Kneeling Assessment After Anterior Cruciate Ligament Reconstruction Using Bone-Patellar Tendon-Bone Autograft Versus Hamstring Autograft

Background: ACL reconstruction surgeries is a common surgery that aim to provide stability and return functionality post ACL injury. Commonly, bone patellar tendon-bone (BPTB) and hamstring tendon autografts are used for the reconstruction. The choice of optimal autograft remains debatable to achieve satisfactory outcomes for various activities after reconstruction, including kneeling as widely needed, especially in prayers among Muslims. Kneeling with considerable ranges of motion and the minimum level of pain is still under rigorous investigations to choose proper autograft. Purpose: Hereby, we compare kneeling outcomes post-operatively using bone-patellar tendon-bone autografts with hamstring autografts for ACL reconstruction. Methods: A retrospective cohort study; Level of evidence (III) has enrolled. Adult patients underwent primary ACL reconstruction using either BPTB or HS autografts after they consented at a single institution with a minimum of 1-year as follow-up post-operatively were reviewed for assessment of the surgery’s outcomes in regards of kneeling pain and subjective assessment measures using International Knee Documentation Committee (IKDC) evaluation system. Results: A total of Thirty-two males were met our inclusion criteria. Analysis of data provided that 12 patients were in the BPTB group and 20 patients in the HS group. All patients show ACL rupture was sustained during participation in the athletic activity. After a follow-up of 1-year, there was no statistically significant difference between scores of two groups when comparing patient-reported outcome measures, with mean IKDC scores of 68.5 and 62.55 in the BPTB and HS groups, respectively. Interestingly, insignificant statistical differences observed in both groups regarding kneeling pain in the BPTB group when compared with the HS group. Conclusion: The findings of our study have shown that Arthroscopic ACL reconstruction using either hamstring autograft or bone patellar tendon autograft ends with equally reasonable satisfactory outcomes, with an insignificant difference in kneeling pain between both groups.


Background
An anterior cruciate ligament (ACL) is a common knee ligamentous injury that causing instability with an incidence of 0.38 per 1000 each year in the united states [1]. The ACL reconstruction surgeries aim to provide stability and return functionality and expected to prevent injuries of the meniscus or leading to degenerative changes such as osteoarthritis [ 2].
It is a common practice that bone patellar tendon-bone (BPTB) and hamstring tendon autografts are used for the reconstruction. Bone patellar tendon-bone (BPTB) autograft was first described by Jones in 1960, which became popular by Erickson until the late 1970s [ 3]. However, this methodology of reconstruction was associated with various post-operative issues such as harvesting site morbidity and stiffness. A systematic review conducted from the USA by Monaghan et al. has shown an increase in long-term anterior knee pain, kneeling pain, and higher rates of osteoarthritis were noted with BPTB graft use [ 4]. This motivated surgeons to look for alternatives with reasonable outcomes for their patients as at the beginning of the 1990s [3], a new methodology was introduced to reconstruct the anterior cruciate ligament through two hamstring tendons (HT): gracilis and semitendinosus.
The choice of optimal autograft either BPTB or HS autograft remains controversial to achieve satisfactory outcomes for various activities with a considerable range of motion and minimal anterior knee pain after the reconstruction [ 5]. It is attributed to the advantages and disadvantages each autograft has and the absence of clear evidence-based guidelines that recommend one autograft in favor of the other [6]. Ideally, the graft used for ACL reconstruction should reproduce the anatomic and biomechanical properties of the native ligament, and using each autograft is debatable as each one has its characteristics. Nevertheless, a long-term prospective study that compared patellar tendon versus semitendinosus tendon autografts for anterior cruciate ligament reconstruction shows no significant differences between the groups in donor-site morbidity [ 7]. However, most of the surgeons in our area avoid BPTB graft of ACL reconstruction as they claimed that it could cause anterior knee pain and difficulty in kneeling, especially in Muslims who need hyperflexion during praying multiple times a day [ 8].
Therefore, our study aimed to measure the functional outcomes and kneeling ability of patients whose underwent ACL reconstruction by BPTB autograft among Saudi Arabian patients and compare the results with hamstring autograft. The primary endpoint of this project was to aid the surgeon in making a correct decision with their patients with minimal post-operative anterior knee pain experienced by patients. A secondary objective was to describe the severity of the pain during a range of daily activities, but particularly during kneeling, which is essential knee activity among Muslim people to perform prayers.

Materials And Methods
Our Retrospective cohort study enrolled adult patients whose underwent ACL reconstruction with autologous bone-patellar tendon graft (BPTB) and hamstring autograft that met inclusion criteria. Pediatric age group younger than 18 years old or patients with any associated ligamentous injuries that require surgery, previous meniscectomy, or meniscal injury requiring more than one-third meniscectomy at the time of reconstruction were excluded.
Graft choice between BPTB and HS autograft was decided after a thorough discussion of the risks and benefits of each one between the patient and the surgeon. Surgeries conducted at a single tertiary hospital in Saudi Arabia by three fellowship-trained sports surgeons. A standard rehabilitation protocol was prescribed to all patients by the physiotherapy department after the surgery, regardless of the ACL graft that they received.
At mean follow-up duration with a minimum 1-year post-reconstruction, patients who were willing to participate interviewed and inquired with using the International Knee Documentation Committee evaluation (IKDC 2000) score to measure the functional outcomes of the operated knee. The demographic data collected, including patients' age, sex, BMI affected knee, type of graft used, and duration since the injury until surgery has been performed. Thus, Kneeling pain was assessed by asking the patient to kneel on a carpeted surface for approximately 1 minute and to note the presence of pain. Intensity of pain was graded from 0 to 10, with 0 being no pain and 10 being extremely severe. Pain scales were categorized as following: mild pain (0-3 points); moderate pain (4-7 points); and severe pain (8-10 points) [9]. To achieve our study's purpose, moderate and severe are the categories that indicate the existence of anterior knee pain. Furthermore, anterior drawer tests were performed before and after the surgery to evaluate the knee stability.
The data was analyzed using SPSS 23 version (Statistical Package for the Social Sciences; Chicago, IL). Descriptive statistics were conducted for the patient's demographic and categorical data. Comparisons of frequency counts for categorical data were made with the chi-square test. Likewise, for data of continuous variables, the paired samples t-test was used. A p value of < 0.05 considered a significant Statistically.
Informed consent was taken from all participants after a thorough explanation of the study's rationale. Institutional review board (IRB) approval obtained before the commencement of our study.

Patient Characteristics
A total of thirty-two males were included in our study, with 12 patients were in the BPTB group, and 20 patients in the HS group. There were no statistical differences between the groups regarding age as the majority presented in the late 20 s and body mass index of being morbidly obese in both groups (Table 1).
However, there was a significant difference in duration of injury until the surgery has been performed between the two groups i.e., in HS group patients extend to be for almost two years in comparison to BPTB of less than one year, respectively. In all patients of our study, the ACL rupture sustained during participation of the athletic activity regardless of sport type. 60.8% of the patients were affected of the left knee.

Clinical Evaluation
Patients who were available after a follow-up of 1 year without sustained complications of instability or rerupture have undergone a clinical assessment with anterior drawer test and compared with the findings that exist before the surgery. Two patients in the HS group were positive after 16 months postoperatively. Lachman's test findings were not documented for all patients ( Table 2).

Patient-Reported Outcomes measure
We found no significant difference between groups when comparing patient-reported outcome measures, with mean IKDC scores of 68.5 and 62.55 in the BPTB and HS groups, respectively (Table 3). Interestingly, the insignificant statistical difference observed in both groups in regard to kneeling pain in the BPTB group when compared with the HS group. According to IKDC item 9c, ten patients in the BPTB group versus 18 in the HS group experienced mild pain during kneeling (p = 0.862).

Discussion
Choosing the optimal graft for ACL reconstruction is remaining a controversial topic, attributed to the various factors that confound to obtain the proper decision such as patient's age, sports activities, surgeon preference, and nature of the occupation. The most common used autografts that surgeons preferred to use for their patients are hamstring tendon (HS) or bone-patellar tendon-bone (BPTB) autografts reconstruct the ACL A meta-analysis of 22 studies with a total of 1930 patients undergoing ACL reconstruction conducted by Xie et al., reported that patients treated with BPTB autograft had more significant long-term kneeling pain and anterior knee pain when compared with those treated with HS autografts [ 17]. Furthermore, Li et al. evaluated outcomes of ACL reconstruction among nine randomized controlled trials for 738 patients and found that BPTB autografts produced significant anterior knee and kneeling pain. ] 18[ Therefore, we aimed in our study to investigate the long-term outcomes of BPTB autograft versus HS autograft for which producing a better impact on patient's activities. Interestingly, our study conducted among sample of muslim patients whom need kneeling as a major activity to perform prayers which should assist the surgeon to select the proper autograft of superior outcomes for the injuried patients. which might contribute to assist the surgeon in selecting the autograft with superior outcomes in the region. Hereby, the purpose of our study was obtained by the international knee documentation committee (IKDC) subjective knee evaluation form, which is one of the reliable instruments used commonly to determine results following various knee procedures, including ACL reconstructions. Thus, it is valid to measure knee symptoms as well. [ 19] This measurement tool was used as a primary method for the collected sample to measure subjective satisfaction and kneeling pain postoperatively. We found interestingly in our result that insignificant differences between groups when comparing patient-reported outcome measures, with mean IKDC scores of 68.5 and 62.55 in the BPTB and HS groups, respectively. According to IKDC item 9c, ten patients in the BPTB group versus 18 in the HS group experienced mild pain during kneeling, which is reasonable. Overall postoperative results are satisfactory within each group in terms of IKDC subjective scores, activities of daily living when compared to pre-operative scores. Similar findings reported by Eriksson et al. which were consistent with majority of patients in the group 80% scored normal and minimal pain while 20% of patients scored abnormal IKDC grades [ 20]. Outcomes of our study demonstrates that both types of reconstruction are effective methods of restoring knee stability and producing satisfactory outcomes in means of post-operative anterior knee pain and kneel pain. There was insignificant statistical difference in the IKDC score between two groups after 1-year of follow-up [ 21].
To minimize the bias of our results, we reviewed magnetic resonance imaging (MRI) findings of contributed patients for this study who scored severe kneeling pain to investigate whether any confounding risk factors participated. Two patients had BPTB autograft with a result of 7, 10 scores of kneeling pain, respectively. It consisted of complete ACL tear associated with features of posterior lateral corner syndrome and complicated Baker's cyst preoperatively in their MRI report. Additionally, one patient autografted with hamstring scored 10 (the maximum intensity) had high-grade anterior cruciate ligament tear associated with Posterior horn of medial meniscus oblique tear. No distinguished findings existed among patients who scored mild-moderate pain. Therefore, there is a correlation between the severity and the MRI abnormality findings.
A recent short-term study by Laxdal et al. showed that insignificant clinical differences could be found between two groups as well [22]. Similar findings published a long time in 1994 by Corry et al. found that the two grafts did not differ in terms of clinical stability, range of motion, and general symptoms, which consistent with our study findings [ 23]. Similarly, Biau et al. conducted a meta-analysis of various studies concluded that insignificant differences between two grafts but recommended HS for patients who need jumping [24]. However, this might be attributed to the newer surgical techniques that performed, which leads to an insignificant difference in terms of complications. This perspective of the new surgical techniques should be taken into consideration and investigate extensively as BPTB is still a considerable option that would be advised for patients of certain ethnic origins and religions such as Muslims who need to kneel for prayer [ 25].
In addition, the potential muscle weakness following hamstring autograft for ACL reconstruction is concerned and investigated in many studies. Current literature results that surgeons need to balance adequate graft size and strength with the potential for donor-site morbidity when performing an ACL reconstruction with hamstring autografts. However, this aspect remains not conclusive yet as a hamstring function analysis by certain types of sports would be required to elucidate this issue, and it does not a concern aspect currently in our study [ 26[. Chee et al. conducted a meta-analysis recently that comparing the outcomes of BPTB grafts versus 4-strand hamstring autografts. They reported a significant negative effect in the aspects of anterior knee pain, kneeling pain, and extension deficit that did not support the use of BPTB grafts with favored the hamstring autograft rather than the BPTB graft for anterior knee pain and kneeling pain. Thus, it concluded that the 4-strand hamstring ACL reconstruction has comparable clinical results with the BPTB graft but with fewer postoperative complications [ 27[. However, other studies have found that an ACL reconstruction with a BPTB graft might be superior in aspects of stability and preferred to be used for the young athletic patient ] 17, 28[. Therefore, both autografts are providing satisfactory outcomes in long-term means.
It is evident that ACL reconstruction surgeries performed by trained sport orthopedic surgeons have better outcomes than surgeries performed by general orthopods. In our study, there were three fellowship-trained sports orthopedic surgeons operated on all patients, which considered as a strength, but various surgical techniques performed, which might contribute to results bias. Although we enrolled a consecutive series of patients in our study to reduce the margin of selection bias, these patients were not randomized, which have been subject to selection bias. Thus, all patients involved were males and young with ACL rupture was sustained during participation in the athletic activity regardless the type of sport. At a 10-year follow-up, there were no gender differences regarding outcomes of failures, radiographic osteoarthritis, or overall IKDC scores [31]. Additionally, our study has been performed on a retrospective review basis, and as such, it carries inherent shortcomings. Finally, the sample size of patients is considered minimal compare to the original patients that have been operated due to loss of follow-up and strict inclusion & exclusion criteria we had, which potentially introduced bias to our results and reduce power for statistical significance and increase margin errors of data analysis.

Conclusion
Findings of our study have shown that Arthroscopic ACL reconstruction using either hamstring autograft or bone patellar tendon autograft ended with equally reasonable satisfactory outcomes regarding return to functionality and activities of daily living with an insignificant difference in kneeling pain between both groups. However, further long-term prospective randomized clinical trial studies are warranted.

Ethics approval and consent to participate:
All procedures performed in the study were under the ethical standards of the institution at which the studies were conducted, and the ethical approval obtained. Informed consent was obtained from all individual participants included in the study.

Availability of data and materials:
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Conflict of interests:
There is no conflict of interest

Funding:
The authors declare that they have no funding for this research

Authors' contributions:
We thank Khalid alhumam, Mohammad Alarbash, Haya AlMousa, and Hissah AlTurki for helping us in interviewing patients and collecting data. Also, I would like to thank all patients who cooperate with us in this research.