Biologically Regulated Marrow Stimulation by Blocking TGF-ß1 With Losartan Oral Administration Results in Hyaline-like Cartilage Repair: A Rabbit Osteochondral Defect Model.

BACKGROUND: Microfracture or bone marrow stimulation (BMS) is often the first choice for clinical treatment of cartilage injuries; however, fibrocartilage, not pure hyaline cartilage, has been reported because of the development of fibrosis in the repair tissue. Transforming growth factor ß1 (TGF-ß1), which can promote fibrosis, can be inhibited by losartan and potentially be used to reduce fibrocartilage. HYPOTHESIS: Blocking TGF-ß1 would improve cartilage healing in a rabbit knee BMS model via decreasing the amount of fibrocartilage and increasing hyaline-like cartilage formation. STUDY DESIGN: Controlled laboratory study. METHODS: An osteochondral defect was made in the patellar groove of 48 New Zealand White rabbits. The rabbits were divided into 3 groups: a defect group (defect only), a BMS group (osteochondral defect + BMS), and a BMS + losartan group (osteochondral defect + BMS + losartan). For the rabbits in the BMS + losartan group, losartan was administrated orally from the day after surgery through the day of euthanasia. Rabbits were sacrificed 6 or 12 weeks postoperatively. Macroscopic appearance, microcomputed tomography, histological assessment, and TGF-ß1 signaling pathway were evaluated at 6 and 12 weeks postoperatively. RESULTS: The macroscopic assessment of the repair revealed that the BMS + losartan group was superior to the other groups tested. Microcomputed tomography showed superior healing of the bony defect in the BMS + losartan group in comparison with the other groups. Histologically, fibrosis in the repair tissue of the BMS + losartan group was significantly reduced when compared with the other groups. Results obtained with the modified O'Driscoll International Cartilage Repair Society grading system yielded significantly superior scores in the BMS + losartan group as compared with both the defect group and the BMS group (F value: 15.8, P < .001, P = .012, respectively). TGF-ß1 signaling and TGF-ß-activated kinase 1 of the BMS + losartan group were significantly suppressed in the synovial tissues. CONCLUSION: By blocking TGF-ß1 with losartan, the repair cartilage tissue after BMS was superior to the other groups and consisted primarily of hyaline cartilage. These results should be easily translated to the clinic because losartan is a Food and Drug Administration-approved drug and it can be combined with the BMS technique for optimal repair of chondral defects. CLINICAL RELEVANCE: Biologically regulated marrow stimulation by blocking TGF-ß1 (oral intake of losartan) provides superior repair via decreasing fibrocartilage formation and resulting in hyaline-like cartilage as compared with outcomes from BMS only.

Meniscus suture repair: minimum 10-year outcomes in patients younger than 40 years compared with patients 40 and older.

BACKGROUND: Few studies have compared outcomes after meniscus suture repair in patients younger than 40 years versus patients 40 years and older. PURPOSE: To document failure rates and long-term outcomes after meniscus suture repair by a single surgeon, using the inside-out technique, at a minimum 10-year follow-up in patients younger than 40 years versus those 40 years and older. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This study included all patients 18 years or older who underwent meniscus suture repair with the inside-out technique by a single surgeon between January 1992 and December 2003. Patients were divided into 2 cohorts according to age: <40 years (cohort 1) and ≥40 years (cohort 2). If patients underwent subsequent knee surgery, all subsequent reports, whether performed by the original treating surgeon or by a different surgeon elsewhere, were reviewed by 2 independent reviewers not involved in the primary care of the patients. Reviewers classified surgeries as failures if the subsequent surgery treated the same area of the meniscus as repaired in the index surgery. Patients completed a subjective questionnaire at minimum of 10 years after arthroscopy. Outcomes measures included Lysholm, Tegner, and patient satisfaction with outcome. All data were collected prospectively. RESULTS: The surgeon performed 339 meniscus repairs between 1992 and 2003. The study included 181 knees in 178 patients, who had a mean age of 33 years (range, 18-70 years). Cohort 1 contained 136 knees; 16 patients (12%) were lost to follow-up and 47 (35%) underwent a subsequent knee arthroscopy. Cohort 2 contained 45 knees; 2 patients (4.4%) were lost to follow-up, 3 patients had a total knee arthroplasty, and 12 patients (28%) underwent a subsequent knee arthroscopy. In cohort 1, the meniscus repair failure rate was 5.5% (6/110), and in cohort 2 it was 5.3% (2/38) (P = .927). There was no significant difference in failure rate based on which meniscus was repaired (P = .257), concomitant anterior cruciate ligament (ACL) reconstruction (P = .092), or microfracture (P = .674). Average follow-up time for cohort 1 was 16.1 years (range, 10.0-21.9 years), with 82% follow-up (n = 73/89); average follow-up time for cohort 2 was 16.2 years (range, 10.1-21.0 years), with 93% follow-up (n = 28/30). There were no significant differences in outcomes scores after meniscus suture repair based on age cohort or meniscus side, presence of an ACL tear, or concomitant microfracture procedure. CONCLUSION: Meniscus repair failure rate was not different in patients who were younger than 40 years versus those who were 40 years or older at time of meniscus index surgery. Patients who underwent meniscus suture repair had high function and high patient satisfaction at an average of 16 years after meniscus suture repair, and no differences were seen based on age.

Resorbable collagen scaffolds for the treatment of meniscus defects: a systematic review.

PURPOSE: The purpose of this study was to evaluate the clinical and structural outcomes after resorbable collagen meniscus scaffold implantation through a systematic review of the published literature. METHODS: A systematic search of both the PubMed and Embase databases was undertaken to identify all studies that reported clinical and/or structural outcomes after resorbable collagen meniscus scaffold implantation for the treatment of defects involving either the medial or lateral meniscus. Extracted data included study characteristics; surgical methods and rehabilitation protocols; objective outcomes; and preoperative and postoperative subjective outcome scores including Lysholm, Tegner, International Knee Documentation Committee, and visual analog scale scores. RESULTS: Thirteen studies were included in this review. There were 10 Level IV studies, 2 Level II studies, and 1 Level I study with follow-up intervals ranging from 3 months to 12.5 years. With a few exceptions, the study designs used in each study generally followed those which had been previously performed. Substantial differences in rehabilitation protocols and concomitant procedures were noted that may have had an effect on overall clinical outcomes. Objective findings were mostly consistent and typically showed minimal degenerative changes on postoperative radiographs, decreased signal intensity of the scaffold over time on magnetic resonance imaging, the presence of meniscus-like tissue at second-look arthroscopy, and good integration of new tissue as evidenced by histologic analysis of biopsy specimens. Most studies reported satisfactory clinical outcomes, and most patients showed substantial improvements in comparison with mean preoperative baseline values. CONCLUSIONS: On the basis of this systematic review, implantation of resorbable collagen scaffolds for the treatment of meniscus defects provides satisfactory clinical and structural outcomes in most cases. There is evidence that collagen meniscus scaffold implantation provides superior clinical outcomes when compared with partial meniscectomy alone. LEVEL OF EVIDENCE: Level IV, systematic review of Level I, II, and IV studies.

Outcomes following healing response in older, active patients: a primary anterior cruciate ligament repair technique.

The purpose of this study was to document outcomes following the healing response procedure for treatment of complete, proximal anterior cruciate ligament (ACL) tears in a mature, active population. Healing response is an all-arthroscopic procedure that preserves the native ACL and makes use of an arthroscopic awl with a 45-degree angle to make holes in the femoral attachment of the ACL and in the body of the ACL. Patients were included in this IRB-approved study if they were > or =40 years old, had a complete proximal ACL tear, and who had healing response within 6 weeks of initial injury. In this study 48 patients (35 females, 13 males) with an average age of 51 years (range: 41 to 68 years) underwent the healing response procedure. Of these four female patients (8.9%) required subsequent ACL reconstruction. Mean time to ACL reconstruction was 34.5 months (range, 14.3 to 61.2 months). Of the 44, 41 patients (93%) had minimum of 2-year follow-up at an average of 7.6 years (range, 2.2 to 13.4 years). Average preoperative Lysholm score was 54 (range, 10 to 82) and improved to an average of 90 postoperatively (p = 0.001). Median Tegner activity scale at follow-up was 5 (range, 2 to 9). Median patient satisfaction was 10 (range, 4 to 10). Higher patient satisfaction was correlated with increased Lysholm score at follow-up (rho = 0.39, p = 0.02). Tegner activity scale was associated with postoperative Lysholm score (rho = 0.35, p = 0.04). This study demonstrates the effectiveness of the healing response procedure to allow patients to return to high levels of recreational activity and to restore knee function to normal levels. In a select group of mature patients with acute proximal ACL tears, the healing response procedure is an effective treatment technique.

Biological enhancement of meniscus repair and replacement.

When a meniscus injury occurs, it is generally accepted that preserving the meniscus is important for life-long joint preservation. Traditional suture repair of the meniscus has good results; however, the healing potential of meniscus tissue remains as a biological challenge because it is not a completely vascularized structure. For this reason, investigators have continued to search for adjuncts to improve clinical results. Mechanical adjuncts, local factor enhancement, scaffolds, gene therapy, and cell therapy have all been examined as options for improvement of biology and structure. This study reviews the basic science and clinical application of these modalities and provides an assessment of techniques on the horizon.

Effects of Platelet-Rich Plasma Composition on Anabolic and Catabolic Activities in Equine Cartilage and Meniscal Explants.

OBJECTIVE: To evaluate the effects of single- and double-spin preparations of platelet-rich plasma (PRP) on anabolic and catabolic activities of cartilage and meniscal explants in vitro. METHODS: Single- and double-spin PRP was prepared using laboratory processing or commercial kits. The cellular contents were quantified, and each PRP was mixed in equal quantities with cell culture medium and added to cartilage or meniscus explant cultures, with or without interleukin 1 ß (IL-1ß). Extracellular matrix synthesis was quantified over 24 hours via (35)S-sulfate and (3)H-proline incorporation, while gene expression of catabolic enzymes was evaluated using real-time PCR. RESULTS: The platelet concentration in single-spin laboratory PRP was 59% higher than blood. Platelet and white blood cell concentrations in single-spin laboratory and kit PRP were not significantly different, while the double-spin kit resulted in approximately 2.5-fold higher platelet and approximately 400-fold higher white blood cell concentrations. In cartilage cultures without IL-1ß, radiolabel incorporation in single-spin PRP cultures was significantly higher than in double-spin cultures. Similar results were obtained for (35)S-sulfate incorporation in meniscus cultures without IL-1ß. In IL-1ß, radiolabel incorporation was largely similar among all PRPs. After 24 hours of culture, ADAMTS-4 gene expression in cartilage was lowest for single-spin PRP, while expression in the double-spin kit was not significantly different from double-spin laboratory PRP in which platelets were concentrated 6-fold. CONCLUSIONS: This study suggests that single-spin PRP preparations may be the most advantageous for intra-articular applications and that double-spin systems should be considered with caution.

Evaluation of intra-articular mesenchymal stem cells to augment healing of microfractured chondral defects.

PURPOSE: This study evaluated intra-articular injection of bone marrow-derived mesenchymal stem cells (BMSCs) to augment healing with microfracture compared with microfracture alone. METHODS: Ten horses (aged 2.5 to 5 years) had 1-cm2 defects arthroscopically created on both medial femoral condyles of the stifle joint (analogous to the human knee). Defects were debrided to subchondral bone followed by microfracture. One month later, 1 randomly selected medial femorotibial joint in each horse received an intra-articular injection of either 20 × 10(6) BMSCs with 22 mg of hyaluronan or 22 mg of hyaluronan alone. Horses were confined for 4 months, with hand walking commencing at 2 weeks and then increasing in duration and intensity. At 4 months, horses were subjected to strenuous treadmill exercise simulating race training until completion of the study at 12 months. Horses underwent musculoskeletal and radiographic examinations bimonthly and second-look arthroscopy at 6 months. Horses were euthanized 12 months after the defects were made, and the affected joints underwent magnetic resonance imaging and gross, histologic, histomorphometric, immunohistochemical, and biochemical examinations. RESULTS: Although there was no evidence of any clinically significant improvement in the joints injected with BMSCs, arthroscopic and gross evaluation confirmed a significant increase in repair tissue firmness and a trend for better overall repair tissue quality (cumulative score of all arthroscopic and gross grading criteria) in BMSC-treated joints. Immunohistochemical analysis showed significantly greater levels of aggrecan in repair tissue treated with BMSC injection. There were no other significant treatment effects. CONCLUSIONS: Although there was no significant difference clinically or histologically in the 2 groups, this study confirms that intra-articular BMSCs enhance cartilage repair quality with increased aggrecan content and tissue firmness. CLINICAL RELEVANCE: Clinical use of BMSCs in conjunction with microfracture of cartilage defects may be potentially beneficial.

Rehabilitation following microfracture for chondral injury in the knee.

Full-thickness chondral defects in the knee are common, and these articular cartilage lesions may present in various clinical settings and at different ages. Articular cartilage defects that extend full thickness to subchondral bone rarely - by providing a suitable environment for new tissue formation and takes advantage of the body's own healing potential. Proper surgical technique and rehabilitation improve the success rate of the microfracture procedure. The goals are to alleviate the pain and disability that can result from chondral lesions and restore joint conformity, thereby preventing late degenerative changes in the joint.

Microfracture: Its History and Experience of the Developing Surgeon.

Development and implementation of the microfracture technique began in the early 1980s. The surgical goal was to produce "microfractures" in the subchondral bone perpendicular to the surface and to be able to reach all areas of the joint with the instruments. The microfracture technique has been demonstrated to be an effective arthroscopic treatment for full-thickness chondral lesions and joints with degenerative lesions. This technique is cost effective, technically not complicated, has an extremely low rate of associated patient morbidity, and leaves options for further treatment. Patient compliance with rehabilitation, knee alignment, and the depth of the cartilage rim surrounding the lesion are a few of the factors that can affect the outcomes following microfracture.

The reliability, validity, and responsiveness of the Lysholm score and Tegner activity scale for anterior cruciate ligament injuries of the knee: 25 years later.

BACKGROUND: In 1982, the Lysholm score was first published as a physician-administered score in the American Journal of Sports Medicine. The Tegner activity scale was published in 1985. HYPOTHESIS: The Lysholm and Tegner scores are valid as patient-administered scores and responsive at early time points after treatment of anterior cruciate ligament tears. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 1. METHODS: All patients were treated for an anterior cruciate ligament tear. For responsiveness, the Lysholm score (n = 1075) and Tegner activity level (n = 505) were measured preoperatively and 6, 9, 12, and 24 months postoperatively. For test-retest (n = 50), scores were measured at 2 years postoperatively and again within 4 weeks by questionnaire. For criterion validity (n = 170), patients completed the Short Form-12 and the International Knee Documentation Committee score in addition to Lysholm and Tegner instruments. For all other analyses, preoperative Lysholm score (n = 1783) or Tegner activity levels (n = 687) were collected. RESULTS: There was acceptable test-retest reliability for both the Lysholm (intraclass correlation coefficient = 0.9) and Tegner (intraclass correlation coefficient = 0.8) scores. The minimum detectable change for Lysholm was 8.9 and for Tegner was 1. The Lysholm demonstrated acceptable internal consistency. The Lysholm correlated with the International Knee Documentation Committee (r = .8) and the Short Form-12 (r = .4), and Tegner correlated with the Short Form-12 (r = .2). Both scores had acceptable floor and ceiling effects and all hypotheses were significant. The Lysholm and Tegner were responsive to change at each of the time points. CONCLUSION: After 25 years of changes in treatment of anterior cruciate ligament injuries, the Lysholm knee score and the Tegner activity scale demonstrated acceptable psychometric parameters as patient-administered scores and showed acceptable responsiveness to be used in early return to function after anterior cruciate ligament treatment.

Comparison of the collagen meniscus implant with partial meniscectomy. A prospective randomized trial.

BACKGROUND: Loss of meniscal tissue leads to increased pain and decreased clinical function and activity levels. We hypothesized that patients receiving a collagen meniscus implant would have better clinical outcomes than patients treated with partial medial meniscectomy alone. METHODS: Three hundred and eleven patients with an irreparable injury of the medial meniscus or a previous partial medial meniscectomy, treated by a total of twenty-six surgeon-investigators at sixteen sites, were enrolled in the study. There were two study arms, one consisting of 157 patients who had had no prior surgery on the involved meniscus (the "acute" arm of the study) and one consisting of 154 patients who had had one, two, or three prior meniscal surgical procedures (the "chronic" arm). Patients were randomized either to receive the collagen meniscus implant or to serve as a control subject treated with a partial meniscectomy only. Patients underwent frequent clinical follow-up examinations over two years and completed validated outcomes questionnaires over seven years. The patients who had received a collagen meniscus implant were required by protocol to have second-look arthroscopy at one year to determine the amount of new tissue growth and to perform a biopsy to assess tissue quality. Reoperation and survival rates were determined. RESULTS: In the acute group, seventy-five patients received a collagen meniscus implant and eighty-two were controls. In the chronic group, eighty-five patients received the implant and sixty-nine were controls. The mean duration of follow-up was fifty-nine months (range, sixteen to ninety-two months). The 141 repeat arthroscopies done at one year showed that the collagen meniscus implants had resulted in significantly (p = 0.001) increased meniscal tissue compared with that seen after the original index partial meniscectomy. The implant supported meniscus-like matrix production and integration as it was assimilated and resorbed. In the chronic group, the patients who had received an implant regained significantly more of their lost activity than did the controls (p = 0.02) and they underwent significantly fewer non-protocol reoperations (p = 0.04). No differences were detected between the two treatment groups in the acute arm of the study. CONCLUSIONS: New biomechanically competent meniscus-like tissue forms after placement of a collagen meniscus implant, and use of the implant appears safe. The collagen meniscus implant supports new tissue ingrowth that appears to be adequate to enhance meniscal function as evidenced by improved clinical outcomes in patients with a chronic meniscal injury. The collagen meniscus implant has the utility to be used to replace irreparable or lost meniscal tissue in patients with a chronic meniscal injury. The implant was not found to have any benefit for patients with an acute injury.

Reliability, validity, and responsiveness of the IKDC score for meniscus injuries of the knee.

PURPOSE: The purpose of this study was to determine the psychometric properties of the International Knee Documentation Committee (IKDC) score for meniscus injuries of the knee. METHODS: Test-retest reliability, content validity, construct validity, and responsiveness to change were determined for the IKDC score. Knees were excluded if they had ligament pathology or a chondral defect greater than Outerbridge grade 2. All patients had meniscus pathology requiring treatment. The study comprised 4 subsets of patients. Group A consisted of 31 patients who completed an IKDC form at least 2 years after surgery for meniscus pathology and were then retested within 4 weeks of the primary questionnaire. Group B contained 264 patients with preoperative IKDC scores that were used for construct and content validity. Group C contained 50 patients who had a preoperative IKDC score and completed a short form 12 survey. Group D contained 100 patients with preoperative and postoperative IKDC scores used to measure responsiveness. RESULTS: The overall IKDC score showed acceptable test-retest reliability with an interclass correlation of 0.95. There were acceptable floor and ceiling effects. All constructs tested showed significant differences. These included lower IKDC score with the following: lower activity level, difficulty with activities of daily living, difficulty with sports, abnormal knee function, and complex/degenerative meniscus tears. Responsiveness to change showed a large effect size (2.11) and a large response mean (1.5) for the overall score. The SE of the measurement was 3.19, and the minimum detectable change was 8.8 points. CONCLUSIONS: The overall IKDC score showed overall acceptable psychometric performance for outcome measures of meniscus injuries of the knee. LEVEL OF EVIDENCE: Level III, testing of previously developed diagnostic criteria in nonconsecutive patients.

Effects of calcified cartilage on healing of chondral defects treated with microfracture in horses.

BACKGROUND: Microfracture of full-thickness articular defects has been shown to significantly enhance the amount of repair tissue. However, there is a suggestion that leaving calcified cartilage inhibits this repair response. HYPOTHESIS: Removal of the calcified cartilage with retention of subchondral bone enhances the amount of attachment of the repair tissue compared with retention of the calcified cartilage layer. STUDY DESIGN: Controlled laboratory study. METHODS: There were 1-cm(2) articular cartilage defects made in 12 skeletally mature horses on the axial weightbearing portion of both medial femoral condyles. Using a custom measuring device and direct arthroscopic observation of the subchondral bone beneath the calcified cartilage layer, the authors removed the calcified cartilage from 1 defect of each horse. The repair was assessed with arthroscopy, clinical examination, radiographic and magnetic resonance imaging examinations, biopsy at 4 months, gross and histopathologic examinations at 12 months, as well as mRNA and immunohistochemical evaluations. RESULTS: Removal of calcified cartilage with retention of the subchondral bone plate increased the overall repair tissue as assessed by arthroscopic (4 months) and gross evaluation (12 months). An increase in the level of the subchondral bone was also observed with removal of the calcified cartilage layer. The clinical pain, radiographic examinations, magnetic resonance imaging evaluations, histologic character, matrix proteins, or mRNA expression do not appear to differ based on level of defect debridement. CLINICAL RELEVANCE: Removal of the calcified cartilage layer appears to provide optimal amount and attachment of repair tissue. Therefore, close arthroscopic visualization is recommended for debridement of clinical lesions to ensure removal of the calcified cartilage layer.

Reliability, validity, and responsiveness of the Lysholm knee score and Tegner activity scale for patients with meniscal injury of the knee.

BACKGROUND: A torn meniscus is one of the most common indications for knee surgery. The purpose of this study was to determine the psychometric properties of the Lysholm knee score and the Tegner activity scale when used for patients with a meniscal injury of the knee. METHODS: Test-retest reliability, content validity, criterion validity, construct validity, and responsiveness to change were determined for the Lysholm score and the Tegner activity scale. Test-retest reliability was measured in a group of 122 patients at least two years after they had undergone surgery for a meniscal lesion. This group completed a follow-up form and then completed it again within four weeks. The other tests were performed in a group of 191 patients who had only a meniscal lesion at the time of the surgery and a group of 477 patients who had a meniscal lesion and other intra-articular lesions. RESULTS: The overall Lysholm score showed acceptable test-retest reliability, floor and ceiling effects, criterion validity, construct validity, and responsiveness to change. There were unacceptable ceiling effects (>30%) for the Lysholm domains of limp, instability, support, and locking. The Tegner activity scale showed acceptable test-retest reliability, floor and ceiling effects, criterion validity, construct validity, and responsiveness to change. CONCLUSIONS: Overall, the Lysholm knee score and the Tegner activity scale demonstrated acceptable psychometric performances as outcome measures for patients with a meniscal injury of the knee. Some domains of the Lysholm score showed suboptimal performance, and the Tegner scale had only a moderate effect size. Psychometric testing of other condition-specific knee instruments for patients with a meniscal lesion of the knee would be helpful to allow comparison of the properties of the various knee instruments.

Microfracture of the hip in athletes.

Most studies addressing treatment of chondral injuries have involved the knee. Various techniques have been used in the knee. Microfracture has shown excellent results in the knee. Chondral injuries of the hip are common in athletes with labral tears and femoroacetabular impingement. The microfracture technique is now being used in the hip joint. Indications include full-thickness cartilage loss or unstable flap on a weight-bearing surface. An important contraindication is the patients unwillingness to follow the postoperative protocol and rehabilitation plan. The microfracture technique in the hip is similar to that in the knee. Postoperatively, patients use a continuous passive motion and are flat foot (20 lbs.) weightbearing for 8 weeks. Early results following microfracture in the hip have been encouraging.

A minimally invasive technique ("healing response") to treat proximal ACL injuries in skeletally immature athletes.

This study documents outcomes of athletically active, skeletally immature patients with proximal anterior cruciate ligament (ACL) tears treated with a non-reconstructive technique to promote healing ("healing response"). Between 1992 and 1998, 13 skeletally immature athletes with proximal ACL tears underwent a healing response procedure. Patients with previous ACL injury, other concurrent ligament pathology, and/or complete mid-substance ACL tears were excluded. Average preoperative KT-1000 arthrometer manual maximum difference for all patients was 5 mm (range: 3-10 mm). Preoperatively, all patients had a 1+ or 2+ pivot shift, and all patients reported knee function as abnormal or severely abnormal. Patients were followed prospectively with clinical examinations, KT-1000 testing, and subjective questionnaires. Three (23%) patients had a re-injury 30 to 55 months after the healing response and underwent subsequent ACL reconstruction. Subjective follow-up on the remaining 10 patients at an average of 69 months (range: 26-113 months) postoperatively indicated no patients experienced pain or giving way, and all considered their knee function normal. Average Lysholm score was 96, Tegner score was 8.5 (range: 7-10), and patient satisfaction at follow-up was 9.9 (1=very dissatisfied and 10=very satisfied). Clinical examination at least one year postoperatively was performed on 7 of 10 patients at 35 months (range: 12-63 months). Five patients had a negative pivot shift and 2 had a 1+ pivot shift. KT-1000 measurements improved to 2 mm (range: 0-3 mm). In the athletically active, skeletally immature patient, the healing response procedure can restore stability and knee function, with proper patient selection. In this study group, patients were very satisfied with the procedure and returned to a high level of sports and activities.

Healing of a surgically created partial detachment of the posterior cruciate ligament using marrow stimulation: an experimental study in dogs.

The inability of intra-articular (cruciate) ligaments to generate a substantive reparative response may preclude the primary surgical repair of such lesions. A marrow stimulation technique that provides access to a fibrin scaffold, cytokines, and mesenchymal stem cells has been shown to be successful in generating a repair response in articular cartilage. We hypothesized that a similar approach may be effective in initiating and supporting a healing response in cruciate ligament injuries. The ability to treat cruciate ligament injuries by primary repair may have significant advantages over the more extensive reconstructive procedures currently advocated. Bilateral subtotal (75% of width) lacerations were made in the proximal aspect of the posterior cruciate ligament (PCL) in 10 adult mongrel dogs. A marrow stimulation technique in which small holes were made through the femoral origin of the PCL into the marrow cavity immediately adjacent to the lesion was performed in one limb. The contralateral limb served as the non-stimulated control. Twelve weeks after surgery the extent of healing and the histological character of the repair tissue in both groups were compared. Marrow stimulation resulted in a statistically significant (P<.05) improvement in the healing of subtotal lacerations made in the PCL. The marrow-stimulated repair tissue was more cellular and had a more organized extracellular matrix than the repair tissue in the non-stimulated group. Our hypothesis was confirmed. Marrow stimulation can induce a "healing response" in intra-articular (cruciate) ligaments. This technique may have clinical applications in primary surgical repair of these structures.

Tissue-engineered collagen meniscus implants: 5- to 6-year feasibility study results.

PURPOSE: In this feasibility study, a 5- to 6-year clinical follow-up evaluation was conducted on 8 patients who had undergone reconstruction of 1 injured medial meniscus with a tissue-engineered collagen meniscus implant. The hypothesis was that these patients would show significant clinical improvement over their preoperative status and would have maintained their status determined at the 2-year follow-up evaluation. TYPE OF STUDY: Prospective longitudinal feasibility study follow-up evaluation. METHODS: Eight patients underwent arthroscopic placement of a collagen meniscus implant by a single surgeon to reconstruct and restore the irreparably damaged medial meniscus of 1 knee. All patients returned for clinical, radiographic, magnetic resonance imaging, and arthroscopic examinations an average of 5.8 years (range, 5.5-6.3 y) after collagen meniscus implant placement. RESULTS: Lysholm scores improved significantly (P = .045) from 75 preoperatively to 88 at most recent follow-up evaluation. Average Tegner activity scores improved significantly (P = .001) from 3 to 6. Patient self-assessment improved significantly (P = .046) from 2.4 to 1.9 (1 = normal, 4 = severely abnormal). Pain scores improved from 23 to 11 (0 = no pain, 100 = worst pain). Imaging studies confirmed that the chondral surfaces of the medial compartment had not degenerated further since the placement of the implant 5.8 years earlier. Relook arthroscopy with direct measurement of the newly generated tissue revealed 69% defect filling. Histologic assessment of tissue biopsy specimens from 3 patients showed the presence of fibrocartilage with a uniform extracellular matrix. CONCLUSIONS: The meniscus-like tissue that developed after collagen meniscus implant placement has maintained its structure and functioned without negative effects for more than 5 years. The hypothesis was affirmed that these patients were improved significantly compared with their preoperative status and unchanged compared with 2-year evaluations. LEVEL OF EVIDENCE: Level IV.

Patient satisfaction and outcome after microfracture of the degenerative knee.

Satisfaction and functional outcome was measured in 81 patients who were treated arthroscopically with microfracture for isolated degenerative lesions of the knee. Average patient age was 49 years (range: 40-70 years) and average degenerative lesion measured 229.5 mm2 (range: 25-2000 mm2). Patients were evaluated at average 2.6-year follow-up (range: 2-5 years). All subjective parameters measured (pain, swelling, limping, walking, stairs, sport level, and activities of daily living) demonstrated significant improvement over preoperative status (P<.003). Lysholm score improved from 53.8 to 83.1 (P<.001), and mean Tegner Activity Scale score improved from 2.9 to 4.5 (P<.05). No significant association was noted between Lysholm improvement and gender or age. Significant improvement in mean Lysholm score was noted for lesions in all three knee compartments. Thirteen patients required repeat arthroscopy within 5 years of initial microfracture for lysis of adhesions. Five patients required revision microfracture to a previously treated lesion or total knee arthroplasty at an average of 23 months (range: 5-36 months) from the initial microfracture. Microfracture is an efficacious surgical option for the treatment of degenerative chondral lesions of the knee. The modest rate of failure and need for arthroscopic lysis of adhesions reflects the challenge of joint-sparing arthroscopic surgery in the degenerative knee.

Outcomes of microfracture for traumatic chondral defects of the knee: average 11-year follow-up.

PURPOSE: In this study, we measured functional outcomes of patients treated arthroscopically with microfracture for full-thickness traumatic defects of the knee. TYPE OF STUDY: A case series of patients with 7 to 17 years' follow-up. METHODS: Between 1981 and 1991, a total of 72 patients (75 knees) met the following inclusion criteria: (1) traumatic full-thickness chondral defect, (2) no meniscus or ligament injury, and (3) age 45 years and younger (range, 13 to 45 years). Seventy-one knees (95%) were available for final follow-up (range, 7 to 17 years). All patients completed self-administered questionnaires preoperatively and postoperatively. RESULTS: The following results were significant at the P <.05 level. Significant improvement was recorded for both Lysholm (scale 1 to 100; preoperative, 59; final follow-up, 89) and Tegner (1 to 10; preoperative, 3; final follow-up, 6) scores. At final follow-up, the SF-36 and WOMAC scores showed good to excellent results. At 7 years after surgery, 80% of the patients rated themselves as "improved." Multivariate analysis revealed that age was a predictor of functional improvement. CONCLUSIONS: Over the 7- to 17-year follow-up period (average, 11.3 years), patients 45 years and younger who underwent the microfracture procedure for full-thickness chondral defects, without associated meniscus or ligament pathology, showed statistically significant improvement in function and indicated that they had less pain.