Patellofemoral alignment and anterior knee pain after closing- and opening-wedge valgus 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.

The Influence of Tibial Tubercle-Sparing Slope-Reducing Osteotomy on Patellar Height in Patients Undergoing Revision ACL Reconstruction

BACKGROUND

A posterior tibial slope (PTS) >12° is an independent risk factor for anterior cruciate ligament (ACL) graft rupture, and a high tibial osteotomy (HTO) for slope correction can help avoid it. Management of patellar height is of major concern when performing HTO.

PURPOSE

To evaluate the effect of tibial tubercle-sparing anterior closing-wedge osteotomy on patellar height in revision ACL reconstruction (ACLR).

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who underwent arthroscopic revision ACLR combined with retro-tibial tubercle anterior closing-wedge HTO (ACW-HTO) between January 1, 2016, and March 31, 2021, were assessed for eligibility. Patellar height was measured on full weightbearing lateral radiographs according to the Insall-Salvati index (ISI) and Caton-Deschamps index (CDI) or frontal radiographs using the femoral patellar height index. The PTS was evaluated using the proximal anatomic axis of the tibia on standard short lateral radiographs. The delta (postoperative - preoperative) and the ratio (preoperative/postoperative) of the 3 patellar height indices and PTS were calculated. Preoperative and postoperative patellar heights were compared using independent t tests for each index. Also investigated was whether patients changed patellar height category (baja, normal, or alta) after slope osteotomy.

RESULTS

Among 475 revision ACLRs, 47 tibial tubercle-sparing ACW-HTOs were retained for analysis. No significant difference in patellar height was found between pre- and postoperative radiographs regardless of the index (preoperative - postoperative) (ISI: 1.0 ± 0.2 - 0.9 ± 0.2, P = .1729; CDI: 1.0 ± 0.2 - 1.0 ± 0.2, P = .4034; femoral patellar height index: 1.5 ± 0.2 - 1.5 ± 0.2; P = .5130). Fifteen patients (31.9%) exhibited a postoperative change in their patellar height category when measured by the ISI (6 moved up a category, 9 moved down one), and 18 patients (38.3%) changed category according to the CDI (10 moved up a category, 8 moved down one). No significant difference was found between pre- and postoperative patellar height among these patients (ISI: P = .2418; CDI: P = .3005).

CONCLUSION

Changes in patellar height ratio are common after tibial tubercle-sparing ACW-HTO in patients undergoing revision ACLR. The clinical effect of these changes is unknown, and further study is needed to investigate whether they may result in patellofemoral symptoms.

High rates of outliers in computer-assisted high tibial osteotomy with excellent mid-term outcomes

PURPOSE

The primary aim was to evaluate the accuracy of navigation in opening wedge high tibial osteotomy (HTO). The secondary aim was to examine mid-term outcomes after HTO.

METHODS

Inclusion criteria were patients with medial compartment knee osteoarthritis who underwent computer-assisted HTOs. Mechanical axis (MA), percentage MA (%MA), and change in posterior tibial slope (ΔPTS) were displayed on the navigation screen. Radiographic examinations included hip-knee-ankle (HKA) angle, medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), and PTS. Preoperative and 5 weeks postoperative standing radiographs of the whole lower extremity and knee were used. Clinical evaluations were performed using American Knee Society knee score and function score both preoperatively and at last follow-up. Radiographic evaluations were performed by orthopedic surgeons. Intraoperative navigation after osteotomy and postoperative standing radiograph were compared. MA (HKA), %MA, and ΔPTS were compared. Outliers were defined as > 3° in MA, > 10% in %MA, and > 10° in ΔPTS. Outlier and non-outlier groups were compared. The rate of conversion to arthroplasty was examined.

RESULTS

This study involved 38 patients (44 knees) and last follow-up was at a mean of 5 years (range, 1-9 years). Mean American Knee Society knee score and function score improved significantly from 59 to 69 preoperatively to 95 and 85 at last follow-up, respectively. Absolute values of mean errors for MA, %MA, and ΔPTS were 2.1°, 9.3%, 1.2°, respectively. Outlier rates were 18% in MA, 39% in %MA, and 5% in ΔPTS. No significant factors were found in MA and ΔPTS. In %MA, preoperative JLCA was significantly higher in the outlier group compared to the non-outlier group. No knees underwent conversion to total knee arthroplasty. No differences in outcomes were found between outlier and non-outlier groups.

CONCLUSION

Although rates of outlier values in computer-assisted opening wedge HTO were high, mid-term outcomes were excellent.

LEVEL OF EVIDENCE

IV.

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.

Medially and distally inserted tuberosity screw fixation of the osteotomized tubercle is safe and effective in retro-tubercular bi-planar opening-wedge high tibial osteotomy

PURPOSE

The purpose of this study was to develop a safe and effective method of inserting one tuberosity screw and to determine whether retro-tubercular (RT)-Open-wedge high tibial osteotomy (OWHTO) with tuberosity screw fixation can be conducted to overcome the problem of osteotomized tubercle and produce favorable outcomes compared to RT-OWHTO without tuberosity screw fixation.

METHODS

From 2018 to 2020, patients who underwent bi-planar RT-OWHTO were allocated as two groups (RT-OWHTO without tuberosity screw fixation as group I and with screw fixation as group II). Computed tomography (CT) was used to analyze osteotomy configurations such as RT gap and tip distance, and union of the main and second plane osteotomy sites. The RT gap distance was measured as the length of the osteotomy gap. The RT tip distance was measured as the length of the gap at the tip of the tibial tubercle. Post-operative complications were analyzed also. To evaluate the neurovascular (NV) approximity of screw fixation group, the pre-operative magnetic resonance imaging (MRI) images were referenced on the post-operative CT for the assessment of the safe zone.

RESULTS

In total, 44 knees in group I and 46 knees in group II were enrolled. The RT gap distance (2.58 ± 0.69 mm vs. 0.57 ± 0.57 mm; p < .001) and RT tip distance (4.31 ± 1.60 mm vs. 1.48 ± 1.42 mm; p < .001) were significantly larger in group I than in group II. The sum of union grade in the second plane osteotomy site (17.93 ± 2.18 points vs. 22.24 ± 2.57 points; p < .001) was statistically different between two groups at three months post operatively. Post-operative tuberosity prominence occurred in five knees only in group I (p = 0.025), although tibial tuberosity fracture developed in seven cases in group II compared with two cases in group I with no statistical significance. NV was safe when the screw was inserted medially.

CONCLUSION

RT-OWTHO with one-screw fixation for the tuberosity was effective in terms of tuberosity prominence and the union of the second plane osteotomy site. However, it also produced another problem, such as tuberosity fracture. In addition, a tuberosity screw was safe when it was inserted in the medial-distal direction.

LEVEL OF EVIDENCE

Cohort study; level III.

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.

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.

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.

Retro-Tubercle Biplanar Opening Wedge High Tibial Osteotomy Is Favorable for the Patellofemoral Joint But Not for the Osteotomized Tubercle Itself Compared With Supra-Tubercle Osteotomy

PURPOSE

To identify whether retro-tubercle opening-wedge high tibial osteotomy (RT-OWHTO) produces more favorable radiographic outcomes on patellofemoral joint alignment and clinical outcomes than supra-tubercle opening-wedge high tibial osteotomy (ST-OWHTO).

METHODS

From January 2017 to July 2018, patients who underwent biplanar OWHTO were allocated to 1 of 2 groups (ST-OWHTO and RT-OWHTO). Plain radiographs and computed tomography were used to analyze patellofemoral alignment and other radiologic parameters representing osteotomy configurations. Clinical outcomes were assessed using American Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index.

RESULTS

In total, 50 knees that underwent ST-OWHTO and 44 knees that underwent RT-OWHTO were enrolled. Patellar height was significantly decreased only after ST-OWHTO (Caton-Deschamps ratio: P = .007; Blackburne-Peel ratio: P = .012). Patellar tilt angle was decreased in both groups (P = .009 and .004, respectively). Postoperative posterior tibial slope (PTS) (P = .013), PTS (Δ) (P < .001), retro-tuberosity gap distance (P = .001), and retro-tuberosity tip distance (P = .001) were significantly larger in RT-OWHTO. Retro-tuberosity tip distance was significantly correlated with retro-tuberosity gap distance (P = .002), thickness of second plane osteotomy fragment (P = .027), and anterior osteotomy ratio (P = .031) in ST-OWHTO. In RT-OWHTO, it was significantly correlated with PTS (△) (P < .001), retro-tuberosity gap distance (P < .001), and sagittal angle of bi-planar osteotomy (P = .005). There were 2 cases of tibial tuberosity fracture, 9 cases of delayed union on second plane osteotomy and 5 cases of tuberosity protrusion in RT-OWHTO.

CONCLUSIONS

Although the RT-OWHTO technique maintains patellofemoral joint alignment, no difference in clinical outcome was detected. The RT-OWHTO has increased risk of tuberosity fracture, delayed union, and prominent tibial tuberosity. The surgeon should consider these negative aspects of the technique and consider adjusting additional stabilization.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

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.

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.

Biomechanical effect of a lateral hinge fracture for a medial opening wedge high tibial osteotomy: finite element study

BACKGROUND

This study aimed to investigate the biomechanical effect on the Takeuchi classification of lateral hinge fracture (LHF) after an opening wedge high tibial osteotomy (HTO).

METHODS

We performed an FE simulation for type I, type II, and type III in accordance with the Takeuchi classification. The stresses on the bone and plate, wedge micromotion, and forces on ligaments were evaluated to investigate stress-shielding effect, plate stability, and biomechanical change, respectively, in three different types of LHF HTO and with the HTO without LHF model (non-LHF) models.

RESULTS

The greatest stress-shielding effect and wedge micromotion were observed in type II LHF (distal portion fracture). The type II and type III (lateral plateau fracture) models exhibited a reduction in ACL force and an increase in PCL force compared with the HTO without LHF model. However, the type I (osteotomy line fracture) and HTO without LHF models did not exhibit a significant biomechanical effect. This study demonstrates that Takeuchi type II and type III LHF models provide unstable structures compared with the type I and HTO without LHF models.

CONCLUSIONS

HTO should be performed while considering a medial opening wedge HTO to avoid a type II and type III LHF as a potential complication.

A novel device for greater precision and safety in open-wedge high tibial osteotomy: cadaveric study

INTRODUCTION

The complications of the open-wedge osteotomy technique (slope, hypo- and hypercorrection and fractures) are related to difficulties in the control of the open-wedge angle during surgery.

MATERIALS AND METHODS

In this cadaveric study, we evaluated the safety and precision of a novel system, the Realignment High Control System (RHC), in the correction of knee mechanical axis and slope. The RHC has a fixation plate coupled to a dynamic device that opens the osteotomy continuously, allowing plate fixation before osteotomy wedge opening.

RESULTS

All procedures were easily performed, with no fractures. The openings equaled the indicated by the navigation system for 7.5° and 10°, and for 5°, there was a statistically, although not clinically significant, difference of 0.6°. The slope shown by the RHC setting and in the navigation system was significantly different for the 10° setting only, with a mean difference of 0.563°.

CONCLUSIONS

RHC facilitates the surgical technique of high tibial osteotomy, with gradual wedge opening, precise correction of the mechanical axis, and appropriate control of the tibial slope, even with larger openings.

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.

Radiographic changes and clinical outcomes after open and closed wedge high tibial osteotomy: a systematic review and meta-analysis

BACKGROUND

The purpose of this meta-analysis is to examine changes in radiological variables and clinical outcomes between open and closed wedge high tibial osteotomy (OWHTO and CWHTO, respectively), which have ongoing controversial issues in numerous quantitative clinical studies.

METHODS

PubMed, Embase, and the Cochrane Library were systematically searched for suitable controlled trials between Jan 1, 1999, and Feb 2, 2018. The inclusion criteria included studies written in English, studies with a level of evidence of I-IV, and studies presenting comparisons between OWHTO and CWHTO. The main clinical and radiographic results were extracted and pooled using Stata 12.0.

RESULTS

After searching for and screening trials, 28 trials involving 2840 knees were eligible for the meta-analysis. After OWHTO or CWHTO, clinical scores, including the American Knee Society Score, Hospital for Special Surgery Knee Score, Lysholm score, and Visual Analog Scale pain score, improved (p < 0.05), but the range of motion was unchanged (p > 0.05). The anatomical femorotibial angle (SMD 0.04, 95% CI - 0.66 to 0.74) and hip-knee-ankle angle (SMD 0.11, 95% CI - 0.11 to 0.33) data suggested that the OWHTO and CWHTO groups were similar in function of correction. Posterior tibial slope increased (SMD - 0.71, 95% CI - 1.04 to - 0.37) after OWHTO but decreased (SMD 0.72, 95% CI 0.35 to 1.08) after CWHTO. OWHTO decreased patellar height (p < 0.05), while patellar height did not change significantly after CWHTO (p > 0.05).

CONCLUSION

This meta-analysis indicates that compared with CWHTO, OWHTO increases the posterior slope, decreases the patellar height, and provides a similar accuracy of correction; however, CWHTO leads to a decreased posterior slope and an unchanged patellar height. Therefore, programs should be personalized and customized for the specific situation of each patient.

Predictive Factors for Patellofemoral Degenerative Progression After Opening-Wedge High Tibial Osteotomy

PURPOSE

To identify risk factors for patellofemoral degenerative progression after opening-wedge high tibial osteotomy (HTO) and to investigate the effect of patellofemoral degeneration on the patellofemoral specific patient-reported outcomes.

METHODS

Between March 2010 and June 2016, 94 knees (86 patients) underwent hardware removal with second-look arthroscopy at 21.4 months after opening-wedge HTO with first-look arthroscopy (mean follow-up duration, 49.8 months). Predictive factors for patellofemoral degeneration, including demographics, preoperative and postoperative mechanical axis (MA) of the lower limb (positive and negative MA indicating varus and valgus, respectively), tibial slope, and modified Blackburne-Peel ratio, were evaluated. Patients were divided into the progression and nonprogression groups according to their patellofemoral degenerative progression from first to second arthroscopy. Clinical outcomes, including the Kujala score and Knee Injury and Osteoarthritis Outcome Score, and radiographic outcomes were compared between the 2 groups.

RESULTS

Postoperative MA (adjusted odd ratio, 0.62; P < .001) was the most significant predictive factor for progressive change in the patellofemoral joint (R_n² = 0.31). Twenty-eight knees (30%) showed patellofemoral degenerative progression. Mean postoperative Kujala score (progression group 60.5 vs nonprogression group, 72.3; P = .005) and Knee Injury and Osteoarthritis Outcome Score scales (except for the symptom subscale) were lower in the progression group. Postoperative MA was significantly more corrected in the progression group (progression group -5.1° ± 2.7° vs nonprogression group -2.4° ± 2.3°; P < .001).

CONCLUSIONS

Postoperative MA, which might be related to overcorrection, is correlated with patellofemoral degenerative progression after opening-wedge HTO. Patients with patellofemoral degenerative progression showed inferior patient-reported outcomes.

LEVEL OF EVIDENCE

Level IV, case series with subgroup analysis.

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

PURPOSE

To identify parameters associated with deterioration of patellofemoral (PF) cartilage after open-wedge high tibial osteotomy (OWHTO) and determine predictive values. It was hypothesized that cartilage injuries in PF joints would progress after OWHTO in patients who need a large alignment correction.

METHODS

Fifty-two knees in 47 patients who underwent bi-planer OWHTO for the treatment of medial compartment osteoarthritis from 2012 to 2017 and received a second-look arthroscopy at the time of plate removal (mean 14 months post-OWHTO) were assessed. Clinical outcomes were evaluated by the Knee Society Scores. Cartilage status in PF joints were evaluated arthroscopically using the International Cartilage Repair Society (ICRS) grading system. Patients were divided into two groups and patients who had progressed PF cartilage injury (progressed group) were compared with those who did not have progressed PF cartilage injuries (non-progressed group) using various parameters. The relationships between medial opening gap or change in the medial proximal tibial angle (ΔmPTA) and progression of PF cartilage injuries were examined by receiver operating characteristic (ROC) curve analysis.

RESULTS

The mean Knee Society Scores were significantly improved after surgery (P < 0.01). The grades for the patella and trochlea progressed in 12 (23.0%) and 16 knees (30.8%), respectively. The mean preoperative hip-knee-ankle (HKA) angle, mechanical axis, and mPTA in the progressed group were significantly smaller than those in the non-progressed group (P < 0.01). The mean medial opening gap and ΔmPTA in the progressed group were significantly larger than those in the non-progressed group (P < 0.01). ROC curve analysis showed that the cut-off values of the medial opening gap and ΔmPTA for progression of PF cartilage injuries were 13 mm and 9°, respectively. Progression of PF cartilage injuries was more frequently observed in knees with a medial opening gap ≥ 13 mm (P = 0.019, odds ratio = 4.60) or a ΔmPTA ≥ 9° (P = 0.003, odds ratio 6.93) than knees with those of < 13 mm or 9°, respectively.

CONCLUSIONS

Cartilage injuries in PF joints tended to progress after OWHTO in patients with medial opening gap ≥ 13 mm or ΔmPTA ≥ 9°. If medial opening gap is ≥ 13 mm or ΔmPTA is ≥ 9° in planning for OWHTO, other type of surgery may need to be considered to avoid early progression of PF cartilage injuries.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Patella height is not altered by descending medial open-wedge high tibial osteotomy (HTO) compared to ascending HTO

PURPOSE

The primary purpose of the study was to gain insight into geometric changes of the patellar height (PH) and posterior tibial slope (PTS) after a biplanar ascending medial open-wedge high tibial osteotomy (HTO) compared to biplanar descending medial open-wedge HTO in patients with genu varum.

METHODS

Sixty-four patients (mean age 45.2 ± 8.7 years, females n = 24, males n = 40) with varus malalignment and medial gonarthrosis were retrospectively studied. Patients received either a biplanar ascending or descending medial open-wedge HTO. Radiographic analysis included the assessment of standing total leg axis, PH, and PTS prior to and after surgery.

RESULTS

In the ascending HTO group, PH decreased significantly by 4.0% (p = 0.037, Caton-Deschamps index) after an average leg axis valgus-producing correction of 7.1° ± 2.8°. In the descending HTO group, with an average leg axis correction of 7.0° ± 3.7°, there were no significant PH changes. There were no significant differences between the ascending and descending HTO groups regarding PTS or leg axis. The mean post-operative leg axis between ascending (1.6° ± 1.9°) and descending HTO (1.9° ± 2.4°) was not significantly different.

CONCLUSION

Compared to the biplanar ascending medial open-wedge HTO, the descending HTO did not influence patella height or increase the posterior tibial slope. In order to respect patellofemoral and slope-related knee kinematics, a biplanar descending medial open-wedge HTO has proven useful to control patella height and posterior tibial slope. These findings underscore the importance of the preoperative patella height assessment in the osteotomy planning and subsequent choice of the biplanar osteotomy direction.

LEVEL OF EVIDENCE

IV.

The correlation of sagittal osteotomy inclination and the anteroposterior translation in medial open-wedge high tibial osteotomy-one of the causes affecting the patellofemoral joint?

PURPOSE

For opening-wedge high tibial osteotomy, previous studies have shown that most osteotomies were anterior-inclined. The purpose of this study was to determine the effect of sagittal osteotomy inclination on the anteroposterior translation of osteomized fragments and discuss its possible impact on the patellofemoral joint.

METHODS

We retrospectively measured the angle between the joint line and the sagittal osteotomy line. We also evaluated the anteroposterior translation of osteomized fragments by measuring the distance from the most posterior point of the tibial plateau to the tibial tuberosity and the anterior cortical line. Correlation between the sagittal osteotomy inclination and the anteroposterior translation of fragments was analyzed.

RESULTS

The mean sagittal osteotomy inclination was 6.3 ± 8.4° anteriorly to the joint line and 82% of osteotomies were anterior-inclined. The anteroposterior translation of the osteomized fragments was moderately correlated to the sagittal inclination. Anterior-inclined osteotomy tends to result in the anterior translation of the proximal fragment.

CONCLUSION

High rates of anterior-inclined osteotomy have been described previously as well as in this study. Anterior-inclined osteotomy tends to result in the anterior translation of the proximal fragment. This may result in increased vertical vector force onto the patellofemoral joint, which further accelerates patellofemoral joint degeneration. Therefore, surgeons should attempt to perform parallel osteotomy or avoid anterior displacement of the proximal fragment if there is concern of anterior-inclined osteotomy.

Diagnostic Value of Computed Tomography and Risk Factors for Lateral Hinge Fracture in the Open Wedge High Tibial Osteotomy

PURPOSE

The purposes of this study were to evaluate (1) the disparity of detection of lateral hinge fracture (LHF) between postoperative simple radiography and high-resolution computed tomography (CT) and affecting factors of LHF and (2) whether generally recommended postoperative rehabilitation protocols are appropriate according to the type of LHF.

METHODS

From 2014 to 2015, patients who underwent primary open wedge high tibial osteotomy (OWHTO) for isolated medial compartment osteoarthritis of the knee joint were retrospectively enrolled. The patients with minimum 1-year follow-up were included. The incidence of LHF after OWHTO based on simple radiographs was compared with its incidence based on CT scans. In the stable type of LHF and the non-LHF group, early weight bearing was encouraged immediately after OWHTO. In unstable LHF (types II and III), weight bearing was delayed until 2 weeks postoperatively.

RESULTS

Twenty-three cases (24.5%) of LHF after 94 OWHTOs were detected (15 cases on simple radiographs, 8 cases on CT scan). The coronal osteotomy slope and the osteotomy gap were significantly larger in the LHF group than in the non-LHF group (coronal osteotomy slope, 20.3° ± 5.1° vs 16.7° ± 4.2°, P = .001; anterior osteotomy gap, 7.9 mm ± 2.1 mm vs 6.7 mm ± 1.8 mm, P = .008; posterior osteotomy gap, 12.7 mm ± 3.7 mm vs 11.2 mm ± 3.2 mm, P = .048). The correction loss of the hip-knee-ankle angle and the medial proximal tibial angle in the LHF group was significantly larger than those in the non-LHF group (1.3° ± 1.8° vs 0.4° ± 1.4°, P < .001; 1.3° ± 1.1° vs 0.7° ± 0.9°, P = .009, respectively).

CONCLUSIONS

Further evaluation with CT scanning is highly valuable immediately after all OWHTO because of its higher detection rate (24.5%) of LHF compared with simple radiographs (16%). In addition, the coronal osteotomy slope was steeper and the opening gap was larger in the LHF group than in the non-LHF group. Finally, the LHF should be managed conservatively in order to prevent postoperative correction loss.

LEVEL OF EVIDENCE

Level III, case-control study.

Patellofemoral Osteoarthritis Progression and Alignment Changes after Open-Wedge High Tibial Osteotomy Do Not Affect Clinical Outcomes at Mid-term Follow-up

PURPOSE

To evaluate the clinical and radiological outcomes of open-wedge high tibial osteotomy (OWHTO) with respect to the patellofemoral joint and to assess whether patellofemoral osteoarthritis (OA) progression and alignment changes after OWHTO affect clinical outcomes.

METHODS

Inclusion criteria were consecutive patients who underwent OWHTO from March 2005 to September 2013. Exclusion criteria were loss to follow-up within 2 years and absence of second-look arthroscopy findings at the time of plate removal. The clinical parameters, including anterior knee pain while climbing stairs, Japanese Orthopedic Association score, and Oxford Knee Score, were evaluated. Radiological outcomes, including weight-bearing line ratio, modified Blackburne-Peel ratio, posterior tibial slope, tilting angle, lateral shift ratio, and patellofemoral OA (Kellgren-Lawrence grade), were evaluated preoperatively and at the final follow-up. Cartilage status (International Cartilage Repair Society grade) was evaluated at the initial HTO and at plate removal.

RESULTS

Fifty-three patients (60 knees) were included in this study. The mean follow-up was 58.2 ± 22.4 months. Two knees (3%) presented with mild anterior knee pain after OWHTO. The mean Japanese Orthopedic Association score (66.9 ± 11.2 to 91.2 ± 9.7) significantly improved (P < .001), and the mean Oxford Knee Score at the final follow-up was 42.0 ± 5.3. The mean modified Blackburne-Peel ratio (0.9 ± 0.1 to 0.7 ± 0.1, P < .001) and tilting angle (6.8 ± 3.7 to 5.6 ± 3.4, P = .033) significantly decreased after OWHTO, whereas no significant changes in posterior tibial slope (P = .511) and lateral shift ratio (P = .522) were observed. Radiologically, patellofemoral OA had progressed in 15 knees (27%), and arthroscopically patellofemoral cartilage degeneration had progressed in 27 knees (45%). However, there was no significant correlation between changes in patellofemoral alignment and clinical outcomes.

CONCLUSIONS

Changes in patellofemoral alignment and patellofemoral OA progression did not affect the clinical outcomes of OWHTO at mid-term follow-up.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Robotic device-assisted knee extension training during the early postoperative period after opening wedge high tibial osteotomy: a case report

BACKGROUND

Maintenance or restoration of a good range of motion of the knee is one of the most important outcomes following knee surgery. According to previous studies, opening wedge high tibial osteotomy enables better recovery of range of motion in knee flexion than that achievable after total knee arthroplasty or unicompartmental knee arthroplasty. However, few reports provide a detailed description of the postoperative recovery of knee extension range of motion after opening wedge high tibial osteotomy. We describe our experience with a knee extension training program using a single-joint hybrid assistive limb device (HAL-SJ; Cyberdyne Inc., Tsukuba, Japan) during the acute recovery phase after opening wedge high tibial osteotomy. The HAL-SJ is a wearable robotic device that facilitates voluntary control of knee joint motion.

CASE PRESENTATION

A 67-year-old Japanese woman who underwent opening wedge high tibial osteotomy for spontaneous osteonecrosis of the left medial femoral condyle received HAL-SJ-based knee extension training postoperatively. Our experience with this patient revealed that knee extension training with the HAL-SJ during the acute phase following opening wedge high tibial osteotomy is feasible. Furthermore, the patient's knee extension range of motion improved to values similar to those seen during the preoperative stage, and her flexion range of motion was improved at 3 months after the surgery.

CONCLUSIONS

HAL-SJ-based knee extension training could be used as a novel post-opening wedge high tibial osteotomy rehabilitation modality. Further exploration of individualized optimal settings of the HAL-SJ is required to improve its safety and efficacy.

Medial Open-Wedge High Tibial Osteotomy May Adversely Affect the Patellofemoral Joint

PURPOSE

To evaluate 2-stage arthroscopic findings of the patellofemoral joint before and after medial open-wedge high tibial osteotomy (HTO) and verify whether the patellofemoral joint would be influenced by medial open-wedge HTO.

METHODS

We prospectively reviewed 114 cases of medial open-wedge HTO for the treatment of osteoarthritis with a varus knee. First-look arthroscopy was performed during HTO. The mean age at the time of HTO was 56.34 ± 5.4 years (range, 40-69 years). Second-look arthroscopy was performed concomitantly with plate removal at an average of 26.1 ± 6.0 months (range, 21.6-32.0 months) after HTO. We assessed the patellofemoral joint using the International Cartilage Repair Society (ICRS) grading system by first- and second-look arthroscopy and compared it before and after HTO. Postoperative anterior knee pain was also evaluated.

RESULTS

Compared with first-look findings, second-look arthroscopic ICRS grading was changed as follows: In terms of the patella, 89 cases (78.1%) were not progressed whereas 25 cases (21.9%) were progressed. In terms of the femoral trochlea, 67 cases (58.8%) were not progressed whereas 47 cases (41.2%) were progressed. There was significant progression of the ICRS grade of the patella (P = .001) and femoral trochlea (P < .001) compared with first-look arthroscopic findings. The incidence of postoperative anterior knee pain was 11.4% (13 cases), and it was related to the ICRS grade of the patellofemoral joint at the time of second-look arthroscopy (P < .001 for patella and P < .001 for trochlea).

CONCLUSIONS

This study showed that the patellofemoral joint might be adversely affected by medial open-wedge HTO. Although the incidence of postoperative anterior knee pain was low, it was clinically correlated with patellofemoral arthritis.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Open-wedge high tibial osteotomy versus unicompartmental knee arthroplasty: no difference in progression of patellofemoral joint arthritis

PURPOSE

The purpose of this retrospective comparative study was to evaluate and compare, radiographically and clinically, progression of osteoarthritis (OA) in the patellofemoral (PF) compartment after open-wedge high tibial osteotomy (OWHTO), and unicompartmental knee arthroplasty (UKA) over a minimum follow-up of 5 years.

METHODS

In this study, 42 knees in an OWHTO group were compared with 59 knees in a UKA group in terms of radiographic parameters, such as the grading system for OA progression in the PF compartment, and clinical parameters, such as the PF pain and function scores over a minimum follow-up of 5 years.

RESULTS

There was no significant difference of OA progression in the PF compartment between the two groups on knee radiography. Compared with the preoperative grades, the UKA group showed significant progression of OA in the medial PF compartment at the final follow-up, whereas the medial PF compartment showed significant stepwise progression by only one grade when compared to the OWHTO group. The PF pain and function scores showed no statistical differences between the two groups at the final follow-up, regardless of OA progression.

CONCLUSIONS

There was no significant difference between OWHTO and UKA in terms of progression of OA in the PF compartment or deterioration of PF function score over a minimum follow-up of 5 years. However, the medial PF compartment of the UKA group was minimal, and worsened or progressed by only one grade.

LEVEL OF EVIDENCE

III.

Comparison of clinical and radiological outcomes between opening-wedge and closing-wedge high tibial osteotomy: A comprehensive meta-analysis

High tibial osteotomy (HTO) has been widely used for clinical treatment of osteoarthritis of the medial compartment of the knee, and both opening-wedge and closing-wedge HTO are the most commonly used methods. However, it remains unclear which technique has better clinical and radiological outcomes in practice. To systematically evaluate this issue, we conducted a comprehensive meta-analysis by pooling all available data for the opening-wedge HTO and closing-wedge HTO techniques from the electronic databases including PubMed, Embase, Wed of Science and Cochrane Library. A total of 22 studies encompassing 2582 cases were finally enrolled in the meta-analysis. There was no significant difference regarding surgery time, duration of hospitalization, knee pain VAS, Lysholm score and HSS knee score (clinical outcomes) between the opening-wedge and closing-wedge HTO groups (P > 0.05). However, the opening-wedge HTO group showed wider range of motion than the closing-wedge HTO group (P = 0.003). Moreover, as for Hip-Knee-Ankle angle and mean angle of correction, no significant difference was observed between the opening-wedge and closing-wedge HTO groups (P > 0.05), while the opening-wedge HTO group showed greater posterior tibial slope angle (P < 0.001) and lesser patellar height than the closing-wedge HTO group (P < 0.001). On light of the above analysis, we believe that individualized surgical approach should be introduced based on the clinical characteristics of each patient.

Change in Posterior Tibial Slope After Open-Wedge and Closed-Wedge High Tibial Osteotomy: A Meta-analysis

BACKGROUND

It is unclear whether open- or closed-wedge high tibial osteotomy (HTO) results in significant changes in posterior tibial slope, with no consensus on the magnitude of such changes. Furthermore, methods of measuring posterior tibial slope differ among studies. This meta-analysis was therefore designed to evaluate whether posterior tibial slope increases after open-wedge HTO and decreases after closed-wedge HTO and to quantify the magnitudes of the slope changes after open- and closed-wedge HTO using various methods of measuring posterior tibial slope.

HYPOTHESIS

Posterior tibial slope increases after open-wedge and decreases after closed-wedge HTO. The magnitude of change is similar for the 2 methods, and the value obtained for posterior tibial slope change is affected by the method of measurement.

STUDY DESIGN

Meta-analysis.

METHODS

Multiple comprehensive databases, including MEDLINE, EMBASE, the Cochrane Library, and KoreaMed, were searched for studies that evaluated the posterior slope of the proximal tibia in patients who had undergone open- and/or closed-wedge HTO. Studies were included that compared pre- and postoperative posterior tibial slopes, regardless of measurement method, including anterior and posterior tibial cortex or tibial shaft axis as a reference line, in patients who underwent open- or closed-wedge HTO. The quality of each included study was appraised with the Newcastle-Ottawa Scale.

RESULTS

Twenty-seven studies were included in the meta-analysis. Pooled data, which included subgroups of 3 methods, showed that posterior tibial slope increased 2.02° (95% CI, 2.66° to 1.38°; P = .005) after open-wedge HTO and decreased 2.35° (95% CI, 1.38° to 3.32°; P < .001) after closed-wedge HTO.

CONCLUSION

This meta-analysis confirmed that posterior tibial slope increased after open-wedge HTO and decreased after closed-wedge HTO when the results of a variety of measurement methods were pooled. The magnitude of change after open- and closed-wedge HTO was similar and small (approximately 2°), suggesting that both osteotomy techniques may have little effect on the biomechanics of the cruciate ligaments.

Changes in Patellar Height After Opening Wedge and Closing Wedge High Tibial Osteotomy: A Meta-analysis

PURPOSE

To test that patellar height decreases (patellar baja) after opening wedge high tibial osteotomy (HTO) and increases (patellar alta) after closing wedge HTO. In addition, this meta-analysis evaluated whether the method of measuring patellar height affected the change in patellar height after opening and closing HTO.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, all studies comparing pre- and postoperative patellar height using various indices, including the Insall-Salvati index (ISI), Blackburne-Peel index, and Caton Deschamps index, in patients who underwent opening or closing wedge HTO were included. The main outcome of this meta-analysis, mean change in patellar height from before to after surgery, was analyzed with a random effects model. Publication bias was evaluated using funnel plots and Egger's test.

RESULTS

Twenty-three studies were included in the meta-analysis. Pooled data, including subgroups of the 3 measurement methods, showed that patellar height decreased 7% after opening wedge HTO (95% confidence interval [CI]: 0.05 to 0.10; P < .001), except when patellar height was assessed by ISI (95% CI: -0.02 to 0.06; P = .34), but that there was no change in patellar height after closing HTO (95% CI: -0.01 to 0.04; P = .29).

CONCLUSIONS

The patellar height decreased after opening wedge HTO, except when assessed by ISI. In contrast, patellar height was unchanged after closing wedge HTO, regardless of the measurement method.

LEVEL OF EVIDENCE

Level II, meta-analysis of Level I and II studies.

High tibial osteotomy for the treatment of medial osteoarthritis of the knee with new iBalance system: 2 years of follow-up

BACKGROUND

A new system for performing open-wedge high tibial osteotomy (HTO), the iBalance HTO System-Arthrex, has been recently developed in order to make the surgery more reproducible and safe. The aim of this study was to determine the short-term outcomes of the iBalance technique in medial compartment osteoarthritis and varus malalignment of the knee.

METHODS

Fifteen patients with a mean age of 50.7 years (SD 5.09), affected by symptomatic varus knee, with medial compartment osteoarthritis (1-2 Ahlbäck degree), were treated with iBalance HTO between July 2011 and February 2012 and evaluated retrospectively. Patients were assessed against the following benchmarks: subjective International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and VAS for pain and Tegner scores, along with X-rays and MRI, before surgery and after a 2-year follow-up.

RESULTS

No severe intraoperative complications or implant failures occurred. The mean preoperative scores were as follows: subjective IKDC 66.8 (SD 1.18), KOOS 61.3 (SD 0.86), Vas for pain 8.6 (SD 1.72) and Tegner 4.1 (SD 2.06), while at follow-up the scores were 73.6 (SD 1.01), 88.1 (SD 1.23), 2.9 (SD 2.35) and 3.1 (SD 1.83), respectively. Correction ranged between 3° and 8°. All patients showed complete articular recovery, no loss of correction, no substantial variation in A/P slope and no hardware problems.

CONCLUSIONS

iBalance proved to be effective and safe and produced good overall results. Consolidation and osseointegration of the system took place rapidly, while recovery was precocious, comparable with traditional methods and with no severe complications.

LEVEL OF EVIDENCE

Case series, Level IV.

Better clinical results after closed- compared to open-wedge high tibial osteotomy in patients with medial knee osteoarthritis and varus leg alignment

PURPOSE

Studies comparing mid- or long-term outcomes of open- and closed-wedge high tibial osteotomy are limited. Here, the midterm survival rate and clinical and radiographic outcomes were compared for these two techniques. The study hypothesis, based on short-term follow-up, was that after midterm follow-up, the two techniques would not differ.

METHODS

A prospective follow-up study was conducted for a previously reported randomized controlled trial of an original 50 patients (25 open-wedge osteotomy and 25 closed-wedge osteotomy) with medial knee osteoarthritis and a varus leg alignment. We analyzed patients without knee arthroplasty (mean age 48.7 years, SD 8.0) for clinical and radiographic follow-up.

RESULTS

Five patients in each group had undergone conversion to a total knee arthroplasty or unicompartmental knee arthroplasty, leaving 19 patients for analysis in each group. At 7.9 years of follow-up (range 7-9 years), survival did not differ significantly between groups (open-wedge group 81.3% [95% confidence interval (CI) 75.2-100], closed-wedge group 82.0% [95% CI 66.7-100]). At final follow-up, total Dutch Western Ontario and McMaster Universities Arthritis (WOMAC), Knee Society Score, and visual analog scale (VAS) pain did not differ between groups. However, the results were significantly better in the closed-wedge group for VAS satisfaction and WOMAC pain and stiffness compared to the open-wedge group. Radiographic evaluation did not differ between groups for any outcome at final follow-up.

CONCLUSION

After a mean follow-up of 7.9 years, patients undergoing a closed-wedge osteotomy had favorable clinical results compared to those who underwent an open-wedge osteotomy.

LEVEL OF EVIDENCE

II.

Changes in patellofemoral alignment do not cause clinical impact after open-wedge high tibial osteotomy

PURPOSE

The objectives of this study were (1) to evaluate the clinical and radiologic outcomes of open-wedge high tibial osteotomy focusing on patellofemoral alignment and (2) to search for correlation between variables and patellofemoral malalignment.

METHODS

A total of 46 knees (46 patients) from 32 females and 14 males who underwent open-wedge high tibial osteotomy were included in this retrospective case series. Outcomes were evaluated using clinical scales and radiologic parameters at the last follow-up. Pre-operative and final follow-up values were compared for the outcome analysis. For the focused analysis of the patellofemoral joint, correlation analyses between patellofemoral variables and pre- and post-operative weight-bearing line (WBL), clinical score, posterior slope, Blackburn Peel ratio, lateral patellar tilt, lateral patellar shift, and congruence angle were performed.

RESULTS

The minimum follow-up period was 2 years and median follow-up period was 44 months (range 24-88 months). The percentage of weight-bearing line was shifted from 17.2 ± 11.1 to 56.7 ± 12.7%, and it was statistically significant (p < 0.01). Regarding the clinical results, statistical significance was observed using all scores (p < 0.01). In the radiologic evaluation, patellar descent was observed with statistical significance (p < 0.01). Last follow-up lateral patellar tilt was decreased with statistical significance (p < 0.01). In correlation analysis between variables of patellofemoral malalignment, the pre-operative weight-bearing line showed an association with the change in lateral patellar tilt and lateral patellar shift (correlation coefficient: 0.3).

CONCLUSION

After open-wedge high tibial osteotomy, clinical results showed improvement, compared to pre-operative values. The patellar tilt and lateral patellar shift were not changed; however, descent of the patella was observed. Therefore, mild patellofemoral problems should not be a contraindication of the open-wedge high tibial osteotomy.

LEVEL OF EVIDENCE

Case series, Level IV.

The Meniscus-Deficient Knee: Biomechanics, Evaluation, and Treatment Options

Meniscal tears are the most common knee injury, and partial meniscectomies are the most common orthopaedic surgical procedure. The injured meniscus has an impaired ability to distribute load and resist tibial translation. Partial or complete loss of the meniscus promotes early development of chondromalacia and osteoarthritis. The primary goal of treatment for meniscus-deficient knees is to provide symptomatic relief, ideally to delay advanced joint space narrowing, and ultimately, joint replacement. Surgical treatments, including meniscal allograft transplantation (MAT), high tibial osteotomy (HTO), and distal femoral osteotomy (DFO), are options that attempt to decrease the loads on the articular cartilage of the meniscus-deficient compartment by replacing meniscal tissue or altering joint alignment. Clinical and biomechanical studies have reported promising outcomes for MAT, HTO, and DFO in the postmeniscectomized knee. These procedures can be performed alone or in conjunction with ligament reconstruction or chondral procedures (reparative, restorative, or reconstructive) to optimize stability and longevity of the knee. Complications can include fracture, nonunion, patella baja, compartment syndrome, infection, and deep venous thrombosis. MAT, HTO, and DFO are effective options for young patients suffering from pain and functional limitations secondary to meniscal deficiency.

Unicompartmental arthritis in the aging athlete: osteotomy and beyond

The vitality of the aging athlete is largely dependent on continued mobility and pain-free motion. The early onset of osteoarthritis often has devastating consequences for these athletes and if left untreated, mobility declines and eventually prevents sporting activities all together. Recent advances in operative treatment for unicompartmental arthritis of the knee aim to delay the need for total joint arthroplasty by preserving or restoring the form and function of the knee to allow for continued sport participation. This review focuses on the recent literature of several surgical treatment options for unicompartmental disease including cartilage procedures, osteotomy, and unicompartmental arthroplasty.

Patellar height modification after high tibial osteotomy by either medial opening-wedge or lateral closing-wedge osteotomies

PURPOSE

High valgus tibial osteotomy is used to treat medial femoro-tibial osteoarthritis. Changes in patellar height due to high valgus tibial osteotomy can cause technical difficulties during subsequent knee arthroplasty. The primary objective of this study was to assess the hypothesis that patellar height decreases after opening-wedge osteotomy and increases after closing-wedge osteotomy. The secondary objective was to assess whether frontal axis correction and tibial slope modification correlated with patellar height changes.

METHODS

A multicentre, prospective, comparative, observational, non-randomised study was conducted in consecutive patients undergoing isolated high valgus tibial osteotomy according to standard practice in each of the ten study centres. Patellar height was assessed based on the Caton-Deschamps index.

RESULTS

Of 321 included patients, 224 underwent opening-wedge and 97 closing-wedge osteotomy. Patellar height did not change significantly after closing-wedge osteotomy (1.07 ± 0.2 pre-operatively and 1.0 ± 0.19 postoperatively). Patellar height decreased significantly after opening-wedge osteotomy (from 0.98 ± 0.19 to 0.88 ± 0.21, p < 0.0001, mean decrease 9 ± 22%). Patellar height decreased by more than 20% in 49 (28%) patients after opening-wedge osteotomy. The patellar height decrease after opening-wedge osteotomy correlated significantly with axis correction magnitude and tibial slope change.

CONCLUSION

Our results support routine baseline measurement of patellar height before high valgus tibial osteotomy and posterior positioning of the opening wedge to limit the tibial slope change in patients requiring major axis correction by opening-wedge osteotomy.

LEVEL OF EVIDENCE

Prospective cohort study, Level II.