Andreas H. Gomoll

Increased Failure Rate of Autologous Chondrocyte Implantation After Previous Treatment With Marrow Stimulation Techniques

Background Marrow stimulation techniques such as drilling or microfracture are first-line treatment options for symptomatic cartilage defects. Common knowledge holds that these treatments do not compromise subsequent cartilage repair procedures with autologous chondrocyte implantation. Hypothesis Cartilage defects pretreated with marrow stimulation techniques will have an increased failure rate. Study Design Cohort study; Level of evidence, 2. Methods The first 321 consecutive patients treated at one institution with autologous chondrocyte implantation for full-thickness cartilage defects that reached more than 2 years of follow-up were evaluated by prospectively collected data. Patients were grouped based on whether they had undergone prior treatment with a marrow stimulation technique. Outcomes were classified as complete failure if more than 25% of a grafted defect area had to be removed in later procedures because of persistent symptoms. Results There were 522 defects in 321 patients (325 joints) treated with autologous chondrocyte implantation. On average, there were 1.7 lesions per patient. Of these joints, 111 had previously undergone surgery that penetrated the subchondral bone; 214 joints had no prior treatment that affected the subchondral bone and served as controls. Within the marrow stimulation group, there were 29 (26%) failures, compared with 17 (8%) failures in the control group. Conclusion Defects that had prior treatment affecting the subchondral bone failed at a rate 3 times that of nontreated defects. The failure rates for drilling (28%), abrasion arthroplasty (27%), and microfracture (20%) were not significantly different, possibly because of the lower number of microfracture patients in this cohort (25 of 110 marrow-stimulation procedures). The data demonstrate that marrow stimulation techniques have a strong negative effect on subsequent cartilage repair with autologous chondrocyte implantation and therefore should be used judiciously in larger cartilage defects that could require future treatment with autologous chondrocyte implantation.

Repair and tissue engineering techniques for articular cartilage

Chondral and osteochondral lesions due to injury or other pathology commonly result in the development of osteoarthritis, eventually leading to progressive total joint destruction. Although current progress suggests that biologic agents can delay the advancement of deterioration, such drugs are incapable of promoting tissue restoration. The limited ability of articular cartilage to regenerate renders joint arthroplasty an unavoidable surgical intervention. This Review describes current, widely used clinical repair techniques for resurfacing articular cartilage defects; short-term and long-term clinical outcomes of these techniques are discussed. Also reviewed is a developmental pipeline of acellular and cellular regenerative products and techniques that could revolutionize joint care over the next decade by promoting the development of functional articular cartilage. Acellular products typically consist of collagen or hyaluronic-acid-based materials, whereas cellular techniques use either primary cells or stem cells, with or without scaffolds. Central to these efforts is the prominent role that tissue engineering has in translating biological technology into clinical products; therefore, concomitant regulatory processes are also discussed.

The subchondral bone in articular cartilage repair: current problems in the surgical management.

As the understanding of interactions between articular cartilage and subchondral bone continues to evolve, increased attention is being directed at treatment options for the entire osteochondral unit, rather than focusing on the articular surface only. It is becoming apparent that without support from an intact subchondral bed, any treatment of the surface chondral lesion is likely to fail. This article reviews issues affecting the entire osteochondral unit, such as subchondral changes after marrow-stimulation techniques and meniscectomy or large osteochondral defects created by prosthetic resurfacing techniques. Also discussed are surgical techniques designed to address these issues, including the use of osteochondral allografts, autologous bone grafting, next generation cell-based implants, as well as strategies after failed subchondral repair and problems specific to the ankle joint. Lastly, since this area remains in constant evolution, the requirements for prospective studies needed to evaluate these emerging technologies will be reviewed.

Biomechanical considerations in the pathogenesis of osteoarthritis of the knee

AbstractOsteoarthritis is the most common joint disease and a major cause of disability. The knee is the large joint most affected. While chronological age is the single most important risk factor of osteoarthritis, the pathogenesis of knee osteoarthritis in the young patient is predominantly related to an unfavorable biomechanical environment at the joint. This results in mechanical demand that exceeds the ability of a joint to repair and maintain itself, predisposing the articular cartilage to premature degeneration. This review examines the available basic science, preclinical and clinical evidence regarding several such unfavorable biomechanical conditions about the knee: malalignment, loss of meniscal tissue, cartilage defects and joint instability or laxity. Level of evidence IV.

Repair of Large Chondral Defects of the Knee with Autologous Chondrocyte Implantation in Patients 45 Years or Older

Background Autologous chondrocyte implantation (ACI) has become an accepted option for the treatment of chondral defects in carefully selected patients. Current recommendations limit this procedure to younger patients, as insufficient data are available to conclusively evaluate outcomes in patients older than 45 years. Hypothesis Cartilage repair with ACI in patients older than 45 years results in substantially different outcomes than those previously reported for younger age groups. Study Design Case series; Level of evidence, 4. Methods This prospective cohort study reviewed patients 45 years of age at the time of treatment with ACI. The clinical evaluation included a patient satisfaction questionnaire and four validated rating scales: Short Form-36, Modified Cincinnati Rating Scale, WOMAC (Western Ontario and McMaster Universities) Osteoarthritis Index, and the Knee Society Score. Results A total of 56 patients 45 years of age were treated with ACI. The average patient age at index surgery was 48.6 years (range, 45–60 years). The minimum follow-up was 2 years (range, 2–11 years; mean, 4.7 years). The cohort included 36 men and 20 women. The mean transplant size was 4.7 cm2 per defect (range, 1–15.0 cm2) and 9.8 cm2 per knee (range, 2.5–31.6 cm2). Twenty-eight patients (50%) underwent concomitant osteotomies to address malalignment. There were 8 failures (14%); 6 of 15 (40%) in patients receiving workers’ compensation (WC) and 2 of 41 (4.9%) in non-WC patients. Additional arthroscopic surgical procedures were required in 24 patients (43%) for periosteal-related problems and adhesions; 88% of these patients experienced lasting improvement. At their latest available follow-up, 72% of patients rated themselves as good or excellent, 78% felt improved, and 81 % would again choose ACI as a treatment option. Conclusion Our results showed a failure rate of ACI in older patients that is comparable with rates reported in younger patient groups. The procedure is associated with a substantial rate of reoperations, mostly for the arthroscopic treatment of graft hypertrophy, similar to that in younger patients.

Use of a Type I/III Bilayer Collagen Membrane Decreases Reoperation Rates for Symptomatic Hypertrophy After Autologous Chondrocyte Implantation

Background Autologous chondrocyte implantation is associated with a high rate of reoperation, mostly due to hypertrophy of the periosteal patch. European studies investigating the use of collagen membranes as a periosteal substitute report significant decreases in reoperation rates to less than 5%. This multicenter study investigates the off-label use of 1 collagen membrane as a periosteal substitute for autologous chondrocyte implantation. Hypothesis The use of a collagen membrane for autologous chondrocyte implantation will decrease reoperation rates for hypertrophy with comparable rates of failure. Study Design Cohort study; Level of evidence, 3. Methods A multicenter cohort of 300 patients treated with periosteal-covered autologous chondrocyte implantation was compared with a consecutive series of 101 patients who underwent collagen membrane–covered autologous chondrocyte implantation with the Bio-Gide membrane by the same group of surgeons. The 1-year hypertrophy-related reoperation rates and overall failure rates of autologous chondrocyte implantation were evaluated in both groups. Results Both groups were comparable for age (periosteal autologous chondrocyte implantation, 31.9 years; collagen autologous chondrocyte implantation, 32.4 years; P 5 .8) and average defect size (4.6 cm2 and 4.7 cm2, respectively; P 5 .7). The average number of defects (1.5 and 1.8; P 5 .001) and total defect area per knee (6.7 cm2 and 8.6 cm2; P 5 .003) were larger in the collagen membrane group. Within 1 year of surgery, 25.7% of patients treated with periosteal-covered autologous chondrocyte implantation required reoperation for hypertrophy and 2.3% were considered to have failed their treatment with autologous chon-drocyte implantation. In comparison, only 5% of patients required reoperation for hypertrophy after collagen membrane–covered autologous chondrocyte implantation, and 4% were considered treatment failures. Conclusion The use of a collagen membrane for autologous chondrocyte implantation decreased the reoperation rate for hypertrophy after autologous chondrocyte implantation from 25.7% to 5% (P < .0001). Overall 1-year failure rates were comparable between the groups (P 5 .2). Even though the use of a collagen membrane for autologous chondrocyte implantation constitutes an off-label indication, its application appears justified by the lower morbidity to patients and decreased cost to the health care system. A detailed discussion with the patient is required regarding the use of an off-label device.

Long-Term Effects of Bupivacaine on Cartilage in a Rabbit Shoulder Model

Background Previous investigations have reported on the chondrotoxicity of bupivacaine in short-term in vivo and in vitro models. This study was designed to provide additional information on the long-term effects of bupivacaine infusion on articular cartilage in an established rabbit shoulder model. Hypothesis Infusion of bupivacaine into the rabbit shoulder will have long-term deleterious effects on articular cartilage. Study Design Controlled laboratory study. Methods Thirty-six rabbits were randomized into 3 groups and were infused over 48 hours with saline (S), bupivacaine alone (B), or bupivacaine with epinephrine (B+E) into the glenohumeral joint. Animals were sacrificed after 3 months, and tissue samples were analyzed with live/dead cell assay, proteoglycan (PG) synthesis and content assays, and conventional histological evaluation. Results No macroscopic or radiographic changes were detected in the infused shoulders. Sulfate uptake of infused shoulders relative to controls was elevated to 112% ± 39% (S), 166% ± 67% (B), and 210% ± 127% (B+E). Statistical analysis of PG content demonstrated significantly increased levels in bupivacaine groups compared with saline. There were no significant differences among groups in cell count, percentage of living cells, or histological grade. Conclusions No permanent impairment of cartilage function was detected 3 months after intra-articular infusion of bupivacaine. Cartilage metabolism was increased, indicating a possible reparative response. This suggests that, at least in the model used, articular cartilage has the ability to recover from the chondrotoxic effects of bupivacaine infusion. Before extrapolating these results to human cartilage, other factors including underlying cartilage injury or disease, decreased chondrocyte density, and increased bupivacaine dosing need to be taken into account. Clinical Relevance Bupivacaine toxicity has recently been implicated in the development of chondrolysis after arthroscopic shoulder procedures, but these findings suggest that additional noxious stimuli might be required before permanent damage ensues.

Surgical treatment for early osteoarthritis. Part I: cartilage repair procedures.

AbstractYoung patients with early osteoarthritis (OA) represent a challenging population due to a combination of high functional demands and limited treatment options. Conservative measures such as injection and physical therapy can provide short-term pain relief but are only palliative in nature. Joint replacement, a successful procedure in the older population, is controversial in younger patients, who are less satisfied and experience higher failure rates. Therefore, while traditionally not indicated for the treatment of OA, cartilage repair has become a focus of increased interest due to its potential to provide pain relief and alter the progression of degenerative disease, with the hope of delaying or obviating the need for joint replacement. This review of cartilage repair techniques will discuss currently available procedures, specifically pertaining to experiences in the setting of early OA. Level of evidence IV.

Surgical Experience Correlates With Performance on a Virtual Reality Simulator for Shoulder Arthroscopy

Background The traditional process of surgical education is being increasingly challenged by economic constraints and concerns about patient safety. Sophisticated computer-based devices have become available to simulate the surgical experience in a protected environment. As with any new educational tool, these devices have generated controversy about the validity of the training experience. Hypothesis Performance on a virtual reality simulator correlates with actual surgical experience. Study Design Controlled laboratory study. Methods Forty-three test subjects of various experience levels in shoulder arthroscopy were tested on an arthroscopy simulator according to a standardized protocol. Subjects were evaluated for time to completion, distance traveled with the tip of the simulated probe compared with a computer-determined optimal distance, average probe velocity, and number of probe collisions with the tissues. Results Subjects were grouped according to prior experience with shoulder arthroscopy. Comparing the least experienced with most experienced groups, the average time to completion decreased by 62% from 128.8 seconds to 49.2 seconds; path length and hook collisions were more than halved from 8.2 to 3.8 and 34.1 to 16.8, respectively; and average probe velocity more than doubled from 0.18 to 0.4 cm/second. There were no significant differences for any parameter tested between subjects with video game experience compared to those without. Conclusions The study demonstrated a close and statistically significant correlation between simulator results and surgical experience, thus confirming the hypothesis. Conversely, experience with video games was not associated with improved simulator performance. This indicates that the skill set tested may be similar to the one developed in the operating room, thus suggesting its use as a potential tool for future evaluation of surgical trainees. Clinical Relevance The results have implications for the future of orthopaedic surgical training programs, the majority of which have not embraced virtual reality technology for physician education.

Individual Skill Progression on a Virtual Reality Simulator for Shoulder Arthroscopy: A 3-Year Follow-up Study

Background Previous studies have demonstrated a correlation between surgical experience and performance on a virtual reality arthroscopy simulator but only provided single time point evaluations. Additional longitudinal studies are necessary to confirm the validity of virtual reality simulation before these teaching aids can be more fully recommended for surgical education. Hypothesis Subjects will show improved performance on simulator retesting several years after an initial baseline evaluation, commensurate with their advanced surgical experience. Study Design Controlled laboratory study. Methods After gaining further arthroscopic experience, 10 orthopaedic residents underwent retesting 3 years after initial evaluation on a Procedicus virtual reality arthroscopy simulator. Using a paired t test, simulator parameters were compared in each subject before and after additional arthroscopic experience. Subjects were evaluated for time to completion, number of probe collisions with the tissues, average probe velocity, and distance traveled with the tip of the simulated probe compared to an optimal computer-determined distance. In addition, to evaluate consistency of simulator performance, results were compared to historical controls of equal experience. Results Subjects improved significantly (P < .02 for all) in the 4 simulator parameters: completion time (−51 %), probe collisions (−29%), average velocity (+122%), and distance traveled (−;32%). With the exception of probe velocity, there were no significant differences between the performance of this group and that of a historical group with equal experience, indicating that groups with similar arthroscopic experience consistently demonstrate equivalent scores on the simulator. Conclusion Subjects significantly improved their performance on simulator retesting 3 years after initial evaluation. Additionally, across independent groups with equivalent surgical experience, similar performance can be expected on simulator parameters; thus it may eventually be possible to establish simulator benchmarks to indicate likely arthroscopic skill. Clinical Relevance These results further validate the use of surgical simulation as an important tool for the evaluation of surgical skills.