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| ORIGINAL ARTICLE |
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| Year : 2022 | Volume
: 8
| Issue : 1 | Page : 40-46 |
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Focal dome condylar osteotomy: Early results of alignment of a combined intra- and extra-articular high tibial osteotomy
Ravi Bhadiyadra1, Aditya P Apte1, Milind Chaudhary2
1 Clinical Fellow, Centre for Ilizarov Techniques, Akola, Maharashtra, India
2 Director, Centre for Ilizarov Techniques, Chaudhary Hospital, Akola, Maharashtra, India
| Date of Submission | 19-May-2022 |
| Date of Decision | 11-Jun-2022 |
| Date of Acceptance | 12-Jun-2022 |
| Date of Web Publication | 30-Jun-2022 |
Correspondence Address:
Milind Chaudhary
Centre for Ilizarov Techniques, Chaudhary Hospital, Civil Lines, Akola - 444 001, Maharashtra
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jllr.jllr_19_22
Background and Aims: Extra-articular high tibial osteotomies reliably treat varus deformities seen in medial compartment osteoarthritis of knee (MCOA). Recently, attention has turned to the detection and treatment of intra-articular knee deformity to treat MCOA. Tibial condylar valgus osteotomy (TCVO) is an intra-articular osteotomy (IAO) that corrects the varus by elevating the medial tibial condyle and is fixed with a plate. TCVO improves joint line convergence angle (JLCA), spine edge angle (SEA), and spine vertical distance (SVD), which measure intra-articular deformity. It may undercorrect the mechanical axis to <50%. Focal dome condylar osteotomy (FDCO) is recently described and claims to correct both the intra- and extra-articular deformities in MCOA. We aimed to study the immediate results of FDCO and compare its efficacy with TCVO. Patients and Methods: We performed ten FDCO procedures on ten patients over the last year. The mean age was 57 years. We compared the results with a similar retrospective cohort of ten TCVO patients. Results: The mean preoperative (bo) mechanical axis deviation (MAD) in FDCO was −13.8% and improved to 51.6%. TCVO group had a similar mean postoperative (po) MAD of 43.5% (P = 0.38). Although 6 of 10 FDCOs had MAD >50%, only two of TCVOs crossed the midline. The mean bo medial proximal tibial angle in FDCO was 85.9° and improved significantly po to 93°. Hip knee ankle angle, ankle joint line orientation, and knee joint line orientation improved significantly as did JLCA, SEA, and SVD. Condylar plateau angle did not change. Conclusion: FDCO is an IAO with a vertical limb that passes through the lateral tibial spine and a medial curved limb. This single osteotomy can correct the intra-articular and extra-articular varus deformity. Although there was no significant difference in the correction of intra- and extra-articular deformity parameters between FDCO and TCVO, we feel that it was part of our learning curve. FDCO has the potential for better correction of the mechanical axis along with intra-articular deformities.
Keywords: Focal condylar dome osteotomy, high tibial osteotomy, medial compartment osteoarthritis, tibial condylar valgus osteotomy, varus knee
How to cite this article:
Bhadiyadra R, Apte AP, Chaudhary M. Focal dome condylar osteotomy: Early results of alignment of a combined intra- and extra-articular high tibial osteotomy. J Limb Lengthen Reconstr 2022;8:40-6 |
How to cite this URL:
Bhadiyadra R, Apte AP, Chaudhary M. Focal dome condylar osteotomy: Early results of alignment of a combined intra- and extra-articular high tibial osteotomy. J Limb Lengthen Reconstr [serial online] 2022 [cited 2023 Mar 27];8:40-6. Available from: https://www.jlimblengthrecon.org/text.asp?2022/8/1/40/349416 |
| Introduction | |  |
Medial compartment osteoarthritis (MCOA) is treated with high tibial osteotomies (HTO), correcting the varus deformities in the lower limb. Closing wedge,[1] open wedge,[2],[3] and focal dome[4],[5] are some osteotomies that correct the extra-articular varus of the upper tibia.
Intra-articular deformities arising from the knee joint also contribute to MCOA. Moderate to large varus mechanical axis deviation (MAD) visible as a dynamic varus gait and elicitable as mediolateral laxity of the knee suggests an intra-articular deformity. Joint line convergence angle (JLCA) and condylar plateau angle (CPA) confirm the intra-articular deformity.[6] Spine edge angle (SEA) and spine vertical distance (SVD), introduced recently, help monitor the changes after intra-articular osteotomies (IAO).[7]
The tibial condylar valgus osteotomy (TCVO) described by Chiba corrects the intra-articular deformity.[6],[8],[9] It reduces point loading of medial femoral and tibial condyles, increases weight-bearing area, and stabilizes the knee to relieve pain. Since this osteotomy passes through the knee joint at the level of the medial tibial spine, medial to the patellar ligament (PL), it frequently undercorrects the mechanical axis. Since it is generally accepted that a corrected mechanical axis improves long-term results, efforts have been underway to increase the lateral passage of the mechanical axis with TCVO.[8] Kuwashima et al.[10] showed how to calculate the need for an additional extra-articular osteotomy (EAO). This second osteotomy may be an opening wedge or a closing wedge fixed in the same plate as the TCVO or a distal dome, fixed with an Ilizarov fixator. The latter has effectively improved lateral passage of the mechanical axis, albeit with the inconvenience of wearing a fixator. The need to improve mechanical axis correction after an IAO without an additional osteotomy was obvious. Igarashi et al.[11] have possibly solved this problem by the focal dome condylar osteotomy (FDCO) in 2020. Although FDCO is similar to TCVO, it approaches the knee joint at the level of the lateral tibial spine (LTS), lateral to the PL, and hence should correct the mechanical axis to approximately 60% of the knee joint width. FDCO contrasts with TCVO, whose vertical limb is medial to the PL.
We reported the results of our early efforts with the FDCO over the past year. We aimed to focus on changes in the mechanical axis and parameters that measure articular incongruity. We also discussed the difficulties and learning curve with this elegant yet technically challenging intra-cum-EAO. We also compared its results with a similar cohort of patients who underwent a TCVO previously.
| Patients and Methods | | |
We performed ten FDCO in ten patients suffering from MCOA in our institute since April 2021. There were three right and seven left limbs. Nine were female, with a lone male patient [Table 1].
We took informed consent and institutional review board approval for this retrospective study of radiological measurements. We also performed a chart review to note any complications during and after surgery. Statistical analysis of the data was performed using MS-Excel. The t-test was used to compute the comparison of the means, and the significance level was set at P < 0.05.
Surgical technique
The FDCO is like a TCVO[6] and differs in a few details. We prepared and positioned the patient similar to that for TCVO. A medial and lateral patellar retinacular release was done for patellofemoral joint line pain.[12] The incision was extended medially beneath the tibial tuberosity (TT). The pes anserinus and superficial medial collateral ligament were elevated subperiosteally to expose the posteromedial tibia. A K-wire marked the LTS under the image intensifier (II). It was near the lateral border of the PL. With a sharp knife, the PL was gently elevated laterally from the TT, and the upturned lateral edge was temporarily sutured to its medial border.
In most cases, we limited this elevation to <20% of the PL footprint. Another vertical K-Wire marked the end of the vertical osteotomy line coming down from the LTS [Figure 1]a. A curved cutting jig was mounted on the CORA wire. A curved osteotomy was made with either a sharp osteotome or a reciprocating saw from the TT and extended medially, proximal to the superficial medial collateral ligament. Due to its curved dome shape, the osteotomy remained stable and retained bony contact when opened. The posterior cortex of the vertical limb was cut carefully under II control. Before opening the osteotomy, 1 mm and 1.2 mm K-wires were passed subchondral from medial and lateral sides to prevent the spreading of medial and lateral tibial condyles and protect the hinge. Two long, flexible wires were inserted from just below the lateral joint line, passing laterally to the vertical limb of the osteotomy. These wires prevented a fracture at the narrow lateral cortex just lateral to the TT [Figure 1]b. | Figure 1: (a) Clinical photograph depicting vertical limb of the osteotomy being made lateral to the patellar ligament; (b) vertical limb of osteotomy passes near lateral tibial spine. Curved osteotomy is directed medially from tibial tuberosity, ending above insertion of superficial medial collateral ligament. Two transverse K-wires protect hinge at joint level and prevent separation of condyles. Two additional K-wires inserted from lateral side to prevent fracture of narrow lateral cortex; (c) Lateral X-ray shows osteotomy fixed with locking plate. It shows a screw with spiked washer to prevent patellar ligament avulsion
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A manual valgus force gently opened the osteotomy, and an arthrodesis spreader kept it open. The mechanical axis was checked with II with a rod or radiolucent grid. When found satisfactory, the osteotomy was fixed with a locking plate. Since the PL was elevated laterally and its footprint narrowed, it could get avulsed with unrestrained knee flexion. A spiked washer and screw can prevent this [Figure 1]c. The wound was closed over a drain. All patients were mobilized, toe-touch weight-bearing for the first 3 weeks. They were later allowed, partial weight-bearing for the next 6 weeks, and full weight-bearing at around 9–12 weeks postsurgery.
Knee range of motion (ROM) was started from postoperative day 2. However, knee flexion beyond 30° was permitted after 4 weeks in patients needing more PL footprint elevation.
| Results | | |
FDCO improved the mean MAD from a preoperative (bo) −13.8% to postoperative (po) of 51.6% of the knee joint width [Figure 2]a and [Figure 2]b. Medial proximal tibial Angle (MPTA), hip knee ankle angle (HKA), knee joint line orientation (KJLO), and ankle joint line orientation (AJLO) all changed significantly. As expected, the mechanical lateral distal femoral angle did not change [Table 2]. The mean ΔMAD (amount of correction of MAD) was 65.4%. | Figure 2: (a) Preoperative full-length X-ray of a 62-year-old female with left MCOA, MAD is at −8%; (b) postoperative full-length X-ray after FDCO showing left lower limb MAD is at 72%. MCOA: Medial compartment osteoarthritis, MAD: mechanical axis deviation, FDCO: Focal dome condylar osteotomy
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 | Table 2: Alignment-deformity parameters of focal dome condylar osteotomy
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We recorded intra-articular deformity parameters and their change as summarized in [Table 3]. JLCA, SEA, and SVD changed. CPA did not change (P = 0.07). The results of a matched cohort of ten patients who underwent TCVO were similar [Table 4] and [Table 5]. JLCA and KJLO did not change significantly (P = 0.09 and P = 0.3) in the TCVO group. However, postoperative standard deviation and range were much lower for AJLO in FDCO than TCVO. | Table 3: Intra-articular deformity parameters of focal dome condylar osteotomy
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 | Table 4: Alignment-deformity parameters of tibial condylar valgus osteotomy
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 | Table 5: Intra-articular deformity parameters of tibial condylar valgus osteotomy
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There was no statistically significant difference between TCVO and FDCO based on the matched comparison of ten patients [Table 6]. | Table 6: Comparison of parameters between two groups (focal dome condylar osteotomy vs. tibial condylar valgus osteotomy)
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Complications
Superficial infection developed in one patient and was resolved by antibiotics. One patient had a wound breakdown, which resolved with regular dressing. One patient had a lateral cortex fracture, which required protected weight-bearing and eventually united without alignment change [Figure 3]. We could not improve the mechanical axis in our first patient, which went from bo MAD −2% to po MAD 9%. A few months after the osteotomy healed, we performed an infratuberosity focal dome osteotomy in a second surgery. We fixed it with an Ilizarov, which eventually corrected the MAD to 59% [Figure 4]a,[Figure 4]b,[Figure 4]c,[Figure 4]d. | Figure 3: AP X-ray depicting lateral cortical fracture which developed after early full weight-bearing in a 65-year-old patient. AP: Anterior posterior
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 | Figure 4: (a) Preoperative full-length X-ray of a 48-year-old female with left MCOA, MAD is at −2%; (b) postoperative FDCO full-length X-ray, MAD is undercorrected to only 9%. This was our first case of FDCO; (c) repeat osteotomy was performed after 5 months, as a distally convex focal dome, fixed with an Ilizarov fixator. MAD improved to 59%. Proximal fibular osteotomy needed to achieve angulation–translation of the focal dome; (d) four months after surgery Ilizarov fixator removed. Correction maintained at 59% of joint width. FDCO: Focal dome condylar osteotomy, MAD: mechanical axis deviation, MCOA: Medial compartment osteoarthritis
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| Discussion | | |
EAOs correct the mechanical axis to offer pain relief in MCOA. Heijens explained how JLCA could be corrected by the coronal hypomochlion.[13] Improving the HKA angle to 2° valgus is enough to shift loading away from the medial compartment, regardless of an intra-articular deformity. A distal femoral osteotomy combined with HTO maintains KJLO and may reduce JLCA.[14] However, such a double osteotomy extracts a double price in implants and physiology. Nakayama recommended staging the two osteotomies in elderly patients, again inconvenient.[15] Hence a single tibial osteotomy that does the job of two should prove advantageous.
Chiba[6],[9] described an IAO of the upper tibia where the predominant cause of MCOA was an intra-articular deformity. Their role is slowly being appreciated. We learned TCVO from Teramoto[16] in 2014 and have used it since then. We now understand how to look for and recognize intra-articular deformities causing MCOA by clinical and radiographic examination. Clinical signs include a large varus deformity, increased mediolateral laxity, and a dynamic varus gait. An increased JLCA and CPA help verify intra-articular deformity on X-rays [Table 3] and [Table 5]. There is also a moderate correlation between MAD <0% and a high CPA.[8] Hence, patients with a large varus MAD (<−10%) should be suspected to have an intra-articular deformity. We have previously reported[8] our experience of TCVO, which adequately corrected intra-articular deformity parameters but undercorrected the mechanical axis. We attempted to improve the mechanical axis correction by adding a second distal osteotomy, fixed with the Ilizarov fixator and called TCVO-I.[17]
Adding a second osteotomy may be considered a disadvantage. This second osteotomy may be an opening or a closing wedge. Both types can be fixed within the same locking plate.[10] However, a large varus needs an additional dome osteotomy performed distally and fixed with an Ilizarov fixator. We could improve the mechanical axis accurately using the Ilizarov but using the fixator may not be acceptable to all surgeons and patients.
An osteotomy that corrects intra- and extra-articular deformities, uses a locking plate for fixation, and corrects the mechanical axis beyond neutral would be more convenient for surgeons and patients.
In 2020,[11] Igarashi et al. described the FDCO, which corrects intra- and extra-articular deformities through a single combined vertical and curved osteotomy. It is similar to the TCVO, but its vertical cut is at the level of the LTS, and the horizontal cut is curved medially and retains bony contact. It is indicated when the CORA formed by the intended mechanical axis line passing through the LTS intersects with the mechanical axis of the tibia. The CORA was present near LTS in all our FDCO cases. FDCO does not alter limb length or worsen AJLO.
We wished to judge if FDCO could correct the intra-articular deformity and the mechanical axis beyond neutral. FDCO did improve the MAD to a mean of 51.6%, but it was not significantly different in a matched cohort of TCVO (43.5%, P = 0.12). Six of the ten FDCO patients achieved MAD ≥50%, whereas only two of the ten with TCVO did. While we were disappointed with the lack of statistical significance, we feel that the change in the mechanical axis is clinically relevant and enthuses us to improve our results with FDCO even further. We are new to this technique, possibly responsible for a lower mean change of MAD.
Challenges that may have prevented us from achieving better postoperative MAD include osteoporosis and inadequate soft tissue releases. A stout arthrodesis spreader can break the thin lateral cortex near the TT while opening a large wedge. We did use two 1.8 mm wires to protect the thin cortex [Figure 1]b. We may have inadequately released soft tissues posteromedially in some of our cases. The difficulty gauging the endpoint of any dome osteotomy has possibly contributed to the slight under correction.[18] Opening and closing wedge osteotomies have definite endpoints, whereas domes do not. We may be able to improve the mechanical axis with the FDCO as we master and flatten its learning curve.
IAO relieve pain by improving congruent contact between the medial and lateral tibiofemoral condyles. The resulting larger weight-bearing area reduces point loading in the medial compartment. The edges of medial and lateral condyles are elevated, measured by an increased SEA. The decreased SVD, which measures the lowering of intercondylar eminence, mildly stretches and stabilizes the cruciate ligaments.[7] CPA did not change significantly in TCVO or FDCO [Table 3] and [Table 5]. We have previously described the difficulties in measuring CPA accurately. SEA and SVD may not be diagnostic of an intra-articular deformity but accurately measure the change between pre- and post-operative status[7] [Table 3] and [Table 5].
We have reported our use of TCVO elsewhere and explained that we added a second distal dome osteotomy fixed with an Ilizarov fixator (TCVO-I) to improve the MAD. Although an effective strategy, it has come at the expense of wearing a fixator for 4 months.
The vertical limb of FDCO passes through the LTS, which corresponds approximately to the Fujisawa point or 60% of knee joint width. Elevating the PL laterally from the TT is necessary to allow a straight vertical osteotomy, which does not fracture the lateral tibial cortex. The PL is sutured to the lateral soft tissues after the osteotomy. A spiked washer was inserted in six of our ten FDCO patients to prevent avulsion of the narrowed footprint of PL [Figure 1]c. We did go slow with the knee ROM rehabilitation in our FDCO patients compared to TCVO patients. We have not experienced any avulsion of the PL in our patients.
The vertical limb of TCVO passes medial to the PL, which corresponds to 40% of the joint width. Hence, further elevation of the medial tibial condyle to better correct the mechanical axis could spread the tibial condyles apart, possibly damaging the anterior cruciate ligament (ACL) or changing the kinesiology of the knee. It may be presumed that CORA for the two osteotomies is different: more laterally for FDCO, making it easier to correct the mechanical axis beyond neutral. The PL stayed with the stable lateral fragment of TCVO but moved with the mobile medial fragment of FDCO.
Ogawa et al.[19] recommended not correcting MPTA to more than 95° to prevent stressing the ACL or patella-femoral cartilage. Only two of ten patients in each group had po MPTA >95°. AJLO improved to a similar extent in both osteotomies (P = 0.92). CPA did not change after surgery in both groups (FDCO P = 0.07, TCVO = 0.57), which reinforces our research that CPA cannot accurately diagnose or monitor intra-articular deformities. KJLO changed in FDCO (P = 0.02) but not in TCVO (P = 0.3), which we believe could reflect a greater change in overall alignment, though not reflected in the P values of MAD. JLCA reduced significantly in FDCO (P = 0.009) but not in TCVO (P = 0.09). However, in a yet unpublished larger cohort of TCVO patients we have studied, JLCA was also reduced significantly. The smaller sample size of this study does not reflect this change in JLCA in TCVO.
The major limitation of our study is the small sample size and less follow-up of the new osteotomy of FDCO. The comparison with the TCVO group was not randomized and was retrospective. We have also not measured any patient-reported outcomes in either group. The attempt merely measures the alignment changes in the newly described osteotomy.
| Conclusion | | |
Igarashi et al.[11] recently described the FDCO to correct intra- and extra-articular deformities through a single osteotomy. It has a vertical limb that passes through the LTS and a medially curved limb that rises above the superficial medial collateral ligament. It should correct the mechanical axis beyond the neutral or close to 60% without resorting to an additional EAO. We failed to demonstrate a statistically significant change in the postoperative MAD in FDCO compared with TCVO. However, it is clinically relevant and, with more experience, may allow us to correct large varus deformities with an intra- and extra-articular component through a single osteotomy without worsening either the knee or ankle joint orientation. Further experience and randomized trials with TCVO or other osteotomies may shed more light on the use of FDCO.
Acknowledgment
The senior author wishes to thank Dr. Tsuchiya for the help in understanding the surgical technique of focal dome condylar osteotomy.
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.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]
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