Effects of abrasion therapy on tears in the avascular region of sheep menisci

This study was designed to test the hypothesis that abrasion of the parameniscal synovium aids healing of a stable tear in the avascular region of the meniscus in a sheep model. In six sheep, a 5-7-mm longitudinal full-thickness tear was made in the avascular inner half of the anterior part of the lateral meniscus. The parameniscal synovium was abraded superiorly and inferiorly from the meniscus periphery to the lesion. Three animals in a control group received identical meniscal tears but no abrasion treatment. A harness prevented weight bearing and maintained the knee fully flexed after surgery. Twelve weeks after the operation, no healing was seen in any tears. Histologic examination revealed in both groups increased numbers of dividing chondrocytes on either side of the tear. In the test group, several layers of fibroblasts, which appeared in two menisci to derive from the upper meniscal surface, were seen covering both cut surfaces of the tear. It is concluded that the distance from the periphery to the defect is too far for abrasion therapy to stimulate sufficient cellular ingrowth to facilitate repair of tears in the avascular region of the meniscus.     

Laser subtotal meniscectomy in rabbits

This study investigates the healing potential of the peripheral rim of rabbit meniscus following laser subtotal meniscectomy. Thirty animals were operated with 23 bilateral meniscectomies and 7 sham controls. When sacrificed at intervals up to 6 months, the harvested peripheral rims demonstrated a devitalized layer of fibrocartilage averaging 17 micron in thickness, indicating an extremely superficial thermal effect of the laser energy utilizing power densities of 20 to 38 W. Viable chondrocytes and minimal alteration of collagen fibril structure and orientation were noted within 20 to 50 micron of the meniscus free margin. By 2 weeks, a proliferation of vascular buds near the free margin of the meniscus was observed with an increase in ground substance production and chondrocyte population. By 10 weeks, the free margin was completely sealed and was composed of logically oriented collagen fibers and only slightly increased numbers of chondrocytes. It was concluded that the healing potential of rabbit meniscus is unimpaired following laser resection of the central margin, and that the repair process is mediated by a proliferation of chondrocytes, supported in part by neovascularity within the substance of the meniscus.     

Editorial Commentary: Discovery: Progenitor Cells and Endothelial Cells Are Found in the White-White Zone of the Meniscus,But This Does Not Mean That These Tears Heal or Should Be Repaired

More than 35 years ago, the concept of vascular zones of the meniscus was introduced. It has been shown that blood supply is limited to the peripheral 25% of the lateral and 30% of the medial meniscus. This obviously has repercussions with regard to the healing potential of meniscus tears, whether repaired or not. In general, tears that extend into the white-white zone, such as flaps, cleavage tears, and radial tears, are deemed irreparable. However, several recent reports have suggested that radial tears in the white-white zone, when repaired, heal and have good clinical outcomes. Now progenitor mesenchymal cells have been identified in the white-white zones, confirming the potential of the meniscus to heal. However, blood supply was demonstrated only by indirect signs such as the presence of endothelial cells and the presence of endothelial surface markers.     

Application of laser Doppler technology to meniscal injuries

It has been recognized for many years that the vascular supply to the meniscus has been extremely important in the potential for healing of a repaired meniscus. Early experimental work confirmed that meniscal defects that communicated with the peripheral vascular network would heal if repaired. However, those tears that did not communicate with the vascular bed would not heal even if repaired. Unfortunately, there has been no clinically applicable technique for evaluating blood flow in the torn meniscus. Experimental procedures using laser Doppler flowmetry have shown this to be a precise and simple tool for the evaluation of meniscal blood flow. Applications of this technique in the clinical situation show great promise in enabling the surgeon to make a decision to repair or remove the torn meniscus based on the blood flow in the remaining vascular bed.     

Healing potential of experimental meniscal tears in the rabbit. Preliminary results

This study assessed the healing potential of longitudinal or transverse incisions in the peripheral, central, and inner rim regions of rabbit medial menisci. Longitudinal and transverse incisions were made in 48 male New Zealand white rabbits. The incisions were either repaired with sutures or left open. The effect of joint motion on repair was also evaluated. In one group, longitudinal incisions were made in the peripheral, central, and inner rim regions of the meniscus. Some of these incisions were sutured, whereas others were not repaired. In another group, transverse incisions were made in the meniscus, extending from the inner rim to the middle of the meniscus or to the peripheral attachment (radial tear). Again, the lesions were left open or repaired. The effect of joint motion on healing was assessed by immobilizing several knees from each group with Kirschner wires temporarily for ten weeks. Suture of the meniscus incision did not substantially affect the rate of healing. When the healing rates of menisci at the periphery, body, and rim were compared, incisions at the periphery healed significantly better than incisions at the meniscal body and central rim regions. K-wire immobilization did not substantially affect the rate of healing. The difference in healing with regard to the type of incision, either longitudinal or transverse, was not statistically significant.     

Arthroscopic review of meniscal repair: assessment of healing parameters

The purpose of this study was to demonstrate what can be learned by repeat arthroscopy of meniscal repairs with regard to documenting healing, determining reasons for failure to heal, and discovering the fate of nonabsorbable suture material. The study involved 14 patients with 16 repairs who had repeat arthroscopy an average of 7.5 months after repair. Nonabsorbable suture was used in 14 of the repairs. Eleven repairs were done arthroscopically, and five were open. Charts and videotapes of both procedures were reviewed. Results showed 56% of repairs had healed, 25% had partially healed, and 13% had not healed. This is unusually slanted toward bad results for meniscal repair because the knees were usually rearthroscoped due to continued or recurrent problems. Most of the approximately 200 original patients were not symptomatic enough to warrant or submit to rearthroscopy. No damage to articular surfaces was found due to use of nonabsorbable sutures. These sutures become completely or partially incorporated into the meniscus. Meniscal repairs at risk for healing problems were set apart by an analysis of those cases with healing problems, including repairs of multiple longitudinal tears, tears greater than 40 mm in length, and tears in unstable knees. It should be emphasized that these conclusions only suggest a trend. Numbers are too few for statistical significance.     

Arthroscopic meniscal repair: analysis of treatment failures

The rationale for meniscal repair is based on the importance of the meniscus in overall knee function and stability as well as the inferior results seen with meniscectomy. The high success rate usually seen with arthroscopic meniscal repair has made it the treatment of choice for peripheral meniscal tears. This study reviewed the records of patients who have failed meniscal repair surgery to gain greater understanding of the factors that may predispose a patient to a failed outcome. From 1987 to 2002, three hundred meniscal repairs were performed (203 medial and 97 lateral). Thirty-seven patients had failed meniscal repairs. Records were available for 33 (89%) patients. The mean patient age was 25 years (range: 13-48 years) at the time of meniscal injury. The average initial tear size was 2.7 cm with a mean rim width of 2.3 mm. Eighty-eight percent occurred in ACL tears. The average time interval from initial repair to the recurrence of symptoms was 34 months. Patients who were older at the time of meniscal repair failed significantly later than those patients who were younger at the time of repair. With age stratification, those patients who were aged > or =29 years at time of meniscal repair failed at an average of 23 months. In contrast, patients who were aged > or =30 years at the time of repair failed at an average of 53 months. Larger initial tears failed significantly sooner than smaller tears. Initial tears with larger rim widths demonstrated a trend toward shorter time to failure. Patients who underwent combined ligament reconstruction with meniscal repair failed at an average of 37 months. Deficient ACLs that were treated with isolated meniscal repairs (ACL intact) failed at an average of 16 months.     

The surgical approach to lateral meniscal repair.

Peripheral lateral meniscal tears are amenable to meniscal repair. Rasp abrasion and fibrin clot deposition along with vascular access channels are advances that, one hopes will increase healing rates of meniscal repairs. A basic principle that is not emphasized in the literature is how to perform the surgical approach to the lateral meniscus for safe placement of a meniscal repair retractor. This article reviews the anatomical planes of which the surgeon must be cognizant to facilitate retractor placement.     

Meniscal repair and transplantation: indications, techniques, rehabilitation, and clinical outcome

The purpose of this paper is to provide current knowledge regarding the indications, operative techniques, rehabilitation programs, and clinical outcomes of meniscus repair and transplantation procedures. Meniscus tears that occur in the periphery may be repaired using a variety of operative procedures with high success rates. Complex multiplanar tears that extend into the central one-third avascular zone can also be successfully repaired using a meticulous vertically divergent suture technique. The outcome of these repairs justifies preservation of meniscal tissue, especially in younger athletic individuals. Meniscal transplantation is a valid treatment option for patients who have undergone meniscectomy and have related tibiofemoral joint pain, or in whom articular cartilage deterioration in the meniscectomized compartment is present. Rehabilitation after these operations includes knee motion and quadriceps-strengthening exercises initiated the first day postoperatively. The initial goal is to prevent excessive weight bearing and joint compressive forces that could disrupt the healing meniscus repair or transplant. The protocol contains modifications according to the type of meniscal tear, if a concomitant procedure is done (such as a ligament reconstruction) or if noteworthy articular cartilage deterioration is present. Patients who have repairs of peripheral meniscus tears are generally progressed more rapidly than those who have repairs of tears extending in the central one-third region or those who undergo meniscal transplantation. The safety and effectiveness of the rehabilitation program has been demonstrated in several clinical studies. We recommend preservation of meniscal tissue, regardless of age, in active patients whenever possible.     

Meniscal rasping for repair of meniscal tear in the avascular zone.

We examined experimentally whether a longitudinal tear in the avascular zone of a rabbit meniscus can be healed by meniscal rasping. A full-thickness longitudinal tear 5-mm long was artificially created in the avascular zone of the anterior segment of both medial menisci. Meniscal rasping was then done on the femoral surface of the right meniscus from the parameniscal synovium to the inner segment including the tear. The left meniscus was left without further treatment as control. Two to 4 weeks after surgery, the hypertrophic synovium was observed invading from the parameniscal region to the injured portion. Eight to 16 weeks after surgery, the tear was almost completely healed. In contrast, neither hypertrophy of the synovium covering the tear nor healing was induced in the control meniscus. The mechanical test showed that there was a significant difference in the tensile strength and the stiffness of the injured portion between the rasped meniscus and the control meniscus. Meniscal rasping is easy to do, is effective, and causes few adverse effects with menisci. This procedure may be a treatment option for clinical cases of meniscal tear in the avascular zone for which we have no effective and clinically applicable methods at present, although further investigation is needed before clinical application.     

Non-operative treatment of meniscal tears

In a retrospective review of the results of 3,612 arthroscopic procedures that were performed for the treatment of an acute or a chronic meniscal lesion, with or without an associated ligamentous lesion, we identified eighty meniscal tears (in seventy-five patients) that had been assumed to be stable. Seventy were vertical longitudinal tears and ten were vertical radial tears. The seventy longitudinal tears included fifty-two lateral and eighteen medial meniscal lesions. All of the radial tears were in the lateral meniscus. Of the seventy-five patients, fifty-two had been followed for two to ten years. At the time of follow-up, only six of these fifty-two patients had needed additional intervention because of symptoms that were related to the meniscal tear. Four of them had the intervention after a sports-related traumatic extension of a stable tear, and two, because persistent symptoms were caused by the original meniscal lesion. A repeat arthroscopy was performed on thirty-two patients (twenty-six of whom had a longitudinal tear and six of whom had a radial tear), at an average of twenty-six months after the original arthroscopy. Seventeen of the twenty-six longitudinal tears had completely healed. Five of the six radial tears had no evidence of healing and one had extended. Neither ligamentous laxity nor a meniscal tear that was chronic at the time when it was discovered appeared to preclude healing of the stable longitudinal tears. No localized degenerative changes in the adjacent articular cartilage were found in association with any of the stable vertical longitudinal or radial meniscal lesions. Excluding the six patients who had had additional surgical treatment, none of the fifty-two patients who filled out a questionnaire reported that they had symptoms of a meniscal lesion, and none of the forty-two patients who were re-examined two years or more after the operation had signs of a meniscal lesion. Stable vertical longitudinal tears, which tend to occur in the peripheral vascular portions of the menisci, have great potential for healing. The tear should be left alone unless it is the only abnormality that is found and it is causing symptoms that warrant treatment. Stable radial tears, which tend to occur in the avascular inner one-third of the meniscus, have little potential for healing. Whether it is best to leave these lesions alone or to fashion an intact rim by contouring the meniscus was not established by this study.     

Meniscus Tears: Treatment in the Stable and Unstable Knee

Basic science research and follow-up studies after meniscectomy have provided convincing evidence of the importance of preservation of the meniscus in decreasing the risk of late degenerative changes. Whether in a stable or an unstable knee, if a meniscus tear cannot be repaired, a conservative partial meniscectomy should be undertaken to preserve as much meniscal tissue as possible. When feasible, repair should be carried out in young patients with an isolated meniscus tear, despite healing rates that are significantly lower than those obtained when meniscus repair is done with anterior cruciate ligament (ACL) reconstruction. The incidence of successful healing is inversely related to the rim width and tear length. In general, meniscus repair should be limited to patients under 50 years of age. Vertical longitudinal tears, including bucket-handle tears, are most amenable to repair. Some radial split tears can be repaired. In an ACL-deficient knee, meniscus repair is more prone to failure if not performed in conjunction with an ACL reconstruction, and is not recommended. Meniscal allograft surgery is investigational but may hold promise for selected patients.     

Meniscus repair and transplantation: a comprehensive update

Preservation of meniscal tissue is paramount for long-term joint function, especially in younger patients who are athletically active. Many studies have reported encouraging results following repair of meniscus tears for both simple longitudinal tears located in the periphery and complex multiplanar tears that extend into the central third avascular region. This operation is usually indicated in active patients who have tibiofemoral joint line pain and are less than 50 years of age. However, not all meniscus tears are repairable, especially if considerable damage has occurred. In select patients, meniscus transplantation may restore partial load-bearing meniscus function, decrease symptoms, and provide chondroprotective effects. The initial postoperative goal after both meniscus repair and transplantation is to prevent excessive weight bearing, as high compressive and shear forces can disrupt healing meniscus repair sites and transplants. Immediate knee motion and muscle strengthening are initiated the day after surgery. Variations are built into the rehabilitation protocol according to the type, location, and size of the meniscus repair, if concomitant procedures are performed, and if articular cartilage damage is present. Meniscus repairs located in the periphery heal rapidly, whereas complex multiplanar repairs tend to heal more slowly and require greater caution. The authors have reported the efficacy of the rehabilitation programs and the results of meniscus repair and transplantation in many studies.     

Arthroscopic repair of meniscus tears extending into the avascular zone with or without anterior cruciate ligament reconstruction in patients 40 years of age and older

Purpose: The purpose of this study was to prospectively determine the outcome of meniscal repairs for tears that extended into the central one-third zone of the meniscus, or had a rim width of 4 mm or greater, in a case series of patients 40 years of age and older. Type of Study: Prospective case series. Materials and Methods: Thirty meniscal repairs in 29 patients were evaluated by a comprehensive examination (28 repairs) a mean of 34 months postoperatively, by follow-up arthroscopy (6 repairs) a mean of 24 months postoperatively, or both. The mean age of the patients at the time of the meniscal repair was 45 years (range, 40 to 58 years). Twenty-one patients (72%) also had ruptures of the anterior cruciate ligament, which were reconstructed at the time of the meniscal repair with bone–patellar tendon–bone autografts (16 patients) or allografts (5 patients). The Cincinnati Knee Rating System was used to rate symptoms, functional limitations with sports and daily activities, patient perception of the knee condition, and sports and occupational rating levels. Results: At a mean of 33 months postoperatively, 26 meniscal repairs (87%) were asymptomatic for tibiofemoral joint symptoms and had not required subsequent surgery. Three repairs failed to heal, requiring partial meniscectomy, and 1 knee with tibiofemoral symptoms related to the repair was treated conservatively. There was no significant effect of the side of the meniscal repair, chronicity of injury, or condition of the articular cartilage on the presence of tibiofemoral symptoms or meniscal resection. Concomitant anterior cruciate ligament reconstruction appeared to increase the rate of asymptomatic meniscal repairs. The patient rating of overall knee condition was normal/very good in 76%, good in 12%, and fair/poor in 12%. Conclusions: In athletically active patients, we recommend the preservation of meniscal tissue wherever possible regardless of age, basing indications for the procedure on current and future activity levels.     

George Peters Award. Microscopic anatomy within the nipple: implications for nipple-sparing mastectomy

BACKGROUND: Precise anatomical relationships between ducts and vasculature within the nipple remain unknown. This study investigated nipple microvessels and their position relative to ducts. METHODS: Nipple and duct bundle cross-sectional areas were measured in 48 specimens. Vessels located within the central duct bundle or within a peripheral rim were counted in 7 non-irradiated and 5 irradiated nipples. RESULTS: Mean nipple diameter was 11.1 mm and duct bundle diameter 5.2 mm. A 2-mm and a 3-mm peripheral rim of nipple tissue would result in complete duct excision in 96% and 87% of sections, respectively. Twenty-nine percent of vessels are located in the duct bundle. A 2-mm rim contains 50%; a 3-mm rim contains 66%. Similar proportions were seen in irradiated nipples. CONCLUSIONS: This study describes a strategy to balance duct removal with vascular preservation. Ducts can be excised leaving a rim of nipple tissue that contains a large proportion of microvessels.     

Editorial Commentary: Meniscus Tears Seen at the Time of Anterior Cruciate Ligament Reconstruction Are Overtreated

Meniscus tears seen at the time of anterior cruciate ligament reconstruction are usually asymptomatic, and treatment varies greatly between surgeons, with meniscus repair being used for tears that could be left in situ. Recent outcome studies of most types of lateral meniscus tears show that leaving the tears in situ can give equal or superior results. Meniscus repair being performed for degenerative medial meniscus tears does not give better results than removing the tears. As an alternative to repair, trephination through the meniscus into the peripheral capsule can create many bloody channels to promote healing. Long-term follow-up of meniscus treatment with anterior cruciate ligament reconstruction can help us understand outcomes and prevent us from overtreating tears.     

Editorial Commentary: Moving the Needle: Traditional Inside-Out Meniscal Repair Has Advantages Over All-Inside Repair

Meniscus repairs for vertical, peripheral tears can be troublesome due to poor tissue quality and/or vascularity that can lead to re-rupture and subsequent removal. The gold standard, inside-out repair technique, has been challenged by all-inside devices for the benefit of improved efficiency and less morbidity but for the sake of expense and potential structural inferiority. Successful meniscus repair requires multiple components, only one of which is deciding the repair construct of choice. I feel the most important aspect will always be the indication based on tear configuration while respecting biology, because all fixation will eventually fail if the meniscus does not ultimately heal. While all-inside devices may have biomechanical properties that are similar to inside-out techniques, the burden of proof still lies on showing superiority of these devices in a clinical setting. Clinically, I still use inside-out repair techniques for large tears or for high-demand patients due to its structural integrity and small penetration of the meniscus.     

关节镜下修补半月板桶柄样撕裂的临床疗效分析

目的 探讨关节镜下修补半月板桶柄样撕裂的临床疗效.方法 关节镜下对61例63个桶柄样撕裂的半月板行修补手术,男38例,女23例;年龄16～47岁,平均27岁.内侧半月板后体部至前体部区域撕裂及外侧半月板胴肌腱前方区域撕裂采用标准的白内向外缝合技术;内侧半月板后角区域撕裂采用经两个后内侧入路的全关节内缝合技术;外侧半月板后角区域撕裂采用经前方关节镜入路的全关节内缝合技术.结果 61例63个半月板随访时间24～66个月,平均38个月.其中51例(53个半月板)行二次关节镜检.44个半月板(83%)完全愈合,5个半月板(9.4%)部分愈合,4个半月板(7.5%)不愈合.61例患者均进行临床评估,其中53例(87%)无临床症状,4例(6.5%)有部分临床症状,4例(6.5%)绞锁复发.总体评估:失效率为7.9%(5/63),成功率92.1%(包括完全愈合、部分愈合、无临床症状及部分临床症状者).结论 对于发生在红一红区或红一白区的半月板桶柄样撕裂,采用多种缝合技术进行牢靠的修补缝合,并且与前十字韧带重建同期进行,可以获得约92%的成功率.     

Meniscal repair: indications and techniques

Meniscal tears are exceedingly common. Because the meniscus serves many vital functions to the knee joint, the preservation of meniscal tissue through meniscal repair is ideal. However, not all meniscal tears are amenable to repair, and each case must be critically assessed for repair suitability. It has been well documented that meniscal healing is enhanced in the setting of concurrent anterior cruciate ligament (ACL) reconstruction. This may influence the indications for repair, as well as the repair technique. Meniscal repair techniques have evolved over time from initial open repairs to inside-out and outside-in suture repairs to newer all-inside repair devices. The current gold standard remains inside-out vertical mattress suture repairs. All-inside repairs are best reserved for special circumstances, such as in the setting of concurrent ACL reconstruction.