Discoid lateral meniscus in children: limited knee extension and meniscal instability in the posterior segment

BACKGROUND: Limited knee extension is a well-known sign in children with discoid meniscus, but its causative mechanism is controversial. The purpose of this study was to characterize discoid meniscus with this clinical manifestation with a focus on instability of the posterior segment and its morphologic features. METHODS: The authors retrospectively reviewed magnetic resonance imaging and intraoperative arthroscopic videos of 34 knees in 32 consecutive patients (age range, 4.5-15.0 years) who underwent arthroscopic treatment for symptomatic discoid lateral meniscus. Knees were classified into 2 groups, depending on the presence (n = 19) or absence (n = 15) of an extension block, which was defined as a limitation of knee extension by 10 degrees or more under general anesthesia. Meniscal instability in the posterior segment was determined based on arthroscopic findings, and its correlation with knee extension block was analyzed. Using magnetic resonance imaging, the thicknesses of anterior and posterior segments were measured to assess significance of the thickness differences by a presence of knee extension block and by the posterior segment instability. RESULTS: There were 13 knees with a stable posterior segment and 21 knees with an unstable posterior segment. Meniscal instability in the posterior segment was observed in the knees with a surface tear (n = 12), in a hypermobile posterior rim despite the absence of a surface tear (n = 5), and in knees with a freely movable posterior rim without posterior tibial attachment (n = 4). Knee extension block occurred exclusively in complete type menisci and was significantly correlated with meniscal instability in the posterior segment. Magnetic resonance imaging observations suggested that morphologic features characteristic of thick anterior and thin posterior segments were significantly associated with meniscal instability in the posterior segment. Clinically, knee extension block disappeared in all cases within 4 months of arthroscopic treatment. CONCLUSIONS: A redundant anterior segment associated with meniscal instability in the posterior segment is likely to cause limited knee extension in children with discoid lateral meniscus. This correlation mandates that discoid menisci be thoroughly evaluated during arthroscopic treatment to identify any instability that might require stabilization.     

Congenital discoid lateral meniscus in children. A follow-up study and evolution of management

Fifty-two children with 62 discoid lateral menisci were reviewed at an average follow-up of 5.5 years. Their average age at operation was 10.5 years and the mean delay in diagnosis was 24 months. Most of the children had vague and intermittent symptoms and the classical clunk was demonstrable in only 39% of the knees. An associated osteochondritis dissecans of the lateral femoral condyle was seen in seven knees. Forty-eight knees with symptomatic torn discoid menisci underwent open total lateral meniscectomy, six had arthroscopic partial meniscectomy and eight knees with intact discoid menisci, were left alone. Based on Ikeuchi's grading (Ikeuchi 1982), 37% of the knees had an excellent result, 47% had a good result and 16% had a fair result: none was poor. Arthroscopic partial meniscectomy is recommended only when the posterior attachment of the discoid meniscus is stable. A total meniscectomy is indicated for the Wrisberg-ligament type of discoid meniscus with posterior instability.     

Arthroscopic treatment of the discoid lateral meniscus: results of long-term follow-up

Twenty-two patients (25 knees) were evaluated at an average follow-up of 54 months for clinical results of arthroscopic treatment of the discoid lateral meniscus syndrome. Discoid lateral menisci were classified arthroscopically as incomplete (92%) or complete (8%); no Wrisberg-type lesions were noted. Three patients (14%) had bilateral lesions. Symptomatic torn discoid menisci (20 knees) and torn discoid menisci with other significant symptomatic lesions (3 knees) underwent arthroscopic partial lateral meniscectomy utilizing the saucerization technique. Asymptomatic intact discoid menisci (2 knees) were left unresected. Using the knee scale of Ikeuchi, 55% of the symptomatic torn lesions were rated as excellent or good, 30% were rated as fair, and 15% were rated as poor at follow-up. Two of the 3 asymptomatic torn lesions were rated as excellent or good, as were both of the intact discoid lesions. Factors associated with an unsatisfactory rating at follow-up included preexistent degenerative changes, age, and sex. Duration of symptoms, type of discoid tear, and length of follow-up were not necessarily related to outcome results. Seven knees (28%) required arthroscopic reevaluation at a postoperative average of 23 months, documenting apparent physiologic function of the saucerized rim in 4 patients and failure of saucerization in 3 patients (12%). Overall, 14 of the 22 patients in this study (64%) resumed a normal activity level postoperatively, including 61% of those with symptomatic torn discoid lateral menisci.     

膝盘状软骨的关节镜治疗

目的：探讨关节镜诊断治疗膝关节盘状软骨的作用。材料与方法：1995年9月－1999年12月关节镜治疗外侧盘状软骨38例。部分切除20例,次全切除14例,全切4例。结果：随访6个月－4年3个月,关节功能正常、症状消失30例。偶有疼痛3例,关节弹响1例,肌萎缩无改善2例,膝关节屈伸轻度受限2例。结论：盘状软骨镜下切除术保留软骨的宽度取决于盘状软骨的类型、撕裂范围和位置。保留的软骨应稳定、紧张;保留软骨形成的“半圆箍”应完整;术中活动膝关节无弹跳。     

Cautious surgery for discoid menisci

This retrospective study reviewed the outcomes of 43 knees in 38 patients with discoid menisci treated from 1977 to 1989. Patients underwent either no treatment, trimming, or subtotal or total resection. Approximately 40% of patients who underwent meniscectomy or partial meniscectomy had a fair or poor rating after an average follow-up of 6.5 years. Pathology demonstrating mucoid fibrinous degeneration within the discoid meniscus was found in many cases, showing abnormal meniscal tissue. Only one third of these knees had symptoms of locking, and only 20 (63%) of 32 had a positive arthrogram, demonstrating the diagnostic difficulties encountered with the discoid meniscus. Patients with a discoid meniscus who are symptomatic should undergo arthroscopy. A partial meniscectomy should be performed to achieve a smooth meniscus and a strong, stable peripheral rim.     

Arthroscopic meniscectomy for discoid lateral meniscus in children and adolescents: 10-year follow-up.

Seventeen adolescents underwent arthroscopic lateral meniscectomy for discoid lateral meniscus. The average age at surgery was 13.6 years (range: 5-18 years). The main preoperative symptom was pain in 16 knees and extension loss in 1 knee. At arthroscopy, 10 menisci were complete, 4 were incomplete, and 3 were Wrisberg type. Arthroscopic total meniscectomy was performed in the 3 Wrisberg types, 2 complete types, and 1 incomplete type. The remaining menisci underwent partial meniscectomy. The average follow-up was 10 years (range: 5-15 years). According to the Ikeuchi rating system, 12 knees were rated as excellent (no symptoms and full range of motion), 4 were rated as good (occasional pain), and 1 was rated as fair (patellofemoral pain in an obese patient). Radiographic evaluation showed development of minor osteophytes in the lateral compartment of 8 knees and <50% narrowing of the lateral joint space in 11 knees. No correlation was found between meniscal type, type of meniscectomy (partial or total), and clinical and radiographic results. Arthroscopic lateral meniscectomy for discoid lateral meniscus in adolescents was effective in relieving symptoms during a 10-year follow-up period. Longer follow-up is needed to ascertain the significance of the radiographic changes seen in this study.     

成形缝合术治疗外侧盘状半月板损伤的短期疗效

目的回顾分析关节镜下成形联合缝合修补术治疗不稳定外侧盘状半月板损伤的手术方法和短期疗效。方法采用关节镜下半月板成形缝合术治疗不稳定外侧盘状半月板损伤患者22例（24膝）,随访时采用Lysholm评分评价手术疗效。结果术后随访12～30个月,平均18．1个月。术前Lysholm评分（62．3±5．4）分;术后12个月（93．4±5．6）分（P〈0．05）,优良率为95．5％。结论只要手术指证掌握正确,采用关节镜下半月板成形联合缝合修补术治疗不稳定外侧盘状半月板手术效果良好。     

关节镜下盘状半月板的治疗

目的　探讨关节镜下盘状半月板的治疗方法与疗效。　方法　 37例 (37膝 )盘状半月板 ,33例行关节镜下成形术 ,4例肌腱部自关节囊缘较广泛撕裂因无法成形而行全切术。 1例自R区纵向撕裂在成形后行缝合修补术。　结果　按Ikeuchi氏膝关节评价等级 :优 19例 (5 1.4% ) ,好 13例(35 1% ) ,良 5例 (13 5 % )。　结论　关节镜下盘状半月板成形术可获得优良疗效 ,主张尽可能施行关节镜下成形术治疗盘状半月板。     

Bilateral Discoid Medial Menisci

Summary: This article adds 2 more cases of bilateral discoid medial menisci to the previously reported 9 cases. The radiographs of the first case revealed bilateral cupping of the medial tibial plateaus and a small lytic lesion of the left distal medial femoral metaphysis. Beside the posteriorly unstable incomplete type discoid medial meniscus, the left knee had several associated arthroscopic findings: depression of the medial tibial plateau with exposed subchondral bone, anomalous insertion of the anterior horn of the discoid meniscus to the anterior cruciate ligament, a pathological medial plica, and longitudinal deep fissures in the trochlea. The second case was a complete type with peripheral horizontal cleavage tears. Following arthroscopic surgery, magnetic resonance imaging (MRI) scans of the contralateral knees were obtained in both cases to search for bilaterality. MRI revealed discoid medial menisci in the unoperated knees as well. The short-term results of arthroscopic meniscectomy may not be as satisfactory as those reported for normal menisci.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 16, No 1 (January-February), 2000: pp 96–101     

Discoid meniscus

The discoid meniscus is an uncommon but not remote meniscal anomaly. Watanabe classified discoid menisci into three types: complete, incomplete, and Wrisberg-ligament type. These menisci vary in size, shape, presence of a posterior meniscal attachment, and mode of presentation.The complete and incomplete types are usually incidental arthroscopic findings unless they present with symptoms of an associated meniscal tear. The Wrisberg variant presents with the snapping knee syndrome, with visible, and often audible dunking with flexion and extension of the knee. The complete and incomplete types should be left alone unless there is an associated meniscal tear, in which case a saucerization procedure should be performed. The Wrisberg variant should have attachment of its hypermobile posterior horn.     

203例盘状半月板的关节镜治疗和探讨

目的 :探讨盘状半月板损伤的机制和特点 ,研究残留半月板组织的处理原则。方法 :对 2 0 3例行关节镜诊治的盘状半月板病例的临床资料进行分析 ,探讨盘状半月板患者的年龄分布特点和 14岁以下半月板损伤患者中盘状半月板病例的比例。对上述资料进行统计学分析。结果 :盘状半月板损伤患者的年龄分布 ,在 2 0岁以下组患者数量最多 ,较其它组有显著差异 (P <0 .0 5 )。14岁以下半月板损伤的患者中外侧盘状半月板组所占比例与普通半月板组比较有显著差异 (P <0 .0 5 )。结论 :盘状半月板的症状、体征和MRI有其相对的特殊性 ,其年龄分布显示青少年患者较多。盘状半月板损伤的机制与其解剖特征和组织学构成有关 ,镜下治疗的原则是保留一个外形和厚度接近正常 ,边缘稳定、光滑的半月板组织。     

Arthroscopic meniscectomy for discoid lateral meniscus in children and adolescents: 4.5 year follow-up

We retrospectively reviewed the 4.5 year (range, 21-88 months) follow-up results of arthroscopic partial meniscectomies performed in 11 knees between 1994 and 2000 to treat a symptomatic discoid lateral meniscus. The average age at surgery was 11.5 years (range, 5-17 years). All except one of the discoid menisci were of a complete type, and all except three were torn menisci. At the latest follow-up examination, the result was excellent for nine knees, and good for two; no degenerative changes were evident on the roentgenograms. Arthroscopic partial meniscectomy should be the treatment of choice for the complete type symptomatic lateral discoid meniscus, even if it is intact. Preoperative lack of the knee extension requires a gentle rehabilitation program postoperatively.     

Management of discoid lateral meniscus tears: Observations in 34 knees

Purpose: The goal of this study was to evaluate arthroscopic partial resection of discoid lateral meniscus tears with an emphasis on radiographic evidence of degenerative changes after this procedure. Type of Study: Retrospective clinical study. Methods: Of 41 patients with an arthroscopic diagnosis of discoid meniscus over an 8-year period, 34 symptomatic lateral discoid meniscus tears in 33 patients were analyzed at an average follow-up of 5.6 years. The average age at operation was 19.8 years and most patients had vague and intermittent symptoms that caused delay in clinical diagnosis. Results: Eight patients were lost to follow-up and were excluded from the study. Magnetic resonance imaging, performed in 12 cases, and arthroscopy in all of these patients provided the precise diagnosis. All of the knees with symptomatic torn discoid menisci underwent arthroscopic partial meniscectomy. Only 1 Watanabe Wrisberg ligament type of discoid meniscus with posterior instability was totally meniscected. Based on Ikeuchi's grading, 39% of the knees had an excellent result, 46% had a good result, and 15% had a fair result; none of the results was poor. Conclusions: At an average 5-year follow-up, partial meniscectomy in patients with a Watanabe complete or incomplete discoid meniscus showed 85% good or excellent clinical results. However, a significant percentage of patients show femoral condyle flattening on radiography.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 19, No 4 (April), 2003: pp 346–352     

Problems with repeated arthroscopic surgery in the discoid meniscus

To identify the main causes of repeated arthroscopic surgery of the knee joint and to find out the points of therapeutic approaches, we evaluated 139 patients who underwent arthroscopic meniscectomy in our department and in affiliated hospitals between 1983 and 1987. Two or more arthroscopic surgeries were needed in 9 knees of 8 patients (6.5%). In 5 knees with no known injuries, the primary reason for repeated surgery was horizontal tears of remnant meniscus after partial resection of lateral discoid meniscus. The most appropriate initial treatment for lateral discoid menisci in cases without tear should be observation of the clinical course with minimal treatment using diagnostic arthroscopy.     

Usefulness of knee arthroscopy for diagnosis of knee pain in pediatric patients: comparison with preoperative clinical diagnosis

Purpose

To investigate the knee arthroscopic findings of pediatric patients with knee pain.

Subjects

Ninety-five knees of 94 patients (46 males and 48 females) aged 15 years or younger who underwent knee arthroscopy during a 4-year period from January 2007 were studied. The mean age at surgery was 13.5 (7–15) years. The mean interval from symptom onset to arthroscopic examination was 6.8 months (5 days to 2 years 10 months).

Results

The most common cause of knee pain was sports-related activities (64 knees). Other causes included falling from a moving bicycle (5 knees), while knee pain appeared with no defined reason in 14 knees. The most frequent final diagnosis based on knee arthroscopic findings was anterior cruciate ligament (ACL) injury (35 knees), followed by discoid lateral meniscus (16 knees), lateral meniscal tear (11 knees), and medial plica syndrome (9 knees), while no arthroscopic abnormality was observed in 8 of 95 knees. Among the 95 knees, the diagnosis based on preoperative physical tests and imaging findings was different from the arthroscopic diagnosis in 16 knees, 8 of which were diagnosed preoperatively as medial meniscal tear.

Conclusion

ACL injury and discoid lateral meniscus were the predominant conditions in pediatric patients who underwent knee arthroscopic surgery for knee pain. Knee arthroscopy is useful to provide a definitive diagnosis for knee pain in pediatric patients. Preoperative evaluations had a diagnostic accuracy of only 83.2 % and failed to diagnose conditions such as medial plica syndrome and chondral injury. Therefore, diagnosis before knee arthroscopy has to be interpreted with caution.     

Repair of peripheral meniscal tears: open versus arthroscopic technique

Tears in the peripheral vascular zone of 71 menisci in 68 knees were repaired by us from 1978 to 1986. The meniscus repair was done by open arthrotomy in 26 cases and by arthroscopic techniques in 45 cases. We have assessed the relative efficacies of open and arthroscopic repair techniques. The results were compared in knees with and without anterior cruciate laxity. The indications for meniscal repair included unstable peripheral detachments and longitudinal tears of the outer third of the meniscus. Open repair was performed by a posteromedial arthrotomy incision. Arthroscopic repair was done using the double-lumen guide system with a limited posterior incision for retrieval of needles. We have found that the arthroscopic technique is easier to perform than the open repair because some tears are too far inside the rim to lend themselves to open suture. The average follow-up is 4 years, 2 months, with a range of 2-10 years. There have been no neurologic or vascular injuries from either technique. Twenty-five patients have had a repeat arthroscopy. The overall failure rate was 9.8%. The difference between the failure rate of 11% in the open-repair group and 8.8% in the arthroscopic repair group was not statistically significant. The failure rate in anterior cruciate-stable knees was 8% versus a 13% failure in cruciate-deficient knees. We conclude that both open and arthroscopic meniscus repair techniques are safe and effective with few complications in both stable and unstable knees. Anterior cruciate ligament stability is ideal, but it is not mandatory for a successful result.     

半月板成形和缝合治疗累及腘肌腱裂孔的盘状软骨损伤

目的 总结关节镜下半月板成形和胴肌腱裂孔前、后缝合治疗累及腘肌腱裂孔的外侧盘状软骨损伤临床疗效.方法 2008年1月-2009年5月,收治21例累及腘肌腱裂孔的外侧盘状软骨损伤患者.男9例,女12例;年龄12～45岁,平均22.5岁.左膝12例,右膝9例.7例既往有外伤史,14例无明确外伤史.病程3个月～2年,平均6....     

误诊为半月板损伤的弹响膝122例分析

目的探讨误诊为半月板损伤患者弹响膝的发生机制、临床表现、诊断和关节镜治疗。方法回顾性分析122例术前误诊为半月板损伤的弹响膝患者资料,所有患者均接受膝关节镜手术。分析不同病因导致膝关节弹响的部位、响度、发生频率、镜下表现,最终评价关节镜手术疗效。结果许多疾病均可出现膝关节弹响,最常见原因为半月板损伤,其次是关节内游离体、软骨病变、滑膜病变、髌股关节紊乱、韧带及肌腱损伤等。其弹响各有特点,关节镜诊治后91．8％弹响症状完全消失,少数患者残余部分症状？结论膝关节弹响来源多样,半月板源性的弹响最为常见。掌握弹响特点有助于术前正确诊断,提高手术疗效,避免过度医疗。关节镜手术是诊治弹响膝的金标准。     

Relationship between osteochondritis dissecans of the lateral femoral condyle and lateral menisci types

The purpose of this study was to examine the relationship between osteochondritis dissecans (OCD) of the lateral femoral condyle and lateral menisci. From 1993 to 2002, 38 knees (28 patients) were diagnosed with OCD of the lateral femoral condyle. OCD locations were graded by the Cahill and Berg classification. The types of lateral menisci were classified by Watanabe's classification. The relationship between OCD of the lateral femoral condyle and lateral menisci was examined. On the anterior-posterior view, 25 OCDs were located in zone 4 and 13 in zone 5. The types of lateral menisci were complete discoid in 19 knees, incomplete discoid in 15, and normal in 4. Ten of the 19 complete discoid menisci were damaged. Complete discoid menisci without tears were found in OCDs located in zone 4; incomplete discoid menisci were found in OCDs located in zone 5. The authors found a relationship between the type of OCD and the state of the lateral meniscus.     

Meniscus repair: results of an arthroscopic technique

A prospective study of arthroscopically repaired peripheral meniscal tears in 24 patients (19 men and five women) was initiated in 1983. Two patients were lost to follow-up. Seventeen medial and five lateral tears were followed an average of 29 months (15-42 months) with 17 having clinically apparent healing (77%). Sixteen had ACL tears, 10 of which were stabilized. Thirteen of 16 stable knees healed their menisci (81%), whereas only 4 of 6 unstable knees had healed menisci (67%). Fifteen were acute tears repaired within 2 weeks of injury, and 7 were chronic tears. Four acutely repaired menisci failed. One lateral meniscus tore in the previously sutured site 12 months later, whereas 1 medial meniscus tore 24 months after repair in a new area associated with significant trauma. Repair of a longitudinal peripheral meniscal tear permits salvage of this structure in a high percentage of cases. No serious complications such as peroneal nerve or popliteal vascular damage occurred. Transient saphenous neuropraxia (22%) and posterior portal adhesions (9%) were temporary problems. The procedure is recommended only for the advanced arthroscopist, who is advised first to establish the anatomical relationships clearly by cadaver dissections.