Adult Prg4+ progenitors repair long-term articular cartilage wounds in vivo.

The identity and origin of the stem/progenitor cells for adult joint cartilage repair remain unknown, impeding therapeutic development. Simulating the common therapeutic modality for cartilage repair in humans, i.e., full-thickness microfracture joint surgery, we combined the mouse full-thickness injury model with lineage tracing and identified a distinct skeletal progenitor cell type enabling long-term (beyond 7 days after injury) articular cartilage repair in vivo. Deriving from a population with active Prg4 expression in adulthood while lacking aggrecan expression, these progenitors proliferate, differentiate to express aggrecan and type II collagen, and predominate in long-term articular cartilage wounds, where they represent the principal repair progenitors in situ under native repair conditions without cellular transplantation. They originate outside the adult bone marrow or superficial zone articular cartilage. These findings have implications for skeletal biology and regenerative medicine for joint injury repair.

Core Muscle Injury: Evaluation and Treatment in the Athlete.

BACKGROUND: Pain in the groin region, where the abdominal musculature attaches to the pubis, is referred to as a "sports hernia,""athletic pubalgia," or "core muscle injury" and has become a topic of increased interest due to its challenging diagnosis. Identifying the cause of chronic groin pain is complicated because significant symptom overlap exists between disorders of the proximal thigh musculature, intra-articular hip pathology, and disorders of the abdominal musculature. PURPOSE: To present a comprehensive review of the pathoanatomic features, history and physical examination, and imaging modalities used to make the diagnosis of core muscle injury. STUDY DESIGN: Narrative and literature review; Level of evidence, 4. METHODS: A comprehensive literature search was performed. Studies involving the diagnosis, treatment, and rehabilitation of athletes with core muscle injury were identified. In addition, the senior author's extensive experience with the care of professional, collegiate, and elite athletes was analyzed and compared with established treatment algorithms. RESULTS: The differential diagnosis of groin pain in the athlete should include core muscle injury with or without adductor longus tendinopathy. Current scientific evidence is lacking in this field; however, consensus regarding terms and treatment algorithms was facilitated with the publication of the Doha agreement in 2015. Pain localized proximal to the inguinal ligament, especially in conjunction with tenderness at the rectus abdominis insertion, is highly suggestive of core muscle injury. Concomitant adductor longus tendinopathy is not uncommon in these athletes and should be investigated. The diagnosis of core muscle injury is a clinical one, although dynamic ultrasonography is becoming increasingly used as a diagnostic modality. Magnetic resonance imaging is not always diagnostic and may underestimate the true extent of a core muscle injury. Functional rehabilitation programs can often return athletes to the same level of play. If an athlete has been diagnosed with athletic pubalgia and has persistent symptoms despite 12 weeks of nonoperative treatment, a surgical repair using mesh and a relaxing myotomy of the conjoined tendon should be considered. The most common intraoperative finding is a deficient posterior wall of the inguinal canal with injury to the distal rectus abdominis. Return to play after surgery for an isolated sports hernia is typically allowed at 4 weeks; however, if an adductor release is performed as well, return to play occurs at 12 weeks. CONCLUSION: Core muscle injury is a diagnosis that requires a high level of clinical suspicion and should be considered in any athlete with pain in the inguinal region. Concurrent adductor pathology is not uncommon.

Single-Stage Revision Anterior Cruciate Ligament Reconstruction Using the Stacked Screws Technique.

Single-stage revision anterior cruciate ligament (ACL) reconstruction is preferable to 2-stage revision, when possible, as it avoids an additional surgery and recovery period. Malpositioned and/or widened bone tunnels are a common cause of ACL reconstruction failure and are challenging to manage in revision reconstructions. The "stacked screws construct" fills the previous malpositioned tunnels and bone voids with an oversized biocomposite screw as graft material. The revised tunnel can then be drilled in an anatomic "primary" location, even partially overlapping the filler screw. This technique simplifies tunnel management in revision ACL reconstruction.

Patient-Reported Outcomes After Multiple-Revision ACL Reconstruction: Good but Not Great.

PURPOSE: To evaluate the patient-reported and objective functional outcomes of patients undergoing multiple-revision anterior cruciate ligament (ACL) reconstruction surgery. The secondary purpose was to determine failure rates and factors associated with failure, with a focus on posterior tibial slope. METHODS: All patients who underwent a repeat revision ACL reconstruction with a single surgeon over a 13-year period were identified. Chart data were obtained, including radiographic findings, operative details and findings, and postoperative examination findings. Failure was defined as subjective instability with evidence of graft incompetence on physical examination and MRI. Patients completed the International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC-SKF) and Tegner Activity Level Scale. Patients who had outcomes scores completed a minimum of 2 years postoperatively were included. RESULTS: Fourteen patients were available for follow-up; 12 underwent secondary revision procedures, and 2 underwent tertiary revisions. Three patients (21%) had subsequent failure of the revision graft with mean time to failure of 27 months. Posterior tibial slope was significantly higher in the failures than in the nonfailures (13.3˚; 95% CI 10.1-16.6 versus 10.1˚; 95% CI 6.7-11.4; P = 0.049). Eleven patients completed outcomes measures at a mean of 42 months postoperatively (range 24-79 months). The mean Tegner activity score was 6.3 at follow-up, compared with 8.3 prior to the original ACL injury. The mean IKDC-SKF score was 70 at follow-up. CONCLUSION: Multiple revision ACL reconstruction surgery appears to have reasonable functional outcomes but is associated with a relatively high failure rate. Activity level following repeat revision surgery is diminished compared to the preinjury state, but most patients are able to return to recreational sports. LEVEL OF EVIDENCE: Therapeutic Study, Level IV.

Editorial Commentary: Graft Orientation in Anterior Cruciate Ligament Reconstruction-Does It Really Matter?

The search for an isometric, anatomic, biomechanically optimal anterior cruciate ligament (ACL) reconstruction remains elusive. To better approximate the native ACL, surgeons have used a host of different graft options and repair techniques. Surgical techniques involving single-tunnel and double-tunnel (or even triple-tunnel!) fixation sites have been used in an attempt to re-create the "2 (or more) bundles" of the ACL. Transtibial and independent femoral drilling techniques are used in an effort to create a more "anatomic" femoral tunnel placement. Once the anatomic femoral attachment site is identified, there is then a debate on how best to "fill" the attachment site with the surgical graft. These are all important discussions and debates, but one question remains . . . Does any of it really matter?

Biomechanics Following Isolated Posterolateral Corner Reconstruction Comparing a Fibular-Based Docking Technique With a Tibia and Fibular-Based Anatomic Technique Show Either Technique is Acceptable.

PURPOSE: To analyze the biomechanical integrity of 2 posterolateral corner (PLC) reconstruction techniques using a sophisticated robotic biomechanical system that enables analysis of joint kinematics under dynamic external loads. METHODS: Eight cadaveric human knee specimens were tested. Five N·m external torque followed by 5 N·m varus torque was dynamically applied to each specimen. The 6 degrees of freedom kinematics of the joint were measured in 4 states (intact, PLC-deficient, fibular-based docking, and anatomic PLC reconstructed) at 30°, 60°, and 90° of flexion. Tibial external rotation (ER) and varus rotation (VR) were compared. RESULTS: Under external torque, ER significantly increased from the intact state to the PLC-deficient state across all flexion angles. At 30° of flexion, ER was not significantly different between the intact state (19.9°) and fibular-based (18.7°, P = .336) and anatomic reconstructions (14.9°, P = .0977). At 60°, ER was not significantly different between the intact state and fibular-based reconstruction (22.4°, compared with 19.8° in intact; P = .152) but showed overconstraint after anatomic reconstruction (15.7°; P = .0315). At 90°, ER was not significantly different between the intact state and anatomic reconstruction (15.4°, compared with 19.7° in intact; P = .386) but was with the fibular-based technique (23.5°; P = .0125). CONCLUSION: Both a fibular-based docking technique and an anatomic technique for isolated PLC reconstruction provided appropriate constraint through most tested knee range of motion, yet the fibular-based docking technique underconstrained the knee at 90°, and the anatomic reconstruction overconstrained the knee at 60°. Biomechanically, either technique may be considered for surgical treatment of high-grade isolated PLC injuries. CLINICAL RELEVANCE: This biomechanical study utilizing clinically-relevant dynamic forces on the knee shows that either a simplified fibular-based docking technique or a more complex anatomic technique may be considered for surgical treatment of high-grade isolated PLC injuries.

Arthroscopic Circumferential Labral Repair for Patients With Multidirectional Instability: A Comparative Outcome Study.

BACKGROUND: Circumferential tears of the glenohumeral labrum are an uncommon injury, comprising 2.4% of all labral lesions. Currently, the clinical outcomes of arthroscopic circumferential labral repair for patients with instability and combined anterior, posterior, and superior labral tears are not well-known. HYPOTHESIS: Patients treated with arthroscopic circumferential shoulder labral repairs will have inferior clinical outcomes and higher failure rates compared with patients who have isolated arthroscopic anterior labral repairs. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective cohort study was performed to identify patients aged 18 years and older who underwent circumferential arthroscopic stabilization for recurrent instability as compared with an age-matched control group of arthroscopic primary anterior labral repairs. Age at surgery, American Shoulder and Elbow Surgeons (ASES) Standardized Shoulder Assessment Form score, Simple Shoulder Test (SST) score, 12-Item Short Form Health Survey (SF-12) score (mental and physical), and overall patient satisfaction with surgery were assessed for each group. RESULTS: A total of 35 consecutive patients (36 shoulders) who underwent an arthroscopic 360° circumferential labral repair were compared with a matched group of 31 patients who underwent an isolated arthroscopic anterior labral repair. The mean follow-up period was 34.3 and 56.8 months, respectively. No significant difference was found between the 2 groups for overall satisfaction with the surgery or recurrent instability. At the time of the follow-up survey, 22% of the patients experienced pain and 25% of the patients experienced instability in the circumferential repair group, whereas 15% of the patients experienced some level of pain and 30% of patients experienced a subjective sense of subtle instability in the isolated repair group. The ASES scores were 87.3 in the combined labral repair group and 93.3 in the isolated anterior group (P = .35), SST scores were 10.7 and 11.3 (P = .70), SF-12 mental scores were 54.6 and 56.8 (P = .80), SF-12 physical scores were 53.2 and 54.2 (P = .98), and age at time of the surgery was 26.7 and 24.6 years (P = .33), respectively. There was no difference between the 2 groups in pre- and postoperative range of motion (P > .05). CONCLUSION: There was no difference in shoulder stability and function in patients after 360° combined labral repairs versus anterior labral repair alone. With proper patient selection, patients can expect similar outcomes despite the more extensive surgical procedure and complex postoperative rehabilitation protocol for circumferential repairs.

A Prospective, Blinded, Multicenter Clinical Trial to Compare the Efficacy, Accuracy, and Safety of In-Office Diagnostic Arthroscopy With Magnetic Resonance Imaging and Surgical Diagnostic Arthroscopy.

PURPOSE: The purpose of this study was to compare the efficacy, accuracy, and safety of in-office diagnostic arthroscopy with magnetic resonance imaging (MRI) and surgical diagnostic arthroscopy. METHODS: A prospective, blinded, multicenter, clinical trial was performed on 110 patients, ages 18 to 75 years, who presented with knee pain. The study period was April 2012 to April 2013. Each patient underwent a physical examination, an MRI, in-office diagnostic imaging, and a diagnostic arthroscopic examination in the operating room. The attending physician completed clinical report forms comparing the in-office arthroscopic examination and surgical diagnostic arthroscopy findings on each patient. Two blinded experts, unaffiliated with the clinical care of the study's subjects, reviewed the in-office arthroscopic images and MRI images using the surgical diagnostic arthroscopy images as the "control" group comparison. Patients were consecutive, and no patients were excluded from the study. RESULTS: In this study, the accuracy, sensitivity, and specificity of in-office arthroscopy was equivalent to surgical diagnostic arthroscopy and more accurate than MRI. When comparing in-office arthroscopy with surgical diagnostic arthroscopy, all kappa statistics were between 0.766 and 0.902. For MRI compared with surgical diagnostic arthroscopy, kappa values ranged from a low of 0.130 (considered "slight" agreement) to a high of 0.535 (considered "moderate" agreement). The comparison of MRI to in-office arthroscopy showed very similar results as the comparison of MRI with surgical diagnostic arthroscopy, ranging from a low kappa of 0.112 (slight agreement) to a high of 0.546 (moderate agreement). There were no patient-related or device-related complications related to the use of in-office arthroscopy. CONCLUSIONS: Needle-based diagnostic imaging that can be used in the office setting is statistically equivalent to surgical diagnostic arthroscopy with regard to the diagnosis of intra-articular, nonligamentous knee joint pathology. In-office diagnostic imaging can provide a more detailed and accurate diagnostic assessment of intra-articular knee pathology than MRI. Based on the study results, in-office diagnostic imaging provides a safe, accurate, real-time, minimally invasive diagnostic modality to evaluate intra-articular pathology without the need for surgical diagnostic arthroscopy or high-cost imaging. LEVEL OF EVIDENCE: Level II, comparative prospective trial.

Variability in the Clock Face View Description of Femoral Tunnel Placement in ACL Reconstruction Using MRI-Based Bony Models.

Though controversial, the "clock face view" of the intercondylar notch remains a way some surgeons communicate regarding placement of the femoral tunnel in anterior cruciate ligament reconstruction. The purpose of this study was to quantify the differences in angle measurement between several previous descriptions of the clock face view by using a new reference standard. Three-Tesla magnetic resonance imaging (MRI) was used to scan 10 human knees to create three-dimensional MRI-based bony models which were used for measurements. A standardized clock face view was developed with the knee flexed to 90° using the junction of the cartilage and cortex of the medial and lateral surfaces of medial and lateral femoral condyles as the 3 o'clock and 9 o'clock, respectively, with the 12 o'clock established as the midpoint of the roof of the intercondylar notch. With the knee viewed at 90° of flexion, an "idealized" femoral tunnel position was plotted on the medial wall of the lateral femoral condyle at 30° (corresponding to the 10 o'clock or 2 o'clock position). The clock faces as described by Edwards et al, Heming et al, and Mochizuki et al were each then overlaid on this same model and the difference in measurement calculated. The average angles measured when the previously described clock faces were projected onto the idealized clock face view comparing a mark made at 30° were 47.7°, 7.2°, and 49.8° for the methods described by Edwards et al, Heming et al, and Mochizuki et al, respectively (all p < 0.001). Significant variation exists between angle measurements in simulated femoral tunnel placement based on the varying descriptions of the intercondylar clock face.

An In Vivo Prediction of Anisometry and Strain in Anterior Cruciate Ligament Reconstruction - A Combined Magnetic Resonance and Dual Fluoroscopic Imaging Analysis.

PURPOSE: To evaluate the in vivo anisometry and strain of theoretical anterior cruciate ligament (ACL) grafts in the healthy knee using various socket locations on both the femur and tibia. METHODS: Eighteen healthy knees were imaged using magnetic resonance imaging and dual fluoroscopic imaging techniques during a step-up and sit-to-stand motion. The anisometry of the medial aspect of the lateral femoral condyle was mapped using 144 theoretical socket positions connected to an anteromedial, central, and posterolateral attachment site on the tibia. The 3-dimensional wrapping paths of each theoretical graft were measured. Comparisons were made between the anatomic, over the top (OTT), and most-isometric (isometric) femoral socket locations, as well as between tibial insertions. RESULTS: The area of least anisometry was found in the proximal-distal direction just posterior to the intercondylar notch. The most isometric attachment site was found midway on the Blumensaat line with approximately 2% and 6% strain during the step-up and sit-to-stand motion, respectively. Posterior femoral attachments resulted in decreased graft lengths with increasing flexion angles, whereas anterodistal attachments yielded increased lengths with increasing flexion angles. The anisometry of the anatomic, OTT and isometric grafts varied between tibial insertions (P < .001). The anatomic graft was significantly more anisometric than the OTT and isometric graft at deeper flexion angles (P < .001). CONCLUSIONS: An area of least anisometry was found in the proximal-distal direction just posterior to the intercondylar notch. ACL reconstruction at the isometric and OTT location resulted in nonanatomic graft behavior, which could overconstrain the knee at deeper flexion angles. Tibial location significantly affected graft strains for the anatomic, OTT, and isometric socket location. CLINICAL RELEVANCE: This study improves the knowledge on ACL anisometry and strain and helps surgeons to better understand the consequences of socket positioning during intra-articular ACL reconstruction.

Anteromedial and posterolateral graft kinematics of a double-bundle ACL reconstruction: a 3D computer simulation.

BACKGROUND: The posterolateral graft has been reported to fail more frequently than the anteromedial graft in double-bundle ACL reconstructions. This study investigated the graft kinematics using a 3D modelling technique. METHODS: Twenty subjects performed a stair-ascending activity under dual fluoroscopy surveillance. A double-bundle ACL reconstruction was simulated on those healthy knees using an anteromedial portal technique. The graft-tunnel interaction was described using the graft-tunnel angle and the range of the graft-tunnel edge contact (GTEC). RESULTS: The femoral graft-tunnel angle of the anteromedial/posterolateral graft was 97.6 ± 7.5/100.7 ± 7.7° and the tibial graft-tunnel angle was 158.8 ± 6.5/146.5 ± 8.9° at knee extension. The femoral GTEC ranges were 23.2 ± 5.3-28.1 ± 7.6° for both grafts and the tibial GTEC ranges were 27.3 ± 2.2-34.5 ± 2.1° during stair-ascending. CONCLUSION: The femoral graft-tunnel angle was larger than on the tibial side and the GTEC angles influenced the PL graft more, implying that grafts may experience a less optimal biomechanical environment at the femoral tunnels.

Articular cartilage of the knee 3 years after ACL reconstruction. A quantitative T2 relaxometry analysis of 10 knees.

BACKGROUND AND PURPOSE: T1ρ or T2 relaxation imaging has been increasingly used to evaluate the cartilage of the knee. We investigated the cartilage of ACL-reconstructed knees 3 years after surgery using T2 relaxation times. PATIENTS AND METHODS: 10 patients with a clinically successful unilateral ACL reconstruction were examined 3 years after surgery. Multiple-TE fast-spin echo sagittal images of both knees were acquired using a 3T MRI scanner for T2 mapping of the tibiofemoral cartilage. T2 values of the superficial and deep zones of the tibiofemoral cartilage were analyzed in sub-compartmental areas and compared between the ACL-reconstructed and uninjured contralateral knees. RESULTS: Higher T2 values were observed in 1 or more sub-compartmental areas of each ACL-reconstructed knee compared to the uninjured contralateral side. Most of the T2 increases were observed at the superficial zones of the cartilage, especially at the medial compartment. At the medial compartment of the ACL-reconstructed knee, the T2 values of the femoral and tibial cartilage were increased by 3-81% compared to the uninjured contralateral side, at the superficial zones of the weight-bearing areas. T2 values in the superficial zone of the central medial femoral condyle differed between the 2 groups (p = 0.002). INTERPRETATION: The articular cartilage of ACL-reconstructed knees, although clinically satisfactory, had higher T2 values in the superficial zone of the central medial femoral condyle than in the uninjured contralateral side 3 years after surgery. Further studies are warranted to determine whether these patients would undergo cartilage degeneration over time.

Patient Outcomes and Predictors of Success After Revision Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Patient outcomes and predictors of success after revision anterior cruciate ligament (ACL) reconstruction are currently limited in the literature. Existing studies either have a small study size or are difficult to interpret because of the multiple surgeons involved in the care of the study sample. PURPOSE: To determine patient outcomes and predictors of success or failure after a single-stage revision ACL reconstruction by a single fellowship-trained senior surgeon at a single institution. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 78 patients who underwent revision ACL reconstruction by a single surgeon from 2010 to 2014 were contacted and available for follow-up. The mean time from revision procedure to follow-up was 52 months. Those patients who were able to participate in the study sent in a completed Tegner activity level scale, International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, and IKDC Current Health Assessment Form. The patients' medical records were also thoroughly reviewed. RESULTS: Five patients had subsequent failure after revision surgery. The median Tegner score was 6 at follow-up, and the mean subjective IKDC score was 72.5. There was no statistically significant difference in outcome scores when comparing revision graft type, body mass index, sex, need for bone grafting, and time from failure to revision. Patients with failures after primary ACL reconstruction secondary to a traumatic event were found to have statistically significantly higher IKDC scores (mean, 76.6) after revision when compared with nontraumatic failures (mean, 67.1), even when controlling for confounders (P < .017). CONCLUSION: Revision ACL reconstruction is effective in improving patient activity levels and satisfaction. However, the subjective IKDC results are quite variable and likely based on multiple factors. Patients with traumatic injuries contributing to graft failure after primary ACL reconstruction had a statistically significantly, although not clinically significant, higher IKDC score after revision surgery compared with nontraumatic failures. These data may be useful when counseling a patient on whether to pursue revision ACL reconstruction surgery.

Posteromedial knee friction syndrome: an entity with medial knee pain and edema between the femoral condyle, sartorius and gracilis.

OBJECTIVE: To describe MRI features of an entity consisting of medial knee pain and edema between the posteromedial femoral condyle (PMFC), sartorius and/or gracilis tendons and determine whether reduced tendon-bone distances may account for these findings. METHODS: We retrospectively identified MRI cases of edema between the PMFC, sartorius and/or gracilis tendons (25 subjects, 26 knees). Two musculoskeletal radiologists independently graded edema and measured the sartorius- and gracilis-PMFC distances and knee flexion angle. Age- and gender-matched subjects with normal knee MRIs (27 subjects, 27 knees) served as controls for measurements. Statistical analyses compared abnormal to control subjects. RESULTS: Sartorius-PMFC and gracilis-PMFC spaces were narrower in abnormal compared to control subjects (1.6 ± 1.0 vs. 2.1 ± 1.2 mm, P = 0.04; 2.3 ± 2.0 vs. 4.6 ± 3.0 mm, P = 0.002, respectively). The knee flexion angle was similar between groups (P > 0.05). In subjects with clinical information, medial knee pain was the main complaint in 58 % (15/26) of abnormal subjects, with 42 % (11/26) having clinical suspicion of medial meniscal tear. Edema between the PMFC, sartorius and/or gracilis was mild in 54 % (14/26), moderate in 35 % (9/26) and severe in 12 % (3/26), and it was most frequent deep to both the sartorius and gracilis (50 %, 13/26). CONCLUSIONS: Edema between the PMFC, sartorius and/or gracilis tendons identified on knee MRI may be associated with medial knee pain and may represent a friction syndrome.

T2 relaxometry of the infrapatellar fat pad after arthroscopic surgery.

OBJECTIVE: To investigate the T2 relaxation values of the infrapatellar fat pad (IFP) after arthroscopic surgery. MATERIALS AND METHODS: This study was approved by the institutional review board; all individuals signed informed consent. We performed MRI in 16 knees from 8 subjects. Prior to imaging, each subject had unilateral arthroscopic knee surgery and an asymptomatic non-operated contralateral knee. We used a 10-echo multiple-TE fast-spin echo pulse sequence for creation of T2 relaxation time maps. Two musculoskeletal radiologists independently placed regions of interest in the IFP, suprapatellar subcutaneous and deep intermuscular adipose tissue. Qualitative assessments were performed to assess fibrotic changes affecting patellar retinaculum and IFP. Statistical analyses of T2 values determined differences between groups, correlation with time after surgery, and cut-off values to differentiate groups. RESULTS: The average time between arthroscopy and imaging was 3.5 ± 0.4 years. IFP of knees with prior surgery had significantly shorter mean T2 values (133 ± 14 ms) compared with control knees (147 ± 8 ms, P = 0.03). There was no significant difference between operated and control knees regarding T2 values of suprapatellar subcutaneous (P = 0.3) or deep intermuscular adipose tissue (P = 0.2). There was no correlation between IFP T2 values and time after surgery (P > 0.2). IFP T2 values ≤ 139 ms had 75 % sensitivity and 88 % specificity in identifying prior arthroscopy. CONCLUSION: Shortening of T2 relaxation values is present in IFP chronically after arthroscopic surgery and may be an indicator of adipose tissue fibrosis.

Open Patellar Tendon Debridement for Treatment of Recalcitrant Patellar Tendinopathy: Indications, Technique, and Clinical Outcomes After a 2-Year Minimum Follow-up.

BACKGROUND: Patellar tendinopathy can be treated surgically for patients that have failed at least 1 year of nonoperative treatment who continue to have debilitating symptoms. Patellar tendinopathy can cause significant functional deficits, yet little has been reported about the operative treatment of patellar tendinopathy. HYPOTHESIS: A combined arthroscopic and open surgical technique for the treatment of recalcitrant patellar tendinopathy results in an improvement in function and pain at a minimum 2-year follow-up. The purpose of this study was to present the indications, combined surgical technique, rehabilitation protocol, and the 2-year minimum follow-up results of the operative treatment of recalcitrant patellar tendinopathy. STUDY DESIGN: Retrospective case series. METHODS: A retrospective review was performed of all patients who underwent a surgical primary patellar tendon debridement for recalcitrant patellar tendinopathy by a single surgeon between July 1999 and December 2005. Every patient failed at least 1 year of nonoperative treatment. Patients were excluded from the study if they had previous open knee surgery. Validated patient-reported outcome scores were used to assess function and pain levels pre- and postoperatively (Lysholm, International Knee Documentation Committee, Tegner activity, and visual analog pain score). RESULTS: Thirty-four consecutive patients (37 consecutive cases) with mean follow-up 3.8 ± 1.6 years (range, 2-7.6 years) underwent the procedure with no complications. The mean age at surgery was 29 years (range, 14-51 years). Postoperatively, the visual analog score decreased by an mean of 6 points (range, 1 to -10, P < 0.001), and patients were able to return to their preinjury Tegner activity level. When asked if they were satisfied by the overall outcome of their surgery, 28 patients (82%) were completely or mostly satisfied with their surgical outcome on a particular knee; 6 (18%) were somewhat satisfied; and 2 (6%) were dissatisfied. Twenty-seven patients (79%) said they would have the surgery again. CONCLUSION: The combined arthroscopic and open surgical technique described for chronic recalcitrant patellar tendinopathy successfully reduces knee pain and allows return to preinjury level of activity.

In-vivo glenohumeral translation and ligament elongation during abduction and abduction with internal and external rotation.

STUDY DESIGN: Basic Science. To investigate humeral head translations and glenohumeral ligament elongation with a dual fluoroscopic imaging system. BACKGROUND: The glenohumeral ligaments are partially responsible for restraining the humeral head during the extremes of shoulder motion. However, in-vivo glenohumeral ligaments elongation patterns have yet to be determined. Therefore, the objectives of this study were to 1) quantify the in-vivo humeral head translations and glenohumeral ligament elongations during functional shoulder positions, 2) compare the inferred glenohumeral ligament functions with previous literature and 3) create a baseline data of healthy adult shoulder glenohumeral ligament lengths as controls for future studies. METHODS: Five healthy adult shoulders were studied with a validated dual fluoroscopic imaging system (DFIS) and MR imaging technique. Humeral head translations and the superior, middle and inferior glenohumeral ligaments (SGHL, MGHL, IGHL) elongations were determined. RESULTS: The humeral head center on average translated in a range of 6.0mm in the anterior-posterior direction and 2.5mm in the superior-inferior direction. The MGHL showed greater elongation over a broader range of shoulder motion than the SGHL. The anterior-band (AB)-IGHL showed maximum elongation at 90° abduction with maximum external rotation. The posterior-band (PB)-IGHL showed maximum elongation at 90° abduction with maximum internal rotation. DISCUSSION: The results demonstrated that the humeral head translated statistically more in the anterior-posterior direction than the superior-inferior direction (p = 0.01), which supports the concept that glenohumeral kinematics are not ball-in-socket mechanics. The AB-IGHL elongation pattern makes it an important static structure to restrain anterior subluxation of the humeral head during the externally rotated cocking phase of throwing motion. These data suggest that in healthy adult shoulders the ligamentous structures of the glenohumeral joint are not fully elongated in many shoulder positions, but function as restraints at the extremes of glenohumeral motion. Clinically, these results may be helpful in restoring ligament anatomy during the treatment of anterior instability of the shoulder.

Effect of timing of ACL reconstruction in surgery and development of meniscal and chondral lesions.

PURPOSE: To investigate whether a delay in the timing of surgery of > 6 months compared with performing the surgery ≤ 6 months after the anterior cruciate ligament (ACL) injury leads to an increased risk of injuries or degenerative changes in the ACL-deficient knee. METHODS: Patients who underwent primary ACL reconstruction at an academic tertiary care center, and had preoperative magnetic resonance imaging (MRI) performed within 2 months of the time of the ACL injury were included. The prevalence of degenerative changes at the time of surgery was assessed and related to the timing of ACL surgery, with "early reconstruction" defined as a surgery performed ≤ 6 months and "delayed reconstruction" defined as surgery performed > 6 months after ACL injury. "New" meniscal tears were defined as lesions detected at the time of surgery that were not detected by MRI. RESULTS: Of 195 patients who were selected based on inclusion criteria, 171 patients underwent surgery ≤ 6 months after their ACL injury, and 24 patients underwent surgery > 6 months after their ACL injury. The prevalence of new medial meniscal tears in the early reconstruction group was 4.1%, while in the delayed reconstruction group, the prevalence was 16.7% (P = 0.012). CONCLUSION: A delay in the timing of ACL reconstruction from ≤ 6 months to > 6 months following injury is associated with a significant increase in the prevalence of medial meniscal tears (P = 0.012), with a relative risk of 4.07 (CI, 1.29-12.88).

Properties of cartilage engineered from elderly human chondrocytes for articular surface repair.

Numerous studies on engineering cartilage utilizing chondrocytes from juvenile animal sources have been reported. However, there are many unknown aspects of engineering cartilage using human chondrocytes-especially from middle-aged or elderly adults-which are critical for clinical application of tissue engineering in the field of orthopedic surgery. The primary aim of this study was to engineer neocartilage tissue from 50-60-year-old human chondrocytes in comparison to engineered cartilage made from juvenile swine chondrocytes (JSCs). Articular chondrocytes from middle-aged, nonarthritic humans and juvenile swine were isolated and placed in culture for expansion. The chondrocytes (passage 1) were mixed in fibrin gel at 40-60×10(6) cells/mL until polymerization. Cells/nodule constructs and devitalized cartilage-cells/hydrogel-devitalized cartilage constructs (three-layered model) were implanted into subcutaneous pockets of nude mice for 12, 18, and 24 weeks. The specimens were evaluated histologically, biochemically, and biomechanically. This allowed for direct comparison of the cartilage engineered from human versus swine cells. Histological analysis demonstrated that samples engineered utilizing chondrocytes from middle-aged adults accumulated basophilic, sulfated glycosaminoglycans (sGAG), and abundant type II collagen around the cells in a manner similar to that seen in samples engineered using JSCs at all time points. Biochemical analysis revealed that samples made with human cells had about 40%-60% of the amount hydroxyproline of native human cartilage, a trend parallel to that observed in the specimens made with swine chondrocytes. The amount of sGAG in the human chondrocyte specimens was about one-and-a-half times the amount in native human cartilage, whereas the amount in the samples made with swine chondrocytes was always less than native cartilage. The biomechanical analysis revealed that the stiffness and tensile of samples made with human cells were in a pattern similar to that seen with swine chondrocytes. This study demonstrates that chondrogenesis using articular chondrocytes from middle-aged adults can be achieved in a predictable and reliable manner similar to that shown in studies using cells from juvenile animals and can form the basis of engineering cartilage with degradable scaffolds in this patient population.