Faculty Bibliography

BACKGROUND:Preoperative emotional distress has been shown to negatively influence joint arthroplasty and spine surgery, but limited data exist for foot and ankle outcomes. Emotional distress can be captured through modern tools like the Patient-Reported Outcomes Instrument Measurement System (PROMIS) anxiety domain. We hypothesized that patients with greater preoperative PROMIS anxiety scores would report greater pain and less function after foot and ankle surgery than patients with lower preoperative anxiety levels. METHODS:Elective foot and ankle surgeries from May 2016 to December 2017 were retrospectively identified. PROMIS anxiety, pain interference (PI), and physical function (PF) scores were collected before and after surgery. Patients were grouped based on preoperative PROMIS scores greater or less than 59.4. A cutoff of PROMIS anxiety above 59.4 was selected as the threshold that corresponds to traditional measures of anxiety. RESULTS:< .001; respectively). CONCLUSION/CONCLUSIONS:Our evidence showed that preoperative emotional anxiety predicted worse pain and function at early operative follow-up. Measures of preoperative anxiety could be useful in identifying patients at risk for poorer operative outcomes, but continued study is necessary. LEVEL OF EVIDENCE/METHODS:Level III, retrospective comparative study.

BACKGROUND:Symptomatic articular cartilage lesions of the knee are common and are being treated surgically with increasing frequency. While many studies have reported outcomes following a variety of cartilage restoration procedures, few have investigated outcomes of revision surgery after a failed attempt at cartilage repair or reconstruction. PURPOSE/OBJECTIVE:To investigate outcomes of revision cartilage restoration procedures for symptomatic articular cartilage lesions of the knee following a previously failed cartilage reconstructive procedure. STUDY DESIGN/METHODS:Systematic review; Level of evidence, 4. METHODS:A literature search was performed by use of the PubMed, EMBASE, and MEDLINE/Ovid databases for relevant articles published between 1975 and 2017 that evaluated patients undergoing revision cartilage restoration procedure(s) and reported outcomes using validated outcome measures. For studies meeting inclusion criteria, relevant information was extracted. RESULTS:Ten studies met the inclusion criteria. Lesions most commonly occurred in the medial femoral condyle (MFC) (52.8%), with marrow stimulation techniques (MST) the index procedure most frequently performed (70.7%). Three studies demonstrated inferior outcomes of autologous chondrocyte implantation (ACI) following a previous failed cartilage procedure compared with primary ACI. One study comparing osteochondral allograft (OCA) transplant following failed microfracture (MFX) with primary OCA transplant demonstrated similar clinical outcomes and graft survival at midterm follow-up. No studies reported outcomes following osteochondral autograft transfer (OAT) or newer techniques. CONCLUSION/CONCLUSIONS:This systematic review of the literature reporting outcomes following revision articular cartilage restoration procedures (most commonly involving the MFC) demonstrated a high proportion of patients who underwent prior MST. Evidence is sufficient to suggest that caution should be taken in performing ACI in the setting of prior MST, likely secondary to subchondral bone compromise. OCA appears to be a good revision treatment option even if the subchondral bone has been violated from prior surgery or fracture.

BACKGROUND:Pivot-shift injury commonly results in combined anterior cruciate ligament (ACL)/medial collateral ligament (MCL) injury, yet the contribution of the components of the MCL complex to restraining multiplanar rotatory loads forming critical subcomponents of the pivot shift is not well understood. PURPOSE:To quantify the role of the MCL complex in restraining multiplanar rotatory loads. STUDY DESIGN:Controlled laboratory study. METHODS:A robotic manipulator was used to apply combined valgus and internal rotation torques in a simplified model of the pivot-shift examination in 12 cadaveric knees (49 ± 11 years). Tibiofemoral kinematics were recorded with the ACL intact. Loads borne by the superficial MCL (sMCL), posterior oblique ligament (POL), deep MCL (dMCL), and ACL were determined via the principle of superposition. RESULTS:The POL bore about 50% of the load carried by the ACL in response to the combined torques at 5° and 15° of flexion. The POL bore load during the internal rotation component of the combined torques, while the sMCL carried load during the valgus and internal rotation phases of the simulated pivot. Load in the dMCL was always <10% of the ACL in response to combined valgus and internal rotation torques. CONCLUSION:The POL provides complementary load bearing to the ACL near extension in response to combined torques, which capture key components of the pivot-shift examination. The sMCL resists the valgus component of the maneuver alone, a loading pattern unique from those of the POL and ACL. The dMCL is not loaded during clinical tests of rotational knee stability in the ACL-competent knee. CLINICAL RELEVANCE:Both the sMCL and POL work together with the ACL to resist combined moments, which form key components of the pivot-shift examination.

A multibody model of the knee was developed and the predicted ligament forces and kinematics during passive flexion corroborated subject-specific measurements obtained from a human cadaveric knee that was tested using a robotic manipulator. The model incorporated a novel strategy to estimate the slack length of ligament fibers based on experimentally measured ligament forces at full extension and included multifiber representations for the cruciates. The model captured experimentally measured ligament forces (≤ 5.7 N root mean square (RMS) difference), coupled internal rotation (≤ 1.6 deg RMS difference), and coupled anterior translation (≤ 0.4 mm RMS difference) through 130 deg of passive flexion. This integrated framework of model and experiment improves our understanding of how passive structures, such as ligaments and articular geometries, interact to generate knee kinematics and ligament forces.

BACKGROUND:The femoral insertion of the anterior cruciate ligament (ACL) has direct and indirect fiber types located within the respective high (anterior) and low (posterior) regions of the femoral footprint. HYPOTHESIS:The fibers in the high region of the ACL footprint carry more force and are more isometric than the fibers in the low region of the ACL footprint. STUDY DESIGN:Controlled laboratory study. METHODS:Ten fresh-frozen cadaveric knees were mounted to a robotic manipulator. A 134-N anterior force at 30° and 90° of flexion and combined valgus (8 N·m) and internal (4 N·m) rotation torques at 15° of flexion were applied simulating tests of anterior and rotatory stability. The ACL was sectioned at the femoral footprint by detaching either the higher band of fibers neighboring the lateral intercondylar ridge in the region of the direct insertion or the posterior, crescent-shaped fibers in the region of the indirect insertion, followed by the remainder of the ACL. The kinematics of the ACL-intact knee was replayed, and the reduction in force due to each sectioned portion of insertion fibers was measured. Isometry was assessed at anteromedial, center, and posterolateral locations within the high and low regions of the femoral footprint. RESULTS:With an anterior tibial force at 30° of flexion, the high fibers carried 83.9% of the total anterior ACL load compared with 16.1% in the low fibers (P < .001). The high fibers also carried more anterior force than the low fibers at 90° of flexion (95.2% vs 4.8%; P < .001). Under combined torques at 15° of flexion, the high fibers carried 84.2% of the anterior ACL force compared with 15.8% in the low fibers (P < .001). Virtual ACL fibers placed at the anteromedial portion of the high region of the femoral footprint were the most isometric, with a maximum length change of 3.9 ± 1.5 mm. CONCLUSION:ACL fibers located high within the femoral footprint bear more force during stability testing and are more isometric during flexion than low fibers. CLINICAL RELEVANCE:It may be advantageous to create a "higher" femoral tunnel during ACL reconstruction at the lateral intercondylar ridge.