Bart Muller

The concept of individualized anatomic anterior cruciate ligament (ACL) reconstruction

PurposeTo describe the concept of individualized anatomic anterior cruciate ligament (ACL) reconstruction.MethodsThe PubMed/Medline database was searched using keywords pertaining to ACL reconstruction. Relevant articles were reviewed in order to summarize important concepts of individualized surgery in ACL reconstruction. Surgical experiences with case examples are also highlighted.ResultsIndividualized ACL surgery allows for the customization of surgery to each individual patient. Accounting for graft selection and other characteristics such as anatomy, lifestyle and activity preferences may provide the patient with the best potential for a successful outcome. The surgeon should be comfortable with a variety of graft harvests and surgical techniques when practicing individualized surgery.ConclusionIndividualized anatomic ACL reconstruction is founded on the objective evaluation of functional anatomy and individual characteristics, thereby restoring the ACL as closely as possible to the native anatomy and function. The adoption and subsequent use of individualized surgery may facilitate improved clinical as well as objective outcomes, particularly in the long term.Level of evidenceV.

Indications and contraindications for double-bundle ACL reconstruction

Over recent years, double-bundle reconstruction has gained popularity after studies showed significant advantages of adding a second bundle with regard to outcomes and biomechanics; in particular, it resulted in less rotational instability than after reconstruction with a traditional single-bundle technique. As the focus shifted further towards the restoration of the native anatomy, both single-bundle and double-bundle ACL reconstruction were performed in an anatomical fashion and yielded similar results. To date, no consensus has developed as to whether double-bundle reconstruction is better than single-bundle reconstruction or vice versa. However, after surgeons started to individualise their surgical approach to the patient, it has been found that both the anatomical single- and double-bundle techniques have their own set of indications and contraindications. Reconstruction of the ligament should focus on restoration of the native functional and anatomical properties and should take the size, shape and orientation of the ACL into account. When indications and contraindications for the technique used are based on native anatomical characteristics, either a single-bundle or a double-bundle procedure can be performed according to the same double-bundle concept.

Development of computer tablet software for clinical quantification of lateral knee compartment translation during the pivot shift test

The pivot shift test is a commonly used clinical examination by orthopedic surgeons to evaluate knee function following injury. However, the test can only be graded subjectively by the examiner. Therefore, the purpose of this study is to develop software for a computer tablet to quantify anterior translation of the lateral knee compartment during the pivot shift test. Based on the simple image analysis method, software for a computer tablet was developed with the following primary design constraint – the software should be easy to use in a clinical setting and it should not slow down an outpatient visit. Translation of the lateral compartment of the intact knee was 2.0 ± 0.2 mm and for the anterior cruciate ligament-deficient knee was 8.9 ± 0.9 mm (p < 0.001). Intra-tester (ICC range = 0.913 to 0.999) and inter-tester (ICC = 0.949) reliability were excellent for the repeatability assessments. Overall, the average percent error of measuring simulated translation of the lateral knee compartment with the tablet parallel to the monitor increased from 2.8% at 50 cm distance to 7.7% at 200 cm. Deviation from the parallel position of the tablet did not have a significant effect until a tablet angle of 45°. Average percent error during anterior translation of the lateral knee compartment of 6mm was 2.2% compared to 6.2% for 2 mm of translation. The software provides reliable, objective, and quantitative data on translation of the lateral knee compartment during the pivot shift test and meets the design constraints posed by the clinical setting.

Predictors of Revision Surgery After Primary Anterior Cruciate Ligament Reconstruction

Background: Revision anterior cruciate ligament (ACL) reconstruction surgery occurs in 5% to 15% of individuals undergoing ACL reconstruction. Identifying predictors for revision ACL surgery is of essence in the pursuit of creating adequate prevention programs and to identify individuals at risk for reinjury and revision. Purpose: To determine predictors of revision ACL surgery after failed primary ACL reconstruction. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 251 participants (mean age ± SD, 26.1 ± 9.9 years) who had undergone primary ACL reconstruction 1 to 5 years earlier completed a comprehensive survey to determine predictors of revision ACL surgery at a mean 3.4 ± 1.3 years after the primary ACL reconstruction. Potential predictors that were assessed included subject characteristics (age at the time of surgery, time from injury to surgery, sex, body mass index, preinjury activity level, return to sport status), details of the initial injury (mechanism; concomitant injury to other ligaments, menisci, and cartilage), surgical details of the primary reconstruction (Lachman and pivot shift tests under anesthesia, graft type, femoral drilling technique, reconstruction technique), and postoperative course (length of rehabilitation, complications). Univariate and multivariate logistic regression analyses were performed to identify factors that predicted the need for revision ACL surgery. Results: Overall, 21 (8.4%) subjects underwent revision ACL surgery. Univariate analysis showed that younger age at the time of surgery (P = .003), participation in sports at a competitive level (P = .023), and double-bundle ACL reconstruction (P = .024) predicted increased risk of revision ACL surgery. Allograft reconstructions also demonstrated a trend toward greater risk of revision ACL surgery (P = .076). No other variables were significantly associated with revision ACL surgery. Multivariate analysis revealed that revision ACL surgery was only predicted by age at the time of surgery and graft type (autograft vs allograft). Conclusion: The overall revision ACL surgery rate after primary unilateral ACL reconstruction was 8.4%. Univariate predictors of revision ACL reconstruction included younger age at the time of surgery, competitive baseline activity level, and double-bundle ACL reconstruction. However, multivariable logistic regression analysis indicated that age and reconstruction performed with allograft were the only independent predictors of revision ACL reconstruction.

Progression of patellar tendinitis following treatment with platelet-rich plasma: case reports

PurposeThe use of platelet-rich plasma (PRP) is becoming more attractive given its favourable side effect profile and autologous nature, leading to rapid clinical adoption in the absence of high-level evidence. We are presenting three patients who developed a progression of patellar tendinitis following treatment, which to our knowledge is the first report of worsening of patellar tendinitis following PRP therapy.MethodsThe records of three patients with symptom exacerbation of patellar tendinitis following treatment with PRP were reviewed. IRB exemption was obtained. Clinical and operative records, radiographs, and MR imaging were reviewed for all patients.ResultsThree patients reported to our clinic for a second opinion with symptoms of anterior knee pain consistent with patellar tendinitis. Each patient had previously been treated with PRP therapy due to prolonged symptoms. Clinical and radiological findings following treatment included patellar tendon thickening, worsening pain, discontinuation of athletic participation in all three patients, and osteolysis of the distal pole of the patella in one patient identified during surgical intervention.ConclusionsGrowing interest in the use of autologous products for the management of chronic tendinopathies has led to widespread clinical implementation with minimal scientific support. It is tempting to apply a new treatment for management of a difficult clinical entity, especially when the risk/benefit ratio appears favourable. However, caution must be exercised as unexpected results may be encountered.Level of evidenceCase reports, Level V.

Individualized anatomic anterior cruciate ligament reconstruction.

Arthroscopic anterior cruciate ligament reconstruction (ACL-R) is a technique that continues to evolve. Good results have been established with respect to reducing anteroposterior laxity. However, these results have come into question because nonanatomic techniques have been ineffective at restoring knee kinematics and raised concerns that abnormal kinematics may impact long-term knee health. Anatomic ACL-R attempts to closely reproduce the patients individual anatomic characteristics. Measurements of the patients anatomy help determine graft choice and whether anatomic reconstruction should be performed with a single- or double-bundle technique. The bony landmarks and insertions of the anterior cruciate ligament (ACL) are preserved to assist with anatomic placement of both tibial and femoral tunnels. An anatomic single- or double-bundle reconstruction is performed with a goal of reproducing the characteristics of the native ACL. Long-term outcomes for anatomic ACL reconstruction are unknown. By individualizing ACL-R, we strive to reproduce the patients native anatomy and restore knee kinematics to improve patient outcomes.

Strategies for revision surgery after primary double-bundle anterior cruciate ligament (ACL) reconstruction

PurposeThe purpose of this article was to discuss pre- and intra-operative considerations as well as surgical strategies for different femoral and tibial tunnel scenarios in revision surgery following primary double-bundle anterior cruciate ligament (ACL) reconstruction.MethodsBased on the current literature of ACL revision surgery and surgical experience, an algorithm for revision surgery after primary double-bundle ACL reconstruction was created.ResultsA guideline and flowchart were created using a case-based approached for revision surgery after primary double-bundle ACL reconstruction.ConclusionRevision surgery after primary double-bundle ACL reconstruction can be a challenging procedure that requires flexibility and a repertoire of surgical techniques. The combination of pre-operative planning with 3D-CT reconstruction, in addition to careful intra-operative assessment, and the use of this flowchart can simplify the ACL revision procedure.Level of evidenceV.

ACL Graft Healing and Biologics

Operative reconstruction of a torn anterior cruciate ligament (ACL) has become the most broadly accepted treatment. An important, but underreported, outcome of ACL reconstruction is graft failure, which poses a challenge for the orthopedic surgeon. An understanding of the tendon-bone healing and the intra-articular ligamentization process is crucial for orthopedic surgeons to make appropriate graft choices and to be able to initiate optimal rehabilitation protocols after surgical ACL reconstruction. This article focuses on the current understanding of the tendon-to-bone healing process for both autografts and allografts and discusses strategies to biologically augment healing.

Defining Thresholds for the Patient Acceptable Symptom State for the IKDC Subjective Knee Form and KOOS for Patients Who Underwent ACL Reconstruction.

Background: A clinically meaningful change in patient-reported outcome (PRO) may not be associated with an acceptable state that corresponds to “feeling well,” also known as the patient acceptable symptom state (PASS). The PASS thresholds for the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) and the Knee injury and Osteoarthritis Outcome Score (KOOS) have not been determined for individuals after anterior cruciate ligament (ACL) reconstruction. Purpose: To determine the PASS thresholds for the IKDC-SKF and KOOS in individuals at 1 to 5 years after ACL reconstruction. Study Design: Cohort study (diagnosis): Level of evidence, 2. Methods: Individuals 1 to 5 years after primary ACL reconstruction completed a survey that included the IKDC-SKF and KOOS. All subjects assessed satisfaction with their current state by answering the question, “Taking into account all the activity you have during your daily life, your level of pain, and also your activity limitations and participation restrictions, do you consider the current state of your knee satisfactory?” Results: A total of 251 participants (mean age ± SD, 26.1 ± 9.9 years) completed the survey at an average of 3.4 ± 1.3 years after ACL reconstruction. Of these, 223 (89.2%) individuals indicated that they were in an acceptable symptom state (PASS-Y). Analysis of the receiver operating characteristic curve revealed that the IKDC-SKF and each of the KOOS subscales (pain, symptoms, activities of daily living [ADL], sport and recreation [sport/rec], and quality of life [QoL]) were significantly better identifiers of PASS than chance as indicated by the significance of the area under the curves. The PASS threshold (sensitivity, specificity) was 75.9 (0.83, 0.96) for the IKDC-SKF, 88.9 (0.82, 0.81) for the KOOS pain, 57.1 (0.78, 0.67) for the KOOS symptoms, 100.0 (0.70, 0.89) for the KOOS ADL, 75.0 (0.87, 0.88) for the KOOS sport/rec, and 62.5 (0.82, 0.85) for the KOOS QoL. In addition, the difference between PASS-Y and PASS-N was statistically significant (P < .001) for all PROs. Conclusion: To our knowledge, this is the first study to identify the PASS thresholds for the IKDC-SKF and the KOOS subscales for individuals 1 to 5 years after ACL reconstruction. By identifying threshold values for the PASS, this study provides additional information to facilitate interpretation of the IKDC-SKF and KOOS in daily practice and clinical research related to ACL reconstruction.

Appearance of the weight-bearing lateral radiograph in retrocalcaneal bursitis.

Background and purpose A retrocalcaneal bursitis is caused by repetitive impingement of the bursa between the Achilles tendon and the posterosuperior calcaneus. The bursa is situated in the posteroinferior corner of Kagers triangle (retrocalcaneal recess), which is a radiolucency with sharp borders on the lateral radiograph of the ankle. If there is inflammation, the fluid-filled bursa is less radiolucent, making it difficult to delineate the retrocalcaneal recess. We assessed whether the radiographic appearance of the retrocalcaneal recess on plain digital (filmless) radiographs could be used in the diagnosis of a retrocalcaneal bursitis. Methods Whether or not there was obliteration of the retrocalcaneal recess (yes/no) on 74 digital weight-bearing lateral radiographs of the ankle was independently assessed by 2 observers. The radiographs were from 24 patients (25 heels) with retrocalcaneal bursitis (confirmed on endoscopic calcaneoplasty); the control group consisted of 50 patients (59 heels). Results The sensitivity of the test was 83% for observer 1 and 79% for observer 2. Specificity was 100% and 98%, respectively. The kappa value of the interobserver reliability test was 0.86. For observer 1, intraobserver reliability was 0.96 and for observer 2 it was 0.92. Interpretation On digital weight-bearing lateral radiographs of a retrocalcaneal bursitis, the retrocalcaneal recess has a typical appearance.