BTB Graft Research Articles

Short-term clinical results of revision anterior cruciate ligament reconstruction – double-bundle hamstrings graft vs. rectangular bone-patellar tendon-bone graft

Objective The purpose of this study was to compare short-term clinical result of revision ACL reconstruction (ACLR) using double-bundle hamstrings grafts (DB-HT) with that of ACLR using rectangular BTB graft (RT-BTB). Materials and methods Thirty-one patients (11 males and 20 females, mean age 21.7 years) were included in this study. Sixteen patients (primary graft: HT in 9, BTB in 7 patients) underwent revision ACLR with double-bundle technique using HT graft (DB-HT group), 15 patients (primary graft: ITB in 1, HT in 14 patients) underwent revision with rectangular tunnel using BTB grafts (RT-BTB group). All patients were evaluated for knee stability, muscle strength recovery of the knee, the Tegner activity score and the Knee injury and Osteoarthritis Outcome Score (KOOS) with a mean follow-up of 32.5 months (range, 24–61 months). Results One patient in DB-HT group had ipsilateral re-injury. One patient in the RT-BTB group had contralateral ACL injury. Side-to-side differences of anterior stability with KT-1000 were 0.8 ± 0.8 mm in DB-HT group and 0.8 ± 0.9 mm in RT-BTB group at final follow-up. Positive pivot shift rate in DB-HT group (35.7%) was higher than that in RT-BTB group (13.3%). There was no difference in muscle strength recovery, the Tegner activity score and KOOS subscores between the two groups. Multiple regression analysis revealed that femoral tunnel malposition and not graft selection was significantly associated with KOOS in revision surgery. Conclusions Positive rate of pivot shift in the DB-HT group was higher than in the RT-BTB group. However, graft choice in revision surgery did not affect subjective outcomes.

Short-term clinical results of revision anterior cruciate ligament reconstruction – double-bundle hamstrings graft vs. rectangular bone-patellar tendon-bone Graft

The purpose of this study was to compare short-term clinical result of revision ACL reconstruction (ACLR) using double-bundle hamstrings grafts (DB-HT) with that of ACLR using rectangular BTB graft (RT-BTB). Thirty-one patients (11 males and 20 females, mean age 21.7 years) were included in this study. Sixteen patients (primary graft: HT in 9, BTB in 7 patients) underwent revision ACLR with double-bundle technique using HT graft (DB-HT group), 15 patients (primary graft: ITB in 1, HT in 14 patients) underwent revision with rectangular tunnel using BTB grafts (RT-BTB group). All patients were evaluated for knee stability, muscle strength recovery of the knee, the Tegner activity score and the Knee injury and Osteoarthritis Outcome Score (KOOS) with a mean follow-up of 32.5 months (range, 24–61 months). One patient in DB-HT group had ipsilateral re-injury. One patient in the RT-BTB group had contralateral ACL injury. Side-to-side differences of anterior stability with KT-1000 were 0.8 ± 0.8 mm in DB-HT group and 0.8 ± 0.9 mm in RT-BTB group at final follow-up. Positive pivot shift rate in DB-HT group (35.7%) was higher than that in RT-BTB group (13.3%). There was no difference in muscle strength recovery, the Tegner activity score and KOOS subscores between the two groups. Multiple regression analysis revealed that femoral tunnel malposition and not graft selection was significantly associated with KOOS in revision surgery. Positive rate of pivot shift in the DB-HT group was higher than in the RT-BTB group. However, graft choice in revision surgery did not affect subjective outcomes.

Incidence and Characterization of Injury to the Infrapatellar Branch of the Saphenous Nerve after ACL Reconstruction: A Prospective Study

Objectives:The infrapatellar branch of the saphenous nerve is commonly injured in anterior cruciate ligament reconstruction (ACLR) causing sensory deficits around the knee. The primary purpose of this prospective study was to determine the incidence of patient reported sensory deficits around the knee following ACLR. The secondary purpose was to determine if sensory deficits caused by intraoperative injury present at 6 weeks changed in severity and total area after 6 months and 1 year postoperatively.Methods:Two-hundred and fifty patients that underwent ACLR with or without meniscal repair were prospectively enrolled. Variables for each patient included: type of graft, direction of tibial incision, number of portals, and length of surgical incision. The grafts used were categorized into three types: Allograft (allo), hamstring autograft (HS), or patella tendon autograft (BTB). At 6 weeks, patients completed a questionnaire to ascertain any sensory deficits over their knee. Patients rated their sensory deficit on a scale from 0-10 (“0” = (no deficit) to “10” (complete lack of sensation) and shaded areas on a picture of a knee split into nine rectangular segments (3 by 3 grid) to determine the location of any numbness. Patients completed the same questionnaire at 6 months and 1 year. Any patient that was noted to have no stated numbness at 6 weeks or 6 months was noted to have completed the study. A mixed effects linear regression model was used to identify variables which were predictors for the patient-reported severity of numbness.Results:Overall, 67/221 (30.3%) patients who underwent ACLR stated that they had no numbness at 6 weeks. Of those patients who reported numbness at 6 weeks, 16.6% (25/151) considered their numbness completely resolved by six months. At 1 year, 73.2% (90/123) reported their numbness had gotten better and 14.2% (18/123) considered their numbness resolved. The most common location of numbness was along the inferolateral aspect of the knee. The mean numbness rating for allografts was 2.73 +/- 0.32 (mean +/- standard error) at 6 weeks, decreasing to 1.04 +/- 0.26 at 6 months and 0.64 +/- 0.26 at 1 year for oblique and vertical incisions combined. A statistical model, controlling for time and incision direction, indicated that HS patients were 1.94 +/- 0.52 points higher than allograft patients across all time points, and BTB patients were 1.57 +/- 0.51 points higher than allo. However, there were no significant difference in mean numbness score between BTB and HS patients (p=0.521). Time had a negative impact on the patient reported severity of numbness score for all graft types. At 6 months this effect was -0.95 +/- 0.17 and at 1 year, -1.21 +/- 0.18. The use of BTB increased the mean numbness of affected segments by 0.67 +/- 0.23, while the use of a HS increased the mean numbness of segments by 0.39 +/- 0.21. The mean number of segments decreased slightly with time, down by 0.20 +/- 0.08 at 6 months (p=0.008) and 0.28+- 0.08 at 1 year (p=<0.001).Conclusion:Sensory deficits after ACLR follow the direction of the infrapatellar branch of the saphenous nerve. Patients who underwent ACLR with allo were less likely to develop sensory deficits compared to BTB or HS. Sensory deficits in allo patients were on average, less severe. Surprisingly, there was no significant difference in numbness between HS and BTB grafts. Surgeons should counsel their patients that sensory deficits are common postoperatively after ACLR, but that this sensory disturbance is likely to dissipate with time.

Quadriceps tendon autograft for ACL reconstruction: Evidence for increased utilization

ABSTRACT Purpose: To review the current literature of quadriceps tendon (QT) autograft tissue for ACL reconstruction and assess its evidence to become a more mainstream graft option Methods: A database review of clinical studies involving quadriceps tendon autograft tissue for ACL reconstruction was compared to results of ACL reconstructions using BTB and hamstring autograft tissue. Results: 20 articles were noted totaling 1,686 reconstructions including 6 studies which compared QT to either hamstring or BTB grafts. Quadriceps tendon grafts reported significantly less anterior knee pain (3.8%) compared to BTB (17.4%) and hamstring (11.5%) while providing clinical stability, adequate amount of graft tissue, and subjective outcomes comparable to traditional BTB and HS autograft options. Conclusions: Quadriceps tendon autograft is a strong and clinically proven alternative to BTB and hamstring autografts while decreasing graft site morbidity and should be considered a first line ACL graft option.

Central-Third Bone–Patellar Tendon–Bone Allografts Demonstrate Superior Biomechanical Failure Characteristics Compared With Hemi–Patellar Tendon Grafts

Background: Reconstruction of the anterior cruciate ligament (ACL) is commonly performed with a bone–patellar tendon–bone (BTB) allograft. However, grafts may result from harvesting the central region of a whole graft (C-BTB), the medial 10 mm of a lateral hemi-BTB (L-BTB) graft, or the lateral 10 mm of a medial hemi-BTB (M-BTB) graft. Purpose: To quantify potential differences in graft biomechanical properties when comparing whole versus hemi-BTB grafts. Study Design: Controlled laboratory study. Methods: Ten pairs of human BTB allografts (irradiated with 1.0-1.2 Mrad) were randomized to preparation as whole grafts or hemigrafts. From these, 10-mm grafts were prepared from the center or the most central portion, respectively. After measurements of tendon thickness, width, and length, specimens underwent cyclic tensile testing, followed by load-to-failure analysis. Biomechanical outcomes included cyclic elongation and creep strain along with the following failure characteristics: maximum load, elongation at maximum load, maximum stress, strain at maximum stress, and linear stiffness. Results: Regionally, the mean thickness of the C-BTB (5.18 ± 0.75 mm), M-BTB (5.08 ± 0.56 mm), and L-BTB (5.32 ± 0.62 mm) grafts were comparable (P > .72). Similarly, the mean length of the C-BTB (47.4 ± 6.73 mm), M-BTB (47.0 ± 5.45 mm), and L-BTB (50.7 ± 6.42 mm) grafts were alike (P > .43). While differences in cyclic elongation and strain were not significant, the M-BTB graft tended to elongate more (0.204 ± 0.13 mm; P = .075) and experience greater strain (0.56% ± 0.32%; P = .054) compared with the C-BTB graft (0.09 ± 0.03 mm and 0.23% ± 0.07%, respectively). Load-to-failure testing demonstrated a higher maximum load (2293 ± 531 N) and stiffness (356 ± 46 N/mm) of the C-BTB graft as compared with the M-BTB graft (1575 ± 325 N [P < .007] and 275 ± 37 N/mm [P < .008], respectively) and L-BTB graft (1585 ± 452 N [P < .008] and 277 ± 65 N/mm [P < .009], respectively). No differences were noted with respect to elongation or stress at maximum load among the grafts. Maximum stress in the C-BTB graft (45.4 ± 11.5 MPa) was greater than in the L-BTB graft (29.7 ± 10.6 MPa) (P < .03) and tended to be greater than the M-BTB graft (34.1 ± 6.27 MPa) (P = .087). Conclusion: Biomechanical failure properties (maximum load, stress, and stiffness) of the central portion of a whole BTB graft are superior to those of the medial portion of a lateral hemi-BTB graft and the lateral portion of a medial hemi-BTB graft. However, cyclic loading characteristics did not differ between grafts. Clinical Relevance: Although the true central-third BTB graft is biomechanically superior to hemi-BTB grafts, future studies are necessary to determine if the use of hemigrafts leads to an increased incidence of clinical failure.

The Biomechanical Effects of 1.0 to 1.2 Mrad of Gamma Irradiation on Human Bone–Patellar Tendon–Bone Allografts

Background: Recent data suggest that anterior cruciate ligament (ACL) reconstruction with irradiated allograft tissue may lead to increased failure rates. Hypothesis: Low-dose (1.0-1.2 Mrad) gamma irradiation does not significantly alter the preimplantation biomechanical properties of bone–patellar tendon–bone (BTB) allografts. Study Design: Controlled laboratory study. Methods: Cyclic and failure mechanical properties were evaluated for 20 paired central-third human BTB allografts, with and without 1.0 to 1.2 Mrad of gamma irradiation. Testing included cyclic loading at 0.5 Hz for 100 cycles from 50 to 200 N and failure testing at a strain rate of 10% per second. Results: Cyclic elongation did not change significantly (P = .151) with irradiation, increasing from a mean ± SD of 9.4 ± 2.1 mm to 11.3 ± 3.4 mm. Cyclic creep strain approached a significant increase with irradiation (1.3% ± 0.8% to 2.6% ± 1.5%; P = .076). Failure testing was not affected with irradiation with regard to maximum load (1680 ± 417 mm to 1494 ± 435 mm), maximum stress (40.8 ± 10.6 MPa to 37.5 ± 15.7 MPa), elongation (7.85 ± 1.35 mm to 8.67 ± 2.05 mm), or strain at maximum stress (0.158 ± 0.03 to 0.175 ± 0.03). Graft stiffness significantly decreased by 20% with irradiation (278 ± 67 N/mm to 221 ± 50 N/mm; P = .035). Conclusion: Low-dose (1.0-1.2 Mrad) gamma irradiation decreases BTB graft stiffness by 20%, but it does not affect other failure or cyclic parameters. Clinical Relevance: Aside from graft stiffness during load to failure testing, low-dose (1.0-1.2 Mrad) gamma irradiation of central-third human BTB allografts is not deleterious to preimplantation biomechanical properties.

Fremdmaterialfreie vordere Kreuzbandplastik mit der Patellasehne in Press-fit-Doppelbündeltechnik

Anterior cruciate ligament (ACL) reconstruction using autologous tendons (BTB patellar tendon, hamstrings, quadriceps tendon) in an implant-free fixation technique is becoming more and more popular due to biological and economical reasons. In 1987 an implant-free press-fit fixation technique of a BTB graft from the medial side of the patellar tendon (via mini-arthrotomy) was introduced and first published during the 4th ESKA Conference 1990 in Stockholm. Special emphasis is given to the anatomical orientation of the BTB graft. During the inside-out femoral press-fit fixation the bone-ligament margin of the graft is placed directly into the femoral insertion line of the natural ACL adapting its double-bundle structure. The graft is fixed by press-fit within the tibial metaphysis and its ligamentous part is secured in the metaphysis by harvested cancellous bone blocks driven into the joint line from the outside. The postoperative regime includes weight-bearing as tolerated and free motion. Out of 159 patients 95 could be seen for follow-up after an average of 10.7 years. The final IKDC knee score revealed 22.1% in group A (very good) and 62.1% in group B (good). The Tegner activity level was 6.8 preinjury and 6.0 postoperatively. The average KT 1,000 side-to-side difference was 1.8 mm. Subjectively no patient complained of instability and 99% of the patients could kneel on hard ground with minimal or no complaints. ACL revision surgery due to graft failure was not necessary in any of the patients. Advantages of the described procedure are a narrow anatomical orientation including the double bundle structure of the ACL, rapid graft incorporation by bone-to-bone healing, lack of bone resorption at the graft-host interface, decreased donor site morbidity, cost-effectiveness and ease of possible revision surgery.

New technique for knee flexion contracture with patella infera using patellar tendon reconstruction combined with anterior capsular shift: a case report

A 24-year-old male presented with an open fracture of the left patella (Gustilo-Anderson grade III-A) and fracture of the left femoral lateral condyle, and subsequent patella alta suggesting rupture of the left patellar tendon. This initial injury was treated 6 months earlier in another hospital. He was referred because of limited knee motion and radiographs showed severe patella infera. By means of a combination of a contralateral BTB graft and soft tissue repair named anterior capsular shift, the knee contracture with patella infera was resolved successfully.

Functional outcomes and health-related quality of life after robot-assisted anterior cruciate ligament reconstruction with patellar tendon grafts

During a short period of time, surgical robots had been propagated for automated tunnel placement in anterior cruciate ligament (ACL) reconstruction. Clinical outcome data are currently unavailable. Between 2000 and 2003, 152 patients underwent ACL replacement with the assistance of the Computer Assisted Surgical Planning and Robotics system (CASPAR, OrtoMaquet, Germany) at our hospital. After minimal invasive pin placement in both the tibia and femur, computed tomography was used to register anatomical landmarks and to plan graft tunnel alignment. The robot was used to drill tibial and femoral tunnels in an outside-in fashion according to pre-operative planning. There was one procedure-specific Serious Adverse Event (i.e., an intraoperative transection of the posterior cruciate ligament). After IRB approval, all patients were invited for a follow-up examination. Data from 100 patients (35 women, 65 men, mean age 35 [SD 11] years, median follow-up 61 [range 42-77] months) form the basis of this report. Side-to-side differences in anterior laxity were measured with the KT-1000 arthrometer. Patient-centered outcomes included the Lysholm-Score, the lower extremity functional scale (LEFS), and the Short Form 36 (SF36). The mean KT-1000 side-to-side difference was 0.89 [95% confidence interval (CI) 0.52-1.26] mm. Eight and five patients had a positive Lachman and pivot shift test, respectively. The Lysholm-Score averaged 86 (95% CI 83-89) points. Excellent, good, fair, and poor outcomes were reported by 38, 32, 20, and 10 patients. The LEFS averaged 85 (95% CI 82-88) points. The mean SF36 Physical Component Score was 48.4 (95% CI 46.5-50.3), indicating residual deficits compared to the population norm. All tibial graft tunnels did not cross the Blumensaat line, but were placed slightly anterior to the optimal center of 42% reported in previous studies. Compared to literature data, robot-assisted ACL reconstruction with BTB grafts may lead to higher knee stability, but poorer functional outcomes. The immense additional efforts with the procedure did not pay off in a benefit to patients.

Minimally invasive selective bundle anterior cruciate ligament reconstruction

Aim: There has been a renewed interest in the concept of partial ACL tear, of either the anteromedial or posterolateral bundle. We hypothesise that the nature of the mechanism of injury may predict the type of tear encountered at surgery, and that the clinical stability examination will vary according to the pattern of ACL bundle tearing. The type of ACL reconstruction will therefore vary according to the operative findings. Method: Between May and October 2007, a total of 100 consecutive patients for primary ACL reconstructions using hamstring tendon or BTB grafts by the senior author (HM) were recruited for the study.

Mechanical properties of radiation-sterilised human Bone-Tendon-Bone grafts preserved by different methods

Patellar tendon auto- and allo-grafts are commonly used in orthopedic surgery for reconstruction of the anterior cruciate ligaments (ACL). Autografts are mainly used for primary reconstruction, while allografts are useful for revision surgery. To avoid the risk of infectious disease transmission allografts should be radiation-sterilised. As radiation-sterilisation supposedly decreases the mechanical strength of tendon it is important to establish methods of allograft preservation and sterilisation assuring the best quality of grafts and their safety at the same time. Therefore, the purpose of this study was to compare the tensile strength of human patellar tendon (cut out as for ACL reconstruction), preserved by various methods (deep fresh freezing, glycerolisation, lyophilisation) and subsequently radiation-sterilised with doses of 0, 25, 50 or 100 kGy. Bone-Tendon-Bone grafts (BTB) were prepared from cadaveric human patella tendons with both patellar and tibial attachments. BTB grafts were preserved by deep freezing, glycerolisation or lyophilisation and were subsequently radiation-sterilised with doses of 0 (control), 25, 50 or 100 kGy. All samples were subjected to mechanical failure tensile tests with the use of Instron system in order to estimate their mechanical properties. All lyophilised grafts were rehydrated before performing of those tests. Obtained mechanical tests results of examined grafts suggest that deep-frozen irradiated grafts retain their initial mechanical properties to an extent which does not exclude their clinical application.

Einpresskraft bei Press-fit Fixierung der vorderen Kreuzbandplastik - eine Grundlagenstudie

The aim of this study was the determination of the axial fixation load resting on smooth press-fit dowels needed for fixation of the patellar tendon graft (BTB) in order to reach the same fixation properties compared to the interference screw on anterior cruciate ligament (ACL) plasty. Bovine test specimens with 27 BTB grafts fixed in tibial drill holes were used and divided in 3 groups: interference screw, and press-fit cylinder (Ø 7 mm) with 150 N and 100 N axial loads. Prior to fixation, impactation of the transplant into bone was carried out. Failure testing was done in a tensiometer at a cross-head speed of 50 mm/min. Determinations of peak load and stiffness were also made. Similar peak loads and stiffness were reached on introducing a press-fit dowel (slashed circle 7 mm) with 100 N and 150 N axial load compared to interference screw fixation of the BTB graft. Peak load: 988.1 N +/- 365.1 (screw) versus 1 210.4 N +/- 292.4 (dowel 150 N) and 1 109.8 N +/- 505.4 (dowel 100 N). Stiffness: 86.4 N/mm +/- 20.5 (screw) versus 102.4 N/mm +/- 15.2 (dowel 150 N) and 77.1 N/mm +/- 11.0 (dowel 100 N). There was no significant difference. When introducing a press-fit dowel (slashed circle 7 mm) with 100 N axial load into a preformed bone bed, the same fixation properties are reached as in the case of an interference screw on BTB-ACL plasty.

ACL reconstruction with BTB graft: Unusual evolution of knee arthrofibrosis case report

Knee arthrofibrosis, which usually occurs after trauma or surgery, can inhibit joint biomechanics. An elaborated interaction of growth factors and other inflammatory mediators initiates and coordinates this deleterious tissue proliferation. Knowledge of risk factors can aid clinicians in helping patients avoid knee arthrofibrosis. Once the condition is present, a history and examination are imperative to institute the most appropriate treatment regimen. Nonoperative measures can be used as therapy, though surgery is often necessary for optimal results. We have analyzed problems in patient with uncommon evolution of knee arthrofibrosis following ACL recontruction with BTB autograft.

Injuries of the anterior cruciate ligament: What is state of the art?

BACKGROUND: The anterior cruciate ligament (ACL) is the most commonly injured ligament in the knee. However, there is an ongoing debate of when and how to fix an ACL rupture. METHODS: This article reviews common treatment methods of ACL ruptures. RESULTS: Reinsertion of the ACL does not appear to result in proper ligament healing. There are two methods to reconstruct the ACL: patellar tendon grafts (BTB) and semitendinosus-gracilis grafts (STG). CONCLUSIONS: Ruptures of the ACL should be treated in active people as they require a stable knee. STG grafts seem to have an advantage compared with BTB grafts as far as postoperative pain and complications are concerned. However, competitive athletes will require a BTB, as this graft allows an earlier comeback compared with the STG graft.

Recovery of extensor muscle strength in athletes after anterior cruciate ligament reconstruction

We investigated the effects of the use of different autograft materials on the early postoperative recovery of extensor muscle strength after anterior cruciate ligament (ACL) reconstruction. Reconstruction was performed in 172 athletes with ACL-deficient knees; in 32, a quadriceps tendon-patellar tendon substitute (QTS) was used; in 79, semitendinosus and gracilis tendons (STG) were used; and in 61, a bone-patellar tendon-bone graft (BTB) was used. For QTS and STG autografts, a ligament augmentation device was used. Each group received the same accelerated rehabilitation program. Muscle strength was measured periodically 3–18months after the operation, using a Cybex II dynamometer (Cybex Division of Lumex, Ronkonkoma, NY, USA). Knee extensor strength was evaluated, using the side-to-side ratio and the body weight ratio, to give a precise assessment of permissible sporting activity. After a period of 1year, the percentage of athletes who recovered their extensor muscle strength at a level more than 80% of that in the uninvolved knee was 15.6% for those with QTS grafts, 41.0% for those with BTB grafts, and 77.9% for those with STG grafts (P < 0.001 between QTS and STG, P < 0.05 between QTS and BTB, and P < 0.001 between BTB and STG). The body weight ratio in men showed that, after reconstruction, recovery of extensor muscle strength sufficient for participation in vigorous sport required 6months for STG grafts, 12months for BTB grafts, and 18months for QTS grafts.

The Effects on Knee Joint Function after ACL Reconstruction Using Patellar BTB Graft

The Effects on Knee Joint Function after ACL Reconstruction Using Patellar BTB Graft