Instrumented evaluation of knee laxity: a comparison of five arthrometers.

We performed a prospective study on 50 subjects with normal knees and 50 patients with chronic unilateral disruption of the anterior cruciate ligament. In a randomized testing sequence, both groups were examined with five arthrometers: the MEDmetric KT-1000, the Stryker Knee Laxity Tester, the Acufex Knee Signature System, the Dyonics Dynamic Cruciate Tester, and the Genucom Knee Analysis System. Each examination was performed according to protocol with the knee at 30 degrees of flexion. The total anterior laxity measurements of the normal subjects using the Dyonics Dynamic Cruciate Tester and Acufex Knee Signature System were approximately half of the KT-1000, Stryker, and Genucom values. A comparison of the side-to-side measurements revealed no statistically significant difference in the values of the five arthrometers. However, the Genucom showed an unacceptably high number of normal subjects with laxity values that suggested an anterior cruciate ligament tear. Total anterior laxity measurements of the anterior cruciate ligament deficient knees were almost twice those of normal knees with each device except the Genucom. Comparison of the mean side-to-side difference in the patients with ACL deficiency demonstrated statistically significant differences in the values recorded with the five arthrometers. The side-to-side difference was greatest with the KT-1000 and least for the KSS. In the 89 N Lachman test, the KT-1000 and Stryker demonstrated the highest diagnostic accuracy. The maximum manual test improved the accuracy of each device. This study establishes the total anterior laxity measurements cannot be generalized from one device to another in either group of subjects.(ABSTRACT TRUNCATED AT 250 WORDS)     

Instrumented measurement of anterior knee laxity in patients with acute anterior cruciate ligament disruption

Instrumented anterior/posterior laxity measurements were performed on 138 patients evaluated within 2 weeks of injury with their first traumatic knee hemarthrosis. All patients were tested with the MEDmetric Arthrometer model KT-1000 in a knee injury clinic. Seventy-five of the patients had knee arthroscopy. Thirty-three had arthrometer laxity tests under anesthesia. Eighty-seven percent of patients arthroscoped had anterior cruciate ligament (ACL) tears and 41% had meniscus tears. One hundred twenty normal subjects were tested to establish normal anterior laxity values. Three tests were used to evaluate anterior laxity: anterior displacement between a 15 and 20 pound force (compliance index), anterior displacement with a 20 pound force, and anterior displacement with a high manually applied force. Displacement measurements in normal subjects revealed a wide range of normal laxity with a small right knee-left knee difference. For example, the 20 pound anterior displacement range was 3 to 13.5 mm with a right knee-left knee difference (mean +/- SD, 0.8 +/- 0.7 mm). Eighty-eight percent of the normals had a right-left difference of less than 2 mm. In the 53 patients arthroscoped who had complete ACL tears, the anterior laxity measurements performed in the clinic were suggestive or diagnostic of pathologic anterior laxity in 50 patients.     

Assessing the limits of knee motion

Ten patients were examined clinically by 11 experienced knee surgeons and with three measurement devices (Genucom, Knee Signature System, and KT-1000). Nine of the 10 patients examined had sustained documented intraarticular ligament disruptions including eight ACL disruptions and five posterior cruciate ligament disruptions. The eight patients with ACL injuries had undergone reconstructive surgery. The clinical examination test sequence was performed as described by the International Knee Documentation Committee. Testing results were reported as estimated degrees of angulation or millimeters of displacement. Testing results were divided into two groups based on the index minus nonindex knee difference. Eighteen displacement tests were performed on each knee by each examiner. The index minus nonindex knee difference was greater than 3 mm in 16% of the tests. Only 1 of the 198 displacement tests performed on the subject who did not have a ligament disruption was recorded as an index minus nonindex difference greater than 3 mm. There was appreciable difference between measurements recorded by different examiners, particularly anterior/posterior measurements in patients who had sustained combined anterior and posterior cruciate ligament injuries. There is a need to rigorously evaluate limits of motion tests that are used to develop treatment plans and report the results of ligament surgery.     

Radial tears in the roots of the posterior horns of both the medial and lateral menisci combined with anterior cruciate ligament tear: a case report

We report a rare case of radial tears in the roots of the posterior horns of both the medial and lateral menisci associated with a chronic anterior cruciate ligament tear. Treatment included an arthroscopic pullout suture combined with anterior cruciate ligament reconstruction. At the 3-year postoperative follow-up, a second-look arthroscopic examination showed the posterior horns of both menisci to be well healed on the tibia. Manual knee laxity tests were negative and no side-to-side difference was detected by a KT-1000 arthrometer. The patient was able to perform outdoor activities without residual symptoms.     

Knee-laxity measurements examined by a left-hand- and a right-hand-dominant physiotherapist,in patients with anterior cruciate ligament injuries and healthy controls

The purpose of the study was to analyse and compare KT-1000 knee laxity as examined by a left-hand- and a right-hand-dominant physiotherapist in a group of patients with an anterior cruciate ligament (ACL) injury and a group of patients, 2 years after ACL reconstruction. The other aim was to measure and analyse knee laxity in a group of persons without any known knee problems. A cross-sectional examination of two groups of patients pre-operatively and post-operatively after ACL reconstruction and examination of healthy controls on two different occasions was performed. Fifty-three patients who were scheduled for ACL reconstruction and 39 patients who attended a 2-year follow-up examination were included in the study. In the ACL-deficient group, 32 patients had a right-sided ACL injury and 21 patients a left-sided ACL injury. The corresponding figures in the post-operative group were 21 patients with a right-sided ACL injury and 18 patients with a left-sided ACL injury. Twenty-eight healthy persons without any known knee problems served as controls. One left-hand- and one right-hand-dominant experienced physiotherapist performed all the examinations. To be able to evaluate the intra and inter-reliability of the examiners the controls were examined at two occasions. The left-hand-dominant physiotherapist measured significantly higher absolute laxity values in the left knee, both injured and non-injured ones, compared with the right-hand-dominant physiotherapist. This was found irrespectively of whether the patients belonged to the ACL deficient or the post-operative group. In the healthy control group, the right-hand-dominant physiotherapist measured significantly higher knee-laxity values in the right knee compared with the left-hand-dominant physiotherapist. Correspondingly, the left-hand-dominant physiotherapist measured significantly higher knee laxity values in the left knee. We conclude that KT-1000 arthrometer laxity measurements can be affected by the hand dominance of the examiner. This might affect the reliability of KT-1000 arthrometer measurements. Level of evidence is II.     

KT-1000 records smaller side-to-side differences than radiostereometric analysis before and after an ACL reconstruction

The KT-1000 and similar non-invasive arthrometers are used as a complement to clinical examination in the diagnosis of anterior cruciate ligament (ACL) rupture and during the follow-up after surgery. We compared the two methods, KT-1000 and Radiostereometric analysis (RSA), when used to measure anterior-posterior knee laxity (A-P laxity) in patients with ACL rupture, before and after the reconstruction of this ligament, in a prospective, comparative study. Twenty-two consecutive patients (14 men, 8 women) with a median age of 24 years (range 16–41) were studied. All the patients had a unilateral ACL rupture and an intact contralateral knee. The patients were operated on by one experienced surgeon using the bone-patellar tendon-bone (BTB) autograft. Preoperatively and 2 years after the reconstruction, all the patients were evaluated using KT-1000 and RSA measurements of A-P laxity. The side-to-side differences between the injured and the intact knees, that is, total A-P laxity for both knees, are presented. Preoperatively, the median side-to-side differences using the two methods (KT-1000/RSA) were 4.0 (0–10)/7.4 mm (2.2–17.4) (P<0.0001). The total A-P laxity on the injured side was 11.0 (6.0–18.0)/10.9 mm (6.2–19.6) (n.s), while it was 8.0 (6.0–10.0)/3.1 mm (0.2–8.6) on the intact side (P<0.0001). A side-to-side difference of more than 3.0 mm was defined as the cut-off value for indicating ACL rupture. Using the KT-1000, 11 of 22 (50%) patients had a cut-off value above 3.0 mm, while the corresponding figure for RSA was 21/22 (95%) patients. At the 2-year follow-up, the median side-to-side differences using the two methods (KT-1000/RSA) were 0.5 (−1.5 to 4.0)/2.8 mm (−1.8 to 10.7) (P<0.0001). The total A-P laxity on the operated side was 9.5 (7.5–14.0)/6.5 mm (2.4–14.1) (P<0.0001). We conclude that the KT-1000 recorded significantly smaller side-to-side differences than did the RSA, both before and after the reconstruction of the ACL using a BTB autograft. Before it was mainly an effect of larger A-P laxity recordings with KT-1000 on the intact side, and after the reconstruction, the KT-1000 still recorded larger A-P laxity on the intact side and also larger A-P laxity on the reconstructed side than RSA.     

Evaluation of the reproducibility of the KT-1000 arthrometer

The aim of the study was to examine whether the KT-1000 arthrometer was reliable when it came to distinguishing between a group of patients with a chronic anterior cruciate ligament (ACL) rupture and a group of patients without an ACL rupture, and to examine the reproducibility of the examination between two experienced examiners. The aim was also to examine whether the KT-1000 measurements were dependent on whether the patients were awake or under anaesthesia. The study comprised 40 patients: Group A consisted of 20 patients who had a chronic unilateral ACL rupture and Group B consisted of 20 patients who were scheduled for arthroscopy due to knee problems other than an ACL rupture. The KT-1000 examination was performed before surgery by two experienced physiotherapists (PT I and PT II). PT II subsequently performed a retest of the patients under anaesthesia. The mean anterior side-to-side laxity difference between PT I and PT II was 0.2 mm in Group A and 1.8 mm in Group B (n.s., P=0.03). The anterior side-to-side measurements of knee laxity revealed significant differences between Group A and Group B, independent of who the measurements were made by when the patients were awake (PT I P=0.011, PT II P=0.001). However, no significant difference (P=0.063) was found when the patients were under anaesthesia. The interclass correlation coefficient (ICC) between PT I and PT II in Group A was 0.55 (P=0.005) for the anterior side-to-side laxity, while it was 0.60 (P=0.002) in Group B. There were no significant differences within Group A or Group B between the measurements made when people were awake compared with those under anaesthesia. The conclusions of the study were that the KT-1000 arthrometer was able to distinguish a group of patients with an ACL rupture from a group without one. The reproducibility of the KT-1000 measurements of anterior knee laxity between two experienced examiners was considered as fair. Furthermore, the measurements were not dependent on whether the patients were awake or under anaesthesia.     

The mid- to long-term results of the anterior cruciate ligament reconstruction with hamstring tendons using Transfix technique

In this study, mid to long-term results of anterior cruciate ligament reconstruction with hamstring tendons and Transfix technique were evaluated. Anterior cruciate ligament (ACL) reconstruction with four-strand hamstring tendon was performed with Transfix technique on 271 (198 males, 73 females; mean age 25.7; 17–52) patients with anterior cruciate ligament ruptures. The patients were followed up with clinical examination, Lysholm and Tegner activity scales, IKDC scoring system, KT-1000 test and radiological examination. The mean follow-up period was 82 (48–100) months; 204 (75%) patients had no subjective complaints. According to the KT-1000 test, only 14 (5%) patients had more than 5 mm laxity postoperatively, whereas, 161 (59%) patients had more than 5 mm laxity preoperatively. In addition to this, only 19 (7%) patients had Lysholm scores less than 80 postoperatively, whereas 154 (57%) patients scored less than 80 preoperatively. When compared with Tegner activity scale, 189 (70%) patients scored <6 preoperatively and only 24 (8%) postoperatively; 78 (29%) patients scored D preoperatively and only 5 (2%) patients scored D postoperatively on the basis of the IKDC scoring system. Our functional results were found to be satisfactory in more than 90% of patients. Commonly seen problems in ACL reconstruction such as inaccurate graft placement and tunnel widening were found to be consistent with the values in relevant literature. However, we demonstrated that the functional results and the stability of the knee were not related with tunnel widening. This study concludes that the reconstruction of ACL with hamstring tendons and the Transfix technique is reasonably successful, safe and causes low morbidity. Furthermore, we believe that proper graft preparation, accurate tunnel placement, notch-plasty, fixation and rehabilitation program are all as important as the choice of graft and fixation material.     

关节镜下异体骨-髌腱-骨纤维束重建治疗前交叉韧带部分损伤

目的 探讨异体骨-髌腱-骨纤维束（B-PT-B）重建前交叉韧带（ACL）全部纤维束和部分纤维束的早期疗效。方法在187例采用B-PT-B术式重建ACL的患者中，获得随访的ACL部分束损者共25例，其中采用全部纤维束重建的患者6例，部分纤维束重建19例。术后行X线和KT-1000检查，并按照IKDC、Lysholm、Irgang、Larson评分进行疗效评价。结果 所有患者随访时移植物位置良好，KT-1000检查双侧膝关节前向松弛度差值〈3mm。部分束重建组与全部束重建组各评分系统和分项评分系统无显著性差异。结论 异体B-PT-B重建治疗ACL部分损伤可以取得良好的临床疗效，与ACL全部束重建术相比综合评定无明显差异。     

Deep lateral femoral sulcus: study of 124 patients with anterior cruciate ligament tear

Abnormal deepening of the lateral femoral sulcus has been proposed as a potential indirect sign allowing the diagnosis of an anterior cruciate ligament (ACL) tear on conventional lateral knee radiographs. We studied a large group of patients with proven ACL tears during the acute injury and at 5-year follow-up to determine (a) the normal range of the depth of this sulcus and (b) the sensitivity, specificity, and positive predictive value of a deepened lateral sulcus. One hundred fifty patients with suspected ACL tears after sustaining unilateral injuries to their knees were referred to a specialty clinic for further evaluation. The injury was based on the presence of hemarthrosis, pathologic joint motion, and/or instability of the tibiofemoral joint. From this group, 124 patients were diagnosed with complete ACL tears (112 cases confirmed by arthroscopy, 12 cases diagnosed by the presence of pathologic motion with a KT-1000 arthrometer). Conventional radiographs of the injured knee were obtained in all 150 patients at the time of the acute injury. Five years later, radiographs of both the injured knee and the uninjured contralateral knee were evaluated. The lateral femoral condylopatellar sulcus, or notch, was measured on the acute injury and 5-year follow-up radiographs, and this measurement was compared to that on radiographs of the uninjured contralateral knee. The depth of the lateral sulcus consistently was noted to be similar in both knees in a given patient. Two groups of patients were identified: one group consisted of 124 patients with torn ACLs with a mean notch depth on the injured side of 0.57 mm [range, 0.0–3.3 mm; standard deviation (SD), 0.57 mm] and on the uninjured contralateral side of 0.43 mm (range, 0.0–2.0 mm; SD, 0.42 mm); and a second group consisted of those 26 injured patients with intact ACLs with a mean notch depth on the injured side of 0.31 mm (range, 0.0–1.0 mm; SD, 0.35 mm) and on the uninjured contralateral side of 0.27 mm (range, 0.0–0.8 mm; SD, 0.26 mm). Four of the 124 patients with a proven ACL tear had lateral notch measurements greater than 2.0 mm in depth. No patient with an intact ACL demonstrated a lateral sulcus that exceeded 2.0 mm in depth. A depth greater than 2.0 mm had a specificity of 100%, sensitivity of 3.2%, accuracy of 60%, and a positive predictive value of 100% for complete ACL tear. This work was supported in part by Veterans Affairs Grant SA 206.     

Who chooses anterior cruciate ligament reconstruction and why? A 2‐year prospective study

The purpose of this study was to investigate possible differences in age, gender, Tegner activity level prior to injury, knee joint laxity and the variables evaluated with knee osteoarthritis outcome score (KOOS) between patients who chose non-operative treatment (NT), early reconstruction (ER) and late reconstruction (LR). A second aim was to study whether patients who choose ER choose surgical treatment for the same reasons as patients who choose LR. Seventy-two patients with an acute (< 1 month) anterior cruciate ligament (ACL) tear, who had not yet decided to have surgery, were included in this study. They filled out the Tegner activity score, assessing preinjury activity level, KOOS and underwent KT-1000 arthrometer examination. The 36 subjects who later chose reconstruction were questioned about reasons for their decision. A high preinjury activity level was associated with the choice of ACL reconstruction, but the choice of treatment was not associated with age, gender or the outcome variables measured with KOOS or KT-1000. Fifteen out of the 20 (75%) subjects who chose ER based their decision on assumptions of future problems and not on experience of knee function. Fourteen out of 16 (88%) subjects, who chose reconstructive surgery later, based their decision on experience of knee function.     

Long-term failure of thermal shrinkage for laxity of the anterior cruciate ligament

BACKGROUND: Appropriate treatment for anterior cruciate ligament laxity, owing to partial tears of the native ligament or lax reconstruction, is unclear. Studies suggest that a significant percentage of these untreated tears may progress to complete tears or the patient may develop additional injuries to the meniscus or articular cartilage. Shrinkage of the ligament or graft using thermal energy has been proposed as a solution for this problem. PURPOSE: To evaluate the long-term results using thermal energy to shrink laxity of the anterior cruciate ligament. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Nineteen patients with partial tears of the anterior cruciate ligament (n = 14) or stretched anterior cruciate ligament grafts (n = 5) underwent thermal shrinkage treatment. Fourteen were available for follow-up at 1 and 5 years. At 1 year, there were 12 partial tears and 2 grafts available for evaluation. At 5 years, there were 10 partial tears and 4 grafts. Preoperative, postoperative, and intraoperative stability testing was performed using the KT-1000 arthrometer. Clinical results were evaluated using the Cincinnati and Lysholm scoring systems. RESULTS: Intraoperative shrinkage averaged 2.12 mm (17%, P < .0001). At 1 year, 12 of the 14 patients remained stable (86%) with a negative Lachman test result and mean KT-1000 arthrometer maximum side-to-side score of 1.29 mm (P < .001). The 2 failed shrinkages were partial tears of the native anterior cruciate ligament. For these 12 patients, Cincinnati scores improved from 53 to 89 (P < .0001), and Lysholm scores improved from 55 to 89 (P < .0003). At 5-year follow-up, 11 of 13 patients had gone on to complete failure (85%, P < .002; 8/9 partial tears and 3/4 grafts). CONCLUSION: Thermal shrinkage provides short-term benefit in the treatment of anterior cruciate ligament laxity but leads to catastrophic failure in the majority of patients at long-term follow-up. We can no longer recommend this procedure for the treatment of anterior cruciate ligament laxity.     

关节镜下应用LARS人工韧带同时重建前、后交叉韧带

目的 探讨关节镜下应用LARS人工韧带重建前交叉韧带(ACL)、后交叉韧带(PCL)同时损伤的方法及疗效. 方法 关节镜下同时重建13例ACL、PCL损伤的患者,重建材料采用LARS人工韧带.术后随访12～36个月,采用国际膝关节文件编制委员会(IKDC)韧带标准评价表和Lysholm膝关节功能评分表评估患膝功能,通过KT-1000检查膝关节前后松弛度.结果 术后无膝关节感染发生;均无伸膝受限,屈膝活动度105°～125°,平均117°.术后随访时IKDC评分:A类10例(77%),B类3例(23%).屈膝25°位KT-1000检查:双侧膝关节前向松弛度差异＜2 mm 12例,3～5 mm 1例;屈膝70°位检查:＜2 mm 12例,2～4 mm 1例.术前Lysholm膝关节功能评分为(63.8 ±2.9)分(49～69分),终末随访时为(91.1±2.7)分(88～95分),差异有统计学意义(P＜0.01). 结论 关节镜下同时重建膝关节ACL、PCL是目前治疗ACL、PCL同时损伤的一种微创、安全、有效的手术方法,近期疗效佳.     

Posterior horn lateral meniscal tears simulating meniscofemoral ligament attachment in the setting of ACL tear: MRI findings

PURPOSE: We have noted apparent far lateral meniscal attachment of the meniscofemoral ligament (MFL) with an anterior cruciate ligament (ACL) tear. This study evaluates MFL attachment and association with posterior horn lateral meniscus (PHLM) tear. MATERIALS AND METHODS: Nine months of knee arthroscopy reports were reviewed to classify the PHLM and ACL as torn or normal. After excluding those with prior knee surgery, MR images were reviewed by two radiologists to determine the number of images lateral to PCL, which showed the ligaments of Humphrey and Wrisberg visible as structures separate from the PHLM. Any patient with abnormal PHLM surface signal not continuous with the MFL was excluded. MRI findings were compared with arthroscopy using Student's t test and Fisher's exact test. RESULTS: Of the 54 participants, 5 had PHLM tears and 49 were normal. Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. The ligament of Humphrey inserted on average 0.9 consecutive images lateral to the PCL without an PHLM tear and 4.7 with an PHLM tear; the ligament of Wrisberg inserted on average 3.0 consecutive images without an PHLM tear and 4.5 with an PHLM tear (slice thickness/gap = 3 mm/0.5 mm). There was a significant association between PHLM tear and number of images (p = 0.0028), and between ACL tear and this type of PHLM tear (p = 0.0064). CONCLUSION: Apparent far lateral meniscal extension of a meniscofemoral ligament (greater than or equal to four images lateral to the PCL) should be considered as a possible PHLM tear, especially in the setting of an ACL tear.     

Acute rotational trauma to the knee: poor agreement between clinical assessment and magnetic resonance imaging findings

OBJECTIVES: To determine the incidence of anterior cruciate ligament (ACL) injuries in the general population; the pathology associated with a knee sprain verified by magnetic resonance imaging (MRI); and the agreement between clinical findings and MRI. MATERIAL AND METHODS: Inclusion criterion was an acute rotational trauma to the knee associated with effusion. One hundred and fifty-nine consecutive patients, mean age 27 years and 36% women, were included after clinical assessment at the orthopedic emergency unit. Patients were referred to an MRI examination (1.0 or 1.5 T) performed within a median of 8 days of the initial visit. RESULTS: The annual incidence of MRI verified ACL injuries was 0.81/1000 inhabitants aged 10-64 years. Fifty-six percent (n=89) of those included had sustained an ACL injury of whom 38% had an associated medial meniscus tear. There was a poor agreement between initial clinical antero-posterior laxity and MRI verified presence of an ACL tear (kappa 0.281). Every second patellar dislocation was diagnosed as a ligament injury. CONCLUSION: Our findings indicate that the incidence of ACL injuries is higher than previously described. We also show that the first clinical examination after an acute knee trauma has a low diagnostic value. Further assessment with MRI improves the chances of a correct diagnosis of intraarticular pathology and is recommended in the early phase after a rotational knee trauma.     

关节镜下4股半腱肌腱单束重建前交叉韧带部分损伤

目的 介绍关节镜下单束蕈建增强治疗前交叉韧带(anterior cruciate ligament,ACL)后外侧束部分损伤方法 ,探讨其临床效果. 方法 对26例单纯ACL后外侧柬部分损伤患者,在关节镜下采用自体半腱肌腱进行单束解剖重建.按照国际膝关节评分委员会(internationalknee documentation committee,IKDC)和Lysholm膝关节功能评分表对患膝功能进行评估,通过KT-1000检查比较膝关节的前向松弛度. 结果 术后无活动受限,屈膝活动度130°～150°,平均142°.术后随访12～18个月,最后随访时IKDC评分为A级25例(96%),B级1例(4%);IKDC评分从术前的(71.4±3.7)分提高到随访结束时的(95.8±3.4)分(t=9.836,P<0.01).屈膝25°位KT-1000检查,双侧膝关节胫骨结节前移差异从术前的(5.1±1.2)mm减少到终末随访的(2.1±1.3)mm(t=10.48,P<0.01).患者术前Lysholm膝关节功能评分为(76.7±3.2)分,终末随访时为(95.7±2.4)分(t=7.356,P<0.01). 结论 在关节镜下采用自体半腱肌腱单束解剖重建增强治疗ACL后外侧束部分损伤,能取得良好效果.     

Long term results of anterior cruciate ligament reconstruction with iliotibial tract: 6-, 13-, and 24-year longitudinal follow-up

Many studies have reported successful outcomes less than 10 years after anterior cruciate ligament (ACL) reconstruction. However, longer-term outcomes have not been analyzed. We assessd outcomes 24 years after anterior cruciate ligament reconstruction with iliotibial tract and compared them with shorter-term results in the same patients. Between 1979 and 1981, 45 patients underwent combined intra- and extra-articular ACL reconstruction with iliotibial tract. Follow-up evaluations of these patients were performed at 6, 13, and 24 years after surgery, which included manual and instrumental laxity testing, functional assessments, and radiography. Twenty-six (60%) patients of the original ACL reconstruction cohort participated in all three follow-up assessments. Three patients had undergone meniscectomy prior to ACL reconstruction and 18 underwent meniscectomy together with ACL reconstruction. Eleven patients underwent subsequent meniscectomy. The mean Lysholm score was 96.2, 93.8, and 87.8 at 6-, 13-, and 24-year follow-up, respectively. A significant decrease in mean Lysholm score was found between 13- and 24-year follow-up. The mean KT-1000 side-to-side difference was 3.5 mm at 24-year follow-up. Overall knee laxity did not change significantly during the follow-up period. At 24-year follow-up, 17 (71%) patients had moderate or severe degenerative changes on radiographs although about 50% of the patients participated in regular sports activities and no patient required regular clinical intervention.     

Five-year results of anterior cruciate ligament reconstruction with the Stryker Dacron high-strength ligament

Forty-two consecutive patients (27 male and 15 female, with a mean age of 26 years) suffering from uniflateral chronic anterior cruciate ligament insufficiency underwent surgical reconstruction with a Dacron highstrength ligament (Stryker). In 32 patients the synthetic legament was used as a reinforcement in an iliotibial band intra-articular procedure and in 10 patients as an intra-articular prosthesis without biological reinforcement. There were 24 concomitant injuries such as meniscal tears, status post—meniscectomy or medial collateral ligament insufficiency at the time of reconstruction. The initial injury occurred during soccer in 23 patients and other pivoting sports in 16 patients. Two and 5 years after reconstruction, the patients underwent clinical examination, including the instrumented knee laxity test (OSI), and performed subjective evaluation. The anterior tibial translation was 6.3±2.6mm grater than in the healthy knee, the mean Lysholm score was 78 points, and the Tegner activity score was lower than its pre-injury level. Radiography revealed that 31 of 37 ligaments had ruptured and another 2 ligaments showed more than 5 mm side-to-side increased laxity. The Stryker Dacron high-strength ligament ruptured in more than 80% of the cases and patients could not return to their pre-injury physical performance activities.Supported by grants from the Karolinska Institute     

Evaluation of residual instability after arthroscopic meniscectomy in anterior cruciate deficient knees

Forty-five patients who underwent a partial meniscectomy in an anterior cruciate deficient knee were followed from 2 to 9 years. The average age at the time of the meniscectomy was 28.6 years. The majority of the patients were injured in recreational athletics. The subjects were evaluated preoperatively by a questionnaire and clinical examination, both of which were repeated at followup. The efficacy of the postsurgical rehabilitation was monitored with measurement of quadriceps and hamstring strength on the Cybex Dynamometer. All of the patients had a KT-1000 knee ligament arthrometer test at followup that was compared with the clinical examination. Sixty-five percent of the subjects (13 of 20) with a Lachman and pivot shift of +1 returned to their previous activity level without limitation. Of the patients with a KT-1000 compliance index of 1 mm, 70% (11 of 17) returned to the same athletic level. However, only 20% (2 of 11) of the patients with a clinical instability greater than +1 or a compliance index of 2 mm were able to perform without limitation. The location of the meniscal tear did not correlate with the functional outcome. Six patients required ACL reconstruction.     

Early active extension after anterior cruciate ligament reconstruction does not result in increased laxity of the knee

If permission of full active and passive extension immediately after an anterior cruciate ligament (ACL) reconstruction will increase the post-operative laxity of the knee has been a subject of discussion. We investigated whether a post-operative rehabilitation protocol including active and passive extension without any restrictions in extension immediately after an ACL reconstruction would increase the post-operative anterior–posterior knee laxity (A–P laxity). Our hypothesis was that full active and passive extension immediately after an ACL reconstruction would have no effect on the A–P laxity and clinical results up to 2 years after the operation. Twenty-two consecutive patients (14 men, 8 women, median age 21 years, range 17–41) were included. All the patients had a unilateral ACL rupture and no other ligament injuries or any other history of previous knee injuries. The surgical procedure was identical in all patients and one experienced surgeon operated on all the patients, using the bone-patellar tendon-bone autograft. The post-operative rehabilitation programme was identical in both groups, except for extension training during the first 4 weeks post-operatively. The patients were randomly allocated to post-operative rehabilitation programmes either allowing (Group A, n=11) or not allowing [Group B (30 to −10°), n=11] full active and passive extension immediately after the operation. They were evaluated pre-operatively and at 6 months and 2 years after the reconstruction. To evaluate the A–P knee laxity, radiostereometric analysis (RSA) and KT-1000 arthrometer (KT-1000) measurements were used, range of motion, Lysholm score, Tegner activity level, the International Knee Documentation Committee (IKDC) evaluation system and one-leg-hop test quotient were used. Pre-operatively, the RSA measurements revealed side-to-side differences in Group A of 8.6 mm (2.3–15.4), median (range) and in Group B of 7.2 mm (2.2–17.4) (n.s.). The corresponding KT-1000 values were for Group A, 2.0 mm (0–8.0) and Group B, 4.0 mm (0–10.0) (n.s.). At 2 years, the differences between the two groups were minimal, regardless of the method that had been used. The RSA measurements in Group A were 2.7 mm (0–10.7) and in Group B 2.8 (−1.8 to 9.5). The KT-1000 values were for Group A, 1.0 mm (−1.5 to 3.5), and for Group B, 0.5 mm (−1.0 to 4.0), without any significant differences between the groups. Nor did the Lysholm score, Tegner activity level, IKDC or one-leg-hop test differ. Early active and passive extension training, without any restrictions in extension, immediately after an ACL reconstruction using bone-patellar tendon-bone graft did not increase post-operative knee laxity up to 2 years after the ACL reconstruction.