The management of early OA in young patients with joint preservation techniques utilizing cartilage repair remains challenging and a suitable treatment remains unclear. The management of bipolar chondral lesions in the patello-femoral (PF) and in the tibio-femoral (TF) compartment with cartilage repair is especially troublesome. The purpose of this study was to evaluate the clinical outcomes and survivorship after ACI for the treatment of bipolar chondral lesions in the PF and TF compartment. This was an IRB approved, prospectively collected case series, level 4 study. We evaluated 115 patients. 58 patients who had ACI for the treatment of symptomatic bipolar chondral lesions in the PF compartment and 57 in the TF compartment with a minimum 2-year follow up. A single surgeon performed all the surgeries between October 1995 and June 2014. In the PF group, all 58 patients (60 knees; mean age, 36.6 years) were included, and for the TF group one patient did not return for follow-up, 56 patients (58 knees) were included. For the PF group, an average size of the patella and trochlea lesions were 5.6 ± 2.7 cm2 and 4.2 ± 2.8 cm2, respectively. For the TF group, an average of 3.1 lesions per knee were treated, representing a total surface area of 16.1 cm2 (range, 3.2 – 44.5 cm2) per knee. Patients were evaluated with the modified Cincinnati Knee Rating Scale, Visual Analogue Scale, Western Ontario and McMaster Universities Osteoarthritis Index, and the Short Form 36. Patients also answered questions regarding self-rated knee function and satisfaction with the procedure. Standard radiographs were evaluated for progression of OA.Introduction
Methods
Historical studies in TKA suggest that 82–89% of patients are satisfied with TKA. Bourne et al. reviewed 1703 patients and reported that in newer designs that things have not improved much. Approximately one in five (19%) primary TKA patients were not satisfied with the outcome. Satisfaction with pain relief varied from 72–86% and with function from 70–84% for specific activities of daily living. The burden of OA is increasing in society and younger patients are undergoing TKA. A customised, individually made (CIM) knee arthroplasty (iTotal, ConforMIS Inc., Bedford, MA USA) has been introduced by individualising component geometry; exact sizing- medial – lateral and anterior–posterior, restoring medial and lateral joint lines, and restoring individual “J Curves” of the patients’ native femur as it was prior to the arthritic condition. This is done by preoperative CT scanning to include hip-knee-ankle and software to CAD-CAM manufacture of the individualised implants, with accompanying individualised cutting jigs. The hypothesis is to restore form and ultimately function. Will this lead to improved patient satisfaction? Cadaveric comparison on an “Off The Shelf ” (OTS) implant to CIM implant in 9 matched pair analyses before and after TKA demonstrated that the CIM implant motion was not different than their preoperative kinematics of the knee but the OTS implant was. In vivo comparisons performed fluoroscopically of CIM implants versus OTS implants further demonstrated a more normal knee in terms of kinematics and stability in the CIM knee. Follow up of 110 consecutive patients undergoing a CIM CR TKA revealed patient satisfaction of 98%. Patient average age was 56.1 years old, average follow up 20 months. Two patients required revision- (both dissatisfied)- one for tibial subsidence 18 months after TKA (osteoporosis and obesity) the other developed global laxity at 9 months postoperatively. Both revised with stabilised PS OTS implants. At this early average follow up of <2 years it appears that patient satisfaction improves over prior OTS implant satisfaction with a CIM TKA that restores native size and geometry.
Cartilage is known to have limited intrinsic repair capabilities and cartilage defects can progress to osteoarthritis (OA). OA is a major economic burden of the 21st century, being among the leading causes of disability. The risk of disability from knee OA is as great as that derived from cardiovascular disease; a fact that becomes even more concerning when considering that even isolated cartilage defects can cause pain and disability comparable to that of severe OA. Several cartilage repair procedures are in current clinical application, including microfracture, osteochondral autograft transfer, osteochondral allograft transplantation, and autologous chondrocyte implantation (ACI). Given the economic challenges facing our health care system, it appears prudent to choose procedures that provide the most durable long-term outcome. Comparatively few studies have examined long-term outcomes, an important factor when considering the substantial differences in cost and morbidity among the various treatment options. This study reviews the clinical outcomes of autologous chondrocyte implantation at a minimum of 10 years after treatment of chondral defects of the knee. Mean age at surgery was 36 ± 9 years; mean defect size measured 8.4 ± 5.5cm2. Outcome scores were prospectively collected pre- and postoperatively at the last follow up. We further analyzed potential factors contributing to failure in hopes of refining the indications for this procedure. Conclusions: ACI provided durable outcomes with a survivorship of 71% at 10 years and improved function in 75% of patients with symptomatic cartilage defects of the knee at a minimum of 10 years after surgery. A history of prior marrow stimulation as well as the treatment of very large defects was associated with an increased risk of failure.
Although cartilage repair has been around since the time of open Pridie drilling, clinical outcomes for newer techniques such as arthroscopic debridement, microfracture (MFX), osteochondral autograft transfers (OATS), osteochondral allograft transplantation and Autologous Chondrocyte Implantation (ACI) are still finding their place in treating injured knees. Early mechanical symptoms are best managed by a gentle arthroscopic debridement of loose articular flaps. This allows the surgeon to assess the defect size, location in the tibio-femoral or patellofemoral joint, status of the cartilage overall and patients response to the intervention. If the symptom improvement is not satisfactory to the patient, after assessing background factors that will influence the results of a cartilage repair procedure, (alignment of the patellofemoral joint or axial alignment, ligament stability and status of the meniscus), the surgeon can choose the best procedure for that individual based on the expected outcomes of the various cartilage repair techniques while addressing the background factors. As all the techniques have failures and informed discussion with the patient prior to performing the procedure is critical in avoiding disappointment for the patient and the surgeon. The repair technique used should incorporate considerations of the defect size, location, and the patient age, activity level, expectations and ability to comply with the longer rehabilitation needed for biological procedures as compared to prosthetic implants.
Up until this point in time, total knee replacement implants have relied on standardised sizes and shapes. The design process for the ‘off-the-shelf’ implants has typically involved designing a standard size implant and then scaling the design up and down to provide a series of standard sizes. More recently, some suppliers have paid more attention to providing sizes that meet the particular needs for either women or men, but these implants are largely standard designs with adjustments to the medial to lateral width or the anterior to posterior depth. To design an implant that not only provides the correct size for every patient's knee, but more importantly to provide an implant that duplicated the patient's exact geometry is the goal. A CT scan is obtained of the patient's lower limb. The CT data is converted into a surface model of the knee joint with proprietary software. The surface model is then utilised to create a near exact match of the articular surface in a knee femoral component. The sagittal geometry is preserved for the medial, trochlear and lateral ‘J’ curves with correction for disease as required. The coronal trochlear and condyle geometries are engineered surfaces that respect the laws of knee design for low contact stress. The bone cuts are individualised for each femoral component based on maximising bone preservation and utilising design rules that are based on finite elemental analysis and fatigue testing. The tibial articular surface geometry is derived from the femoral component. Separate medial and lateral inserts are supplied in varying thicknesses that allow precise balancing of the joint. Patient specific instrumentation is supplied with the implant that allows either femur first or tibial first techniques.
Hyaline articular cartilage has been known to
be a troublesome tissue to repair once damaged. Since the introduction
of autologous chondrocyte implantation (ACI) in 1994, a renewed
interest in the field of cartilage repair with new repair techniques
and the hope for products that are regenerative have blossomed.
This article reviews the basic science structure and function of
articular cartilage, and techniques that are presently available
to effect repair and their expected outcomes.
This conversation represents an attempt by several
arthroplasty surgeons to critique several abstracts presented over
the last year as well as to use them as a jumping off point for trying
to figure out where they fit in into our current understanding of
multiple issues in modern hip and knee arthroplasty.
To assess the clinical outcomes of patients undergoing ACI in the patellofemoral joint. Therapeutic study, Level II-1 (prospective cohort study). In a prospective study to determine the clinical effectiveness of autologous chondrocyte implantation 130 patients reached a minimum follow up of two years (range, 2–9 years, average 56.5 months) after treatment involving the patellofemoral articulation. There were 77 men (59%) and 53 women (41%) with an average age of 37.5 years (range, 15-57years). The treatment groups included I) isolated patella, n = 14; II) isolated trochlea, n = 15; III) patella plus trochlea, n = 5; IV) weight bearing condyle plus patella n = 19; V) weight bearing condyle plus trochlea, n = 52; VI) weight bearing condyle plus patella plus trochlea n = 25. The average surface area per patella, n = 63, was 4.72 cm2 and per trochlea, n = 98, was 5.8cm2. The average resurfacing per knee, n = 130, was 11.03cm2. This prospective outcome study demonstrated a significant postoperative improvement in quality of life as measured by the SF-36; WOMAC, Knee Society Score, modified Cincinnati Score and a patient satisfaction survey. There were 16 failures (12%) as a result of a patella or trochlea failure. Eighty percent of patients rated their outcomes as good or excellent, 18% rated outcome as fair, and 2% rated outcome as poor. ACI is effective in the patellofemoral joint and specifically is a complementary intervention for those patients that will predictably do poorly with an isolated Fulkerson Tibial Tubercle osteotomy.Level of evidence
Cartilage defects pretreated with marrow stimulation techniques will have an increased failure rate. The first 321 consecutive patients treated at one institution with autologous chondrocyte implantation for full-thickness cartilage defects that reached more than two 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. 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.Hypothesis
Results
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 (ACI). We present our experience with ACI after prior marrow stimulation. This study reviewed prospectively collected data for the first 321 consecutive patients treated at our institution with ACI for full-thickness cartilage defects that have reached more than 2 years of follow-up. 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 due to persistent symptoms. This includes treatment with revision ACI, allograft transplantation, partial or total knee replacement. 522 defects in 321 patients (325 joints) were treated with ACI. Patient average age was 35 (13–60), there were 185 men and 136 women, with a follow-up of 2–12 Years. On average, there were 1.7 lesions per patient (range, 1–5) with a transplant area of 4.8 cm2 per lesion and 8.1 cm2 per knee. 111 of these joints had previously undergone surgery that penetrated the subchondral bone: microfracture (n=25), abrasion chondroplasty (n=33), and drilling (n=53). 214 joints had no prior treatment that affected the subchondral bone and served as control. Within the marrow stimulation group, there were 27 (24%) failures compared with 17 (8%) failures in the control group. In our review of 321 patients, defects that had prior treatment affecting the subchondral bone failed at a rate 3 times that of non-treated defects. These data demonstrate that marrow stimulation techniques have a strong negative effect on subsequent cartilage repair, and should be used judiciously in larger cartilage defects that could require future treatment with ACI.
Traditionally, the results of autologous chondrocyte implantation (ACI) in the patellofemoral joint have been considered inferior to those in the weightbearing femoral condyles. This study investigated the clinical effectiveness of patellofemoral ACI in a large, single-surgeon cohort. This study reviewed prospectively collected data of patients treated with ACI for defects of the trochlea and/ or patella with a minimum follow-up of 2 years. Clinical outcomes were evaluated by SF-36; WOMAC, Knee Society Score, modified Cincinnati Score and a patient satisfaction survey. 130 patients reached a minimum follow-up of 2 years (2–9 years, average 56.5 months) after treatment involving the patellofemoral articulation. There were 77 men (59%) and 53 women (41%), the average age at the time of implantation was 37.5 years (15–57 years). The treatment groups included
isolated patella (n = 14); isolated trochlea (n = 15); patella plus trochlea (n = 5); weight-bearing condyle plus patella (n = 19); weightbearing condyle plus trochlea (n = 52); weightbearing condyle plus patella plus trochlea (n = 25). The average surface area of patellar and trochlear defects was 4.7 cm2 (n = 63) and 5.8 cm2 (n = 98), respectively. The average resurfacing per knee was 11 cm2. There were 16 failures (12%) that could be attributed to a patellar or trochlear defect. 80% of patients rated their outcome as good or excellent, 18% rated their outcome as fair, and 2% rated outcome as poor. ACI of the patellofemoral articulation provided a Significant improvement in quality of life as measured by functional scores and patient satisfaction survey. The failure rate was comparable to ACI used in other locations, such as the weightbearing femoral condyles.
