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.

Anatomical rectangular tunnel anterior cruciate ligament reconstruction provides excellent clinical outcomes.

PURPOSE: The purpose of this study was to prospectively evaluate the clinical outcomes following anatomical rectangular tunnel anterior cruciate ligament (ACL) reconstruction with a bone-patellar tendon-bone (BTB) graft using an adjustable-length femoral cortical fixation device with enough patients and a high follow-up rate. METHODS: This study included 125 patients who underwent anatomical rectangular tunnel ACL reconstruction with a BTB graft. A BTB TightRope® was used for femoral graft fixation. Clinical evaluations were performed more than 2 years after surgery using the International Knee Documentation Committee (IKDC) Form. Patients interviewed by telephone were only subjectively evaluated. The side-to-side difference in anterior laxity at a manual maximum force was measured using the KT-2000 Arthrometer®. RESULTS: Among the 125 patients, 99 were ultimately included and 26 were lost to follow-up (follow-up rate: 79%). Eight patients had re-tear (re-tear rate: 8%) and six patients had ACL injuries to the contralateral knee. Three patients did not follow our rehabilitation programme. One patient suffered septic arthritis. These 18 patients were considered ineligible for clinical evaluations. Therefore, clinical evaluations were performed in 81 of the 99 patients (64 were available for direct follow-up and 17 were available for a telephone interview). The follow-up period was 30 ± 10 months (range 24-68 months). According to the IKDC subjective assessment, 48 (59%) and 33 (41%) knees were graded as normal and nearly normal, respectively. A loss of extension (3°-5°) was observed in five patients (8%), whereas one patient (2%) exhibited a loss of flexion (3°-5°). The Lachman test was negative in 63 patients (98%). The pivot shift test was negative in 59 patients (92%). The side-to-side difference in KT value was 0.4 ± 0.7 mm (range - 1-4 mm). CONCLUSION: Anatomical rectangular tunnel ACL reconstruction with a BTB graft using an adjustable-length femoral cortical fixation device provided excellent clinical outcomes both subjectively and objectively more than 2 years after surgery, whereas 8 of the 99 patients had re-tear of the graft. The adjustable-length femoral cortical fixation device could be safely used in anatomical rectangular tunnel ACL reconstruction with a BTB graft. LEVEL OF EVIDENCE: III.

Shoulder and elbow evaluation of pitchers in National High School Baseball Invitational Tournaments and National High School Baseball Championships from 1993 to 2016 in Japan.

BACKGROUND: Shoulder and elbow examinations for pitchers have been performed in Japan's National High School Baseball Invitational Tournaments (NHSBITs) and National High School Baseball Championships (NHSBCs) since 1993. However, for years the results have not been analyzed. The purpose of this study was to evaluate changes in the condition of shoulders and/or elbows of pitchers from 1993 to 2016. MATERIALS AND METHODS: Pitchers in NHSBITs and NHSBCs, 1994-2016, were examined together with those who received a trial examination (Trial) in the NHSBC 1993. Shoulder and elbow symptoms were comprehensively graded into five categories; none, mild, moderate, severe and dysfunction. Standard plain radiographs of the shoulder and elbow were obtained. Average Annual Percent Changes (AAPCs) in the percentages of pitchers with symptoms and positive radiographic findings were analyzed. RESULTS: The percentages of pitchers with moderate or worse symptoms in the shoulder or elbow were 14.6% and 13.8%, respectively, in the Trial, 1.1% and 1.1% in NHSBITs and 1.3% and 2.0% in NHSBCs. The AAPC of pitchers with a symptomatic shoulder in NHSBITs was reduced over the study period, at -3.36% (P < 0.05), but that in NHSBCs was unchanged at -1.01%. The AAPCs of pitchers with a symptomatic elbow in NHSBITs and in NHSBCs decreased, at -3.13% and -3.33%, respectively (P < 0.05), while that of pitchers with residual apophyseal fragmentation at the ulnar collateral ligament insertion increased at +2.79% (P < 0.05). The decreased percentages of symptomatic pitchers suggest that joint condition is well controlled in high school days; however, the increased frequency of radiographic findings suggests the necessity of protection against overuse in younger players. CONCLUSIONS: The percentages of pitchers with symptomatic shoulders and elbows in NHSBITs and those with symptomatic elbows in NHSBCs have decreased over the 23 years. However, the increased frequency of residual medial humeral epicondyle apophyseopathy should be noted.

Loop Length Change of an Adjustable-Length Femoral Cortical Suspension Device in Anatomic Rectangular Tunnel Anterior Cruciate Ligament Reconstruction With a Bone-Patellar Tendon-Bone Graft and Associated Clinical Outcomes.

PURPOSE: To evaluate loop length changes of an adjustable femoral cortical suspensory fixation device and assess the clinical results after anatomic rectangular tunnel anterior cruciate ligament (ART-ACL) reconstruction with a bone-tendon-bone (BTB) graft. METHODS: The study included 50 patients who underwent ART-ACL reconstruction with a BTB graft fixed using the adjustable-length device BTB TightRope for femoral fixation between July 2013 and December 2014. Computed tomography examinations were performed at 1 and 12 weeks after the surgery. Loop length was measured in the reconstructed plane just parallel to the femoral tunnel, including the bone plug and the button. Measurement was performed thrice, and the mean value was used. Loop length change was defined as the difference in loop length between 1 and 12 weeks after the surgery. A paired t test was conducted with the effect size for statistical analysis. At 2 years postoperatively, clinical evaluations, including subjective and objective assessments, were performed. RESULTS: The mean loop lengths at 1 and 12 weeks were 25.77 ± 3.88 mm and 25.81 ± 3.89 mm, respectively, with a significant difference (P = .01). However, the effect size was 0.01, suggesting that the difference was not meaningful. The mean individual loop length change was 0.04 ± 0.13 mm. All individual loop length changes were within the measurement error range. At 2 years postoperatively, 49 patients (98%) were graded as normal or nearly normal according to the International Knee Documentation Committee form. The mean side-to-side difference in anterior laxity at manual maximum force was 0.2 ± 0.5 mm. CONCLUSIONS: The loop length change of an adjustable-length femoral cortical suspension device was negligible after ART-ACL reconstruction with a BTB graft. This ART-ACL reconstruction with a BTB graft using an adjustable-length device could safely provide sufficient stability to the operated knee. LEVEL OF EVIDENCE: Level Ⅳ, therapeutic case series.

Outcome of anatomical double-bundle ACL reconstruction using hamstring tendons via an outside-in approach.

PURPOSE: To evaluate the clinical outcome of anatomical double-bundle anterior cruciate ligament (ACL) reconstruction using multistranded hamstring tendons via an outside-in approach. METHODS: One hundred and twenty-one patients (mean age 28 ± 10 years) who underwent ACL reconstruction were examined. Using an outside-in femoral drill guide, an upper femoral tunnel for the anteromedial (AM) graft was created just below the superior articular cartilage margin of the medial wall of the lateral condyle through a small incision. A lower femoral tunnel for the posterolateral (PL) graft was drilled in the centre of the inferior-posterior half of the attachment area behind the resident's ridge in the same manner. Two tibial tunnels were created at the centre of the AM and PL bundle footprints of a normal ACL. Patients were evaluated at 24 months postoperatively. RESULTS: According to the IKDC form, 52 knees (43 %) were graded as normal, 64 (53 %) as nearly normal, 1 (1 %) as abnormal and 4 (3 %) as graft rupture due to re-injury. Loss of knee extension of <5° was observed in one patient (1 %). Among 111 patients who were directly evaluated, none showed loss of flexion of <5°. Lachman sign was negative in 103 patients (93 %), while the pivot shift test result was negative or equivalent to that of the contralateral healthy knee in 103 patients (93 %). The mean side-to-side difference in anterior laxity at manual maximum force with the KT-2000 arthrometer(®) was 0.9 ± 1.1 mm, and 94 % of patients showed a range between -1 and +2 mm. CONCLUSION: The anatomical double-bundle outside-in ACL reconstruction provided a satisfactory short-term outcome. LEVEL OF EVIDENCE: Case series, Level IV.

The effect of cortical button location on its post-operative migration in anatomical double-bundle anterior cruciate ligament reconstruction.

PURPOSE: To investigate the effect of EndoButton (Smith & Nephew Endoscopy, Andover, MA, USA) location on post-operative migration in anterior cruciate ligament (ACL) reconstruction. METHODS: Seventy-seven patients underwent anatomical double-bundle ACL reconstruction using EndoButtons. Comparing patient radiographs immediately post-operatively with those at 1 year, migration was defined when EndoButtons moved more than 1 mm or rotated over 5°. Initial location of EndoButtons was evaluated on radiographs immediately post-operatively. We measured distances from the EndoButton to the posterior and distal edge of the femur (D1, D2) on lateral radiographs and distances from the EndoButton to the lateral and distal edge of the femur (D3, D4) on anteroposterior radiographs. The relationship between supracondylar line and the ratio of migration was also investigated. RESULTS: D1 in the migrated group were significantly lower than those in the non-migrated group (11.8 ± 12.7 vs. 16.0 ± 10.2 mm). D2, D3 and D4 were not of significant difference in the two groups. The ratio of migration in the area posterior to the supracondylar line was significantly higher than that in the anterior area (54.3 vs. 15.1%). CONCLUSION: EndoButtons, which was located distally and posteriorly, especially in the area posterior to the lateral supracondylar line, migrated more frequently, although migration of the button had no effect on the clinical parameters evaluated in this study. CLINICAL RELEVANCE: It is preferable to settle EndoButton anteriorly to the lateral supracondylar line in order to avoid its migration for the graft tension due to our findings about the relationship between initial location of EndoButton and the rate of migration. LEVEL OF EVIDENCE: Prognostic case series, Level IV.

Patellofemoral chondral status after medial patellofemoral ligament reconstruction using second-look arthroscopy in patients with recurrent patellar dislocation.

BACKGROUND: Most patients with recurrent patellar dislocation show cartilage damage in the patellofemoral joint. Medial patellofemoral ligament reconstruction has become one of the most important surgical techniques for treating recurrent patellar dislocation. However, patellofemoral chondral status after this reconstruction has not been elucidated. The purpose of this study was to investigate the effects of medial patellofemoral ligament reconstruction on articular cartilage in the patellofemoral joint by comparing the arthroscopic chondral status at the time of reconstruction with that at second-look arthroscopy. METHODS: Participants in the present study comprised 31 patients (22 females, 9 males; 32 knees) who underwent second-look arthroscopy at a median of 12 months (range 6-40 months) after dual tunnel medial patellofemoral ligament reconstruction using a double-looped autologous semitendinosus tendon graft. Median age at the time of initial surgery was 20 years (range 13-43 years). The patellofemoral joint was divided into six portions, comprising the medial facet of the patella, central ridge, lateral facet of the patella, anterior medial femoral condyle, femoral groove, and anterior lateral femoral condyle. Chondral status in each portion according to the International Cartilage Repair Society classification was retrospectively evaluated at the time of initial surgery and second-look arthroscopy. RESULTS: Before medial patellofemoral ligament reconstruction, chondral lesions were observed in the patellofemoral joint in 31 knees (97%). At the central ridge of the patella, chondral damage was observed in 22 knees (69%) at initial surgery and damaged cartilages showed recovery in 6 knees. No significant difference in the alteration of chondral status was seen for the medial facet, lateral facet of the patella, anterior medial femoral condyle, femoral groove, and anterior lateral femoral condyle. CONCLUSIONS: According to short-term results, the patellofemoral chondral status after medial patellofemoral ligament reconstruction was not altered at second-look arthroscopy in most part of patellofemoral joint. At the central ridge of the patella, significant improvement of the International Cartilage Repair Society grading was observed.

Glenoid rim morphology in young athletes with unstable painful shoulders: primarily painful vs. frankly unstable.

Background: To investigate the characteristics of glenoid rim morphology in young athletes (<40 yr) with unstable painful shoulder. Methods: This was a retrospective case series. The inclusion criteria were as follows: (1) shoulder pain during sports activity, (2) traumatic onset, (3) no complaint of shoulder instability, and (4) soft tissue or bony lesions confirmed on imaging examinations (computed tomography and magnetic resonance imaging). The above-mentioned painful cohort was then compared (in a 2:1 ratio) to a match-paired control group of patients with similar demographics but with frank anterior glenohumeral instability as defined by imaging and physical findings. The pain (not apprehension) was reproduced during the anterior apprehension test in supine position and relieved by relocation test in all patients. Glenoid rim morphology, bone union in shoulders with a fragment-type glenoid, glenoid defect size, bone fragment size, medial displacement of bone fragments (MDBF), and medial distance of erosion (MDE) were compared between painful shoulders and unstable shoulders. Results: There were 79 painful shoulders and 165 unstable shoulders. The glenoid rim morphology was normal in 33 shoulders, erosion-type in 15 shoulders, and fragment-type in 31 shoulders among painful shoulders, whereas the respective shoulders were 19, 33, and 113 among unstable shoulders (P < .001). Bone union was complete in 15 shoulders, partial in 14 shoulders, and nonunion in 2 shoulders among painful shoulders, whereas the respective shoulders were 43, 31, and 39 among unstable shoulders (P = .001). The mean glenoid defect size was 6.0 ± 7.2% and 12.7 ± 7.4%, respectively (P < .001), and the mean bone fragment size was 5.8 ± 6.4% and 5.4 ± 4.6%, respectively, (P = .591). The mean MDBF was 1.4 ± 1.5 mm and 3.0 ± 2.2 mm, respectively (P < .001), and the mean MDE was 2.3 ± 1.2 mm and 5.2 ± 2.4 mm, respectively (P < .001). In shoulders with a smaller glenoid defect (<13.5%), the prevalence of shoulders with MDBF (<2 mm) and shoulders with MDE (<2 mm) was more frequent in painful shoulders. On the other hand, in shoulders with a larger glenoid defect (≥13.5%), erosion-type glenoid, nonunion in fragment-type glenoid and bone fragment smaller than 7.5% was not recognized in painful shoulders. Shoulders with MDBF (<2 mm) were significantly more frequent in painful shoulders (P = .009). Conclusions: In painful shoulders normal or erosion-type glenoid was predominant, and glenoid defect size was significantly smaller than unstable shoulders. On the other hand, a large bone fragment (≥7.5%) remained and united completely or partially in all shoulders with a larger glenoid defect (≥13.5%). Bone union was obtained within 2 mm from the articular surface in most of them.

Anterior impingement test for labral lesions has high positive predictive value.

BACKGROUND: The anterior impingement test is intended to detect anterosuperior acetabular labral lesions. In patients treated for labral lesions its sensitivity is reportedly 95% to 100%, and in a small group of patients undergoing periacetabular osteotomy, its sensitivity was 59% and specificity 100%. However, the sensitivity, specificity, positive predictive value, and negative predict value of this test to detect these labral lesions in unselected patients with hip pain are unknown. QUESTIONS/PURPOSES: We investigated these four parameters (1) in unselected patients with hip pain, and (2) in three subgroups of patients with dysplasia, femoroacetabular impingement (FAI), and with an intact joint space. METHODS: We prospectively studied 69 patients (15 men and 54 women) with a mean age of 57.2 years (range, 27-81 years). One observer performed the anterior impingement test in all patients. We determined the presence or absence of an anterosuperior labral lesion with radial MRI in 107 hips (38 patients in both hips: 14 with pain, and 24 without pain). We also investigated the parameters in the three subgroups which consisted of 60 cases of dysplasia, 27 cases of FAI, and 80 cases with intact joint space; the third subgroup partially overlapped the first and second subgroups. RESULTS: The four parameters in all hips were 50.6% (45/89), 88.9% (16/18), 95.7% (45/47), and 26.7% (16/60), respectively. Parameters in the three subgroups were similar to those of all cases. CONCLUSIONS: Although the sensitivity of the anterior impingement test did not reach a sufficient level for detecting anterosuperior labral lesions, we believe the high positive predictive value makes the test useful. LEVEL OF EVIDENCE: Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Effects of medial patellofemoral ligament reconstruction on patellar tracking.

PURPOSE: Medial patellofemoral ligament (MPFL) reconstruction has been performed to treat recurrent patellar dislocation. However, the effects on patellar tracking have not been well documented, particularly in patients. The purpose of this study is to compare patellar tracking pattern and chondral status at MPFL reconstruction with those at second-look arthroscopy. METHODS: Between 1999 and 2008, 71 patients with recurrent patellar dislocation underwent MPFL reconstruction using a double-looped semitendinosus tendon. Of these, 25 knees in 24 patients underwent second-look arthroscopy (at 6-26 months after initial surgery), forming the subject for the present study. No other surgical procedures such as tibial tuberosity transfer, lateral release, or osteotomy were performed in any patients. To assess the patellar tracking pattern, the position of the patella on femoral groove was evaluated arthroscopically during passive knee motion through lateral suprapatellar portal. RESULTS: Before MPFL reconstruction, the patella in all patients was shifted laterally throughout the entire range of knee motion. Immediately after MPFL reconstruction, patellar malalignment was corrected in all cases. On second-look arthroscopy, two different patellar tracking patterns were observed. In 9 knees, the patella was located on the center of the femoral groove throughout the range of motion. Meanwhile, in the remaining 16 knees, the patella was shifted laterally at knee extension and migrated to the center of femoral groove with increased knee flexion. No significant deteriorations in chondral status were seen on second-look arthroscopy. CONCLUSION: The present study revealed that not all improved patellar trackings after MPFL reconstruction remained intact at follow-up. Chondral status in patellofemoral joint was not aggravated by MPFL reconstruction. LEVEL OF EVIDENCE: Therapeutic studies, Level IV.

Comparison of anterior knee laxity immediately after anatomic double-bundle anterior cruciate ligament reconstruction: Manual tensioning vs tensioning boot techniques.

Purpose: Tensioning technique at graft fixation is one of key factors for successful outcomes in ACL reconstruction. The tensioning boot, which had two tensioners and was fixed to the tibia with a bandage, was developed for precise graft tensioning. The purpose was to compare the anterior knee laxity between the manual tensioning and the tensioning boot techniques immediately after ACL reconstruction under anesthesia in order to elucidate the effectiveness of using the tensioning boot. Methods: 33 patients had anatomic double-bundle ACL reconstruction with semitendinosus tendon graft. After grafts were fixed with EndoButton-CL on lateral femoral cortex, grafts were tied to Double Spike Plate (DSP). Each graft was pre-tensioning with 20 N (totally 40 N) at 20 degree of flexion for 3 minutes using manually-held tensioner in 11 patients and using tensioner installed to tensioning boot in the remaining 22 patients before graft fixation, and were then fixed in the same manner. Tibial displacement under 67 and 89 N of tibial anterior load was measured by KT-2000 Knee Arthrometer under anesthesia before and immediately after operation. Results: The anterior knee laxity in the operated knee was 4.5 ± 1.0 mm in the manual tensioning group and 2.9 ± 0.9 mm in the tensioning boot group at 89 N of anterior load, showing a significant difference. (P < .0001) The side-to-side difference in the manual tensioning group was significantly less than that in the tensioning boot group. (P = .002). Conclusions: Anterior laxity of the operated knees as well as KT side-to-side difference immediately after ACL reconstruction was larger in the tensioning boot technique than the manual tensioning technique, when the graft was fixed in the same manner. Thus, the initial tension at graft fixation with the tensioning boot can be smaller than 40 N.

Outcome of double-bundle ACL reconstruction using hamstring tendons.

The objective of this article is to describe the clinical outcome of the transitional double-bundle procedure for anatomical ACL reconstruction. Subjects included 78 patients (average age 25 years) who had undergone ACL reconstruction with the transitional double-bundle procedure with multi-stranded hamstring tendons. The femoral socket for the anteromedial (AM) graft was created at 5-6 mm from the mid-sagittal line of the intercondylar notch at 2:00 or 10:00, and that for the posterolateral (PL) graft was drilled adjacent to the AM socket at 3:00 or 9:00. For the tibial side, two tunnels were made at the center of the footprint of the AM and PL bundles of the normal ACL. Patients were evaluated at 24 months or longer postoperatively based on the IKDC Knee Examination Form. Subjectively, 32 knees (41%) were graded as normal; 41 (53%), as nearly normal; 4 (5%), as abnormal; and 1 (1%) as graft rupture by re-injury. The average side-to-side difference in anterior laxity at manual maximum force with the KT-2000 arthrometer was 0.9 mm +/- 1.2. Seventy patients (93%) had a range between -1 mm and 2 mm. In conclusion the transitional double-bundle ACL reconstruction provided a satisfactory outcome after a short-term follow-up.

Rectangular tunnel double-bundle anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft to mimic natural fiber arrangement.

We describe our current technique of anatomic, double-bundle (DB), rectangular tunnel anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone (BPTB) graft. This technique mimics the natural, or anatomic, arrangement of the native ACL fibers. This technique has the following advantages: (1) creation of a DB ACL reconstruction with a single BPTB graft; (2) maximization of graft-tunnel contact area; (3) containment of the tunnel apertures within the anatomic ACL attachment footprint; (4) rotational control of the graft within the tunnels during and after fixation; and (5) preservation of notch anatomy.

Arthroscopic anterior cruciate ligament reconstruction using fresh-frozen bone plug-free allogeneic tendons: 10-year follow-up.

PURPOSE: To evaluate the long-term outcomes following arthroscopic-assisted anterior cruciate ligament (ACL) reconstruction using fresh-frozen allogeneic tendon. METHODS: Sixty-one athletically active patients (mean age at surgery, 20.9 years) who had arthroscopic-assisted ACL reconstruction using fresh-frozen free tendon allograft underwent physical examination, instrumented laxity measurement, radiographs, and thigh muscle strength at 10 to 14 years (mean, 11.5) postoperatively, and these data were compared with results of similar measurements obtained at 2 years postoperatively. RESULTS: Lachman test and pivot shift test were maintained as negative in 53 (87%) and 52 (85%) patients at follow-up, respectively. Quantitative measurements using the KT-2000 knee arthrometer showed 1.6 +/- 1.3 (mean +/- SD) mm in the side-to-side difference, and no more than 3 mm in 56 patients (92%) at final follow-up. All but one was assessed as normal or nearly normal by International Knee Documentation Committee score. Patient activity level was decreased at the long-term follow-up, but this change was mainly associated with changes in social context (e.g., graduation from school) rather than with knee limitations. None of the patients experienced deep infection or graft rejection. Degenerative joint disease on radiographs was seen in 13 out of 15 patients (87%) whose menisci had been excised, whereas it was observed in 12 out of 46 (26%) whose menisci had been preserved. CONCLUSIONS: A series of 61 patients with fresh-frozen bone plug-free tendon allografts using a 2-incision technique for arthroscopic ACL reconstruction results in long-term knee stabilization and functioning among young active individuals while simultaneously avoiding graft harvest site morbidity. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

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.

Correlation of 3D Shift and 3D Tilt of the Patella in Patients With Recurrent Dislocation of the Patella and Healthy Volunteers: An In Vivo Analysis Based on 3-Dimensional Computer Models.

BACKGROUND: The concepts of lateral deviation and lateral inclination of the patella, characterized as shift and tilt, have been applied in combination to evaluate patellar malalignment in patients with patellar dislocation. It is not reasonable, however, to describe the 3-dimensional (3D) positional relation between the patella and the femur according to measurements made on 2-dimensional (2D) images. PURPOSE: The current study sought to clarify the relation between lateral deviation and inclination of the patella in patients with recurrent dislocation of the patella (RDP) by redefining them via 3D computer models as 3D shift and 3D tilt. STUDY DESIGN: Descriptive laboratory study. METHODS: Altogether, 60 knees from 56 patients with RDP and 15 knees from 10 healthy volunteers were evaluated. 3D shift and tilt of the patella were analyzed with 3D computer models created by magnetic resonance imaging scans obtained at 10° intervals of knee flexion (0°-50°). 3D shift was defined as the spatial distance between the patellar reference point and the midsagittal plane of the femur; it is expressed as a percentage of the interepicondylar width. 3D tilt was defined as the spatial angle between the patellar reference plane and the transepicondylar axis. Correlations between the 2 parameters were assessed with the Pearson correlation coefficient. RESULTS: The patients' mean Pearson correlation coefficient was 0.895 ± 0.186 (range, -0.073 to 0.997; median, 0.965). In all, 56 knees (93%) had coefficients >0.7 (strong correlation); 1 knee (2%), >0.4 (moderate correlation); 2 knees (3%), >0.2 (weak correlation); and 1 knee (2%), <0.2 (no correlation). The mean correlation coefficient of the healthy volunteers was 0.645 ± 0.448 (range, -0.445 to 0.982; median, 0.834). A statistically significant difference was found in the distribution of the correlation coefficients between the patients and the healthy volunteers ( P = .0034). When distribution of the correlation coefficients obtained by the 3D analyses was compared with that by the 2D (conventional) analyses, based on the bisect offset index and patellar tilt angle, the 3D analyses showed statistically higher correlations between the lateral deviation and inclination of the patella ( P < .01). CONCLUSION: 3D shift and 3D tilt of the patella were moderately or strongly correlated in 95% of patients with RDP at 0° to 50° of knee flexion. CLINICAL RELEVANCE: It is not always necessary to use both parameters when evaluating patellar alignment, at least for knees with RDP at 0° to 50° of flexion. Such a description may enable surgeons to describe patellar alignment more simply, leading to a better, easier understanding of the characteristics of each patient with RDP.

3D Computed Tomography Evaluation of Morphological Changes in the Femoral Tunnel After Medial Patellofemoral Ligament Reconstruction With Hamstring Tendon Graft for Recurrent Patellar Dislocation.

BACKGROUND: Reconstruction of the medial patellofemoral ligament (MPFL) for recurrent lateral patellar dislocation is gaining popularity. However, the morphological changes in the femoral tunnel after MPFL reconstruction are still not fully documented. PURPOSE: This study used 3-dimensional (3D) computed tomography to evaluate morphological changes in the femoral tunnel after MPFL reconstruction with hamstring tendon graft to investigate factors affecting the phenomenon and to elucidate whether it is associated with clinical outcomes. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty-three patients with recurrent patellar dislocation were prospectively enrolled in this study. The patients included 6 males and 17 females with a mean age of 24 years (range, 14-53). The MPFL was reconstructed by creating 2 patellar bone sockets and 1 femoral bone socket anatomically under X-ray control, and the semitendinosus autograft was fixed with cortical suspension devices. Computed tomography scans obtained 3 weeks and 1 year after surgery were reconstructed into 3D constructs with a volume analyzer. Cross-sectional areas (CSAs) of the aperture and inside the femoral tunnel were compared between the 2 time points. Likewise, the location of tunnel walls and center of the femoral tunnel footprint were evaluated. Relationships were assessed between femoral tunnel morphological changes and potential risk factors-such as age, body mass index, sex, femoral tunnel positioning, patellar height, sulcus angle, congruence angle, lateral tilt angle, degree of trochlear dysplasia, lateral deviation of the tibial tubercle, and Kujala score. RESULTS: No patient reported recurrence of patellar dislocation during the follow-up period. The CSA of the femoral tunnel aperture enlarged by 41.1% ± 34.7% ( P < .01). The center, anterior border, and proximal border of the femoral tunnel significantly shifted in the anterior direction ( P < .01). The distal border significantly shifted in both anterior and distal directions ( P < .01). Patella alta was associated with distal migration of the tunnel center ( P < .05). Morphological changes were not associated with other risk factors or Kujala score. CONCLUSION: The CSA of the femoral tunnel aperture enlarged, and the tunnel aperture migrated anteriorly with time after MPFL reconstruction. Risk factors for patellar dislocation other than patella alta did not influence morphological changes of the femoral tunnel.

Healing of tibial bone tunnels after bone grafting for staged revision anterior cruciate ligament surgery: A prospective computed tomography analysis.

AIM: To quantify healing of tibial bone tunnels after bone grafting in two-stage ACL reconstruction revision. METHODS: Ten consecutive patients underwent autogenous bone grafting prior to ACL reconstruction revision (four females and six males, average age 28years). The indications for two-stage surgery were as follows: (1) the enlargement of the tibial tunnel aperture was >20mm in diameter or, (2) the existing tunnel was overlapped with the optimal tunnel and positioned more than a half tunnel diameter posterior to the optimal position. An autogenous iliac bone block was driven into a new tunnel. CT examinations were performed at three, 12 and 24weeks after bone grafting. Evaluations were performed on 15 axial planes at one-millimeter intervals from the articular surface perpendicular to the long axis of the tibia using the following three parameters: occupying ratio (OR), union ratio (UR), and bone mineral density (BMD) of grafted bone. RESULTS: The average ORs were 81, 85 and 94%, and the average URs were 49, 75 and 89% at three, 12 and 24weeks, respectively. Each parameter significantly increased over time. The average BMD was 510 and 571mg/cm(3) at 12 and 24weeks, respectively, with a significantly higher value at 24weeks. CONCLUSION: The average ORs, URs and BMD at 24weeks after bone grafting were higher than those at 12weeks, which suggests that at 24weeks after bone grating, the condition of the patients' beds becomes favorable for safe implantation and fixation of ACL graft revision. LEVEL OF EVIDENCE: Case series Level IV.

Change in the locus of dynamic loading axis on the knee joint after high tibial osteotomy.

The purpose of this study was to visualise the locus of the dynamic loading axis on the knee joint, and to evaluate changes in this locus during gait after high tibial osteotomy (HTO) in three patients who underwent HTO for medial compartment osteoarthritis (OA) of a varus knee. The bone structure of the lower limb and the relative position of skin markers were acquired from CT images. Motion capture data was acquired using spherical skin markers. Skeletal model movement during gait was calculated based on the movement of the markers. The locus of the dynamic loading axis on the knee joint was defined as the point on the proximal tibia joint surface that intersected with the loading axis of the lower limb, which passed through the centre of the femoral head and the centroid of multiple points surrounded by the distal tibia joint surface contour. This system was able to visualise the locus of the dynamic loading axis on the knee joint and not only lateral but also anterior-posterior direction movement. After HTO, the locus shifted from a medial and posterior area of the medial joint edge of the knee to a central area of the knee joint surface. This indicates that HTO shifted the dynamic loading axis. Lateral movement of the dynamic loading axis in the early stance phase of gait was reduced within a year after HTO.

Graft length changes in the bi-socket anterior cruciate ligament reconstruction: comparison between isometric and anatomic femoral tunnel placement.

PURPOSE: To compare the length change of grafts in bi-socket anterior cruciate ligament (ACL) reconstruction between isometric and anatomic placement. TYPE OF STUDY: Case series. METHODS: The subjects were 110 knees of 110 patients with a mean age of 27 years. All knees were reconstructed using multistranded autogenous semitendinosus tendon and the bi-socket procedure. Of those, 43 knees were reconstructed in the isometric position, around the isometric point (group I) and the remaining 67 in the anatomic position, mimicking the anatomic footprint of ACL (group II). Grouping was performed based on the femoral socket position. Each femoral socket for the anterior medial graft (AMG) and the posterolateral graft (PLG) for the left knee was positioned at 1 o'clock and 2 o'clock to 2:30 in group I, or 2 o'clock and 3 o'clock in group II in the posterior border of the notch. Their positioning for the right knee was at 11 o'clock and 9:30 to 10 o'clock in group I, or 10 o'clock and 9 o'clock in group II. The length changes of grafts were intraoperatively measured while extending the knee from 120 degrees to full extension, using a commercially available isometric positioner. The Student t test was used for statistical analysis. RESULTS: All the grafts showed the pattern of elongation approaching extension. The length change of AMG and PLG was 1.3+/-0.6 mm and 2.2+/-1.0 mm in the group I, 1.4+/-0.7 mm and 2.5+/-0.9 mm in the group II, respectively. There was no statistically significant difference in the values of AMG (P = .51) and PLG (P = .074) between the 2 groups. CONCLUSIONS: The length change of ACL grafts placed in the anatomic position was not significantly different from that positioned in the isometric position. LEVEL OF EVIDENCE: Level IV, case series.