Fresh osteochondral allografts for post-traumatic knee defects: Surgical technique

Cartilage issues in football-today's problems and tomorrow's solutions

Articular cartilage injury is prevalent in football players and results from chronic joint stress or acute traumatic injuries. Articular cartilage injury can often result in progressive painful impairment of joint function and limit sports participation. Management of articular cartilage injury in athletes aims to return the player to competition, and requires effective and durable joint surface restoration that resembles normal hyaline articular cartilage that can withstand the high joint stresses of football. Existing articular cartilage repair techniques can return the athlete with articular cartilage injury to high-impact sports, but treatment does not produce normal articular cartilage, and this limits the success rate and durability of current cartilage repair in athletes. Novel scientific concepts and treatment techniques that apply modern tissue engineering technologies promise further advancement in the treatment of these challenging injuries in the high demand athletic population. We review the current knowledge of cartilage injury pathophysiology, epidemiology and aetiology, and outline existing management algorithms, developing treatment options and future strategies to manage articular cartilage injuries in football players.

Surgical restoration/repair of articular cartilage injuries in athletes

Articular cartilage injuries of the knee are an increasingly common source of pain and dysfunction, particularly in the athletic population. In the athlete, untreated articular cartilage defects can represent a career threatening injury and create a significant obstacle in returning to full athletic participation. The markedly limited healing potential of articular cartilage often leads to continued deterioration and progressive functional limitations. Numerous studies have shown that full thickness articular cartilage lesions are frequently encountered at the time of arthroscopy, particularly associated with athletic injury. A variety of surgical treatment options exist, including debridement, microfracture, osteochondral autograft, osteochondral allograft, and autologous chondrocyte implantation. Each technique has advantages and limitations for restoring articular cartilage function, and emerging technology continues to improve the results of treatment. Our article provides an evidence-based review on the etiology and prevalence of articular cartilage injuries in athletes, along with the principles and techniques available for restoring articular cartilage function following injury.

Surgical treatment for osteochondritis dissecans of the capitellum

Context:

Osteochondritis dissecans (OCD) of the capitellum is most often seen in adolescents who participate in sports that involve repetitive loading of the elbow. Unstable defects typically require surgical intervention that involves fragment fixation, debridement, or reconstruction with an osteochondral autograft transfer. Optimum surgical management of unstable defects remains controversial.

Type of Study:

Clinical review.

Evidence Acquisition:

Relevant articles published after 1992 were identified using MEDLINE, the EMBASE database, and the Cochrane Library.

Results:

Both debridement and osteochondral autograft transfer for treatment of capitellar OCD lesions result in good short- and midterm outcomes with a high rate of return to sports. Larger defects involving more than 50% of the articular surface or involving the lateral margin of the capitellum may have worse outcomes after debridement and may be better treated with fragment fixation or osteochondral autograft transfer.

Conclusions:

High-level evidence is lacking to determine the superiority of debridement or osteochondral autograft transfer for the treatment of capitellar OCD lesions. A prospective longitudinal multicenter study, using validated outcome measures, that enrolls a large number of patients is needed to establish optimal treatment for unstable capitellar OCD lesions.

Articular Cartilage Injury in Athletes

Articular cartilage lesions in the athletic population are observed with increasing frequency and, due to limited intrinsic healing capacity, can lead to progressive pain and functional limitation over time. If left untreated, isolated cartilage lesions can lead to progressive chondropenia or global cartilage loss over time. A chondropenia curve is described to help predict the outcome of cartilage injury based on different lesion and patient characteristics. Nutriceuticals and chondroprotective agents are being investigated as tools to slow the development of chondropenia. Several operative techniques have been described for articular cartilage repair or replacement and, more recently, cartilage regeneration. Rehabilitation guidelines are being developed to meet the needs of these new techniques. Next-generation techniques are currently evaluated to optimize articular cartilage repair biology and to provide a repair cartilage tissue that can withstand the high mechanical loads experienced by the athlete with consistent long-term durability.

Treatment of articular cartilage lesions of the knee

Treatment of articular cartilage lesions in the knee remains a challenge for the practising orthopaedic surgeon. A wide range of options are currently practised, ranging from conservative measures through various types of operations and, recently, use of growth factors and emerging gene therapy techniques. The end result of these methods is usually a fibrous repair tissue (fibrocartilage), which lacks the biomechanical characteristics of hyaline cartilage that are necessary to withstand the compressive forces distributed across the knee. The fibrocartilage generally deteriorates over time, resulting in a return of the original symptoms and occasionally reported progression to osteoarthritis. Our purpose in this study was to review the aetiology, pathogenesis and treatment options for articular cartilage lesions of the knee. At present, autologous cell therapies, growth factor techniques and biomaterials offer more promising avenues of research to find clinical answers.

Reversal of suppressed metabolism in prolonged cold preserved cartilage

Chondrocytes in cold preserved cartilage are metabolically suppressed. The goal of this study was to address this metabolic suppression and seek ways to reverse it. Specifically, we examined the roles of rewarming protocols and nitric oxide (NO) in this metabolic suppression. Bovine and canine full-thickness articular cartilage explants were cultured under various temperature conditions, and NO production, proteoglycan (PG) synthesis, and cell viability were measured. Nitric oxide was shown to be negatively correlated with PG synthesis following abrupt rewarming of cold preserved osteochondral allografts. Gradual rewarming of the allograft tissue decreased NO production with higher PG synthesis. Inhibition of nitric oxide synthases (NOS) led to a decrease in NO production and a concomitant increase in PG synthesis. We were able to partially reverse metabolic suppression of cold preserved osteochondral allograft material with gradual rewarming and decrease NO production with NOS inhibition. Chondrocytes in cold preserved allograft material may be metabolically suppressed predisposing the graft to failure in vivo. Minimizing this loss of metabolic function by gradual graft rewarming and decreasing NO production by NOS inhibition at the time of graft implantation may have implications on graft survival in vivo.

Osteoarticular autograft and allograft transplantation of the knee: 3 year follow-up

Between 1998 and 2001, a total of 48 patients underwent autologous or allograft osteoarticular transplantation with a minimum follow-up of 24 months. Nineteen patients underwent concomitant procedures. Average patient age was 46 years. Graft area averaged 4.8 cm2 (range, 0.2-21.6 cm(2)). Grafts implanted included 24 autografts, 12 refrigerated allografts, and 12 frozen allografts. Average follow-up was 37.1 months (range, 24-63 months). Postoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Knee Society Score (KSS), and pain scores improved significantly. Age <35 years and male gender was associated with a positive outcome. There was no significant difference in improvement between autograft and allograft groups. Nine patients, considered failures, underwent total knee arthroplasty and data analysis. No significant relationship was noted for any variable. Eighty-one percent of grafts are still functioning >3 years after transplantation.

Biologic approaches to articular cartilage surgery: future trends

The treatment of unicompartmental osteoarthritis and focal chondral pathologic conditions in the knee in active aging athletes has captured the interest of patients, clinicians, basic scientists, and medical industry researchers. Most would agree that a biologic solution to treating hyaline cartilage injuries and degeneration would be optimal over prosthetic joint arthroplasty. Articular cartilage resurfacing techniques and biologic surgical methods continue to evolve and have gained more acceptance in orthopedic practice. A consensus exists for the ultimate goal of achieving a more predictable and durable result after surgical tissue repair or regeneration. Numerous promising approaches are now on the horizon and although the final word is far from in, the integration of many of the anticipated advances in molecular medicine, biomedical engineering, polymer chemistry, cell biology, and clinical orthopedics contributes to an exciting and rapidly evolving field. This article reviews the current concepts of the biologic approach to articular cartilage pathologic conditions and discusses future trends and novel technologies.

Treatment Options for Articular Cartilage Defects of the Knee

The treatment of symptomatic articular cartilage defects of the knee has evolved tremendously in the past decade. Previously, there were limited treatment options available to patients who suffered from either partial-thickness or full-thickness cartilage lesions. Because articular cartilage has a limited capacity for healing, patients were often treated symptomatically until they became candidates for osteotomy or total joint replacement. Recently, both reparative and restorative procedures have been developed to address this significant source of morbidity in young active patients. Microfracture is a reparative technique that induces a healing response to occur in an area of articular cartilage damage. Osteochondral autografts and allografts in addition to autologous chondrocyte implantation are restorative techniques aimed at recreating a more normal articular surface. Both types of procedures have been developed to alleviate the symptoms associated with focal chondral defects, as well as limit their potential to progress to a diffuse degenerative arthritis. Treatment can vary depending on both cartilage defect and patient factors. This article summarizes the various treatment options that have recently become available.

Surgical management of cartilage defects in athletes

The synovial joints provide a unique environment in which to carry out their critical mechanical function. The complex architecture of the articular cartilage normally provides painless motion throughout a variety of activities. Fluids secreted by cells in the superficial layers of the articular cartilage as well as in the synovium provide an almost frictionless articulation. The synovium also helps to maintain the aseptic environment found within the joint. The cartilage and fluid provide critical protection to the underlying bone. If any of these structures are damaged, or lose their efficiency, the ensuing cascade of damage inflicted on the joint can lead to catastrophic failure.

Cartilage restoration, part 2: techniques, outcomes, and future directions

In part 1 of this 2-part Current Concepts article, the authors reviewed the basic science of normal articular and meniscal cartilage and its response to injury. They reviewed the historical perspectives and basic science behind these various methods and presented a rationale for patient evaluation, treatment selection, and timing. In part 2, the authors review the specific indications for the treatment of chondral injuries and describe the techniques and outcomes of the various treatment options, including palliative, reparative, and restorative procedures. In addition, they will examine specific complex clinical scenarios emphasizing treatment options of comorbid conditions including ligament instability, meniscal deficiency, and malalignment. A limited review of the application of these techniques in joints other than the knee will also be presented. A conceptual algorithm is developed to assist in clinical decision making.

Chondrocyte viability in refrigerated osteochondral allografts used for transplantation within the knee

PURPOSE

To evaluate cell viability and matrix characteristics of refrigerated osteochondral allografts implanted up to 44 days after harvest.

METHODS

Sixteen refrigerated allografts underwent histologic and ultrastructural examination and fluorescence excitation analysis prior to implantation. The average size of the graft implanted was 6.2 cm(2) (+/-3.4 cm(2)). Refrigerated allografts averaged 30 days (range, 17 to 44 days) from donor expiration to implantation. Nine specimens underwent cell viability testing. The percent viability of refrigerated allografts prior to implantation averaged 67%.

RESULTS

No significant correlations were noted between histologic score, electron microscopy score, matrix staining percent (MSP) score, and viability. When time to implantation was assessed, an inverse correlation was noted with MSP score (r =.539) (P < 0.05), indicating less matrix staining in grafts refrigerated longer after harvest.

CONCLUSION

The current data indicate that refrigerated osteochondral allografts can be maintained for up to 44 days with average chondrocyte viability of 67%.

Modified osteochondral autograft implantation for full- thickness articular cartilage lesions

Full-thickness articular cartilage defects have been difficult to treat in patients with nonarthritic knees. A procedure is described to treat articular cartilage full-thickness lesions. Graft sites are chosen after appropriate treatment of the base of a grade IV lesion. Articular cartilage and bone are replaced into the graft site, promoting mesenchymal stem cell growth and cartilaginous coverage of the defect. Pathology, postoperative protocol, and some postoperative arthroscopic illustrations are included. This technique is simple and is associated with minimal donor-site morbidity.

Articular cartilage injuries

The acute and repetitive impact and torsional joint loading that occurs during participation in sports can damage articular surfaces causing pain, joint dysfunction, and effusions. In some instances, this articular surface damage leads to progressive joint degeneration. Three classes of chondral and osteochondral injuries can be identified based on the type of tissue damage and the repair response: (1) damage to the joint surface that does not cause visible mechanical disruption of the articular surface, but does cause chondral damage and may cause subchondral bone injury; (2) mechanical disruption of the articular surface limited to articular cartilage; and (3) mechanical disruption of articular cartilage and subchondral bone. In most instances, joints can repair damage that does not disrupt the articular surface if they are protected from additional injury. Mechanical disruption of articular cartilage stimulates chondrocyte synthetic activity, but it rarely results in repair of the injury. Disruption of subchondral bone stimulates chondral and bony repair, but it rarely restores an articular surface that duplicates the biologic and mechanical properties of normal articular cartilage. In selected patients, surgeons have used operative treatments including penetrating subchondral bone, soft tissue grafts, and cell transplants and osteochondral autografts and allografts to restore articular surfaces after chondral injuries. Experimental studies indicate that use of artificial matrices and growth factors also may promote formation of a new joint surface. However, an operative treatment of an articular surface injury that will benefit patients must not just provide a new joint surface, it must produce better long-term joint function than would be expected if the injury was left untreated or treated by irrigation and debridement alone. Therefore, before selecting a treatment for a patient with an articular cartilage injury, the surgeon should define the type of injury and understand its likely natural history.

Biologic resurfacing of the patella: current status

The techniques of biologic resurfacing of the patella, like other joint surfaces, are still evolving. Currently none of them is free from criticism. In this regard it is our hope that progress in the basic science will offer in the near future new and more optimistic therapeutic possibilities (i.e., the restoration of a reparative cartilage that is structurally and functionally comparable to the native one). The greater expectancies come perhaps from the present experimental investigations about the combined use of tissue-engineered implants embedded with staminal cells and growth factors. Many problems remain to be solved, however, before reliable applicability in humans. From a general point of view, stem cells obtained from various sources (e.g., adult bone marrow, umbilical cord) offer the same finalities as the embryonic stem cells, without the ethical obstacles related to the latter. Therefore, it may be that restoration of part or all of the articular surface of a joint will be possible by way of these mesenchymal progenitors that have the ability to differentiate into the chondrogenic and osteogenic lines, which is required for the restoration of the various layers of a normal articular cartilage and subchondral bone.

Update on advanced surgical techniques in the treatment of traumatic focal articular cartilage lesions in the knee

Considerable interest has been developed over the past several years in expanding the treatment of symptomatic femoral condylar articular cartilage lesions in active patients. Multiple surgical techniques have been reported and evolving technologies, equipment and approaches continue to expand. The purpose of this paper is to review the presentation of focal articular cartilage lesions including treatment indications, current surgical options and postoperative protocols emphasizing advanced techniques used to preserve or restore hyaline cartilage tissue. The various surgical options are discussed and the advantages and disadvantages are reviewed and highlighted in a clinical practice guideline algorithm.

Autologous chondrocyte implantation of the knee: multicenter experience and minimum 3-year follow-up

OBJECTIVE

To determine clinical outcome and graft survivorship in patients undergoing autologous chondrocyte implantation (ACI) for the repair of chondral defects of the knee.

DESIGN

Prospective cohort study.

SETTING

19 centers in the United States.

PATIENTS

50 patients (37 males, 13 females). Mean age was 36 years (range: 19-53). Defects were grade III or IV with a mean size of 4.2 cm 2. All patients had a minimum of 36 months postoperative follow-up.

MAIN OUTCOME MEASUREMENTS

Clinician and patient evaluation based on the modified Cincinnati Knee Rating System. Graft failure was defined as replacement or removal of the graft due to mechanical symptoms or pain.

RESULTS

Clinician and patient evaluation indicated median improvements of 4 and 5 points, respectively, at 36 months following ACI (p < 0.001). Previous treatment with marrow stimulation techniques and size of defect did not impact the results with ACI. The most common adverse events reported were adhesions and arthrofibrosis and hypertrophic changes. Three patients had graft failure and required reimplantation or treatment with alternative cartilage repair techniques. Kaplan-Meier estimated freedom from graft failure was 94% at 36 months postoperatively (95% CI = 88-100%).

CONCLUSIONS

These results of this study indicate excellent graft survivorship using ACI as well as substantial improvement in functional outcome.

Arthroscopic osteochondral autograft transplantation for chondral lesion of the tibial plateau of the knee

Arthroscopic osteochondral autograft transplantation is often used to treat chondral/osteochondral lesions of the femoral condyle of the knee. However, arthroscopic autologous osteochondral grafting to the tibial plateau has not been reported. We report the surgical technique and the clinical course of a patient who underwent engraftment by this method. A 26-year-old man developed symptoms of pain and catching in his knee. Arthroscopy revealed a deep chondral lesion, 10 x 15 mm in size, down to the subchondral bone on the posterocentral area of the lateral tibial plateau. The injured cartilage was debrided using a curette and an abrader until normal healthy cartilage bordered the debrided defect. An osteochondral plug, 10 mm in diameter and 20 mm long, the chondral surface of which was orientated 25 degrees obliquely, was harvested from the most peripheral and proximal part of the lateral patellar groove. A bony hole was created in the center of the defect through the tibia using a core reamer. The osteochondral plug was inserted from the tibial window through the bony hole. To enhance the stability of the osteochondral fragment, bioactive ceramic fillers were used to fill the space below the plug. A second-look arthroscopy 10 months after surgery showed that the grafted osteochondral plug was well adapted and integrated into the surrounding cartilage on the lateral tibial plateau.

Mesenchymal stem cells: building blocks for molecular medicine in the 21st century

Mesenchymal stem sells (MSCs) are present in a variety of tissues during human development, and in adults they are prevalent in bone marrow. From that readily available source, MSCs can be isolated, expanded in culture, and stimulated to differentiate into bone, cartilage, muscle, marrow stroma, tendon, fat and a variety of other connective tissues. Because large numbers of MSCs can be generated in culture, tissue-engineered constructs principally composed of these cells could be re-introduced into the in vivo setting. This approach is now being explored to regenerate tissues that the body cannot naturally repair or regenerate when challenged. Moreover, MSCs can be transduced with retroviral and other vectors and are, thus, potential candidates to deliver somatic gene therapies for local or systemic pathologies. Untapped applications include both diagnostic and prognostic uses of MSCs and their descendents in healthcare management. Finally, by understanding the complex, multistep and multifactorial differentiation pathway from MSC to functional tissues, it might be possible to manipulate MSCs directly in vivo to cue the formation of elaborate, composite tissues in situ.

Treatment algorithm for osteochondral injuries of the knee

The treatment of osteochondral fractures and OCD lesions in the knee is controversial. Many new procedures and techniques have been developed recently to address osteochondral lesions, indicating that no single procedure is accepted universally. Our treatment algorithm is based on the age of the patient, skeletal maturity, and the presence of adequate subchondral bone attached to the chondral lesion. Most nondisplaced lesions in the patient with open physes will heal with conservative treatment. The onset of skeletal maturity indicates a need for a more aggressive treatment approach. If adequate cortical bone is attached to the fragment, drilling of stable lesions, or drilling with fixation of unstable or loose fragments is appropriate. Autologous bone graft can be necessary to stimulate healing and properly reconstruct the subchondral bony contour. For failed fixation attempts or lesions not amenable to fixation, each treating surgeon must be proficient and comfortable with an articular surface reconstruction technique. The goal for the reconstructive procedure, to produce a smooth gliding articular surface of hyaline or hyaline-like cartilage, is possible using current techniques including mosaicplasty, osteochondral allograft transplantation, and autologous chondrocyte transplantation. Débridement, drilling, microfracture, and abrasion chondroplasty have been shown to result in fibrocartilage with inferior mechanical properties when compared with hyaline cartilage. No long-term studies have been published, however, to confirm the benefits of replacing osteochondral defects with hyaline cartilage rather than fibrocartilage. Although the results of many reconstructive procedures are quite encouraging with early follow up, the ultimate goal is to prevent long-term degenerative arthritis. Only well-designed prospective studies with long-term follow up will determine the adequacy of these procedures in reaching the ultimate goal. This treatment algorithm is based on the senior author's (WGC) experience with the complex dilemma of osteochondral lesions of the knee.

Cartilage repair with autogenic perichondrium cell and polylactic acid grafts

The repair of articular cartilage injuries remains a challenge, with many of the current therapeutic strategies based on the grafting or recruitment of chondrogenic tissues or cells. This 1-year study compared the repair of a 3.7-mm diameter by 3-mm deep osteochondral defect in the medial femoral condyle of 24 New Zealand White rabbits; the defect was obtained using an autogenic perichondrium cell polylactic acid composite graft with a contralateral control in which the osteochondral defect remained empty. To elucidate the effect of host immune responses on the repair process after perichondrium cell transplantation, the results of the autogenic perichondrium cell polylactic acid graft group were compared with those obtained in the authors' previous 1-year study of allogenic perichondrium cell polylactic acid composite grafts implanted in a similar model. One year after surgery, the repair site underwent gross inspection and histologic, histomorphometric, biochemical, and biomechanical analyses. The autogenic perichondrium cell polylactic acid graft group (92%) and the control group in which the osteochondral defect remained empty (88%) resulted in a high percentage of grossly acceptable repairs. The autogenic grafts appeared to augment the intrinsic healing capacity of the animals (as compared with the animals in the No Implant Group). The autogenic perichondrium cell polylactic and grafts improved the histologic appearance and percentage of Type II collagen of the cartilaginous repair tissue. Compared with allogenic grafts, the autogenic grafts had better reconstitution of the subchondral bone. However, the results of this experimental model suggest a suboptimal concentration of glycosaminoglycans in the neocartilage matrix, a depressed surface of the repair tissue, a histologic appearance that was not equivalent to that of normal articular cartilage, and reduced biomechanical properties for the repair tissue. The future application of growth factors to this model may yield a treatment that can be applied in the clinical arena.

Surgical alternatives for treatment of articular cartilage lesions

Articular cartilage injuries in the knee are common; fortunately, full-thickness articular cartilage defects constitute only a small portion of this group. These lesions may be incidentally encountered during ligament or meniscal surgery, having been silent or asymptomatic for an unknown period of time. However, when they are large and symptomatic, the surgeon may choose from a wide array of techniques available for treatment. The relatively small number of natural history studies regarding full-thickness articular surface lesions complicates the decision-making process. Accurate evaluation and classification of the anatomic defect aids in the development of a clinical algorithm for treatment. Surgical techniques are either reparative or restorative in nature. Reparative techniques fall short of complete reestablishment of the articular cartilage; however, the resultant repairs may remain quite functional for varying periods of time. Restorative techniques attempt to reestablish the native articular surface. To date, no peer-reviewed, prospective, randomized, controlled studies of operative versus nonoperative treatment for full-thickness articular cartilage lesions have been published. Even though the long-term results of surgical treatment for full-thickness articular surface lesions remain unknown, the early results are encouraging.

Evaluating methods of restoring cartilaginous articular surfaces

Surgeons and scientists have developed various approaches to restoring cartilaginous articular surfaces with the intention of relieving pain and improving mobility for people with traumatic or degenerative damage to their synovial joints. These approaches can be divided into two categories: methods intended to stimulate formation of new cartilaginous tissue and transplantation of osteochondral allografts or autografts. Experimental studies have shown that multiple variations of these approaches can restore some form of cartilaginous articular surface, but formation or transplantation of cartilaginous tissue in an animal model does not prove that a given method has the potential to relieve joint symptoms or improve joint function in humans. The effort to restore cartilaginous articular surfaces has reached the point that investigators should now evaluate the experimental results of methods intended to restore cartilaginous articular surfaces in ways that will identify the most promising approaches to the solution of clinical problems. Important issues concerning the experimental models include the types of articular surface defects studied, the age of the animal, and differences in articular cartilage among species. Important considerations in assessing the outcome of procedures designed to restore an articular surface include the overall function of the animal or patient, the function of the joint, the structure of the joint, and the structure, composition, and mechanical properties of the new tissue. This approach to evaluating methods of restoring a cartilaginous articular surface assumes that the goal of any of these methods is to provide sustained improved joint function and decreased joint symptoms in people with traumatic or degenerative joint damage, and that tissues that differ from normal articular cartilage may achieve this goal.

Osteochondral mosaicplasty for the treatment of focal chondral and osteochondral lesions of the knee and talus in the athlete. Rationale, indications, techniques, and results

New techniques for articular cartilage transplantation have become available recently for traumatic chondral injuries. Applications to the athlete have generated considerable interest in the sports medicine community. The autogenous osteochondral grafting mosaicplasty has been used to treat these injuries in the athlete population for the past six years. The rationale, indications, operative technique, results, and limitations of mosaicplasty in the athlete are presented and discussed.