|Year : 2021 | Volume
| Issue : 4 | Page : 316-321
Short-term comparison between resection and preservation of the infrapatellar pad of fat in patients undergoing primary total knee replacement
Wisam Khalid Fayyadh1, Las Hwaizi2, Laween Omer Musa3
1 Department of Surgery, College of Medicine, University of Duhok, Duhok, Iraq
2 Department of Surgery, Kurdistan Board of Medical Sciences (KBMS), Erbil, Iraq
3 College of Medicine, Duhok Center of Orthopedic Branch of Kurdistan Board of Medical Sciences, University of Duhok, Duhok, Kurdistan Region, Iraq
|Date of Submission||09-May-2021|
|Date of Acceptance||07-Jul-2021|
|Date of Web Publication||18-Dec-2021|
Wisam Khalid Fayyadh
Department of Surgery, College of Medicine, University of Duhok, Zakho way, Duhok, Kurdistan Region.
Source of Support: None, Conflict of Interest: None
Background: Resection of infrapatellar pad of fat (IPPF) is an ordinary step performed in primary total knee joint replacement (TKR) in approximately 88% to get a clearer field and eases patellar retraction to a side away during the surgical procedure. Objectives: The aim of this study was to evaluate the preservation versus resection of the IPPF regarding postoperative pain and range of movements in patients undergoing primary TKR. Materials and Methods: This was a prospective, case series study conducted in Erbil Teaching Hospital from March 1, 2018 till December 31, 2018. A total of 28 patients who underwent primary TKR were randomly allocated into two equal groups. In the first group the pad of fat was resected, whereas in the other group the pad of fat was preserved. The follow-up period of this study was 9 months. Patients of both groups were seen and followed up in the ward in the first 5 days of admission and seen again at the outpatient clinic at weeks 2, 6, 12, 24, and 36. The anterior knee joint pain and range of movement were recorded and observed by visual analog scale (VAS) score, knee score, and knee functional score. Results: Twenty-eight patients who underwent primary TKR were included in this study. Among them, 18 patients were women (64.28%) and 10 were men (35.72%). The mean age of the patients was 63.42 years ± 4.31 years, ranging from 56 to 71 years. Improved postoperative VAS score of the IPPF resection group (6.28 ± 0.91) and preserved group (5.92 ± 0.82) were observed (P < 0.045) at the 6 months of follow-up. Improvement in the degree of flexion observed in the IPPF preservation group over the resected one (P < 0.0060), with either no statistical differences were noticed of the final Knee Society Scores or the functional scores of the two groups, (62.78 ± 4.91) and (50.07 ± 5.80) of the IPPF resected group, (64.57 ± 5.54) and (52.14 ± 5.08) of the IPPF preservation group with both scores (P = 0.059 and 0.850), respectively. Conclusions: Preservation over resection of the IPPF during primary TKR decreases the postoperative anterior knee joint pain. Consequently, no significant changes were observed regarding the knee joint functionality.
Keywords: Infrapatellar pad of fat, resection versus preservation, total knee replacement
|How to cite this article:|
Fayyadh WK, Hwaizi L, Musa LO. Short-term comparison between resection and preservation of the infrapatellar pad of fat in patients undergoing primary total knee replacement. Med J Babylon 2021;18:316-21
|How to cite this URL:|
Fayyadh WK, Hwaizi L, Musa LO. Short-term comparison between resection and preservation of the infrapatellar pad of fat in patients undergoing primary total knee replacement. Med J Babylon [serial online] 2021 [cited 2022 Aug 8];18:316-21. Available from: https://www.medjbabylon.org/text.asp?2021/18/4/316/332741
| Introduction|| |
Early total knee replacements (TKRs) were introduced to the orthopedic surgical community back in the early 1973 by Insal and others, with femoral bicondylar modules that sacrifices most of the knee joint structures with the cemented femoral and tibial stems which ensures the long-term survival ship of that design.
The aim of the replacement procedure is to restore, as far as possible, some of the preinjury or prearthritic normal range of movement and to decrease the severity of pain. The limitation of the replacement procedure is the use of metals and polyethylenes that are harder and less flexible and never reach the biological material of the knee joint.
Nowadays many new designs are introduced to the market. These designs have more anatomical modules that mimic the femoral condyles and other modules that are custom-made to meet each individual patient requirement with the improvement of the type of the alloy used in manufacturing these prostheses and also the polyethylene inserts with the type of cement that is enforced with antibiotics.
Osteoarthritis that mainly affects the knee joint with increasing of age causing severe pain and immobility is a strong indication for replacement depending on the stage by Kellgren–Lawrence Grading System of knee joint osteoarthritis, and all these factors increase the incidence for TKR in the recent decades. Rheumatoid arthritis and traumatic damage to the femoral and tibial surfaces also indicate the patients to undergo TKR with a higher success rate to restore some of knee joint mobility and decrease the intensity of pain after the operation.
Patients with osteoarthritis will get much benefit from knee joint replacement especially with synovectomy and excision of arthritic surfaces that were already degenerated and eroded.,, The success rate of the replacement procedure with the overall patient’s satisfaction is very high and would reach more than 81%–89%,, with improved mobility and decrease in the intensity of pain and accomplishment of the daily activity as compared with the era before the replacement procedure. Recently, many surgical approaches have been developed to ease the procedure of TKR and these approaches can meet the variation of knee joint anatomy that differs from one patient to another.
Anteromedial or anterolateral approaches to the knee joints, have to dissect through the infrapatellar pad of fat (IPPF), in order to reflect the patella to the medial or lateral side depending on the type of surgical approach used during the replacement procedure.
Excision or preservation of the IPPF was based on the surgeon preference depending on the size of the fat pad and the amount of tibial surface that is reachable by the surgeon and the ability to reflect the patella with patellar tendon to a side away, nevertheless the emerging evidence of preservation of this pad might decrease postoperative knee pain and may enhance the range of movements.
The IPPF acts as a cushion between the patellar tendon and the anterior tibial plateau and can hinder the exposure of the surgical field in TKR. There is some evidence that excision of this pad of fat may lead some complications such as patellar mall tracking, may decrease patellar bone vasculature, and might lead to fracture,, and anterior knee pain. Other research suggests that excision of this pad might lead to a dead space that can lead to fibrous tissue, which may cause functional difficulties., These evidences are inconclusive, many recent systemic reviews found mixed results on the topic of pain and functionality and advised for more randomized controlled trial.
The main goals for patients to undergo TKR are to restore some of the joint mobility due to restoration of the mechanical axis with preservation of the joint line and to ease the pain as a result of excision of the arthritic surfaces and restoration of the collateral ligaments balance of the knee joint.
Many orthopedic surgeons tend to preserve the IFPP of fat during primary TKR due to its beneficial degree in improvement of all result parameters, including the anterior knee joint pain and the degree of improvement in the range of motion of the replaced knee joint.
| Materials and Methods|| |
Study design and setting
This was a short-term prospective comparative study conducted at Erbil Teaching Hospital from March 1 till December 30, 2018.
A total of 28 patients who underwent primary TKR were enrolled for the study. The study group consisted of two randomly divided groups, A and B, by selecting a pole paper that is given before the surgery to select preservation or excision of the pad of fat. The first 14 patients allocated to group A underwent resection of the IPPF and the other 14 patients allocated to group B had the pad of fat preserved during primary TKR using the posterior stabilized prosthesis [Table 1].
The inclusion criteria of the study included the following:
- Patients with symptomatic knee joint having grade 3 or 4 in Kellgren–Lawrence Grading System of knee joint osteoarthritis.
- Patients who failed conservative treatments for more than 3 months.
The exclusion criteria of the study included the following:
- Patients with a history of knee joint infection or remote serious infection.
- Patients with a history of comorbidity that hinders the TKR procedure.
- Patients with valgus knee joint deformity or rheumatoid arthritis of the knee joint.
- Patients who needed revision TKRs.
- Patients with posttraumatic knee arthritis or knee joints known to have ruptured collateral ligaments.
Detailed history was taken from each patient, and clinical examination including general physical examination and local examination of the affected knee joints, ipsilateral hip, and spine.
Full laboratory investigations were done including complete blood count, fasting blood sugar, renal function test, urinalysis, bleeding profile, erythrocyte sedimentation rate, C-reactive proteins titer, hepatitis, and AIDS virology screening tests. Patients were sent for medical and anesthetic consultations according to their medical conditions.
Each patient was sent for preoperative anteroposterior and lateral knee joints radiograph that was performed with the patient in standing position to predict preoperatively the size of the prosthesis and the condition of the joint regarding degree of deformity and osteophytes position for intraoperative releasement.
The whole procedure was explained to the patient and all the patients enrolled in the study gave and signed an informed written consent form.
All the patients admitted on the day of surgery and received the first dose of antibiotics 1 h before the surgical operation. The patients received two doses of tranexamic acid 10 mg/kg, the first dose 15 min before the inflation of tourniquets, and the second dose 10 mg/kg were installed in the knee joint before the closure (these are measures taken intraoperatively for each case of the two groups). The procedure was performed with the aid of pneumatic tourniquet. The patient was lying in supine position with the use of lateral support and bed support to aid the position of the knee joint kept in 90–110 of flexion during the operation when needed.
All the patients were operated by the same surgeon. The knee joint was approached through the anterior parapatellar approach, where the patella could be reflected laterally with excision of a thin layer of synovium only. A dense network of superficial vascular anastomosis appears just in the center of the pad of fat, which contributes branches of the inferior genicular artery that run in the posterior part of the patellar tendon. Patelloplasties were done for each patient’s patella of the two groups with excision of the femoral and tibial osteophytes, the knee joints were closed over a suction drain were to be removed after 48 h postoperatively.
The follow-up period of this study was 6 months. Patients of both groups were followed during the first 5 days of admission and seen in outpatient clinic at weeks 2, 6, 12, and 24. All the patients had physiotherapy course starting from the first postoperatively day, extending to week 3.
The degree of flexion and extension of the sample were assessed. Visual assisted scale for pain and the functionality of the knee joint were also assisted by knee score system, functional knee score system preoperatively, and postoperatively at week 24. Patients were asked to rate their degree of pain subjected at the knee joint by selecting a number on a VAS chart.
The Knee Society Score (KSS) system. It is the subjective part of the scoring system used in evaluating the knee joint for pain, total range of flexibility, stability, alignment, fixed flexion deformity, and extension lag. The score records the values as poor (<60), fair (60–90), good (70–90), and excellent (>80) on a 0–100 scale.
Function score system. It is the subjective part of the KSS measuring the patient skills such as walking, climbing stairs, and using walking aid.
Data were analyzed by using the Statistical Package for the Social Sciences software program, version 21.0 and by using the statistical function of the Microsoft Excel 2010 for Windows. Descriptive statistics and the observation were presented as mean, frequencies in number, percentage, and standard deviation (SD). Student’s t test of two independent samples was used to compare two means. A value of P ≥ 0.05 was considered statistically significant. Finally, the results and findings were presented in tables and figures with an explanation for each using the Microsoft Word program.
| Results|| |
A total of 28 patients who underwent primary TKR were included in this study. Among them, 18 patients were women (64.28%) and 10 were men (35.72%). The mean age of the patients was 63.42 years ± 4.31 years, ranging from 56 to 71 years. The median age was 63.5 years.
Of 14 patients in the resected group (group A), 5 patients were men (35.71%) and 9 were women (64.29%). The mean age was 64.62 ± 4.48 years. In the reserved group (group B), 4 patients were men (28.57%) and 10 patients were women (71.43%). The mean age was 62.21 ± 3.92 years.
Six right knee joints (42.85%) were replaced and eight left side (57.15%) in group A with a mean duration of 4.07 ± 1.59 years of pain and stiffness symptoms. There were 4 right side knee joints (28.57%) and 10 left sides (71.43%) with a mean duration of symptoms of 4.21 ± 1.61 years.
Anterior knee joint pain, which is defined as the pain at the anterior site of the knee with the activity of the patient of walking and going up and down stairs or changing the position of the knee or disturbing pain that affects the daily life activity, was assessed by VAS. The VAS scores for the resected group were 6.28 ± 0.91, whereas the VAS scores for preserved group were5.92 ± 0.82 [Table 2].
The mean preoperative flexion degree in the resected group was 96.57 ± 6.67 degrees compared to 6 months postoperative flexion (103.07 ± 7.82) degrees while the preserved group were the pre- and postoperative degree of flexion were (98.78 ± 7.19) and (107.85 ± 75.84), respectively [Figure 1].
|Figure 1: Degree of pre- and postoperative flexion of the resected and preserved groups|
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The mean pre- and postoperative degrees of extension in the resected group were 3.41 ± 1.48 and 4.40 ± 1.52, whereas the mean pre- and postoperative degrees of extension in the preserved group were 3.42 ± 1.58 and 4.67 ± 1.18 [Table 3].
The functionality of the replaced knee joint was assessed preoperatively and at week 24 by the KSS and functional knee score. The resected group preoperatively and at 24 weeks showed knee scores of 46.85 ± 4.47 and 62.78 ± 4.91, respectively, with functional scores of 42.14 ± 3.23 and 50.07 ± 5.80, respectively [Figure 2]. However, the preserved group preoperatively and at 24 weeks showed knee scores of 46.07 ± 5.51 and 64.57 ± 5.54 with functional scores of 44.46 ± 3.65 and 52.14 ± 5.08, respectively [Figure 3].
|Figure 2: Knee score of the resected and preserved groups at preoperative era and 6 months postoperatively|
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|Figure 3: Functional score of the resected and preserved groups at preoperative era and 6 months postoperatively|
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| Discussion|| |
In this prospective, comparative study, the collected data samples were evaluated and analyzed using multiple parameters such as the pre- and postoperative degree of flexion and extension, the intensity of pain by the VAS score, and the functionality of the knee joint by the KSS and function score.
The most common age group of patients in our study was 56–71 years with mean age of 63.42 years. In White and Melhuish’s study, the mean age of the patients was 67 years, suggesting that patients in the demographic area will progress early to severe osteoarthritic changes of the knee joint that requires TKR younger to those in White and Melhuish’s samples.
The mean score in this study for the anterior knee joint pain using the VAS score chart of the resected pad of fat group was 6.28, whereas the mean score was 5.92 for those with the preserved pad of fat group at 6 months with P = 0.045. White and Melhuish found a significant reduction in the pain at 6 months post-TKR procedure, whereas Meneghini et al. found a significant reduction in pain at 1 year postoperatively. A randomized study conducted by Pinosornsak et al. over 90 patients divided into two groups also found a significant pain reduction of the IPPF preserved group over the resected one (8.3% vs. 0%, P = 0.03). Macule et al. found progressive postoperative pain improvement at follow-up visits beyond the first year. Although immediate postoperative pains were significantly more severed in the resected group, the preserved group showed more anterior knee joint pains at sixth months as compared with the resected one (76% vs. 47.6%, P < 0.05).
Statistically non-significant result (P = 0.07) was found by the meta-analysis conducted by Zhang et al., where seven studies involving 2734 patients (3258 knees) were investigated for the severity AKP of the IPPF resection and preservation groups within the first two postoperative period until 12 months of follow-up, thus showing decrease of AKP of the preserved group over the resected one.
Seo et al. did not identify any differences in the pain intensity between the two groups, suggesting that soft-tissue preservation may not be enough to offer pain relief during the postoperative period after contemporary TKR.
El-osta et al. found that retaining of the Hoffa pad showed increase in the range of motion from 5 to 10 degrees post-TKR, with a decrease in TKP. Our study also found mild improvement in the degree of flexion and extension of the preserved group as compared with the resected one (P = 0.006 and 0.005), respectively. Macule et al. observed no difference in the range of motion between the resected and preserved groups of the OA patients who underwent TKR (P > 0.05). Similarly in a retrospective study on 1055 primary total knee arthroplasties performed on 720 patients, Meneghini et al. found that there is no significant effect on range of motion between the two groups.
A significant improvement in the KSS and the function score was seen in our study of the IPPF preservation group (P = 0.001 and 0.004). However, no statistically significant difference was observed between the two groups regarding the knee joint functionality (P = 0.059 and 0.85).
Meneghini et al. also found no significant changes in the knee and function scores (P = 0.724 and 0.678) when compared IPPF resection group with the preserved one. Pinosornsak et al. found no changes in the mean of KSSs and functional subscore at 1 year of postoperative follow-up. Moderate evidence for no difference in range of motions was also found by a systemic review conducted by White and Melhuish when compared resection group with the preservation one. Final KSS and function score of the two groups investigated by Seo et al. were also found to be statistically insignificant. Similarly, Van Beeck et al. observed no differences in knee function and range of movement.
| Conclusions|| |
Preservation over resection of the IPPF during primary TKR decreases the postoperative anterior knee joint pain. No significant changes were observed regarding the knee joint functionality, so we recommend excision of the pad of fat if required during the replacement procedure as the surgeon recommendation.
Ethical policy and institutional review board statement
The study was conducted in accordance with the ethical principles that have their origin in the Declaration of Helsinki. It was carried out with patient’s verbal and analytical approval before the procedure is performed. The study protocol and the subject information and consent form were reviewed and approved by a local ethics committee.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]