Role of joint distraction in osteoarthritis of the knee: Basic science, principles and outcomes.

The burden of knee osteoarthritis (OA) is increasing worldwide. Advanced tibiofemoral joint OA in young patients is particularly a problem with inferior results seen with total knee arthroplasty in this patient population. Knee joint distraction (KJD) has been evaluated recently as a joint preserving procedure for young patients with advanced tibiofemoral osteoarthritis, to delay the need for a primary total knee arthroplasty (TKA). This will decrease the risk for revision TKA later in life. KJD temporarily unloads the knee joint and keeps the tibia and femur separated over a course of 6 weeks. Outcomes of KJD appear promising. Through this article, the authors hope to share from their collective experience as well as the available literature on the basic science, principles of surgery and outcomes of KJD.

Knee Joint Distraction Compared with High Tibial Osteotomy and Total Knee Arthroplasty: Two-Year Clinical, Radiographic, and Biochemical Marker Outcomes of Two Randomized Controlled Trials.

OBJECTIVE: Both, knee joint distraction (KJD) and high tibial osteotomy (HTO) are joint-preserving surgeries that postpone total knee arthroplasty (TKA) in younger osteoarthritis (OA) patients. Here we evaluate the 2-year follow-up of KJD versus TKA and KJD versus HTO in 2 noninferiority studies. DESIGN: Knee OA patients indicated for TKA were randomized to KJD (n = 20; KJDTKA) or TKA (n = 40). Medial compartmental knee OA patients considered for HTO were randomized to KJD (n = 23; KJDHTO) or HTO (n = 46). Patient-reported outcome measures were assessed over 2 years of follow-up. The radiographic joint space width (JSW) was measured yearly. In the KJD groups, serum-PIIANP and urinary-CTXII levels were measured as collagen type-II synthesis and breakdown markers. It was hypothesized that there was no clinically important difference in the primary outcome, the total WOMAC, when comparing KJD with HTO and with TKA. RESULTS: Both trials were completed, with 114 patients (19 KJDTKA; 34 TKA; 20 KJDHTO; 41 HTO) available for 2-year analyses. At 2 years, the total WOMAC score (KJDTKA: +30.4 [95% CI 23.0-37.9] points; TKA: +42.4 [95% CI 38.1-46.8]; KJDHTO: +21.6 [95% CI 13.8-29.4]; HTO: +29.2 [95% CI 23.6-34.8]; all: P < 0.05) and radiographic minimum JSW (KJDTKA: +0.9 [95% CI 0.2-1.6] mm; KJDHTO: +0.9 [95% CI 0.5-1.4]; HTO: +0.6 [95% CI 0.3-0.9]; all: P < 0.05) were still increased for all groups. The net collagen type-II synthesis 2 years after KJD was increased (P < 0.05). Half of KJD patients experienced pin tract infections, successfully treated with oral antibiotics. CONCLUSIONS: Sustained improvement of clinical benefit and (hyaline) cartilage thickness increase after KJD is demonstrated. KJD was clinically noninferior to HTO and TKA in the primary outcome.

Knee joint distraction in regular care for treatment of knee osteoarthritis: A comparison with clinical trial data.

OBJECTIVES: Knee joint distraction (KJD) has been evaluated as a joint-preserving treatment to postpone total knee arthroplasty in knee osteoarthritis patients in three clinical trials. Since 2014 the treatment is used in regular care in some hospitals, which might lead to a deviation from the original indication and decreased treatment outcome. In this study, baseline characteristics, complications and clinical benefit are compared between patients treated in regular care and in clinical trials. METHODS: In our hospital, 84 patients were treated in regular care for 6 weeks with KJD. Surgical details, complications, and range of motion were assessed from patient hospital charts. Patient-reported outcome measures were evaluated in regular care before and one year after treatment. Trial patients (n = 62) were treated and followed as described in literature. RESULTS: Patient characteristics were not significantly different between groups, except for distraction duration (regular care 45.3±4.3; clinical trials 48.1±8.1 days; p = 0.019). Pin tract infections were the most occurring complication (70% regular care; 66% clinical trials), but there was no significant difference in treatment complications between groups (p>0.1). The range of motion was recovered within a year after treatment for both groups. WOMAC questionnaires showed statistically and clinically significant improvement for both groups (both p<0.001 and >15 points in all subscales) and no significant differences between groups (all differences p>0.05). After one year, 70% of patients were responders (regular care 61%, trial 75%; p = 0.120). Neither regular care compared to clinical trial, nor any other characteristic could predict clinical response. CONCLUSIONS: KJD as joint-preserving treatment in clinical practice, to postpone arthroplasty for end-stage knee osteoarthritis patient below the age of 65, results in an outcome similar to that thus far demonstrated in clinical trials. Longer follow-up in regular care is needed to test whether also long-term results remain beneficial and comparable to trial data.

Prognostic Factors for Return to Sport After High Tibial Osteotomy: A Directed Acyclic Graph Approach.

BACKGROUND: High tibial osteotomy (HTO) is increasingly used in young and physically active patients with knee osteoarthritis. These patients have high expectations, including return to sport (RTS). By retaining native knee structures, a return to highly knee-demanding activities seems possible. However, evidence on patient-related outcomes, including RTS, is sparse. Also, time to RTS has never been described. Furthermore, prognostic factors for RTS after HTO have never been investigated. These data may further justify HTO as a surgical alternative to knee arthroplasty. PURPOSE: To investigate the extent and timing of RTS after HTO in the largest cohort investigated for RTS to date and to identify prognostic factors for successful RTS. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Consecutive patients with HTO, operated on between 2012 and 2015, received a questionnaire. First, pre- and postoperative sports participation questions were asked. Also, time to RTS, sports level and frequency, impact level, the presymptomatic and postoperative Tegner activity score (1-10; higher is more active), and the postoperative Lysholm score (0-100; higher is better) were collected. Finally, prognostic factors for RTS were analyzed using a logistic regression model. Covariates were selected based on univariate analysis and a directed acyclic graph. RESULTS: We included 340 eligible patients of whom 294 sufficiently completed the questionnaire. The mean follow-up was 3.7 years (± 1.0 years). Out of 256 patients participating in sports preoperatively, 210 patients (82%) returned to sport postoperatively, of whom 158 (75%) returned within 6 months. We observed a shift to participation in lower-impact activities, although 44% of reported sports activities at final follow-up were intermediate- or high-impact sports. The median Tegner score decreased from 5.0 (interquartile range [IQR], 4.0-6.0) presymptomatically to 4.0 (IQR, 3.0-4.0) at follow-up (P < .001). The mean Lysholm score at follow-up was 68 (SD, ± 22). No significant differences were found between patients with varus or valgus osteoarthritis. The strongest prognostic factor for RTS was continued sports participation in the year before surgery (odds ratio, 2.81; 95% CI, 1.37-5.76). CONCLUSION: More than 8 of 10 patients returned to sport after HTO. Continued preoperative sports participation was associated with a successful RTS. Future studies need to identify additional prognostic factors.

Response rate and costs for automated patient-reported outcomes collection alone compared to combined automated and manual collection.

BACKGROUND: The response rate on patient-reported outcome measurements (PROMs) necessary to adequately evaluate a treatment and improve patient care is unknown. Hospitals generally aim for the highest possible response rate without insight into the increase in costs involved. This study aimed to investigate which PROMs response rate is achievable in relation to the costs in an orthopaedic practice. METHODS: In an observational study, patients planned for orthopaedic surgery were asked to participate per surgical procedure (5769 surgical procedures at 5300 patients). Patient-reported outcomes (PROs) collection with a digital online automated PROMs collection system (minimal effort) was compared to a combined automated system and manual collection (maximal effort). Response rate was calculated preoperative and at two postoperative time points separately, and on all three time points together. Costs were calculated for the study period, per year and per surgical procedure. Calculations were executed for all surgical procedures and for three subgroups: knee arthroplasty, hip arthroplasty and anterior cruciate ligament reconstruction (ACLR). RESULTS: Using maximal effort the response rate increased for all surgical procedures compared to minimal effort; the preoperative response rate from 86% to 100% and the postoperative response rates from 55% to 83% (3 or 6 months) and 53% to 83% (12 months). Concerning the response at all three time points for all surgical procedures, minimal effort resulted in 44% response rate and increased to 76% with maximal effort. Lowest postoperative response rates were found in the ACLR group for both maximal and minimal effort. A costs difference of €5.55-€5.98 per surgical procedure between maximal and minimal effort was found. CONCLUSIONS: A two times higher PROMs response rate for patients responding at all three time points (44% versus 76%) is achievable with maximal effort compared to the use of an automated PROMs collection system only. Manual collection adds a cost of €5.5-€6 per surgical procedure to automated PROMs collection alone. It is debatable if these additional costs are justifiable from a value-based health care perspective as the response rate for adequate evaluation of a treatment is still unknown.

Eight respectively nine out of ten patients return to sport and work after distal femoral osteotomy.

PURPOSE: Distal femoral osteotomy (DFO) is a well-accepted procedure for the treatment of femoral deformities and associated symptoms including osteoarthritis, especially in younger and physically active patients in whom knee arthroplasty is undesirable. Still, there is an apparent need for evidence on relevant patient outcomes, including return to sport (RTS) and work (RTW), to further justify the use of knee osteotomy instead of surgical alternatives. Therefore, the purpose of the present study was to investigate the extent and timing of patients' RTS and RTW after DFO. METHODS: This monocentre, retrospective cohort study included consecutive DFO patients, operated between 2012 and 2015. Out of 126 eligible patients (18-70 years, 63% female), all patients responded, and 100 patients completed the questionnaire. Median follow-up was 3.4 years (range 1.5-5.2). The predominant indication for surgery was symptomatic unicompartmental osteoarthritis and valgus or varus leg alignment caused by a femoral deformity. The primary outcome measure was the percentage of RTS and RTW. Secondary outcome measures included time to RTS/RTW, sports level and frequency, the median pre-symptomatic and postoperative Tegner activity score (1-10, higher is more active) and the postoperative Lysholm score (0-100, higher is better). RESULTS: Out of 84 patients participating in sports preoperatively, 65 patients (77%) returned to sport postoperatively. Forty-six patients (71%) returned to sports within 6 months. Postoperative participation in high-impact sports was possible though less frequent compared to preoperative participation. Out of 80 patients working preoperatively, 73 (91%) returned to work postoperatively, of whom 59 patients (77%) returned within 6 months. The median pre-symptomatic Tegner activity score [4.0 (range 0-10)] was significantly higher (p < 0.01) than the reported Tegner score at follow-up [3.0 (range 0-10)]. The mean Lysholm score at follow-up was 68 (± 22). No significant differences were found between the osteoarthritis- and non-osteoarthritis group. CONCLUSION: Eight out of ten patients return to sport and nine out of ten patients return to work after DFO. These are clinically relevant findings, because they further justify DFO as a surgical alternative to KA in young, active knee OA patients who wish to return to high activity levels. LEVEL OF EVIDENCE: Retrospective cohort study, Level III.

Medial open wedge high tibial osteotomy: can delayed or nonunion be predicted?

BACKGROUND: The opening wedge approach to high tibial osteotomy (HTO) is perceived to have some advantages relative to the closing wedge approach but it may be associated with delayed and nonunions. Because nonunions evolve over months, it would be advantageous to be able to identify risk factors for and early predictors of nonunion after medial opening wedge HTO. QUESTIONS/PURPOSES: We sought to determine whether (1) preoperatively identifiable patient factors, including tobacco use, body mass index > 30 kg/m(2), and degree of correction, are associated with nonunion, and (2) a modified Radiographic Union Score for Tibial Fractures (RUST) score, taken at 6 weeks and 3 months, would be predictive for delayed or nonunion after medial opening wedge HTO. METHODS: The medical records and radiographs of 185 patients, 21 bilateral cases, treated with a medial open wedge HTO using the TomoFix(®) device were retrospectively evaluated. For all patients, demographic data regarding risk factors were collected from their records. Diagnosis for delayed or nonunion was already done earlier for standard medical care by the orthopaedic surgeon based on clinical and radiographic grounds. For the retrospective radiographic evaluation, a modified RUST score was used in which each tibial cortex is scored by one observer. Logistic regression analysis was used to identify preoperative and postoperative predictive factors for developing delayed or nonunion. In the series, a total of 19 patients (9.2%) developed clinically delayed/nonunion of whom 10 patients (4.9%) developed a nonunion. RESULTS: Smoking was identified as a risk factor for developing delayed/nonunion (19% for smokers versus 5.4% for nonsmokers; p = 0.005; odds ratio, 4.1; 95% confidence interval, 1.5-10.7). By contrast, body mass index, lateral cortical hinge fracture, age, infection, and degree of correction were not risk factors. Patients with delayed/nonunion had lower RUST scores at all time points when a radiograph was taken compared with the total study group. CONCLUSIONS: The RUST score at 6 weeks and 3 months after surgery and the use of tobacco were identified as predictive factors for development of delayed union and nonunion after open wedge HTO. Based on these results, we now actively try to stop patients from smoking and these data are helpful in doing that. The RUST score may be of use to identify which patients are at risk for developing a delayed union so that interventions may be offered earlier in the course of care. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.