الفهرس 
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Abstract
Osteoarthritis of the knees is one of the most common joint diseases encountered in orthopaedic practice. The exact cause of osteoarthritis is not yet well understood. Nevertheless, mechanical overload cannot be ignored as a causative factor, which is obviously posing deleterious effects on malaligned knees. Realigning osteotomy provides the ability to decrease the load on the diseased compartment and shift this extra load to the non-diseased one by restoring the proper alignment. This potentially prevents the process of cartilage degeneration as a part of osteoarthritic process. Additionally, this may alleviate the biomechanical stresses on cartilage reforming, meniscal repair and ligament reconstruction procedures and thus augmenting their success rates. Perhaps, it is arguable whether to perform corrective osteotomy or lean towards arthroplasty which potentially carries quicker functional outcomes. However, osteotomy preserves the native joint without compromising the patient’s level of activity and delays the need for arthroplasty. On the other hand, arthroplasty from the start in a relatively young and active individual, will significantly decrease the patient’s level of activity and will need revision arthroplasty earlier, possibly after the same time as osteotomy. Biplanar in comparison to monoplanar osteotomy has the advantages of less incidence of patella infera, correction of both coronal and sagittal malalignment simultaneously while ensuring greater surface area for bone healing and providing more mechanical stability that averts loss of correction. The advent of locking plates has improved the outcomes of open wedge high tibial osteotomy significantly in terms of better stability allowing almost immediate mobilization, better healing potential and less incidence of loss of correction as opposed to non-locking fixation devices.
The aim of this study was to evaluate the results of biplanar valgus open-wedge high tibial osteotomy for medially arthritic varus knees fixed by locking plate.
Thirty-three varus knees (31 patients, 2 of them had bilateral MOWHTOs) with MCOA were operated upon during the period of 2015 to 2018 at Elhadra University Hospital. They all had MOWHTO using biplanar technique and fixed by locking plates (Tomofix™ plate). We compared the data fetched preoperatively (at day 0 = D0) with data one year or more after surgery with a mean of 14.5 months (at year 1=Y1). The mean age was 34.82 ± 8.74 years old, 23 were males while others were females. 17 were right knees and 16 were left. Types of occupation were; 14 as light, 14 as medium and 5 as heavy jobs. 22 were non-sportive and 11 were recreational athletes. 9 patients were normal weight while 24 were overweight. 26 were non-smokers while 7 were smokers. 3 patients were diabetic and 2 were perceived as treated HCV infection. 22 had medial meniscal injury and 5 had ACL injury. According to Outerbridge classification of articular cartilage; 11 were grade 1,16 were grade 2 and 6 were grade 3. Only 15 patients received AIBG. According to MCOA K-L scale; 10 were grade 3, 11 were grade 2, 9 were grade 1 and 3 were grade 0. 11 knees were grade 1 LCOA and 12 were grade 1 PFOA, while the rest were grade 0 for both. The mean LDFA was 91.45 º ± 1.66 º.
Arthroscopy was performed routinely at the start to confirm our diagnosis of MCOA and check on the integrity of both lateral and patellofemoral compartments. A 4-6 cm vertical incision was used. Biplanar Osteotomy was performed in the standard manner with the horizontal limb normally 4 cm distal to the medial joint line almost at the level of the lower end of the tibial tuberosity occupying the posterior two thirds of the medial aspect of the tibia, aiming at the cranial one third of head fibula aka outside proximal tibifibular joint, whereas the oblique vertical limb occupied the anterior third exiting at an angle of 110 degrees to the horizontal limb. The horizontal limb should keep a 10 mm of intact cortex laterally acting as a hinge, while the ascending oblique limb was cut leaving no lateral cortex that time. Internal fixation was done by the TomoFix™ plate. The knee was supported by a hinged knee brace. Generally, the patients were allowed to perform full range of motion from the start, nonetheless, weight bearing was not allowed for 6 weeks. Afterwards, partial weight bearing was permitted for another 6 weeks and then gradual full weight bearing started onwards.
As for the clinical results, WOMAC and Cincinnati scores were used preoperatively and 1 year postoperatively. The mean WOMAC value was 51.06 ± 26.11 and then dropped to 20.03 ± 17.41. The difference was statistically significant (p-value was <0.001). The mean Cincinnati score was 40.36 ± 19.28 at D0, then 81.88 ± 14.45 at Y1. The rising pattern from D0 to Y1 was significant statistically (p-value was <0.001).
For radiological results, the mean amount of correction was 10.27 º ± 2.97 º. The mean MPTA changed from 81.94 º ± 3.33 º to 92.21º ± 1.62º. The mean FTA was 11.91 º ± 3.16 º at D0 which was shifted to 1.06 º ± 1.43 º at Y1. A statistically significant decreasing pattern of mean JCA from 2.36 º ± 1.43 º to 1.82 º ± 1.29 º. The mean JLO was -0.33 º ± 1.38 º and changed to 1.94 º ± 1.14 º. The mean tibial length changed from 386.7 ± 28.18 mm to 395.7 ± 29.31. Five of our patients had chronic ACL insufficiency. The mean TS for the 28 patients was 11.11 º ± 2.54 º and changed to 11.18 º ± 2.51 º and this was statistically insignificant. Regarding the PH, there was a statistically significant decreasing tendency from a mean of 1.02 ± 0.10 to 0.97 ± 0.10. LPT showed a statistically significant decrease, although quite small, from 10.48 º ± 4.32 º to 9.45 º ± 4.27 º. A statistically significant, yet minimal, decreasing pattern of CA from 17.76 º ± 7.35 º to 17.11º ± 7.37º. LPS showed a slight increase from a mean of 10.72 ± 3.74 to 11.14 ± 3.76, which was not statistically significant.
MOWHTO using biplanar technique and fixed by the Tomofix™ plate without BG filling except in risky patients is a very efficient modality of treatment for adult patients suffering from medially arthritic varus knees in terms of clinical and radiological aspects. Patellar descent is a problem of MOWHTO that is more pronounced with larger corrections and/or in preoperative patella infera. Further studies are needed to confirm the benefits of the descending limb biplanar osteotomy over the ascending one as regards to decreasing or abolishing the resultant patellar descent that occurs with latter technique. Increasing age, female gender, smoking and overweight patients are all negative predictors for clinical outcomes.