Augmentation of anterior cruciate ligament reconstruction in dogs with prostheses of different stiffnesses

The purpose of this study was to investigate the biological and biomechanical properties of anterior cruciate ligament (ACL) reconstruction augmented with Dacron prostheses of three different stiffnesses. The ACLs of 36 adult mongrel dogs were removed and the ligament was reconstructed. In 18 dogs, one knee was reconstructed with patellar tendon alone, and the contralateral knee with Dacron augmented patellar tendon. In the remaining 18 dogs, reconstruction was with Dacron augmented patellar tendon with Dacron alone being used for the contralateral control knee. Death was 3 months after surgery, and the reconstructions were examined biologically and biomechanically. The mechanical data were compared with immediate postoperative data obtained from 45 reconstructed fresh cadaveric knees. Tensile testing demonstrated that an increase in failure load was found when the implanted patellar tendon graft was compared with the cadaveric reconstruction. The strength of the Dacron augmented reconstruction showed little change while the Dacron alone graft decreased in strength during the period of implantation. No clear difference was found between the performance of augmentation devices of different stiffnesses. Microangiography showed that grafts were totally revascularized in patellar tendon alone, but not well revascularized in Dacron augmented patellar tendon and Dacron alone reconstruction. The presence of the Dacron appeared to have an adverse effect on revascularization.     

A method of repair for quadriceps tendon or patellar ligament (tendon) ruptures without cast immobilization. Preliminary report

The quadriceps tendon and patellar tendon (ligament) were repaired with a Dacron vascular graft used as a tension suture material. In cases of quadriceps tendon ruptures, the Dacron graft is passed transversely through the patellar ligament just below the patella and crossed transversely at the level of the musculotendinous junction with two loops applying tension to the tendon, which brings the tendon ends together by creating a solid structure. In cases of patellar ligament ruptures, the Dacron graft is passed through a hole in the tibia posteriorly to the tibial tuberosity instead of through the patellar ligament below the patella. This technique enables early mobilization on the first day after surgery. The technique was first tested on six dogs with severed quadriceps tendons and patellar ligaments that were repaired with this suture method. All of the animals recovered from surgery and walked and ran normally on the repaired legs within 27 days and with only mild limping after 17 days. The technique was then used on six patients, four with complete quadriceps tendon rupture and two with complete tear (avulsion) of the patellar ligament (tendon). In all of the patients, excellent surgical results were obtained and leg immobilization was virtually eliminated. Physical therapy was prescribed the first day after surgery. The rehabilitation period was significantly reduced.     

Research on strength of the grafts that are used in anterior cruciate ligament reconstruction]

Reconstruction of the anterior cruciate ligament (ACL) using autogenous tissue is a frequently performed procedure used to restore functional stability in ACL--deficient knees. The purpose of this study was to determine the structural mechanical properties of the ACL and the grafts that are used in anterior cruciate ligament reconstruction. We tested specimens of human tissue including: ACL, medial third patellar tendon B-PT-B, central third patellar tendon B-PT-B, gracilis tendon, semitendinosus tendon (single-stranded, double-stranded and quadrupled-stranded), distal iliotibial tract and plantaris tendon (single-stranded and double-stranded). Specimens were obtained at autopsy from 32 young male cadavers. Biomechanical tests were performed using the FPZ-100 machine (produced by VEB Rauenstein). The following grafts have shown higher values than ACL: quadrupled semitendinosus--229% of ACL, doubled semitendinosus--130% of ACL, central third patellar tendon B-PT-B--114% of ACL and medial third patellar tendon B-PT-B--107% of ACL. The following grafts have shown lower values than ACL: semitendinosus tendon--72% of ACL, gracilis tendon--49% of ACL, distal iliotibial tract--47% of ACL, doubled plantaris--18% of ACL and single plantaris--10% of ACL.     

内侧髌股韧带重建术治疗复发性髌骨脱位的疗效研究

目的探讨游离肌腱移植重建内侧髌股韧带的手术方法及治疗复发性髌骨脱位的疗效。方法自2006年6月至2012年7月收治复发性髌骨脱位患者共40例（47膝）,男10例（12膝）,女30例（35膝）,年龄7～51岁,平均19．4岁。全部经膝关节镜检最后确诊,其中43膝采用游离自体半腱肌,4膝采用异体肌腱,通过髌骨双隧道移植重建内侧髌股韧带,镜下动态调整移植肌腱的张力,使髌股关节对合达到正常,并用挤压螺钉将肌腱游离端固定在股骨止点。其中8例（10膝）同时行髌韧带止点内移术。结果有36例（42膝）患者获得随访,随访时间3—70个月,平均随访23个月。临床疗效评价包括髌骨主观稳定性评估、Lysholm膝关节评分及Insall疗效标准（1976年）。术后髌骨外推试验和恐惧试验均为阴性。手术前后Lysholm评分术前平均为（63．1±9．1）分,术后评分为（87．1±6．4）分,手术前后的差异有统计学意义（t=21．7,P〈0．05）。按Insall疗效标准,优良率为85．7％。结论采用以游离肌腱重建MPFL为主的综合术式治疗复发性髌骨脱位,手术效果满意。     

Arthroscopic transtibial single-bundle posterior cruciate ligament reconstruction using patellar tendon graft compared with hamstring tendon graft

Purpose

The purpose of this study was to compare the outcomes of arthroscopic transtibial single-bundle posterior cruciate ligament reconstruction using autologous patellar tendon and hamstring tendon grafts.

Methods

From 1998 to 2007, 59 patients with symptomatic isolated posterior cruciate ligament injury were included in this retrospective study. Twenty-five knees were reconstructed using bone-patellar tendon-bone graft, and 34 knees were reconstructed using hamstring graft. In both groups, surgical techniques were similar, except material of fixation screws. Patients were evaluated pre-operatively and post-operatively at the latest follow-up with several parameters, including symptoms, physical examination, outcome satisfaction, functional scores, radiography and complications.

Results

Average follow-up period was 51.6 months in patellar tendon group and 51.1 months in hamstring tendon group. Significantly more kneeling pain (32 vs. 3 %), squatting pain (24 vs. 3 %), anterior knee pain (36 vs. 3 %), posterior drawer laxity and osteoarthritic change were shown in patellar tendon group than in hamstring tendon group post-operatively. No significant differences were found in other parameters between both groups.

Conclusions

Several shortcomings, including anterior knee pain, squatting pain, kneeling pain and osteoarthritic change, have to be concerned when using patellar tendon autograft. In conclusion, hamstring tendon autograft may be a better choice for transtibial tunnel PCL reconstruction.     

The comparison of functional results of anterior cruciate ligament injuries treated with semitendinosus tendon and central one-third of patellar tendon autografts

The results of ACL reconstructions with autologus grafts taken from semitendinosus tendon and patellar ligament are presented. There were 78 patients in four groups. Patient age ranged from 15 to 47 years. The period of observation varied from 1 to 10 years, average 3.5. The first group consisted of 28 people treated with single semitendinosus tendon graft. In the second group there were 12 patients with acute ACL injuries treated by reinsertion of torn ligament attachment augmented by semitendinosus tendon. The third group of 18 persons had an ACL reconstruction with central one-third of patellar ligament fastened with thread loops on bone screws or staples. The last group of 20 patients had ACL reconstruction with central one-third of patellar ligament autograft. All patients were prospectively evaluated according to the Hospital for Special Surgery and the Lysholm and Gillquist scales. The statistical analysis clearly reveals the best results in the fourth group of patients, who had graft fixation with interference screws. Received: 4 April 2001/Accepted: 23 April 2001     

Nerve regeneration during patellar tendon autograft remodelling after anterior cruciate ligament reconstruction: An experimental and clinical study

The innervation of the rat and human anterior cruciate ligament, patellar tendon, and patellar tendon autograft after reconstruction of the anterior cruciate ligament was investigated by immunohistochemical and histological methods. A rat model of reconstruction with patellar tendon autograft was evaluated during active graft remodelling (2–16 weeks) and compared with normal ligament and tendon. The knees of 10 patients who had undergone reconstruction with patellar tendon autograft were examined 5–37 months postoperatively (remodelling fully completed) with arthroscopy and biopsy. As a control, biopsies from normal ligament and tendon were obtained from four patients. Nerve fibers were identified using antisera for protein gene product 9.5, a general neural marker. Neuronal regeneration was assessed by the expression of growth-associated protein 43/B-50. The sensory type of innervation was characterized by assessing the distribution of nerves containing the sensory neuropeptides calcitonin gene related peptide and substance P. Immunoreactivity for all neural markers was found in both rat and human anterior cruciate ligament and patellar tendon. Two weeks after reconstruction, the rat autograft was acellular and no innervation could be identified. After 4 weeks, the grafts were viable, and immunoreactivity for protein gene product 9.5, growth associated protein 43/B-50, and calcitonin gene-related peptide was found until the 16th week postoperatively. Immunoreactivity for substance P was found in rat autografts at 4 weeks postoperatively only. All biopsies of human patellar tendon autograft showed signs of the remodelling process being fully completed, with revascularization and a sinusoidal collagen pattern with fibroblast repopulation. Neuropeptide immunoreactivity, however, was not found. The presence of immunoreactivity to sensory neuropeptides in the anterior cruciate ligament and patellar tendon may indicate a nociceptive and neuromodulatory function of these structures. The expression of sensory neuropeptides in the rat patellar tendon autograft suggests a possible involvement of sensory innervation during healing of the graft.     

Arthroscopic anterior cruciate ligament reconstruction with quadriceps tendon composite autograft

At present, no single graft option clearly outperforms another. Autografts (patellar tendon, hamstring) and allografts (Achilles tendon, patellar tendon) are the grafts most often used. However, each grafts has advantages and disadvantages. Quadriceps tendon graft for anterior cruciate ligament reconstruction is not new, but an alternative composite graft is introduced here that consists of quadriceps tendon–patellar bone and bone obtained from a coring reamer used to create the tibial tunnel. This composite graft retains reduced morbidity while allowing the secure bone-to-bone fixation associated with bone–patellar tendon–bone graft.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 5 (May-June), 2001: pp 546–550     

A new technique of harvesting patellar tendon autografts for anterior cruciate ligament reconstruction.

A new surgical technique to uniformly harvest the middle one-third of the patellar tendon for anterior cruciate ligament reconstruction is described. The technique uses a guide system of 8 templates of varying widths to guide the saw cuts and "collared," depth-controlled saw blades and drill bits to produce a standard cutting and drilling depth. This kind of template system lessens the risks of graft harvesting complications such as patella fracture, bone graft fragmentation, suture pull out, and judgment errors pertaining to graft depth, length, or width. The Patellar Tendon Graft Guide was used to obtain a patellar tendon graft in 65 patients. Fifty-nine arthroscopic-assisted and 6 open anterior cruciate ligament reconstructions were performed. Of the 65 grafts harvested, 63 consistently demonstrated bone portions 20 mm in length, 7 mm in depth, and a width corresponding to the template chosen (usually 10 mm). Two grafts supposed to be 10 mm in width turned out to be 9 mm in width because of a technique related problem.     

The morphological effects of synthetic augmentation in posterior cruciate ligament reconstruction

The treatment of posterior cruciate ligament (PCL) injuries remains controversial. Due to various problems, PCL reconstruction has not consistently produced the knee stability desired. Biological graft tissue undergoes a remarkable healing process comprising different phases. The strength of autogenous graft material decreases soon after operation. During this early healing phase synthetic augmentation could protect the graft tissue from overloading or overstretching, supporting the tissue revitalization and remodeling process. In order to evaluate the morphological effects of the ligament augmentation device (LAD) on a free patellar tendon autograft in PCL reconstruction, a comparative study in sheep was conducted. In 24 mature sheep, the PCL was replaced with either a patellar tendon autograft alone or a patellar tendon autograft augmented by the LAD. The LAD was fixed at both ends. After the operation the animals were not immobilized. Tibial fixation was released 8 weeks postoperation. The autografts of both groups were histologically evaluated after 2, 6, 16, 26, 52, and 104 weeks. In addition to necrotic and degenerative alterations, a remarkable inflammatory reaction could be seen in the LAD-augmented autografts early postoperation. Compared with the nonaugmented autografts, tissue formation and remodeling were delayed in the augmented group. After 1 and 2 years, the morphology of the autograft tissue was similar in both the augmented and nonaugmented group and differed from that of a normal PCL. The LAD was surrounded by a chronic inflammatory reaction, and collagen fiber ingrowth into the LAD was not observed. Using transmission electron microscopy, small diameter collagen fibrils were predominant in the graft tissue of both groups. Thus, a better remodeling of the autograft tissue in the presence of the LAD could not be demonstrated in this particular study. The value of synthetic augmentation of biological grafts in PCL reconstruction seems to be questionable at present.Supported by the Deutsche Forschungsgemeinschaft     

Biomechanical study of ACL reconstruction grafts

There are no published studies describing the strength quadrupled gracilis tendon alone and quadrupled semitendinosus tendon alone in the configuration used for anterior cruciate ligament (ACL) reconstruction. The primary objective was to compare the mechanical properties of grafts used for ACL reconstruction during a tensile failure test. The secondary objective was to evaluate the effect of uniform suturing on graft strength. Fifteen pairs of knees were used. The mechanical properties of five types of ACL grafts were evaluated: patellar tendon (PT), sutured patellar tendon (sPT), both hamstring tendons (GST4), quadrupled semitendinosus (ST4), and quadrupled gracilis (G4). Validated methods were used to perform the tensile tests to failure and to record the results. Student's t‐test was used to compare the various samples. The maximum load to failure was 630.8N (± 239.1) for the ST4, 473.5N (± 176.9) for the GST4, 413.3N (± 120.4) for the sPT, and 416.4N (± 187.7) for the G4 construct. Only the ST4 had a significantly higher failure load than the other grafts. The sPT had a higher failure load than the PT. The ST4 construct had the highest maximum load to failure of all the ACL graft types in the testing performed here. Uniform suturing of the grafts improved their ability to withstand tensile loading. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1188–1196, 2015.     

Histological and biochemical analysis of the fibrous tissue induced by implantation of synthetic ligament (Dacron): An experimental study in a rat model

We conducted a comparative study to evaluate the quality and true nature of the fibrous tissue formed around synthetic grafts when used in ligament replacement. In one group of Lewis rats, a patellar ligament was replaced with a Dacron prosthesis; the comparison group received a tail tendon isograft. Two-, 4-, 8-, 12-, and 24-week comparisons showed histological and biochemical changes in the Dacron group alone that were consistent with foreign-body reaction. Specifically, the Dacron group showed infiltration by large numbers of macrophages and foreign-body, multinucleated giant cells. In addition, the capsule of fibrous tissue that developed around the Dacron ligaments was characterized by lower collagen solubility, a higher content of noncollagenous protein, and a higher proportion of type III collagen than that comprising the isografted tendons. The results of this study call into question the suitability of synthetics for ligament replacement.     

ACL reconstruction using an abnormally thick autogenous patellar tendon graft.

This prospective study measured the patellar tendon thickness of 543 patients who underwent anterior cruciate ligament (ACL) reconstruction with an autogenous bone-patellar tendon-bone graft to document the normal range of patellar tendon thickness and to determine if using thicker than normal patellar tendons as an ACL graft source affected postoperative outcome. The postoperative results of 55 patients who underwent ACL reconstruction with a patellar tendon > or =7 mm thick (thick tendon group) were compared with those of 488 patients who underwent ACL reconstruction with a patellar tendon < or =6 mm thick (normal tendon group). 5 mm (4.5 mm in women and 5.3 mm in men) with a range of 3-11 mm (3-7 mm in women and 3-11 mm in men). There was no statistically significant difference in the postoperative KT-1000 arthrometer mean manual maximum difference (2.0 mm for grafts < or =6 mm thick and 1.9 mm for grafts > or =7 mm thick), postoperative quadriceps muscle strength scores, modified Noyes questionnaire subjective scores (mean of 91 points for grafts < or =6 mm thick and 92 points for grafts > or =7 mm thick), or postoperative stability and pain scores. These results indicate that an abnormally thick patellar tendon should not preclude the use of this involved tendon as a graft source for ACL reconstruction.     

RETRACTED ARTICLE: The effect of graft choice on functional outcome in anterior cruciate ligament reconstruction

A prospective, randomised, 5-year follow-up study was designed to compare the functional results between patellar tendon and hamstring tendon autografts after anterior cruciate ligament reconstruction. Primary reconstruction was performed in 32 patients using the central third of the patellar ligament and in 32 patients using double-looped semitendinosus and gracilis tendons. All reconstructions were performed by a single surgeon, with identical surgical technique and rehabilitation protocol. Of the total 64 patients in the study, 54 (85%) were available for the 5-year follow-up. No statistically significant differences were seen with respect to Lysholm score, International Knee Documentation Committee (IKDC) classification, clinical and KT-2000 arthrometer laxity testing, single-legged hop test and anterior knee pain. Graft rupture occurred in two patients (8%) in the patellar tendon group and in two patients (7%) in the hamstring tendon group; 23 patients (88%) in the patellar tendon group and 23 patients (82%) in the hamstring tendon group returned to their pre-injury activity level. Good subjective outcome and stability can be obtained by using either graft; no statistically significant differences were found in functional outcome between the grafts.     

A biomechanical analysis of four different methods of harvesting bone-patellar tendon-bone graft in porcine knees

BACKGROUND: Anterior cruciate ligament reconstruction with use of bone-patellar tendon-bone graft is commonly performed to treat functional instability of the knee after injury of the anterior cruciate ligament. Patellar fracture is an underreported complication of this procedure, yet it may be a career-ending injury for a professional athlete. The purpose of this study was to design a new technique to procure the patellar bone plug when reconstructing the cruciate ligament with use of patellar tendon. METHODS: Fifty-eight knees were harvested from eighteen to twenty-four-month-old pigs. Bone plugs of four geometrical shapes were cored out of the patellae from forty knees (four plug shapes for each of ten knees). Ten knees had no graft removed. Fifty knees were tested for the effects of a single impact. Eight knees (two plug shapes for each of four knees) were tested for the effects of repeated impacts. Data were analyzed statistically with use of an ordinal logistic model. The probability of impact failure of the patella at different energy levels was calculated. RESULTS: Impact energy has been shown to have a significant effect on the outcome (p < 0.001). When controlling for energy level, there was a significant difference between the sharp and round corners (p < 0.01). The ordinal logistic model was found to be very good for predicting the outcome of impact testing. The impact energy required to create a 1% probability of complete fracture was 7 J for a patella with a sharp-cornered plug defect, 17 J for a patella with a trapezoidal plug, 22 J for a patella with a sharp-cornered defect with a drill-hole at the corner, 40 J for a patella with a round-cornered defect, and about 49 J for a normal patella. Repeat impact testing substantially damaged the patellae with sharp-cornered defects, as they failed earlier at a lower energy and after a lower number of impacts than did the patellae with round-cornered defects. CONCLUSIONS: We propose the use of the round-cornered patellar bone plug when bone-patellar tendon-bone graft is harvested for anterior cruciate ligament reconstruction, to further reduce the small likelihood of a patellar fracture occurring intraoperatively or in the early postoperative rehabilitation phase.     

Patellarsehnenruptur 10 Jahre nach vorderem Kreuzbandersatz durch Patellarsehnen-Knochen-Transplantat

Autologous transplantation of the central third of the patella tendon with a bone-patellar tendon-bone (BTB) graft is one of the most commonly used techniques for anterior cruciate ligament (ACL) reconstruction. Frequently chosen alternative sources include semitendinosus and gracilis tendon autografts. The differences of opinion regarding graft sources mainly result from comparison of outcome and complications. Although higher donor site morbidity and postoperative extensor mechanism complications are postulated for bone-patellar tendon-bone grafts, patellar tendon ruptures following anterior cruciate ligament reconstruction are rarely reported in the literature. These predominantly occur during the early postoperative period. We present the case of a patellar tendon rupture in a healthy 36-year-old man, who suffered a skiing accident 10 years after uneventful ACL reconstruction with a BTB graft.     

Operative management of acute PCL injuries with associated pathology: long-term results.

Eighteen consecutive patients with posterior cruciate ligament injury and associated pathology were reviewed. All were re-examined with an average follow up of 5.4 years (range: 3.5 to 7.5). Six posterior cruciate ligaments were repaired to the femur with multiple #2 nonabsorbable suture, and one "mop end" mid-substance tear was repaired with sutures in each stump. Seven mid-substance tears were repaired and augmented with the semitendinosus tendon, while four additional mid-substance tears were repaired and augmented with the semitendinosus tendon and a Dacron stent (Meadox). One medial meniscus was repaired and one was partially excised, and one lateral meniscus tear was partially excised. The anterior cruciate ligament was repaired to the tibia in two knees, left alone (interstitial tear) in two, and excised with extraarticular iliotibial band tenodesis augmentation in five. At follow up, arthrometer readings (Stryker) correlated well with clinical examination. The four knees with Dacron stent had a 0 to 1 mm difference at 90 degrees, while the failures had greater than 5 to 6 mm. Six of these were in the repair alone group and two were in the repair with semitendinosus augmentation group. Eight knees (44.5%) had radiographic changes primarily in the medial compartment. Using Hughston's perimeters to evaluate the results, objective 55.5% were rated good, 27.8% were rated fair, and 16.7% were rated poor or failures. Using Clancy's criteria, 22.2% were excellent, 22.2% were good, 44.5% were fair, and 11.1% were rated failures.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of tibial tunnel dilation on pullout strength of semitendinosus-gracilis graft in anterior cruciate ligament reconstruction

This biomechanical cadaver study evaluated the effect of tibial tunnel dilation on the pullout strength of semitendinosus and gracilis tendon grafts in anterior cruciate ligament reconstruction. Fourteen grafts were harvested, and the anterior cruciate ligament was reconstructed in the tibial and femoral tunnels. All femoral tunnels were reamed to the diameter of the graft. In seven knees, the tibial tunnels were reamed to the diameter of the graft. In the remaining seven knees, the tibial tunnels were reamed 2 mm smaller than the diameter of the graft and then serially dilated to the graft size using cannulated smooth dilators. Mechanical testing to graft failure was conducted. All grafts failed by graft pullout from the tibial tunnel. However, mean peak load was significantly higher for the dilated tibial specimens (616 +/- 263 N) than for the reamed specimens (453 +/- 197 N) (P = .0025).     

Response of hamstring and patellar tendon grafts for anterior cruciate ligament reconstruction during cyclic tensile loading

The efficacy of anterior cruciate ligament (ACL) reconstruction in the knee using hamstring tendon or patellar tendon grafts is thought to depend on the relative amounts of graft elongation, or creep, following postoperative rehabilitation. In this study, the creep responses of the tendinous portions of these two graft types were compared during 1 hour of cyclic loading to 200 N at 1 Hz. In the hamstring tendon grafts, strains were measured in both the tissue and in the length-augmentation tape to identify the relative contribution of this particular graft fixation to overall creep. Differences in tissue strain between graft types during cyclic loading were not statistically significant. For both types of grafts, overall graft length significantly increased after 3600 cycles while tissue creep was not significant. The greatest creep in the hamstring tendon grafts occurred at the tissue-tape interface, indicating a potential disadvantage of this composite graft construct.     

Differenzierte Transplantatauswahl in der Kreuzbandchirurgie

Over the past century numerous graft materials have been used for the reconstruction of the cruciate ligament of the knee. Among the autologous tissues that are currently recommended as graft materials, the central bone patellar tendon bone graft, a quadrupled hamstring graft and the central quadriceps tendon graft have the greatest clinical significance. With some limitations, allograft materials can also be used. Each of the three mentioned grafts has specific features regarding morphological and structural properties, graft fixation and graft incorporation. Clinical studies have failed to identify any of the three grafts as superior to the others. When choosing the graft for surgery the different anatomy and function of the anterior and posterior cruciate ligaments have to be considered. For the treatment of multiple ligament injuries and for revision cases, thorough preoperative planning is necessary and modified graft selection may be required.