There are isoheight points that measure constant femoral condyle heights along the knee flexion path.

PURPOSE: It is a challenge to evaluate the maintenance of medial and lateral soft tissue balance in total knee arthroplasty (TKA). This study aimed to determine the "isoheight" points and the "isoheight" axis (IHA) that can measure constant medial/lateral condyle heights during flexion of the knee, and compare the IHA with two major anatomical axes, the transepicondylar axis (TEA) and the geometric center axis (GCA). METHODS: Twenty-two healthy human knees were imaged using a combined MRI and dual fluoroscopic imaging system while performing a single-legged lunge (0°-120°). The isoheight points of the medial and lateral femoral condyles were defined as the locations with the least amount of changes in heights during the knee flexion; an IHA is the line connecting the medial and lateral isoheight points. The measured changes of the condyle heights using the IHA were compared with those measured using the TEA and GCA. RESULTS: Overall, the IHA was posterior and distal to the TEA, and anterior to the GCA. The isoheight points measured condyle height changes within 1.2 ± 2.3 mm at the medial and 0.7 ± 3.3 mm at the lateral sides during the knee flexion. Between 0° and 45°, the condyle height changes measured using the GCA (medial: 3.0 ± 1.8 mm, lateral: 2.3 ± 2.0 mm) were significantly larger than those of the IHA and the TEA (p < 0.05). Between 90° and 120°, the changes of the condyle heights measured using the TEA (medial: 5.3 ± 1.8 mm, lateral: 3.3 ± 1.8 mm) were significantly larger than those of the IHA and GCA (p < 0.05). CONCLUSION: There are isoheight points in the medial and lateral femoral condyles that can measure constant heights along the full range of knee flexion and could be used to formulate an "isoheight" axis (IHA) of the femur. The condyle height changes measured by the TEA and GCA were greater than the IHA measurements along the flexion path. These data could be used as a valuable reference to evaluate the condyle height changes after TKA surgeries and help achieve soft tissue balance and optimal knee kinematics along the flexion path. LEVEL OF EVIDENCE: IV.

In vivo kinematics and ligamentous function of the knee during weight-bearing flexion: an investigation on mid-range flexion of the knee.

PURPOSE: To investigate the in vivo femoral condyle motion and synergistic function of the ACL/PCL along the weight-bearing knee flexion. METHODS: Twenty-two healthy human knees were imaged using a combined MRI and dual fluoroscopic imaging technique during a single-legged lunge (0°-120°). The medial and lateral femoral condyle translation and rotation (measured using geometric center axis-GCA), and the length changes of the ACL/PCL were analyzed at: low (0°-30°), mid-range (30°-90°) and high (90°-120°) flexion of the knee. RESULTS: At low flexion (0°-30°), the strains of the ACL and the posterior-medial bundle of the PCL decreased. The medial condyle showed anterior translation and lateral condyle posterior translation, accompanied with a sharp increase in external GCA rotation (internal tibial rotation). As the knee continued flexion in mid-range (30°-90°), both ACL and PCL were slack (with negative strain values). The medial condyle moved anteriorly before 60° of flexion and then posteriorly, accompanied with a slow increase of GCA rotation. As the knee flexed in high flexion (90°-120°), only the PCL had increasingly strains. Both medial and lateral condyles moved posteriorly with a rather constant GCA rotation. CONCLUSIONS: The ACL and PCL were shown to play a reciprocal and synergistic role during knee flexion. Mid-range reciprocal anterior-posterior femoral translation or laxity corresponds to minimal constraints of the ACL and PCL, and may represent a natural motion character of normal knees. The data could be used as a valuable reference when managing the mid-range "instability" and enhancing high flexion capability of the knee after TKAs. LEVEL OF EVIDENCE: Level IV.

Myth busters: an AOA symposium: AOA critical issues.

One of the goals of the annual American Orthopaedic Association (AOA) meeting is to address controversy, both in leadership and clinical practice. A panel of experts in their respective fields presented the background and literature behind three "myths" in orthopaedic management and made conclusions as to their validity. First, Dr. Kocher took on the myth of prophylactic pinning on the contralateral "normal" side for a patient with a slipped capital femoral epiphysis. Second, Dr. Probe evaluated the myth that all intertrochanteric fractures are best treated with intramedullary devices. Last, Dr. Foster and Dr. Silvestri tackled the myth that autograft is always the best choice for anterior cruciate ligament (ACL) reconstruction. All three of these topics are subjects of current debate. The panel's careful examination of the available data along with their expertise in the management of these problems is presented in this thought-provoking JBJS Critical Issues article.

Does double-row rotator cuff repair improve functional outcome of patients compared with single-row technique? A systematic review.

BACKGROUND: The advantage of single-row versus double-row arthroscopic rotator cuff repair techniques has been a controversial issue in sports medicine and shoulder surgery. There is biomechanical evidence that double-row techniques are superior to single-row techniques; however, there is no clinical evidence that the double-row technique provides an improved functional outcome. HYPOTHESIS: When compared with single-row rotator cuff repair, double-row fixation, although biomechanically superior, has no clinical benefit with respect to retear rate or improved functional outcome. STUDY DESIGN: Systematic review. METHODS: The authors reviewed prospective studies of level I or II clinical evidence that compared the efficacy of single- and double-row rotator cuff repairs. Functional outcome scores included the American Shoulder and Elbow Surgeons (ASES) shoulder scale, the Constant shoulder score, and the University of California, Los Angeles (UCLA) shoulder rating scale. Radiographic failures and complications were also analyzed. A test of heterogeneity for patient demographics was also performed to determine if there were differences in the patient profiles across the included studies. RESULTS: Seven studies fulfilled our inclusion criteria. The test of heterogeneity across these studies showed no differences. The functional ASES, Constant, and UCLA outcome scores revealed no difference between single- and double-row rotator cuff repairs. The total retear rate, which included both complete and partial retears, was 43.1% for the single-row repair and 27.2% for the double-row repair (P = .057), representing a trend toward higher failures in the single-row group. CONCLUSION: Through a comprehensive literature search and meta-analysis of current arthroscopic rotator cuff repairs, we found that the single-row repairs did not differ from the double-row repairs in functional outcome scores. The double-row repairs revealed a trend toward a lower radiographic proven retear rate, although the data did not reach statistical significance. There may be a concerning trend toward higher retear rates in patients undergoing a single-row repair, but further studies are required.

Does the graft source really matter in the outcome of patients undergoing anterior cruciate ligament reconstruction? An evaluation of autograft versus allograft reconstruction results: a systematic review.

BACKGROUND: Despite the large number of anterior cruciate ligament reconstructions performed each year, there remains a significant controversy regarding the effect of the graft source on the functional outcome of patients. HYPOTHESIS: There is no difference in outcomes of autograft versus allograft anterior cruciate ligament reconstructions. STUDY DESIGN: Systematic review. METHODS: The authors systematically identified prospective studies (Oxford level of evidence I or II only) that included autograft patients, allograft patients, or both. Objective outcomes that were reported were meta-analyzed; this included pivot-shift results, KT-1000 arthrometer results, International Knee Documentation Committee (IKDC) scores, Lysholm Scores, graft failures, and postoperative complications. Two statistical analyses were performed. First a primary statistical analysis was performed comparing pooled autograft data (bone-patellar-tendon bone and hamstrings combined) and pooled allograft data (bone-patellar-tendon bone and hamstrings combined). To have a more comprehensive understanding of the differences between each specific graft source, a secondary analysis was performed without pooling the data; this directly compared the 4 types of graft sources that were studied. RESULTS: Over 400 scientific manuscripts were initially reviewed; 31 manuscripts fulfilled all of the search criteria. There were very few statistically significant differences between autograft and allograft tissue. The KT-1000 arthrometer laxity testing revealed a mean of 1.4 +/- 0.2 mm (weighted mean +/- standard error of the mean) for the allograft group compared with 1.8 +/- 0.1 mm for the autograft group (t = 2.40; P <.02). However, this difference was only for the mean score; there was no statistical significance when considering KT-1000 arthrometer measurements of greater than 3 or 5 mm. The percentage of patients receiving a final IKDC score of "A" (normal knee) was statistically significant for allograft tissue (43.9% +/- 5.5%) versus autograft tissue (28.2% +/- 1.0%) reconstructions. There was no statistically significant difference between the percentages of IKDC scores of A or B for patients receiving pooled allograft (82.9% +/- 4.2%) versus pooled autograft (87.2% +/- 0.9%) anterior cruciate ligament reconstruction (t = 1.01; P > .1). The graft failure rate was 4.7 +/- 0.5 per 100 for autograft reconstructions and 8.2 +/- 2.1 per 100 allograft reconstructions; although this may represent a trend, it is not statistically significant (t = 1.49; P > .1). The complication rate was slightly higher for autograft reconstructions at 3.5 +/- 0.4 complications per 100 autograft reconstructions compared with 2.4 +/- 1.1 complications per 100 allograft reconstructions, but not significant (t = 1.41; P > .1). CONCLUSION: After a comprehensive examination and statistical analysis of the modern literature, the authors could not identify an individual graft source that was clearly superior to the other graft sources. This led them to believe that, with currently available data, the graft source has a minimal effect on the outcome of patients undergoing anterior cruciate ligament reconstruction.

Platelet-rich plasma: from basic science to clinical applications.

Platelet-rich plasma (PRP) has been utilized in surgery for 2 decades; there has been a recent interest in the use of PRP for the treatment of sports-related injuries. PRP contains growth factors and bioactive proteins that influence the healing of tendon, ligament, muscle, and bone. This article examines the basic science of PRP, and it describes the current clinical applications in sports medicine. This study reviews and evaluates the human studies that have been published in the orthopaedic surgery and sports medicine literature. The use of PRP in amateur and professional sports is reviewed, and the regulation of PRP by antidoping agencies is discussed.

How effective is a saline arthrogram for wounds around the knee?

UNLABELLED: Traumatic arthrotomies may predispose patients to subsequent septic arthritis and therefore are regarded as serious injuries requiring emergent treatment. The saline arthrogram is a commonly used test to determine if a patient has a traumatic arthrotomy. We determined the sensitivity of the saline arthrogram to identify known intraarticular wounds in 78 patients (80 knees) undergoing elective arthroscopic procedures. There were 66 infrapatellar and 14 suprapatellar incisions. The average length of the incision was 7.5 mm. Intraarticular position was confirmed with a blunt probe. A saline arthrogram then was performed using 60 mL normal saline. The known arthrotomy (operative wound) was observed during the injection for evidence of saline leakage (positive static test). If no leakage was observed, the knee was brought through a range of motion with continued observation for leakage from the arthrotomy (positive dynamic test). Twenty-two of 80 knees had a positive test without passive range of motion of the knee (static sensitivity, 36%). Eight additional knees had a positive test with subsequent passive motion (dynamic sensitivity, 43%). Our data suggest a saline arthrogram has low sensitivity for detecting known small traumatic arthrotomy wounds of the knee. LEVEL OF EVIDENCE: Level I, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.