Background: The purpose of this study was to examine (1) timelines for return to sport and work following high tibial osteotomy (HTO), and (2) whether patients return to sport and work at levels similar to preoperative levels.
Methods: A systematic search was conducted across 3 databases (MEDLINE, Embase, and PubMed). Two reviewers independently screened the results for relevant articles. Data regarding patient demographics, indications, surgical technique, return to work and sport, and complication and failure rates were abstracted from eligible studies.
Results: Nineteen studies were included, involving 1,189 patients (64% male, 21% female, 15% unspecified) and 1,224 knees. Mean age was 46.2 years (range, 16 to 80 years). Opening-wedge HTO was most commonly used, followed by closing-wedge HTO and hemicallotasis. Mean follow-up was 65.4 months (range, 8 to 253 months). Overall, 87.2% of patients returned to sport postoperatively, and 78.6% returned at an equal or greater level. Among competitive athletes, 54% returned to competition. Overall, 84.5% of patients returned to work postoperatively, and 65.5% returned at an equal or greater level. Approximately 90% of patients who returned to work or sport did so within 1 year. The complication rate was 5.8%, with infection being the most common complication; 7.0% of patients progressed to a total knee arthroplasty at a mean of 6.7 years (range, 0.8 to 15 years) following HTO.
Conclusions: The majority of patients undergoing HTO return to sport and work, and most return within 1 year of the operation. Most patients return to sport at a level equal to or greater than the preoperative level. Approximately two-thirds of patients return to an equal or greater level of physical work.
Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
1Division of Orthopaedic Surgery, Department of Surgery (D.d.S. and O.R.A.), and Centre for Evidence Based Orthopaedics, Department of Clinical Epidemiology and Biostatistics (N.S.), Michael G. DeGroote School of Medicine (S.E. and C.E.H.), McMaster University, Hamilton, Ontario, Canada
2Division of Orthopedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
Osteoarthritis (OA) is a costly, burdensome disease for the health-care system and the individuals affected. Patients with OA often suffer from pain, activity limitations, and a reduced quality of life1. The first-line treatment for OA is conservative, through nonpharmacologic (e.g., orthotics, weight loss) and pharmacologic means (e.g., nonsteroidal anti-inflammatory drugs) aimed at reducing pain and mechanical symptoms, slowing progression of the disease, and optimizing function2-4. Because of the progressive nature of OA, long-term management may eventually lead to surgical treatment, in which total knee arthroplasty (TKA) is considered the gold standard5. Indications for TKA are end-stage knee OA confirmed by radiography and persistent pain refractory to conservative measures6. Although TKA is documented to improve functional outcomes in older populations, it is not ideal for younger individuals who are employed and active7,8. In fact, the failure rate leading to revision in patients of younger age (<60 years) is estimated to be twofold greater than that in older patients9. Furthermore, a greater risk of failure, alongside longer life expectancy, will likely lead to multiple revisions6,8,10.
In young patients who typically have higher physical demands such as participation in sports and employment, high tibial osteotomy (HTO) is preferred over arthroplasty in the treatment of unicompartmental OA8. According to previous literature, ideal candidates for HTO are 60 to 65 years of age, with isolated medial OA, good range of motion, and no ligamentous instability11,12. HTO is also often performed in association with meniscal transplantation, cartilage repair procedures, and knee ligament reconstruction1,13. HTO offers several advantages over TKA in younger patients, including preservation of the native joint and an absence of permanent activity restrictions such as those associated with TKA, in which activity modification may be required to achieve durability of the prosthesis. The aim of HTO is to realign the mechanical axis of the lower extremity to shift weight-bearing zones to nonaffected areas1. In this manner, damaged cartilage of the knee is off-loaded, thus decreasing pain, improving function, slowing knee deterioration, and potentially delaying the need for arthroplasty4. Several studies have demonstrated the benefit of HTO, including a study of 79 knees treated with HTO in which 80% of patients achieved a good or excellent result at the latest follow-up (5.8 years)14.
Numerous validated outcome measures exist to quantify success of such surgical procedures; these include the Knee Osteoarthritis Outcome Score (KOOS), survival rate, and time to revision. For patients who are young and active, however, the most important outcome may be return to sport and/or work following surgical treatment, and inability to return can negatively impact quality of life. The importance of these functional outcomes has prompted reviews on return to sport and work following surgical procedures such as anterior cruciate ligament reconstruction4,15. The data on return to work and sport following HTO, however, are currently evolving and possibly underreported. Thus, the purposes of this study were to (1) examine timelines for return to sport and work following HTO and (2) examine whether patients return to sport and work at levels similar to preoperative levels.
Materials and Methods
A systematic search strategy previously described by the authors was employed16,17. Two reviewers searched 3 online databases (Embase, MEDLINE, and PubMed) for literature related to return to work or sport following HTO. The search was conducted in October 2015 and retrieved articles from database inception to the search date. The research question and inclusion and exclusion criteria were established a priori. Inclusion criteria were (1) all levels of evidence, (2) male and female patients of all ages, (3) studies published in English, (4) human studies, (5) studies reporting clinical or radiographic outcomes, (6) studies reporting postoperative return to work or sport rates and/or timelines, and (7) all athletic ability levels. Exclusion criteria were (1) nonoperative studies (conservative treatment, technique articles without outcomes, etc.), (2) patients receiving HTO in conjunction with other major surgical procedures, and (3) studies in which the outcomes for exactly the same patients were reported again in a later article.
Four studies meeting the inclusion and exclusion criteria were excluded from the final analysis. Three of those studies used external fixation postoperatively and reported return-to-sport timelines. Since external fixation is an inherent, albeit temporary, barrier to full return to sport, those studies were excluded. Studies using external fixation were, however, included if they examined return to work. The other excluded study examined a population with Kashin-Beck disease, which is endemic to southwestern China. That population is quite distinct from the patient population represented in most HTO literature, and it would not have been comparable with the remainder of included studies.
The key terms used in the search were “knee,” “tibia,” “closing wedge,” “correction accuracy,” “high tibial osteotomy,” “knee osteotomy,” “opening wedge,” “valgus osteotomy knee,” and “corrective osteotomy knee.” The search strategy is outlined in the Appendix.
Two reviewers screened the titles, abstracts, and full text of retrieved studies independently. Disagreements at the title and abstract stages were resolved by automatic inclusion to ensure thoroughness; discrepancies at the full-text stage were resolved by consensus between the reviewers. If a consensus could not be reached, a third, more senior reviewer helped to resolve the discrepancy. Reference lists of included studies were scanned for any additional articles that might have been missed. The Appendix lists the included studies.
Quality Assessment of Included Studies
Study quality was evaluated using the MINORS (Methodological Index for Non-Randomized Studies) criteria18. MINORS is a validated scoring tool for nonrandomized studies (case reports, case series, cohort studies, etc.). Each of the 12 items in the MINORS criteria is given a score of 0, 1, or 2, with maximum scores of 16 for noncomparative studies and 24 for comparative studies.
Data were abstracted in duplicate by 2 reviewers from the included articles and recorded in a spreadsheet that had been designed a priori. Demographic information included author, year of publication, sample size, study design, level of evidence, patient demographics (sex, age, surgical indication, etc.), and details of the procedure performed. In addition, any outcome information, including further surgery and complications, was documented.
Inter-reviewer agreement for article screening was evaluated with use of the kappa (κ) value. Agreement was categorized a priori, with κ > 0.60 indicating substantial agreement; 0.21 ≤ κ ≤ 0.60, moderate agreement; and κ < 0.21, slight agreement19. The intraclass correlation coefficient (ICC) was used to evaluate inter-reviewer agreement for MINORS scores. Descriptive statistics, such as means, ranges, and measures of variance (e.g., standard deviations and 95% confidence intervals [CIs]), are presented where applicable. No meta-analysis was performed, as there was high heterogeneity among the studies and multiple indirect comparisons were performed.
Our initial search yielded 6,197 studies, of which 19 met the inclusion and exclusion criteria for this review (Fig. 1). There was excellent agreement among reviewers at the screening stages involving the title (κ = 0.93; 95% CI, 0.92 to 0.94), abstract (κ = 0.74; 95% CI, 0.70 to 0.79), and full text (κ = 0.89; 95% CI, 0.79 to 0.99). The 19 included studies were all published between 1999 and 2016 and consisted of 13 case series, 4 case reports, 1 retrospective comparative study, and 1 randomized controlled trial (Table I). A total of 1,189 patients and 1,224 knees were treated with HTO and followed for a mean of 65.4 months (range, 8 to 253 months). The mean age of the combined patient population in 17 of the 19 studies was 46.2 years (range, 16 to 80 years), with 1 of the remaining studies reporting a median age of 40 years and the final study not reporting age. A total of 192 (16.1%) of the patients were lost to follow-up or death, and 31 (2.6%) were excluded from the present analysis post hoc (because of contralateral disease in 30 patients and a tibial fracture unrelated to treatment in 1 patient). Of note, 57.4% (128) of all patients lost to or excluded from follow-up came from a single study (conducted by mail survey), which only accounted for 22.5% (267) of the total number of patients. Of the patients available at final follow-up, 614 (63.6%) were reported to be male and 203 (21.0%), female; patient sex was unspecified for the remaining 149 (15.4%) of the patients. Finally, 58 patients (4.9%) were removed from our analysis because they received osteotomies at 2 levels (i.e., simultaneous osteotomies of the distal aspect of the femur and the proximal aspect of the tibia). Thus, our analysis consisted of 908 patients and 940 knees.
Seventeen of the included studies represented Level-IV evidence, one study represented Level-III evidence, and one represented Level-II evidence (Table I). There was high agreement among the quality assessment scores based on the MINORS criteria (ICC = 0.91; 95% CI, 0.88 to 0.93). The included studies had a mean MINORS score (and standard deviation) of 9.8 ± 2.9, which indicates a relatively poor average quality of evidence (Table I).
Indications and Operative Details
The HTO was performed for knee OA in 15 of the 19 studies, for osteochondritis dissecans or varus malalignment in 2, for ankle OA in 1, and for growth arrest of the proximal tibial physis in 1. Thirteen studies used an opening-wedge technique, 2 used a closing-wedge technique, 3 employed both techniques (on different patients), and 1 used a hemicallotasis technique. Overall, 605 patients (636 knees) received opening-wedge HTO, 238 patients (239 knees) received closing-wedge HTO, and 70 patients (70 knees) received hemicallotasis. One study included both opening and closing-wedge procedures but did not specify how many patients were in each group. Among 15 studies, correction angles ranged from 2° to 15°.
Return to Sport
Only 1 study reported the criteria used to determine when patients should return to sport (“osteotomy has radiologically healed completely”), although it was unspecified when this occurred or who determined complete healing (radiologist, surgeon, etc.). Of 250 patients in 11 studies, 218 (87.2%) returned to sport postoperatively. Of 37 patients in 6 studies, 89% returned to sport within 1 year, and all returned by 2 years (Fig. 2). Of 378 patients in 13 studies, 297 (78.6%) returned to sport at an equal or greater level. A variety of methods were used to determine the preoperative level of sport activity, including patient baseline information, original questionnaires developed by the authors, and standardized tools (Table II).
Of 173 patients in 9 studies treated with opening-wedge HTO, 157 (90.8%) returned to sport postoperatively. Of 216 patients in 10 studies on opening-wedge HTO, 184 (85.2%) returned to an equal or greater level of sport postoperatively. In a single study that examined return-to-sport rates of 23 patients receiving closing-wedge HTOs, all 23 (100%) returned to sport postoperatively, with 22 (96%) returning at an equal or greater level.
Of 13 patients in 4 studies who were identified as competitive/professional athletes, 7 (54%) returned to elite-level competition and 6 did not. It was not specified whether those not returning to competition participated in other athletic activities. Three of the athletes who did not return to competition cited the operation as the reason for their lack of return; no reason was specified for the remaining 3.
Return to Work
None of the studies provided information about the criterion used to determine when patients could return to work. Of 367 patients in 5 studies, 310 (84.5%) returned to work postoperatively. Of 322 patients in 5 studies, 211 (65.5%) returned to an equal or greater level of physical work. Two of these 5 studies involved homogeneous populations with well-defined duties (agricultural workers and military service members), while the other 3 used the REFA Association classification (Table III).
Preoperative and postoperative work levels were reported for 296 patients in 4 studies who were treated with opening-wedge HTO. Of these, 242 (81.8%) returned to work postoperatively, with 186 (62.8%) returning at an equal or greater level of physical demand. In 1 study of 26 patients receiving closing-wedge HTOs, 25 (96%) returned to work postoperatively, all of whom returned at an equal or greater level.
Specific timelines for return to work were reported for 92 patients in 5 studies. A mean time of 3.5 months away from work was reported in 2 opening-wedge HTO studies with 83 patients, and a median time of 2.9 months was reported in another opening-wedge HTO study with 32 patients. Two studies found that patients with more physically demanding jobs took longer to return to work, but the difference did not reach significance (p > 0.05). One closing-wedge HTO study with 26 patients examined a homogenous group of agricultural workers who had spent 12 to 14 hours per day engaged in fieldwork preoperatively. That study indicated a range of 8 to 12 months away from work. Another closing-wedge HTO study with 51 patients indicated a mean of 3.1 months away from work. Across 3 studies, 92.1% of patients returned to work within 1 year.
Complications and Progression to Total Knee Arthroplasty
A total of 59 complications occurred in 53 of 1,017 patients (complication rate, 5.8%) (Table IV). Complication rates were 8.5% (55 complications in 49 patients) for opening-wedge HTO and 2.1% (4 complications in 4 patients) for closing-wedge HTO. The complication rate was not reported in the 1 hemicallotasis study. The most common complications included infection (n = 12) and hardware failure (n = 8). No complications were believed to be related to an early return to weight-bearing, work, or sport. We did not report hardware removal as a complication because this is frequently a planned re-operation in the absence of symptoms.
Across 18 studies consisting of 881 patients (913 knees), 62 patients treated with HTO (7.0%) progressed to TKA in a mean time of 6.7 years (range, 0.8 to 15 years). Specifically, 3.5% of patients treated with opening-wedge HTO (20 of 573 patients) progressed to TKA at a mean of 4.8 years (range, 1.2 to 14 years), whereas 7.1% (17) of 238 patients treated with closing-wedge HTO progressed to TKA at a mean of 9.6 years (range, 2 to 15 years). Of those treated by hemicallotasis, 35.7% (25) of 70 progressed to TKA at a mean of 7 years (range, 0.8 to 10 years). In 1 study, TKA at the time of follow-up was used as an exclusion criterion and thus the number of patients with progression to TKA was not reported.
The key finding from this review is the high propensity for patients undergoing HTO to return to work and sport. Averaged across all types of HTO, more than four-fifths of patients returned to work or sport, with the majority returning by 1 year postoperatively. More physically demanding jobs required a longer time away from work. Approximately four-fifths of patients returned to sport at a level equal to or greater than their preoperative level. Approximately two-thirds of patients returned to work at a level of physical demand equal to or greater than their preoperative level, although this may be an underestimate. The vast majority (96%) of patients who returned to work at lower levels were from a single study conducted in a military population. The authors of that study discuss the stringent, standardized physical requirements of this occupation20. Thus, this population is unlikely to represent the general population. Among non-military patients included in this review, nearly all (97.8%) returned to work at an equal or greater level.
The complication rate in this review (5.8%) falls below previously reported rates (8% to 35%)21-23. Seven percent of this young, high-demand population progressed to TKA, after an average time of >6 years postoperatively. Given the mean follow-up period of just over 5 years, this is similar to 5-year survival rates of HTO previously reported in the literature (90% to 99%)24-28. Patients undergoing closing-wedge HTO were more than twice as likely to progress to TKA, although the average time to TKA was also twice as long in closing-wedge HTO. Thus, this may be a result of different follow-up periods rather than an inherent difference between the techniques. Alternatively, given that closing-wedge HTO makes subsequent TKA more difficult, surgeons may be delaying TKA longer in these patients.
Return-to-work and return-to-sport rates after TKA in the literature have been variable, ranging from 25% to 95%29-31. For both work and sport, low-impact activities were prescribed and most patients returned to lower levels of physical demand30,31. Thus, while the true rates of return to work and sport following TKA are unclear, HTO appears to be a safe and effective option to delay TKA while allowing patients to return to work and sport at levels similar to their preoperative levels.
This study has many strengths, including the extensive search strategy intended to capture all related literature. In addition, broad inclusion criteria, including no age, sex, or date restrictions, ensured thoroughness. Duplicate screening of all articles limited reviewer bias. The number of patients captured in this review is quite substantial and allowed extrapolation of subgroup data where available to provide an unbiased picture of the results. Furthermore, the study provides data on return to sport and work following HTO that include recreational and professional athletes. Finally, the study demonstrates that joint preservation by HTO is safe and generally delays the need for TKA.
The study also has a number of limitations. Primarily, analysis was limited by the low quality of evidence within the current literature on this topic. In addition, there was great heterogeneity in the scales used to measure sport and activity, which makes it difficult to compare the various studies and their outcomes. Some studies used both opening and closing-wedge HTO but did not report data separately for the 2 groups. Finally, approximately one-sixth of patients were lost to follow-up or death, resulting in a risk of biased and inaccurate results if patients who dropped out did so because of worse outcomes. It should be noted, however, that the majority of patients lost to follow-up came from a single, long-term study conducted by mail survey.
Future studies should focus on producing more robust and higher-quality evidence for the use of HTO in young, active, and employed patients. Longer follow-up, prospective cohort studies, and randomized comparative studies would improve our understanding of when to recommend HTO. Prospective studies examining more precise return-to-work and return-to-sport timelines would help clinicians to accurately inform patients and manage their expectations.
A table showing the search strategy and a list of references for the included studies are available with the online version of this article as a data supplement at jbjs.org.
Investigation performed at McMaster University, Hamilton, Ontario, Canada
Disclosure: The authors stated that no external funding was received for this work. On the Disclosure of Potential Conflicts of Interest forms, which are provided with the online version of the article, one or more of the authors checked “yes” to indicate that the author had a relevant financial relationship in the biomedical arena outside the submitted work.
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