**3.4. Clinical results**

Accurately restoring the mechanical axis (MA) of the limb, aligning components, and properly balancing soft tissue—as already mentioned—are vital for the long-term success of TKA [1–6]. In the last three decades, a number of different surgical techniques have been described for TKA, in severe valgus deformed knees [1–6, 9–11, 18, 31–34]. The distal femoral cut at 3° only, instead of 5–7° that applies in varus knees, protects against under-correction. A slightly more varus result has been proposed during TKA for VD to counteract any tendency for the knee to shift back into valgus [31]. Miyasaka et al. in their 10- to 20-year follow-up study presented successful bony alignment in 75% of cases by having a postoperative valgus alignment between 2° and 7° [22].

Above and beyond, on the subject of ligament balancing, there is no consensus regarding the sequence in which the lateral elements should be released in valgus knees. Starting with Insall et al. [46], in 1979, who described a soft-tissue balancing technique in which the ITB was divided transversely above the joint line, while the lateral aspect of the capsule, the LCL and the POP tendon were detached from the lateral femoral condyle [9, 46]. The excellent or good results referred was 93%; with limited posterior subluxation (<3%) and 3.6% reoperation rate in 5 years [45] and 6.7% in 12 years [47].

Afterward, other researchers such as Keblish [11], Buechel [26] and Fiddian [27] recommended a lateral approach with or without TTO. Keblish preferred lateral approach in VD knees as it has a better view; it is direct, anatomical and more "physiological" technique according to his opinion that maintains soft-tissue integrity. In 79 cases, Keblish performed the "lateral release" as part of the approach and concluded that the patellofemoral tracking and alignment stability were optimized and medial blood supply preserved. Clinical experience also showed the approach to be more esthetic and the results objectively superior, that is why the lateral approach was recommended as the "approach of choice" for fixed VD in TKA. In that difficult group of patients, there were good to excellent scores in 94.3% of cases; whereas knee stability was enhanced with the use of nonconstrained prostheses [11].

Furthermore, Buechel recommended the lateral approach with TTO in order to regain neutral alignment in VD of up to 90° and then to correct the fixed external tibial rotation deformity [26]. Fiddian et al. performed the lateral approach with repositioning of vastus lateralis at closure, with good to excellent results in 25 cases. The knee ROM and VD restoration were achieved in all the 25 cases; apart from two cases that developed 10° and 15° of fixed flexion deformity. With the repositioning of vastus lateralis at the end, the normal patellofemoral tracking was also restored [29].

Whiteside proposed the sequential releases of the ITB, POP, LCL and the lateral head of gastrocnemius; and tibial tubercle transfer when the Q angle was >20° [27]. He referred mean valgus angle at 7° after surgery; but with no alignment or varus-valgus stability deterioration during the 6-year follow-up period. Nevertheless, in greater than 25° VD, knees had a tendency for increased posterior laxity. Lastly, Whiteside presented patellar subluxation and dislocation in less than 1% in the study [27].

[44]. A small bone plug with the attached insertion of the PCL, and the PLC is removed from the tibia and moved distally, securing it with transosseous sutures. In this technique, the MCL is

The advancement of the MCL from the epicondyle or a division and imbrication in order to tighten it can be performed in conjunction with the use of constrained condylar prosthesis [6].

Accurately restoring the mechanical axis (MA) of the limb, aligning components, and properly balancing soft tissue—as already mentioned—are vital for the long-term success of TKA [1–6]. In the last three decades, a number of different surgical techniques have been described for TKA, in severe valgus deformed knees [1–6, 9–11, 18, 31–34]. The distal femoral cut at 3° only, instead of 5–7° that applies in varus knees, protects against under-correction. A slightly more varus result has been proposed during TKA for VD to counteract any tendency for the knee to shift back into valgus [31]. Miyasaka et al. in their 10- to 20-year follow-up study presented successful bony alignment in 75% of cases by having a postoperative valgus alignment between 2° and 7° [22]. Above and beyond, on the subject of ligament balancing, there is no consensus regarding the sequence in which the lateral elements should be released in valgus knees. Starting with Insall et al. [46], in 1979, who described a soft-tissue balancing technique in which the ITB was divided transversely above the joint line, while the lateral aspect of the capsule, the LCL and the POP tendon were detached from the lateral femoral condyle [9, 46]. The excellent or good results referred was 93%; with limited posterior subluxation (<3%) and 3.6% reoperation rate

Afterward, other researchers such as Keblish [11], Buechel [26] and Fiddian [27] recommended a lateral approach with or without TTO. Keblish preferred lateral approach in VD knees as it has a better view; it is direct, anatomical and more "physiological" technique according to his opinion that maintains soft-tissue integrity. In 79 cases, Keblish performed the "lateral release" as part of the approach and concluded that the patellofemoral tracking and alignment stability were optimized and medial blood supply preserved. Clinical experience also showed the approach to be more esthetic and the results objectively superior, that is why the lateral approach was recommended as the "approach of choice" for fixed VD in TKA. In that difficult group of patients, there were good to excellent scores in 94.3% of cases; whereas knee

Furthermore, Buechel recommended the lateral approach with TTO in order to regain neutral alignment in VD of up to 90° and then to correct the fixed external tibial rotation deformity [26]. Fiddian et al. performed the lateral approach with repositioning of vastus lateralis at closure, with good to excellent results in 25 cases. The knee ROM and VD restoration were achieved in all the 25 cases; apart from two cases that developed 10° and 15° of fixed flexion deformity. With the repositioning of vastus lateralis at the end, the normal patellofemoral tracking was

Whiteside proposed the sequential releases of the ITB, POP, LCL and the lateral head of gastrocnemius; and tibial tubercle transfer when the Q angle was >20° [27]. He referred mean

stability was enhanced with the use of nonconstrained prostheses [11].

tightened by moving a bone block distally with its tibial insertion [45].

**3.4. Clinical results**

66 Primary Total Knee Arthroplasty

also restored [29].

in 5 years [45] and 6.7% in 12 years [47].

Conversely, Krackow [10, 40, 45] and Healy [48] recommended medial soft-tissue advancement or reconstruction combined with lateral release. To be more specific, Krackow and Mihalko [40] studied in cadavers the flexion-extension joint gap changes after lateral structure release for VD correction in TKA and concluded that in severe valgus deformities, the LCL should be considered first for release and the POP and ITB be used to grade the release. In their series of 99 TKA, the Grade I VD knees (based on Ranawat classification) were treated with lateral release versus the Grade II VD knees which were treated with ligament reconstruction procedures on the medial side. The 72% of the patients referred excellent results whereas 18% good, 7% fair, and 2% poor [45]. Healy et al. presented, in Grade II VD knees, lateral ITB release in combination with proximal MCL advancement with bone plug recession, with fully stable and functional ROM at 4–9 years follow-up [48].

Apart from Krackow cadaveric study, extremely interesting results published in 2001 by Peters et al. who studied the flexion-extension gap symmetry during sequenced release of the lateral structures in VD knees. It is concluded that complete release of the ITB at the joint line had a more profound effect on the extension than the flexion gap. On the contrary, complete release of the LCL/POP from the femur more profoundly affected the flexion than the extension gap; both of these release steps produced gap increases that were significant (7–12 mm). Selective fractional lengthening of the ITB, the PLC, and the POP tendon alone produced smaller magnitudes of correction, which more symmetrically affected flexion-extension gaps [49].

Above and beyond, in 2004, Politi and Scott referred, good-to-excellent results in TKAs with VD >15°, and achieved soft tissue balance, with a lateral cruciform retinacular release, and without LCL and POP release in 32 out of 35 cases [50]. In the remaining three cases, the extension gap balancing was achieved by adding, apart from the lateral cruciform retinacular release, the LCL and POP partial release. No further prosthetic constraint was necessary following these releases, and these knees have remained clinically stable at their latest mean 3.4-year follow-up despite the partial release of the LCL and its contribution to flexion gap stability [50].

Stern et al. accomplished ligamentous balancing in TKAs with VD >10°, with sequential releases from the lateral side of the femur and without MCL reconstruction, achieving 91% of good-to-excellent results. The postoperative axis alignment was 5–9° valgus [31]. Likewise, Laurencin et al. reviewed TKAs with 25° VD, where lateral retinacular release was accompanied by sequential lateral release achieving postoperative anatomic alignment between 0° and 10° valgus, in 96% patients [51].

In 2014, Chalidis et al. presented the results of 57 Grade II VD knees that underwent a primary TKA via lateral parapatellar approach with a global step-cut "coffin" type TTO over a 10-year period. Postoperatively, there was a significant improvement in knee extension, flexion, Knee Society Pain and Function Scores and WOMAC Osteoarthritis Index. Congruent patellar tracking was observed in all cases. So, the researchers concluded that lateral approach in combination with TTO is an effective technique for noncorrectable valgus deformed knee in TKA [52].

**3.5. The advantages of the anterolateral approach and the lateral balancing versus** 

The medial parapatellar release arthrotomy though suggested as a standard procedure in a varus knee does not represent the optimal approach in a severe and technically demanding VD knee [4]. That is because the release of lateral patellar retinaculae is necessitated in most VD cases in order to prevent patellar instability. The latter as accompanied with medial capsulotomy results in significant impairment of the knee extensor mechanism's blood supply [57]. Though if the knee joint is approached via a lateral parapatellar arthrotomy, release of the lateral retinaculae is integrated in the approach and patella vascularity is preserved as the medial side stays undisturbed [4, 10, 57]. Laurencin reported 12% of patella avascular necrosis in medial parapatellar approach for TKA in combination with extensive lateral retinacular release [51]. Miyasaka also reported only one case out of 108, in which a patella fracture occurred 3 years after surgery which was believed to be secondary due to avascular necrosis [31]. In Nikolopoulos et al. series, no patella fracture or avascular necrosis was observed [3, 4].

Primary Total Knee Arthroplasty in Valgus Deformity http://dx.doi.org/10.5772/intechopen.74114 69

Very important also in the knee extensor mechanism is the scar tissue due to previous knee's surgical operations. More specifically, scar tissue from previous tibial osteotomy makes patella's eversion problematic, and there is always a hazard for patellar ligament avulsion by forceful intraoperative retraction. Therefore, in order to protect the knee extensor mechanism, additional surgical techniques are needed either proximally (V-Y quadricepsplasty or "quadriceps snip") [58, 59] or distally to the patella with TTO [4, 6, 28, 34, 60–63]. We believe that the eversion of the patella is easily performed when a TTO is added to the lateral approach in primary TKA

Likewise, in a lateral capsulotomy, the extensor mechanism is displaced medially, and as the tibia rotates internally, offers an excellent exposure of the contracted lateral structures, thus facilitates their adjustment. This encourages more conservative releases and significantly, discourages unnecessary steps that may create instability [4, 11]. In contrast in the medial approach, the lateral displacement of the extensor mechanism increases the external tibial rotation, pushing the contracted PLC away from the operative field and consequently technical difficulties in balancing the valgus knee [11]. Analyzing the literature on the subject of TTO, it has been valuated as a highly beneficial and safe procedure in achieving gentle eversion of the patella [4, 6, 28, 35, 60–63]. Besides, it prevents tibia internal rotation during patellar eversion, which may

simplify proper positioning of the tibial component in severe valgus knees [4, 10, 63].

Furthermore, in a medial approach, the patella tracking is less than optimum and postoperative patellar problems are more common [10, 11, 27]. In opposition, the patellar tracking in a lateral approach is assured with the self-centering movement of the quadriceps-patellar tendon mechanism [11, 27]. In cases where a TTO is added, alignment of the extensor mechanism can be improved or adjusted when required, as osteotomy fixation at the end of the operation allows medial transfer of the patellar tendon insertion, eliminating in that way the postoperative patellar maltracking [4, 11]. In Nikolopoulos et al. series [3, 4], no patellar instability

with severe valgus deformity, offering excellent view [4].

**hazards of anteromedial approach**

Brilhault et al. also proposed in 2002 an interesting balancing way for VD knees by treating 13 patients with fixed VD of the knee with a semi-constrained TKA combined with advancement of the LCL by means of a lateral femoral condylar sliding osteotomy [42]. At follow-up of mean 4.6 years, the mean Knee Society Score improved from 32 to 88 and the functional score from 45 to 73 conversely. The mean tibiofemoral angle was corrected from 191° to 180°. There was no postoperative tibiofemoral or patellar instability and, in most knees, distal transposition of the lateral femoral condyle achieved satisfactory stable alignment [42].

Hadjicostas et al. used computer navigation in severe VD (>20°) knees in combination with an osteotomy of the lateral femoral condyle. The correct mediolateral balancing of the extension gap was confirmed by the navigation system during the operation time and before the final fixation of the lateral femoral condyle. The 15 knees were corrected to a mean of 0.5° of valgus (0–2°), with excellent mid-term results referred by the authors. Lastly, flexion of the knee statistical significantly also improved to a mean of 105° (90–130°) postoperatively, and the mean Knee Society score improved from 37 (30–44) to 90 points (86–94) [53].

As a consequence, the "outside-in" or the "inside-out" technique has been proposed by different surgeons with similar results, such as Keblish, Murray, Stern, Buechel [4, 8, 9, 11, 26, 29, 31]. Likewise, the "pie crust" technique has also been proposed by Ranawat as an alternative way of knee balance, plus Clarke through the taut PLC or ITB with the knee fully extended [36, 37, 54]. If the lateral release cannot sufficiently stabilize flexion and extension gaps, then the medial side of the joint should be addressed, in an effort to limit the degree of lateral softtissue release [4, 6]. Several techniques have been similarly described for successfully and safely "tightening" the incompetent MCL [10, 40, 48].

Taking into consideration firstly that many surgeons find it difficult to correct a VD by using a conventional alignment guiding system without also using a constrained implant; and secondly that a marked coronal femoral bowing deformity is easily missed [55, 56]. Huang et al. proposed, in 2016, that the use of a computer-assisted surgery (CAS) for an intra-articular bone resection is effective for increasing the accuracy and reproducibility of limb and component alignment with fewer outliers [55]. Both intra-articular bone resection and CAS are beneficial in Ranawat arthritic type-II VD knees with marked coronal femoral bowing deformity as with a rather high prevalence has been reported in Japan, China, Korea, India, Taiwan, Singapore, and Turkey. The marked coronal bowing deformity alters the relationship between the MA and anatomical axis (AA) of the femur, thereby affecting the postoperative MA and the placement of the femoral component [55, 56]. The most important Huang's et al. study finding was that CAS was more efficacious than intra-articular resection for facilitating a properly reconstructed MA, femoral component placement, and restoration of the joint-line in TKA on patients with marked coronal femoral bowing deformity. Nevertheless, CAS did not yield a better clinical outcome at a mean follow-up of 60.2 months [55].
