FCR was set by externally rotating the axis 3° off the posterior femoral condylar axis. In the tensor group, a gap-tensioning device set at 20 lbf was used. In the block group, spacer blocks of various thicknesses were used. The FCR angle (FCRa) was measured on postoperative axial CT as an angle between the clinical transepicondylar and posterior condylar axes of the femoral component. Outliers were defined as FCRas deviated more than 3° either internally or externally. Postoperative 2 year clinical scores and knee range of motion were checked. RESULTS: The tensor group had significantly better positioning of the femoral component to the neutral position compared with the measured resection group and the block group (mean FCRa: internal rotation 1.79, 0.43 and 2.63°, respectively, p < 0.001). The outliers were also least frequent in the tensor group (35, 16 and 40%, respectively, p = 0.02). There were no significant differences in postoperative 2 year clinical results among groups. CONCLUSIONS: Gap technique with a 20-lbf tensor device was the most accurate and precise method for obtaining adequate FCR. Measured resection with 3° external rotation and gap technique with blocks could lead to internal rotation of the femoral component. Postoperative 2 year clinical results were not significantly different among groups with different techniques for FCR. TRIAL REGISTRATION: The study was registered in the Clinical Research information Service (trial number: KCT0000129 ) in Korea. Registration date is 23rd of June, 2011.

Anterior tibial curved cortex is a reliable landmark for tibial rotational alignment in total knee arthroplasty.

BACKGROUND: Rotational alignment of the tibial component is important for long-term success of total knee arthroplasty (TKA). This study aimed to compare five axes in normal and osteoarthritic (OA) knees to determine a reliable landmark for tibial rotational alignment in TKA. METHODS: One hundred twenty patients with OA knees and 40 with normal knees were included. The angle between a line perpendicular to the surgical transepicondylar axis and each of five axes were measured on preoperative computed tomography. The five axes were as follows: a line from the center of the posterior cruciate ligament (PCL) to the medial border of the patellar tendon (PCL-PT), medial border of the tibial tuberosity (PCL-TT1), medial one-third of the tibial tuberosity (PCL-TT2), and apex of the tibial tuberosity (PCL-TT3), as well as the anteroposterior axis of the tibial prosthesis along the anterior tibial curved cortex (ATCC). RESULTS: For all five axes tested, the mean angles were smaller in OA knees than in normal knees. In normal knees, the angle of the ATCC axis had the smallest mean value and narrowest range (1.6° ± 2.8°; range, -1.7°-7.7°). In OA knees, the mean angle of the ATCC axis (0.8° ± 2.7°; range, -7.9°-9.2°) was larger than that of the PCL-TT1 axis (0.3° ± 5.5°; range, -19.7°-10.6°) (P = 0.461), while the angle of the ATCC axis had the smallest SD and narrowest range. CONCLUSION: The ATCC was found to be the most reliable and useful anatomical landmark for tibial rotational alignment in TKA.

Comparison of tunnel variability between trans-portal and outside-in techniques in ACL reconstruction.

PURPOSE: Although trans-portal and outside-in techniques are commonly used for anatomical ACL reconstruction, there is very little information on variability in tunnel placement between two techniques. METHODS: A total of 103 patients who received ACL reconstruction using trans-portal (50 patients) and outside-in techniques (53 patients) were included in the study. The ACL tunnel location, length and graft-femoral tunnel angle were analyzed using the 3D CT knee models, and we compared the location and length of the femoral and tibial tunnels, and graft bending angle between the two techniques. The variability in each technique regarding the tunnel location, length and graft tunnel angle using the range values was also compared. RESULTS: There were no differences in the average of femoral tunnel depth and height between the two groups. The ranges of femoral tunnel depth and height showed no difference between two groups (36 and 41 % in trans-portal technique vs. 32 and 41 % in outside-in technique). The average value and ranges of tibial tunnel location also showed similar results in two groups. The outside-in technique showed longer femoral tunnel than the trans-portal technique (34.0 vs. 36.8 mm, p = 0.001). The range of femoral tunnel was also wider in trans-portal technique than in outside-in technique. Although the outside-in technique showed significant acute graft bending angle than trans-portal technique in average values, the trans-portal technique showed wider ranges in graft bending angle than outside-in technique [ranges 73° (SD 13.6) vs. 53° (SD 10.7), respectively]. CONCLUSIONS: Although both trans-portal and outside-in techniques in ACL reconstruction can provide relatively consistent in femoral and tibial tunnel locations, trans-portal technique showed high variability in femoral tunnel length and graft bending angles than outside-in technique. Therefore, the outside-in technique in ACL reconstruction is considered as the effective method for surgeons to make more consistent femoral tunnel. LEVEL OF EVIDENCE: III.

Osteotomy configuration of the proximal wedge and analysis of the affecting factors in the medial open-wedge high tibial osteotomy.

PURPOSE: The purposes of this study were (1) to confirm the disparity of the measured thickness at the lateral hinge between anterior-posterior (AP) radiograph and 3D CT image, (2) to evaluate the affecting factors, and (3) to evaluate the differences between uniplanar and biplanar osteotomies. METHODS: From 2012 to 2014, a prospective comparative study was performed with 30 patients who received uniplanar osteotomy (group I) and 35 patients who received biplanar osteotomy (group II). For measurement of the proximal wedge, postoperative AP radiograph and 3D CT images were used. In the AP radiograph, medial and lateral bony bridge thicknesses were measured. In the 3D CT, the anterior and posterior images parallel to the coronal plane were selected for the evaluation. Coronal osteotomy slope was measured with the anterior image of the 3D CT scan. Sagittal osteotomy slope was measured with the sagittal section of the CT scan. RESULTS: Differences between the lateral bony bridge thicknesses measured in AP radiograph and the posterolateral posterolateral bony bridge thicknesses measured in 3D CT were statistically significant in both groups. Negative correlation was observed in the biplanar osteotomy group. Differences of the sagittal osteotomy slope from the native tibial slope showed negative correlation in the biplanar osteotomy group. CONCLUSION: Thickness of the posterolateral bony bridge was smaller compared to the observed thickness on the AP radiograph image that is routinely used for the follow-up. The thickness would be getting smaller if osteotomy is performed with an abrupt angle on the coronal plane and reverse slope on the sagittal plane. Therefore, osteotomy with abrupt angle on the coronal plane and reverse slope on the sagittal plane should be avoided for the proper thickness of the posterolateral bony bridge. LEVEL OF EVIDENCE: III.

What is the Ideal Degree of Extension After Primary Total Knee Arthroplasty?

BACKGROUND: Few studies have examined flexion contracture at the time of primary total knee arthroplasty (TKA) or how flexion contracture changes over time. The purpose of this study was to assess the ideal degree of extension immediately after TKA and to document postoperative changes in extension and clinical outcomes over 5-year follow-up. METHODS: This retrospective cohort study included 215 cases of primary TKA. Radiographic evaluations were performed on sagittal radiographs with the patient in the supine position and the knee in gravity and in passive extension using a stress device. Clinical outcomes were also measured. Four groups were defined on the basis of the extension angle during radiological evaluation: group 1, -10° to 0°; group 2, >0° to +5°; group 3, >+5° to +10°; group 4, >+10° in gravity. RESULTS: There were statistically significant differences in passive extension and gravity extension angles in groups 1, 3, and 4 with time-dependent and time*group (passive vs gravity) analyses, but not in group 2. The flexion contracture angles over 10° in gravity were decreased, although over 5° of flexion contracture remained at the final follow-up. Clinical outcomes were worse in groups 1 and 4 at the final follow-up. CONCLUSION: An extension angle between 0° and 5° in the passive extension position immediately after TKA can be considered ideal up to 5 years of follow-up. Patients with flexion contracture greater than 5° in passive extension and patients with hyperextension should be followed up to assess whether the condition will worsen.

Venous Thromboembolism Following Hip and Knee Replacement Arthroplasty in Korea: A Nationwide Study Based on Claims Registry.

The aim of this study was to examine the incidence and trends of clinically relevant venous thromboembolism (VTE) including deep vein thrombosis (DVT) and pulmonary embolism (PE) after hip and knee replacement arthroplasty (HKRA) in Korea. Between January 1 and December 31, 2010, 22,127 hip replacement arthroplasty (HRA) patients and 52,882 knee replacement arthroplasty (KRA) patients were enrolled in the analysis using the administrative claims database of the Health Insurance Review and Assessment Service (HIRA). All available parameters including procedure history and clinically relevant VTE during the 90 days after HKRA were identified based on diagnostic and electronic data interchange (EDI) codes. The overall incidence of VTE, DVT, and PE during the 90 days was 3.9% (n=853), 2.7% (n=597), and 1.5% (n=327) after HRA, while the incidence was 3.8% (n=1,990), 3.2% (n=1,699), and 0.7% (n=355) after KRA. The incidence of VTE after HKRA was significantly higher in patients who had previous VTE history (odds ratio [OR], 10.8 after HRA, OR, 8.5 after KRA), chronic heart failure (2.1, 1.3), arrhythmia (1.8, 1.7), and atrial fibrillation (3.4, 2.1) than in patients who did not. The VTE incidence in patients with chemoprophylaxis was higher than that in patients without chemoprophylaxis. The incidence of VTEs revealed in this retrospective review was not low compared with the results of the studies targeting other Asian or Caucasian populations. It may warrant routine prevention including employment of chemoprophylaxis. However, the limitation of the reviewed data mandates large scale prospective investigation to affirm this observation.

Different intraoperative kinematics with comparable clinical outcomes of ultracongruent and posterior stabilized mobile-bearing total knee arthroplasty.

PURPOSE: There remains no consensus as to whether mobile total knee arthroplasty (TKA) should use a posterior cruciate ligament-sacrificing ultracongruent (UC) or a posterior cruciate ligament-substituting posterior stabilized (PS) prosthesis. The purpose of this study was to assess intraoperative kinematics and clinical outcomes of UC and PS rotating platform mobile-bearing TKA. METHODS: In this randomized controlled study, mobile UC TKA prostheses (n = 45) were compared with mobile PS TKA prostheses (n = 45) with regard to intraoperative kinematics and clinical outcomes. The passive kinematic study using intraoperative navigation system included anterior/posterior translation, varus/valgus alignment and rotation of femur during flexion. The patients were clinically and radiographically evaluated over a 3-year follow-up. RESULTS: Paradoxical anterior translation of the femur was 10.8 ± 5.2 mm in the UC knee from 0° to 82° of knee flexion and 8.7 ± 3.0 mm in the PS knee from 0° to 70° of knee flexion (p = 0.027). Paradoxical internal rotation of the femur was 5.8° in the UC knees and 9.9° in the PS knees (p = 0.003). But, there was no significant difference between the groups in regard to the coronal alignment. There was no significant difference in the range of motion, KS knee scores, KS function scores, and WOMAC index scores. CONCLUSIONS: Despite different intraoperative kinematics between mobile UC and mobile PS TKA, neither design reproduced physiologic knee kinematics and there was no difference in clinical outcomes between the two groups. The clinical relevance of the study is that despite different intraoperative kinematics, UC design can be a considerable alternative to PS design in mobile-bearing TKA in respect of clinical outcomes. LEVEL OF EVIDENCE: II.

Extent of vertical cementing as a predictive factor for radiolucency in revision total knee arthroplasty.

PURPOSE: Limited information is available regarding the effects of cementing extent on implant stability in patients who have undergone revision total knee arthroplasty (TKA). As such, the goals of this study were: (1) to determine the correlation between the extent of vertical cementing and implant loosening; (2) to determine whether the extent of cementing is a potential predictive factor for radiolucency; and (3) to evaluate the minimal amount of cement needed for a stable implant during revision TKA using a hybrid technique. METHODS: One hundred nine stemmed/revision TKAs with a mean follow-up period of 5 years were retrospectively analysed. In each case, a single varus-valgus constrained implant was used and fixed with a hybrid technique. Implant stability was evaluated according to the modified Knee Society radiographic scoring system. The extent of vertical cementing was defined as the longitudinal length from the implant base to the end of the radiopaque line around the stem on radiograph. Its correlation with implant stability was analysed, and the minimal value for a stable implant was evaluated with a receiver operating characteristic (ROC) analysis. RESULTS: The mean extent of vertical cementing was longer in stable implants (femur: p = 0.001, tibia: p = 0.004) and significantly correlated with implant stability (femur: p < 0.001, tibia: p = 0.001). A logistic regression analysis revealed that the risk of loosening was 8.7-16.1 times higher when the extent of cementing was <40 mm, which was located at the stem-implant junction of the modular implant. The minimal extent of vertical cementing was estimated to be 60 mm for a stable femoral implant and 50 mm for a tibial implant. CONCLUSIONS: The hybrid fixation technique with a cementing extent >60 mm for the femur and 50 mm for the tibia was durable at a mean follow-up period of 5 years. Vertical cementing 10-20 mm above the stem-implant junction is recommended when performing revision TKA using this technique. LEVEL OF EVIDENCE: IV.

Anatomy of the anterior cruciate ligament insertion sites: comparison of plain radiography and three-dimensional computed tomographic imaging to anatomic dissection.

PURPOSE: The aim of this study was to provide quantitative data on insertion sites of anterior cruciate ligament (ACL) and to assess the correlation among measurements of anatomic dissection, plain radiographs, and 3D CT images to determine whether radiologic data can accurately reflect real anatomic measurements. METHODS: Fifteen cadaveric knees were assessed using the three measurement modalities. Lengths of the long and short axis, area, and centre position of each bundle insertion sites by quadrant method were examined on both the femur and tibia. Distances from the insertion centre to distal cortical and posterior cortical margins of condyle on femur, and distance between insertion centres on tibia were also inspected. RESULTS: The average ACL insertion position in the three measurement modalities was at 33.9 % in deep-shallow position and at 26.5 % in high-low position for anteromedial (AM) bundle and at 39.2 and 54.8 %, respectively, for posterolateral (PL) bundle in femur. For tibia, it was at 36.9 % in anterior-posterior position and 47.1 % in medial-lateral position for AM bundle and at 43.1 and 53.5 %, respectively, for PL bundle. The slight differences in various measurements among the three modalities were not statistically significant. CONCLUSIONS: The femoral insertion positions were considerably shallow and low, whereas tibial insertion positions were near the average compared to those in previous studies. Plain radiographic and 3D CT measurements showed a reliable correlation with anatomic dissection measurements. The clinical relevance is that plain radiographs rather than 3D CT can be used as a post-operative evaluation tool after ACL reconstruction.

Which analgesic mixture is appropriate for periarticular injection after total knee arthroplasty? Prospective, randomized, double-blind study.

PURPOSE: Although the analgesic effect of periarticular injection after total knee arthroplasty (TKA) has been well documented, the gold standard for drug combination has not yet been established. In this study, the analgesic effects of six different drug combinations were compared. METHODS: A total of 256 patients undergoing TKA for primary osteoarthritis were randomized into one of six groups: a control group (saline solution, epinephrine, and cefazolin, n = 42), Group 1 (ropivacaine, n = 43), Group 2 (ropivacaine + morphine, n = 43), Group 3 (ropivacaine + ketorolac, n = 42), Group 4 (ropivacaine + morphine + ketorolac, n = 43), and Group 5 (ropivacaine + morphine + ketorolac + methylprednisolone, n = 43). Pain level assessed by visual analogue scale (VAS) and opioid consumption were primary outcomes. The incidence of complications, range of motion (ROM), C-reactive protein (CRP) value, and the amount of post-operative blood drainage were also compared. RESULTS: Patients in Groups 4 and 5 complained less pain than the control group for the first 12 h after surgery, and the patients in the other groups showed less pain only during the initial 6 h after surgery. Groups 4 and 5 also showed less opioid consumption than the control group during the 24 h period after surgery. Patients in Group 5 showed no significant difference in VAS score and opioid consumption compared with Group 4, but they had lower CRP value and greater ROM than any other groups at post-operative day 2 and day 4. CONCLUSION: The combination of ropivacaine, morphine, and ketorolac showed a significantly stronger and sufficiently synergistic analgesic effect without adding methylprednisolone in periarticular injection after TKA. The clinical relevance of the study is that the combination of ropivacaine, morphine, and ketorolac can be a good option for periarticular injection following TKA in terms of synergistic analgesic effect and efficiency of drug combination.

Comparison of patellar resurfacing versus preservation in high flexion total knee arthroplasty.

PURPOSE: Recently, high flexion design total knee arthroplasty (TKA) has been introduced to improve clinical outcomes. The purpose of this study is to compare the midterm outcomes between patellar resurfacing (PR) and patellar preservation (PP) in high flexion TKA. METHODS: A total of 373 knees of primary TKAs were performed using high flexion design, 339 knees involved PR group and 34 knees involved PP group. After applying exclusion criteria, 1:3 matching was performed by the matching criteria. After matching, 69 knees in PR group and 23 knees in PP group remained. Radiographic outcomes, clinical outcomes, patients' satisfaction, ability and pain related to the high flexion activities were also evaluated. RESULTS: There was no significant difference in radiograph measurements, KS function score and WOMAC score (n.s). However, PR group showed better outcomes in KS knee score (P = 0.001) and HSS score (P = 0.03). There was no significant difference in postoperative satisfaction and ability of high flexion activities between the groups, but the pain at the high flexion activities in PP group was worse than that in PR group. CONCLUSION: In high flexion design of TKA, PR resulted in better midterm outcomes in regard to KS knee score, HSS score and knee pain related to the high flexion activities. The selective PR is recommended when performing primary TKA with high flexion design. LEVEL OF EVIDENCE: IV.

Biomechanical evaluation of anatomic single- and double-bundle anterior cruciate ligament reconstruction techniques using the quadriceps tendon.

PURPOSE: Quadriceps tendon grafts have renewed interest for ACL reconstruction; however, biomechanical studies comparing anatomic single-bundle (SB) and double-bundle (DB) reconstruction techniques are rare. The purpose of this study was to compare the knee biomechanics in four different types of anatomic ACL reconstruction techniques, using the quadriceps tendon in a human cadaver. METHODS: Four different tibial (T) and femoral (F) tunnel configurations, (a) DB-2F-2T, (b) DB-2F-1T, (c) SB-1F-1T and (d) DB-1F-2T, were used for ACL reconstruction using the split quadriceps tendon with patella bone. Ten cadaver knees were subjected to an 89 N anterior tibial load and combined 7 N m valgus and 5 N m internal torques. The anterior tibial translation (ATT) and in situ force were measured using a robotic system for the ACL-intact, ACL-deficient and ACL-reconstructed knees. RESULTS: DB reconstructions mostly restored ATT to the intact ACL. The in situ forces under the anterior load in the DB reconstructions were similar to the intact ACL, but that of the SB reconstruction was different at 30°, 60° and 90° of flexion (P < 0.05). Under combined torques, the in situ force of the SB graft was less than that of intact ACL at 0°, 15° and 30° of knee flexion (P < 0.05), while that of the ACL DB reconstruction was similar to the intact ACL. CONCLUSION: DB ACL reconstruction using quadriceps tendon can restore biomechanics of the knee to that of the intact ACL regardless of whether three or four tunnels are used, but SB reconstruction does not.

Painful patellar clunk or crepitation of contemporary knee prostheses.

BACKGROUND: Painful patellar clunk or crepitation (PCC) is a resurgent complication of contemporary posterior-stabilized TKA. The incidence, time to presentation, causes, and treatment of PCC still remain controversial. QUESTIONS/PURPOSES: We therefore (1) compared the incidence of PCC with five contemporary TKA designs, (2) evaluated the time to presentation, (3) identified possible etiologies, and (4) determined recurrence rate and change in knee functional scores after treatment for PCC. METHODS: We reviewed 580 patients who had 826 posterior-stabilized TKAs involving five different designs. The incidences of PCC were compared among the prostheses. The knees were divided into two groups depending on the development of PCC, and possible etiologic factors of PCC, including prosthesis design and surgical or radiographic variables, were compared between groups. We investigated the onset time of PCC and evaluated treatment results by knee outcome scores. Minimum followup was 2.0 years (mean, 3.9 years; range, 2.0-9.8 years). RESULTS: The PCC incidence was higher in the Press-Fit Condylar(®) Sigma(®) Rotating Platform/Rotating Platform-Flex Knee System (11 of 113 knees, 9.7%) than in the others (seven of 713 knees, 1.0%). Increased risk of PCC was associated with using a specific prosthesis and patellar retention. PCC occurred in all cases within a year after TKA (mean, 7.4 months). Arthroscopic treatment (16 knees) and patellar replacement (two knees) improved knee scores, with no recurrence observed over an average followup of 29 months. CONCLUSIONS: Prosthesis design and patellar retention were associated with PCC. Surgery resolved the PCC.

Is TKA using patient-specific instruments comparable to conventional TKA? A randomized controlled study of one system.

BACKGROUND: Patient-specific CT-based instrumentation may reduce implant malpositioning and improve alignment in TKA. However, it is not known whether this innovation is an advance that benefits patients. QUESTIONS/PURPOSES: We evaluated (1) the precision of patient-specific TKA by comparing the incidence of outliers in postoperative alignment between TKAs using patient-specific instruments and TKAs using conventional instruments, and (2) the reliability of patient-specific instruments by intraoperatively investigating whether the surgery could be completed with patient-specific instruments alone. METHODS: In this randomized controlled trial, we compared patient-specific TKA instruments from one manufacturer (n = 50) with conventional TKA instruments (n = 50). Postoperative hip-knee-ankle angles, femoral component rotation, and coronal and sagittal alignments of each component were measured. The validity of the patient-specific instrument was examined using cross-checking procedures with conventional instruments during the surgeries. When the procedure could not be completed accurately with patient-specific instruments, the procedure was converted to TKA using conventional instruments, and the frequency of this occurrence was tallied. RESULTS: Outliers in the hip-knee-ankle angle were comparable between groups (12% in the patient-specific instrument group and 10% in the conventional instrument group). Other parameters such as sagittal alignment and femoral component rotation did not differ in terms of outliers. Patient-specific guides were abandoned in eight knees (16%) during the surgery because of malrotation of the femoral components and decreased slope of the tibia. CONCLUSIONS: Accuracy was comparable between TKAs done with patient-specific instruments and those done with conventional instruments. However, the patient-specific instrument procedures had to be aborted frequently, incurring expenses that did not benefit patients.

Synovial membrane-derived mesenchymal stem cells supported by platelet-rich plasma can repair osteochondral defects in a rabbit model.

PURPOSE: The aim of this study was to determine the in vivo effectiveness of synovial membrane-derived mesenchymal stem cell (SDSC)-encapsulated injectable platelet-rich plasma (PRP) gel in the repair of damaged articular cartilage in the rabbit. METHODS: An osteochondral defect was created in the trochlear groove of the rabbit femur, and the defects were divided into 3 treatment groups: untreated control group, PRP group, and PRP-SDSC group. After 4, 12, and 24 weeks, the tissue specimens were assessed by macroscopic examination and histologic evaluation and stained immunohistochemically for type II collagen and proliferating cell nuclear antigen. In addition, total glycosaminoglycan content was determined at 24 weeks. RESULTS: Rabbit PRP contained a high concentration of platelets and high concentration of growth factors compared with those in whole blood. Twenty-four weeks after transplantation, there was fibrous tissue in the control group. In both the PRP group and the PRP-SDSC group, the defects were repaired with hyaline cartilage and exhibited significantly higher safranin O staining, type II collagen immunostaining, glycosaminoglycan content, cumulative histologic scores, and number of proliferating cell nuclear antigen-positive cells. However, incomplete bone regeneration and irregular cartilage surface integration were observed in the PRP group. CONCLUSIONS: Our results indicate that SDSC-embedded PRP gel could successfully resurface the defect with cartilage and restore the subchondral bone in the rabbit model. CLINICAL RELEVANCE: This study indicates that in an animal model, the application of PRP and SDSC in combination for the treatment of local cartilage defects appears promising; however, PRP-SDSC products might be more or less appropriate to treat different types of tissues and pathologies. The clinical efficacy of PRP remains under debate. Therefore further research is needed at both the basic science and clinical levels.

Revision total knee arthroplasty with varus-valgus constrained prosthesis versus posterior stabilized prosthesis.

PURPOSE: The aims of this retrospective study were to provide the basis for the choice of prosthesis in revision total knee arthroplasty (TKA) and to evaluate the outcome with varus-valgus constrained prosthesis compared with posterior stabilized (PS) prosthesis. METHODS: One hundred and five patients (121 knees) received revision TKA; of which thirty-seven patients (42 knees) received PS prosthesis and sixty-eight patients (79 knees) received varus-valgus constrained prosthesis. The mean follow-up duration was 64.8 ± 31.5 months and 63.2 ± 28.1 months in the PS and varus-valgus constrained groups, respectively. The criterion of prosthesis choice was a subjective laxity assessed by the surgeon intraoperatively. A multivariate analysis was performed to evaluate the preoperative factors in the choice of the prosthesis. RESULTS: The grade of femoral bone defect was the only factor that affected the choice of prosthesis. Clinical results improved significantly in both groups after surgery. There were no significant differences in clinical results between the two groups. Complication rates were 9.5 % in the PS group and 10.1 % in the varus-valgus constrained group, and the Kaplan-Meier survivorship analysis revealed 8-year component survival rates of 83.1 and 93.0 % in the PS and varus-valgus constrained groups, respectively. CONCLUSIONS: Femoral bone defect is an important factor to be considered in the choice of prosthesis for revision TKA. The varus-valgus constrained prosthesis showed an outcome similar to that of the PS prosthesis. For clinical relevance, varus-valgus constrained prosthesis is recommended in revision TKA when the PS prosthesis seems unsuitable for the management of instability. LEVEL OF EVIDENCE: III.

Preservation of the posterior cruciate ligament is not helpful in highly conforming mobile-bearing total knee arthroplasty: a randomized controlled study.

PURPOSE: The purpose of this study is to investigate whether the preservation of the posterior cruciate ligament (PCL) can be helpful for improving kinematics and clinical outcome in highly conforming mobile-bearing total knee arthroplasty (TKA). METHODS: Ninety osteoarthritic knees were randomly allocated to either the PCL-preserving group or the PCL-sacrificing group. Passive kinematics was recorded with a navigation system immediately after implantation. Three parameters (anterior/posterior translation, varus/valgus rotation, and internal/external rotation) were analysed from 0° to 120° flexion. RESULTS: The PCL-preserving group (42 knees) had more varus rotation over 90° flexion (p < 0.05) and more anterior translation of the femur in all ranges of flexion (p < 0.05) than those in the PCL-sacrificing group (44 knees). There was no difference in the internal/external rotation (p > 0.05). The range of motion, functional scores, and radiographic results did not significantly differ between the two groups at the final follow-up. Three knees in the PCL-preserving group were revised: two presented with instability caused by traumatic attenuation of the PCL and one with subluxation of the insert due to a tight PCL. CONCLUSION: The preservation of the PCL was not helpful for improving kinematics and clinical outcome in highly conforming mobile-bearing TKA.