The 5.5-year results of MegaOATS--autologous transfer of the posterior femoral condyle: a case-series study

Implant system for large osteochondral defects

Issues with current treatments for osteochondral defects such as mosaicplasty and autologous chondrocyte implantation (ACI) are lack of donor material, problems associated with donor sites, necessity of second surgical intervention and cell expansion, difficult site preparation and implant fitting to match the surrounding tissue. This study presents the development of a patient specific implant system for focal osteochondral defects that addresses these issues. Using computer aided design and manufacturing techniques, computed tomography scans are utilized to design the implant and templates that facilitate site preparation to allow for precise and easy implantation of the designed perfectly fitting tissue replacement. Functionality of the system and accurate restoration of a defect is demonstrated by digital before/after comparison and with a prototype. With the presented implantation system larger defects in curved joint surfaces can be restored to an optimal shape in an easier procedure than for instance mosaicplasty. The proposed system potentially allows for later replacement of worn implants.

Management of Chondral Lesions of the Knee: Analysis of Trends and Short-Term Complications Using the National Surgical Quality Improvement Program Database

PURPOSE

To provide updated surgical trends of cartilage procedures differentiated by the classic groups of palliative, repair, and restorative modalities.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried from 2010-2016 for the following cartilage procedures: chondroplasty, microfracture, arthroscopic osteochondral autograft or allograft transplantation, open osteochondral autograft or allograft transplantation, and autologous chondrocyte implantation. Demographic variables and short-term (30-day) complications were analyzed with 1-way analysis of variance and post hoc analysis. Linear regression analysis was performed to analyze trends over time.

RESULTS

A total of 15,609 procedures performed between 2010 and 2016 were analyzed. On average, 342.2 ± 27.9 cartilage procedures were performed per 100,000 operations. There was a linear increase in the management of overall cartilage procedures per 100,000 operations (P = .002). There were also linear increases in arthroscopic osteochondral autograft transplantation, arthroscopic osteochondral allograft transplantation, open osteochondral autograft transplantation, open osteochondral allograft transplantation, and autologous chondrocyte implantation (P < .001, P = .037, P = .001, P = .006, and P = .002, respectively). Meniscectomy was the most frequently performed concomitant procedure (9.7%-64.2% of cases). Chondroplasty and microfracture showed no change in frequency over time (P = .140 and P = .720, respectively). The overall complication rate was 2.1% for chondroplasty, 1.4% for microfracture, 1.8% for arthroscopic osteochondral autograft transplantation, 1.0% for arthroscopic osteochondral allograft transplantation, 1.4% for open osteochondral autograft transplantation, 1.1% for open osteochondral allograft transplantation, and 0.75% for autologous chondrocyte implantation. Deep vein thrombosis was the most common complication, occurring in 0.4% to 1.0% of cases. No statistically significant difference was found in complication rates between procedures (P = .105).

CONCLUSIONS

Cartilage restoration is becoming an increasingly popular modality to address chondral defects. Minimal complication rates suggest that these procedures may be safely performed concomitantly with other interventions.

LEVEL OF EVIDENCE

Level IV, retrospective database analysis.

Preservation of Knee Articular Cartilage

Hyaline articular cartilage is critical for the normal functioning of the knee joint. Untreated focal cartilage defects have the potential to rapidly progress to diffuse osteoarthritis. Over the last several decades, a variety of interventions aiming at preserving articular cartilage and preventing osteoarthritis have been investigated. Reparative cartilage procedures, such as microfracture, penetrate the subchondral bone plate in effort to fill focal cartilage defects with marrow elements and stimulate fibrocartilaginous repair. In contrast, restorative cartilage procedures aim to replace the defective articular surface with autologous or allogeneic hyaline cartilage. This review focuses on the preservation of articular cartilage, and discusses the current reparative and restorative surgical techniques available for treating focal cartilage defects.

[Current overview of cartilage regeneration procedures]

BACKGROUND

Cartilage is an avascular, alymphatic and non-innervated tissue with limited intrinsic repair potential. The high prevalence of cartilage defects and their tremendous clinical importance are a challenge for all treating physicians.

AIM

This article provides the reader with an overview about current cartilage treatment options and their clinical outcome.

METHODS

Microfracture is still considered the gold standard in the treatment of small cartilage lesions. Small osteochondral defects can be effectively treated with the autologous osteochondral transplantation system. Larger cartilage defects are successfully treated by autologous membrane-induced chondrogenesis (AMIC) or by membrane-assisted autologous chondrocyte implantation (MACI).

CONCLUSION

Despite limitations of current cartilage repair strategies, such procedures can result in short- and mid-term clinical improvement of the patients. Further developments and clinical studies are necessary to improve the long-term outcome following cartilage repair.

Good results with minimally invasive unicompartmental knee resurfacing after 10-year follow-up

The current study was designed to determine (1) 10-year implant survival and (2) patient's self-reported functional outcome in a single surgeon's consecutive cohort of patients who had undergone minimally invasive unicondylar resurfacing with a modified cementation technique utilizing a cobalt-chromium femur/inlaid all-PE tibia, fixed-bearing unicompartmental prosthesis. We included 344 consecutive patients (361 knees) who had received the study device between January 2002 and December 2005 in this retrospective study. After 10 years, 78 patients (78 knees) had died, 59 (59 knees) were lost to follow-up and four (four knees) did not participate. Thirteen knees (11 patients) were revised after a mean of 5.8 ± 1.9 years. Hence, the study population at follow-up comprised 192 patients (207 knees). Ten-year implant survival was 94.6% (95% confidence interval, 90.9-96.8%). The Forgotten Joint Score and Oxford Knee Score were 68.9 ± 28.9 and 39 ± 9.1, respectively. Excellent survivorship and clinical outcomes were obtained with UKA with an inlaid all-PE tibia with a modified cementation technique.

Bilateral cartilage T2 mapping 9 years after Mega-OATS implantation at the knee: a quantitative 3T MRI study

OBJECTIVE

To evaluate morphological and quantitative MR findings 9 years after autograft transfer of the posterior femoral condyle (Mega-OATS) and to correlate these findings with clinical outcomes. Quantitative MR measurements were also obtained of the contralateral knee and the utility as reference standard was investigated.

DESIGN

Both knees of 20 patients with Mega-OATS osteochondral repair at the medial femoral condyle (MFC) were studied using 3T MRI 9 years after the procedure. MR-sequences included morphological sequences and a 2D multislice multiecho (MSME) spin echo (SE) sequence for quantitative cartilage T2 mapping. Cartilage segmentation was performed at the cartilage repair site and six additional knee compartments. Semi-quantitative MR observation of cartilage repair tissue (MOCART) scores and clinical Lysholm scores were obtained. Paired t-tests and Spearman correlations were used for statistical analysis.

RESULTS

Global T2-values were significantly higher at ipsilateral knees compared to contralateral knees (42.1 ± 3.0 ms vs 40.4 ± 2.6 ms, P = 0.018). T2-values of the Mega-OATS site correlated significantly with MOCART scores (R = -0.64, P = 0.006). The correlations between MOCART and Lysholm scores and between absolute T2-values and Lysholm scores were not significant (P > 0.05). However, higher T2 side-to-side differences at the femoral condyles correlated significantly with more severe clinical symptoms (medial, R = -0.53, P = 0.030; lateral, R = -0.51, P = 0.038).

CONCLUSIONS

Despite long-term survival, 9 years after Mega-OATS procedures, T2-values of the grafts were increased compared to contralateral knees. Clinical scores correlated best with T2 side-to-side differences of the femoral condyles, indicating that intraindividual adjustment may be beneficial for outcome evaluation.

Valgus bracing in symptomatic varus malalignment for testing the expectable "unloading effect" following valgus high tibial osteotomy

PURPOSE

The purpose of this study was to evaluate whether the expectable postoperative pain relief following valgus high tibial osteotomy (HTO) is reliably predictable with the temporary use of an unloading knee brace preoperatively.

METHODS

Fifty-seven patients with symptomatic varus malalignment were treated with a valgus producing unloading knee brace for 6-8 weeks. The pain intensity in the respective knee compartment was monitored using the visual analogue scale (VAS) before and following this treatment. A "positive" Brace-Test was defined as a pain relief medially without initiated symptoms laterally. In these cases, a valgus HTO was suggested as a promising surgical option. Patients who were subsequently operated were clinically re-evaluated 1 year postoperatively to compare the postoperative outcome with the result of the Brace-Test.

RESULTS

The mean VAS score decreased from 6.7 [standard deviation (SD) 1.6] to 2.5 points (SD 1.7) (p < 0.001) following the Brace-Test. Overall, 48 patients had a positive test. A valgus HTO was performed in 29 of them. The mean postoperative VAS score was 1.9 (SD 1.7) points with no difference to the result of the test (n.s.). Nineteen patients with a positive test initially decided for a conservative treatment. In three of nine patients with a negative test, a total knee replacement was performed.

CONCLUSION

This study shows that the temporary use of an unloading valgus producing knee brace may well predict future outcome of HTO surgery in terms of expectable postoperative pain relief. The Brace-Test gives both the patient and the orthopaedic surgeon more detailed preoperative information, especially in critical or borderline indications. Thus, it is a useful tool to test the unloading effect before indicating an HTO.

LEVEL OF EVIDENCE

III.

Practice in rehabilitation after cartilage therapy: an expert survey

BACKGROUND

Current cartilage therapy modalities like microfracture, ACT/MACT, AMIC or osteochondral transplantation are important tools to treat symptomatic (osteo)chondral lesions of the knee joint. However, until now there exists no high-level evidence based accepted rehabilitation plan for the postoperative treatment.

HYPOTHESIS/PURPOSE

This survey describes the predominantly used rehabilitation plan as implemented by expert musculoskeletal surgeons for operatively treated (osteo)chondral lesions.

STUDY DESIGN

Survey and systematic review.

METHODS

An electronic questionnaire covering general and specific items concerning aftercare following cartilage therapy in the knee joint was designed and disposed to analyze rehabilitation programs among a population of expert musculoskeletal surgeons of the AGA (Society of arthroscopy and joint surgery). All instructors (304 in 01/2011) were included into the survey. A total of 246 (80.9 %) instructors answered the questionnaire.

RESULTS

The predominant used therapy to treat cartilage lesions is microfracture and for osteochondral lesions the osteochondral transplantation. Physiotherapy starts directly after surgery and takes more than 6 weeks. Most surgeons do not immobilize patients after surgery and use partial weight-bearing for up to 5 weeks. The change from partial to full weight-bearing is done step-wise with a 20-kg/week increase. Free ROM is allowed by the majority of instructors (55 %) directly after surgery. A CPM-device is also used directly and up to 5 weeks. Swimming and biking are allowed after 6 weeks, running is allowed after 12 weeks and contact sports after 24 weeks. Most instructors do not use braces in the aftercare procedure, but nearly all (93 %) prescribe crutches. Typical drugs used during the aftercare are NSAID, Heparin and antibiotics. For most instructors (79 % respectively 75 %) knee stability and a straight leg axis are necessary for a successful cartilage therapy. If a concomitant therapy like ACL reconstruction or an osteotomy is performed, aftercare is mainly dependent on cartilage therapy (62 % respectively 59 % of instructors).

CONCLUSIONS

Today there exists no detailed rehabilitation program for treatment after a cartilage-related operation on the basis of an evidence-based level I study. The reason might be that many variables contribute to a specific aftercare procedure. Therefore, the survey of experienced surgeons may help to identify the most promising rehabilitation regime for today, at least until evidence-based level I studies are accomplished.

Treatment of knee cartilage defect in 2010

Treatment of knee cartilage defect, a true challenge, should not only reconstruct hyaline cartilage on a long-term basis, but also be able to prevent osteoarthritis. Osteochondral knee lesions occur in either traumatic lesions or in osteochondritis dissecans (OCD). These lesions can involve all the articular surfaces of the knee in its three compartments. In principle, this review article covers symptomatic ICRS grade C or D lesions, depth III and IV, excluding management of superficial lesions, asymptomatic lesions that are often discovered unexpectedly, and kissing lesions, which arise prior to or during osteoarthritis. For clarity sake, the international classifications used are reviewed, for both functional assessment (ICRS and functional IKDC for osteochondral fractures, Hughston for osteochondritis) and morphological lesion evaluations (the ICRS macroscopic evaluation for fractures, the Bedouelle or SOFCOT for osteochondritis, and MOCART for MRI). The therapeutic armamentarium to treat these lesions is vast, but accessibility varies greatly depending on the country and the legislation in effect. Many comparative studies have been conducted, but they are rarely of high scientific quality; the center effect is nearly constant because patients are often referred to certain centers for an expert opinion. The indications defined herein use algorithms that take into account the size of the cartilage defect and the patient's functional needs for cases of fracture and the vitality, stability, and size of the fragment for cases of osteochondritis dissecans. Fractures measuring less than 2 cm(2) are treated with either microfracturing or mosaic osteochondral grafting, between 2 and 4 cm(2) with microfractures covered with a membrane or a culture of second- or third-generation chondrocytes, and beyond this size, giant lesions are subject to an exceptional allografting procedure, harvesting from the posterior condyle, or chondrocyte culture on a 3D matrix to restore volume. Cases of stable osteochondritis dissecans with closed articular cartilage can be simply monitored or treated with perforation in cases of questionable vitality. Cases of open joint cartilage are treated with a PLUS fixation if their vitality is preserved; if not, they are treated comparably to osteochondral fractures, with the type of filling depending on the defect size.

Cartilage repair and joint preservation: medical and surgical treatment options

BACKGROUND

Articular cartilage defects are most often caused by trauma and osteoarthritis and less commonly by metabolic disorders of the subchondral bone, such as osteonecrosis and osteochondritis dissecans. Such defects do not heal spontaneously in adults and can lead to secondary osteoarthritis. Medications are indicated for symptomatic relief. Slow-acting drugs in osteoarthritis (SADOA), such as glucosamine and chondroitin, are thought to prevent cartilage degeneration. Reconstructive surgical treatment strategies aim to form a repair tissue or to unload compartments of the joint with articular cartilage damage.

METHODS

In this article, we selectively review the pertinent literature, focusing on original publications of the past 5 years and older standard texts. Particular attention is paid to guidelines and clinical studies with a high level of evidence, along with review articles, clinical trials, and book chapters.

RESULTS

There have been only a few randomized trials of medical versus surgical treatments. Pharmacological therapies are now available that are intended to treat the cartilage defect per se, rather than the associated symptoms, yet none of them has yet been shown to slow or reverse the progression of cartilage destruction. Surgical débridement of cartilage does not prevent the progression of osteoarthritis and is thus not recommended as the sole treatment. Marrow-stimulating procedures and osteochondral grafts are indicated for small focal articular cartilage defects, while autologous chondrocyte implantationis mainly indicated for larger cartilage defects. These surgical reconstructive techniques play a lesser role in the treatment of osteoarthritis. Osteotomy near the knee joint is indicated for axial realignment when unilateral osteoarthritis of the knee causes axis deviation.

CONCLUSION

Surgical reconstructive techniques can improve joint function and thereby postpone the need for replacement of the articular surface with an artificial joint.

Surgical implants and technologies for cartilage repair and preservation of the knee

Focal lesions of the articular cartilage of the knee can be managed with a variety of products and technologies in an attempt to restore function to the afflicted joint and forestall the need for possible total knee arthroplasty. Among these approaches are non-implant-based procedures (arthroscopic chondroplasty and microfracture), grafting procedures (autografts/mosaicplasty and allografts), cell-based procedures (autologous chondrocyte implantation) and nonbiologic implants (metallic plugs and cell-free polymers). For each clinically established procedure there are also a number of investigational variations that aim to improve the in vivo quality of the regenerated/restored cartilage surface. This article analyzes existing and developing non-implant- and graft-based technologies for the repair or restoration of the articular cartilage of the knee based on a review of the published literature.

Chondral repair of the knee joint using mosaicplasty

Mosaicplasty grafting is performed by transferring one or more cylindral osteochondral autografts from a low weight-bearing area of the knee towards the defective site, usually the femoral condyle. Numerous biomechanical, histological, animal and clinical studies have evaluated the different technical aspects of this procedure. The preoperative work-up encompasses an evaluation of functional disturbances, alignment, knee stability and imaging (CT arthrography or MRI with cartilage sequences). The surgical procedure includes harvesting the grafts by mini-arthrotomy of the medial or lateral trochlea and a stage for arthroscopic graft insertion. The ICRS classification is used to describe the defect (area, depth, location) before and then after debridement. A few, large diameter grafts are harvested from the trochlea across from the defect. The graft plugs are transplanted by press-fit, flush with the cartilage, along a convergent plane in recipient sockets of exactly the same depth. Each stage, harvesting, drilling and insertion is repeated until all the full-thickness gap region has been covered. Postoperative movement is free but weight-bearing is delayed for 2 to 4 weeks. Mosaicplasty is indicated in young patients (under 50), with symptomatic chondral or osteochondral defects of less than 3 cm in the weight-bearing part of the femoral condyle. Pre-osteoarthritis is an absolute contraindictation for this procedure. Any misalignment (of more than 5°) or sagittal instability is treated simultaneously. This is a difficult and demanding procedure.

The posterior femoral condyles: a potential donor site for mosaic-like osteochondral autograft?

PURPOSE

The purpose of this study was to assess whether it was possible to harvest plugs from the posterior femoral condyles with a standard mosaicplasty instrumentation through retroligamentous approaches and whether the plugs harvested from the posterior condyles presented the same characteristics as those harvested from the standard donor sites regarding the length, cartilage thickness, and cartilage angle.

METHODS

An anatomic study has been conducted on 15 cadaveric knees. Osteochondral plugs were harvested with a 10-mm tubular chisel from the standard donor sites and from the posterior condyles. The plugs were analyzed regarding the length, cartilage thickness, and angle between the axis of the plug and the cartilage surface (cartilage angle).

RESULTS

Two plugs harvested from the posterior condyles were not suitable for implantation. Between the different donor sites, the cartilage thickness of the lateral side of the intercondylar notch was significantly thinner (mean, 1.57 mm; SD, 0.46) than the other standard donor sites (P < .05). The mean cartilage thickness was 2.35 mm (SD, 0.72) for the posteromedial condyle and 1.96 mm (SD, 0.67) for the posterolateral condyle. The mean angle was 19.7° (SD, 15.5) for the posteromedial condyle and 13.8° (SD, 8.6) for the posterolateral condyle.

CONCLUSIONS

Whereas the cartilage thickness of the posterior condyles is comparable to other donor sites, the technical difficulty in obtaining plugs perpendicular to the articular surface precludes the use of the posterior condyles in anything but the rarest circumstances. Routine use of these 2 donor sites cannot be recommended.

CLINICAL RELEVANCE

The posterior condyles cannot be proposed as a donor site for osteochondral autograft with a mosaicplasty instrumentation because it is difficult to obtain plugs with a perpendicular cartilage surface from this localization.

[Autologous transfer of the posterior femoral condyle for large osteochondral lesions of the knee: 5-year results of the Mega-OATS technique]

BACKGROUND

Large osteochondral defects of the weight-bearing zones of the femoral condyles in young and active patients were treated by autologous transfer of the posterior femoral condyle. This technique is a salvage procedure and aims at pain-free mobility of patients.

MATERIAL AND METHODS

Between July 1999 and December 2000, 18 patients were operated on. Sixteen patients were evaluated using the Lysholm score. X-rays were done, and eight individuals underwent magnetic resonance imaging (MRI) analysis. The average age at the date of surgery was 37.4 (15-59) years, and the mean follow-up time was 55.2 (46-62) months. The mean defect size was 5.4 cm(2) (3.1-7.1). Trauma or osteochondrosis dissecans was pathogenetic in 81%.

RESULTS

The Lysholm score showed a significant (p=0.001) increase from a preoperative median of 65.0 to a postoperative median of 86.0 points. Fifteen patients returned to sport activities. X-rays showed a rounding of the osteotomy edge in 12 patients and a partial bone-dense remodelling of the posterior femoral condyle in 11 patients. All MRI examinations showed vital and congruent grafts.

CONCLUSION

Thus, the procedure is recommended for treating large and deep focal osteochondral lesions in the weight-bearing zone of the femoral condyle.

Chondrocyte death and cartilage degradation after autologous osteochondral transplantation surgery in a rabbit model

BACKGROUND

Autologous osteochondral transplantation surgery requires an impact force on the graft that may cause chondrocyte death and matrix degradation. This study attempted to determine the degree to which this occurs in a rabbit model shortly after the procedure.

HYPOTHESIS

Impaction of a press-fit autologous osteochondral graft in vivo results in chondrocyte necrosis, apoptosis, and matrix degradation at early time points.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty New Zealand White rabbits underwent unilateral osteochondral transplantation (OT) surgeries, and 10, bilateral sham surgeries. Fifteen animals were sacrificed at time zero (10 sham-0 limbs, 10 OT-0 limbs), and 15, 4 days after surgery (10 sham-4 limbs, 10 OT-4 limbs). Chondrocyte viability/necrosis was determined with cell vital staining. Chondrocyte apoptosis was determined by TUNEL, Bcl-2, and M30 assays. Cartilage matrix degradation was determined by routine light and polarized light microscopy and COL2-3/4C(short) immunohistochemistry. Statistical analysis was performed with a 2-way analysis of variance (P < .05).

RESULTS

There were significantly fewer viable cells in OT-4 than in sham-4. A similar difference in cell viability was found in OT-0 versus sham-0. There were more TUNEL-positive cells in OT-4 as compared with OT-0, sham-0, and sham-4; however, there was little or no staining of Bcl-2 and M30. Mankin scores were higher in both OT groups versus both sham groups at time zero and day 4. The OT-4 group had positive staining for COL2-3/4C(short) that corresponded with a loss of collagen birefringence at the superficial zone.

CONCLUSION

Osteochondral transplantation procedures performed by tamping a press-fit graft induce chondrocyte necrosis and matrix metalloproteinase-mediated cartilage matrix degradation. However, apoptosis was not found to a major contributor to cell death in this model.

CLINICAL RELEVANCE

Results of osteochondral transplantation procedures may be improved by atraumatic insertion and fixation techniques or by pharmacologic agents that can block these degradative processes.