Open wedge high tibial osteotomy does not decrease patellar height relative to femur: A three-dimensional computer model analysis.

BACKGROUND: Patellar height, which decreases after open wedge high tibial osteotomy (OWHTO), has conventionally been assessed by tibial references using lateral radiographs of the knee; however, changes in the proximal tibia shape after OWHTO may affect this method. We aimed to evaluate the changes in patellar height position relative to the transepicondylar axis of the femur after OWHTO using in vivo three-dimensional (3D) computer models. METHODS: Fourteen patients who underwent 3D magnetic resonance imaging (MRI) at 30° and 50° knee flexion before OWHTO and after hardware removal were included. 3D computer models of the knee were created from the MRI scans and superimposed over the images taken in each position using voxel-based registration. For patellar height evaluation, a patellar reference point was established at each flexion angle and the femoral condylar planes (FCP) were set, including the transepicondylar axis. The patellar center angle was defined as the angle between an FCP that included the top of the intercondylar notch and an FCP that included the patellar reference point. The patellar center angle was evaluated at 30° and 50° knee flexion before and after OWHTO. RESULTS: The patellar center angle at 30° and 50° knee flexion did not significantly decrease after OWHTO, whereas the Caton-Deschamps index and Blackburne-Peel index based on tibia-referenced measurements significantly decreased postoperatively. CONCLUSION: Patellar height position relative to the femur in the 3D computer model did not decrease after OWHTO, whereas tibia-referenced conventional radiographic measurements significantly decreased. When evaluating patellar height, characteristics of each parameter should be considered.

Factors Associated with Postoperative Knee Joint Line Obliquity After Medial Open Wedge High Tibial Osteotomy.

BACKGROUND: There are still few reports on factors associated with postoperative knee joint line obliquity (KJLO). PURPOSE: The purpose was to determine preoperative radiographic factors that are associated with KJLO postoperatively after open wedge high tibial osteotomy (OWHTO) using multivariable linear regression analysis and multivariable logistic regression analysis. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A total of 60 patients with 65 varus knees who underwent OWHTO between December 2012 and June 2018 at a single institution were retrospectively enrolled in this study. The authors evaluated radiologic parameters including the weightbearing line ratio, femorotibial angle, medial proximal tibial angle, mechanical lateral distal femoral angle (LDFA), lateral distal tibial angle, joint line convergence angle (JLCA), KJLO, and ankle joint obliquity. They also categorized these radiographic parameters as preoperative and postoperative and calculated the difference (Δ) between preoperative and postoperative values. To determine which of the radiographic parameters were most associated with postoperative KJLO, multivariable linear regression analysis was performed using the stepwise method. Multivariable logistic regression analysis was used to examine the relative contribution of the preoperative radiographic parameters to an abnormal postoperative KJLO (>4°). RESULTS: In the multivariable linear regression analysis, the preoperative LDFA and JLCA showed a statistically significant correlation. Multivariable logistic regression analysis revealed that the mean preoperative LDFA was significantly larger in the group with abnormal KJLO than in the group with the control group (odds ratio, 1.84; 95% CI, 1.12-3.02; P = .02), while preoperative JLCA tended to be larger in the abnormal KJLO group than the control group but not statistically significantly different. CONCLUSION: KJLO after OWHTO was associated with preoperative LDFA and JLCA in multivariable linear regression analysis, and preoperative LDFA was the most important factor associated with abnormal KJLO after OWHTO in multivariable logistic regression analysis.

Abrasion arthroplasty promotes improvement of degenerated femoral trochlear cartilage after medial open wedge high tibial osteotomy.

OBJECTIVES: Several studies have reported negative effects of open wedge high tibial osteotomy (OWHTO) on patellofemoral joints with cartilage degeneration and recommended performing other procedures. However, if chondral resurfacing surgery could promote improvement of cartilage degeneration in the patellofemoral joint, OWHTO would be an acceptable option. The purposes of this study were to arthroscopically evaluate the femoral trochlear articular cartilage after abrasion arthroplasty combined with OWHTO and to investigate the factors promoting improvement of that cartilage. METHODS: The present study cohort comprised 18 knees of 18 patients with varus osteoarthritis of the knee who had (1) International Cartilage Repair Society (ICRS) grade 4 femoral trochlear chondral lesions at the time of OWHTO; (2) undergone abrasion arthroplasty of the femoral trochlear cartilage in combination with OWHTO; (3) undergone second-look arthroscopy; and (4) been followed up for more than 2 years. Cartilage status was arthroscopically graded at the time of OWHTO and second-look arthroscopy. Patients were allocated to two groups according to the status of the femoral trochlear cartilage at the time of second-look arthroscopy: the improved group comprised patients with an ICRS grade of less than 3, and the not improved group comprised those with an ICRS grade of 4. Clinical outcomes, expressed as Knee Injury and Osteoarthritis Outcome Score (symptoms, pain, activities of daily living, function in sports/recreation and quality of life) and selected radiographic variables were compared between the two groups. RESULTS: There were 11 (61%) knees in the improved group and 7 (39%) in the not improved group. A comparison of radiographic variables between the two groups revealed that neither limb alignment nor patellar height affected cartilage changes. The two groups had similar results on the symptoms, pain, sports/recreation and activities of daily living subscales of the Knee Injury and Osteoarthritis Outcome Score. However, the quality of life subscale significantly differed between the two groups (p=0.025). CONCLUSION: Degenerated femoral trochlear cartilage can improve after combined abrasion arthroplasty and OWHTO. A comparison of clinical outcomes between the improved and not improved groups revealed that neither radiographic variables nor clinical symptoms, including pain, affected cartilage changes at short-term follow-up. LEVEL OF EVIDENCE: Case series, level V.

Anterior tibial loading on the calf enhances anterior tibial translation in the anterior cruciate ligament deficient knee in the anterior gravity radiographic view.

BACKGROUND: Lateral radiograph in the prone position with the knee flexed at 15° (anterior gravity view (AGV)) is useful as a screening for anterior cruciate ligament (ACL) injuries, while it is sometimes difficult to find the side-to-side difference (SSD) in anterior tibial translation. Thus, we applied a weight (three kilograms) around the lower leg to increase anterior tibial translation. We aimed to determine whether weight load confers an advantage in visualizing anterior knee laxity in ACL injuries. METHODS: Fifty-eight patients with confirmed unilateral ACL tears from February 2012 to April 2014 had consented to participate in this study. Lateral radiographs for both knees were taken in AGV and in AGV with a three-kilogram weight load applied to the proximal lower leg. Then, the SSD of tibial position related to the femur was measured in these radiographs. RESULTS: The SSD with the weight was significantly greater than that without the weight (5.9 ± 2.1 and 3.5 ± 1.6 mm, respectively, p < 0.01). The ratio of patients with SSD of three millimeters or more in AGV with the weight was also significantly larger than that without the weight (p < 0.01). CONCLUSIONS: The anterior laxity in AGV with the three-kilogram weight is larger than that without the weight. Thus, the AGV with the weight could be one of the helpful radiographic technique for auxiliary diagnosis of ACL injury. Level of evidence Cohort study, Level IV.

Ultrasonographic Evaluation of the Early Healing Process After Achilles Tendon Repair.

BACKGROUND: Little is known about early healing of repaired Achilles tendons on imaging, particularly up to 6 months postoperatively, when patients generally return to participation in sports. PURPOSE: To examine changes in repaired Achilles tendon healing with ultrasonography for up to 12 months after surgery. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Ultrasonographic images of 26 ruptured Achilles tendons were analyzed at 1, 2, 3, 4, 6, and 12 months after primary repair. The cross-sectional areas (CSAs) and intratendinous morphology of the repaired tendons were evaluated using the authors' own grading system (tendon repair scores), which assessed the anechoic tendon defect area, intratendinous hyperechoic area, continuity of intratendinous fibrillar appearance, and paratendinous edema. RESULTS: The mean ratios (%) of the CSA for the affected versus unaffected side of repaired Achilles tendons gradually increased postoperatively, reached a maximum (632%) at 6 months, and then decreased at 12 months. The mean tendon repair scores increased over time and reached a plateau at 6 months. CONCLUSION: Ultrasonography is useful to observe the intratendinous morphology of repaired Achilles tendons and to provide useful information for patients who wish to return to sports. Clinical parameters such as strength, functional performance, and quality of healed repaired tendons should also be assessed before allowing patients to return to sports.

Safety of autologous bone marrow-derived mesenchymal stem cell transplantation for cartilage repair in 41 patients with 45 joints followed for up to 11 years and 5 months.

Among autologous somatic stem cells, bone marrow-derived mesenchymal stem cells (BMSCs) are the most widely used worldwide to repair not only mesenchymal tissues (bone, cartilage) but also many other kinds of tissues, including heart, skin, and liver. Autologous BMSCs are thought to be safe because of the absence of immunological reaction and disease transmission. However, it is possible that they will form tumours during long-term follow-up. In 1988, we transplanted autologous BMSCs to repair articular cartilage, which was the first such trial ever reported. Subsequently we performed this procedure in about 40 patients. Demonstration that neither partial infections nor tumours appeared in these patients provided strong evidence for the safety of autologous BMSC transplantation. Thus, in this study we checked these patients for tumour development and infections. Between January 1998 and November 2008, 41 patients received 45 transplantations. We checked their records until their last visit. We telephoned or mailed the patients who had not visited the clinics recently to establish whether there were any abnormalities in the operated joints. Neither tumours nor infections were observed between 5 and 137 (mean 75) months of follow-up. Autologous BMSC transplantation is a safe procedure and will be widely used around the world.

The location-specific healing response of damaged articular cartilage after ACL reconstruction: short-term follow-up.

Although many different interventions have been proposed for treating cartilage lesions at the time of ACL reconstruction, the normal healing response of these injuries has not been well documented. To address this point, we compared the arthroscopic status of chondral lesions at the time of ACL reconstruction with that obtained at second-look arthroscopy. We hypothesized that there might be a location-specific difference in the healing response of damaged articular cartilage. Between September 1998 and March 2000, 383 patients underwent arthroscopically-assisted hamstring ACL reconstruction without any intervention to the articular cartilage. Among these patients, 84 patients underwent second-look arthroscopy (ranging from 6 to 52 months following initial surgery) and make up the population of the present study. Chondral injuries, left untreated at ACL reconstruction, were arthroscopically evaluated using the Outerbridge classification, and were again evaluated at second-look arthroscopy. At second-look arthroscopy, there was significant recovery of chondral lesions by Outerbridge grading on both the medial and lateral femoral condyles. Among the recovered chondral lesions, 69% of cases of the medial femoral condyle, 88% of cases of the lateral femoral condyle were partial thickness injuries (grade I and II). Conversely, there was no significant recovery of chondral lesions observed at the patello-femoral joint or tibial plateaus. Our study revealed that there was a location-specific difference in the natural healing response of chondral injury. Untreated cartilage lesions on the femoral condlyes had a superior healing response compared to those on the tibial plateaus, and in the patello-femoral joint.

Medial marginal fracture of the patella following patellar dislocation.

Among patients with patellar dislocation, a small fragment is occasionally found along the medial border of the patella. However, the detailed pathology of this fracture has not been clearly described, especially in relation to the medial patellofemoral ligament (MPFL). The purpose of this study was to describe the pathology of this fracture in relation to the MPFL. The subjects were seven patients with an acute primary patellar dislocation showing a medial marginal fracture of the patella. An open exploration was performed to confirm the relationship between the fragment and the MPFL. The MPFL was repaired by re-attachment to the patella with anchors. The patellar fracture site was determined by the location of anchors in the post-operative plain radiograph. The fragments were continuous with the thick and taut MPFL in all cases. Re-attachment of the MPFL stabilized the patella against lateral shift by manual force improving the tracking. All patients returned to their pre-injury activity level without any episodes of recurrent dislocation or subluxation at the final follow up (av. 31 months). Medial marginal fracture of the patella was an avulsion fracture of the MPFL that occurred at the middle one-third of the patella.

Bi-socket ACL reconstruction using hamstring tendons: high versus low femoral socket placement.

To clarify the importance of the femoral socket location in bi-socket Anterior cruciate ligament (ACL) reconstruction. Subjects included 261 patients with an average age of 26 years who received ACL reconstruction via the high-femoral socket procedure (Group H) and 43 patients with an average age of 29 years who received ACL reconstruction via the low-femoral socket procedure (Group L) with a minimal follow-up of 24 months. In Group H, the femoral sockets were created at 1:00 or 11:00 and 2:00-2:30 or 9:30-10:00 of the intercondylar notch. In Group L, the two femoral sockets were drilled at 2:00 or 10:00 and 3:00 or 9:00. For the tibial side, a single tunnel was made at the center of the footprint. Evaluation was performed based on the IKDC Knee Examination Form. While 137 knees (52%) were graded as normal, 100 (38%) as nearly normal, 8 (3%) as abnormal, and 2 (1%) as severely abnormal with 14 (5%) re-injury in Group H, 38 knees (74%) were graded as normal, and 7 (16%) as nearly normal with 3 (7%) re-injury in Group L, showing a better subjective evaluation (P = 0.007). The average side-to-side differences in anterior laxity at manual maximum force with the KT-1000 were 1.1 +/- 1.6 mm for Group H and 1.0 +/- 1.6 mm for Group L without statistically significant differences excluding re-injured cases. There were 204 patients (83%) from Group H and 33 (83%) from Group L with values between -2 and 2 mm, while 228 (92%) patients from Group H and 38 (95%) from Group L had values distributed between -3 and 3 mm. While the bi-socket ACL reconstruction provided objectively satisfactory clinical outcomes in more than 90% of the patients, the low-femoral socket placement was found to subjectively achieve better outcomes.

Changes in cross-sectional area of hamstring anterior cruciate ligament grafts as a function of time following transplantation.

PURPOSE: To measure the cross-sectional area (CSA) of hamstring anterior cruciate ligament (ACL) grafts in humans up to 2 years postoperatively and to estimate the appropriate graft-notch distance (the distance between ACL graft and roof or wall of the notch) at surgery. TYPE OF STUDY: Case series. METHODS: Fifty-nine patients, who had consented to have a magnetic resonance imaging (MRI) evaluation postoperatively, underwent endoscopic ACL reconstruction using 3- to 5-strand autogenous hamstring tendons. Intraoperatively, the CSA of the graft was measured using a custom-made area micrometer. Postoperatively, 115 axial MRIs of the grafts (48 at 3 months, 44 at 12 months, and 23 at 24 months) were obtained. They were transmitted to a personal computer and the CSAs of the grafts' midsubstance were calculated. To evaluate the accuracy of the MRI measurement, another 15 patients who consented to have MRI 2 days after surgery were selected and intraoperative graft CSA measurements and graft axial MRI were performed 2 days after surgery. RESULTS: The CSAs of the grafts measured by MRI 2 days after surgery were well correlated with those directly measured intraoperatively (gamma = 0.905). The CSA of the grafts measured intraoperatively was 43 +/- 5 mm2, and those estimated by MRI at 3, 12, and 24 months were 50 +/- 9 mm2, 54 +/- 9 mm2, and 48 +/- 12 mm2, respectively. The increase in graft diameter at 3, 12, and 24 months was 9% +/- 8%, 13% +/- 10%, and 7% +/- 12%, respectively. CONCLUSIONS: In humans, the increase in CSA of the ACL graft was smaller compared with previous animal studies. The graft CSA increased up to 29% (13% in diameter) 12 months after surgery. When a 95% confidence interval was used, the percent increase in diameter of the reconstructed graft was estimated to be less than 32% in 95% of the cases. When the graft diameter was 7, 8, or 9 mm, a 1.1-, 1.3-, or 1.4-mm graft-notch distance, respectively, was suitable for impingement-free graft during postoperative periods with 95% of probability. LEVEL OF EVIDENCE: Level IIII.

Autologous bone marrow stromal cell transplantation for repair of full-thickness articular cartilage defects in human patellae: two case reports.

This study assessed the effectiveness of autologous bone marrow stromal cell transplantation for the repair of full-thickness articular cartilage defects in the patellae of a 26-year-old female and a 44-year-old male. These two patients presented in our clinic because their knee pain prevented them from walking normally. After thorough examination, we concluded that the knee pain was due to the injured articular cartilage and decided to repair the defect with bone marrow stromal cell transplantation. Three weeks before transplantation, bone marrow was aspirated from the iliac crest of each patient. After erythrocytes had been removed by use of dextran, the remaining nucleated cells were placed in culture. When the attached cells reached subconfluence, they were passaged to expand in culture. Adherent cells were subsequently collected, embedded in a collagen gel, transplanted into the articular cartilage defect in the patellae, and covered with autologous periosteum. Six months after transplantation, clinical symptoms (pain and walking ability) had improved significantly and the improvement has remained in effect (5 years and 9 months posttransplantation in one case, and 4 years in the other), and both patients have been satisfied with the outcome. As early as 2 months after transplantation, the defects were covered with tissue that showed slight metachromatic staining. Two years after the first and 1 year after the second transplantation, arthroscopy was performed and the defects were repaired with fibrocartilage. Results indicate autologous bone marrow stromal cell transplantation is an effective approach in promoting the repair of articular cartilage defects.

Second-look arthroscopy of anterior cruciate ligament grafts with multistranded hamstring tendons.

PURPOSE: The purpose of this study was to clarify the fate of intra-articularly transplanted multistranded hamstring tendon grafts used for anterior cruciate ligament (ACL) reconstruction. TYPE OF STUDY: Consecutive samples. METHODS: The subjects were 153 patients (156 knees) with a mean age of 24 years, who had been evaluated as experiencing clinical success. The patients consented to undergo second-look arthroscopy after ACL reconstruction with multistranded autogenous hamstring tendon grafts at 5 to 51 months previously. Ninety-six knees were surgically treated with the single-socket procedure, and the remaining 60 were treated with the bisocket procedure. None of the patients complained of instability of the index knee. The mean side-to-side difference at manual-maximum force in anterior displacement by KT-1000 on 107 patients was 1.2 +/- 1.1 mm (-1 to 4 mm). Arthroscopic evaluation was performed focusing on tension and thickness dividing into 3 groups based on the postoperative period. The chi-square and Mann-Whitney U tests were used for statistical analysis. RESULTS: A total of 139 grafts (89%) were evaluated as taut and 17 (11%) as mildly lax or lax. Fifty-three (34%) showed some partial tear, and the other 103 (66%) appeared thick without partial tear. The percentage of mildly lax or lax grafts in the group of patients older than 2 years was higher than that in patients younger than 1 year, and no significant difference was found among the groups in the percentage of partially torn grafts. The patients with mildly lax or lax grafts showed statistically higher KT values, while those with partially torn grafts did not. No statistically significant difference was seen in any of these findings between the 2 procedures, although the bisocket procedure tended to show better tension or thickness. CONCLUSIONS: Arthroscopically, 11% of the hamstring ACL grafts showed looseness and 34% had partial tear in the clinically successful knees. LEVEL OF EVIDENCE: Level IV in therapeutic studies investigating the results of treatment.

Acute grade III medial collateral ligament injury of the knee associated with anterior cruciate ligament tear. The usefulness of magnetic resonance imaging in determining a treatment regimen.

BACKGROUND: The appropriate management of acute grade III medial collateral ligament injury when it is combined with a torn anterior cruciate ligament has not been determined. HYPOTHESIS: Magnetic resonance imaging grading of grade III medial collateral ligament injury in patients who also have anterior cruciate ligament injury correlates with the outcome of their nonoperative treatment. STUDY DESIGN: Prospective cohort study. METHODS: Seventeen patients were first treated nonoperatively with bracing. Eleven patients with restored valgus stability received anterior cruciate ligament reconstruction only, and six with residual valgus laxity also received medial collateral ligament surgery. RESULTS: Magnetic resonance imaging depicted complete disruption of the superficial layer of the medial collateral ligament in all 17 patients and disruption of the deep layer in 14. Restoration of valgus stability was significantly correlated with the location of superficial fiber damage. Damage was evident over the whole length of the superficial layer in five patients, and all five patients had residual valgus laxity despite bracing. Both groups had good-to-excellent results 5 years later. CONCLUSIONS: Location of injury in the superficial layer may be useful in predicting the outcome of nonoperative treatment for acute grade III medial collateral ligament lesions combined with anterior cruciate ligament injury.

Prediction of reparability of isolated semilunar lateral meniscus tears by magnetic resonance imaging.

Sixty-one menisci in 60 patients who underwent preoperative MRI and subsequent arthroscopic operation for symptomatic isolated semilunar lateral meniscus tears were evaluated. The MRI criterion of reparability was the presence of a longitudinal or oblique high signal intensity line within 3 mm meniscosynovial junction without a high signal intensity area in the meniscal body, and the criterion of irreparability was high signal intensity line greater than 5 mm from the meniscosynovial junction and/or abnormal high intensity area in the meniscal body. Perioperatively the menisci were repaired for longitudinal unstable tears located at the outer one-half and were excised for other type of tears. Consequently 30 menisci were repaired, and 31 menisci underwent menisectomy. Overall, MRI was useful for detecting the meniscus tears in 42 (69%). The accuracy and sensitivity of MRI in predicting reparability were 91% and 33%; for predicting irreparability the respective values were 90% and 90%. The findings of this retrospective study suggest that MRI is not always useful in predicting reparability of the symptomatic isolated lateral semilunar meniscus tears, and that the most symptomatic cases with normal MRI are reparable.

Evaluation of active knee flexion and hamstring strength after anterior cruciate ligament reconstruction using hamstring tendons.

PURPOSE: The purpose of this study was to evaluate active knee flexion range of motion and hamstring strength following hamstring anterior cruciate ligament (ACL) reconstruction. TYPE OF STUDY: Case control study, consecutive sample. METHODS: Seventy-four consecutive patients who had undergone hamstring ACL reconstruction underwent isokinetic muscle strength testing at 2 years post surgery. Measurements of the maximum standing active knee flexion angle with the hip extended were also taken. During isokinetic testing, we evaluated flexion torque at 90 degrees of knee flexion, in addition to the peak flexion torque. We further compared these parameters of muscle strength around the knee for the patients in whom only semitendinosus tendon was harvested as a graft source (ST group), and those from whom the semitendinosus tendon and the gracilis tendon were harvested (ST/G group). RESULTS: Isokinetic testing showed that, in both the ST and ST/G groups, the knee flexor strength of the involved leg was less effectively restored at 90 degrees of knee flexion than at the angle at which the peak torque was generated. Conversely, no significant difference was seen in the side-to-side ratio in either the peak flexion torque or the 90 degrees flexion torque between the groups. The side-to-side ratio in mean maximum standing knee flexion angle was significantly lower in the ST/G group than in the ST group. CONCLUSIONS: This study suggests that the loss of knee flexor strength following the harvest of the hamstring tendons may be more significant than has been previously estimated. Furthermore, multiple tendon harvest may affect the range of active knee flexion.

Subchondral microfracture of the knee without osteonecrosis after arthroscopic medial meniscectomy.

We report a case of an osteonecrosis-like lesion of the knee that developed shortly after an arthroscopic medial meniscectomy. Clinical presentation, physical findings, and imaging of the knee including magnetic resonance imaging were similar to those of the cases that have been reported as osteonecrosis after meniscectomy. However, histologic analysis of the lesion revealed that there was no osteonecrosis but rather a subchondral microfracture with active callus formation.