Intra-operative hamstring tendon graft contamination in anterior cruciate ligament reconstruction

We aimed to evaluate the possibility of hamstring tendon contamination, the correlation with clinical infection and its association with C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) values in 89 anterior cruciate ligament reconstructions. Two tissue samples were obtained for culture from each graft: immediately after harvesting the graft and before implantation. The ESR and the CRP were evaluated preoperatively and on the 4th and 20th postoperative days. Nine patients (10%) had positive cultures but no patient had signs of postoperative infection. All patients had ESR and CRP values elevated at the 4th postoperative day. ESR and CRP values returned to normal levels at the 20th postoperative day. Higher mean values of CRP levels at the 4th day were observed in patients with contaminated grafts compared to those with uncontaminated. Both values reached normal levels at the 20th postoperative day.     

Arthroscopic anterior cruciate ligament reconstruction with periosteum-enveloping hamstring tendon graft

Tendon–bone incorporation of a tendon graft within the bone tunnel is of priority concern when using for anterior cruciate ligament (ACL) reconstruction. Superior healing process and stronger healing strength can be achieved when periosteum is sutured on the tendon inserted into a bone tunnel. We applied this idea to ACL reconstruction for enhancing tendon graft–bone tunnel healing. This is a prospective clinical outcome study with this surgical technique at minimal 2 years follow-up. Periosteum-enveloping hamstring tendon graft has been used in 68 patients. Data from 62 patients who had been followed up completely were analyzed. All patients suffered from a grade 3 or higher grade of Lachman and anterior drawer test with a positive pivot-shift test. Clinical assessments included the Lysholm knee scores, International Knee Documentation Committee (IKDC) scores, KT-1000 instrumented testing, thigh muscle assessment, and radiographic evaluation. The median Lysholm knee score was 59 (40–70) and 94 (60–100) points (P<0.01) before and after surgery. After reconstruction, 81% of patients were able to return to moderate or strenuous activity. Four (6%) patients were found to exhibit grade 2 or more ligament laxity. Complete range of motion could be achieved in 86% of patients. Three patients (5%) had positive pivot shift. Finally, 92% of patients were assessed as normal or nearly normal rating by IKDC guideline. Bone tunnels enlargement of more than 1 mm was identified in 5% of femoral tunnels and 6% of tibial tunnels. The study shows that a satisfactory result can be achieved with the periosteum-enveloping hamstring tendon graft in ACL reconstruction. Periosteum can be easily harvested at the proximal tibia from a routine incision for hamstring tendon harvesting. Besides the potential for improving tendon–bone healing, enveloped periosteum may help to seal the intra-articular tunnel opening in the early postoperative period, and thus avoid synovial fluid reflux into the tunnel. Bone tunnel enlargement could be reduced.     

The effect of intraosseous graft length on tendon-bone healing in anterior cruciate ligament reconstruction using flexor tendon

The current study was performed to understand the relationship between graft length placed within the bone tunnel and intraosseous graft healing in anterior cruciate ligament (ACL) reconstruction. Twenty-four adult beagle dogs were divided into two groups of 12 animals each. In each animal, ACL reconstruction using a 4-mm diameter autogenous flexor tendon graft was done in the left knee. In groups I and II, the graft having a length of 15 and 5 mm, respectively, was placed within the tibial tunnel. The proximal end of the graft was placed through the over-the-top route in all animals. In each group, five animals were sacrificed immediately after surgery, and the remaining seven were sacrificed at 6 weeks postoperatively. Biomechanical and histologic evaluations were performed. In pull out testing, the ultimate failure load and the linear stiffness of the graft-tibia complex harvested at 6 weeks were significantly greater than those harvested at the time-zero period. There were no significant differences in those parameters between groups I and II at 6 weeks. In each group, the perpendicular collagen fibers connecting the tendon to the bone tunnel wall were observed only in the narrow area located close to the intra-articular tunnel outlet. In conclusion, excessively long placement of the flexor graft within the bone tunnel does not result in an additional increase of anchoring strength and stiffness of the graft in ACL reconstruction.     

Graft healing in anterior cruciate ligament reconstruction

Graft healing within the bone tunnel after anterior cruciate ligament (ACL) reconstruction is still a complex, poorly understood biological process that is influenced by multiple surgical and postoperative variables. However, remarkable advances in knowledge of this process have been made based primarly on animal models. According to the findings of this review, some surgical and postoperative variables are known to directly affect time-course and quality of graft-tunnel healing. The type of graft, graft motion, and fixation methods have shown to directly affect time-course and quality of graft-tunnel healing. Therefore, the application of early and aggressive rehabilitation protocols should be cautious when using soft-tissue graft, allografts, and direct or aperture type of fixation for ACL reconstruction. With regard to graft placement, several cadaveric models showed biomechanical advantages of a more anatomical graft location; however, there are no studies that explore the relationship between graft placement and healing process. The precise effect of graft tensioning, graft/tunnel diameter disparity, and graft length within the bone tunnel in the graft healing process remains unclear and requires more research. To enhance graft-tunnel healing, tissue-engineering approaches, including the use of growth factors, mesenchymal stem cells, and periosteum graft augmentation, have been tested on animal models. These have shown promising results in terms of enhancement of bone-graft healing rate.     

The effect of graft-tunnel diameter disparity on intraosseous healing of the flexor tendon graft in anterior cruciate ligament reconstruction

BACKGROUND: Graft-to-tunnel healing is a significant factor in anterior cruciate ligament reconstruction, but there have been few studies on the effect of graft-tunnel diameter disparity on intraosseous healing of the flexor tendon graft. HYPOTHESIS: Graft-tunnel diameter disparity of 2 mm has no effect on the pull-out strength of the graft from the bone tunnel. STUDY DESIGN: Controlled laboratory study. METHODS: Forty-two beagle dogs were divided into three groups. In each animal, reconstruction was performed in the left knee by using a 4-mm diameter autogenous flexor tendon for groups 1 and 2 and by using a 4-mm wide bone-patellar tendon-bone graft in group 3. A 4-mm diameter tunnel was drilled in the tibia of groups 1 and 3 and a 6-mm diameter tunnel, in group 2. In each group, seven animals were sacrificed at 3 and 6 weeks. RESULTS: The perpendicular fibers connecting the graft to the bone were generated in groups 1 and 2, and the number appeared to be higher in group 2, where the space was greater. There was no significant difference in the ultimate failure load between groups 1 and 2 at each period. CONCLUSION: Graft-tunnel diameter disparity of up to 2 mm may not adversely affect intraosseous healing of the flexor tendon graft. CLINICAL RELEVANCE: Surgeons need not be overly concerned about minor graft-tunnel diameter disparities.     

Effect of graft tensioning on mechanical restoration in a rat model of anterior cruciate ligament reconstruction using free tendon graft

Purpose

Initial graft tensioning is important in anterior cruciate ligament reconstruction (ACLR), but its effect on graft healing is still not clear. Since all previous animal studies on graft tensioning used bone–patellar tendon–bone, this study aimed to investigate the effect of initial graft tensioning on ACLR using tendon graft.

Methods

Fifty-five Sprague–Dawley rats underwent ACLR using flexor digitorum longus tendon graft. A constant force of 2 or 4 N was applied during graft fixation. At 0, 2, and 6 weeks, knee samples were harvested (n = 6) for static knee laxity test and graft pull-out test. Histological examination was performed at 2 and 6 weeks post-injury (n = 4).

Results

At time zero, knee laxity was restored by ACLR with 2 or 4 N tensioning as compared to ACL-deficient group (p < 0.001), and the 4 N group exhibited a better restoration as compared to 2 N group (p = 0.031). At week 2 post-operation, the 4 N group still exhibited a better restoration in knee laxity (p = 0.001) and knee stiffness (p = 0.002) than the 2 N group; the graft pull-out force (p = 0.032) and stiffness (p = 0.010) were also higher. At week 6 post-operation, there was no significant difference between the 2 and 4 N group in knee laxity and graft pull-out strength. Histological examination showed that the beneficial effect of higher initial graft tension may be contributed by maintenance of graft integrity at mid-substance and reduction in adverse peri-graft bone changes in the femoral tunnel region.

Conclusions

A higher initial graft tension favours the restoration of knee laxity and promotes graft healing in ACLR using free tendon graft in the rat model.     

MR imaging of anterior cruciate ligament reconstruction graft

OBJECTIVE. The objective was to determine the MR imaging findings that differentiate intact anterior cruciate ligament reconstruction graft, partial-thickness tear, and full-thickness tear, using arthroscopy as the gold standard. MATERIALS AND METHODS. Sixteen consecutive MR imaging examinations were retrospectively and independently evaluated by two musculoskeletal radiologists for primary signs (graft signal, orientation, fiber continuity, complete discontinuity, and thickness) and secondary signs (anterior tibial translation, uncovered posterior horn lateral meniscus, posterior cruciate ligament hyperbuckling, and abnormal posterior cruciate ligament line) of anterior cruciate ligament reconstruction graft tear in 15 patients with follow-up arthroscopy. Results were compared with arthroscopy, and both receiver operating characteristic curves and kappa values for interobserver variability were calculated. RESULTS. Arthroscopy revealed four full-thickness graft tears, seven partial-thickness tears, and five intact grafts. Of the primary signs, graft fiber continuity in the coronal plane and 100% graft thickness in the sagittal or coronal plane were most valuable in excluding full-thickness tear. Complete discontinuous graft in the coronal plane also was valuable in diagnosis of full-thickness tear. Of the secondary signs, anterior tibial translation and uncovered posterior horn lateral meniscus assisted in differentiating graft tear (partial or full thickness) from intact graft. The other primary and secondary signs were less valuable. Kappa values were highest for graft fiber continuity and graft discontinuity in the coronal plane. CONCLUSION. Full-thickness anterior cruciate ligament graft tear can be differentiated from partial-thickness tear or intact graft by evaluating for graft fiber continuity (coronal plane), complete graft discontinuity (coronal plane), and graft thickness (coronal or sagittal plane).     

Effects of graft pretensioning in anterior cruciate ligament reconstruction

Purpose

Graft pretensioning is used in anterior cruciate ligament (ACL) reconstruction to prevent secondary slackening. Its effects on collagen fibrillar ultrastructure are not known. In this study, we hypothesized that graft pretensioning in ACL reconstruction creates ultrastructural changes detectable in scanning electron microscopy (SEM).

Methods

A prospective comparative study was carried out on 38 ACL reconstructions using a 4-strand semitendinosus graft. Samples were harvested intra-operatively before and after pretensioning for 30?s, 2 or 5?min. The images produced in SEM were analyzed using an original semi-quantitative ?CIP? score taking into account collagen cohesion, integrity, and parallelism. Intra- and inter-tester reliability for the CIP score were tested.

Results

The CIP scores decreased by 3.5 (1.6) points after pretensioning (P?P?Conclusion Pretensioning ACL grafts resulted in alteration of the collagen fibrillar ultrastructure, detectable using SEM. These results confirm the existence of collagen ultrastructural changes after pretensioning that may be related to its duration.

Level of evidence

Prospective comparative study, Level II.     

富血小板血浆凝胶在同种异体肌腱重建前交叉韧带后腱-骨愈合中的作用

目的 观察富血小板血浆(platelet-rich plasma,PRP)凝胶对同种异体跟腱重建兔前交叉韧带(ACL)后腱一骨愈合的影响.方法 24只兔行双侧ACL重建;一侧膝关节移植物予自体PRP凝胶预处理(实验组),另一侧膝关节移植物不予处理(对照组).于术后2,6和12周行组织学、免疫组化和生物力学评价.结果 2周和6周时Burak评分实验组高于对照组.12周时对照组腱-骨界面为成熟瘢痕组织,而实验组显示该界面为成熟纤维软骨带.免疫组化显示实验组血管内皮生长因子(VEGF)的阳性表达在早期较对照组高,TGF-β1的表达持续高于对照组.生物力学分析显示2周及6周时实验组极限负荷[(15.3±2.9)N、(33.2±6.9)N]明显高于对照组((7.9±1.4)N、(23.7±4.9)N](P＜0.05).结论 PRP凝胶可促进同种异体移植肌腱早期腱-骨愈合.     

Change in the cross-sectional area of a patellar tendon graft after anterior cruciate ligament reconstruction

The purpose of this study was to clarify the change in the cross-sectional area (CSA) of a patellar tendon graft after anterior cruciate ligament (ACL) reconstruction, and its relationship with postoperative knee laxity. Forty patients (25 men and 15 women) were included in this study. Intraoperative CSA measurements were performed with an instrumented areamicrometer, while a magnetic resonance imaging (MRI) evaluation was utilized for the assessment postoperatively. For intraoperative measurement, the average CSA of a 10-mm wide patellar tendon graft was 32.3 ± 7.0 mm², while the average CSA measured at follow-up (mean: 14.8 months) was 48.8 mm², showing a significant mean increase ratio of 49.4%. This value corresponded to 115% of the native ACL. The average CSA measured in 30 patients at 6 months was 49.7 mm², almost equal to the value at the final follow-up (49.8 mm²) in the same patient group. Among potentially influential factors, postoperative notch width (available space for the ACL graft) had significant correlation with the CSA of the graft at follow-up. Finally, both intra- and postoperative CSA values did not correlate with postoperative knee laxity, indicating that a bigger graft does not guarantee a better laxity.     

Knee isokinetic performance following anterior cruciate ligament reconstruction: patellar tendon versus hamstrings graft

Objective: To compare knee isokinetic performance six months after reconstruction of the anterior cruciate ligament using grafts from either the patellar tendon or the hamstrings among patients who underwent the same rehabilitation protocol.

Methods: Thirty-four patients were evaluated (17 with grafts from the patellar tendon and 17 with grafts from the hamstrings). Operated and non-operated knees were compared with regards to the variables of peak torque, work and the hamstring/quadriceps relationship at velocities of 60º/s and 180º/s and power of 180º/s after six months of surgery.

Results: The patients with ACL reconstruction using the patellar tendon (BPTB) showed quadriceps deficits for all variables, but the flexor musculature was balanced. In the hamstring group, both the extensors and the flexors showed deficits for the variables analyzed, except for hamstring power at 180º/s.

Conclusion: Patients in the patellar tendon group had a greater quadriceps deficit compared with those in the hamstrings group. Patients in the hamstrings group had a greater muscular deficit in the flexor mechanism compared with the contralateral knee. An unbalanced H/Q ratio was observed regardless of graft type, but this was more evident in the BPTB group.     

Early post-operative morbidity following anterior cruciate ligament reconstruction: patellar tendon versus hamstring graft

This study documented postoperative morbidity during the first 4 months following anterior cruciate ligament (ACL) reconstruction using either patellar tendon or hamstring tendon autograft. Sixty-five patients undergoing primary arthroscopically assisted single-incision ACL reconstruction were randomized to have a central third bone patellar tendon bone autograft (PT) or a doubled semitendinosus/doubled gracilis autograft (HS). Postoperatively patients undertook a standard 'accelerated' rehabilitation protocol. Patients were reviewed after 2 weeks, 8 weeks, and 4 months. At each review the location and severity of general knee pain and the presence and severity of anterior knee pain (AKP) were recorded as were the presence and size of an effusion as well as the active and passive flexion and passive extension deficits compared to the contralateral limb. Pain on kneeling, KT-1000 measured side to side difference in anterior tibial displacement, isokinetic assessment of quadriceps and hamstring peak torque deficits, IKDC score and Cincinnati sports activity level were also recorded after 4 months. After 2 weeks more patients in the PT group complained of AKP and reported that the pain was more severe. After 8 weeks there was no significant difference between the groups for any variable. After 4 months the severity of general pain experienced and the incidence of pain on kneeling were greater in the PT group. The PT group also demonstrated a significantly greater quadriceps peak torque deficit at 240 degrees /s. IKDC scores were higher in the HS group, but Cincinnati sports activity scores were higher in the PT group. Although we observed a lower morbidity in the HS group, primarily related to pain, the severity of pain in both groups was relatively low and, in light of the higher mean sports activity level observed in the PT group at 4 months the clinical impact of the difference may not be significant.     

关节镜下自体髌腱移植重建前交叉韧带的疗效观察

目的探讨使用自体骨-1/3髌腱-骨移植重建损伤的前交叉韧带(ACL)的临床疗效。方法本研究包括40例单纯性前交叉韧带断裂伴症状性胫骨前脱位的病例,均采用自体骨-1/3髌腱-骨重建。术后进行为期6个月的康复训练。术前和术后随访时行患侧膝关节X线检查,行体格检查及功能评分。结果总共36例(90%)获得随访,时间平均31个月。30例(83%)Lachman征及旋转移位试验阴性。Lysholm评分由术前平均(55.7±3.1)分增加至术后最后一次随访时的(90.1±2.7)分(P0.001)。而Tegner评分则由术前平均(5.0±1.4)分增加至术后(6.25±1.2)分(P0.001)。与术前X线检查相比,无退行性改变。结论采用自体骨-1/3髌腱-骨重建前交叉韧带后2年以上随访结果发现,83%的患者膝关节不稳现象消失,至术后最后一次随访时膝关节功能评分较术前显著增加。以该方法重建ACL有效地恢复了受伤膝关节功能。     

Extensor mechanism function after patellar tendon graft harvest for anterior cruciate ligament reconstruction.

We evaluated extensor mechanism function in 10 patients after they had arthroscopically assisted ACL reconstruction using the central third of the patellar tendon. The patients were randomly selected 12 to 24 months after reconstruction. All had rehabilitation where range of motion was initiated within the 1st postoperative week. All patients stated that they were satisfied and considered their knee to be stable. The KT-1000 maximum measurements (30 to 40 pounds) averaged an increase of 1.7 mm when compared with the opposite knee. Subjective complaints, such as anterior knee pain, grating, and weakness, were common and only 3 of 10 patients returned to all of their preinjury sports. Persistent radiographic abnormalities were common. Physical examination and functional testing also revealed persistent dysfunction of the extensor mechanism in patients with radiographic abnormalities. Isokinetic testing at 60 deg/sec showed an average quadriceps deficit of 18% compared to the normal extremity. Axial computed tomography scans revealed significant decrease in quadriceps cross-sectional area. Magnetic resonance imaging and computed tomography confirmed persistent defects at the harvest site; there was significant anterior knee scar formation in these patients. Despite achieving ligamentous stability, patients still experienced permanent weakness, functional deficits, patellar chondrosis, and pain after ACL reconstruction using the central one-third of the patellar tendon.     

Central quadriceps free tendon for anterior cruciate ligament reconstruction

Central quadriceps free tendon provides an outstanding autograft alternative for routine anterior cruciate ligament (ACL) reconstruction, allowing preservation of hamstring tendons and eliminating the morbidity of bone plug harvest from the patella. Correct graft harvest technique, proper tunnel/graft sizing, accurate fixation, and adherence to the methods described will permit excellent ACL reconstruction with low morbidity.     

前交叉韧带重建术后假体功能不全的影像评价

目的 探讨前交叉韧带重建术后假体功能不全的影像特点.方法 同顾性分析24例韧带重建术后因功能不全而接受二次关节镜的患者,包括16例假体断裂,8例假体松弛.影像评价包括骨道关节内口的位置、韧带假体的MRI表现、骨关节病程度及相关并发症.假体断裂组和松弛组的骨道内口位置、MRI表现为断裂的比例及骨关节病等的比较,采用Fisher精确概率法比较.结果 断裂组中,2例股骨骨道关节内口位置异常,3例胫骨骨道关节内口位置异常;松弛组中,3例股骨骨道关节内口位置异常,4例胫骨骨道关节内口位置异常.两组间比较,股骨骨道关节内口位置异常(P=0.289)和胫骨骨道关节内口位置异常的比例(P=0.167)差异均无统计学意义.断裂组中,MRI正确诊断15例完全断裂,1例部分断裂表现为正常;松弛组中,4例表现为正常,其余4例在MRI上被诊断为假体断裂.两组在MRI上表现为断裂的比例差异存在统计学意义(P =0.028).断裂组中,14例可见骨关节病;松弛组中,5例可见骨关节病.两组骨关节病的比例差异无统计学意义(P=0.289).结论 假体断裂和假体松弛骨道关节内口位置异常和骨关节病的比例差异无统计学意义;MRI可以正确诊断绝大多数假体断裂,而部分假体松弛则容易被误诊为假体断裂.