Beighton Score, Tibial Slope, Tibial Subluxation, Quadriceps Circumference Difference, and Family History Are Risk Factors for Anterior Cruciate Ligament Graft Failure: A Retrospective Comparison of Primary and Revision Anterior Cruciate Ligament Reconstructions.

PURPOSE: To assess patient history, physical examination findings, magnetic resonance imaging (MRI) and 3-dimensional computed tomographic (3D CT) measurements of those with anterior cruciate ligament (ACL) graft failure compared with primary ACL tear patients to better discern risk factors for ACL graft failure. METHODS: We performed a retrospective review comparing patients who underwent revision ACL reconstruction (ACLR) with a primary ACLR group with minimum 1-year follow-up. Preoperative history, examination, and imaging data were collected and compared. Measurements were made on MRI, plain radiographs, and 3D CT. Inclusion criteria were patients who underwent primary ACLR by a single surgeon at a single center with minimum 1-year follow-up or ACL graft failure with revision ACLR performed by the same surgeon. RESULTS: A total of 109 primary ACLR patients, mean age 33.7 years (range 15 to 71), enrolled between July 2016 and July 2018 and 90 revision ACLR patients, mean age 32.9 years (range 16 to 65), were included. The revision ACLR group had increased Beighton score (4 versus 0; P < .001) and greater side-to-side differences in quadricep circumference (2 versus 0 cm; P < .001) compared with the primary ACLR group. A family history of ACL tear was significantly more likely in the revision group (47.8% versus 16.5%; P < .001). The revision group exhibited significantly increased lateral posterior tibial slope (7.9° versus 6.2°), anterolateral tibial subluxation (7.1 versus 4.9 mm), and anteromedial tibia subluxation (2.7 versus 0.5 mm; all P < .005). In the revision group, femoral tunnel malposition occurred in 66.7% in the deep-shallow position and 33.3% in the high-low position. The rate of tibial tunnel malposition was 9.7% from medial to lateral and 54.2% from anterior to posterior. Fifty-six patients (77.8%) had tunnel malposition in ≥2 positions. Allograft tissue was used for the index ACLR in 28% in the revision group compared with 14.7% in the primary group. CONCLUSION: Beighton score, quadriceps circumference side-to-side difference, family history of ACL tear, lateral posterior tibial slope, anterolateral tibial subluxation, and anteromedial tibia subluxation were all significantly different between primary and revision ACLR groups. In addition, there was a high rate of tunnel malposition in the revision ACLR group.

Surgeon and Patient Upper Extremity Dominance Does Not Influence Clinical Outcomes After Total Shoulder Arthroplasty.

BACKGROUND: Surgeon- and patient-specific characteristics as they pertain to total shoulder arthroplasty (TSA) are limited in the literature. The influence of surgeon upper extremity dominance in TSA and whether outcomes vary among patients undergoing right or left TSA with respect to surgeon handedness have yet to be investigated. PURPOSE: To determine whether surgeon or patient upper extremity dominance has an effect on clinical outcomes after primary TSA at short-term follow-up. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective chart review was performed on prospectively collected data from an institutional shoulder registry. Patients who underwent primary TSA for glenohumeral osteoarthritis from June 2008 to August 2012 were included in the study. Preoperative and postoperative American Shoulder and Elbow Surgeons (ASES), Simple Shoulder Test (SST), and visual analog scale (VAS) pain scores were evaluated. To determine the clinical relevance of ASES scores, the minimal clinically important difference (MCID), the substantial clinical benefit (SCB), and the patient acceptable symptom state (PASS) were used. Active forward elevation, abduction, and external rotation were recorded for each patient. Glenoid version was also evaluated preoperatively on standard radiographs. RESULTS: Included in this study were 40 patients (n = 44 shoulders; mean age, 69.0 ± 7.3 years) with a mean follow-up of 36.5 ± 16.2 months. Final active range of motion between patients who underwent dominant versus nondominant and left versus right TSA by a right-handed surgeon was not significantly different. Clinical outcomes including the ASES, SST, and VAS pain scores were compared, and no statistical significance was identified between groups. With regard to the ASES score, 89% of patients achieved the MCID, 64% achieved the SCB, and 60% reached or exceeded the PASS. No significant difference in preoperative glenoid version between groups could be found. CONCLUSION: With the numbers available, neither patient nor surgeon upper extremity dominance had a significant influence on clinical outcomes after primary TSA at short-term follow-up. CLINICAL RELEVANCE: The influence of surgeon and patient upper extremity dominance on TSA outcomes is an important consideration, given the preferential use of the dominant extremity exhibited by most patients during activities of daily living. To this, operating on a right shoulder might be technically more demanding for a right-handed surgeon and vice versa, as it is considered in other subspecialties.

Low-Profile Dual Small Plate Fixation Is Biomechanically Similar to Larger Superior or Anteroinferior Single Plate Fixation of Midshaft Clavicle Fractures.

BACKGROUND: Limited biomechanical data exist for dual small plate fixation of midshaft clavicle fractures, and no prior study has concurrently compared dual small plating to larger superior or anteroinferior single plate and screw constructs. PURPOSE: To biomechanically compare dual small orthogonal plating, superior plating, and anteroinferior plating of midshaft clavicle fractures by use of a cadaveric model. STUDY DESIGN: Descriptive laboratory study. METHODS: The study used 18 cadaveric clavicle specimens (9 pairs total), and 3 plating techniques were studied: anteroinferior, superior, and dual. The dual plating technique used smaller diameter plates and screws (1.6-mm thickness) than the other, single plate techniques (3.3-mm thickness). Each of the 9 clavicle pairs was randomly assigned a combination of 2 plating techniques, and randomization was used to determine which techniques were used for the right and left specimens. Clavicles were plated and then osteotomized to create an inferior butterfly fracture model, which was then fixed with a single interfragmentary screw. Clavicle specimens were then potted for mechanical testing. Initial bending, axial, and torsional stiffness of each construct was determined through use of a randomized nondestructive cyclic testing protocol followed by load to failure. RESULTS: No significant differences were found in cyclical axial (P = .667) or torsional (P = .526) stiffness between plating groups. Anteroinferior plating demonstrated significantly higher cyclical bending stiffness than superior plating (P = .005). No significant difference was found in bending stiffness between dual plating and either anteroinferior (P = .129) or superior plating (P = .067). No significant difference was noted in load to failure among plating methods (P = .353). CONCLUSION: Dual plating with a smaller plate-screw construct is biomechanically similar to superior and anteroinferior single plate fixation that uses larger plate-screw constructs. No significant differences were found between dual plating and either superior or anteroinferior single plating in axial, bending, or torsional stiffness or in bending load to failure. Dual small plating is a viable option for fixing midshaft clavicle fractures and may be a useful low-profile technique that avoids a larger and more prominent plate-screw construct. CLINICAL RELEVANCE: Plate prominence and hardware irritation are commonly reported complaints and reasons for revision surgery after plate fixation of midshaft clavicle fractures. Dual small plate fixation has been used to improve cosmetic acceptability, minimize hardware irritation, and decrease reoperation rate. Biomechanically, dual small plate fixation performed similarly to larger single plate fixation in this cadaveric model of butterfly fracture.

Characterization of Growth Factors, Cytokines, and Chemokines in Bone Marrow Concentrate and Platelet-Rich Plasma: A Prospective Analysis.

BACKGROUND: Platelet-rich plasma (PRP) and bone marrow concentrate (BMC) are orthobiologic therapies with numerous growth factors and other bioactive molecules. Before the clinical utility of PRP and BMC is optimized as a combined therapy or monotherapy, an improved understanding of the components and respective concentrations is necessary. PURPOSE: To prospectively measure and compare anabolic, anti-inflammatory, and proinflammatory growth factors, cytokines, and chemokines in bone marrow aspirate (BMA), BMC, whole blood, leukocyte-poor PRP (LP-PRP), and leukocyte-rich PRP (LR-PRP) from samples collected and processed concurrently on the same day from patients presenting for elective knee surgery. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Patients presenting for elective knee surgery were prospectively enrolled over a 3-week period. Whole blood from peripheral venous draw and BMA from the posterior iliac crest were immediately processed via centrifugation and manual extraction methods to prepare LR-PRP, LP-PRP, and BMC samples, respectively. BMA, BMC, whole blood, LR-PRP, and LP-PRP samples were immediately assayed and analyzed to measure protein concentrations. RESULTS: BMC had a significantly higher interleukin 1 receptor antagonist (IL-1Ra) concentration than all other preparations (all P < .0009). LR-PRP also had a significantly higher IL-1Ra concentration than LP-PRP (P = .0006). There were no significant differences in IL-1Ra concentration based on age, sex, body mass index, or chronicity of injury in all preparations. LR-PRP had significantly higher concentrations of platelet-derived growth factor AA (PDGF-AA) and PDGF-AB/BB than all other preparations (all P < .0006). LR-PRP also had significantly higher concentrations of matrix metalloproteinase 1 (MMP-1) and soluble CD40 ligand than all other preparations (all P < .004). LP-PRP had significantly higher concentrations of MMPs, namely MMP-2, MMP-3, and MMP-12, than all other preparations (all P < .007). CONCLUSION: BMC is a clinically relevant source of anti-inflammatory biologic therapy that may be more effective in treating osteoarthritis and for use as an intra-articular biologic source for augmented healing in the postsurgical inflammatory and healing phases, owing to its significantly higher concentration of IL-1Ra as compared with LR-PRP and LP-PRP. Additionally, LR-PRP had a significantly higher concentration of IL-1Ra than LP-PRP. In cases where increased vascularity and healing are desired for pathological or injured tissues, including muscle and tendon, LR-PRP may be optimal given its higher overall concentrations of PDGF, TGF-ß, EGF, VEGF, and soluble CD40 ligand.

Primary Acromioclavicular-Coracoclavicular Reconstruction Using 2 Allografts, TightRope, and Stabilization to the Acromion.

Acromioclavicular (AC) joint injuries are a common cause of shoulder pain, particularly among young athletes participating in contact sports. Injuries to the AC joint most commonly occur from direct impact at the acromion and are classified as types I to VI. Although most AC joint injuries can be treated nonoperatively, types IV to VI are best treated with surgery, with type III being controversial and most surgeons recommending an initial trial of nonoperative treatment. Although numerous surgical techniques have been described, no gold standard technique has been established. Biomechanical testing suggests that anatomic reconstruction of both the AC and coracoclavicular ligaments results in a superior surgical construct. The objective of this Technical Note is to describe our preferred technique for the primary treatment of AC joint instability in the acute and chronic setting. Using 2 free tendon grafts in combination with a cortical button suspensory device combines the advantages of a nonrigid biologic and anatomic AC and coracoclavicular ligament reconstruction while benefiting from the strength of a cortical suspensory device in resisting displacement of the AC joint.

Mini-open Repair of the Floating Anterior Inferior Glenohumeral Ligament: Combined Treatment of Bankart and Humeral Avulsion of the Glenohumeral Ligament Lesions.

Anterior shoulder instability often results from avulsion of the anterior inferior glenohumeral ligament (aIGHL) off its insertion on the glenoid, yielding a Bankart lesion. Although less common, avulsion of the ligament attachment to the humerus results in a humeral avulsion of the glenohumeral ligament (HAGL) lesion. Combined Bankart and HAGL lesions, also termed the "floating aIGHL," create a complex pathology that is not detailed significantly in the literature. We believe a mini-open approach is a viable and reproducible procedure for treatment because it allows for protection of the axillary nerve and other neurovascular structures while providing optimal exposure to both the humeral insertion site of the distal aIGHL and the Bankart lesion, ensuring anatomic restoration. The purpose of this Technical Note is to describe our preferred technique to surgically treat the floating aIGHL, consisting of an anterior HAGL and concomitant Bankart lesion repair through a mini-open approach.

Surgical Repair of Dynamic Snapping Biceps Femoris Tendon.

A snapping biceps tendon is an infrequently seen and commonly misdiagnosed pathology, leaving patients with persistent symptoms that can be debilitating. Patients will present with a visible, audible, and/or painful snap over the lateral aspect of their knee when performing squats, sitting in low seats, or participating in activities with deep knee flexion. A thorough knowledge of the anatomy is essential for surgical treatment of this pathology, which is caused by a detachment of the direct arms of the long and short heads of the biceps femoris off the fibular styloid. This Technical Note provides a diagnostic approach, postoperative management, and details of a surgical technique to treat a snapping biceps tendon with an anatomic repair of the long and short head attachments of the biceps femoris to the posterolateral fibular styloid.

Radiographic Reference Points Are Inaccurate With and Without a True Lateral Radiograph: The Importance of Anatomy in Medial Patellofemoral Ligament Reconstruction.

BACKGROUND: Studies have reported methods for radiographically delineating medial patellofemoral ligament (MPFL) femoral tunnel position on a true lateral knee radiograph. However, obtaining a true lateral fluoroscopic radiograph intraoperatively can be challenging, rendering radiographic methods for tunnel positioning potentially inaccurate. PURPOSE: To quantify the magnitude of MPFL femoral tunnel malposition that occurs on true lateral and aberrant lateral knee radiographs when using a previously reported radiographic technique for MPFL femoral tunnel localization. STUDY DESIGN: Descriptive laboratory study. METHODS: Ten fresh-frozen cadaveric knees were dissected to expose the MPFL femoral insertion and surrounding medial knee anatomy. True lateral and aberrant lateral knee radiographs at 2.5°, 5°, and 10° off-axis were obtained with a standard mini C-arm in 4 orientations: anterior to posterior, posterior to anterior, caudal, and cephalad. A previously reported radiographic method for MPFL femoral localization was performed on all radiographs and compared in reference to the anatomic MPFL attachment center. RESULTS: The radiographic point, as previously described, was a mean distance of 4.1 mm from the anatomic MPFL attachment on a true lateral knee radiograph. The distance between the anatomic MPFL attachment center and the radiographic point significantly increased on aberrant lateral knee radiographs with as little as 5° of rotational error in 3 of 4 orientations of rotation when a standard mini C-arm was used. This corresponded to a malposition of 7.5, 9.2, and 8.1 mm on 5°-aberrant radiographs in the anterior-posterior, posterior-anterior, and cephalad orientations, respectively (P < .005). In the same 3 orientations of rotation, MPFL tunnel malposition on the femur exceeded 5 mm on 2.5° aberrant radiographs. CONCLUSION: The commonly utilized radiographic point, as previously described for MPFL femoral tunnel placement, results in inaccurate tunnel localization on a true lateral radiograph, and this inaccuracy is perpetuated with aberrant radiography. Aberrant lateral knee imaging of as little as 5° off-axis from true lateral has a significant effect on placement of a commonly used radiographic point relative to the anatomic MPFL femoral attachment center and results in nonanatomic MPFL tunnel placement. CLINICAL RELEVANCE: This study demonstrates that radiographic localization of the MPFL femoral tunnel results in inaccurate tunnel placement on a true lateral radiograph, particularly when there is deviation from a true lateral fluoroscopic image, which can be difficult to obtain intraoperatively. Assessing anatomy directly intraoperatively, rather than relying solely on radiographs, may help avoid MPFL tunnel malposition.

Current concepts in the treatment of acromioclavicular joint dislocations.

PURPOSE: To conduct a systematic review of the literature in relation to 3 considerations in determining treatment options for patients with acromioclavicular (AC) joint dislocations: (1) operative versus nonoperative management, (2) early versus delayed surgical intervention, and (3) anatomic versus nonanatomic techniques. METHODS: The PubMed database was searched in October 2011 using the single term acromioclavicular and the following search limits: any date, humans, English, and all adult (19+). Studies were included if they compared operative with nonoperative treatment, early with delayed surgical intervention, or anatomic with nonanatomic surgical techniques. Exclusion criteria consisted of the following: Level V evidence, laboratory studies, radiographic studies, biomechanical studies, fractures or revisions, meta-analyses, and studies reporting preliminary results. RESULTS: This query resulted in 821 citations. Of these, 617 were excluded based on the title of the study. The abstracts and articles were reviewed, which resulted in the final group of 20 studies that consisted of 14 comparing operative with nonoperative treatment, 4 comparing early with delayed surgical intervention, and 2 comparing anatomic with nonanatomic surgical techniques. The lack of higher level evidence prompted review of previously excluded studies in an effort to explore patterns of publication related to operative treatment of the AC joint. This review identified 120 studies describing 162 techniques for operative reconstruction of the AC joint. CONCLUSIONS: There is a lack of evidence to support treatment options for patients with AC joint dislocations. Although there is a general consensus for nonoperative treatment of Rockwood type I and II lesions, initial nonsurgical treatment of type III lesions, and operative intervention for Rockwood type IV to VI lesions, further research is needed to determine if differences exist regarding early versus delayed surgical intervention and anatomic versus nonanatomic surgical techniques in the treatment of patients with AC joint dislocations. LEVEL OF EVIDENCE: Level III, systematic review of Level II and Level III studies and one case series.

Arthroscopically pertinent anatomy of the anterolateral and posteromedial bundles of the posterior cruciate ligament.

BACKGROUND: The clock-face method to identify the femoral posterior cruciate ligament (PCL) attachment has poor accuracy and reproducibility. Measurements of clinically relevant anatomic structures would provide more useful surgical guidance. The purpose of the present study was to describe the attachments of the anterolateral and posteromedial bundles of the PCL relative to relevant landmarks to assist with arthroscopic anatomic PCL reconstructions. METHODS: Dissections were performed on twenty nonpaired fresh-frozen cadaveric knees. RESULTS: The distal articular cartilage margin of the intercondylar notch had a consistent shape conforming to the attachments of the anterolateral and posteromedial bundles. The mean distance (and standard deviation) between the femoral centers of the anterolateral and posteromedial bundles was 12.1 ± 1.3 mm. The distal margins of the anterolateral and posteromedial bundles were a mean of 1.5 ± 0.8 mm and 5.8 ± 1.7 mm proximal to the notch articular cartilage, respectively. On the tibia, the lateral plateau articular cartilage, the medial meniscus attachment, and an osseous ridge ("bundle ridge") separating the anterolateral and posteromedial bundles were important arthroscopic landmarks. The mean distance between the tibial centers of the anterolateral and posteromedial bundles was 8.9 ± 1.2 mm. CONCLUSIONS: The pertinent landmarks identified during arthroscopic PCL reconstruction consistently marked the borders of the attachments of the anterolateral and posteromedial bundles. To guide femoral tunnel placement, the centers of both bundles should be triangulated relative to the reported landmarks. Furthermore, the distal edge of the femoral anterolateral bundle should be placed adjacent to the articular cartilage, whereas the posteromedial bundle should be centered, on average, 8.6 mm proximal to the cartilage margin, just distal to the medial intercondylar ridge. On the tibia, the PCL tunnel should be placed just anterosuperior to the bundle ridge, with use of the lateral articular cartilage and medial meniscus attachment to guide placement. CLINICAL RELEVANCE: The results of the present study can assist with more anatomic tunnel placement during single and double-bundle PCL reconstructions. The results also suggest that two reconstruction tunnels are needed to reconstruct the broad femoral attachment, whereas one reconstruction tunnel should be investigated further for the compact tibial attachment.

Radiographic landmarks for tunnel positioning in double-bundle ACL reconstructions.

PURPOSE: The purpose of this study was to establish quantitative and qualitative radiographic landmarks for identifying the femoral and tibial attachment sites of the AM and PL bundles of the native ACL and to assess the reproducibility of identification of these landmarks using intraclass correlation coefficients. It was hypothesized that the radiographic positions of the AM and PL bundles could be defined in relation to anatomic landmarks and radiographic reference lines. METHODS: The femoral and tibial attachment sites of the AM and PL bundles on twelve cadaveric knees were labeled with radio-opaque markers. The positions of the AM and PL bundle attachment sites were quantified on radiographs by three independent examiners. RESULTS: On the lateral femoral view, the AM bundle was located at 21.6 ± 5.6% of the sagittal diameter of the femur drawn along Blumensaat's line and 14.2 ± 7.7% distal to the notch roof along the maximum notch height. The PL bundle was located at 28.9 ± 4.6% of the sagittal diameter and 42.3 ± 6.0% of the notch height. The knee flexion angle at which the AM and PL bundle attachment sites were horizontally oriented was 115 ± 7.1°. On the tibial AP view, the AM and PL bundles were located at 44.2 ± 3.4 and 50.1 ± 2.1%, respectively, from the medial aspect of the tibia along its coronal diameter. On the lateral view, the distances from the AM and PL bundles to the anterior tibial margin measured along the tibial sagittal diameter were 36.3 ± 3.8 and 51.0 ± 4.0%, respectively. The center of the PL bundle attachment was located almost precisely at the center of the tibial plateau in both the coronal and sagittal planes. CONCLUSIONS: This study defines the radiographic locations of the femoral and tibial bundle attachment sites of the native ACL and a reliable and transferrable protocol for identifying these sites on radiographs in relation to surrounding landmarks and digitally projected reference lines. In addition, it was found that the femoral attachments of the AM and PL bundles were horizontally aligned at 115° of knee flexion and the PL bundle tibial attachment was located essentially at the center of the tibia.

Arthroscopically pertinent landmarks for tunnel positioning in single-bundle and double-bundle anterior cruciate ligament reconstructions.

BACKGROUND: Quantification of the overall anterior cruciate ligament (ACL) and anteromedial (AM) and posterolateral (PL) bundle centers in respect to arthroscopically pertinent bony and soft tissue landmarks has not been thoroughly assessed. HYPOTHESIS: A standardized anatomical measurement method can quantitate the locations of the ACL and AM and PL bundle centers in reference to each other and anatomical landmarks. STUDY DESIGN: Descriptive laboratory study. METHODS: Quantification of the ACL and its bundle attachments was performed on 11 cadaveric knees using a radio frequency-tracking device. RESULTS: The tibial ACL attachment center was 7.5 mm medial to the anterior horn of the lateral meniscus, 13.0 mm anterior to the retro-eminence ridge, and 10.5 mm posterior to the ACL ridge. The femoral ACL attachment center was 1.7 mm proximal to the bifurcate ridge and 6.1 mm posterior to the lateral intercondylar ridge. The tibial AM attachment center was 8.3 mm medial to the anteromedial aspect of the lateral meniscus anterior horn, 17.8 mm anterior to the retro-eminence ridge, and 5.6 mm posterior to the ACL ridge. The femoral AM attachment center was 4.8 mm proximal to the bifurcate ridge and 7.1 mm posterior to the lateral intercondylar ridge. The tibial PL bundle attachment center was 6.6 mm medial to the posteromedial aspect of the lateral meniscus anterior horn, 10.8 mm anteromedial to the root attachment of the lateral meniscus posterior horn, and 8.4 mm anterior to the retro-eminence ridge. The femoral PL bundle attachment center was 5.2 mm distal to the bifurcate ridge and 3.6 mm posterior to the lateral intercondylar ridge. CONCLUSION: The authors developed a comprehensive compilation of measurements of arthroscopically pertinent bony and soft tissue landmarks that quantitate the ACL and its individual bundle attachment centers on the tibia and femur. CLINICAL RELEVANCE: These clinically relevant arthroscopic landmarks may enhance single- and double-bundle ACL reconstructions through improved tunnel placement.

Kinematic impact of anteromedial and posterolateral bundle graft fixation angles on double-bundle anterior cruciate ligament reconstructions.

BACKGROUND: Currently in double-bundle anterior cruciate ligament (ACL) reconstructions, the range of knee flexion angles that surgeons use for anteromedial (AM) and posterolateral (PL) bundle graft fixation spans from 0 degrees to 90 degrees for both bundle grafts. Despite the recent popularity of this procedure, no consensus exists on an optimal set of AM and PL graft fixation angles. HYPOTHESIS: Graft fixation angles that simulate the native tensioning relationship of the AM and PL bundles will produce kinematic results similar to the intact knee, while graft fixation angles that do not simulate this relationship will under- or overconstrain the knee. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve cadaveric knees were biomechanically tested in the intact state, ACL-sectioned state, and a randomized order of 7 double-bundle ACL reconstructed states at multiple graft fixation angle combinations. For each test state, data were collected for 88 N anterior tibial loads, 10 N.m valgus torques, 5 N.m internal rotation torques, and 2 simulated pivot shift loads consisting of a 5 N.m internal rotation torque coupled with either a 10 N.m valgus torque or an 88 N anterior tibial load at 0 degrees, 20 degrees, 30 degrees, 60 degrees, and 90 degrees of knee flexion. RESULTS: The AM and PL graft fixation angle combinations of 0 degrees /0 degrees (AM graft fixation angle/PL graft fixation angle), 60 degrees /0 degrees, 45 degrees /15 degrees, and 75 degrees /15 degrees restored normal laxity to the reconstructed knee in all of the biomechanical tests. The 30 degrees /30 degrees, 60 degrees /60 degrees, and 90 degrees /90 degrees graft fixation angle combinations significantly restricted knee laxity compared with the intact state in various biomechanical tests. CONCLUSION: We found that as long as the PL bundle graft was fixed between 0 degrees and 15 degrees , the AM graft could be fixed up to 75 degrees without restricting knee laxity. However, fixation of the PL graft at 30 degrees of knee flexion and above significantly overconstrained the knee. CLINICAL RELEVANCE: This study provides a range of angles that can be used in double-bundle ACL reconstructions to restore normal knee stability without causing overconstraint.

Patellar height and tibial slope after opening-wedge proximal tibial osteotomy: a prospective study.

BACKGROUND: Further knee surgery after proximal tibial osteotomies has been reported to have a more difficult surgical exposure due to decreased patellar height after the osteotomy. Although a decrease in patellar height has been reported for closing-wedge proximal tibial osteotomies, it has not been widely verified among opening-wedge procedures. HYPOTHESIS: A significant decrease in patellar height would result after opening-wedge proximal tibial osteotomies and a postoperative change in tibial slope would also result, depending on the medial tibial plate position, which would affect patellar height. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients (n = 129) who underwent opening-wedge proximal tibial osteotomies (n = 130) were prospectively followed. Patellar height was calculated for preoperative lateral knee radiographs, and postoperatively at 2 weeks and 3 and 6 months. The Insall-Salvati, Blackburne-Peel, and Caton-Deschamps indices and a modified Miura and Kawamura index were used to calculate patellar height. Posterior tibial slope was also calculated for preoperative and 6-month postoperative knees. RESULTS: Coronal plane alignment changed significantly, from 24.6% to 55.2% of the tibial weightbearing axis. The overall decrease in patellar height for all patients was significant from preoperative assessment to the 2-week postoperative assessment and to both 3-month and 6-month follow-up with all 4 methods. The Insall-Salvati index decreased from 1.03 preoperatively to 0.99 at 2 weeks postoperatively, 0.97 at 3 months, and 0.95 at 6 months postoperatively. The Blackburne-Peel index decreased from 0.90 preoperatively to 0.75, 0.77, and 0.76, respectively, at each postoperative interval. The Caton-Deschamps index decreased from 0.98 preoperatively to 0.87, 0.86, and 0.84 at each postoperative measurement. The Miura-Kawamura index changed from 0.76 preoperatively to 0.61, 0.63, and 0.60 for each postoperative assessment. The average tibial slope significantly increased from 9.0 degrees to 11.9 degrees overall for all patients. In comparing the plate position, the tibial slope significantly increased from 8.8 degrees preoperatively to 13.1 degrees at 6 months postoperatively for anteromedially positioned plates and from 9.3 degrees to 10.3 degrees for posteromedially positioned plates. CONCLUSION: Opening-wedge proximal tibial osteotomies decrease patellar height within the first 3 postoperative months. Shortening of the patellar tendon may affect future surgeries and needs to be evaluated in preoperative assessment. Moreover, a significant increase in tibial slope occurred, which may affect patellar height and future ligament reconstructions.

Radiographic identification of the primary posterolateral knee structures.

BACKGROUND: It is often difficult to identify the attachment sites of the fibular collateral ligament, popliteus tendon, and popliteofibular ligament for chronic posterolateral knee injuries or during revision surgeries. Descriptions of radiographic landmarks for these attachment sites would assist in the intraoperative identification of their locations and also allow for postoperative assessment of the placement of reconstruction tunnels. HYPOTHESIS: Identification of qualitative and quantitative radiographic landmarks for the attachments of the main posterolateral knee structures are reproducible among observers of various experience levels and allow for improved intraoperative and postoperative identification of these attachment sites. STUDY DESIGN: Descriptive laboratory study. METHODS: Dissections were performed on 11 cadaveric knee specimens. The attachments and locations of the investigated structures were labeled with radiopaque markers. The positions of the attachments relative to other attachment sites, labeled bony landmarks, and superimposed reference lines were quantified on anteroposterior and lateral radiographs. Measurements were performed by 3 independent examiners. Intraobserver and interobserver reliability was determined using intraclass correlation coefficients. RESULTS: Overall intraclass correlation coefficients for intraobserver reproducibility and interobserver reliability were calculated to be 0.981 and 0.983, respectively. On the anteroposterior view, the perpendicular distances from a line intersecting the femoral condyles to the popliteus tendon, proximal fibular collateral ligament, and lateral gastrocnemius tendon were 14.5, 27.1, and 34.5 mm, respectively. On the lateral view, the femoral attachments of the fibular collateral ligament, popliteus tendon, and lateral gastrocnemius tendon were 4.3, 12.2, and 13.1 mm, respectively, from the lateral epicondyle. In addition, the fibular collateral ligament and popliteus tendon were located within 1 mm of a reference line projected along the posterior femoral cortex distally, and also were located within the posteroinferior quadrant bound by the posterior femoral cortex extension reference line and another reference line perpendicular to it at the posterior margin of Blumensaat's line. CONCLUSION: Comprehensive qualitative and quantitative guidelines for assessing posterolateral knee structures on both anteroposterior and lateral knee radiographs were described. CLINICAL SIGNIFICANCE: This radiographic information regarding the attachment sites of posterolateral structures can serve as a valuable reference for preoperative, intraoperative, and postoperative assessments of surgical reconstructions.