Autologous Osteochondral Transfer Research Articles

Primary Autologous Osteochondral Transfer Shows Superior Long-Term Outcome and Survival Rate Compared With Bone Marrow Stimulation for Large Cystic Osteochondral Lesion of Talus

To compare the results of bone marrow stimulation (BMS) versus autologous osteochondral transfer (AOT) as primary surgical option for large cystic osteochondral lesion of talus (OLT) and to further distinguish factors associated with clinical failures and overall survival. We retrospectively analyzed patients with symptomatic large cystic OLT (>300 mm3) who underwent either primary BMS or AOT between January 2001 and January 2016 with a minimum follow-up of 36 months. Lesion surface area and volume were measured on magnetic resonance imaging. Clinical outcomes were assessed using pain visual analog scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) score, and Foot and Ankle Outcome Score (FAOS). Survival outcomes and factors associated with clinical failures were evaluated using Kaplan-Meier analysis and Cox regression analyses, respectively. Fifty of the total 853 patients had large cystic OLTs. Thirty-two patients underwent primary BMS, and 18 patients underwent primary AOT. Mean follow-up period was 118 months, and average lesion surface area and volume were 152.8 mm2 and 850.7 mm3, respectively. The primary AOT group showed significantly superior improvements in clinical outcomes compared with the BMS group at last follow-up (P= .001). Fourteen patients in the primary BMS group and 2 patients in the primary AOT group experienced clinical failure. Kaplan-Meier analysis showed a superior survival rate of primary AOT (P= .042). Syndesmosis widening (hazard ratio 12.361; P= .004) and large lesion surface area (hazard ratio 1.011; P= .014) were significant relative risks of clinical failure in the primary BMS group. However, lesion volume showed no significant relationship with clinical failure. Long-term results of primary AOT showed superior clinical improvements and survival rate in treating large cystic OLT. Risk factors for failure in the primary BMS group were large lesion surface area and syndesmosis widening. Retrospective comparative study LEVEL OF EVIDENCE: III.

Femoral Head Fracture with Hip Dislocation Treated by Autologous Osteochondral Transfer (Mosaicplasty): A Case Report

Femoral Head Fracture with Hip Dislocation Treated by Autologous Osteochondral Transfer (Mosaicplasty): A Case Report

Successful treatment of avascular necrosis of the distal femoral condyle with osteochondral autograft in an HIV positive woman: A case report

Treatment of avascular necrosis is challenging and requires patient individual treatment planning. A 26-year-old HIV positive woman presented with increasing pain and stiffness in her left knee. We diagnosed an avascular necrosis of the knee with a severely limited range of movement. During her treatment, she also developed an avascular necrosis of both hips. To minimize the risks of prosthetic joint infection in an immunocompromised patient, we decided to perform a hip arthroplasty with an autologous full-thickness osteochondral transfer of the femoral head to the femoral condyle. Despite a lack of compliance and physiotherapy, the symptoms and range of movement significantly improved postoperatively, without the patient being pain-free. We propose that in cases of simultaneous avascular necrosis of hip and knee, a large autologous transfer is an option to prolong or prevent knee arthroplasty, especially in patients with risk factors for a poor outcome of arthroplasty.

Cartilage Restoration Surgery: Incidence Rates, Complications, and Trends as Reported by the American Board of Orthopaedic Surgery Part II Candidates

To evaluate the current status of advanced cartilage restoration procedures among newly trained orthopaedic surgeons in the United States. The American Board of Orthopaedic Surgery database was queried to identify all advanced cartilage restoration procedure cases submitted by American Board of Orthopaedic Surgery part II board certification examination candidates from 2003 to 2015. All documented autologous chondrocyte implantation, autologous osteochondral transfer, osteochondral allograft transplantation, and marrow stimulation techniques (MSTs) procedures were analyzed. Analysis was performed to describe trends in annual incidence, types of complications, concomitant procedures, and geographical differences in incidence of advanced cartilage procedures. From 2003 to 2015, a total of 2,827 surgeons submitted 7,522 cartilage restoration procedures, with 7,060 cases documented as MST (80.01%). The number of cartilage cases decreased significantly from 2003 to in 2015 (P <.001), with MST having the largest decline (P < .001). The incidence of open osteochondral allograft transplantation (odds ratio= 1.35; P= .023) and open autologous osteochondral transfer (odds ratio= 0.84; P= .004) increased over the study period. Overall, the majority of patients (57.0%) were male; however, female patients were on average significantly older than male patients (P < .001). Cartilage procedures were performed concomitantly with a realignment osteotomy procedure in 1.7% of cases. The incidence of surgical complications increased throughout the study period from 2.9% in 2003 to 9.5% in 2015 (P<.001). Cartilage restoration procedures, specifically MSTs, are being decreasingly performed among recently trained orthopaedic surgeons. In contrast, complication rates have been increasing since 2003, demonstrating a possible paradigm shift toward more complex cartilage procedures, specifically osteochondral grafting procedures. This study demonstrates a significant decline in the use of MSTs by recently trained orthopaedic surgeons. In addition, an increase in several more complex cartilage restoration procedures was found. Taken in sum, these changes may reflect a shift in residency and fellowship training away from marrow stimulation procedures that elicit a fibrocartilage reparative tissue and toward more complex procedures that provide a more hyaline-like articular cartilage surface.

Arthroscopic Surgical Technique for an Acute Talar Dome Osteochondral Lesion in a Professional Rugby League Player

Talar osteochondral lesions represent challenging clinical entities, particularly in high-demand athletes. Surgical treatment of large lesions often requires a 2-step procedure, or the use of osteotomy in the case of autologous osteochondral transfer, which can delay return to sport. A professional rugby league player underwent surgery for a complex injury to the ankle. A talar osteochondral lesion with a maximal diameter of 15 mm was treated in an arthroscopic fashion using the cartilage taken from the completely displaced osteochondral fragment. Cartilage was cut into chips and combined with bone graft product containing platelet-derived growth factor and a porous collagen scaffold. Autologous cartilage was then reimplanted arthroscopically. The patient was allowed full ankle motion from 2 weeks postoperatively, and weightbearing was commenced at 6 weeks. Follow-up imaging and functional outcomes, including return to sport, were assessed at regular intervals. The patient was able to return to professional rugby league by 23 weeks postoperatively. Magnetic resonance imaging at 16 months postoperatively showed restoration of the subchondral plate and osseous infill. At final follow-up, the patient remained pain free and was playing at preinjury level. This report describes good outcomes using a novel, 1-step cartilage repair technique to treat a large talar osteochondral lesion in a professional athlete. Level V: Expert opinion.

Outcomes following Structural Grafting of Distal Femoral Osteochondral Injuries in Patients Aged 40 Years and Older.

Osteochondral lesions of the distal femur represent a challenging clinical entity, particularly in patients > 40 years of age. Microfracture has demonstrated inferior results in this population with clinical deterioration beyond 1 to 2 years postoperatively. Limited evidence exists to support alternative cartilage restoration procedures. The purpose of this study was to report functional outcomes and activity levels following cartilage restoration procedures in patients > 40 years with symptomatic distal femoral osteochondral lesions. From 2000 to 2012, 61 patients with distal femoral osteochondral injuries were retrospectively identified. Mean follow-up was 3.6 ± 1.4 years; mean age was 51.6 years (range 40-71); 59% were male. Of 61 patients, 35 patients (57%) were treated with synthetic scaffold (SS) plugs (off-label), 14 (23%) with osteochondral allograft (OCA), and 12 (20%) with autologous osteochondral transfer (AOT). Validated outcome measures including activity of daily living (ADL) score, International Knee Documentation Committee (IKDC) subjective evaluation form, and Marx activity scale (MAS) were used. The average lesion size was 3.8 ± 2.1 cm2. Lesion size was significantly greater in the OCA group (5.8 ± 1.8 cm2), compared with the SS (3.2 ± 1.9 cm2) and AOT group (3.3 ± 1.8 cm2, p ≤ 0.0024). Collectively, outcome scores for the entire population demonstrated significant improvement in ADL (61.36 ± 17.76-76.81 ± 17.2, p < 0.0001) and IKDC scores (40.28 ± 13.28-61.84 ± 20.83, p < 0.001) from baseline to final follow-up, with no significant change in MAS (4.19 ± 5.13-2.59 ± 3.92, p = 0.07). Similarly, subgroup analysis identified that all treatment groups (SS, OCA, and AOT) demonstrated significant improvement in ADL and IKDC scores from preoperative to final postoperative visit (p ≤ 0.0361). MAS scores were maintained in the OCA and AOT groups (p ≥ 0.1704), but significantly decreased in the SS group (4.3 ± 5.2-2.7 ± 4.11, p = 0.0163). Ten patients (16.3%) required revision surgery at a mean of 4.4 years (range 0.3-13.4 years). Cartilage restoration procedures using structural grafts are successful in patients 40 years and older, with improved pain and functional outcome scores compared with preoperative baseline scores. OCA and AOT should primarily be used, given recent concerns with SS implants.

Autologous osteochondral transfer for the treatment of full-thickness defects in patients with or without ACL reconstruction. Results with 7 years follow-up

Objectives:The aim of this study was to evaluate the results of autologous osteochondral transfer for the treatment of cartilage defects in 2 groups of patients: The first with an isolated osteochondral injury and the other with associated anterior cruciate ligament (ACL) injury treated in one stage surgeryMaterials and Methods:We retrospectively evaluated 25 patients with symptomatic focal full-thickness chondral lesions in the femoral condyles during the years 2003-2009, with a minimum of 5 years of follow up. The patients were divided into 2 groups: Group A: 10 patients with associated ACL injury, and Group B: 15 patients with an isolated osteochondral lesion. Clinical outcome was analyzed by Lysholm and IKDC scores.Results:There was an improvement of all scores in both groups. There were no significant differences between the groups in the IKDC (82/84) and Lysholm (87/86) scores. The mean age at the time of assessment for group A was 46 years and 44 for the group B. The mid term follow-up was 96 months for group A and 103 months for group B. Two complications were recorded in group A: 1 infection and 1 arthrofibrosis. 2 complicationsoccurred in group B: 2 arthrofibrosis.Conclusion:The results of the mosaicplasty for the focal full-thickness chondral lesions in the femoral condyles are favorable after 5 years of follow up. There was no difference between the associated or not ACL injury.

Particulated Juvenile Articular Cartilage Implantation in the Knee: A 3-Year EPIC-µCT and Histological Examination.

Objective:The goal of this report is to describe the outcome of sequential particulated cartilage allograft and autologous osteochondral transfer treatments for an osteochondral lesion of the medial femoral condyle.Methods:A 44-year-old woman was treated with a particulated juvenile articular cartilage allograft (DeNovo NT) for a chondral lesion of the knee. As a result of continued pain, she had 2 further surgeries, including an autologous osteochondral transfer system procedure and finally a unicondylar knee arthroplasty. At the final procedure, the areas of the allograft and autograft tissue were biopsied for histological evaluation. The quality of the residual cartilage tissue was assessed first by equilibrium partitioning of an ionic contrast agent via micro–computed tomography (EPIC-µCT), and then by hematoxylin and eosin, Safranin O staining, and polarized light microscopy.Results:Despite showing good healing at 7 months postsurgery by MRI, at 28 months post DeNovo NT tissue implantation the excised cartilage tissue was heterogeneous, with some regions of hyaline-like cartilage and some regions of fibrocartilage. The later mosaicplasty may have helped maintain hyaline-like cartilage of the DeNovo NT tissue in its vicinity.Conclusion:This case report describes the cartilage repair tissue produced by DeNovo NT implantation and compares it with autologous osteochondral plug tissue.

Response to comment on Gagala et al.: Clinical and radiological outcomes of treatment of avascular necrosis of the femoral head using autologous osteochondral transfer (mosaicplasty). Preliminary report

Dear Dr. Siddhartha Sharma, Thank you very much in your interest in our article [1]. We would like to answer your questions point by point as below. The OATS/allograft was performed as a salvage procedure in patients with ARCO III and IV who refused total hip replacement and asked for a joint preserving operation. The use of OATS in osteonecrosis of the femoral head (ONFH) was approved by the local ethical committee. A written consent was obtained from every single patient. MRI is a better tool to observe ONFH progression and graft incorporation than X-rays, but unfortunately the Polish National Health Fund covers the cost of MRI examination performed as a diagnostic but not as a scientific method. Follow-up examinations from recently published papers presenting novel ONFH treatment also use only X-ray results [2]. The exact location of drill bits for OATS was planned upon preoperative MRI examination. We did not have any problems either in necrotic segment identification during the procedure or in inspection of complete removal. Bone defects were packed with morsellised allogenic bone; no osteochondrall allografts were implanted in the OATS/allograft group. The indication for subtrochanteric osteotomy in one case was excessive femoral neck anteversion. Up to 2013, seven papers, mainly case reports and case series, were published presenting outcomes of 31 hips in which OATS had been performed for different indications [3–9]. The aim of our preliminary report was to present the outcomes of OATS in 21 patients with ONFH and to share with the orthopaedic community our experiences of this novel technique. As mentioned above our paper is a preliminary report so we think there is no need for a control group to confirm our conclusions.

Comment on Gagala et al.: Clinical and radiological outcomes of avascular necrosis of the femoral head using autologous osteochondral transfer (mosaicplasty). Preliminary report

Dear Sir, We read with great interest the article by Gagala et al. entitled “Clinical and radiological outcomes of avascular necrosis of the femoral head using autologous osteochondral transfer (mosaicplasty). Preliminary report” [1]. Although the authors presented their initial results with this novel technique, there are several intriguing points that we think need to be elaborated upon: It is a well-known fact that the results of femoral-head-preserving procedures are dismal once collapse has occurred [Association Research Circulation Osseous (ARCO) stage III] [2, 3]. The only study reporting the use of autologous osteochondral transfer (OATS) in postcollapse stage of osteonecrosis of the femoral head (ONFH), by Rittmeister et al. [4], confirms these findings. We would like to know the authors’ rationale for choosing OATS/allograft procedure in ARCO stages III–IV when the existing literature does not recommend such procedures for these stages. Also, the authors should clarify whether ethical clearance was sought for this procedure and informed written consent was obtained from the study participants. A major objective of the study was to evaluate the radiological outcome of the OATS procedure. The authors used only X-rays for radiological evaluation. We believe that magnetic resonance imaging (MRI) would have been a better tool to identify graft incorporation and disease progression postoperatively. The authors need to elucidate their OATS surgical technique. How did they determine the exact location of the drill holes for the OATS procedure intraoperatively? How did they ensure that all necrotic bone had been removed? Was any intraoperative imaging used? The necrotic segment can be difficult to identify on naked-eye inspection when the femoral head has not collapsed, and ARCO stage IIa lesions can be difficult to identify even on image intensifiers. Clarification is also needed regarding the use of morcellised allograft for ARCO stages IIC, III, and IV. How was the allograft processed and stored prior to usage? It is a well-known fact from the literature on knee articular cartilage injuries that OATS can provide coverage only for lesions up to two centimetres. For larger lesions, allografts obtained from a fresh osteoarticular, size-matched hemicondyle are recommended [3]. Even if the defect in the femoral head (after curettage) was packed with allograft, it is hard to imagine that the authors were able to provide adequate cartilaginous coverage to the diseased femoral head, a fact that may very well have accounted for the failure of this procedure. What was the authors’ indication for performing a subtrochanteric derotation osteotomy in one case? The natural history of ONFH, especially in the precollapse stage, is widely variable, and lesions may not progress for years. Therefore, any surgical option to defer arthroplasty should be followed up for at least five years, and ideally ten. Only seven patients in the study had a follow-up of at least five years. We therefore feel that the authors’ follow-up is inadequate. The authors concluded that treatment with OATS is neither better nor worse than other joint-preservation options. However, there was no control group. Furthermore, this pilot study had just 21 patients, with small number of patients in each ARCO stage, thereby precluding any meaningful statistical analysis. Comparison of these results with those of other studies in the literature also risks introduction of bias in the patient characteristics, risk factors for ONFH and the expertise of the operating surgeon. Therefore, we feel that such conclusions should be avoided. To conclude, we feel that more information in the form of large, multicentre studies is needed before we can judge the usefulness of the OATS procedure for ONFH. It would also help if the authors reported the long-term results of their surviving hips.

Clinical and radiological outcomes of treatment of avascular necrosis of the femoral head using autologous osteochondral transfer (mosaicplasty). Preliminary report

PurposeThe purpose of this study was to evaluate clinical and radiological outcomes of autologous osteochondral transfer (OATS) for femoral head osteonecrosis.MethodsTwenty-one hips in 20 patients (one woman and 19 men), average patients' age at the time of surgery of 35.4 (range 20–56) years, were treated with OATS for osteonecrosis of the femoral head (ONFH). Seven patients at pre-collapse ARCO stages IIA and IIB were treated with OATS alone. Thirteen patients with large pre-collapse ARCO IIC and post-collapse ARCO III and IV were treated with OATS and morselised bone allografts (OATS/allograft). Harris hip score (HHS) was used for clinical evaluation of outcomes; X-rays were performed to examine the evolution of the disease. Kaplan-Meier survival curves were used to determine the failure of the procedures with conversion to THR defined as endpoint.ResultsFollow-up of patients treated with OATS alone was 46.14 (range 18–75) months with HHS improvement from a preoperative mean of 42 to 87.85 points at the latest follow-up examination. Only one patient in this group needed a revision operation with THR. The survival for this group of patients was 85.71 % at four years. Follow-up of patients treated with AOTS/allograft was 32.7 (range 7–84) months with HHS improvement from a preoperative mean of 35.2 to 65.7 points at the latest follow-up examination. One patient died six months after the surgery. There were five conversions to THR because of femoral head collapse in this group of patients with survival of 61.54 % at three years.ConclusionThe use of osteochondral grafts offers the possibility of successful treatment for ONFH at small and medium pre-collapse stages. The outcomes of large pre-collapse and post-collapse stages were below our expectations. OATS is a time buying procedure for young patients as it may defer total hip replacement.

The use of osteochondral allografts in the management of cartilage defects.

Large symptomatic osteochondral defects in a young active population represent a therapeutic challenge for orthopedic surgeons, since standard interventions such as debridement, microfracture and autologous osteochondral transfer are not suitable for the treatment of these larger lesions. Fresh osteochondral allograft transplantation provides a surgical option for these challenging defects, both as a primary procedure and for salvage of prior failed treatment attempts. This article reviews the basic science, indications, technique, and evidence for osteochondral allograft transplantation in the knee.

Integration of Tissue-engineered Cartilage With Host Cartilage: An In Vitro Model

We developed a tissue-engineered biphasic cartilage bone substitute construct which has been shown to integrate with host cartilage and differs from autologous osteochondral transfer in which integration with host cartilage does not occur. (1) Develop a reproducible in vitro model to study the mechanisms regulating tissue-engineered cartilage integration with host cartilage, (2) compare the integrative properties of tissue-engineered cartilage with autologous cartilage and (3) determine if chondrocytes from the in-vitro formed cartilage migrate across the integration site. A biphasic construct was placed into host bovine osteochondral explant and cultured for up to 8 weeks (n = 6 at each time point). Autologous osteochondral implants served as controls (n = 6 at each time point). Integration was evaluated histologically, ultrastructurally, biochemically and biomechanically. Chondrocytes used to form cartilage in vitro were labeled with carboxyfluorescein diacetate which allowed evaluation of cell migration into host cartilage. Histologic assessment demonstrated that tissue-engineered cartilage integrated over time, unlike autologous osteochondral implant controls. Biochemically there was an increase in collagen content of the tissue-engineered implant over time but was well below that for native cartilage. Integration strength increased between 4 and 8 weeks as determined by a pushout test. Fluorescent cells were detected in the host cartilage up to 1.5 mm from the interface demonstrating chondrocyte migration. Tissue-engineered cartilage demonstrated improved integration over time in contrast to autologous osteochondral implants. Integration extent and strength increased with culture duration. There was chondrocyte migration from tissue-engineered cartilage to host cartilage. This in vitro integration model will allow study of the mechanism(s) regulating cartilage integration. Understanding this process will facilitate enhancement of cartilage repair strategies for the treatment of chondral injuries.

Knee Cartilage Tibio-Femoral Injuries

Summary: Articular cartilage lesions of the femoral condyles are common and have limited healing capacity. The goal of surgical management is to relieve pain and mechanical symptoms, and hopefully slow the progression of osteoarthritis. Numerous surgical procedures have been described to include chondroplasty, microfracture, autologous chondrocyte implantation, autologous osteochondral transfer, allograft osteochondral transplantation, and fragment fixation. Each technique is distinguished by number of procedures required, expense, donor-site morbidity, risks of allograft tissues, and rehabilitation requirements. To maximize the surgical outcomes, it is imperative to treat any concomitant pathology to include mechanical malalignment, ligamentous instability, and/or meniscal deficiency. Several treatment algorithms have been proposed to guide management of symptomatic, focal chondral injuries of the femoral condyles. Algorithm decisions are based on lesion location, size, patient activity level, and earlier treatment. This article reviews the treatment considerations of the various techniques and the published results and illustrative case examples.

Autogenous Osteochondral Transfer in the Femoral Head After Osteonecrosis

Osteonecrosis of the femoral head is a major problem, especially in younger patients. Most of them need a total hip replacement. This article presents a case of a successful autologous osteochondral transfer.

Current strategies for articular cartilage repair

Defects of articular cartilage that do not penetrate to the subchondral bone fail to heal spontaneously. Defects that penetrate to the subchondral bone elicit an intrinsic repair response that yields a fibrocartilaginous repair tissue which is a poor substitute for hyaline articular cartilage. Many arthroscopic repair strategies employed utilise this intrinsic repair response to induce the formation of a repair tissue within the defect. The goal, however, is to produce a repair tissue that has the same functional and mechanical properties of hyaline articular cartilage. To this end, autologous osteochondral transfer can provide symptomatic relief. This technique involves the excision of healthy cartilage plugs from 'non-load bearing' regions of the joint for implantation into the defect. Cell based transplantation methods currently involve the transplantation of expanded autologous chondrocytes to the defects to form a repair tissue. This technique again involves the excision of healthy cartilage from the joint for expansion. Current research is exploring the potential use of mesenchymal stem cells as a source for tissue engineering, as well as the combination of cells with biodegradable scaffolds. Although current repair strategies improve joint function, further research is required to prevent future degeneration of repair tissue.

Chondrocyte Death Associated with Human Femoral Osteochondral Harvest as Performed for Mosaicplasty

Autologous osteochondral transfer is an option for the treatment of articular defects. However, there are concerns about graft integration and the nature of the tissue forming the cartilage-cartilage bridge. Chondrocyte viability at graft and recipient edges is thought to be an important determinant of the quality of repair. The purpose of the present study was to evaluate early cell viability at the edges of osteochondral grafts from ex vivo human femoral condyles. Fresh human tissue was obtained from eleven knees at the time of total knee arthroplasty for the treatment of osteoarthritis. Osteochondral cylinders were harvested with use of a 4.5-mm-diameter mosaicplasty osteotome from regions of the anterolateral aspect of the femoral condyle that were macroscopically nondegenerate and histologically nonfibrillated. Plugs were assessed for marginal cell viability by means of confocal laser scanning microscopy. The diameter of the cartilaginous portion of the osteochondral plugs was a mean (and standard error of the mean) of 4.84 +/- 0.12 mm (as determined on the basis of three plugs). This value was approximately 300 microm greater than the measured internal diameter of the osteotome. There was a substantial margin of superficial zone cell death (mean thickness, 382 +/- 68.2 microm), with >99% cell viability seen more centrally (as determined on the basis of five plugs). Demiplugs were created by splitting the mosaicplasty explants with a fresh number-11 scalpel blade. The margin of superficial zone cell death at the curved edge was significantly greater than that at the site of the scalpel cut (390.3 +/- 18.8 microm compared with 34.8 +/- 3.2 microm; p = 0.0286). Similar findings were observed when the cartilage alone was breached and the bone was left intact, with the margin of superficial zone cell death being significantly greater than that obtained in association with the straight scalpel incision (268 +/- 38.9 microm compared with 41.3 +/- 13.4 microm; p = 0.0286). The margin of superficial zone cell death showed no increase during the time-period between fifteen minutes and two hours after plug harvest. A mathematical approximation of the mosaicplasty region suggested that early cell death of this magnitude affects about one third of the superficial graft area. The results of the present study suggest that mosaicplasty, while capable of transposing viable hyaline cartilage, is associated with an extensive margin of cell death that is likely to compromise lateral integration and articular reconstruction.

CHONDROCYTE DEATH ASSOCIATED WITH HUMAN FEMORAL OSTEOCHONDRAL HARVEST AS PERFORMED FOR MOSAICPLASTY

Background: Autologous osteochondral transfer is an option for the treatment of articular defects. However, there are concerns about graft integration and the nature of the tissue forming the cartilage-cartilage bridge. Chondrocyte viability at graft and recipient edges is thought to be an important determinant of the quality of repair. The purpose of the present study was to evaluate early cell viability at the edges of osteochondral grafts from ex vivo human femoral condyles. Methods: Fresh human tissue was obtained from eleven knees at the time of total knee arthroplasty for the treatment of osteoarthritis. Osteochondral cylinders were harvested with use of a 4.5-mm-diameter mosaicplasty osteotome from regions of the anterolateral aspect of the femoral condyle that were macroscopically nondegenerate and histologically nonfibrillated. Plugs were assessed for marginal cell viability by means of confocal laser scanning microscopy. Results: The diameter of the cartilaginous portion of the osteochondral plugs was a mean (and standard error of the mean) of 4.84 ± 0.12 mm (as determined on the basis of three plugs). This value was approximately 300 μm greater than the measured internal diameter of the osteotome. There was a substantial margin of superficial zone cell death (mean thickness, 382 ± 68.2 μm), with >99% cell viability seen more centrally (as determined on the basis of five plugs). Demiplugs were created by splitting the mosaicplasty explants with a fresh number-11 scalpel blade. The margin of superficial zone cell death at the curved edge was significantly greater than that at the site of the scalpel cut (390.3 ± 18.8 μm compared with 34.8 ± 3.2 μm; p = 0.0286). Similar findings were observed when the cartilage alone was breached and the bone was left intact, with the margin of superficial zone cell death being significantly greater than that obtained in association with the straight scalpel incision (268 ± 38.9 μm compared with 41.3 ± 13.4 μm; p = 0.0286). The margin of superficial zone cell death showed no increase during the time-period between fifteen minutes and two hours after plug harvest. A mathematical approximation of the mosaicplasty region suggested that early cell death of this magnitude affects about one third of the superficial graft area. Conclusions: The results of the present study suggest that mosaicplasty, while capable of transposing viable hyaline cartilage, is associated with an extensive margin of cell death that is likely to compromise lateral integration and articular reconstruction. Clinical Relevance: The data suggest that there is a need to improve the plug-harvest technique, which may improve graft-recipient healing and clinical outcomes.

Surgical dislocation of the adult hip

Surgical dislocation of the hip is rarely undertaken. The potential danger to the vascularity of the femoral head has been emphasised, but there is little information as to how this danger can be avoided. We describe a technique for operative dislocation of the hip, based on detailed anatomical studies of the blood supply. It combines aspects of approaches which have been reported previously and consists of an anterior dislocation through a posterior approach with a 'trochanteric flip' osteotomy. The external rotator muscles are not divided and the medial femoral circumflex artery is protected by the intact obturator externus. We report our experience using this approach in 213 hips over a period of seven years and include 19 patients who underwent simultaneous intertrochanteric osteotomy. The perfusion of the femoral head was verified intraoperatively and, to date, none has subsequently developed avascular necrosis. There is little morbidity associated with the technique and it allows the treatment of a variety of conditions, which may not respond well to other methods including arthroscopy. Surgical dislocation gives new insight into the pathogenesis of some hip disorders and the possibility of preserving the hip with techniques such as transplantation of cartilage.