Emerging ideas: Novel 3-D quantification and classification of cam lesions in patients with femoroacetabular impingement.

BACKGROUND: Femoroacetabular impingement (FAI) can lead to labral injury, osseous changes, and even osteoarthritis. The literature contains inconsistent definitions of the alpha angle and other nonthree-dimensional (3-D) radiographic measures. We present a novel approach to quantifying cam lesions in 3-D terms. Our method also can be used to develop a classification system that describes the exact location and size of cam lesions. QUESTIONS/HYPOTHESES: We asked whether automated quantification of CAM lesions based on CT data is a reasonable way to detect CAM lesions and whether they may be classified based on location. METHOD OF STUDY: We developed a method to quantify femoral head cam lesions using 3-D modeling of CT scans. By segmenting raw DICOM data, we can determine the distance from the cam lesion's surface points to the centroid of the femoral head to quantify the mean bump height, volume, and location. The resulting 3-D femoral and acetabular models will be analyzed with custom software. We then will quantify the cam lesion with 3-D parameters using a modified zoning method. The mean bump height, volume, and location on the clock face, and relative zoning will be calculated. Zonal differences will be statistically analyzed. To assess the ability of this method to predict arthroscopic findings, we will obtain preoperative CT scans for 25 patients who undergo hip arthroscopy for FAI. We will compare measurements with the method with our measurements from arthroscopy. The clinical implications of our method's measurements then will be reviewed and refined for future prospective studies. SIGNIFICANCE: We present a novel approach that can quantify a cam lesion's location and size. This method will be used to provide guidelines for the exact amount of bony resection needed from a specific location of the proximal femur. There is also potential to develop software for ease of use so this method can be more widely applied.

Age-related differences in radiographic parameters for femoroacetabular impingement in hip arthroplasty patients.

PURPOSE: To compare the prevalence of femoroacetabular impingement (FAI) radiographic findings between patients aged younger than 50 years and those aged 50 years or older who underwent total hip arthroplasty. METHODS: Total hip arthroplasty patients aged younger than 50 years and those aged 50 years or older were identified retrospectively from a facility medical record database. Fifty patients from each group were randomly selected, and preoperative radiographs were collected. Dysplastic, inflammatory, post-traumatic, and osteonecrosis patients were excluded. Radiographs were evaluated for FAI-specific findings. Intraobserver and interobserver reliability was evaluated with κ statistics for categorical variables and intraclass correlation coefficients for continuous variables. An independent t test was used to compare continuous variables, χ(2) analysis was used for discrete variables, and a z ratio was used to analyze proportions. RESULTS: The mean age between the subgroups of patients aged younger than 50 years and those aged 50 years or older (43 years and 68 years, respectively) was significantly different (P < .05). Findings in the subgroup aged younger than 50 years included significantly more men (P < .001), decreased lateral joint space with maintained medial joint space (P < .05), significantly greater alpha angle on both the anteroposterior view and the frog-leg lateral view (P < .05), significantly higher Tönnis and Sharp angles (P < .01), and significantly lower center-edge angle (P < .001). CONCLUSIONS: This retrospective case series shows an increased prevalence of FAI findings (specifically cam pathology) in a patient population aged younger than 50 years undergoing total hip arthroplasty when compared with a cohort aged 50 years or older. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Complications associated with anterior shoulder instability repair.

Anterior shoulder instability is a common orthopaedic problem, and the surgical treatment, both open and arthroscopic, has been shown to effectively restore stability and prevent recurrence. However, despite success with these surgical techniques, there are several clinically relevant complications associated with both open and arthroscopic techniques for anterior shoulder stabilization. These complications can be subdivided into preoperative, intraoperative, and postoperative and include entities such as nerve injury, chondrolysis, incomplete treatment of associated lesions, and subscapularis dysfunction. When they occur, complications may significantly impact patient outcomes and function. Therefore, surgeon awareness and identification of the factors associated with these complications may help prevent occurrence. Although failure of instability repair can be classified as a complication of surgery, it requires an entirely separate discussion and is therefore not addressed in this article. Because most of the previously published studies on anterior shoulder instability have emphasized surgical technique and clinical outcomes, the purpose of this article is to define the complications associated with anterior instability repair and provide recommendations on techniques that may be used to help avoid them.

Triad of cartilage restoration for unicompartmental arthritis treatment in young patients: meniscus allograft transplantation, cartilage repair and osteotomy.

Arthritis treatment in young patients remains a challenge. Joint replacement surgery offers excellent pain relief but is controversial with this age group because of long-term wear and loosening. Recently, biological reconstructive techniques have become available to improve traditional treatment methods such as osteotomies. We present our experience with a technique for combined meniscal transplantation, chondral repair, and osteotomy in 7 patients presenting with a constellation of meniscal deficiency, focal arthritis, and malalignment. Patients underwent concurrent or staged meniscal transplantation, cartilage repair, and osteotomy. Evaluation included the International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Short Form-12 and Lysholm scales. At average follow-up of 24 months, patients experienced significant improvements in the IKDC, Lysholm, and KOOS functional scores. Six of 7 patients were able to return to unrestricted activities; 1 patient experienced mild pain with high-impact activities. Combined treatment with meniscal transplantation, cartilage repair, and osteotomy demonstrated promising clinical results of unicompartmental arthritis treatment in young patients.

Biceps tendinitis in chronic rotator cuff tears: a histologic perspective.

Patients with chronic rotator cuff tears frequently have anterior shoulder pain attributed to the long head of the biceps brachii (LHBB) tendon. In this study, tenodesis or tenotomy samples and cadaveric controls were assessed by use of immunohistochemical and histologic methods to quantify inflammation, vascularity, and neuronal plasticity. Patients had moderate pain and positive results on at least 1 clinical test of shoulder function. The number of axons in the distal LHBB was significantly less in patients with biceps tendinitis. Calcitonin gene-related peptide and substance P immunostaining was predominantly within nerve roots and blood vessels. A moderate correlation (R = 0.5) was identified between LHBB vascularity and pain scores. On the basis of these results, we conclude that, in the context of rotator cuff disease, the etiology of anterior shoulder pain with macroscopic changes in the biceps tendon is related to the complex interaction of the tendon and surrounding soft tissues, rather than a single entity.

Abnormal findings on knee magnetic resonance imaging in asymptomatic NBA players.

The purpose of this study was to evaluate the knees of asymptomatic National Basketball Association (NBA) players via magnetic resonance imaging (MRI) and confirm or dispute findings reported in the previous literature. It is thought that a variety of significant abnormalities affecting the knee exist in asymptomatic patients and that these findings can be accurately identified on MRI. Two months prior to the 2005 season, bilateral knee MRI examinations of 14 asymptomatic NBA players (28 knees) were evaluated for abnormalities of the articular cartilage, menisci, and patellar and quadriceps tendons. The presence of joint effusion, subchondral edema, and cystic lesions and the integrity of the collateral and cruciate ligaments were also assessed.

Outcomes of mechanical debridement and radiofrequency ablation in the treatment of chondral defects: a prospective randomized study.

This study compared the clinical and biomechanical outcomes of mechanical debridement with and without monopolar radiofrequency energy in treating chondral defects. Patients who were scheduled for arthroscopic procedures (diagnostic, debridement and lavage, and meniscectomy) and consented to biomechanical cartilage stiffness testing comprised the study population. Patients were randomized into 2 groups. In group 1, 14 patients underwent mechanical debridement only, and in group 2, 15 patients underwent mechanical debridement followed by monopolar radiofrequency. Clinical status was evaluated using the International Knee Documentation Committee (IKDC) subjective knee form. In group 2, the biomechanical properties of the defective cartilage before and after treatment also were evaluated. Findings showed a trend toward improvement in mechanical stiffness of energy-treated chondral lesions. Moreover, no significant differences were found between IKDC scores at average follow-up of 16 to 19 months. The addition of radiofrequency energy, at least in the investigated form, does not add clinically significant benefits over mechanical debridement alone of chondral defects.

Prospective evaluation of prolonged fresh osteochondral allograft transplantation of the femoral condyle: minimum 2-year follow-up.

BACKGROUND: Focal articular cartilage lesions of the knee in young patients present a therapeutic challenge. Little information is available pertaining to the results after implantation of prolonged fresh grafts. HYPOTHESIS: Prolonged fresh osteochondral allografts present a viable option for treating large full-thickness articular cartilage lesions. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: This study presents the results of 25 consecutive patients who underwent prolonged fresh osteochondral allograft transplantation for defects in the femoral condyle. The average patient age was 35 years (range, 17-49 years). The average length of follow-up was 35 months (range, 24-67 months). Prospective data were collected using several subjective scoring systems, as well as objective and radiographic assessments. RESULTS: Statistically significant improvements (P < .05) were seen for the Lysholm (39 to 67), International Knee Documentation Committee scores (29 to 58), all 5 components of the Knee injury and Osteoarthritis Outcome Score (Pain, 43 to 73; Other Disease-Specific Symptoms, 46 to 64; Activities of Daily Living Function, 56 to 83; Sport and Recreation Function, 18 to 46; Knee-Related Quality of Life, 22 to 50), and the Short Form-12 physical component score (36 to 40). Overall, patients reported 84% (range, 25% to 100%) satisfaction with their results and believed that the knee functioned at 79% (range, 35% to 100%) of their unaffected knee. Radiographically, 22 of the grafts (88%) were incorporated into host bone. CONCLUSION: Fresh osteochondral allograft transplantation is an acceptable intermediate procedure for treatment of localized osteochondral defects of the femur. At 2-year follow-up, it is well incorporated and offered consistent improvements in pain and function. CLINICAL RELEVANCE: Prolonged fresh allograft transplantation is a safe and effective technique for addressing symptomatic osteoarticular lesions in the knees of young patients.

Arthroscopic rotator cuff repair: prospective functional outcome and repair integrity at minimum 2-year follow-up.

The purpose of this study was to assess arthroscopic repair of rotator cuff tears at a minimum of 2 years postoperatively with both patient-derived and objective outcome measures, including the use of magnetic resonance imaging (MRI), to evaluate repair status. Evaluated were 49 shoulders in 47 consecutive patients. The American Shoulder and Elbow Surgeons score, Constant and Murley score, Simple Shoulder Test, Rowe score, Visual Analog Pain Scale, and the Medical Outcomes Study Short Form-12 Mental Component Scale all improved significantly (P < .001) between the preoperative and final follow-up evaluations. MRI found 22% of repairs had recurrent tears. The presence of a recurrent tear correlated significantly with patient age (P < .009) and extension of the tear to the infraspinatus (P < .009). Active forward flexion, abduction, external rotation, and strength in forward flexion correlated inversely with the presence of a recurrent tear (P < .05). At minimum 2-year follow-up, arthroscopic repair of rotator cuff tears produced significant improvements in both patient-derived and objectively measured variables.

Arthroscopic Anterior Cruciate Ligament Femoral Tunnel Visualization for Button Fixation.

Arthroscopic reconstruction of the anterior cruciate ligament (ACL) remains one of the most commonly performed procedures in orthopaedic surgery. We describe a technique to visualize the button being advanced through the femoral tunnel using an arthroscope placed in the anteromedial portal. Looking into the femoral tunnel in line with the sutures, this technique allows the surgeon to directly visualize the femoral button as it traverses the femoral tunnel and confirms that it is engaged over the femoral cortex. Certain complications can arise, however, with the use of a suspensory fixation with a button on the femoral cortex. This method can decrease operative time and complication rates.

Tibiofemoral contact mechanics after serial medial meniscectomies in the human cadaveric knee.

BACKGROUND: There is no consensus regarding the extent of meniscectomy leading to deleterious effects on tibiofemoral contact mechanics. HYPOTHESIS: The meniscus aids in optimizing tibiofemoral contact mechanics, increasing contact area, and decreasing contact stress. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve fresh-frozen human cadaveric knees each underwent 15 separate testing conditions-5 serial 20-mm posterior medial meniscectomy conditions (intact, 50% radial width, 75% radial width, segmental, and total meniscectomy) at 3 flexion angles (0 degrees , 30 degrees , and 60 degrees )-under an 1800-N axial load. Tekscan sensors were used to measure total force and medial force, contact area, mean contact stress, and peak contact stress. RESULTS: All posterior medial meniscectomy conditions resulted in significantly decreased contact areas and increased mean and peak contact stresses compared with the intact state (P < .05). The changes in contact mechanics after segmental and total posterior medial meniscectomies were not statistically different (P > .05). Incremental changes in contact area and mean contact stress increased as more peripheral portions of the medial meniscus were removed, whereas peak contact stresses exhibited similar incremental changes throughout all meniscectomy conditions. CONCLUSIONS: The meniscus is a crucial load-bearing structure, optimizing contact area and minimizing contact stress. Loss of hoop tension (ie, segmental meniscectomy) is equivalent to total meniscectomy in load-bearing terms. The peripheral portion of the medial meniscus provides a greater contribution to increasing contact areas and decreasing mean contact stresses than does the central portion, whereas peak contact stresses increase proportionally to the amount of meniscus removed. CLINICAL RELEVANCE: Because the degree of meniscectomy leading to clinically significant outcomes is unknown, a prudent strategy is to preserve the greatest amount of meniscus possible.

Chondrolysis after continuous intra-articular bupivacaine infusion: an experimental model investigating chondrotoxicity in the rabbit shoulder.

PURPOSE: Postoperative pain pumps are increasingly used to deliver a continuous infusion of local anesthetic into the surgical wound or the joint. Recently, there have been concerns that the use of such devices may be associated with chondrotoxicity and even cases of chondrolysis in the shoulder. An experimental model is presented that investigates potential chondrotoxic effects of a continuous intra-articular infusion of bupivacaine in the rabbit shoulder. METHODS: We divided 30 rabbits into 3 groups that received continuous infusions of either saline solution, bupivacaine, or bupivacaine with epinephrine into the glenohumeral joint over a period of 48 hours. Animals were killed after 1 week, and osteochondral and synovial samples from the glenohumeral joint underwent analyses with confocal microscopy for live/dead cell assay, metabolic sulfate uptake assessment, and conventional histologic analysis. RESULTS: Infusion of bupivacaine with epinephrine and without epinephrine decreased sulfate uptake by 56% (P = .009) and 50% (P = .02), respectively, when compared with saline solution; cell viability decreased by 20% (P = .08) and 32% (P = .02), respectively. Histologic analysis yielded significantly worse scores for bupivacaine infusion with epinephrine (P = .004) and without epinephrine (P = .02). The results for bupivacaine with or without epinephrine were not significantly different. CONCLUSIONS: Continuous intra-articular infusion of bupivacaine with and without epinephrine led to significant histopathologic and metabolic changes in articular cartilage. CLINICAL RELEVANCE: Bupivacaine showed profound chondrotoxic effects in an experimental model that closely followed the current clinical application of postoperative pain pumps. The results caution against the use of such devices in applications for smaller joints with minimal clearance or dilution as a result of hematoma, where continuous exposure of cartilage to bupivacaine is expected.

Basic science and treatment options for articular cartilage injuries.

Articular cartilage injuries can produce significant musculoskeletal morbidity for both young and active aging patient populations. The complex and highly specialized composition of normal hyaline cartilage makes treatment of focal chondral injuries a formidable challenge for the basic scientist, surgeon, and physical therapist. The current array of surgical treatment options offers palliative, reparative, and restorative treatment strategies. Palliative options include simple arthroscopic debridement. Reparative strategies utilize marrow stimulation techniques to induce formation of fibrocartilage within the chondral defect. Restorative tactics attempt to replace damaged cartilage with hyaline or hyaline-like tissue using osteochondral or chondrocyte transplantation. Furthermore, while treatment success is obviously dependent on good surgical selection and technique, the importance of sound, compliant postoperative rehabilitation cannot be understated. The purpose of this article is to review the basic science of articular cartilage, current treatment options available, and outline the clinical decision making involved when using these procedures by presenting the algorithm used at our institution for treating focal cartilage lesions.

Immortalized Mouse Achilles Tenocytes Demonstrate Long-Term Proliferative Capacity While Retaining Tenogenic Properties.

Investigating the cellular processes underlying tendon healing can allow researchers to improve long-term outcomes after injury. However, conducting meaningful studies to uncover the injury healing mechanism at cellular and molecular levels remains challenging. This is due to the inherent difficulty in isolating, culturing, and expanding sufficient primary tenocytes, due to their limited proliferative capacity and short lifespan. In this study, we sought to establish a novel line of immortalized mouse Achilles tenocytes (iMATs) with primary tenocyte properties, but increased proliferative capacity suitable for extensive in vitro experimentation. We show that isolated primary mouse Achilles tenocytes (pMATs) can be effectively immortalized using a piggyBac transposon expressing SV40 large T antigen flanked by FLP recombination target site (FRT). The resulting iMATs exhibit markedly greater proliferation and survival, which can be reversed with FLP recombinase. Furthermore, iMATs express the same set of tendon-specific markers as that of primary cells, although in lower levels, and respond similarly to exogenous stimulation with bone morphogenetic protein 13 (BMP13) as has been previously reported with pMATs. Taken together, our results suggest that iMATs acquire long-term proliferative capacity while maintaining tenogenic properties. We believe that iMATs are a suitable model for studying not only the native cellular processes involved in injury and healing, but also potential therapeutic agents that may augment the stability of tendon repair.

Rapid progression of chondral disease in the lateral compartment of the knee following meniscectomy.

We present 2 cases of severe, rapidly progressive chondral disease in the lateral compartment within 12 months after meniscectomy. In both cases, the lateral compartment was salvaged with simultaneously performed cartilage repair techniques and meniscal transplantation. The first case is of a 16-year-old boy who suffered a complex irreparable posterior horn lateral meniscus tear that was treated with an aggressive partial meniscectomy, and developed a rapid onset of severe lateral compartment symptoms associated with a focal grade IV chondral defect of the lateral femoral condyle within 10 months of his index meniscectomy. The second case is that of an athletic 43-year-old orthopaedic surgeon who suffered a complex lateral meniscus tear that required a near total lateral meniscectomy. Within 5 months of the lateral meniscectomy, he developed severe lateral symptoms with a focal grade IV chondral defect of the lateral femoral condyle. In both cases, the articular cartilage defects were treated with osteochondral grafting at the time of lateral meniscus transplantation with excellent results at 2-year follow-up. These cases highlight the significant need for a heightened the awareness of the relatively increased risk of rapid lateral compartment degeneration following lateral meniscectomy. This, in combination with the appropriate use of cartilage restoration techniques, provides the potential to salvage or prevent rapid onset, unicompartmental degenerative disease, and the ability to reduce symptoms and improve function in these challenging patients.

Pectoralis major repair with cortical button technique.

Pectoralis major tendon ruptures can lead to significant functional deficits that affect high-level athletic and labor-intensive activities. In active populations operative repair of the ruptured pectoralis major tendon has shown significant advantages over nonoperative treatment. We describe a novel surgical technique for pectoralis major repair with tension button fixation. This study included 12 recreational athletes and 2 professional athletes. The initial results were measured subjectively after a minimum of 6 months by the Single Assessment Numeric Evaluation score, the American Shoulder and Elbow Surgeons score, and the ability to return to the patient's sport at a preinjury level. Objectively, strength was measured with resisted horizontal adduction of the arm for both repaired and contralateral sides. Of the 12 recreational patients, 8 returned to their sport at preinjury levels, and the 2 professional athletes returned to their sport at full capacity in the National Football League. The mean Single Assessment Numeric Evaluation score was 87, and the mean American Shoulder and Elbow Surgeons scores were 99 for both the operative and contralateral sides. Isokinetic strength testing showed no significant differences between the operative and nonoperative sides. Patients with pectoralis major tendons repaired with the proposed tensioned cortical button technique had excellent results. This new technique provides a reliable method of repair in an efficient and safe manner.

Posterior instability caused by batter's shoulder.

In summary, batter's shoulder is a rare and only recently recognized entity. This condition is posterior shoulder instability caused by a missed attempt at hitting a pitch, especially with an outside pitch. The lack of counterforce from hitting a ball produces increased forces imparted on the posterior capsulolabral complex of the lead shoulder during batting. If the player fails conservative management, she or he can undergo an arthroscopic posterior labral repair instead of debridement. After treatment, the player can expect to return to play after approximately 6 to 7 months. Initial results from a small, retrospective series demonstrate greater than 90% excellent results. These findings are similar to current literature for arthroscopic treatment of posterior instability, which reports success rates that range from 75% to 91%. Longer-term follow-up will be needed to determine the natural history and prognosis or batter's shoulder. Based on initial results, the authors predict good to excellent results for most players with batter's shoulder who undergo proper treatment. Additionally, with the exception of switch hitters, the nonthrowing arm is affected. This can also improve the athlete's return to play.

The biomechanical effects of 1.0 to 1.2 Mrad of γ irradiation on human bone-patellar tendon-bone allografts.

BACKGROUND: Recent data suggest that anterior cruciate ligament (ACL) reconstruction with irradiated allograft tissue may lead to increased failure rates. HYPOTHESIS: Low-dose (1.0-1.2 Mrad) gamma irradiation does not significantly alter the preimplantation biomechanical properties of bone-patellar tendon-bone (BTB) allografts. STUDY DESIGN: Controlled laboratory study. METHODS: Cyclic and failure mechanical properties were evaluated for 20 paired central-third human BTB allografts, with and without 1.0 to 1.2 Mrad of gamma irradiation. Testing included cyclic loading at 0.5 Hz for 100 cycles from 50 to 200 N and failure testing at a strain rate of 10% per second. RESULTS: Cyclic elongation did not change significantly (P = .151) with irradiation, increasing from a mean ± SD of 9.4 ± 2.1 mm to 11.3 ± 3.4 mm. Cyclic creep strain approached a significant increase with irradiation (1.3% ± 0.8% to 2.6% ± 1.5%; P = .076). Failure testing was not affected with irradiation with regard to maximum load (1680 ± 417 mm to 1494 ± 435 mm), maximum stress (40.8 ± 10.6 MPa to 37.5 ± 15.7 MPa), elongation (7.85 ± 1.35 mm to 8.67 ± 2.05 mm), or strain at maximum stress (0.158 ± 0.03 to 0.175 ± 0.03). Graft stiffness significantly decreased by 20% with irradiation (278 ± 67 N/mm to 221 ± 50 N/mm; P = .035). CONCLUSION: Low-dose (1.0-1.2 Mrad) gamma irradiation decreases BTB graft stiffness by 20%, but it does not affect other failure or cyclic parameters. CLINICAL RELEVANCE: Aside from graft stiffness during load to failure testing, low-dose (1.0-1.2 Mrad) gamma irradiation of central-third human BTB allografts is not deleterious to preimplantation biomechanical properties.