Citations

Background: Limb asymmetries, as determined through in vivo biomechanical measures, are known risk factors for anterior cruciate ligament (ACL) injury. Previous cadaveric studies have shown a lack of significant differences in ligament strain between contralateral lower extremities when identical kinematics were simulated on specimens. Recent methodological developments have applied in vivo knee kinetics to exert landing forces on cadaveric lower extremities to mimic ACL injury events, but it is unknown whether contralateral limbs fail in a consistent manner during impact simulator testing. Hypothesis: It was hypothesized that contralateral lower extremities would not exhibit side-to-side differences in ligament strains. Furthermore, it was hypothesized that failure loads and failure locations would be independent of limb dominance. Study Design: Controlled laboratory study. Methods: Fourteen pairs of cadaveric lower extremities were obtained from an anatomic donations program (8 female, 6 male; mean ± SD: age, 41.7 ± 8.1 years; mass, 86.8 ± 27.0 kg; body mass index, 29.4 ± 9.0 kg/m 2 ). A mechanical impact simulator was used to re-create the impulse ground-reaction force generated during an in vivo landing task. Ligament strains were recorded by differential variable force transducers implanted on the ACL and medial collateral ligament (MCL). Results: No significant differences were observed in peak ACL or peak MCL strain for 5 loading conditions. Fisher exact tests of independence revealed that limb dominance was independent of both load at failure and failure location. Conclusion: There were no significant differences in ACL and MCL strain values between limb sides during in vitro impact simulation testing. This finding indicates that limb dominance does not influence the failure threshold of the ACL, since there was no significant difference in failure strains. The functional mechanics of the ACL are comparable between contralateral pairs from the same healthy specimen. Clinical Relevance: Injury mechanisms and intra-articular mechanics cannot be ethically studied in an in vivo setting. The current study provides additional insight into limb asymmetry that is observed among athletes in clinical sports medicine settings.

Background: Females are at an increased risk of sustaining noncontact knee ligament injuries as compared with their male counterparts. The kinetics that load the anterior cruciate ligament (ACL) are still under dispute in the literature. Purpose/Hypothesis: The purpose of this study was to determine whether there are differences in knee kinetics between the sexes that lead to greater ACL strain in females when similar external loads are applied during a simulated drop vertical jump landing task. It was hypothesized that female limbs would demonstrate significant differences in knee abduction moment that predispose females to ACL injury when compared with males. Study Design: Controlled laboratory study. Methods: Motion analysis data of 67 athletes who performed a drop vertical jump were collected. The kinematic and kinetic data were used to categorize tertiles of relative risk, and these values were input into a cadaveric impact simulator to assess ligamentous loads during the simulated landing task. Uni- and multiaxial load cells and differential variable reluctance transducer strain sensors were utilized to collect kinetic data and maximum ACL strain for analysis. Conditions of external loads applied to the cadaveric limbs were systematically varied and randomized. Data were analyzed with 2-way repeated-measures analysis of variance and the Fisher exact test. Results: Five kinetic parameters were evaluated. Of the 5 kinetic variables, only knee abduction moment (KAM) demonstrated significant differences in females as compared with males ( F 1,136 = 4.398, P = .038). When normalized to height and weight, this difference between males and females increased in significance ( F 1,136 = 7.155, P = .008). Compared with males, females exhibited a 10.3-N·m increased knee abduction torque at 66 milliseconds postimpact and a 22.3-N·m increased abduction torque at 100 milliseconds postimpact. For loading condition, the condition of “maximum ACL strain” demonstrated a maximum difference of 54.3-N·m increased abduction torque and 74.5-N·m increased abduction torque at 66 milliseconds postimpact. Conclusion: Under the tested conditions, increased external loads led to increased medial knee translation force, knee abduction moment, and external knee moment. Females exhibited greater forces and moments at the knee, especially at KAM, when loaded in similar conditions. As these KAM loads are associated with increased load and strain on the ACL, the sex-based differences observed in the present study may account for a portion of the underlying mechanics that predispose females to ACL injury as compared with males in a controlled simulated athletic task. Clinical Relevance: KAM increases strain to the ACL under clinically representative loading. Additionally, this work establishes the biomechanical characteristics of knee loading between sexes.

Background: Medial meniscus root tears are a common knee injury and can lead to accelerated osteoarthritis, which might ultimately result in a total knee replacement. Purpose: To compare meniscus repair, meniscectomy, and nonoperative treatment approaches among middle-aged patients in terms of osteoarthritis development, total knee replacement rates (clinical effectiveness), and cost-effectiveness. Study Design: Meta-analysis and cost-effectiveness analysis. Methods: A systematic literature search was conducted. Progression to osteoarthritis was pooled and meta-analyzed. A Markov model projected strategy-specific costs and disutilities in a cohort of 55-year-old patients presenting with a meniscus root tear without osteoarthritis at baseline. Failure rates of repair and meniscectomy procedures and disutilities associated with osteoarthritis, total knee replacement, and revision total knee replacement were accounted for. Utilities, costs, and event rates were based on literature and public databases. Analyses considered a time frame between 5 years and lifetime and explored the effects of parameter uncertainty. Results: Over 10 years, meniscus repair, meniscectomy, and nonoperative treatment led to 53.0%, 99.3%, and 95.1% rates of osteoarthritis and 33.5%, 51.5%, and 45.5% rates of total knee replacement, respectively. Meta-analysis confirmed lower osteoarthritis and total knee replacement rates for meniscus repair versus meniscectomy and nonoperative treatment. Discounted 10-year costs were $22,590 for meniscus repair, as opposed to $31,528 and $25,006 for meniscectomy and nonoperative treatment, respectively; projected quality-adjusted life years were 6.892, 6.533, and 6.693, respectively, yielding meniscus repair to be an economically dominant strategy. Repair was either cost-effective or dominant when compared with meniscectomy and nonoperative treatment across a broad range of assumptions starting from 5 years after surgery. Conclusion: Repair of medial meniscus root tears, as compared with total meniscectomy and nonsurgical treatment, leads to less osteoarthritis and is a cost-saving intervention. While small confirmatory randomized clinical head-to-head trials are warranted, the presented evidence seems to point relatively clearly toward adopting meniscus repair as the preferred initial intervention for medial meniscus root tears.

AbstractInjury to the posterolateral corner (PLC) of the knee can lead to both varus and rotational instability. Multiple PLC reconstruction techniques have been described, including one-tailed graft (fibula-based constructs) or two-tailed graft (combined fibula- and tibia-based constructs). The purpose of our study was to evaluate the clinical outcomes of anatomical two-tailed graft reconstruction of the PLC in the setting of multiligament knee injuries (MKLIs) with grade III varus instability. Patients were identified through a prospective MLKI database between 2004 and 2013. Patients who received fibular collateral ligament and PLC reconstructions using a two-tailed graft and had a minimum follow-up of 2 years were included. Patients were assessed for clinical laxity grade, range of motion, and functional outcomes using Lysholm and International Knee Documentation Committee (IKDC) scores. Twenty patients (16 male, 4 female) with a mean age of 30.7 (range: 16–52) and a mean follow-up of 52.2 months (range: 24–93 months) were included. Knee dislocation (KD) grades included: 4 KD-1, 10 KD 3-L, 5 KD-4, and 1 KD-5. No patients had isolated PLC injuries. Mean IKDC and Lysholm score were 73.1 ± 25.8 and 78 ± 26, respectively. Mean range of motion was –1.1 to 122.8. In full extension, two patients (10%) had grade 1 laxity to varus stress. In 30 degrees of knee flexion, five (25%) patients had grade 1 laxity, and two (10%) had grade 2 laxity. Anatomical two-tailed PLC reconstruction can reliably restore varus stability when performed on patients with MLKIs and type C posterolateral instability with hyperextension external rotation recurvatum deformity. Satisfactory functional outcome scores were achieved in the majority of patients. This study supports the use of an anatomical two-tailed PLC reconstruction in the multiligament injured knee. The level of evidence is IV, case series.

AbstractPurposeDevelop a framework to quantify the size, location and severity of femoral and acetabular‐sided cartilage and labral damage observed in patients undergoing hip arthroscopy, and generate a database of individual defect parameters to facilitate future research and treatment efforts.MethodsThe size, location, and severity of cartilage and labral damage were prospectively collected using a custom, standardized post‐operative template for 100 consecutive patients with femoroacetabular impingement syndrome. Chondrolabral junction damage, isolated intrasubstance labral damage, isolated acetabular cartilage damage and femoral cartilage damage were quantified and recorded using a combination of Beck and ICRS criteria. Radiographic measurements including alpha angle, head–neck offset, lateral centre edge angle and acetabular index were calculated and compared to the aforementioned chondral data using a multivariable logistic regression model and adjusted odd’s ratio. Reliability among measurements were assessed using the kappa statistic and intraclass coefficients were used to evaluate continuous variables.ResultsDamage to the acetabular cartilage originating at the chondrolabral junction was the most common finding in 97 hips (97%) and was usually accompanied by labral damage in 65 hips (65%). The width (p = 0.003) and clock‐face length (p = 0.016) of the damaged region both increased alpha angle on anteroposterior films. 10% of hips had femoral cartilage damage while only 2 (2%) of hips had isolated defects to either the acetabular cartilage or labrum. The adjusted odds of severe cartilage (p = 0.022) and labral damage (p = 0.046) increased with radiographic cam deformity but was not related to radiographic measures of acetabular coverage.ConclusionsDamage at the chondrolabral junction was very common in this hip arthroscopy cohort, while isolated defects to the acetabular cartilage or labrum were rare. These data demonstrate that the severity of cam morphology, quantified through radiographic measurements, is a primary predictor of location and severity of chondral and labral damage and focal chondral defects may represent a unique subset of patients that deserve further study.Level of evidenceIV.

A “perineal” branch of the sciatic nerve has been visualized during surgery, but there is currently no description of this nerve branch in the literature. Our study investigates the presence and frequency of occurrence of perineal innervation by the sciatic nerve and characterizes its anatomy in the posterior thigh. Fifteen cadavers were obtained for dissection. Descriptive results were recorded and analyzed statistically. Twenty‐one sciatic nerves were adequately anatomically preserved. Six sciatic nerves contained a perineal branch. Five sciatic nerves had a branch contributing to the perineal branch of the posterior femoral cutaneous (PFC) nerve. In specimens with adequate anatomical preservation, the perineal branch of the sciatic nerve passed posterior to the ischial tuberosity in three specimens and posterior to the conjoint tendon of the long head of biceps femoris and semitendinosus muscles (conjoint tendon) in one. In specimens in which the perineal branch of the PFC nerve received a contribution from the sciatic nerve, the branch passed posterior to the sacrotuberous ligament in one case and posterior to the conjoint tendon in three. Unilateral nerve anatomy was found to be a poor predictor of contralateral anatomy (Cohen's kappa = 0.06). Our study demonstrates for the first time the presence and frequency of occurrence of the perineal branch of the sciatic nerve and a sciatic contribution to the perineal branch of the PFC nerve. Clinicians should be cognizant of this nerve and its varying anatomy so their practice is better informed. Clin. Anat. 31:357–363, 2018. © 2018 Wiley Periodicals, Inc.

Background: Patellar height has long been considered a risk factor for patellofemoral instability. However, recent pediatric literature demonstrated a reduction in patellar height measurements following medial patellofemoral ligament (MPFL) reconstruction. Purpose: To assess the mean change in patellar height and the percentage of skeletally mature patients with patellar height ratios reduced to within-normal limits following MPFL reconstruction. Study Design: Case series; Level of evidence, 4. Methods: Adult patients undergoing primary MPFL reconstruction for recurrent lateral patellar instability between 2005 and 2013 were identified. Pre- and postoperative (within 1 year of surgery) lateral knee radiographs were assessed for patellar height indices, including Caton-Deschamps, Blackburne-Peel, and Insall-Salvati ratios. The change in patellar height and the number of patients reduced from abnormal to normal patellar height ratios following MPFL reconstruction were assessed. Results: Overall, 32 adult patients were included in the study, with a mean age of 25.7 years (range, 18-55 years). There were 21 women (66%) and 11 men (34%). Insall-Salvati, Blackburne-Peel, and Caton-Deschamps ratios all demonstrated significant reductions in patellar height between pre- and postoperative lateral knee radiographs ( P < .001). All 3 indices showed a reduction in the number of patients meeting the criteria for patella alta following MPFL reconstruction. A total of 64% of patients had an abnormal preoperative Caton-Deschamps ratio reduced to within normal limits postoperatively. Conclusion: MPFL reconstruction provides a consistent reduction in patellar height measurements. The Caton-Deschamps ratio was reduced to the reference range following MPFL reconstruction in 64% of patients with preoperative patella alta. Surgeons treating patellofemoral instability should expect a reduction in patellar height after ligament reconstruction, which may affect the need for more invasive distalization procedures.

Background: There is a paucity of clinical information to guide the treatment of a combined anterior cruciate ligament (ACL) tear and Segond fracture. Purpose: To compare clinical outcomes, graft failure rates, and activity levels between patients undergoing ACL reconstruction (ACLR) with and without an untreated Segond fracture at a minimum 2-year follow-up. Study Design: Cohort study; Level of evidence, 3. Methods: This study included a group of patients with a combined ACL tear/untreated Segond fracture that was matched based on age, sex, body mass index, and graft type to a control group of patients with an ACL tear and no Segond fracture. All patients were treated with ACLR alone between the years of 2000 and 2015. The diagnosis of a Segond fracture, or bony avulsion of the anterolateral complex, was made by radiographic analysis. Data regarding the initial injury, surgical intervention, and physical examination findings were recorded. Clinical and functional outcomes were obtained using physical examination results, International Knee Documentation Committee (IKDC) subjective scores, and Tegner activity levels. Results: Twenty patients (16 male, 4 female) with a combined ACL tear/untreated Segond fracture with a mean age of 26.3 years (range, 13-44 years) were matched to a control group of 40 patients (32 male, 8 female) with an ACL tear and no Segond fracture with a mean age of 26.4 years (range, 13-47 years). The study group was followed for a mean of 59.1 months (range, 24-180 months) and the control group for a mean of 55.5 months (range, 24-120 months). The mean IKDC score was 86.5 (range, 54-100) for the study group compared with 93.0 (range, 54-100) for the control group ( P = .03). The graft rupture rate was 10% for both groups ( P = .97). The mean time to rupture was 33.0 months (range, 21-45 months) in the study group and 63.5 months (range, 39-88 months) in the control group ( P = .24). Patients in the study group had significantly more anteroposterior instability by preoperative Lachman testing than those in the control group (control group: 0 normal, 3 grade 1+, 37 grade 2+, 0 grade 3+; study group: 0 normal, 1 grade 1+, 10 grade 2+, 9 grade 3+; P = .0001). There was no significant difference between the 2 groups in regard to postoperative Lachman testing (control group: 35 normal, 3 grade 1+, 2 grade 2+, 0 grade 3+; study group: 17 normal, 3 grade 1+, 0 grade 2+, 0 grade 3+; P = .31). Patients in the study group had significantly more instability by preoperative pivot-shift testing than those in the control group (control group: 0 normal, 7 grade 1+, 33 grade 2+, 0 grade 3+; study group: 1 normal, 1 grade 1+, 11 grade 2+, 7 grade 3+; P = .0003). No significant difference was found between the 2 groups for postoperative pivot-shift testing (control group: 36 normal, 2 grade 1+, 2 grade 2+, 0 grade 3+; study group: 18 normal, 1 grade 1+, 1 grade 2+, 0 grade 3+; P = .61) or final Tegner activity level (median, 6). Conclusion: At midterm follow-up, patients undergoing ACLR with and without a Segond fracture had similar pivot-shift test results, graft failure rates, and activity levels. The IKDC score was statistically worse in the patients with a combined ACL tear/untreated Segond fracture, but the difference was less than the minimal clinically important difference for the IKDC score. These findings suggest that patients with a combined ACL tear/untreated Segond fracture can have comparable outcomes to patients with an ACL tear and no Segond fracture when treated with ACLR alone.

Objective Distal femoral varus osteotomy (DFVO) is an effective treatment for unloading valgus knee malalignment; however, there is limited evidence on the ability for patients to return to athletics following this procedure. The purpose of this study is to report the functional outcomes and rate of return to sport for athletes that underwent DFVO. Design A consecutive series of athletes that had undergone DFVO were retrospectively reviewed. Radiographs were assessed to determine preoperative and postoperative alignment. Institutional registries were used to collect preoperative and postoperative Marx Activity Scale, International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form scores, and return to sport. Results Thirteen patients (8 males, 5 females) with a mean age of 24 years (range 17-35 years) and a mean follow-up of 43 months (range 24-74 months) were included in the study. Six patients underwent medial closing wedge DFVO versus 7 patients who underwent lateral opening wedge DFVO. Nine of 13 had concomitant chondral, meniscal, or ligamentous procedures performed. The mean alignment correction was 8° (range 5°-13°). All patients were able to successfully return to sport at a mean of 11 months (range 9-13 months). Furthermore, all 13 patients demonstrated an improvement in both Marx Activity Scale (4-11; P < 0.01) and IKDC scores (53-89; P < 0.01) after surgery. Conclusions Correction of valgus knee malalignment through DFVO—either medial closing wedge or lateral opening wedge—can reliably result in improvement in function and return to sport. Concomitant chondral, meniscal, and ligamentous pathology should be addressed.