Clinical outcome of trans-portal anatomic anterior cruciate ligament reconstruction with quadrupled semitendinosus graft

and


INTRODUCTION
Anterior cruciate ligament (ACL) tears are common but devastating injury of knee joint in athletic population.][3] The risk of secondary meniscus tear(hazard ratio 18.0), osteoarthritis(OA, hazard ratio 14.2) and the need for total knee arthroplasty (hazard ratio 5.0) are significantly higher in ACL deficient knee without anterior cruciate ligament reconstruction (ACLR) than those without ACL tear. 4 Although there are many auto and allograft options, the graft choice in ACL reconstruction is still matter of surgeon's preference.The most commonly used grafts in ACL reconstruction are quadriceps tendon, bone patellar tendon bone (BPTB) and semitendinosus/Gracilis (ST/G) tendons. 5t of several available graft choices, the bone-patellar-tendon bone (BPTB) is still most commonly used graft in ACLR. 6However, there are several disadvantages of BPTB graft like anterior knee pain, quadriceps weakness, extension deficit of knee and patellar bone fracture. 7To avoid these postoperative donor site complications of BPTB, there has been increased use of hamstring tendon (HT) autograft.However, there are several concern about use of HT graft : failure to achieve immediate rigid fixation to bone, lower stiffness compared to native ACL or BPTB graft, tunnel widening, risk of increased laxity in long term, reduced strength of hamstring in deep flexion and difficulty in controlling internal rotation of tibia. 8Comparing to combined semitendinosus/Gracilis(ST/G), the quadrupled semitendinosus graft is larger in diameter and provides a stronger graft. 9urthermore, it also saves Gracilis tendon which is important flexor of knee and also helps to control internal rotation of knee.Therefore, we studied short-term evaluation of single bundle ACL reconstruction using quadrupled semitendinosus graft in our clinical setup.We hypothesized that quadrupled semitendinosus tendon graft provides comparable functional outcome as other grafts in ACL reconstruction do.

METHODOLOGY
This was a prospective case study conducted between February 2021 to July 2022, in department of orthopedics of Nobel medical college, after getting ethical clearance from IRC (Reference No. 25/021).An informed consent was taken from all patients before enrolment in this study.All patients having primary ACL tear presented to our department aged between 18 to 50 years were included in this study.Patients having multi-ligamentous knee injury requiring additional surgery for other ligaments, previous knee injuries and deformities and those patients having less than 28cm length of harvested semitendinosus (ST) graft were excluded.Patient's medical histories, mechanism of injury, demographics, post operative complications and concomitant knee pathologies, if any were recorded.Clinical examination was performed for signs of instability via Lachman and anterior drawer tests in outpatient department (OPD) and by pivot-shift test under anesthesia at the beginning of the surgery. 2 Findings were graded.The magnetic resonance imaging was done for each patient to confirm diagnosis of ACL rupture and to see any other associated knee pathologies preoperatively.

Surgical technique
Anterolateral and slightly more medial anteromedial portals were used for single bundle reconstruction of ACL.A diagnostic knee arthroscopy was done to examine ACL tears and injury to other structures of knee.Semitendinosus graft was harvested through a longitudinal incision of 3cm to 4cm at 2cm medial to tibial tuberosity.To dissect pes anserinus a reverse L-shaped incision was given at sartorius fascia and flaps were reflected.The semitendinosus was isolated and harvested using open tendon stripper.To maximize the length of the graft, we included periosteum from the tendon insertion site, which added extra 1 to 2cm in length of graft.The ST graft were prepared and quadrupled and length and diameter were measured.The torn ACL was debrided leaving tibial foot print as much as possible.Associated meniscus tear or chondral injuries were treated first.The guide wire was inserted in in femoral attachment site using femoral offset guide.The guide wire was over-drilled with a 4.5mm Endobutton drill through femur to emerge on lateral cortex of femur.The final closed femoral socket of 18 to 20mm was created by cannulated drill equal to diameter of prepared graft.An ACL guide was used to create tibial tunnel at an angle of 50 degree.The ACL guide was positioned slightly medial to center of ACL stump.The guide pin was placed above the pes anserinus and anterior to MCL.The open tibial tunnel was created as same diameter as prepared graft.The graft was passed and femoral side was fixed with variable loop Endobutton (Figure .1 a-g).The tibial fixation was done with bioabsorbable interference screw only when quadrupled graft length was ≥7.5cm.In those patients where quadrupled graft length was between 7 to 7.5cm and where we had any doubt regarding stability of tibial fixation of graft, additional cortical screw and washer were used for tibial fixation.The post-operative X-ray was done in every patient (Figure .2).
Range of motion of the knee, isometric muscle exercise and closed kinetic chain exercises were started the day after operation and gradually progressed based on accelerated rehabilitation program.Patients were permitted to bear weight with knee immobilizer as tolerated immediately after ACL reconstruction.Walking without support and brace and range of motion more than 90 degree were allowed at around 4weeks.Indoor swimming and cycling allowed after 4weeks.Open kinetic leg curl exercise started after 8weeks.Running allowed after 12weeks and sports activities and heavy works allowed after 9months.
The final clinical examinations like Lachman, anterior drawer and pivot shift tests were done at 12months and findings were recorded.For overall evaluation, subjective knee scoring systems like Lysholm score and Tegner activity scale were used. 10urthermore subjective evaluation was assessed by numeric rating scale (NRS) from 0 (very unsatisfied to 10 (very satisfied).sampling method, a non-probability sampling method, was applied in this study.All of the patients, presenting during the study period, with primary ACL tears were assessed for eligibility and the patients meeting the inclusion criteria of the study were all included in this study after receiving their consent.In the study period from February 2021 to July 2022, a total of 33 patients met the inclusion criteria and thus the sample size of this study was 33.

RESULTS
A total of 35 patients underwent ACLR with quadrupled semitendinosus hamstring graft during our study period.Two patients lost follow up and hence excluded from study.There were 27 male and 6 female patients.The mean age was 27.5±8.2years ranging between 16 to 49 years.The right knee was involved in 18 patients and left in 15 patients.The commonest mode of injury was RTA in 14 patients (43%) followed by sporting activities in 13 patients (39%) and fall from height in 6 patients (18%).The mean duration from injury to surgery was 7.2± 5months (Range from 3 to 24months).The average diameter of graft was 8.03±0.35mm(Table.1).Out of 33 patients, six (18%) had MMT and 3(9%) had LMT.Two MMT and one LMT were repaired while remaining were debrided.The associated chondral injury was found in 5 patients.Thirty patients had full range of motion and three patients had terminal deficit of 5 to 10 degree at last follow up.Out of 33, only two patients had positive grade 1 pivot shift test after operation (Table .2).The mean Lysholm score was 92.3±5.1 (range 79-99) at followup.Twenty-four patients (70 %) were rated as very good (91-100 points), seven (23 %) as good (84-90 points) and two patients (7 %) as fair (65 to 83 points).None was assessed as poor.
Two patients had superficial wound infection which subsided with dressing and antibiotics.One had knee effusion at 6weeks and one had post operative stiffness which improved with analgesics and physiotherapy.

DISCUSSION
The goals of ACLR are to restore stability, full ROM and to prevent secondary injuries and knee arthrosis.The majority of patients in our study showed excellent results with stable knee and had returned to preinjury activity level.The lysholm score of majority of our patients were excellent or good with a mean value 92.3±5, similar to other studies by 11 Charlton et al, 12 William et al, 13 Gifstad et al, and many other studies who reported a lysholm score of about 90.The successful and fast return to preinjury level depends on rehabilitation protocol.There is no significant association between postoperative brace treatment with better outcome. 14e had similar conclusion in our study and postoperative rehabilitation was started as soon as possible.Our study reports 70% (23 patients) return to pre-injury activity level.Anderson et al and Sajovic reported 78% and 81% of return to pre-injury activity level respectively. 15,16whereas, in a study by Kropft et al. nineteen (82.6%) patients were able to perform sternous activity but only 10 (43.5%) of them were able to return to pre-injury activity levels in terms of frequency and type of activity. 17The literatures do not show consistent rate of return to sports. 18,19 this study, 6 (18%) patients had positive grade I Lachman test.
Gifstad and William reported 33% and 11% positive Lachman respectively in their studies. 13,12In our study 31 patients (94%) had negative pivot shift test which indicates very high rate of knee stability.It had been observed that two patients who had grade 1 pivot shift postoperatively showed lesser lysholm score and overall satisfaction.In a study by Omid Shahpari et al. 72 patients (87%) had negative pivot shift test. 20Kocher et al could not find any correlation between instrumented knee laxity and Lachman examination and any subjective variables of symptoms and function. 19But Pivot shift test had significant association with patient satisfaction whereas Peterson et al did not find any statistically significant correlation between pain, giving way, Lachman and pivot shift results or arthrometer.The pivot shift test may be better measure of functional instability than instrumented knee laxity or Lachman test after anterior cruciate ligament reconstruction. 21ree patients (9%) had terminal flexion deficit of 5 to 7 degree but no patients had extensor lag in our study.In study by Beynnon et al , they had flexion deficit of five degree or more in 17% of patients and extensor lag of 3 degree in 3% in their patients in hamstring autograft group. 22fstad et al reported re-rupture rate of 6%. 13 In another study by Sajovic et al .showed ACL revision rate of 7%. 16The overall rate of graft failure was 4.9% and in hamstring graft group it was 4.1% in Freedman et al study. 23We had no graft failure in any patients at 1 year follow up.It might be because of less follow up duration.
Even if we reconstructed the ACL with an ST graft alone, the patients obtained at least the same level in the clinical outcome scores compared to other studies using an STG graft. 24,25Similar findings were seen in review by Samuelsson et al. 26 They could not quote any differences between the selected graft and the self-reported data including the Lysholm score.

CONCLUSION
Anterior Cruciate Ligament Reconstruction using quadrupled semitendinosus graft only has good clinical outcomes and it also increases diameter of graft.It also helps to save Gracilis tendon which is important in deep flexion of knee.We recommend quadrupled ST graft for ACL reconstruction if length of graft is adequate.

LIMITATIONS OF THE STUDY
Although we have found excellent results comparable to other studies, there are several limitations.The sample size is less and there are drawbacks of non-probability sampling method.The other is that it is not comparative study with other graft.
A structured questionnaire, with sections for demographic details; clinical outcomes that included Lachman, anterior drawer, and pivot shift tests; subjective scoring scales like Lysholm score, Tegner activity scale, and numeric rating scale from 0 (very unsatisfied) to 10 (very satisfied) was used.Independent variables of this study were the demographic details and the result of the pre-operative pivot shift test.Dependent variables of this study were the result of post-operative Lachman, anterior drawer, and pivot shift tests; Lysholm score, Tegner activity scale, and numeric rating scale.Analytical strategy Descriptive statistics were used to present the independent and dependent variables.The normality of the data was checked through the Shapiro Wilk test.Categorical variables are presented in terms of proportion while appropriate measures of central tendency (mean/median) and dispersion (standard deviation/interquartile range) are used for continuous variables.The curated data were refined and imported to SPSS software version 20 for analysis.

Fig 2 :
Fig 2: a Tibial fixation with bioscrew.b.Tibial fixation reinforced with addition washer and screw.

Table 2 :
Results of post-operative clinical (objective) tests Lachman(grade I)Anterior drawer test(grade I) Pivot shift test(grade I)