Robert A. Siston

Autologous Chondrocyte Implantation: A Systematic Review

BACKGROUND The purpose of the present study was to determine (1) whether the current literature supports the choice of using autologous chondrocyte implantation over other cartilage procedures with regard to clinical outcome, magnetic resonance imaging, arthroscopic assessment, and durability of treatment, (2) whether the current literature supports the use of a specific generation of autologous chondrocyte implantation, and (3) whether there are patient-specific and defect-specific factors that influence outcomes after autologous chondrocyte implantation in comparison with other cartilage repair or restoration procedures. METHODS We conducted a systematic review of multiple databases in which we evaluated Level-I and II studies comparing autologous chondrocyte implantation with another cartilage repair or restoration technique as well as comparative intergenerational studies of autologous chondrocyte implantation. The methodological quality of studies was evaluated with use of Delphi list and modified Coleman methodology scores. Effect size analysis was performed for all outcome measures. RESULTS Thirteen studies (917 subjects) were included. Study methodological quality improved with later publication dates. The mean modified Coleman methodology score was 54 (of 100). Patients underwent autologous chondrocyte implantation (n = 604), microfracture (n = 271), or osteochondral autograft (n = 42). All surgical techniques demonstrated improvement in comparison with the preoperative status. Three of seven studies showed better clinical outcomes after autologous chondrocyte implantation in comparison with microfracture after one to three years of follow-up, whereas one study showed better outcomes two years after microfracture and three other studies showed no difference in these treatments after one to five years. Clinical outcomes after microfracture deteriorated after eighteen to twenty-four months (in three of seven studies). Autologous chondrocyte implantation and osteochondral autograft demonstrated equivalent short-term clinical outcomes, although there was more rapid improvement after osteochondral autograft (two studies). Although outcomes were equivalent between first and second-generation autologous chondrocyte implantation and between open and arthroscopic autologous chondrocyte implantation, complication rates were higher with open, periosteal-cover, first-generation autologous chondrocyte implantation (four studies). Younger patients with a shorter preoperative duration of symptoms and fewer prior surgical procedures had the best outcomes after both autologous chondrocyte implantation and microfracture. A defect size of >4 cm(2) was the only factor predictive of better outcomes when autologous chondrocyte implantation was compared with a non-autologous chondrocyte implantation surgical technique. CONCLUSIONS Cartilage repair or restoration in the knee provides short-term success with microfracture, autologous chondrocyte implantation, or osteochondral autograft. There are patient-specific and defect-specific factors that influence clinical outcomes.

The variability of femoral rotational alignment in total knee arthroplasty

BACKGROUND Several reference axes are used to establish femoral rotational alignment during total knee arthroplasty, but debate continues with regard to which axis is most accurately and easily identified during surgery. Computer-assisted navigation systems have been developed in an attempt to more accurately and consistently align implants during total knee arthroplasty, but it is unknown if navigation systems can improve the accuracy of femoral rotational alignment as compared with that achieved with more traditional techniques involving mechanical guides. The purposes of the present study were to characterize the variability associated with femoral rotational alignment techniques and to determine whether the use of a computer-assisted surgical navigation system reduced this variability. METHODS Eleven orthopaedic surgeons used five alignment techniques (including one computer-assisted technique and four traditional techniques) to establish femoral rotational alignment axes on ten cadaveric specimens, and the orientation of these axes was recorded with use of a navigation system. These derived axes were compared against a reference transepicondylar axis on each femur that was established after complete dissection of all soft tissues. RESULTS There was no difference between the mean errors of all five techniques (p > 0.11). Only 17% of the knees were rotated <5 degrees from the reference transepicondylar axis, with alignment errors ranging from 13 degrees of internal rotation to 16 degrees of external rotation. There were significant differences among the surgeons with regard to their ability to accurately establish femoral rotational alignment axes (p < 0.001). CONCLUSIONS All techniques resulted in highly variable rotational alignment, with no technique being superior. This variability was primarily due to the particular surgeon who was performing the alignment procedure. A navigation system that relies on directly digitizing the femoral epicondyles to establish an alignment axis did not provide a more reliable means of establishing femoral rotational alignment than traditional techniques did.

Prevalence of chondral defects in athletes' knees: a systematic review.

PURPOSE To determine the prevalence of full-thickness focal chondral defects in the athletes knee. METHODS We conducted a systematic review of multiple databases, evaluating studies of the prevalence of articular cartilage defects in athletes. Because of the heterogeneity of data, a meta-analysis could not be performed. RESULTS Eleven studies were identified for inclusion (931 subjects). All studies were level 4 evidence. Defects were diagnosed via magnetic resonance imaging, arthroscopy, or both. Forty percent of athletes were professionals (NBA and NFL). The overall prevalence of full-thickness focal chondral defects in athletes was 36% (range = 2.4%-75% between all studies). Fourteen percent of athletes were asymptomatic at the time of diagnosis. Patellofemoral defects (37%) were more common than femoral condyle (35%) and tibial plateau defects (25%). Medial condyle defects were more common than lateral (68% vs 32%), and patella defects were more common than trochlea (64% vs 36%). Meniscal tear (47%) was the most common concomitant knee pathological finding, followed by anterior cruciate ligament tear (30%) and then medial collateral ligament or lateral collateral ligament tear (14%). CONCLUSIONS Full-thickness focal chondral defects in the knee are more common in athletes than among the general population. More than one-half of asymptomatic athletes have a full-thickness defect. Further study is needed to define more precisely the prevalence of these lesions in this population.

Failures, re-operations, and complications after autologous chondrocyte implantation – a systematic review

OBJECTIVE To determine and compare failure, re-operation, and complication rates of all generations and techniques of autologous chondrocyte implantation (ACI). METHODS A systematic review of multiple medical databases was performed according to PRISMA guidelines. Levels I-IV evidence were included. Generations of ACI and complications after ACI were explicitly defined. All subject and defect demographic data were analyzed. Modified Coleman Methodology Scores (MCMSs) were calculated for all studies. RESULTS 82 studies were identified for inclusion (5276 subjects were analyzed; 6080 defects). Ninety percent of the studies in this review were rated poor according to the MCMS. There were 305 failures overall (5.8% subjects; mean time to failure 22 months). Failure rate was highest with periosteal ACI (PACI). Failure rates after PACI, collagen-membrane cover ACI (CACI), second generation, and all-arthroscopic, second-generation ACI were 7.7%, 1.5%, 3.3%, and 0.83%, respectively. The failure rate of arthrotomy-based ACI was 6.1% vs 0.83% for all-arthroscopic ACI. Overall rate of re-operation was 33%. Re-operation rate after PACI, CACI, and second-generation ACI was 36%, 40%, and 18%, respectively. However, upon exclusion of planned second-look arthroscopy, re-operation rate was highest after PACI. Unplanned re-operation rates after PACI, CACI, second-generation, and all-arthroscopic second-generation ACI were 27%, 5%, 5%, and 1.4%, respectively. Low numbers of patients undergoing third-generation ACI precluded comparative analysis of this group. CONCLUSIONS Failure rate after all ACI generations is low (1.5-7.7%). Failure rate is highest with PACI, and lower with CACI and second-generation techniques. One out of three ACI patients underwent a re-operation. Unplanned re-operations are seen most often following PACI. Hypertrophy and delamination is most commonly seen after PACI. Arthrofibrosis is most commonly seen after arthrotomy-based ACI. Use of a collagen-membrane cover, second-generation techniques, and all-arthroscopic, second-generation approaches have reduced the failure, complication, and re-operation rate after ACI.

Results of an Initial Experience with Custom-fit Positioning Total Knee Arthroplasty in a Series of 48 Patients

The custom-fit approach to total knee arthroplasty in conjunction with removal of osteophytes and preservation of ligaments rapidly returned function; restored motion, stability, and postoperative mechanical axis alignment; effected high patient satisfaction; and had an acceptable clinical outcome.

Treatment of Chondral Defects in the Athlete's Knee

PURPOSE To determine which surgical technique(s) has improved outcomes and enables athletes to return to their preinjury level of sports and which patient and defect factors significantly affect outcomes after cartilage repair or restoration. METHODS We conducted a search of multiple medical databases, evaluating studies of articular cartilage repair in athletes. RESULTS We identified 11 studies for inclusion (658 subjects). Only 1 randomized clinical trial was identified. All other studies were prospective cohorts, case-control studies, or case series reporting results after either microfracture or autologous chondrocyte implantation (ACI) or osteoarticular transplantation (OATS). Eight different clinical outcomes measures were used. Better clinical outcomes were observed after ACI and OATS versus microfracture. Results after microfracture tended to deteriorate with time. The overall rate of return to preinjury level of sports was 66%. The timing of return to the preinjury level of sports was fastest after OATS and slowest after ACI. Defect size of less than 2 cm(2), preoperative duration of symptoms of less than 18 months, no prior surgical treatment, younger patient age, and higher preinjury and postsurgical level of sports all correlated with improved outcomes after cartilage repair, especially ACI. Results after microfracture were worse with larger defects. The rate of return to sports was generally lower after microfracture versus ACI or OATS, and if a patient was able to return to sports, performance was diminished as well. CONCLUSIONS Management of chondral defects in the athlete is complex and multifactorial. There is little high-level evidence to support one procedure over another, although good short-term and midterm outcomes with a fair rate of return to preinjury level of sports can be achieved with cartilage repair and restoration in the athlete. LEVEL OF EVIDENCE Level IV, systematic review.

How to write a systematic review

Background: The role of evidence-based medicine in sports medicine and orthopaedic surgery is rapidly growing. Systematic reviews and meta-analyses are also proliferating in the medical literature. Purpose: To provide the outline necessary for a practitioner to properly understand and/or conduct a systematic review for publication in a sports medicine journal. Study Design: Review. Methods: The steps of a successful systematic review include the following: identification of an unanswered answerable question; explicit definitions of the investigation’s participant(s), intervention(s), comparison(s), and outcome(s); utilization of PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines and PROSPERO registration; thorough systematic data extraction; and appropriate grading of the evidence and strength of the recommendations. Results: An outline to understand and conduct a systematic review is provided, and the difference between meta-analyses and systematic reviews is described. The steps necessary to perform a systematic review are fully explained, including the study purpose, search methodology, data extraction, reporting of results, identification of bias, and reporting of the study’s main findings. Conclusion: Systematic reviews or meta-analyses critically appraise and formally synthesize the best existing evidence to provide a statement of conclusion that answers specific clinical questions. Readers and reviewers, however, must recognize that the quality and strength of recommendations in a review are only as strong as the quality of studies that it analyzes. Thus, great care must be used in the interpretation of bias and extrapolation of the review’s findings to translation to clinical practice. Without advanced education on the topic, the reader may follow the steps discussed herein to perform a systematic review.

The High Variability of Tibial Rotational Alignment in Total Knee Arthroplasty

Although various techniques are advocated to establish tibial rotational alignment during total knee arthroplasty, it is unknown which is most repeatable. We evaluated the precision and accuracy of five tibial rotational alignment techniques to determine whether computer-assisted navigation systems can reduce variability of tibial component rotational alignment when compared to traditional instrumentation. Eleven orthopaedic surgeons used four computer-assisted techniques that required identification of anatomical landmarks and one that used traditional extramedullary instrumentation to establish tibial rotational alignment axes on 10 cadaver legs. Two computer-assisted techniques (axes between the most medial and lateral border of the tibial plateau, and between the posterior cruciate ligament [PCL] and the anterior tibial crest) and the traditional technique were least variable, with standard deviations of 9.9°, 10.8°, and 12.1°, respectively. Computer-assisted techniques referencing the tibial tubercle (axes between the PCL and the medial border or medial ⅓ of the tubercle) were most variable, with standard deviations of 27.4° and 28.1°. The axis between the medial border of the tibial tubercle and the PCL was internally rotated compared to the other techniques. None of the techniques consistently established tibial rotational alignment, and navigation systems that establish rotational alignment by identifying anatomic landmarks were not more reliable than traditional instrumentation. Level of Evidence: Level I, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Biomechanical effects of total knee arthroplasty component malrotation: a computational simulation.

Modern total knee arthroplasty (TKA) is an effective procedure to treat pain and disability due to osteoarthritis, but some patients experience quadriceps weakness after surgery and have difficulty performing important activities of daily living. The success of TKA depends on many factors, but malalignment of the prosthetic components is a major cause of postoperative complications. Significant variability is associated with femoral and tibial component rotational alignment, but how this variability translates into functional outcome remains unknown. We used a forward‐dynamic computer model of a simulated squatting motion to perform a parametric study of the effects of variations in component rotational alignment in TKA. A cruciate‐retaining and posterior‐stabilized version of the same TKA implant were compared. We found that femoral rotation had a greater effect on quadriceps forces, collateral ligament forces, and varus/valgus kinematics, while tibial rotation had a greater effect on anteroposterior translations. Our findings support the tendency for orthopedic surgeons to bias the femoral component into external rotation and avoid malrotation of the tibial component.

Biological knee reconstruction: a systematic review of combined meniscal allograft transplantation and cartilage repair or restoration.

PURPOSE Combined meniscal allograft transplantation (MAT) and cartilage repair or restoration is a recognized treatment for patients with painful, meniscus-deficient knees and full-thickness cartilage damage. The purpose of this systematic review was to compare outcomes after combined MAT and cartilage repair/restoration with the outcomes of isolated MAT or cartilage repair/restoration. METHODS Multiple databases were searched with specific inclusion and exclusion criteria for clinical outcome studies after combined MAT and cartilage repair or restoration. RESULTS Six studies were identified for inclusion. In total 110 patients underwent combined MAT/cartilage repair or restoration (medial compartment in 66 and lateral compartment in 44). Patients underwent MAT and either autologous chondrocyte implantation (n = 73), osteochondral allograft (n = 20), osteochondral autograft transfer (n = 17), or microfracture (n = 3). Thirty-six patients underwent additional concurrent surgeries (high tibial or distal femoral osteotomy, cruciate or collateral ligament reconstruction, and hardware removal). All clinical outcomes were improved at final follow-up (mean, 36 months). In 4 of 6 studies, overall outcomes of combined surgery were equivalent to those of either procedure performed in isolation. In 2 studies outcomes of combined surgery were not as good as those of either procedure performed in isolation. Failure occurred in 12% of patients who underwent combined MAT and cartilage restoration, and they required revision surgery. Most failures (85%) of combined surgery were due to failure of the MAT (as opposed to the cartilage technique). One-half of all patients required at least 1 surgery after the index procedure before final follow-up. CONCLUSIONS Clinical outcomes after combined MAT and cartilage repair/restoration are similar to those after either procedure in isolation. Despite low rates of complications and failures, there is a high rate of subsequent surgery after combined MAT and cartilage repair or restoration. LEVEL OF EVIDENCE Level IV, systematic review of Level IV studies.