Objective: Various tear types and patterns of meniscus injuries have been described. We record meniscus tear type and pattern in a standard manner for every knee arthroscopy in our database of more than 17,000 knee surgeries. We determined if meniscus tear type and pattern correlate with function and activity levels at least two years after partial meniscectomy.

Methods: Two hundred six (206) patients underwent partial medial meniscectomy and 117 underwent partial lateral meniscectomy by a single surgeon (average age=49 years; range, 18 to 80). At index surgery, the type and pattern of meniscus tear was recorded. Tears were designated as bucket handle/vertical longitudinal (BV), flap/radial (FR), or complex (CH) which includes horizontal cleavage tears. Patients not in neutral or near-neutral alignment and those undergoing concurrent procedures for microfracture or ACL reconstruction were excluded. Patients were followed for a minimum of two years (average=4.6 yrs) after partial meniscectomy. Patients completed questionnaires including Lysholm and Tegner scores to assess function and activity.

Results: For the medial meniscus, there was significant correlation between tear type and patient age. The BV lesion group (n=35) was significantly younger (41 years) than the FR (n=65) (50 years) and CH (n=193) (53 years) groups (p=0.01). The BV group had significantly higher Lysholm (89) scores versus FR (80) and CH (77) (p=0.04). The BV group also had higher Tegner activity levels (5.8) than FR (4.6) and CH (4.5) (p=0.04). For lateral meniscus, the BV (n=15) (40 years) and FR (n=37) (48 years) groups were significantly younger than the CH group (n=45) (56 years); p=0.03. FR patients had higher Lysholm and Tegner scores, but not significantly different. Twenty-five percent (25%) of BV medial meniscus tears required further surgery while less than 15% of other types of medial or lateral tears required further surgery. Average time to second surgery for all patients was 2.4 years, with medial being 2.6 years and lateral being 1.5 years.

Conclusions: In this series, BV medial meniscus tears had better function and activity levels at least two years post-meniscectomy, perhaps due to younger age. This group also required more reoperations during the first two years after index meniscectomy than any other group, perhaps as a result of higher activity levels. Overall, partial lateral meniscectomy patients required reoperation sooner than medial meniscectomies. Tear type did not significantly influence outcomes after lateral meniscectomy. Therefore, meniscus tear type and pattern correlated with function and activity levels for medial but not lateral > 2 years after partial meniscectomy.

Introduction: Many knee outcomes measures have recently been developed and validated. However, most of these are lengthy and too cumbersome to use in a busy sports medicine practice. The purpose of this study was to develop a one-page outcomes form that documents function, activity and patient satisfaction for collection of knee outcomes data in a format that can be analyzed easily so that a surgeon may better assess the outcomes of the therapeutic regimens used.

Methods: Validated knee questionnaires were evaluated for their length and ease of scoring. Scores were evaluated for test-retest reliability, floor and ceiling effects, criterion validity, construct validity, and responsiveness to change. In addition, the psychometric properties of a single-item patient satisfaction instrument with outcomes score were studied.

Results: The Lysholm score and Tegner activity scale are short in length and provide a validated outcomes measurement tool for several sports medicine procedures. In addition to being validated for ACL, meniscus, and chondral defects, we tested their psychometric properties in patients seeking treatment for osteoarthritis of the knee. The Tegner scale and overall Lysholm score showed acceptable test-retest (ICC = 0.87 and 0.79, respectively) reliability, floor and ceiling effects, criterion validity, construct validity, and responsiveness to change. The standard error of the Lysholm was 6.7 and the minimum detectable change at 95% confidence level (MDC95) was 16. For the Tegner score, the standard error was 0.60 and the MDC95 was 1.2. For the one-item patient satisfaction scale, there was an acceptable floor (4.3%) but a high ceiling (39.4%) effect. There was acceptable criterion validity with significant (p< 0.05) correlations between the satisfaction with surgical outcomes and the validated Group Health of America Consumer Satisfaction Survey. There was acceptable construct validity with all hypotheses demonstrating significance (p< 0.05). Acceptable responsiveness to change was found.

Conclusions: The Lysholm score, the Tegner activity scale, and a one-item patient satisfaction with outcomes scale provide a valid one-page knee outcomes measurement form. This simple form allows the collection of knee outcomes data in a busy sports medicine practice to help surgeons better assess the clinical outcomes in their patients.

Objective: Lysholm and Tegner scores have been validated to assess outcomes of meniscus surgery. We prospectively determined Lysholm scores for function and calculated Tegner index to determine percentage of pre-injury activity level regained by patients six years after partial meniscectomy alone versus placement of collagen meniscus implants (CMI, MenaflexTM). We hypothesized that in this prospective randomized multicenter clinical trial, patients who received collagen meniscus implant would have better function and would have regained more of their lost activity than patients with meniscectomy alone.

Methods: Patients 18 to 60 years old who had undergone 1 to 3 prior partial medial meniscectomies (thus deemed “chronic”) and remained symptomatic randomly received either a CMI (n=76) or another partial medial meniscectomy (control) (n=69). Lysholm and Tegner data were collected prospectively. Tegner index was calculated by subtracting preoperative Tegner scores from the longest follow-up scores and then dividing that difference by the difference of pre-injury less preoperative scores. The quotient multiplied by 100 yields a percentage that represents amount of lost activity regained as a result of therapeutic intervention. The findings were then compared to earlier analyses of the same patients.

Results: Average follow-up for both groups was 72 months (range for CMI, 24 to 88; for controls, 24 to 92). For both groups, Lysholm scores improved significantly (p=0.0001) from preoperative to 6 years postoperative, but there was no difference between treatments. Average Tegner index for CMI patients was 0.47; thus, 6 years after receiving CMI they had regained 47% of activity lost due to the inciting injury. Average Tegner index for controls was 0.22; thus, they regained 22% of lost activity. This difference was clinically and statistically significant (p=0.028). The Lysholm scores for both groups were unchanged from 2-year findings; however, Tegner index for CMI patients improved from 0.42 to 0.47, but Tegner index decreased for controls from 0.29 earlier to 0.22 at 6 years.

Conclusion: CMI (Menaflex) and partial meniscectomy both allowed chronic patients to regain function equally 6 years after index surgery. However, patients treated with CMI had significantly higher Tegner index at 6 years compared to controls, thus chronic CMI patients regained more of the activity they had lost as a result of their inciting injury. Noteworthy, CMI patients continued to gain activity from 2 to 6 years while meniscectomy only controls lost activity. These findings suggest that control patients reduced their activity levels in an attempt to maintain their function.

Purpose: Meniscus loss leads to decreased clinical function and activity levels and increases rate of knee degeneration, thus leading to additional surgeries or even knee replacement, especially in chronic patients. Chronic patients are more focused on preserving their knees and avoiding additional surgeries. The purpose of this study was to determine if replacement of lost or irreparable meniscus tissue with the Collagen Meniscus Implant (CMI) decreased the need for additional surgeries in multiply operated chronic knee patients compared to meniscectomy only. We hypothesized that patients who gained meniscus tissue with the CMI would require fewer surgeries than meniscectomy only controls through five years.

Methods: In this prospective randomized multicenter clinical trial (Level of Evidence I), patients 18 to 60 years old who had undergone one to three prior partial medial meniscectomies (PMM) and currently had clinical symptoms of meniscus pathology were randomized either to receive the CMI or have an additional PMM (control). Eighty-five CMI were implanted, but one was removed at 3 weeks after an incision wound infection, and two patients died. The remaining 82 CMI patients were compared to 66 controls over 5 years to determine survivorship. Survivorship was defined as not having an additional unplanned surgery outside the experimental protocol on the study knee.

Results: Follow-up rate at 5 years was 96%. Eight CMI patients (9.5%) and 15 control patients (22.7%) required reoperation through 5 years. Survivorship at one year was 90% for control and 95% for CMI patients, 86% for control and 95% for CMI patients at 2 years, 83% and 92% at 3 years, 79% for control patients and 91% for CMI patients at 4 years, and 74% for control patients and 89% for CMI patients at 5 years. CMI patients had a significantly higher survivorship compared to controls (p=0.04). The risk (odds) of reoperation was 2.7 times greater for controls compared to CMI patients at 5 years (95% CI=1.2 to 6.7). Furthermore, the majority of control patient reoperations occurred prior to 24 months, but only four CMI reoperations occurred during the first 24 months.

Conclusion: This study confirms that chronic patients who received the CMI required fewer additional surgeries in their multiply operated knees than PMM only controls through 5 years. The additional tissue regeneration supported by the CMI may decrease progression of degenerative changes and reduce necessity and frequency for additional surgeries. This study further confirms the importance of preserving as much meniscus tissue as possible at time of meniscus surgery, and clearly it supports potential positive benefits of regrowing or regenerating lost meniscus tissue. Our hypothesis was affirmed.

Purpose: The purpose of this study was to determine psychometric properties of the Lysholm score and Tegner activity scale as patient-administered outcomes scores for anterior cruciate ligament injuries of the knee. We hypothesized that these two outcomes measures remain valid by today’s standards twenty-five years after they were originally introduced as physician-administered outcomes instruments.

Methods: One thousand seven hundred eighty-three (1783) patients were included in this study. There were 749 females and 1034 males. Average age was 37 years (range, 18 to 77). Isolated ACL tears were documented in 593 patients, and 1190 patients had concurrent injuries including meniscus pathology and/or cartilage damage. Patients with multiple ligamentous injuries were excluded. All patients in this study were diagnosed with an ACL tear at arthroscopy. For responsiveness, scores were measured preoperatively and at a minimum of two years postoperatively. For test-retest, scores were measured at a minimum of two years postoperatively and again within four weeks of the original postoperative questionnaire. For criterion validity, patients completed the short form (SF-12^®) of the health related quality-of-life scale and the IKDC score in addition to Lysholm and Tegner instruments. For all other analyses, preoperative Lysholm score or Tegner activity levels were used.

Results: There was acceptable test-retest reliability for overall Lysholm score (ICC=0.94 [95% confidence interval=0.88 to 0.96]) and Tegner (ICC=0.82 [95% confidence interval=0.66 to 0.89]). The minimum detectable change for Lysholm was 8.9 and for Tegner was 1.4. The Lysholm score demonstrated acceptable internal consistency (Cronbach’s alpha=0.72). The Lysholm score correlated with IKDC (r=0.78) and the physical function domain of SF-12^® (r=0.43). The Tegner scale correlated with physical function domain of SF-12^® (r=0.2) and IKDC (r=0.22). Both scores had acceptable floor and ceiling effects, and all hypotheses were significant. The Lysholm score and Tegner scale both had a large overall effect size. There were no differences between isolated and combined ACL injuries.

Conclusion: After 25 years of changes in treatment of ACL injuries and postoperative rehabilitation protocols, the Lysholm knee score and Tegner activity scale continue to demonstrate acceptable psychometric parameters. The Lysholm score and Tegner scale both had acceptable test-retest reliability, construct validity, criterion validity, content validity, and responsiveness when patient-administered similar to the physician-administered results when they were originally validated. Our hypothesis was affirmed.

Prospectively, we determined amount of meniscus loss and anatomic location of Collagen Meniscus Implant (CMI) placement after partial medial meniscectomy (PMM). At 1-year relook we determined total meniscus tissue present based on surface area coverage. We correlated percent of meniscus and anatomic location of the original lesion with function and activity levels 6 years after CMI placement. We hypothesized that meniscus amount and anatomic location would influence clinical function and activity levels.

In a prospective randomized controlled multicenter clinical trial (Level of Evidence I), 114 chronic patients (1 to 3 prior PMM on the involved meniscus) 18 to 60 years old underwent partial medial meniscectomy, and then randomly one group received a CMI to fill the meniscus defect. There were 68 PMM only controls and 46 CMI patients. At index surgery, amount and anatomic location of meniscus removed and CMI placement were documented on a standard grid. Locations were categorized as posterior (A), middle (B), or anterior (C) third. A 1-year relook was done on CMI patients, and meniscus surface area coverage was measured. Patients were followed clinically for a minimum of two years and subjectively annually thereafter. Average follow-up was 69 months (range, 24 to 92). All patients completed validated questionnaires including Lysholm and Tegner scores to assess function and activity.

For CMI patients, 29 had lesions which included posterior and middle thirds (AB), and 17 had lesions involving all three zones (ABC). Lysholm scores were significantly higher in patients with AB lesions (81) compared to ABC lesions (71), p=0.046. AB lesion patients also had significantly higher Tegner index (0.70) than ABC lesion patients (0.22), thus AB patients regained more of their lost activity, p=0.049. Comparing all patients with > 60% meniscus surface area coverage, CMI patients had significantly higher Tegner index compared to controls (0.59 vs. 0.30), p=0.036. No differences between treatment groups were seen in patients with < 60% meniscus surface area coverage. When comparing 24 month to final follow-up values, controls had no change for Lysholm (p=0.13) or Tegner (p=0.39) scores, but CMI patients improved significantly over time for both Lysholm (p=0.02) and Tegner (p=0.04) scores.

Zones of meniscus involvement influenced clinical outcomes at 6 years in CMI patients. Those whose lesions extended into all three zones did worse than those with lesions in posterior and middle zones only. Patients with successful CMI procedures yielding > 60% meniscus surface area coverage were significantly better than PMM only controls for both clinical function and activity levels. Noteworthy, CMI patients continue to improve over time for clinical function and activity levels, but PMM controls do not.

Background: Bone sarcomas are the fourth most common cancer in individuals under 25 years. Limb salvage procedures are popular for the treatment of osteosarcomas as they have functional and physiological benefits over traditional amputative procedures.

Objectives: To apply disease specific measures to a group of intra-articular knee osteosarcoma patients and to evaluate structural and treatment variables predictive of the functional outcome scores.

Methods: Twenty patients (10., 10.) treated with tumour resection and endoprosthetic knee arthroplasty took part in the study. The Musculoskeletal Tumour Society (MSTS) rating scale and the Toronto Extremity Salvage Score (TESS) were used to assess impairment and disability along with a musculoskeletal eveluation.

Results: Impairment was recorded as 83.33% and disability was recorded as 86%. Task difficulty was shown to increase for activities requiring large knee flexion angles, presumably due to increased patellofemoral forces. Correlations were observed between the MSTS score and (a) knee flexion range of motion, (b) muscle removal, and also between the TESS and (a) time from surgery, (b) quadriceps strength and (c) knee flexion range of motion. ANOVA revealed no significant differences in impairment (P = 0.962) or disability (P = 0.411) between the differing types of prostheses.

Conclusions: Clinicians and therapists should emphases restoration of post surgical range of motion and strength in order to enhance functional recovery.

INTRODUCTION: Loss of meniscus tissue leads to decreased clinical function and activity levels. However, no report has quantified the amount of meniscus tissue removed at meniscectomy and correlated meniscus tissue loss with clinical symptoms, function, and activity. We determined, prospectively, the amount of tissue loss at time of partial medial meniscectomy and then correlate extent of meniscus loss with clinical symptoms, function, and activity levels 2 years following the index meniscectomy.

METHODS: In a randomized controlled investigational device clinical trial (Level of Evidence I), 149 patients 18 to 60 years old underwent partial medial meniscectomy and served as controls. There were 81 acute (no prior meniscus surgery) and 68 chronic (1 to 3 prior partial meniscectomies on the involved meniscus) patients. At index surgery, size of the meniscus defect was measured using specially designed instruments, and percent of meniscus loss was calculated based on actual measurements. Patients were followed clinically for a minimum of 2 years after meniscectomy. At each follow-up, every patient completed questionnaires including Lysholm and Tegner scores to assess function and activity. Amount of meniscus tissue at index surgery was correlated with the individual domains of the Lysholm scale. Tegner index was calculated to determine the amount of lost activity regained 2 years after surgical intervention.

RESULTS: Two-year data were available for 127 patients (85% follow-up). There was a significant correlation between the amount of meniscus tissue remaining following the index meniscectomy and 2-year Lysholm domains of squatting (r=0.281, p=0.001), stair-climbing (r=0.251, p=0.004), and swelling (r=0.261, p=0.003). In particular, it is noteworthy that patients who had > 50% of their meniscus remaining had significantly better function than patients who had < 50% meniscus remaining. Patients who had worse or no improvement in pain symptoms at 2 years averaged 42% meniscus remaining, while patients who had improved pain scores had on average 51% meniscus remaining. Tegner index for patients with < 50% meniscus remaining averaged 24%, and for patients with > 50% meniscus remaining averaged 52% (p=0.017); hence, a greater amount of meniscus tissue remaining allowed patients to regain significantly more of their lost activity.

CONCLUSIONS: There is a significant correlation between the amount of meniscus tissue removed at men-iscectomy and clinical symptoms, function, and activity 2 years after surgery. This study confirms the importance of preserving as much meniscus tissue as possible at the time of meniscus repair or meniscectomy as well as the potential positive benefits of regrowing or replacing lost meniscus tissue in order to minimize clinical symptoms that may be suggestive of early degenerative changes.

The aim of this study was to retrospectively assess the long term results of the surgical excision of a series of proximal tibio-fibula joint ganglions. They are uncommon tumours in this position (prevalence < 1%) and mimic more sinister pathology creating diagnostic difficulty. From the Queensland Orthopaedic Oncology Database, twelve patients were identified who had presented with proximal tibio-fibular joint cysts between 1991 and 2004 and proceeded to surgery. There were four males and eight females with an average age of 44 years (18–75). One patient had bilateral cysts but elected to only have one side resected. The side distribution was equal. All patients presented with a swelling and ten with pain. Two patients presented with a common peroneal nerve palsy. All patients obtained a marginal excision and histology confirmed a ganglion cyst. Patients were seen at clinic or contacted by phone to assess continued symptoms or recurrence. At mean long term follow up of 49 months (8–168), eight patients had had no recurrence. One patient postoperatively had a transient common peroneal nerve palsy. Of the four patients who had had a recurrence, one patient’s surgery is planned and another patient at 5 months post surgery is symptom free following further resection. The two remaining patients have required re-resection but have presented with further recurrence within 1 year. The common peroneal nerve palsies resolved between 6–12 weeks post surgery. A number of case reports record neurological involvement by direct epineurial involvement but this behaviour was not observed in our series. Review of the literature shows no larger series than ours. We conclude that cysts arising in this region commonly present with pain, swelling and neurology. Recurrence rate is high (33%) and further marginal resection is unlikely to lead to cure. More aggressive surgery such as joint excision or arthrodesis may then be necessary.

Introduction: Incomplete removal of calcified cartilage appears to be associated with suboptimal repair tissue attachment. Furthermore, histologic evaluation of arthroscopically debrided chondral lesions demonstrated that removal of calcified cartilage was not obvious using standard arthroscopic equipment. The purpose of this study was to compare chondral healing with and without removal of calcified cartilage in experimentally created chondral defects.

Methods: Twelve mature horses underwent bilateral arthroscopy of the femorotibial joints. A 1cm2 chondral lesion was made on the weight bearing surface of both medial femoral condyles. Randomly, in each horse one lesion had complete removal of the calcified cartilage layer (CCL) using curettes, and the CCL was left intact on the contralateral side. All defects were subjected to subchondral bone microfracture. At 12 months, all horses were euthanized and all femorotibial joints were harvested. MR imaging was performed in a 1.5 Tesla clinical MRI scanner. Analysis of variance was to analyze data.

Results: Gross and histomorphometric observations confirmed significantly (p< 0.05) better repair tissue at 12 months after surgery in defects where the CCL had been removed compared to defects where the CCL remained intact. MRI results revealed subjectively thinner and more incomplete repair tissue filling defects where the CCL remained intact compared to when it had been removed.

Conclusions: Based on gross, MRI and histologic findings, this study suggests that care should be taken in debridement of clinical cartilage lesions to assure complete removal of calcified cartilage.

Summary: Removal of the calcified cartilage layer significantly improves the healing of chondral defects.

Introduction: The Lysholm knee score and the Tegner activity scale are frequently used to assess outcome following treatment of meniscus pathology. The purpose of this study was to determine the psychometric properties of the Lysholm knee score and Tegner activity level for meniscus injuries 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 within 3 subsets of patients. Group A contained patients with only meniscus pathology at surgery (no ligament pathology or chondral surface pathology) (n=191). Group B consisted of patients at least 2 years from surgery for meniscus pathology, who completed a follow-up form and then completed a retest with 4 weeks of the primary questionnaire (n=122). Group C consisted of patients with meniscus pathology with other intraarticular pathology (n=477).

Results: There were acceptable (intraclass correlation coefficient > 0.70) test-retest reliability for the overall Lysholm score and the Tegner activity scale. (Group B). There were acceptable floor and ceiling effects for the Tegner scale (floor: 8.1%; ceiling: 2.5%) and the overall Lysholm score (floor: 0%; ceiling: 0.4%) (Group A and C). There were unacceptable (> 30%) ceiling effects for the Lysholm domains of limp, instability, support, and locking. There was acceptable criterion validity, with significant (P< 0.05) correlations between the Tegner activity scale and the physical score of the SF-12 and between the overall Lysholm score and the physical score of the SF-12(Group C). There was acceptable construct validity for the Tegner activity scale and Lysholm score, with all hypotheses demonstrating significance (P< 0.05) (Group A). There was acceptable responsiveness to change for the Tegner activity scale (Group A effect size=0.61; standardized response mean=0.60; Group C effect size=0.84; standardized response mean=0.70) and the Lysholm score(Group A effect size=1.2; standardized response mean=0.97; Group C effect size =1.2; standardized response mean =1.13).

Discussion: The use of outcome instruments whose psychometric properties have been vigorously established is essential. The Lysholm knee score demonstrated overall acceptable psychometric performance for outcomes assessment of meniscus injuries of the knee, although some domains demonstrated suboptimal performance. The Tegner activity scale demonstrated overall acceptable psychometric performance for outcomes assessment of meniscus injuries of the knee, however, it demonstrated only moderate effect size. Psychometric testing of other condition-specific knee instruments in patients with meniscus pathologies of the knee would be helpful to allow for comparison of properties.

Introduction: Studies have shown that the Kellgren-Lawrence (K-L) score can differentiate the severity of osteoarthritis (OA). However, this grading system has not been compared with intraoperative assessment. The purpose of this study was to correlate the arthroscopic findings of knees with severe OA with their Kellgren-Lawrence grade.

Methods: Tibiofemoral knee OA was graded according to the K-L scale in 89 knees presenting for arthroscopic treatment for knee OA. The study group consisted of 55 males and 34 females with an average age of 55 (range 37 to 88) years. Each radiograph was examined by two orthopaedic surgeons, and arthroscopic data were collected prospectively.

Results: Radiographic grading yielded five knees with Grade 2 K-L, 47 with Grade 3 K-L, and 37 with Grade 4 K-L. At arthroscopy, ipsilateral tibial/femoral lesions were noted in 66 knees, including 17 knees with tibial/femoral lesions of both compartments. Meniscus pathology was present in 78 knees including 37 knees with both medial and lateral pathology. When comparing knees with radiographic K-L grades of 3 and 4, the following was noted: more males had Grade 4 K-L (p=0.001); knees with Grade 4 K-L were more likely to exhibit Outerbridge Grade III or IV tibial/femoral lesions on 3 or 4 surfaces (p=0.001); Grade 4 K-L knees had significantly more ipsilateral tibial/femoral lesions (p=0.000); and finally, Grade 4 K-L knees were more likely to contain meniscus pathology (p=0.032).

Conclusion: Grade 4 Kellgren-Lawrence scores correlated with more severe chondral degeneration and meniscus pathology. The Kellgren-Lawrence scale can differentiate between moderate and severe osteoarthritis.

Aims:We conducted 5 to 6-year follow up on 8 patients who had reconstruction of one injured medial meniscus with a collagen meniscus implant (CMI). We hypothesized that these patients would have signiþcant clinical improvement over preoperative status.Methods: Eight patients underwent CMI placement to reconstruct the medial meniscus of one knee. Patients were followed for 2 years clinically, with imaging, relook arthroscopy, and biopsy then all patients returned 5.8 years (5.5 to 6.3 years) after CMI placement. Patients underwent clinical, radiographic, MRI, and arthroscopic examinations. Pain, Lysholm, Tegner and self-assessment scores were compared to scores at CMI surgery. Results: Lysholm scores improved signiþcantly from 75 at CMI surgery to 88 at þnal follow up, and Tegner activity scores improved signiþcantly from 3 to 6. Self-assessment improved signiþcantly from 2.4 to 1.9. Pain scores improved from 23 to 11. Imaging studies conþrmed no further chondral surface degeneration. The maturing new tissue became indistinguishable from native meniscus tissue. One-year relook arthroscopy revealed 77% defect þlling with new meniscus-like tissue, and 5 to 6-year relooks showed 69% defect þlling. The new tissue was stable and mostly unchanged since the initial relook. Conclusions: The meniscus-like tissue that developed after placement of the CMI has survived more than þve years and functioned similar to native meniscus to provide signiþcantly improved clinical outcomes compared to preoperative status in this study group.