Deterioration of patellofemoral cartilage status after medial open-wedge high tibial osteotomy

Difference in the anterior displacement of the tibial tuberosity relative to the proximal tibial fragment between opening wedge and closed wedge high tibial osteotomies

INTRODUCTION

This study aimed to investigate the anterior-posterior (AP) displacement of the tibial tuberosity (TT) and to assess the difference between closed wedge and opening wedge high tibial osteotomies (OWHTO and CWHTO).

METHODS

One hundred consecutive knees with osteoarthritis that underwent OWHTO (50 knees) or CWHTO (50 knees) were investigated retrospectively. The femorotibial angle (FTA) was measured on AP radiographs of the knee. AP displacement of the TT, posterior tibial slope (PTS), the modified Blackburne-Peel index (mBPI), and the modified Caton-Deschamps index (mCDI) were measured on lateral radiographs of the knee.

RESULTS

Patients had a mean correction angle of 12.58 ± 2.84° and 18.98 ± 5.14° (P < 0.001), with a mean AP displacement of TT of 0.84 ± 2.66 mm and 7.78 ± 3.41 mm (P < 0.001) in OWHTO and CWHTO, respectively. The AP displacement of the TT per correction of 1° was significantly greater in CWHTO than in OWHTO (P < 0.001). A significant correlation was found between the correction angle and AP displacement of the TT in CWHTO (r = -0.523, P < 0.001), but not in OWHTO. The change of PTS per correction of 1° was significantly greater in OWHTO than in CWHTO (P < 0.001). The changes of mBPI and mCDI per correction of 1° were significantly greater in CWHTO than in OWHTO (P < 0.001 and P < 0.001, respectively).

CONCLUSIONS

There was greater anterior displacement of the TT in CWHTO than in OWHTO, which was correlated with the correction angle. The results suggested that CWHTO would be better than OWHTO when a concomitant anteriorization of TT is required.

Changes in Patellar Height and Tibial Posterior Slope after Biplanar High Tibial Osteotomy with Computer-Designed Personalized Surgical Guides: A Retrospective Study

OBJECTIVE

Medial opening-wedge high tibial osteotomy (MOWHTO) is a surgical procedure to treat medial compartment osteoarthritis in the knee with varus deformity. However, factors such as patellar height (PH) and the sagittal plane's posterior tibial slope angle (PTSA) are potentially overlooked. This study investigated the impact of alignment correction angle guided by computer-designed personalized surgical guide plate (PSGP) in MOWHTO on PH and PTSA, offering insights for enhancing surgical techniques.

METHODS

This retrospective study included patients who underwent 3D-printed PSGP-assisted MOWHTO at our institution from March to September 2022. The paired t-tests assessed differences in all preoperative and postoperative measurement parameters. Multivariate linear regression analysis examined correlations between PTSA, CDI (Caton-Deschamps Index), and the alignment correction magnitude. Receiver operating characteristic (ROC) curve analysis determined the threshold of the correction angle, calculating sensitivity, specificity, and area under the curve.

RESULTS

A total of 107 patients were included in our study. The CDI changed from a preoperative mean of 0.97 ± 0.13 (range 0.70-1.34) to a postoperative mean of 0.82 ± 0.13 (range 0.55-1.20). PTSA changed from a preoperative mean of 8.54 ± 2.67 (range 2.19-17.55) to a postoperative mean of 10.54 ± 3.05 (range 4.48-18.05). The t-test revealed statistically significant changes in both values (p < 0.05). A significant alteration in patellar height occurred when the correction angle exceeded 9.39°. Moreover, this paper illustrates a negative correlation between CDI change and the correction angle and preoperative PTSA. Holding other factors constant, each 1-degree increase in the correction angle led to a 0.017 decrease in postoperative CDI, and each 1-degree increase in preoperative PTSA resulted in a 0.008 decrease in postoperative CDI. PTSA change was positively correlated only with the correction angle; for each 1-degree increase in the opening angle, postoperative PTS increased by 0.188, with other factors constant.

CONCLUSION

This study highlights the effectiveness and precision of PSGP-assisted MOWHTO, focusing on the impact of alignment correction on PH and PTSA. These findings support the optimization of PSGP technology, which offers simpler, faster, and safer surgeries with less radiation and bleeding than traditional methods. However, PSGP's one-time use design and the learning curve required for its application are limitations, suggesting areas for further research.

Femoral trochlear groove cartilage damage after open-wedge high tibial osteotomy is associated with the change in patellar height relative to the femoral condyle

BACKGROUND

Medial open-wedge high tibial osteotomy (OWHTO) is performed for isolated medial compartment osteoarthritis or osteonecrosis of the knee and correction of varus deformity of the full lower extremity. OWHTO may induce sagittal parameter changes, including these in the tibial posterior slope (TPS), patellar height (PH), and patellofemoral joint problems. This study aimed to identify radiographic parameters associated with patellofemoral cartilage damage after OWHTO.

HYPOTHESIS

The patellofemoral joint cartilage worsens after OWHTO and is adversely affected by PH changes.

PATIENTS AND METHODS

Twenty patients (25 knees) who underwent primary OWHTO and subsequent implant removal surgery, including second-look arthroscopy for evaluation of the patellofemoral cartilage condition were enrolled. The patients were received 12 to 35 months of postoperative follow-up, and categorized into two groups according to whether patellofemoral cartilage damage worsened. TPS and PH parameters, including the Insall-Salvati, Blackburne-Peel, Caton-Deschamps, and modified Blumensaat (MBI) indices, were measured on lateral knee radiographs. The hip-knee-ankle and medial proximal tibial angles were measured using an anteroposterior radiograph of the full lower extremity. The extent of change from preoperative to postoperative (Δ) was calculated for all indices.

RESULTS

Eleven knees (44%) had worsening cartilage conditions in the femoral trochlear groove, with>1-degree of deterioration in the International Cartilage Repair Society grade. The radiographic measure for predicting patellofemoral cartilage deterioration was ΔMBI (95% confidence interval [CI]: 3.53×10-14-0.812, p=0.047). PF cartilage damage tended to progress in ΔMBI<-0.145. The postoperative TPS and HKAA in patients with deterioration in patellofemoral cartilage damage was greater than that in patients without deterioration in patellofemoral cartilage damage (p=0.037 and 0.038, respectively).

DISCUSSION

The patellofemoral cartilage damage tends to progress after OWHTO. ΔMBI is a factor for predicting worsening patellofemoral cartilage condition. However, attention should be paid to the excessive posterior slope as high TPS and valgus alignment as valgus HKAA because intraoperative control of MBI is impossible.

LEVEL OF EVIDENCE

IV, retrospective study.

High tibial osteotomy combined with cartilage restoration: A systematic review of clinical outcomes and prognostic factors

Background

Focal chondral defects are often treated with cartilage restoration procedures. Malalignment often accompanies chondral defects. High tibial osteotomy (HTO), classically utilized to treat uni-compartmental knee osteoarthritis, corrects malalignment. HTO combined with cartilage restoration procedures can treat uni-compartmental osteoarthritis and focal chondral defects.

Purpose

To assess outcomes of combined HTO and cartilage restoration procedures and review prognostic factors that may assist in preoperative planning and patient counseling.

Study design

Systematic Review of published literature.

Methods

A systematic review of PubMed and Scopus was performed following PRISMA guidelines. Thirty-four papers were included in qualitative considerations.

Results

Thirty-four papers that reported the combined outcome of HTO and cartilage repair were included. Twenty of the 34 included papers reported prognostic factors that affected the success or failure of combined HTO and cartilage repair surgery for focal articular defect and uni-compartmental knee osteoarthritis. Cartilage repair techniques that were combined with HTO and included in this review are bone marrow stimulation, allograft transplantation, osteochondral autograft transplantation, autologous chondrocyte implantation, and mesenchymal stem cell implantation.

Conclusions

HTO with adjunctive cartilage repair procedures improve clinical outcome scores and restore alignment in patients with medial compartment osteoarthritis and isolated focal chondral defects. HTO with adjunctive cartilage procedures produces optimal results in younger, non-obese patients with focal chondral defects and varus malalignment, without significant lateral compartment and patellofemoral involvement.

Patellofemoral Osteoarthritis Progression After Open-Wedge High Tibial Osteotomy Does Not Affect the Clinical Outcomes or Survivorship at Minimum 7 Years' Follow-Up

PURPOSE

To evaluate the clinical and radiologic outcomes of open-wedge high tibial osteotomy (OWHTO) with respect to the patellofemoral joint and to assess the effects of patellofemoral osteoarthritis (OA) progression after OWHTO on clinical outcomes at minimum 7 years' follow-up.

METHODS

We retrospectively reviewed 95 knees that underwent OWHTO and at least 7 years of follow-up. Clinical parameters including anterior knee pain, Japanese Orthopedic Association score, Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Score, Hospital for Special Surgery patella score, and Knee Injury and Osteoarthritis Outcome Score-patellofemoral subscale were evaluated. Radiologic outcomes were evaluated preoperatively and at final follow-up. Patellofemoral OA progressions were evaluated using Kellgren-Lawrence grade, and we divided the patients into 2 groups (progression group and non-progression group) to evaluate the effect of patellofemoral OA progression after OWHTO on long-term clinical outcomes.

RESULTS

The mean follow-up period was 10.8 ± 2.6 years (range: 7.6-17.3 years). The mean Japanese Orthopedic Association score significantly improved (from 64.4 ± 11.6 to 90.9 ± 9.3, P < .001), and the mean Oxford Knee Score at final follow-up was 40.4 ± 8.3. Due to medial OA progression, 5 cases were converted to total knee arthroplasty, and the survival rate was 94.7% at 10.8 years of follow-up. Radiologically, patellofemoral OA progression was observed at final follow-up in 48 knees (50.5%). However, there were no significant differences in all clinical outcomes at final follow-up between the progression and non-progression groups.

CONCLUSIONS

Patellofemoral OA progression may progress over long-term follow-up after OWHTO. Related symptoms are minimal and this does not affect the clinical outcomes or survivorships at minimum 7 years follow-up.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Cartilage Degeneration of the Lateral Compartment of the Knee at Second-Look Arthroscopy Is Associated With Deterioration of 10-Year Clinical Outcomes After Opening-Wedge High Tibial Osteotomy

PURPOSE

To identify the arthroscopic findings associated with deterioration of 10-year clinical outcomes after opening-wedge high tibial osteotomy (OWHTO) in patients with knee osteoarthritis.

METHODS

A total of 114 consecutive knees of 91 patients with knee osteoarthritis who underwent OWHTO between 2007 and 2011 were retrospectively reviewed. Of these patients, those who underwent second-look arthroscopy and were followed up for a minimum of 10 years were enrolled. The Knee Society Score (KSS) and hip-knee-ankle angle were assessed. Cartilage status was graded at the time of osteotomy (first look) and plate removal (second look) according to the International Cartilage Repair Society (ICRS) grading system. The KSS knee subscale score and function subscale score were assessed separately, and on the basis of the changes in each of these scores from 1 to 10 years postoperatively and the minimal clinically important difference (MCID), the patients were divided into 2 groups: deteriorated (deterioration of score ≥ MCID) and non-deteriorated (deterioration of score < MCID).

RESULTS

Sixty-nine knees were included in this study. The mean knee score improved continuously from 48.7 ± 11.3 preoperatively to 86.8 ± 10.3 at 1 year (P < .001), 87.5 ± 9.9 at 5 years (P < .001), and 86.5 ± 10.5 at 10 years (P < .001) postoperatively. The mean function score also improved continuously from 62.5 ± 12.1 preoperatively to 90.7 ± 12.9 at 1 year (P < .001), 91.6 ± 12.1 at 5 years (P < .001), and 88.5 ± 13.1 at 10 years (P < .001) postoperatively. Three knees underwent conversion to total knee arthroplasty within 10 years postoperatively. The deteriorated KSS group showed significantly progressed ICRS grades in the lateral compartment compared with the non-deteriorated KSS group. The ICRS grade in the lateral compartment at second-look arthroscopy was identified as the only significant factor associated with both knee score deterioration (odds ratio, 4.89; P = .03) and function score deterioration (odds ratio, 3.91; P = .03) on multivariable logistic regression analysis.

CONCLUSIONS

The presence of cartilage degeneration of the lateral compartment of the knee at second-look arthroscopy is associated with deterioration of long-term clinical outcomes after OWHTO.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Radiologic simulation of leg length change after double level osteotomy in preoperative surgical planning

BACKGROUND

To evaluate the expected postoperative total leg length change using preoperative radiographs during surgical planning of four different methods of double level osteotomy (DLO).

METHODS

This study included 34 patients (44 knees) who underwent DLO for varus knee osteoarthritis. Surgical planning was performed so that the postoperative weight bearing line ratio was 62.5%. In DLO, lateral closed or medial open wedge distal femoral osteotomy (LCWDFO, MOWDFO) was performed so that the postoperative mechanical lateral distal femoral angle was 85°, and residual deformity was corrected with medial open or lateral closed wedge high tibial osteotomy (MOWHTO, LCWHTO). Pre- and surgical planning X-rays in the one-leg standing position were compared to assess the change in leg length, and the factors affecting it, in the various surgical groups. The proportion of cases in which Δ total leg length was greater than 6 mm (symptomatic change) was investigated.

RESULTS

The mean postoperative total leg length increased significantly with LCWDFO + MOWHTO, MOWDFO + MOWHTO, and MOWDFO + LCWHTO, while it decreased with LCWDFO + LCWHTO. The proportion of cases with a postoperative total leg length change > 6 mm was 72.7%, 2.3%, 100%, and 6.8% in LCWDFO + MOWHTO, LCWDFO + LCWHTO, MOWDFO + MOWHTO, and MOWDFO + LCWHTO, respectively. In addition, the preoperative hip-knee-ankle angle correlated negatively with the postoperative total leg length change in LCWDFO + MOWHTO, MOWDFO + MOWHTO, and MOWDFO + LCWHTO, but not in LCWDFO + LCWHTO.

CONCLUSIONS

MOWDFO + MOWHTO had the largest postoperative leg length change and MOWDFO + LCWHTO had the smallest. Symptomatic leg length change (> 6 mm) should be considered in MOWDFO + MOWHTO and LCWDFO + MOWHTO.

Open wedge high tibial osteotomy does not decrease patellar height relative to femur: A three-dimensional computer model analysis

BACKGROUND

Patellar height, which decreases after open wedge high tibial osteotomy (OWHTO), has conventionally been assessed by tibial references using lateral radiographs of the knee; however, changes in the proximal tibia shape after OWHTO may affect this method. We aimed to evaluate the changes in patellar height position relative to the transepicondylar axis of the femur after OWHTO using in vivo three-dimensional (3D) computer models.

METHODS

Fourteen patients who underwent 3D magnetic resonance imaging (MRI) at 30° and 50° knee flexion before OWHTO and after hardware removal were included. 3D computer models of the knee were created from the MRI scans and superimposed over the images taken in each position using voxel-based registration. For patellar height evaluation, a patellar reference point was established at each flexion angle and the femoral condylar planes (FCP) were set, including the transepicondylar axis. The patellar center angle was defined as the angle between an FCP that included the top of the intercondylar notch and an FCP that included the patellar reference point. The patellar center angle was evaluated at 30° and 50° knee flexion before and after OWHTO.

RESULTS

The patellar center angle at 30° and 50° knee flexion did not significantly decrease after OWHTO, whereas the Caton-Deschamps index and Blackburne-Peel index based on tibia-referenced measurements significantly decreased postoperatively.

CONCLUSION

Patellar height position relative to the femur in the 3D computer model did not decrease after OWHTO, whereas tibia-referenced conventional radiographic measurements significantly decreased. When evaluating patellar height, characteristics of each parameter should be considered.

Can double-level osteotomy prevent patellofemoral osteoarthritis progression compared with open wedge high tibial osteotomy?

PURPOSE

To compare radiographic, clinical, and arthroscopic findings in patellofemoral (PF) osteoarthritis (OA) between open wedge high tibial osteotomy (OWHTO) and double-level osteotomy (DLO) with the same operative indication.

METHODS

After adjustment for patient age, and coronal alignment, 36 knees with OWHTO alone and 36 knees with DLO were compared. Radiographic, clinical, and arthroscopic findings were documented before osteotomy. Arthroscopic findings were observed 1 year after osteotomy, and clinical and radiographic findings were observed 2 years after osteotomy. Patellar height was evaluated using the Insall-Salvati (IS) ratio, Carton-Deschamps (CD) index, and Blackburne-Peel (BP) index. Lateral patellar tilt and patellar shift were measured. A power analysis was performed.

RESULTS

The postoperative CD and BP indices in the OWHTO group were lower than those in the DLO group (p < 0.001 and p = 0.001, respectively). The CD and BP indices in both groups significantly decreased postoperatively (all p < 0.001). Tilting angles in the OWHTO and DLO groups significantly decreased postoperatively (p < 0.001 and p = 0.002, respectively). There were no significant differences in American Knee Society scores, Kujala score, and the Knee Injury and Osteoarthritis Outcome Scores between both groups. The PF OA progression of the trochlear in the OWHTO group was higher than that in the DLO group (p = 0.002), and the PF OA progression of the patellar facet in the DLO group and anterior femoral condyle in both groups on the lateral side were higher than those on the medial side (p = 0.006, 0.032, and 0.041, respectively).

CONCLUSIONS

DLO decreased the rate of low patellar height compared with OWHTO. DLO decreased the rate of PF OA progression in the trochlea compared with OWHTO. There were no significant differences in clinical outcomes in both groups.

LEVEL OF EVIDENCE

Level III, case-control study.

Is proximal tibial tubercle osteotomy superior to distal tibial tubercle osteotomy for medial compartmental osteoarthritis? A meta-analysis

BACKGROUND

Open-wedge high tibial osteotomy (OWHTO) is commonly performed for the treatment of medial compartment knee osteoarthritis (KOA), and is classified into proximal tibial tubercle osteotomy (PTO) and distal tibial tubercle osteotomy (DTO). The PTO osteotomy point is generally located about 3-4 cm below the joint of the proximal tibia, and the osteotomy line points to the upper part of the proximal tibiofibular joint. The DTO osteotomy point is generally located about 0.5-1.0 cm below the tibial tubercle, and the osteotomy line points to the contralateral cortex. However, there is currently no consensus on which surgical technique is superior. The purpose of our study was to investigate which among the two is superior for medial KOA, with respect to knee joint parameters, clinical function, and complications.

METHODS

This study was conducted as per the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The Cochrane Central Library, MEDLINE, Embase, PubMed, CNKI, and WanFang databases were systematically searched for trials comparing PTO and DTO in patients with medial compartment KOA, from inception until March 2022. The meta-analysis was conducted using RevMan 5.2 software. The Cochrane risk-of-bias tool was used to assess methodological quality. Statistical analysis was performed with Stata 12.0. Outcomes of interest included the Insall-Salvati index (ISI), Caton-Deschamps index (CDI), Blackburne-Peel index (BPI), posterior tibial slope (PTS), and the Hospital for Special Surgery (HSS) knee-rating scale.

RESULTS

A total of 15 retrospective studies (910 knees) were included. There were no significant differences in the age or sex of included patients. There was a significant difference in the ISI, CDI, BPI, and PTS between the two groups (all p ≤ 0.05). Further, DTO was associated with a significantly greater number of postoperative complications (p < 0.05) compared to PTO. However, there was no significant difference in the femorotibial angle (FTA), mechanical medial proximal tibial angle (mMPTA), and HSS knee score (all p > 0.05).

CONCLUSIONS

Compared with DTO, PTO is associated with a greater incidence of postoperative patella baja and increased PTS, whereas DTO is associated with more postoperative complications. Nevertheless, both can significantly correct knee varus deformity and improve knee function; their early knee function scores are also similar.

TRIAL REGISTRATION

Prospective Register of Systematic Reviews (PROSPERO) registration number CRD42021284443.

The effects of open wedge high tibial osteotomy for knee osteoarthritis on the patellofemoral joint. A systematic review

BACKGROUND (INCLUDING AIMS OF THE STUDY)

To investigate the impact medial opening wedge high tibial osteotomy (MOWHTO) has on the progression of patellofemoral (PF) OA, patella height, contact pressure within the PF joint and clinical outcomes.

METHODS

A systematic review was conducted in January 2022 according to PRISMA guidelines. The ICRS cartilage grade of the PF joint at the initial MOWHTO surgery and at second look surgery was compared and relative risk of progression of PF OA was calculated. Evaluation of patella height was assessed by Caton-Deschamps index, Blackburne-Peel index or Insall-Salvati index pre and post MOWHTO. Cadaveric studies assessing contact pressures in the PF after MOWHTO were included.

RESULTS

Forty-two studies comparing 2419 patients were included. The mean age was 53.1 years (16-84), 61.3% female. The risk of progression of PF OA was highest in the uniplanar and biplanar MOWHTO with proximal tubercle osteotomy groups (RR = 1.28-1.51) compared to biplanar MOHWTO with distal tubercle osteotomy (RR = 0.96-1.04). Patella height was not affected after biplanar MOWHTO with distal tubercle osteotomy (p < 0.001). Cadaveric studies demonstrate that PF contact pressures increase with more severe corrections (15°) but suggest biplanar MWOHTO and distal tubercle osteotomy induces lower contact pressures within the PF joint than other MOWHTO techniques. Significant over correction is associated with worse clinical outcomes and anterior knee pain.

CONCLUSION

Biplanar MOWHTO and distal tubercle osteotomy has minimal effect on the contact pressures in the PF joint resulting in less severe progression of PF OA and has minimal impact on patella height.

Opening wedge high tibial osteotomy for medial compartment knee osteoarthritis: Planning and improving outcomes: Case series and literature review

Background

Opening wedge high tibial osteotomy (OWHTO) is a safe surgical procedure to treat medial compartmental osteoarthritis caused by a varus deformity. Over-correction of this varus deformity can lead to lateral compartment over-loading. In our study, we planned our correction by using the mechanical axis deviation (MAD).

Purpose

The purpose of this study is to evaluate the clinical and radiological results of OWHTO based on planning using the MAD measurements.

Study Design

Retrospective Case Series.

Methods

14 patients with Kellgren- Lawrence classification (KL) grade 3 or above underwent OWHTO, with plans to have the mechanical axis pass through 5-15 mm lateral to the center of the tibial plateau. Pre-operative and post-operative radiographic measurements were made and compared using the student t-test. SF-36 scores were obtained for clinical performance.

Results

Our patients experienced MAD from 25.9 mm medial to the center of the tibial plateau pre-operatively to 12.7 mm lateral to the center of the plateau post-operatively. The mean change in MAD was 38.7 mm (p < 0.0001). The accuracy of our correction compared to the planned MAD was 98.3%. The mechanical axis angle shifted from 7.35° of varus to 3.5° of valgus (p < 0.0001). All patients had post-operative alignments of 1-6° of valgus, with 11 of out the 14 patients with alignments less than 5° of valgus, preventing over-loading of the lateral compartment.

Conclusion

Using MAD measurements is an accurate planning method for OWHTO that corrects varus deformity without over-loading the lateral compartment, and leads to improved clinical outcomes.

Mid-term results of medial open-wedge high tibial osteotomy based on radiological grading of osteoarthritis

PURPOSE

To evaluate the mid-term results of medial open-wedge high tibial osteotomy (OWHTO) based on Kellgren-Lawrence (KL) grades.

MATERIALS AND METHODS

We retrospectively evaluated clinical and radiographic outcomes of 93 patients (mean age 61.4 years, mean follow-up 64.2 months, 109 consecutive knees) who underwent OWHTO for medial compartment osteoarthritis (OA). KL grade was used to evaluate knee OA (KL-1 22 cases; KL-2, 51 cases; KL-3, 36 cases). The clinical outcomes were assessed using Japanese Orthopaedic Association (JOA) and Lysholm scores. Radiographic outcomes were assessed using pre- and post-operative mechanical axis percentage, femorotibial angle, medial proximal tibial angle, and joint line convergence angle. Hinge fracture frequency and OA progression were also evaluated based on KL grades.

RESULTS

The JOA score improved significantly from 70.3 ± 14.9 to 96.2 ± 4.4, 64.1 ± 12.5 to 95.1 ± 5.1, and 68.6 ± 11.4 to 92.1 ± 6.1 in the KL-1, KL-2, and KL-3 groups, respectively. The JOA score in the KL-3 group was significantly lower than in the other groups. The Lysholm score improved significantly from 62.6 ± 8.8 to 97.7 ± 4.7, 62.1 ± 8.1 to 96.7 ± 4.2, and 59.2 ± 9.2 to 95.8 ± 4.6 in the KL-1, KL-2, and KL-3 groups, respectively. The post-operative Lysholm scores were not significantly different among the groups. There were significant differences in radiographic parameters pre-operatively, but not post-operatively, among the groups. Although there were no significant differences in hinge fracture frequency and OA progression, the KL-3 grade predicted OA progression on multivariate analysis.

CONCLUSIONS

Mid-term results of OWHTO significantly improved. However, clinical score in the KL-3 group was lower than that in the KL-1 and KL-2 groups; radiological OA progression was a risk factor in KL-3.

Potential anatomic risk factors resulting oversized postoperative medial proximal tibial angle after double level osteotomy

BACKGROUND

Double level osteotomy (DLO) has been introduced to prevent increased postoperative joint line obliquity. However, although DLO is planned, knees with postoperative medial proximal tibial angle (MPTA) > 95° in preoperative surgical planning are present. This retrospective study aimed to evaluate risk factors for an MPTA > 95° in preoperative surgical planning for DLO in patients with varus knee osteoarthritis (OA).

METHODS

A total of 168 knees that underwent osteotomies around the knee for varus knee OA were enrolled. The hip-knee-ankle angle (HKA), weight-bearing line (WBL) ratio, mechanical lateral distal femoral angle (mLDFA), joint line convergence angle (JLCA) and mechanical medial proximal tibial angle (mMPTA) were measured on preoperative radiographs. The postoperative WBL ratio was planned to be 62.5%. When the postoperative mMPTA was more than 95° in isolated high tibial osteotomy (HTO), (DLO) was planned so that the postoperative mLDFA was 85°, and residual deformity was corrected by HTO. Knees with postoperative mMPTA ≤ 95° and > 95° were classified into the correctable group and uncorrectable group, respectively.

RESULTS

DLO was required in 101 knees (60.1%). Among them, 41 knees (40.6%) were classified into the uncorrectable group. Binomial logistic regression analysis showed that preoperative JLCA and mMPTA were independent predictors in the uncorrectable group.

CONCLUSIONS

Even with DLO, postoperative mMPTA was more than 95° in approximately 40% of cases. Preoperative increased JLCA and decreased mMPTA were risk factors for a postoperative mMPTA of > 95° after DLO.

Analysis of popliteal artery location for high tibial and distal tuberosity osteotomy using contrast-enhanced computed tomography

Background

Our objective was to evaluate the location of popliteal artery (PA) in osteotomy planes during high tibial osteotomy (HTO) and to determine a safer angle for screw drilling to the tibial tuberosity during distal tuberosity osteotomy (DTO).

Methods

Twenty knees in 20 patients who underwent contrast-enhanced computed tomography for cardiovascular diseases were examined. Osteotomy planes for open-wedge HTO (OWHTO) and hybrid closed-wedge HTO (hybrid CWHTO) were created using three-dimensional bone models. The distance from the posterior cortex of the tibia to the PA (dPC-PA) in the osteotomy planes was measured in the virtual osteotomy planes. The dangerous point (Point D1) was defined as the point 17.5 mm away from PA, setting the working length of the bone saw as 35 mm. The distance between the most medial point of the tibial cortex (Point M) and Point D1 in OWHTO and the most lateral point (Point L) and Point D1 in hybrid CWHTO were examined (dM-D1 and dL-D1, respectively). The location of Point D1 to the osteotomy line (%D1) was expressed as percentage, setting the start and end of the osteotomy line as 0% and 100%, respectively. To determine the safe angle for screw drilling in DTO, the angle between the line tangential to the medial cortex of the tibia and that passing through the center of the tibial tuberosity and PA were measured.

Results

In OWHTO and hybrid CWHTO, the mean dPC-PA was 10.6 mm (6.9–16.5 mm) and 10.2 mm (7.3–15.4 mm), respectively. The mean dM-D1 in OWHTO was 25.9 mm (24.6–27.2 mm) and dL-D1 in hybrid CWHTO was 5.1 mm (2.9–7.4 mm). The mean %D1 was 47.6 ± 3.7% in OWHTO and 9.3 ± 4.1% in hybrid CWHTO, respectively. The minimal angle between the two lines in DTO was 35.2°.

Conclusion

PAs could run within 10 mm from the posterior cortex in the osteotomy planes of HTO. Therefore, proper posterior protection is necessary when cutting posterior cortex. An angle of less than 35° against the medial cortex line would be safe for screw fixation to avoid vascular injury in DTO.

Effect of medial open wedge high tibial osteotomy on progression of patellofemoral osteoarthritis

PURPOSE

This study aimed to investigate the effect of medial open wedge high tibial osteotomy (MOWHTO) on patellofemoral joint osteoarthritis (PF OA) progression and its outcome according to the degree of preexisting PF OA.

MATERIALS AND METHODS

Patients who underwent biplane MOWHTO between January 2006 and December 2018 were retrospectively reviewed. The patients were divided into two groups according to the degree of PF OA: non-PF OA [Kellgren-Lawrence (K-L) grade 0-1] and PF OA (K-L grade 2-3). Propensity score matching was performed between the two groups, and comparative analysis was performed on clinical scores and radiographic parameters and grade.

RESULTS

After propensity score matching, 83 patients were selected for each group. At postoperative follow-up, clinical scores were improved significantly compared with preoperative scores in both groups; however, there were no significant differences between the groups. There were also no significant differences between the two groups in radiographic parameters. The radiographic grade of PF OA indicated a slight progression in osteoarthritis in both groups; however, PF OA tended to progress further in the PF OA group.

CONCLUSIONS

MOWHTO did not result in significant differences in outcomes at postoperative follow-up; however, preexisting PF OA contributed to PF OA progression after MOWHTO.

Risk Factors Affecting Return to Sports and Patient-Reported Outcomes After Opening-Wedge High Tibial Osteotomy in Active Patients

Background:

Although opening-wedge high tibial osteotomy (OWHTO) is favored for active patients who expect to return to sports, there is still a lack of robust evidence for factors affecting their recovery.

Purpose:

To identify (1) risk factors leading to a decreased level of return to preoperative sports after OWHTO and (2) patient characteristics and intraoperative factors influencing patient-reported outcomes after return to sports.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

Included were 69 patients who underwent OWHTO and who expected to return to their preoperative level of sports, measured as a Tegner activity level ≥2. All included patients had a minimum of 1 year of follow-up data. Logistic regression analyses were performed to assess the effect of independent variables on the level of return to preoperative sports after surgery; the independent variables were age, sex, body mass index, preoperative Tegner score, preoperative Kellgren-Lawrence grade, preoperative percentage of mechanical axis (%MA), opening gap width, concomitant meniscal treatment, postoperative %MA, postoperative medial proximal tibial angle (MPTA), and postoperative posterior tibial slope. Univariate and multiple regression analyses were performed to assess for influencing factors on postoperative International Knee Documentation Committee (IKDC) subjective scores in patients who were able to return to sports.

Results:

Of the 69 patients, 51 (73.9%) returned to sports after OWHTO. High preoperative Tegner scores were statistically associated with a decrease in return to sports (odds ratio, 1.494; P = .033). Multiple regression analysis (n = 46 patients) identified that a higher postoperative MPTA was associated with a decreased IKDC subjective score after return to sports (r = –0.345; P = .019).

Conclusion:

Higher postoperative MPTA was associated with the worsening of patient-reported outcomes among those patients who did return to their preoperative sports after OWHTO. Also, participation in high-activity sports was confirmed to be a significant risk factor for a decreased rate of return to preoperative sports. These findings can support preoperative planning and intraoperative decision making, particularly for active patients.

Does Degeneration of the Patellofemoral Joint After Medial Open-Wedge High Tibial Osteotomy Affect Clinical Outcomes?

BACKGROUND

Although biomechanical and clinical studies have reported adverse effects on the patellofemoral joint after medial open-wedge high tibial osteotomy (MOWHTO), there is a paucity of literature that describes outcomes longer than midterm follow-up.

PURPOSE

We aimed to evaluate the mid- to long-term radiologic and clinical outcomes of the patellofemoral joint after MOWHTO and to assess whether radiologic deterioration of the patellofemoral joint affected clinical outcomes or survivorship after MOWHTO.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We retrospectively reviewed 170 knees that underwent MOWHTO and had a minimum 5-year follow-up. In radiologic evaluation, serial postoperative changes in the patellofemoral joint compared with the preoperative status were evaluated on the Merchant view according to the Kellgren-Lawrence grade. The American Knee Society (AKS) score, Knee injury and Osteoarthritis Outcome Score (KOOS), Kujala score, incidence of anterior knee pain, and survivorship were used to assess clinical outcomes. Using radiologic assessment of the patellofemoral joint, we divided the patients into a radiologic progression group and a radiologic nonprogression group to evaluate whether radiologic progression of patellofemoral arthritis affected long-term clinical outcomes and survivorship after MOWHTO.

RESULTS

The mean follow-up period was 96.3 months (range, 60-163 months). Arthritic progression of the patellofemoral joint on the Merchant view was observed in 44.9%, 56.3%, 66.0%, and 84.0% of the cases at 5, 7, 9, and 11 years, respectively. Clinical outcomes such as AKS scores and KOOS significantly improved after MOWHTO (P < .001) at the latest follow-up. The incidence of anterior knee pain was 5.3% (9/170 knees). One knee (0.6%) underwent conversion to TKA due to progressive medial osteoarthritis, so the survival rate was 99.4% at a mean follow-up of 96.3 months. Despite patellofemoral degeneration over time, there were no significant differences in clinical outcomes or survivorship between patients with and without radiologic progression at the latest follow-up.

CONCLUSION

Although degeneration of the patellofemoral joint was observed with time after MOWHTO, the related symptoms were minimal and arthritic changes in the patellofemoral joint did not affect the clinical outcomes or survivorship after MOWHTO over a mid- to long-term follow-up.

Surgical planning of osteotomies around the knee differs between preoperative standing and supine radiographs in nearly half of cases

Background

To evaluate the difference in surgical planning of osteotomies around the knee between preoperative standing and supine radiographs and to identify risk factors for discrepancies in surgical planning.

Methods

This study included 117 knees of 100 patients who underwent osteotomies around the knee for knee osteoarthritis with genu varum. Surgical planning was performed so that the target point of the postoperative weight-bearing line (WBL) ratio was 62.5% in preoperative standing and supine radiographs. If the opening gap would be > 13 mm in open-wedge high tibial osteotomy (OWHTO), closed-wedge HTO (CWHTO) was planned. If the postoperative mMPTA would be > 95° in isolated HTO, double-level osteotomy (DLO) was planned. In DLO, lateral closed-wedge distal femoral osteotomy was performed so that the postoperative mechanical lateral distal femoral angle (mLDFA) was 85°, and any residual varus deformity was corrected with HTO.

Results

Surgical planning differed between standing and supine radiographs in 43.6% of cases. In all knees for which surgical planning differed between standing and supine radiographs, a more invasive type of osteotomy was suggested by standing radiographs than by supine radiographs. The risk factors for discrepancies in surgical planning were a lower WBL ratio in standing radiographs and a lower joint line convergence angle in supine radiographs.

Conclusions

Surgical planning of DLO, CWHTO and OWHTO, in standing radiographs differed from that in supine radiographs in nearly half of the cases. Surgical planning based on standing radiographs leads to more invasive surgical procedures compared to supine radiographs.

Patellofemoral cartilage defects are acceptable in patients undergoing high tibial osteotomy for medial osteoarthritis of the knee

BACKGROUND

Patients suffering cartilage defects of the medial compartment with underlying varus deformity do benefit from high tibial osteotomy (HTO) even in the long term. Nonetheless, kinematic and geometric changes especially in the patellofemoral joint have been described. Purpose of the present study was to evaluate the influence of patellofemoral cartilage defects detected during the diagnostic arthroscopy and their influence on HTO's postoperative outcome.

METHODS

Ninety patients with a mean follow-up of 10.08 ± 2.33 years after surgery were included. Patients were divided into four groups according to their cartilage status in the patellofemoral joint (A = no defects, B = isolated lesions of the patella, C = isolated lesions of the trochlea, D = kissing lesions). Functional outcome was evaluated before surgery and about ten years thereafter by relying on the IKDC, Lysholm, and KOOS scores. Radiological parameters were assessed pre- and six weeks postoperatively.

RESULTS

In groups A to D, the HTO led to significant patellar distalisation in the sagittal view, with the mean indices remaining at or above the limit to a patella baja. All patients in all groups profited significantly from HTO (higher Lysholm score, lower VAS p < 0.001), patients in group D had the lowest outcome scores. Patella height negatively influenced outcome scores in group C (Blackburne-Peel-Index-VAS p = 0.033) and D (Caton-Deschamps-Index-Tegner p = 0.018), a larger valgus correction was associated with lower outcome scores in group D (Lysholm p = 0.044, KOOSpain 0.028, KOOSQOL p = 0.004).

CONCLUSION

Long-term results of HTO for varus medial compartment osteoarthritis remain good to excellent even in the presence of patellofemoral defects. Overcorrection should be avoided. Distal biplanar HTO should be considered for patients presenting trochlear or kissing lesions of the patellofemoral joint.

TRIAL REGISTRATION

DRKS00015733 in the German Registry of Clinical Studies.

Medial Open Wedge High tibial Osteotomy (MOWHTO) does not relevantly alter patellar kinematics: a cadaveric study

PURPOSE

The purpose of this study was to quantify the influence of medial open wedge high tibial osteotomy on patellar kinematics using optical computer navigation, as anterior knee pain infrequently occurs postoperatively and the reason is still being unknown.

METHODS

Ten medial open wedge high tibial osteotomies at supratuberosity level in 5 full body specimens were performed. The effect of the surgical procedure on patellar kinematics, measured at 5 and 10 degrees of leg alignment correction angle, was analyzed and compared to native patellar kinematics during passive motion-regarding patella shift, tilt, epicondylar distance and rotation. Linear mixed models were used for statistical analysis, a two-sided p value of ≤ 0.05 was considered statistically significant.

RESULTS

Tilt behavior, medial shift and epicondylar distance did not show a significant difference regarding natural patellar kinematics at both osteotomy levels. Both osteotomy correction angles showed a significant less external rotation of the patella (p < 0.001, respectively) compared to natural kinematics.

CONCLUSIONS

Except less external rotation of the patella, medial open wedge high tibial osteotomy does not seem to relevantly alter patellar alignment during passive motion. Future clinical studies have to prove the effect of MOWHTO on patellar kinematics measured in this experimental setup, especially regarding its influence on anterior knee pain.

Increased patellar bone tracer uptake in preoperative SPECT/CT before medial opening high tibial osteotomy correlates with inferior clinical outcome

PURPOSE

The purpose of this study was to investigate whether specific bone tracer uptake (BTU) patterns on preoperative SPECT/CT could predict which patients with varus alignment and medial overload would particularly benefit from medial opening-wedge high tibial osteotomy (MOWHTO). It was the hypothesis that an increased preoperative BTU relative to the reference BTU of the femur on SPECT/CT in the lateral and patellar compartments of the knee are predictive factors for inferior clinical outcome and that the clinical outcome correlates with the extent of alignment correction.

METHODS

Twenty-three knees from 22 patients who underwent MOWHTO for medial compartment overload were investigated preoperatively using Tc-99m-SPECT/CT. BTU was quantified and localised to specific joint areas according to a previously validated scheme. Pre- and postoperative mechanical alignment was measured. Clinical outcome was assessed at a median of 24 months (range 11-30) after MOWHTO by collecting the WOMAC score.

RESULTS

Significant correlations between BTU in the patellar area and the total WOMAC score and its subcategories pain and stiffness were found. Thus, BTU in the 1sPat area (superior lateral patellar compartment) correlated with total WOMAC (rho = 0.43, p = 0.04), pain subcategory (rho = 0.43, p = 0.04), and stiffness subcategory (rho = 0.59, p = 0.003). No significant correlations were found between alignment correction, age, gender and WOMAC.

CONCLUSION

This study highlights the role of preoperative SPECT in modern knee surgery to obtain information about the loading pattern on different compartments of the knee. Despite the limited number of participants, the present study shows that a preoperative SPECT/CT scan can help the treating surgeons to identify patients who may be at risk of inferior clinical outcome if an MOWHTO is considered, as an elevated BTU in the patellar region on preoperative SPECT/CT appears to be a potential risk factor for postoperative pain and stiffness.

LEVEL OF EVIDENCE

Level III.

[Comparison of two osteotomies in the treatment of medial compartment osteoarthritis]

Objective

To compare the effectiveness of modified distal tibial tubercle-high tibial osteotomy (DTT-HTO) and open-wedge HTO (OWHTO) in the treatment of medial compartment osteoarthritis.

Methods

A clinical data of 80 patients with medial compartment osteoarthritis treated with HTO between January 2016 and January 2019 was retrospectively analyzed, including 40 patients treated with DTT-HTO (DTT-HTO group) and 40 patients treated with OWHTO (OWHTO group). There was no significant difference in gender, age, body mass index, affected side, disease duration, Kellgren-Lawrence grading of osteoarthritis, and preoperative knee society score (KSS), Hospital for Special Surgery (HSS) score, knee joint visual analogue scale (VAS) score, hip-knee-ankle angle (HKA), posterior tibial slope (PTS), weight-bearing line ratio (WBL), Blackburne-Peel index (BPI), Caton-Deschamps index (CDI), and Insall-Salvati index (ISI) between the two groups ( P>0.05). The operation time, incision length, bleeding volume, hospital stay, and complications in both groups were recorded. The KSS, HSS, and VAS scores were used to evaluated the effectiveness. A self-made questionnaire was used to evaluate the recovery of low-impact sports ability of the knee. X-ray films were used to observe the osteotomy healing and measure the HKA, PTS, WBL, and the patellar height indexes (BPI, CDI, ISI).

Results

All operations successfully completed in both groups. The OWHTO group operated longer than the DTT-HTO group ( P<0.05). There was no significant difference in the incision length, bleeding volume, and hospital stay between the two groups ( P>0.05). All incisions healed by first intention in both groups. There were 2 cases of lateral hinge fractures in the OWHTO group, and 1 case of lateral hinge fracture and 2 cases of tibial plateau fractures in the DTT-HTO group. No other complications occurred. The patients in both groups were followed up 2-4 years with an average of 2.8 years. The HSS, KSS, and VAS scores in both groups significantly improved after operation when compared with preoperative scores ( P<0.05). All scores gradually improved with the time and there were significant differences between different time points ( P<0.05). The HSS, KSS, and VAS scores were significantly better in the DTT-HTO group than in the OWHTO group at 3 months after operation ( P<0.05). There was no significant difference between the two groups at 6 months, 1 year, and 2 years ( P>0.05). At 1 year, the low-impact sports ability of the OWHTO group was rated as excellent in 8 cases, general in 25 cases, and poor in 7 cases, and as excellent in 7 cases, general in 26 cases, and poor in 7 cases of the DTT-HTO group. There was no significant difference between the two groups ( Z=-0.715, P=0.475). X-ray film reexamination showed that the osteotomies healed in both groups. The healing time was (4.52±1.23) months in the OWHTO group, and (4.23±1.56) months in the DTT-HTO group, showing no significant difference ( t=0.923, P=0.359). At immediate after operation, the HKA and WBL of the two groups significantly improved when compared with the preoperative values ( P<0.05). However, the pre- and post-operational difference was not significant between the two groups ( P>0.05). The PTS of the OWHTO group was significantly higher than preoperative value ( P<0.05), while the PTS of the DTT-HTO group was lower than preoperative value ( P>0.05). The pre- and post-operational difference between the two groups was significant ( P<0.05). BPI and CDI in the OWHTO group were significantly lower than preoperative values ( P<0.05), but there was no significant difference in ISI when compared with preoperative value ( P>0.05). There was no significant difference in the BPI, CDI, and ISI of the DTT-HTO group between pre- and post-operation ( P>0.05). The pre- and post-operational differences of BPI and CDI between the two groups were significant ( P<0.05), and there was no significant difference in the pre- and post-operational difference of ISI ( P>0.05).

Conclusion

The two osteotomies in the treatment of medial compartment osteoarthritis can significantly change the varus deformity and achieve satisfactory effectiveness. The early functional recovery of DTT-HTO is faster, which can avoid the increased PTS and patellar baja of traditional OWHTO. However, neither of the two surgical procedures can restore the patient's ideal low-impact sports ability of the knee.

A Systematic Review on Selected Complications of Open-Wedge High Tibial Osteotomy from Clinical and Biomechanical Perspectives

Background

The wedge opened during high tibial osteotomy defines the alignment correction in different body planes and alters soft tissue insertions. Although multiple complications of the surgery can be correlated to this, there is still a lack of consensus on the occurrence of those complications and their cause. The current study is aimed at clarifying this problem using a combined medical and biomechanical perspective.

Methods

We conducted a systematic review of the literature on selective complications of the surgery correlated with the angles of the opened wedge. Search topics covered tibial slope alteration, patellar height alteration, medial collateral ligament release, and model-based biomechanical simulations related to surgical planning or complications. Findings. The selection process with the defined inclusion/exclusion criteria led to the collection of qualitative and quantitative data from 38 articles. Medial collateral ligament tightness can be a valid complication of this surgery; however, further information about its preoperative condition seems required for better interpreting the results. The posterior tibial slope significantly increases, and the patellar height (using the Blackburne-Peel ratio) significantly decreases in the majority of the selected studies. Model-based biomechanical studies targeting surgical planning are mostly focused on the lower-limb alignment principles and tibiofemoral contact balancing rather than surgical complications. Interpretation. Increased posterior tibial slope, patellar height decrease, and medial collateral ligament tightness can occur due to alterations in different body planes and in soft tissue insertions after wedge opening. This study clarified that information about preoperative alignment in all body planes and soft-tissue conditions should be considered in order to avoid and anticipate these complications and to improve per surgery wedge adaptation. The findings and perspective of this review can contribute to improving the design of future clinical and biomechanical studies.

Does arthroscopic patellar denervation with high tibial osteotomy improve anterior knee pain?

PURPOSE

Patellofemoral (PF) joint osteoarthritis (OA) is a major cause of anterior knee pain. Combined PF and medial tibiofemoral (TF) OA is common in older adults. We evaluated the effect of arthroscopic patellar denervation (PD) in patients with combined TF and PFOA after malalignment correction.

METHODS

Forty-five patients [females/males, 27/18; age, 30-59 years (45.5 ± 8.50); mean body mass index, 25.15 ± 3.04 kg/m²] were treated in our department from March 2017 to March 2019. The patients were randomised into 2 groups: group A included 22 patients who underwent open-wedge high tibial osteotomy (OWHTO) and arthroscopic PD and group B included 23 patients who underwent OWHTO without denervation. The effect of denervation was statistically and clinically evaluated using the Knee injury and Osteoarthritis Outcome Score (KOOS) and Kujala (anterior knee pain score) score.

RESULTS

After 24 months, 40 patients were available for the final follow-up. The final values of KOOS and the Kujala score were significantly different between the groups (p < 0.001). For group A, the average KOOS improved from 42.73 to 72.38 (p < 0.001) and the Kujala score improved from 42 to 74.1 (p < 0.001), whereas in group B, the average KOOS improved from 39.22 to 56.84 (p < 0.001) and the Kujala score improved from 39.7 to 56.4 (p < 0.001).

CONCLUSION

Adding arthroscopic PD to OWHTO relieves anterior knee pain in patients with combined TF and PFOA and improves knee joint function and quality of life.

LEVEL OF EVIDENCE

Level I prospective randomised control clinical trial.

Increased contact area of flange and decreased wedge volume of osteotomy site by open wedge distal tibial tuberosity arc osteotomy compared to the conventional technique

PURPOSE

The purpose of this study was to evaluate the area of the osteotomy surface, including the flange and wedge volume, in open wedge high tibial osteotomy (OWHTO), distal tibial tuberosity osteotomy (DTO), and distal tibial tuberosity arc osteotomy (DTAO) using tibial sawbones. It was hypothesized that the area of the osteotomy surface, including the flange, in DTAO was larger than that in OWHTO and DTO and that the wedge volume in DTAO was smaller than that in OWHTO and DTO.

METHODS

Fifteen tibial sawbones were divided equally into three groups: OWHTO, DTO, and DTAO. The total area of the osteotomy surface in OWHTO, DTO, and DTAO was compared using image analysis software. The contact area of the flange and the wedge volume at wedge heights of 5, 10, and 15 mm were compared among osteotomy types. One-way repeated-measures analysis of variance was used to compare the total area of the osteotomy surface, the contact area of the flange, and the wedge volume at 5, 10, and 15 mm in OWHTO, DTO, and DTAO.

RESULTS

The total area of the osteotomy surface in DTO and DTAO was significantly larger than that in OWHTO (P < 0.05). The contact area of the flange in DTAO was significantly larger than that in OWHTO at each wedge height (P < 0.05). In addition, the contact area of the flange in DTAO was significantly larger than that in DTO at wedge heights of 5 and 15 mm (P < 0.05). The wedge volume in DTAO was significantly smaller than that in DTO at each wedge height (P < 0.05).

CONCLUSIONS

This study demonstrated that an increase in the flange contact area and a decrease in the wedge volume in the opening gap were found in DTAO compared to DTO. This would be an advantage for anteroposterior screw insertion from the flange to the distal tibial fragment and bone union at the osteotomy site.

Patellofemoral Osteoarthritis Progresses After Medial Open-Wedge High Tibial Osteotomy: A Systematic Review

PURPOSE

To investigate the progression of patellofemoral (PF) osteoarthritis (OA) after medial open-wedge high tibial osteotomy (OWHTO) and whether PF OA progression has an influence on clinical outcomes.

METHODS

According to the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA), EMBASE, PubMed, and Cochrane Library were searched in June 2020 for English-language studies that presented data on PF OA or cartilage degeneration before and after OWHTO. Descriptive statistics are presented.

RESULTS

Twenty studies comprising 1,173 patients were included. The mean age was 57.1 years (range 18-84) with 826 (70.4%) female. The mean follow-up was 27.1 months (range 7-144). Ten studies reported the trochlear International Cartilage Research Society (ICRS) scores, with each of these studies reporting a greater proportion of patients with grades 2-4 OA postoperatively compared with preoperatively (relative risk = 1.19-2.76, I² = 1.9%). Similarly, 7 studies reported patellar ICRS scores and found a greater proportion with grades 2-4 OA postoperatively (relative risk = 1.08-2.44, I² = 0%). Four studies assessed PF Kellgren-Lawrence grade, each of which reported a greater proportion of patients with grades 2-4 OA postoperatively (relative risk = 1.25-21.0, I² = 31%). The PF OA assessments were heterogenous, and studies using classifications except the ICRS score or Kellgren-Lawrence grade were not included in statistical analysis. Fifteen studies assessed patellar height; 10 studies reported significant decrease in patellar height after OWHTO. Only 3 studies reported clinical outcomes for patients with and without PF OA progression. Outcome reporting was variable across these studies, and a relationship between PF OA progression and clinical outcome could not be definitively determined.

CONCLUSIONS

Patients appear to have progression of PF OA after medial OWHTO. However, there are currently insufficient studies with inconsistent measurements of outcomes to make meaningful conclusions regarding the impact of PF OA on clinical outcomes.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III-IV studies.

Medialization of the mechanical axis of the tibia is related to lateralization of the tibial tuberosity in knee osteoarthritis

PURPOSE

To determine whether medialization of the proximal tibia due to a varus deformity is related to lateralization of the tibial tuberosity in varus knee osteoarthritis (OA).

METHODS

A total of 120 knees that underwent osteotomies around the knee for varus knee OA were enrolled. Mechanical medial proximal tibial angle (mMPTA) was measured on radiographs. The angle between the mechanical and anatomical axes of the tibia (angle MA) and the distance between the centre of the tibial plateau and the anatomical axis (distance MA) were measured in the coronal plane on computed tomography images. The tibial tuberosity-posterior cruciate ligament (TT-PCL) distance, the distance between the midpoint of the tibial tuberosity and the centre of the tibial plateau (TT-centre distance), and the angle between the line through the midpoint of the tibial tuberosity and the centre of the tibial plateau and the anteroposterior axis (TT-centre angle) were measured in the axial plane. The correlations of these parameters were evaluated.

RESULTS

mMPTA correlated negatively with angle MA (r = -0.37, P < 0.01) and distance MA (r = -0.55, P < 0.01). Angle MA and distance MA correlated with TT-PCL distance (r = 0.39, P < 0.01, r = 0.42, P < 0.01), TT-centre distance (r = 0.35, P < 0.01, r = 0.38, P < 0.01) and TT-centre angle (r = 0.36, P < 0.01, r = 0.36, P < 0.01).

CONCLUSIONS

Medialization of the proximal tibia due to a varus deformity may induce lateralization of the tibial tuberosity.

Good clinical outcomes and return to sports after hybrid closed-wedge high tibial osteotomy

PURPOSE

This study aimed to investigate preoperative sports participation and postoperative clinical outcomes including a return to sports (RTS) after hybrid closed-wedge high tibial osteotomy (CWHTO) for medial compartment osteoarthritis of the knee. Characteristic of Hybrid CWHTO was defined as extra-articular lateral closed and medial open wedge osteotomy.

METHODS

The patients who underwent hybrid CWHTO from January 2016 to December 2018 were retrospectively reviewed and divided them into sports and non-sports groups. The preoperative demographic and radiographic characteristics were compared in both groups. And the clinical outcomes including the Japanese Orthopaedic Association (JOA) score, visual analogue scale (VAS), Lysholm score, University of California at Los Angeles (UCLA) activity score, and RTS in the sports group were also investigated. Statistical analysis was performed for comparisons among the preoperative factors between the two groups. Influence of sports impact and bone union of fibular osteotomy was also statistically investigated for RTS.

RESULTS

Of the 161 knees (129 patients; 46 males, 83 females), 20 knees (16 patients; 13 males, 3 females; 12.3%) belonged to sports group. Although there were no significant differences regarding the age and radiographic parameters, there were significant differences in the body mass index and proportion of males between both groups. The JOA, VAS, Lysholm, and UCLA activity scores significantly improved after surgery. RTS was 80% at a mean duration of 7.2 ± 3.1 months. RTS in the high-impact sports group was significantly lower than that in the low-impact sports group (high-impact 60% vs. low-impact 100%, p = 0.043). There was no significant difference in RTS regarding bone union after fibular osteotomy.

CONCLUSION

The clinical outcomes including RTS were satisfactory in patients with hybrid CWHTO.

LEVEL OF EVIDENCE

IV.

Comparison of Long-Term Survival Analysis Between Open-Wedge High Tibial Osteotomy and Unicompartmental Knee Arthroplasty

BACKGROUND

To compare unicompartmental knee arthroplasty (UKA) and open-wedge high tibial osteotomy (OWHTO) in a long-term follow-up propensity score matching analysis.

METHODS

Patients who underwent UKA or OWHTO for unilateral medial unicompartmental osteoarthritis (OA) between 2004 and 2010 were included. The ROM, HSS score, KS score, WOMAC score, forgotten joint score, OA progression in patellofemoral and lateral compartments, and survivorship were compared within ten years of follow-up between 67 UKA and 67 OWHTO patients after propensity score matching for age, gender, body mass index, range of motion, and osteoarthritis (OA) grade.

RESULTS

At the last follow-up, there were no significant differences between the two groups in clinical outcomes, but the WOMAC score showed better results after UKA (13.1 in UKA vs 18.9 in OWHTO, P = .011). The OA progression also showed no significant difference between the two groups. After a 10-year follow-up, the survival rate was higher in UKA patients (96.2%) than in OWHTO patients (87.7%), with no statistical difference (P = .06).

CONCLUSION

UKA showed better clinical outcomes and OA progressions than OWHTO. The survival rate presented a superiority of 8.5% for the UKA group in the 10-year follow-up, without significant difference.

Proximal tibial osteotomy for genu varum: Radiological evaluation of deformity correction with a plate vs external fixator

BACKGROUND

High tibial osteotomy (HTO) is a well-known procedure for the correction of knee varus. The purpose of this study was to compare the radiological results and accuracy of deformity correction performed using two different techniques: acute opening wedge correction using a plate and gradual correction with a monolateral external fixator.

AIM

To compare of the radiological results of two different techniques: acute opening wedge correction (a plate and screw) and gradual correction (external fixator).

METHODS

A total of 43 patients with plates and 36 patients with external fixators were included. All patients had moderate uniplanar varus deformities. We measured radiographic parameters, including the mechanical axis deviation (MAD), medial proximal tibial angle (MPTA), Caton-Deschamps Index (CDI), posterior proximal tibial angle, and joint line obliquity angle (JLOA). The accuracy of MAD correction was calculated based on a correction goal of neutral or overcorrection for medial compartment arthritis.

RESULTS

Demographics including age, body mass index, sex, and preoperative deformities were similar between the groups. The MAD significantly improved from 23.6 mm medial to the midline (SD = 8.2 mm) to 6.9 mm lateral to the midline (SD = 5.4 mm) (P < 0.001). The accuracy of MAD correction did not differ between the groups and was 96.1% (SD = 8.1%) in the plate group and 98.2% (SD = 5.2%) in the external fixator group (P = 0.18). The MPTA significantly improved from 83.9° (SD = 2.9°) to 90.9° (SD = 3.3°) (P < 0.001), and the change was similar between the groups. Differences were noted in patella height, with a CDI change of -19.2% (SD = 13.7%) and 3.1% (SD = 8.0%) for the plate and external fixator groups, respectively (P < 0.001). The change in JLOA was 1.6 degrees (SD = 1.1 degrees) and 0.9 degrees (SD = 0.9 degrees) for the plate and external fixator groups, respectively (P = 0.04).

CONCLUSION

Reliable correction of moderate varus alignment was achieved with both the acute opening wedge technique with a plate and the gradual monolateral external fixator technique. The patellar height decreased with the open wedge plate technique. Joint line obliquity decreased to a greater degree with the open wedge plate technique, perhaps as a result of medial collateral ligament release. The appropriate technique should be selected based on surgeon and patient preferences; however, external fixation may be a better choice when the preservation of patellar height is deemed important.

Abrasion arthroplasty promotes improvement of degenerated femoral trochlear cartilage after medial open wedge high tibial osteotomy

OBJECTIVES

Several studies have reported negative effects of open wedge high tibial osteotomy (OWHTO) on patellofemoral joints with cartilage degeneration and recommended performing other procedures. However, if chondral resurfacing surgery could promote improvement of cartilage degeneration in the patellofemoral joint, OWHTO would be an acceptable option. The purposes of this study were to arthroscopically evaluate the femoral trochlear articular cartilage after abrasion arthroplasty combined with OWHTO and to investigate the factors promoting improvement of that cartilage.

METHODS

The present study cohort comprised 18 knees of 18 patients with varus osteoarthritis of the knee who had (1) International Cartilage Repair Society (ICRS) grade 4 femoral trochlear chondral lesions at the time of OWHTO; (2) undergone abrasion arthroplasty of the femoral trochlear cartilage in combination with OWHTO; (3) undergone second-look arthroscopy; and (4) been followed up for more than 2 years. Cartilage status was arthroscopically graded at the time of OWHTO and second-look arthroscopy. Patients were allocated to two groups according to the status of the femoral trochlear cartilage at the time of second-look arthroscopy: the improved group comprised patients with an ICRS grade of less than 3, and the not improved group comprised those with an ICRS grade of 4. Clinical outcomes, expressed as Knee Injury and Osteoarthritis Outcome Score (symptoms, pain, activities of daily living, function in sports/recreation and quality of life) and selected radiographic variables were compared between the two groups.

RESULTS

There were 11 (61%) knees in the improved group and 7 (39%) in the not improved group. A comparison of radiographic variables between the two groups revealed that neither limb alignment nor patellar height affected cartilage changes. The two groups had similar results on the symptoms, pain, sports/recreation and activities of daily living subscales of the Knee Injury and Osteoarthritis Outcome Score. However, the quality of life subscale significantly differed between the two groups (p=0.025).

CONCLUSION

Degenerated femoral trochlear cartilage can improve after combined abrasion arthroplasty and OWHTO. A comparison of clinical outcomes between the improved and not improved groups revealed that neither radiographic variables nor clinical symptoms, including pain, affected cartilage changes at short-term follow-up.

LEVEL OF EVIDENCE

Case series, level V.

Preoperative flexion contracture is a predisposing factor for cartilage degeneration at the patellofemoral joint after open wedge high tibial osteotomy

Purpose

The purpose of the study was to determine the effect of cartilage degeneration at the patellofemoral joint on clinical outcomes after open wedge high tibial osteotomy and to investigate the predisposing factors for progressive patellofemoral cartilage degeneration.

Methods

Seventy-two knees were evaluated on second-look arthroscopy in patients who opted for plate and screw removal at an average of 20.1 months after osteotomy. Cartilage degeneration at the patellofemoral joint was evaluated using the International Cartilage Repair Society grading system, with cases divided into progression and nonprogression groups. Radiographic parameters of the patellofemoral anatomy, knee range of motion, and clinical outcomes were evaluated from the preoperative baseline to the final follow up, on average 50 months after osteotomy. A contracture > 5° was considered a flexion contracture.

Results

Cartilage degeneration progressed in 31 knees, and preoperative knee flexion contracture was significantly associated with progressive degeneration (P < 0.01). The Lysholm and Kujala scores were significantly lower in the progression group (87.9 and 85.3, respectively) than in the nonprogression group (91.6 and 93.6, respectively) (P < 0.05). The odds ratio of the flexion contracture resulting in progression of patellofemoral cartilage degeneration was 4.63 (95% confidence interval, 1.77–12.1). No association was detected between progressive degeneration and age, sex, body mass index, Kellgren-Lawrence grade, or radiographic parameters.

Conclusions

Flexion contracture may be associated with progression of cartilage degeneration at the patellofemoral joint and may negatively affect the clinical outcomes after open wedge, high tibial osteotomy.

Distal tibial tubercle osteotomy is superior to the proximal one for progression of patellofemoral osteoarthritis in medial opening wedge high tibial osteotomy

PURPOSE

To investigate the effect of proximal tibial tubercle osteotomy (PTO) and distal tibial tubercle osteotomy (DTO) in medial opening wedge high tibial osteotomy on patellofemoral alignment, patellofemoral osteoarthritis and clinical outcomes.

METHODS

PTO (n = 41) and DTO (n = 43) for the same surgical indications were included. Radiographic measurements of the Caton-Deschamps index, patellar tilt and shift, and arthroscopic cartilage evaluation at the patellofemoral joint were performed at osteotomy and plate removal. The Knee Society Score (KSS) was evaluated preoperatively and at the latest follow-up.

RESULTS

The follow-up period was longer in the PTO group (33.7 months; range 23-40 years) than in the DTO group (22.2 months; range 18-29 months) (p < 0.0001), whereas the period from osteotomy to plate removal was not different between the groups. The Caton-Deschamps index of the DTO group was unchanged from 0.9 (range 0.7-1.2) to 0.9 (range 0.6-1.4), whereas that of the PTO group changed from 0.9 (0.7-1.2) to 0.7 (0.5-1.0) (p < 0.0001). There were fewer deteriorated cases of cartilage status in the trochlear groove in the DTO group (20.9%) than in the PTO group (56.1%, p < 0.05). There were more improved cases in the DTO group (23.3%) than in the PTO group (4.9%, p < 0.05). Postoperative KSS was better in the DTO group than in the PTO group (p < 0.05).

CONCLUSION

DTO is associated not only with reduced deterioration but also with increased improvement of cartilage status in the trochlear groove and better KSS as compared with PTO.

LEVEL OF EVIDENCE

IV.

Patellofemoral Cartilage Degeneration After Closed- and Open-Wedge High Tibial Osteotomy With Large Alignment Correction

BACKGROUND

Previous studies have reported patellofemoral cartilage degeneration and analyzed the factors affecting degeneration after open-wedge high tibial osteotomy (OWHTO). However, no studies have evaluated patellofemoral cartilage degeneration or examined the factors affecting degeneration after closed-wedge high tibial osteotomy (CWHTO).

PURPOSE

To investigate and compare patellofemoral cartilage degeneration after CWHTO and OWHTO via arthroscopic evaluation and to analyze the factors affecting the degeneration.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 54 CWHTOs and 50 OWHTOs were performed with first-look arthroscopy between 2013 and 2017 at one institution. Hardware removal and second-look arthroscopy were performed, on average, 30.2 months after CWHTO and 26.8 months after OWHTO (P = .178). Patient characteristics did not differ significantly between the groups. Radiographically, the mechanical axis, posterior tibial slope, and modified Blackburne-Peel ratio were evaluated. Arthroscopically, the percentage of patient with patellofemoral cartilage degeneration was evaluated according to the International Cartilage Repair Society grading system. Logistic regression analysis was used to identify the factors affecting patellofemoral cartilage degeneration in terms of demographics and the change of mechanical axis (correction angle), tibial posterior slope angle, and modified Blackburne-Peel ratio. The Anterior Knee Pain Scale was used for clinical comparison between the patellofemoral degenerative and nondegenerative groups.

RESULTS

No significant differences were observed in pre- and postoperative radiographic results between the CWHTO and OWHTO groups, except that the postoperative modified Blackburne-Peel ratio was significantly smaller among the OWHTOs. The percentage of patients with patellofemoral cartilage degeneration were 29.6% in the CWHTO group and 44% in the OWHTO group (P = .156) at second-look arthroscopy. The correction angle was the only significant factor affecting cartilage degeneration in the CWHTO group (odds ratio, 2.324; P = .013; cutoff value, 9.6°) and the OWHTO group (odds ratio, 1.440; P = .041; cutoff value, 10.1°). The postoperative Anterior Knee Pain Scale score was significantly lower in the patellofemoral degenerative group as compared with the nondegenerative group among the OWHTO group (81.6 vs 76.4; P = .039); among the CWHTO group, there was a lower tendency in the degenerative group, but this was without significance (81.1 vs 79.6; P = .367).

CONCLUSION

Patellofemoral cartilage degeneration progressed after CWHTO and OWHTO with large alignment correction. High tibial osteotomy should be selected with careful consideration of the osteoarthritic status of the patellofemoral joint and required correction angle, regardless of applying a closed- or open-wedge technique.

Clinical Outcomes and Complications During and After Medial Open-Wedge High Tibial Osteotomy Using a Locking Plate: A 3- to 7-Year Follow-up Study

Background:

Outcomes and complications at mid- or long-term follow-up after medial open-wedge high tibial osteotomy (MOWHTO) with the TomoFix locking plate have not been fully evaluated.

Purpose:

To evaluate the complications and midterm clinical outcomes after MOWHTO using a TomoFix.

Study Design:

Case series; Level of evidence, 4.

Methods:

Enrolled in this study were 80 patients (85 knees) who underwent MOWHTO with the TomoFix locking plate between 2009 and 2013. There were 66 women and 14 men, with a mean age of 61.5 years at the time of surgery. The diagnosis was medial osteoarthritis in 76 knees and spontaneous osteonecrosis of the knee in 9 knees. Metal removal and second-look arthroscopy were performed in all cases. Clinical and radiological examinations were performed at final follow-up after surgery (mean, 4.5 years).

Results:

The mean Japanese Orthopaedic Association score and Knee injury and Osteoarthritis Outcome Score improved significantly from pre- to postoperatively (P < .0001). The weightbearing line percentage shifted to pass through a point 67.7% lateral from the medial edge of the tibial plateau. The Caton-Deschamps index changed significantly from 0.88 to 0.66 at final follow-up (P < .0001). The mean posterior tibial slope changed significantly from 8.9° to 11.9° at final follow-up (P < .0001). Limb length was significantly increased after MOWHTO (10.3 mm; P < .0001). During plate removal, 14 locking screws were found to be broken in 9 knees (10.6%). The articular cartilage grade of the patellofemoral joint was significantly higher in the second arthroscopy than in the first arthroscopy (P < .0001). The cumulative rate of all complications was 41.2%, with major complications (ie, those requiring additional or extended treatment) in 24.7%.

Conclusion:

Postoperative outcome scores indicated significant improvement after MOWHTO, although the cumulative rate of all complications was 41.2% and the rate of major complications was 24.7%. These results indicate that MOWHTO with the TomoFix is a technically demanding procedure. Careful preoperative planning and meticulous surgical technique are needed to decrease the incidence of complications associated with MOWHTO.

Distal tuberosity osteotomy in open-wedge high tibial osteotomy does not exacerbate patellofemoral osteoarthritis on arthroscopic evaluation

PURPOSE

The purpose of the present study was to use arthroscopy to evaluate the effect of distal tuberosity osteotomy (DTO) in open-wedge high tibial osteotomy (OW-HTO) on patellofemoral (PF) cartilage degradation.

METHODS

Between 2012 and 2017, 46 knees underwent DTO in OW-HTO, and 65 knees underwent conventional OW-HTO (cOW-HTO). To assess changes in patellar height, the Blackburne-Peel (BP) ratio and the Caton-Deschamps (CD) index were measured. Arthroscopic evaluation on the PF joint was performed at the initial osteotomy and at the second-look procedure 1 year later. Statistical analyses were performed to compare difference between the DTO and the cOW-HTO group.

RESULTS

In the cOW-HTO group, the mean BP ratio and CD index decreased significantly from 0.81 and 0.89 preoperatively, respectively, to 0.69 and 0.76 postoperatively, respectively (p < 0.001). In contrast, the DTO group maintained a consistent patellar height; the mean BP ratio and CD index were 0.77 and 0.83 preoperatively, respectively, and 0.73 and 0.80 postoperatively, respectively. Upon arthroscopic evaluation, 39 of 46 patients (84.8%) in the DTO group showed no progression of PF cartilage degradation at the second look; indeed, five of 46 patients (10.9%) even demonstrated improvement. In contrast, 21 of 65 patients (32.3%) in the cOW-HTO group exhibited increased PF cartilage degradation. There was a significant difference in progression of PF cartilage degradation between DTO and cOW-HTO (p < 0.001).

CONCLUSION

DTO in OW-HTO maintained the preoperative patellar height, which could help prevent progression of cartilage degeneration in the PF joint after surgery. In respect of the biplanar osteotomy direction in OW-HTO, the DTO, rather than cOWHTO, is the preferred technique for the treatment of varus knee osteoarthritis to avoid progression of PF cartilage degradation.

LEVEL OF EVIDENCE

III.

Tibial condylar valgus osteotomy - indications and technique

PURPOSE

To describe the indications for, and surgical technique of, tibial condylar valgus osteotomy (TCVO).

INDICATIONS

TCVO is commonly performed in patients with middle-to-end-stage medial unicompartmental osteoarthritis. Among the most important TCVO indication criteria are the types of tibial plateau shape. The convex-type (also called "pagoda-type"), with over a 5° joint line convergence angle on the standing X-ray, meets the indication criteria for TCVO.

SURGICAL TECHNIQUE

An L-shaped osteotomy is performed from the medial side of the proximal tibia to the lateral beak of the intercondylar eminence. The apex of the L-shaped osteotomy line is on the medial border of the patellar tendon insertion. Surgeons should note the direction of the chisel (during the osteotomy) to the intercondylar eminence following fluoroscopic guidance. The posterior cortical bone is cut under a lateral view observation, and the crossed-leg position is adopted to prevent injury to the popliteal blood vessels. The spreader should be positioned at the posterior cortical bone to avoid increasing the tibial slope. The locking plate reliably stabilizes the osteotomy and helps shorten the period of postoperative rehabilitation.

CONCLUSIONS

TCVO adjusts varus deformity alongside joint congruity. Accurate identification of indications and a detailed surgical plan would ensure effective correction and proper alignment. Additional osteotomies are recommended in case of under-correction of the varus limb deformity. TCVO is an effective intervention in patients with advanced knee osteoarthritis and lateral joint laxity with the pagoda-type tibial plateau shape.

The effect of medial open wedge high tibial osteotomy on the patellofemoral joint: comparative analysis according to the preexisting cartilage status

BACKGROUND

Although it has been known that medial open wedge high tibial osteotomy (MOWHTO) would adversely affect the patellofemoral joint, no previous study examined the surgical outcome of MOWHTO according to the preexisting cartilage status of the patellofemoral joint. The aim of this study was to investigate the effect of MOWHTO on the patellofemoral joint with regard to objective and subjective aspects according to the preexisting cartilage status.

METHODS

Ninety-two patients who underwent MOWHTO and a following second-look arthroscopic assessment were included in this study. The patients were divided into two groups according to the preexisting cartilage status of the patellofemoral joint: group 1 (International Cartilage Repair Society [ICRS] grade 2 or 3) and group 2 (ICRS grade 0 or 1). Comparative analysis was performed regarding clinical scores, radiographic parameters, and arthroscopic measurements between the two groups.

RESULTS

Clinical outcomes showed overall improvement from baseline to the time of second-look operation, with no significant difference between the two groups at each time point. There were no significant differences in radiographic parameters between the two groups. Radiographic grade of patellofemoral osteoarthritis in both groups showed a tendency to progress, without statistical significance. In arthroscopic assessment, the size of the cartilage lesion on the patellofemoral joint increased with time in both groups (P = 0.003), but the degree of change over time between the two groups was not statistically significant. Consistently, there was no significant difference in the frequency of progression of cartilage lesion grade in the patellofemoral joint between the two groups.

CONCLUSIONS

MOWHTO would contribute to osteoarthritis progression of the patellofemoral joint regardless of the preexisting cartilage status, without an association with clinical outcomes in short-term follow-up.

Effect of Medial Open-Wedge High Tibial Osteotomy on the Patellofemoral Joint According to Postoperative Realignment

BACKGROUND

No study has yet assessed the effect of medial open-wedge high tibial osteotomy (MOWHTO) on the patellofemoral joint according to postoperative alignment.

PURPOSE

To evaluate the effect of MOWHTO on the patellofemoral joint according to postoperative alignment by comparing the cartilage status before and after surgery and assessing the clinical and radiological outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 135 patients who underwent MOWHTO were retrospectively investigated. The patients were divided into 3 groups according to the postoperative weightbearing line ratio (WBLR): undercorrection (WBLR <58.3%, lowest quartile), acceptable correction (WBLR of 58.3%-66.3%, middle 2 quartiles), and overcorrection (WBLR >66.3%, highest quartile). The postoperative change in the cartilage status was assessed arthroscopically during implant removal at 2 years after MOWHTO. The clinical and radiological outcomes were evaluated at a mean follow-up of 52.1 months. A regression analysis was performed to identify the factors affecting the deterioration of the patellofemoral joint cartilage status. A receiver operating characteristic curve was employed to identify the cutoff point for the postoperative WBLR associated with the deterioration of the cartilage status in the patellofemoral joint.

RESULTS

Of all patients, progression of cartilage degeneration was noted in 39.3% for femoral trochlea and 23.7% for patella. The incidence of cartilage progression was significantly higher in the overcorrection group than in the undercorrection and acceptable correction groups (femoral trochlea: undercorrection group = 30.3%, acceptable correction group = 32.4%, and overcorrection group = 61.8% [P = .008]; patella: undercorrection group = 15.2%, acceptable correction group = 17.7%, and overcorrection group = 44.1% [P = .005]). The functional outcomes, including Lysholm knee score, Knee injury and Osteoarthritis Outcome Score (Pain, Symptoms, and Activities of Daily Living subscales), and Shelbourne and Trumper score, were significantly worse in the overcorrection group. The regression analysis showed that only the postoperative WBLR had a significant effect on cartilage deterioration. The cutoff point for the postoperative WBLR associated with progression of the International Cartilage Repair Society grade was 62.1% for the femoral trochlea (sensitivity = 61.5%, specificity = 62.7%, accuracy = 66.2%) and 62.2% for the patella (sensitivity = 59.4%, specificity = 60.2%, accuracy = 67.8%).

CONCLUSION

The patellofemoral joint was adversely affected by MOWHTO. Overcorrection causing excessive valgus alignment led to further progression of degenerative changes in the patellofemoral joint and inferior clinical outcomes. The postoperative WBLR can be used as a predictive factor for deterioration of the cartilage status in the patellofemoral joint after MOWHTO.

Editorial Commentary: Does Patellofemoral Degenerative Progression After Open-Wedge High Tibial Osteotomy Adversely Affect Clinical Outcomes?

Open-wedge high tibial osteotomy causes deterioration of the patellofemoral cartilage status. However, whether patellofemoral degenerative progression adversely affects clinical outcomes remains unclear, thereby necessitating a comprehensive long-term follow-up study.