The SPECT/CT Evaluation of Compartmental Changes after Open Wedge High Tibial Osteotomy

Single-Joint Type Hybrid Assistive Limb for Knee Training in the Acute Postoperative Phase After Opening Wedge High Tibial Osteotomy: A Feasibility and Safety Trial

BACKGROUND AND OBJECTIVE

Opening wedge high tibial osteotomy (OWHTO) influences the knee extensor mechanism, the range of passive motion of knee extension and persistent quadriceps, and anterior knee pain and weakness. Rehabilitation should focus on quadriceps strength and improving joint mobility. The single-joint hybrid assistive limb device (HAL-SJ) is a wearable exoskeleton cyborg. In this study, we investigated the feasibility and safety of HAL-SJ training after the early postoperative period following OWHTO and whether the use of this device can improve functional outcomes, including knee muscle extensor strength and knee extension range of motion without knee pain.

METHODS

Patients who had been diagnosed with knee osteoarthritis and had undergone OWHTO were assessed for eligibility in this prospective trial conducted at our institution between June 2015 and November 2020. The participants were split into two groups, i.e., 10 patients in the hybrid assistive limb (HAL) group and eight patients in the control group. We initiated HAL-SJ therapy on postoperative day 8 and continued it until the patient's discharge. During the hospitalization period, patients engaged in HAL-SJ-assisted knee extension exercises. This exercise routine encompassed five sets, each comprising 10 repetitions, and was conducted twice a week. We conducted assessments aimed at detecting any potential adverse events that could be linked to HAL training. Assessment of the knee extension angle via the visual analog scale (VAS) and strength assessments using a hand-held dynamometer (HHD) were conducted. To compare clinical outcomes before and after OWHTO, knee extension angle, the VAS, HHD, Japanese Orthopaedics Association (JOA) score, and the Japanese Knee Osteoarthritis Measure (JKOM) were assessed at four distinct time points.

RESULTS

No adverse events were observed during the study. The assessment of clinical outcomes before and after OWHTO demonstrated a gradual improvement in outcomes.

CONCLUSION

The single-joint hybrid assistive limb device in patients who underwent OWHTO appears to be potentially safe. It contributed to enhanced muscle activity efficiency by reducing knee pain and improving knee extension angles in the early postoperative phase.

Serial Quantitative Assessment of Load Redistribution After Medial Open-Wedge High Tibial Osteotomy

Background

The maximum standardized uptake value (SUV_max), as determined on combined single-photon emission computed tomography and conventional computed tomography (SPECT/CT), can be an indicator of biomechanical changes due to the load redistribution effect after medial open-wedge high tibial osteotomy (MOW-HTO).

Purpose/Hypothesis

The purposes of this study were to (1) analyze serial changes in the SUV_max in the medial, lateral, and patellofemoral compartments after MOW-HTO and (2) identify the contributing factors that affect changes in the SUV_max. The hypotheses were that (1) an elevated SUV_max in the medial compartment would be transferred to the lateral compartment because of the load redistribution effect and (2) there would be contributing factors that cause SUV_max changes.

Study Design

Case series; Level of evidence, 4.

Methods

Included were 67 knees that were treated with biplanar MOW-HTO between March 2019 and December 2020. SPECT/CT was performed immediately after surgery and at 3 months and 1 year postoperatively to determine the serial load redistribution effect of MOW-HTO. The Pearson correlation coefficient was used to evaluate the relationship between SUV_max and radiological parameters, and subgroup analyses were conducted to compare the SUV_max according to associated cartilage procedures and the weightbearing line ratio (WBLR).

Results

The SUV_max in the medial and lateral compartments increased at 3 months but decreased at 1 year postoperatively. The load redistribution effect was most prominent in the anterior zones of the femur (medial: P = .041; lateral: P = .012). In the patella, the SUV_max decreased in both the medial and the lateral zones at all follow-up times (P < .001 for all). The SUV_max in the anterolateral and posterolateral articular zones of the femur increased with a greater preoperative WBLR (r = 0.256, P = .039; and r = 0.261, P = .036, respectively). Patients who underwent an associated cartilage procedure had a significantly higher SUV_max in the anteromedial and posteromedial articular zones of both the femur and the tibia at 1 year postoperatively (P ≤ .002 for all).

Conclusion

After MOW-HTO, the unloading effect in the anteromedial articular zone of the femur was the most significant. A greater SUV_max in the lateral zones of the femur was observed in cases of overcorrection. The SUV_max in the medial zones was higher postoperatively in patients with associated cartilage procedures.

Clinical Usefulness of SPECT/CT for Assessing Postoperative Outcomes After Medial Opening-Wedge High Tibial Osteotomy

Background:

Qualitative studies have explored changes in Tc-99m hydroxymethylene diphosphonate (HDP) uptake on single-photon emission computed tomography and computed tomography (SPECT/CT) as a result of offloading after medial opening-wedge high tibial osteotomy (MOWHTO) in patients with medial compartment knee osteoarthritis. However, whether changes in the Tc-99m HDP uptake on SPECT/CT reflect the degree of clinical improvement in postoperative outcomes, especially when using minimal clinically important differences (MCIDs), has not been investigated.

Purpose:

To investigate the association between changes in Tc-99m HDP uptake on SPECT/CT and MCID-based improvement on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score in patients who underwent MOWHTO.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

The study included 35 knees in 31 patients who underwent MOWHTO. SPECT/CT was performed preoperatively and 3 years postoperatively with clinical and radiological assessments. On SPECT/CT, the knee joint was divided into 10 regions, and the radiotracer uptake amount of each region was divided by the uptake amount of the reference zone. Patients were divided into 2 groups based on whether they achieved the MCID of 16.1 points on the WOMAC at 3 years postoperatively, and changes in uptake amount on SPECT/CT were compared between the groups.

Results:

At 3 years postoperatively, 22 patients achieved the MCID on the WOMAC (62.9%; above-MCID group) and 13 patients did not (37.1%; below-MCID group). In the above-MCID group, significant improvement was observed in the WOMAC after MOWHTO (from 55.8 to 19.6; P < .05); however, significant improvement was not observed in the below-MCID group (from 38.8 to 32.3; P = .100). Based on mean change of uptake on SPECT/CT in each region, the above-MCID group showed significantly greater reduction of uptake on SPECT/CT than the below-MCID group in the femoral anteromedial compartment (P = .004), tibial anteromedial compartment (P = .009), and tibial anterolateral compartment (P = .031).

Conclusion:

Reduction in radiotracer uptake on SPECT/CT of the knee joint reflected clinical improvement in patient-reported outcomes following MOWHTO.

Patellofemoral Joint after Opening Wedge High Tibial Osteotomy: A Comparative Study of Uniplane versus Biplane Osteotomies

OBJECTIVE

To the best of our knowledge, there has been no comparative study of changes in radiographic parameters in the sagittal plane between biplane opening wedge high tibial osteotomy (OWHTO) with plate fixation and uniplane OWHTO with spacer implantation. The aim of the study was to compare sagittal radiographs between the procedures of biplane and uniplane OWHTOs in patients with genu varum and to investigate the impact on the patellofemoral joint.

METHODS

A retrospective study of 71 patients (58.0 ± 5.0 years of age, 58 females and 13 males) with varus-aligned medial compartment knee osteoarthritis treated with OWHTO was performed during the period from January 2016 to February 2019. Thirty-three patients underwent biplane osteotomy with plate fixation (biplane group), and 38 patients underwent uniplane osteotomy with absorbable wedged spacer fixation (uniplane group). Independent t tests were used to compare the two groups according to the preoperative and postoperative radiographic parameters of hip-knee-ankle (HKA) angle, posterior tibial slope (PTS), tibial tubercle prominence (TTP), Caton-Deschamps (CD) index, and Blackburne-Peel (BP) index. During the last follow-up assessment, patients were asked to rate their patellofemoral joint status using the Samsung Medical Center (SMC) patellofemoral (PF) scoring system. The visual analog scale (VAS) was also used to rate knee joint pain when walking.

RESULTS

There was no significant difference between the two groups in any of the demographic, clinical, or radiological characteristics at baseline (p > 0.05). Comparisons of postoperative sagittal radiographic parameters between patients in the uniplane group and patients in the biplane group showed significant differences in the PTS (13.4° vs 16.6°, t = 4.465, p < 0.001), TTP (9.0 mm vs 4.2 mm, t = 7.950, p < 0.001), and CD index (0.81 vs 0.70, t = 4.035, p < 0.001). At the final follow-up assessment (minimum, 2 years), the SMC PF function score was significantly lower in patients in the uniplane group than in patients in the biplane group (27.8 vs. 32.1, t = 2.458, p = 0.016), but there were no significant differences in the SMC PF pain score or VAS score (p > 0.05).

CONCLUSION

The essential difference in the postoperative sagittal radiographic changes between biplane and uniplane OWHTO was the tibial tubercle prominence, indicating the posterior displacement of the tibial tubercle. Uniplane OWHTO may yield better function of the patellofemoral joint compared to biplane OWHTO.

Change of joint-line convergence angle should be considered for accurate alignment correction in high tibial osteotomy

Background

The alignment correction after high tibial osteotomy (HTO) is made both by bony correction and soft-tissue correction around the knee. Change of the joint-line convergence angle (JLCA) represents the soft-tissue correction after HTO, which is the angle made by a tangential line between the femoral condyles and the tibial plateau. We described the patterns of JLCA change and related factors after HTO and investigated the appropriate preoperative planning method.

Methods

Eighty patients who underwent HTO between 2013 and 2016 were included for this retrospective study. Standing, whole-limb radiograph, supine knee anteroposterior (AP) and lateral were measured on the preoperative and postoperative radiographs. The patterns of JLCA changes and related factors were analyzed.

Results

JLCA decreased by a mean of 0.9° ± 1.2° (P < 0.001) after HTO. Sixteen patients (20%, group II) showed a greater JLCA decrease ≥ 2°, while 64 (80%, group I) patients remained in a narrow range of JLCA change < 2°. Group II showed more varus deformity (varus 8.1° vs. varus 4.7° in the mechanical femorotibial angle, P < 0.001), greater JLCA on standing (4.9° vs. 2.1°, P < 0.001), and the difference of JLCA in the standing and supine positions (2.8° vs. 0.7°, P < 0.001) preoperatively compared to group I. The risk of a greater JLCA decrease ≥ 2° was associated with greater preoperative JLCA in the standing position and the difference between the JLCA in the standing and supine positions. Postoperative JLCA correlated better with preoperative JLCA in the supine position than those in the standing position. A preoperative JLCA ≥ 4° or the difference of preoperative JLCA in the standing and supine positions ≥ 1.7° was the cut-off value to predict a large JLCA decrease ≥ 2° after HTO in the receiver operating characteristic (ROC) curve analysis.

Conclusions

Surgeons should consider the effect of the JLCA change during the preoperative planning and intraoperative procedure to avoid unintended overcorrection.

Rotational Changes in the Tibia After High Tibial Valgus Osteotomy: A Comparative Study of Lateral Closing Versus Medial Opening Wedge Osteotomy

BACKGROUND

After high tibial valgus osteotomy (HTO), rotational changes in the tibia may occur, which can affect the biomechanics of the patellofemoral joint and may lead to anterior knee pain.

PURPOSE

To compare the rotational changes in the tibia between closing wedge HTO (CWHTO) and opening wedge HTO (OWHTO).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Among the patients who underwent HTO between May 2012 and August 2015, 53 (28 CWHTO and 25 OWHTO) who had computed tomography scans before and at 1 year after the HTO were included. The following parameters were compared between CWHTO and OWHTO: (1) tibial torsion angle, (2) knee rotation angle, and (3) tibial tuberosity-trochlear groove (TT-TG) distance. During the last follow-up, patients were asked to rate their anterior knee pain when climbing the stairs, using the visual analog scale.

RESULTS

The tibial torsion angle significantly decreased (internal rotation of the distal fragment) after CWHTO (mean ± SD, -2.1°± 4.1°; P = .019) and OWHTO (-1.8°± 3.3°; P = .029). The knee rotation angle significantly decreased (external rotation of the proximal fragment) after OWHTO (-1.8°± 3.4°; P = .039) but was not changed after CWHTO (0.1°± 3.1°; P = .859). The mean TT-TG distance significantly decreased after CWHTO (-3.1 ± 3.0 mm; P < .001) but increased after OWHTO (2.0 ± 4.3 mm; P = .012). At the final follow-up (minimum, 4 years), the visual analog scale pain score during stair climbing was significantly higher after OWHTO than after CWHTO (3.1 ± 1.4 vs 2.2 ± 1.3, P = .024).

CONCLUSION

Internal rotation of the distal fragment occurred after both CWHTO and OWHTO. However, external rotation of the proximal fragment and increased TT-TG distance occurred after OWHTO. Because such rotational changes could affect anterior knee pain, further studies are warranted to investigate the definite relationship between tibial rotational changes and anterior knee pain after HTO.

Five years of clinical and radiological results with biplanar tibial open-wedge osteotomy: feasible option to prevent patella infera?

INTRODUCTION

High tibial osteotomy (HTO) was a treatment option for relatively young active patients with isolated medial compartment arthritis of the knee. This report showed clinical and radiological results of a new HTO technique, that uses a particular open-wedge high tibial osteotomy by incorporating the tibial tubercle into osteotomy line (TT-OWHTO) to preserve patella height.

MATERIALS AND METHODS

Preoperative and postoperative function was recorded on the IKDC score, Kujala PF score, EQ-VAS and Tegner activity scale. Radiological patella height was measured with Insall-Salvati index. All this clinical and radiological recorded data on 45 active patients, with an average age of 40.2 years who underwent this procedure, allowed to do a retrospective analysis.

RESULTS

All the patients reported improvement in symptoms with an average preoperative IKDC score from preoperative value 49.7-92.3 at last follow-up. Kujala PF score improves from 67.2 preoperative value to 91.4. EQ-VAS self-assessment of quality of life reported a preoperative value of 41.2-92.2 at last follow-up. There was 2.5 point average improvement in Tegner activity scale. Patella height was not altered with median preoperative value of 0.84 ± 0.1 and final follow-up value of 0.81 ± 0.2 on Insall-Salvati index.

CONCLUSIONS

TT-OWHTO showed to be able to achieve good clinical and radiological results maintaining patella height unchanged and ensuring safety and reproducibility as much as the traditional technique.

Are There Harmful Effects of Preoperative Mild Lateral or Patellofemoral Degeneration on the Outcomes of Open Wedge High Tibial Osteotomy for Medial Compartmental Osteoarthritis?

Background

Early osteoarthritis of the knee joint mostly affects the medial compartment, making osteotomy a rational approach to slow the progression of the disease. However, some patients show asymptomatic mild degeneration in the lateral or patellofemoral compartment.

Purpose

To evaluate the effect of asymptomatic mild lateral or patellofemoral degeneration on the outcomes of medial open wedge high tibial osteotomy (OWHTO) by assessing the outcomes according to the preoperative status of the lateral or patellofemoral degenerative changes.

Study Design

Cohort study; Level of evidence, 3.

Methods

A total of 114 patients (121 knees) who underwent biplanar OWHTO with second-look arthroscopic surgery and postoperative magnetic resonance imaging (MRI) were retrospectively enrolled. Patients were categorized into 4 groups according to the Osteoarthritis Research Society International (OARSI) and MRI Osteoarthritis Knee Score (MOAKS) classification systems. The International Cartilage Repair Society (ICRS) grade was used to evaluate the preoperative and postoperative cartilage status. Clinical outcomes were assessed by the American Knee Society (AKS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-item Short Form Health Survey (SF-36).

Results

No degenerative changes in the lateral and patellofemoral compartments of knees (group I) were identified in 51.2% of cases (62 knees). Asymptomatic degenerative changes only in the lateral compartment (group II: OARSI grades 1-3 and MOAKS grades 1-3) were identified in 15.7% of cases (19 knees), changes only in the patellofemoral compartment (group III: OARSI grades 1-3 and MOAKS grades 1-3) were identified in 10.7% of cases (13 knees), and changes in both the lateral and the patellofemoral compartments (group IV) were identified in 22.3% of cases (27 knees). In the medial compartment, there was no significant difference in the improvement of MOAKS and ICRS grades among all groups (P = .813 and .985, respectively). In the lateral and patellofemoral compartments, there was no significant difference in the decline of MOAKS (P = .649 and .421, respectively) and ICRS grades (P = .927 and .676, respectively) among all groups.

Conclusion

The presence of mild lateral or patellofemoral degenerative changes did not affect the MRI, arthroscopic, and clinical outcomes of OWHTO. However, long-term observations are necessary to draw definitive conclusions as to whether OWHTO can be indicated in such patients without harmful effects.

Analysis and quantification of bone healing after open wedge high tibial osteotomy

Background

The aim of this study was to analyze radiographic imaging techniques and to quantify bone ossification in the osteotomy gap after high tibial osteotomy.

Material and methods

Study phase 1: high tibial osteotomy was performed on six lower extremities of human body donors and experimental X‑rays and computed tomography (CT) scans were applied. Different techniques were evaluated by three specialists for best representation of the osteotomy gap.

Study phase 2: optimized radiological techniques were used for follow-up on 12 patients. The radiographs were examined by 3 specialists measuring 10 different parameters. The CT scans were analyzed with semiautomatic computer software for quantification of bone ossification.

Results

The osteotomy gap was best represented in 30° of flexion in the knee and 20° internal rotation of the leg. There were significant changes of the medial width over time (p < 0.019) as well as of the length of fused osteotomy, the Schröter score, sclerosis, trabecular structure and zone area measurements. Sclerosis, medial width of the osteotomy and area measurements were detected as reproducible parameters. Bone mineral density was calculated using CT scans, showing a significantly higher value 12 weeks postoperatively (112.5 mg/cm³) than at baseline (54.6 mg/cm³). The ossification of the gap was visualized by color coding.

Conclusion

Sclerosis and medial width of the osteotomy gap as well as area measurements were determined as reproducible parameters for evaluation of bone healing. Quantification of bone ossification can be calculated with CT scans using a semiautomatic computer program and should be used for research in bone healing.

Assessment of unloading effects after open wedge high tibial osteotomy using quantitative bone scintigraphy

INTRODUCTION

We evaluated changes in bone tracer uptake (BTU) in open wedge high tibial osteotomy (OWHTO) and determined if BTU correlates with clinical symptoms, postoperative alignment, or cartilage regeneration after OWHTO.

MATERIALS AND METHODS

Seventy-five knees in 64 patients who underwent OWHTO for medial compartment osteoarthritis were enrolled in this retrospective study. All cases were assessed preoperatively and at plate removal using bone scintigraphy. Visual analog scale (VAS), Japanese Orthopedic Association (JOA) score, Oxford Knee Score (OKS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and the weight-bearing line ratio (WBLR) were assessed preoperatively and at plate removal. In addition, cartilage regeneration was evaluated at plate removal. We assessed changes in BTU for the medial and lateral compartment after OWHTO and the correlations between BTU of the medial compartment and all other parameters were analyzed.

RESULTS

Postoperatively, all outcome measures significantly improved: mean VAS 61.4 ± 18.3 to 9.5 ± 8.2, mean JOA score 65.1 ± 11.5 to 94.7 ± 6.0, mean OKS 29.4 ± 8.1 to 42.3 ± 4.1, mean KOOS 57.0 ± 14.3 to 83.7 ± 9.6, mean WBLR 22.8 ± 10.9 to 70.0 ± 9.4. Cartilage regeneration was observed in 53 knees (70.7%). BTU of the medial compartment significantly decreased after OWTHO, whereas no increased postoperative BTU was found in the lateral compartment. Postoperative BTU of the medial compartment significantly correlated with VAS, KOOS, and WBLR. No statistically significant associations were found between BTU and cartilage regeneration.

CONCLUSIONS

OWHTO significantly decreased BTU of the medial compartment, which correlated with knee pain and postoperative mechanical alignment. Unloading effects of OWHTO led to pain relief after surgery, regardless of cartilage regeneration.

Biplane opening wedge high tibial osteotomy with a distal tuberosity osteotomy, radiological and clinical analysis with minimum follow-up of 2 years

Background

High tibial osteotomy is an established and helpful treatment for unicompatimental osteoarthritis associated with varus deformity. However, asupratubercle high tibial osteotomy leads to a decrease in patellar height making the technique not suitable in case of concomitant patella baja. Moreover, this kind of osteotomy can change in situ forces at patellofemoral joint and the lateral patellar tilt. With the aim to widen the indication of high tibial osteotomy was proposed a biplane opening wedge high tibial osteotomy with a distal tuberosity osteotomy (B-OWHTO). This technique provide that the tibial tuberosity remains joined to the tibial metaphysis so as not to theoretically alter the patellar height. However, some Authors claim that BOWHTO could lead to an increase in tibial slope. The purpose of the present study was to assess the tibial slope, patella-femoral changes and axial correction as well as functional outcomes following a B-OWHTO.

Methods

Patients operated on with a B-OWHTO and a minimum 24 months of follow-up were included. The mechanical alignment of the lower limb, patellar height, lateral patellar tilt and posterior tibial slope were calculated preoperatively, immediately after surgery and at the 24-month follow-up. The clinical results were evaluated using the Lysholm, Kujala and Hospital for Special Surgery knee scores. The possible postoperative development of patellofemoral pain or radiologic patellofemoral alteration was also evaluated.

Results

Twenty-three patients were included with a mean follow-up of 33 months (range 27-41). The mechanical alignment of the lower limb shifted from a mean 9.3º ± 2.5 varus preoperatively to a mean 0.2º ± 2.2 valgus postoperatively. No changes in patellar height, lateral patellar tilt or in the posterior tibial slope were observed. The mean Lysholm and HSS scores improved from 68.3 ± 9.1 and 64.2 ± 5.2 preoperatively to 93.2 ± 2.1 and 94.1 ± 3.6 at final follow-up (p < 0.01). The mean Kujala score improved from 67.3 ± 9.8 to 86.4 ± 7.6 at final follow up (p < 0.01). No patients developed both radiological or clinical symptoms at patellofemoral joint.

Conclusions

Open wedge high tibial osteotomy with a dihedral L-cut distal and posterior to the tibial tubercle accurately corrected axial malalignment without any change at patella-femoral joint or any modification to the posterior tibial slope while providing improved knee function at short-term follow-up. The radiographic as well as the clinical results support the use of this technique to treat medial compartment knee osteoarthritis and varus malalignment in young and middle-aged patients with a normal-to-low patellar height.

Level of evidence

Case series with no comparison group, Level IV.

Can osteoarthritic patients with mild varus deformity be indicated for high tibial osteotomy?

BACKGROUND

Whether osteoarthritic patients with mild varus deformity can be indicated for high tibial osteotomy (HTO) is not established. We examined the preoperative characteristics and postoperative outcomes of HTO in patients with mild genu varum compared to patients with greater varus deformity.

METHODS

Seventy-one patients who underwent HTO were included in this retrospective study. Patients were divided into either mild varus (MV, mechanical femorotibial angle (mFTA) ≤4°, n = 31 (44%)) and greater varus (GV, mFTA >4°, n = 40 (56%)) groups. Preoperative characteristics on single photon emission computed tomography-computed tomography (SPECT-CT), magnetic resonance image and radiograph were evaluated. Alignment parameters and functional outcomes were compared pre- and postoperatively between the groups.

RESULTS

Preoperative characteristics were similar between the two groups, except the severity of arthritis and coronal alignment. There was no difference in the proportion of hot uptake in the medial compartment; medial meniscus posterior horn root tear, complex or radial tear; bone marrow edema. Full-thickness cartilage defect of medial compartment was more frequent and arthritis grade was also more severe in GV group. Coronal alignment of the MV group was corrected into more valgus than the GV group (4.5° vs. 2.8° in mFTA, P = 0.012). Pre- and postoperative Knee Society knee and function scores were also comparable in the two groups.

CONCLUSIONS

Mild varus patients are similar to greater varus patients regarding preoperative features and achieve the comparable functional outcome. A selected subset of osteoarthritic patients with mild varus deformity might be indicated for HTO.

LEVEL OF EVIDENCE

III (Retrospective comparative study).