Advertisement

Editorial Commentary: Avoid Creating an Oblique Joint Line After an Opening Medial Wedge High Tibial Osteotomy

      Abstract

      A medial opening wedge high tibial osteotomy is a cost-effective procedure for younger patients with symptomatic medial compartment knee arthritis. A high rate of success can be expected, but excessive postoperative joint line obliquity is associated with inferior clinical outcomes. If preoperative planning predicts that the postoperative medial proximal tibial angle, the medial angle between the tibial anatomical axis and the joint line of the proximal tibia, will exceed 95°, a surgeon should consider performing a double-level osteotomy (combined proximal tibial and distal femoral osteotomies).
      High tibial osteotomy (HTO) has regained popularity as a surgical technique to correct a varus deformity and unload the medial compartment. It has been shown to be a cost-effective, joint-preserving treatment for younger patients with symptomatic medial compartment osteoarthritis.
      • Konopka J.F.
      • Gomoll A.H.
      • Thornhill T.S.
      • Katz J.N.
      • Losina E.
      The cost-effectiveness of surgical treatment of medial unicompartmental knee osteoarthritis in younger patients: A computer model-based evaluation.
      ,
      • Smith 2nd, W.B.
      • Steinberg J.
      • Scholtes S.
      • McNamara I.R.
      Medial compartment knee osteoarthritis: age-stratified cost-effectiveness of total knee arthroplasty, unicompartmental knee arthroplasty, and high tibial osteotomy.
      The traditional technique is a lateral closing wedge HTO, but I, like many surgeons, prefer a medial opening wedge HTO (MOWHTO), partly because of improvements in implant design, but also because it minimizes the risk of a postoperative peroneal nerve palsy, avoids a fibular osteotomy or resection of the proximal tibiofibular joint, and allows the desired angle of correction to be fine-tuned during surgery.
      • Murray R.
      • Winkler P.W.
      • Shaikh H.S.
      • Musahl V.
      High tibial osteotomy for varus deformity of the knee.
      Also, should conversion to a total knee arthroplasty be required subsequently, there is a lower risk of running into technical issues when converting a MOWHTO.
      • Han J.H.
      • Yang J.H.
      • Bhandare N.N.
      • et al.
      Total knee arthroplasty after failed high tibial osteotomy: a systematic review of open versus closed wedge osteotomy.
      Osteotomy survival after a OMWHTO is reported as 91% to 99% at 5 years and 84% to 92% at 10 years.
      • Lorbergs A.L.
      • Birmingham T.B.
      • Primeau C.A.
      • Atkinson H.F.
      • Marriott K.A.
      • Giffin J.R.
      Improved methods to measure outcomes after high tibial osteotomy.
      Despite this high chance of success, it is important to identify factors associated with a poor outcome, and one such factor is joint line obliquity.
      In their retrospective study titled “Excessively Increased Joint-line Obliquity After Medial Opening Wedge High Tibial Osteotomy Is Associated With Inferior Radiologic and Clinical Outcomes: What Is Permissible Joint Line Obliquity,” Kim, Lim, Choi, Jeong, Park, Shim, and Lee
      • Kim J.S.
      • Lim J.K.
      • Choi H.G.
      • et al.
      Excessively increased joint-line obliquity after medial opening wedge high tibial osteotomy is associated with inferior radiologic and clinical outcomes: What is permissible joint line obliquity.
      assessed the radiological and clinical outcomes of 135 Asian patients who had undergone a MOWHTO. Joint line obliquity was expressed as the medial proximal tibial angle (MPTA), the medial angle between the tibial anatomical axis and the joint line of the proximal tibia. The knees were grouped into quartiles based on the 3-month postoperative MPTA, with group IV containing knees with an MPTA ≥95.23°. The weightbearing line ratio (WBLR; the denominator being the width of the tibia and the numerator being the distance of the weightbearing line from the medial edge of the tibial plateau) was greatest in group IV, with a mean of 63.85%. There was also a significantly lower percentage of patients in group IV who attained the minimal clinically important difference for the Knee Society functional score and the SF-36 physical component summary at final follow-up (56-79 months after surgery).
      Thus, a postoperative MPTA ≥95.23° was associated with valgus over-correction and worse clinical outcomes than a MPTA <95.23°. Accordingly, the authors suggest performing a double-level osteotomy (combined distal femoral and proximal tibial osteotomies) if the predicted postoperative MPTA ≥95.23°.
      The authors are honest in admitting the limitations of their study, although one limitation that I feel they have underplayed is that the surgical technique was altered depending on the extent of the degenerative changes within the knee. The target WBLR was increased from 62% (the Fujisawa point) to 65% if there was severe degeneration in the medial compartment or if a medial meniscus repair was required, and the target WBLR was decreased to 55% to 60% if there was pathology in the lateral compartment. Although this aligns with contemporary osteotomy practice, the variability in the target WBLR may have influenced the differences in clinical outcome between the groups. Because the authors showed that there was a positive correlation between the postoperative MPTA and the postoperative WBLR and, and because patients with severe medial degeneration had a greater target WBLR, it then follows that patients with a postoperative MPTA ≥95.23° would be more likely to have severe medial degeneration and possibly inferior clinical outcomes.
      Having said that, the findings reported by Kim et al.
      • Kim J.S.
      • Lim J.K.
      • Choi H.G.
      • et al.
      Excessively increased joint-line obliquity after medial opening wedge high tibial osteotomy is associated with inferior radiologic and clinical outcomes: What is permissible joint line obliquity.
      correspond with what has already been published on joint line obliquity. Other retrospective cohort studies have shown that a postoperative MPTA greater than 95° is associated with worse clinical outcomes
      • Akamatsu Y.
      • Kumagai K.
      • Kobayashi H.
      • Tsuji M.
      • Saito T.
      Effect of increased coronal inclination of the tibial plateau after opening-wedge high tibial osteotomy.
      • Song J.H.
      • Bin S.I.
      • Kim J.M.
      • Lee B.S.
      What is an acceptable limit of joint-line obliquity after medial open wedge high tibial osteotomy? Analysis based on midterm results.
      • Park J.G.
      • Han S.B.
      • Jang K.M.
      Association of preoperative tibial varus deformity with joint line orientation and clinical outcome after open-wedge high tibial osteotomy for medial compartment osteoarthritis: A propensity score-matched analysis.
      or more frequent lateral compartment pain.
      • Kim G.W.
      • Kang J.K.
      • Song E.K.
      • Seon J.K.
      Increased joint obliquity after open-wedge high tibial osteotomy induces pain in the lateral compartment: A comparative analysis of the minimum 4-year follow-up outcomes using propensity score matching.
      Goshima et al.
      • Goshima K.
      • Sawaguchi T.
      • Shigemoto K.
      • Iwai S.
      • Fujita K.
      • Yamamuro Y.
      Comparison of clinical and radiologic outcomes between normal and overcorrected medial proximal tibial angle groups after open-wedge high tibial osteotomy.
      reported that a postoperative MPTA of 95° or more did not affect the clinical outcomes, although it may be pertinent to note that their cohort was relatively old (the mean age was 63 years).
      The theory is that joint line obliquity leads to inferior clinical outcomes due to increased shear forces. Indeed, Nakayama et al.
      • Nakayama H.
      • Schröter S.
      • Yamamoto C.
      • et al.
      Large correction in opening wedge high tibial osteotomy with resultant joint-line obliquity induces excessive shear stress on the articular cartilage.
      used a 3-dimensional finite element model to show that joint line obliquity (in this case, the angle between a line tangent to the tibial plateau and a line parallel to the ground) of more than 5° induced excessive shear stress in the tibial articular cartilage.
      So, it seems prudent to avoid creating a postoperative MPTA of greater than 95°, which may mean that an isolated OMWHTO is not always the best option. Feucht et al.
      • Feucht M.J.
      • Winkler P.W.
      • Mehl J.
      • et al.
      Isolated high tibial osteotomy is appropriate in less than two-thirds of varus knees if excessive overcorrection of the medial proximal tibial angle should be avoided.
      simulated an osteotomy on the radiographs of 303 patients with a mechanical axis of ≥3° varus, correcting the mechanical axis to 2° valgus. To avoid a postoperative MPTA greater than 95°, they found that a OMWHTO was feasible in only 57% of patients, and 33% would require a double-level osteotomy. This is echoed by the retrospective study of Akamatsu et al.,
      • Akamatsu Y.
      • Nejima S.
      • Tsuji M.
      • Kobayashi H.
      • Muramatsu S.
      Joint line obliquity was maintained after double-level osteotomy, but was increased after open-wedge high tibial osteotomy.
      who analyzed a cohort of knees with a predicted postoperative MPTA of greater than 95° and found that joint line obliquity was increased significantly from 1.4° to 6.3° in knees treated with an isolated OMWHTO but maintained in knees treated with a double-level osteotomy. What is uncertain is whether the maintenance of joint line obliquity justifies the increased complexity and morbidity of a double-level osteotomy. Well-designed, prospective studies are needed.
      In summary, the article by Kim et al.
      • Kim J.S.
      • Lim J.K.
      • Choi H.G.
      • et al.
      Excessively increased joint-line obliquity after medial opening wedge high tibial osteotomy is associated with inferior radiologic and clinical outcomes: What is permissible joint line obliquity.
      adds to the evidence that a predicted postoperative MPTA of greater than 95° should compel a surgeon to consider a double-level osteotomy. Where I work (in Suffolk, England) a phrase beloved of local tradesmen is “on the huh,” meaning not level, lopsided, or askew. In our trade of orthopaedic surgery, we should try not to leave our patients “on the huh.”

      Supplementary Data

      References

        • Konopka J.F.
        • Gomoll A.H.
        • Thornhill T.S.
        • Katz J.N.
        • Losina E.
        The cost-effectiveness of surgical treatment of medial unicompartmental knee osteoarthritis in younger patients: A computer model-based evaluation.
        J Bone Joint Surg Am. 2015; 97: 807-817
        • Smith 2nd, W.B.
        • Steinberg J.
        • Scholtes S.
        • McNamara I.R.
        Medial compartment knee osteoarthritis: age-stratified cost-effectiveness of total knee arthroplasty, unicompartmental knee arthroplasty, and high tibial osteotomy.
        Knee Surg Sports Traumatol Arthrosc. 2017; 25: 924-933
        • Murray R.
        • Winkler P.W.
        • Shaikh H.S.
        • Musahl V.
        High tibial osteotomy for varus deformity of the knee.
        J Am Acad Orthop Surg Glob Res Rev. 2021; 5e21.00141
        • Han J.H.
        • Yang J.H.
        • Bhandare N.N.
        • et al.
        Total knee arthroplasty after failed high tibial osteotomy: a systematic review of open versus closed wedge osteotomy.
        Knee Surg Sports Traumatol Arthrosc. 2016; 24: 2567-2577
        • Lorbergs A.L.
        • Birmingham T.B.
        • Primeau C.A.
        • Atkinson H.F.
        • Marriott K.A.
        • Giffin J.R.
        Improved methods to measure outcomes after high tibial osteotomy.
        Clin Sports Med. 2019; 38: 317-329
        • Kim J.S.
        • Lim J.K.
        • Choi H.G.
        • et al.
        Excessively increased joint-line obliquity after medial opening wedge high tibial osteotomy is associated with inferior radiologic and clinical outcomes: What is permissible joint line obliquity.
        Arthroscopy. 2022; 38: 1904-1915
        • Akamatsu Y.
        • Kumagai K.
        • Kobayashi H.
        • Tsuji M.
        • Saito T.
        Effect of increased coronal inclination of the tibial plateau after opening-wedge high tibial osteotomy.
        Arthroscopy. 2018; 34: 2158-2169.e2
        • Song J.H.
        • Bin S.I.
        • Kim J.M.
        • Lee B.S.
        What is an acceptable limit of joint-line obliquity after medial open wedge high tibial osteotomy? Analysis based on midterm results.
        Am J Sports Med. 2020; 48: 3028-3035
        • Park J.G.
        • Han S.B.
        • Jang K.M.
        Association of preoperative tibial varus deformity with joint line orientation and clinical outcome after open-wedge high tibial osteotomy for medial compartment osteoarthritis: A propensity score-matched analysis.
        Am J Sports Med. 2021; 49: 3551-3560
        • Kim G.W.
        • Kang J.K.
        • Song E.K.
        • Seon J.K.
        Increased joint obliquity after open-wedge high tibial osteotomy induces pain in the lateral compartment: A comparative analysis of the minimum 4-year follow-up outcomes using propensity score matching.
        Knee Surg Sports Traumatol Arthrosc. 2021; 29: 3495-3502
        • Goshima K.
        • Sawaguchi T.
        • Shigemoto K.
        • Iwai S.
        • Fujita K.
        • Yamamuro Y.
        Comparison of clinical and radiologic outcomes between normal and overcorrected medial proximal tibial angle groups after open-wedge high tibial osteotomy.
        Arthroscopy. 2019; 35: 2898-2908.e1
        • Nakayama H.
        • Schröter S.
        • Yamamoto C.
        • et al.
        Large correction in opening wedge high tibial osteotomy with resultant joint-line obliquity induces excessive shear stress on the articular cartilage.
        Knee Surg Sports Traumatol Arthrosc. 2018; 26: 1873-1878
        • Feucht M.J.
        • Winkler P.W.
        • Mehl J.
        • et al.
        Isolated high tibial osteotomy is appropriate in less than two-thirds of varus knees if excessive overcorrection of the medial proximal tibial angle should be avoided.
        Knee Surg Sports Traumatol Arthrosc. 2021; 29: 3299-3309
        • Akamatsu Y.
        • Nejima S.
        • Tsuji M.
        • Kobayashi H.
        • Muramatsu S.
        Joint line obliquity was maintained after double-level osteotomy, but was increased after open-wedge high tibial osteotomy.
        Knee Surg Sports Traumatol Arthrosc. 2022; 30: 688-697