|Year : 2020 | Volume
| Issue : 1 | Page : 2-6
Difficult primary total knee arthroplasty in varus knees - A case series study
S Naufal, BP Vinodkumar, CS Vikraman
Department of Orthopaedics, Govt Medical College, Paripally, Kollam, India
|Date of Submission||16-Oct-2020|
|Date of Decision||18-Oct-2020|
|Date of Acceptance||27-Oct-2020|
|Date of Web Publication||17-Nov-2020|
B P Vinodkumar
Government Medical College, Kollam, Kerala
Source of Support: None, Conflict of Interest: None
Introduction: Common indications for total knee arthroplasty (TKA) underwent in our hospital were severe grade osteoarthritis of the knee. The etiological factors are idiopathic, post-traumatic injury sequel, postinflammatory sequel, and metabolic conditions like gout and pseudogout. The risk factors include obesity, intraarticular fractures, and meniscal injuries. Materials and Methods: Study participants: A total of 12 cases were analyzed. Three of them were male and 9 were female. Four of them underwent cruciate-retaining and 8 cruciate sacrificing procedures. Discussion: The stability of the knee is a complex issue. The deformity and osteophytes affect the ligaments unequally because of different degrees of tightness or laxity in flexion and extension. We found that the most common difficulty arises in primary TKA was due to the medial tibial bony defect. The defects were secured with a graft fixed to the medial tibial condyle with or without utilizing screws. Physiotherapy was started from the next postoperative day onward. Conclusion: The TKA posed three challenges (1) Instability (2) Difficulty in soft-tissue balancing (3) The longevity of tibial tray. These three challenges were overcome by building the defect using bone graft.
Keywords: Bone graft, cruciate sacrificing, cruciate sparing, osteoarthritis, total knee arthroplasty
|How to cite this article:|
Naufal S, Vinodkumar B P, Vikraman C S. Difficult primary total knee arthroplasty in varus knees - A case series study. J Orthop Assoc South Indian States 2020;17:2-6
|How to cite this URL:|
Naufal S, Vinodkumar B P, Vikraman C S. Difficult primary total knee arthroplasty in varus knees - A case series study. J Orthop Assoc South Indian States [serial online] 2020 [cited 2020 Dec 3];17:2-6. Available from: https://www.joasis.org/text.asp?2020/17/1/2/300759
| Introduction|| |
In present-day practice, the common indications for total knee replacement arthroplasty are severe grade osteoarthritis of the knee. Females outnumbered the males in replacement surgeries in our institution. As early as possible, patients must perform their range of motion (ROM) exercises rigorously to attain functional ROM and to prevent contractures. To ensure the longevity of the replacement, patients must be motivated to modify their lifestyle. Moreover, they have to stop certain activities that may lead to failure, like running, heavy lifting, etc., and encourage certain activities such as walking, bicycling, and swimming.
Idiopathic, posttraumatic injury sequel, postinflammatory sequel, and metabolic conditions like gout and pseudogout. The risk factors include obesity, intraarticular fractures, and meniscal injuries. We have many patients who have associated foot deformities like hallux valgus or varus, flat foot who presented with severe osteoarthritis in their latter part of life. The usual reasons for the failure of total knee arthroplasty (TKA) are malalignment of components, infection, soft-tissue instability, etc.
The common difficulties that could arise during the TKA are:
- Tight flexion and extension gap
- Tight in extension but loose in flexion
- Tight in flexion but loose in extension
- Severe varus and valgus deformity with the bone defect
- Tight patella and difficulty in everting the patella.
Here, we are discussing a bone defect in the tibia, which was filled with bone graft taken from the femoral cut.
| Materials and Methods|| |
Case series: 12 participants were included.
We have utilized the femoral cut wedges as bone grafts to build up the defect. In 2 cases, additional one screw to fix the graft and in 3 cases, 2 screws were used for the same. All the rest bony defects were stabilized by cutting a notch in the medial tibial condyle and then the bone graft was shaped in such a manner that it will stick on to the parent bone.
A 56-year-old female had bilateral tri-compartmental osteoarthritis of the knees. She underwent TKA of the right knee previously, where there was no bony defect. But now on the left side, there was a bony defect at the medial tibial condyle and the weight-bearing X-ray showed the medial instability very well. She had severe tri compartmental osteoarthritis with medial tibial condyle defect of the left knee and gross varus deformity [Figure 1].
The patient positioned in supine. A high tourniquet applied at 300 mms of Hg pressure. Two posts were placed one at the level of the tourniquet and the other at foot level. Under Epidural and subarachnoid block, the procedure was performed. A straight midline skin incision was made. Joint was exposed through a medial para-patellar arthrotomy, patella everted, and condyles exposed. Severe erosive changes of the tibial and femoral condyles were noted along with severe bone loss at the medial tibial condyle [Figure 2] and [Figure 3]. In this patient, we did posterior cruciate-retaining prosthesis after filling the defect with bone graft that has been taken from the femoral cut. Then, at 1 cm anterior to the femoral attachment of the posterior cruciate ligament (PCL) intramedullary drill hole was made for the femoral alignment guide. The guide is placed at 5° valgus, and cut was made with 8 mm depth. Anterior and posterior femoral cuts taken using the anterior referencing guide.
|Figure 2: Note the erosive changes over the femoral condyles and the severe bone loss of the medial tibial condyle|
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The tibia is then subluxed anteriorly; extramedullary tibial jig was placed along the long axis of the tibia. A 90° cut was made from the highest point of the less affected lateral tibial condyle, a lesser depth cut is made due to the elongated lateral soft tissue to avoid a large extension gap. The extension gap was checked just to confirm if an adequate cut has been taken or not. There was gross instability. The medial tibial condyle defect was filled with bone block taken from the femoral cut [Figure 4]. The tibial bone wedge was secured with the titanium cortical screw [Figure 5] before assessing the extension and flexion gap.
|Figure 4: Preparing tibia using osteotome to create trough for the bone block and the bone wedge kept which covers the defect over the medial tibial condyle|
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|Figure 5: Filling the medial tibial condyle defect using the bone wedge and securing the wedge using titanium cortical screw.|
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The flexion and extension gaps were assessed after taking a cut for proper placement of the graft and found to be equal and fit. Then, the tibial baseplate preparation and keeling were done [Figure 6] and [Figure 7].
|Figure 7: (a) Immediate postoperative X-ray. (b) One month follow-up X-ray. |
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A 3rd case also showing the buildup defect of the medial tibial condyle with graft and screws [Figure 9].
|Figure 8: (a) Weight-bearing X-ray AP view of both knees and lateral view to assess the instability of the knee. (b) Intraoperative figure showing the defect filled by graft and fixed with 2 screws|
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Follow-up of subjects
Cefuroxime was the antibiotic of choice for 5 days along with injection Tiniba for 3 days. The epidural catheter was removed on the 2rd day. From the 2rd onward, low-molecular-weight heparine was given for 3 days. Adequate hydration and mobilisation of calf muscles were ensured in view of the prevention of deep-vein thrombosis (DVT). Quadriceps exercise started from the 1st postoperative day onward. Flexion and extension of the knee started on the 3rd day onwards. The first case: She was discharged from the ward after stitch removal on the 10th postoperative day. One month follow-up was uneventful. She started walking after 6 weeks.
One male person developed alcohol withdrawal symptoms on the 3rd postoperative day. Managed him with the help of psychiatrist and discharged on the 12th day only. Another male person developed calf pain and his D-Dimer was high, so he was shifted to the intensive care unit (ICU). He was symptom-free by 7th day, but because of prothrombin time derangement kept ICU for 12 days, then shifted to ward by 18th day only he was discharged. A similar 2nd example is shown in [Figure 8].
All the difficult primary cases were protected with hinged knee brace and advised to weight bear only after 6 weeks only. Plain radiographs were used to monitor the metal and cement interfaces with the bone and to check for the integrity of the bone block, which was reconstructed.
Male: Female (%) = 30:70
Bone grafts obtained: Reshaped femoral cut in all the cases.
Stabilization of bone graft: Used one screw: 2 cases: Used 2 screws: 3 cases
All the rest bony defects were stabilized by cutting a notch in the medial tibial condyle and then the bone graft was shaped in such a manner that it will stick on to the parent bone.
Success rate: 100%.
Infection rate: NIL.
DVT: 1 case (8.3%).
| Discussion|| |
Importance of radiological evaluation: Along with clinical examination, radiological evaluation (antero-posterior [AP], lateral views and weight-bearing AP view) will help to assess the instability, bony deformity, and defect of femur, tibia, and patella. Skyline/merchant view will help to assess patella-femoral joint characteristics. Standing views showing hips, knees and ankles to assess alignment and to rule out extra-articular deformities of femur and tibia. In Indian scenario the patellae are very small and nonresurfacing patellae is a good option, even though a controversy exists there.
Here, in this TKA posed three challenges (1) Instability. (2) Difficulty in soft-tissue balancing and (3) Longevity of tibial tray. These three challenges were overcome by building the defect using bone graft.
There are two designs of TKA available, in the first design, the PCL is retained and the in the second, the PCL is sacrificed where a peg is built into the polyethylene liner. No significant differences have been found in the results of cruciate-retaining and cruciate-sacrificing total knee designs in the literature. Computer-assisted surgery allows for alignment checking precisely during surgery. All patients should be treated with low-molecular-weight heparin or aspirin, early mobilization and mechanical prophylaxis to prevent DVT., Ligament balancing is an integral part of cruciate-retaining TKA and depends on the correct alignment of the knee in flexion and extension. This alignment is done separately on the femur and tibia based on anatomic landmarks on the bone in extension and flexion, regardless of ligament contracture or stretching. The patellar groove is coplanar in the AP plane so that the patella is drawn smoothly through the groove as a rope is pulled through a pulley. In the extended position, the joint surface slopes medially approximately 3°. Tibial resection is perpendicular to the long axis of the tibia and mechanical axis of the lower extremity. The resection surface is 3° valgus to the articular surface. Femoral resection is perpendicular to the mechanical axis and 5° valgus to the long axis of the femur. The resection surface is approximately 3° varus to the articular surface. These 3° errors in the femoral and tibial surface resections compensate for one another and result in surface resections that are parallel to one another and perpendicular to the mechanical axis of the lower extremity. The stability of the knee is a complex issue. The deformity and osteophytes affect the ligaments unequally because of different degrees of tightness or laxity in flexion and extension.
The structures that can be released to correct varus deformity are osteophytes, deep medial collateral ligament (MCL) and menisco-femoral ligaments, postero-medial corner with semimembranosus, superficial MCL and pes complex and rarely PCL. To align the knee in the flexed position, the femoral surfaces are resected perpendicular to the AP axis of the femur. We have given 3° external rotation in the femoral cut to make the flexion-extension gap rectangular. The upper tibia is in 3° of varus anatomically, but the cut is made at 90°. The distal femoral cut is made parallel to the tibial cut, so the extension gap is made rectangular. When the femoral component is made externally rotated, it affects only the flexion gap, more bone is removed from the posterior condyle on the medial side and the flexion gap also becomes rectangular. Remember, all varus and valgus positioned tibial components will fail eventually.
When the knee is tight medially in extension only, the posterior portion of the MCL and possibly the posterior medial capsule are released. In this case, only the posterior portion of the MCL was released first. A curved 0.5-inch osteotome is used to do this by elevating the MCL portion. The osteotome is directed approximately 45° downward and tapped gently to release the posteromedial oblique fibers from the tibia and from the tendon of the semimembranosus.
When the knee is tight medially in flexion only, the anterior portion of the MCL is released. The taut anterior fibers are released sub periosteally. These fibers attach fairly far distally (8–10 cm), and the osteotome is passed far enough to release the anterior fibers completely. The attachment of the pes anserinus and posterior oblique fibers of the MCL are left intact.
If the flexion gap is a little loose, it is advisable to avoid further femoral resection. You can upsize the femoral component to match the extension gap. You can try further tibial resection only as the last option as it will lead to further laxity in flexion. If the flexion gap is tight downsize the femur and goes for thicker poly is a good option along with augmentation of the distal femur. If the femoral cut is more, it can lead to upward migration of joint line and patellar mal-tracking and global instability.
In this case, the postoperative period was uneventful. We have started low-molecular-weight heparin after removal of the epidural catheter on the 2nd postoperative day. On the 6th day stopped all antibiotics and anticoagulant injections and started oral nonsteroidal anti-inflammatory drugs. We did not start aspirin routinely. Physiotherapy started on the day of surgery itself. The common complications that can occur are the following..
- Aseptic loosening
- Polyethylene wear and osteolysis
- Patello-femoral problems: Subluxation, dislocation
- Peri-prosthetic fracture
- Quadriceps or patellar tendon rupture
- DVT and pulmonary embolus
- Medical complications: Heart attack, pneumonia, urinary infection
- Numbness around the incision
- Pain and Pes anserinus bursitis.
| Conclusion|| |
The TKA posed mainly three challenges (1) Instability. (2) Difficulty in soft tissue balancing. (3) Longevity of tibial tray. These three challenges were overcome by building the defect in the medial tibial condyle using bone graft with or without screws for securing the graft. Twelve cases were analyzed. One of the cases was a 56-year-old female with bilateral tri-compartmental osteoarthritis underwent TKA of the right side prior, now came for left knee surgery. She had severe osteoarthritis of bilateral knees; the right kn
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]