ACL degeneration after an excessive increase in the medial proximal tibial angle with medial open wedge high tibial osteotomy

Repair of medial meniscus posterior root tear is effective for root healing and cartilage regeneration in opening wedge high tibial osteotomy

PURPOSE

This study aimed to determine whether the repair of a medial meniscus posterior root tear (MMPRT) is effective for MMPRT healing, cartilage regeneration, and clinical outcomes in opening wedge high tibial osteotomy (OWHTO).

METHODS

This retrospective study included 80 patients who underwent OWHTO and subsequent second-look arthroscopy. The patients were divided into OWHTO-with-MMPRT-repair (n = 40) and OWHTO alone (n = 40) groups, and the healing rates (complete/partial/failure) were compared. Each group was further divided into over- and under-corrected subgroups to compare healing rates. The International Cartilage Repair Society (ICRS) grade, cartilage defect size, Koshino stage, ICRS cartilage repair assessment score of the medial femoral condyle (MFC), and International Knee Documentation Committee (IKDC) scores between the OWHTO-with-MMPRT-repair and OWHTO alone groups were compared according to whether microfracture was performed on the MFC.

RESULTS

The overall healing rate of the MMPRT was higher in the OWHTO-with-MMPRT-repair group than that in the OWHTO alone group (P < 0.001). In addition, in the subgroup analysis, no difference in the MMPRT healing rate between the over-correction and under-correction groups when MMPRT repair was performed (n.s). In contrast, without MMPRT repair, the healing rate was lower in the under-correction group than that in the over-correction group (P = 0.03). Cartilage regeneration of the OWHTO-with-MMPRT-repair group was superior to that of the OWHTO alone group (P < 0.05). The IKDC subjective scores of the OWHTO-with-MMPRT-repair and OWHTO alone groups were 34.5 and 33.1 before surgery (n.s) and 50 and 47.2 at one year after surgery, respectively (n.s). These differences between the two groups for cartilage regeneration and IKDC subjective scores showed the same pattern regardless of microfractures.

CONCLUSIONS

MMPRT repair during OWHTO might improve MMPRT healing, even with under-correction, and cartilage regeneration of MFC, regardless of microfracture. However, OWHTO with MMPRT repair might not improve short-term clinical outcomes compared to OWHTO alone. Further randomized clinical trials are necessary.

LEVEL OF EVIDENCE

III, Retrospective cohort study.

Clinical relevance of joint line obliquity after high tibial osteotomy for medial knee osteoarthritis remains controversial: a systematic review

PURPOSE

To systematically review the literature on the association between knee joint line obliquity (KJLO) and clinical outcome after high tibial osteotomy (HTO) for medial knee osteoarthritis and summarize the KJLO cut-off value used when studying this association.

METHODS

A systematic search was conducted in three databases (PubMed, Embase, and Web of Science) on September 2022, updated on February 2023. Eligible studies describing postoperative KJLO in relation to clinical outcome after HTO for medial knee osteoarthritis were included. Nonpatient studies and conference abstracts without full-text were excluded. Two independent reviewers assessed title, abstract and full-text based on the inclusion and exclusion criteria. The modified Downs and Black checklist was used to assess the methodological quality of each included study.

RESULTS

Of the seventeen studies included, three had good methodological quality, thirteen fair quality, and one had poor quality. Conflicting findings were shown on the associations between postoperative KJLO and patient-reported outcome, medial knee cartilage regeneration, and 10-year surgical survival in sixteen studies. Three good-quality studies found no significant differences in lateral knee cartilage degeneration between postoperative medial proximal tibial angle > 95° and < 95°. Joint line orientation angles by the tibial plateau of 4° and 6°, joint line orientation angle by the middle knee joint space of 5°, medial proximal tibial angles of 95° and 98°, and Mikulicz joint line angle of 94° were KJLO cut-off values used in the included studies.

CONCLUSION

Based on current evidence, the actual association between postoperative KJLO and clinical consequences after HTO for medial knee osteoarthritis cannot be ascertained. The clinical relevance of KJLO after HTO remains controversial.

LEVEL OF EVIDENCE

IV.

Relationship between histological changes of the anterior cruciate ligament and knee function in osteoarthritis patients

BACKGROUND

The function of the anterior cruciate ligament (ACL) in osteoarthritis (OA) of the knee remains to be elucidated. The purpose of this study is to evaluate histological changes of the ACL in end-stage knee OA and to clarify the relationship between histological changes in the ACL and knee function.

HYPOTHESIS

The hypothesis in this study was that ACL degeneration in knee OA is associated with decreased knee function.

PATIENTS AND METHODS

Eighty-two ACL specimens from 65 patients who underwent primary total knee arthroplasty (TKA) were investigated. The correlation between histological changes of the ACL (myxoid changes, chondroid metaplasia, total collagen degeneration, microcyst formation, vascular proliferation, and inflammatory cell infiltration) and knee function (range of motion, anterior tibial translation test, knee extension muscle strength, one-leg standing time, and functional reach test) were investigated. Age, body mass index, joint space narrowing, osteophyte formation, lower extremity alignment, and knee medial/lateral instability were also evaluated.

RESULTS

Myxoid change in the ACLs was significantly negatively correlated with one-leg standing time. Chondroid metaplasia was not correlated with knee function. Collagen degeneration in the ACL was significantly negatively correlated with knee flexion angle and one-leg standing time. In addition, a negative correlation between microcyst formation and knee flexion angle was noted. Osteophyte formation, particularly lateral femoral intercondylar osteophytes, was correlated with myxoid changes. The other parameters did not correlate with ACL histological changes.

DISCUSSION

Myxoid changes in the ACL were shown to correlate with knee function. The osteophyte score, particularly as related to lateral femoral intercondylar osteophytes, correlated with the severity of myxoid changes in the ACL in knee OA. Precise ACL evaluation should be included in the indications for ACL-retaining surgeries because ACL degeneration may be related to decreased knee function after surgery.

LEVEL OF EVIDENCE

IV, Diagnostic case series.

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

Background:

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

Purpose:

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

Study Design:

Case-control study; Level of evidence, 3.

Methods:

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

Results:

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

Conclusion:

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

Malrotation of whole-leg radiograph less than 10 degrees does not influence preoperative planning in open-wedge high tibial osteotomy

Coronal whole-leg radiography is generally used for preoperative open-wedge high tibial osteotomy (OWHTO) planning. Nevertheless, malrotational whole-leg radiographs could affect the planning, and the effects could possibly be strengthened by the knee flexed position. Consecutive 51 varus osteoarthritis knees that underwent OWHTO were included. The digitally reconstructed radiography (DRR) images parallel to the surgical epicondylar axis (neutral rotation; NR), 5° and 10° external rotation (ER) or internal rotation (IR), were reconstructed from preoperative CT. Preoperative weight-bearing line percentage (WBL%), medial proximal tibial angle (MPTA), planned opening angle, and planned postoperative MPTA were measured with OWHTO planning in each DRR image. Correlations among the measured differences relative to NR images and knee flexion angle were investigated. As the DRR image shifted from ER to IR, the differences in preoperative WBL% and MPTA gradually increased, whereas those in the opening angle gradually decreased, although all differences in the opening angle were within 0.5° on an average. Opening angle differences remarkably correlated with knee flexion angle, and knees with >10° flexion contracture had >1° difference in 10° ER or IR images. Planned postoperative MPTA had relatively high consistency regardless of whole-leg malrotation. The opening angle measurement using malrotated radiographs less than 10° would be clinically reliable in cases without knee flexion contracture. Nevertheless, extreme care should be taken in cases with >10° knee flexion contracture. The MPTA after medial opening would be a consistent and reliable parameter in whole-leg alignment evaluation.

Functional assessment of the anterior cruciate ligament in knee osteoarthritis

The purpose of this study was to evaluate anterior cruciate ligament (ACL) function in knee osteoarthritis (OA) and clarify the relationship of MRI and arthroscopic findings with ACL function. Eighty patients with knee OA were evaluated for anterior knee joint laxity, Kellgren-Lawrence grade, MRI ACL grade, arthroscopic ACL grade, osteophytes, and meniscus tears. ACL function was significantly correlated with osteophyte scores and medial and lateral meniscus tears. The MRI ACL grade was strongly correlated with the arthroscopic ACL grade, and anterior knee joint laxity decreased as the grades increased, suggesting a decrease in the elasticity of degenerated ACLs.

Large medial proximal tibial angles cause excessively medial tibiofemoral contact forces and abnormal knee kinematics following open-wedge high tibial osteotomy

BACKGROUND

Recurrent varus deformity and poor outcome sometimes occur following open-wedge high tibial osteotomy, but the mechanism remains unclear. The hypothesis of this study was that an excessively large medial proximal tibial angle with lateral joint surface inclination can worsen postoperative knee biomechanics.

METHODS

A computer-simulated knee model was validated based on a volunteer knee. Osteotomy models with medial proximal tibial angles ranging from 90° to 97° in 1° increments were developed. Varus alignment correction of the distal femur was performed in each model to maintain identical coronal alignment passing through a point 62.5% lateral to the tibial plateau. The peak tibiofemoral contact forces and knee kinematics were compared in each model during walking and squatting.

FINDINGS

All the osteotomy models demonstrated higher peak contact forces on the lateral tibiofemoral joints than on the medial tibiofemoral joints during walking. However, larger medial proximal tibial angles caused excessive increases in medial tibiofemoral contact forces, and the dominant tibiofemoral contact forces shifted to the medial side. Increased medial proximal tibial angles also caused progressive medial collateral ligament tension in knee flexion, but partial medial collateral ligament release effectively reduced medial tibiofemoral contact forces. Models with large medial proximal tibial angles showed nonphysiological roll-forward of the lateral femoral condyle during squatting and no screw-home movement around knee extension.

INTERPRETATION

Excessively large medial proximal tibial angles following open-wedge high tibial osteotomy resulted in increased medial tibiofemoral contact forces and abnormal knee kinematics during knee flexion due to medial joint line elevation and ligament imbalance.

Return to Work and Sport After Proximal Tibial Osteotomy and the Effects of Opening Versus Closing Wedge Techniques on Adverse Outcomes: A Systematic Review and Meta-analysis

BACKGROUND

Although many studies have reported successful functional outcomes after proximal tibial osteotomy (PTO), a paucity of literature has sought to quantify outcomes and current rates of return to sport (RTS) and return to work (RTW) after PTO.

PURPOSE

To (1) determine current rates of RTS and RTW after PTO and (2) quantify the incidence of complications and conversion to total knee arthroplasty (TKA) after PTO for all patients as well as those undergoing opening and closing wedge PTO.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

The Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed (2008-2019), EMBASE (2008-2019), and MEDLINE (2008-2019) databases were queried. Data pertaining to article information, patient demographics, surgical techniques, rates of complication and conversion to TKA, patient-reported outcome scores, RTS, and RTW were extracted. Data were synthesized, and a random effects meta-analysis of proportions using continuity correction methods was performed to determine the proportion of patients receiving opening and closing wedge PTO who experienced adverse events.

RESULTS

The review and meta-analysis included 33 studies involving 1914 patients who underwent PTO with a weighted mean ± SD age of 50.3 ± 9.9 years and body mass index of 26.9 ± 2.3 kg/m². The pooled RTS and RTW rates were 75.7% (range, 55%-100%) in 814 patients and 80.8% (range, 41%-100%) in 505 patients, respectively. The pooled TKA rate was 12.5% (range, 0%-35.7%) at a mean of 70.6 months and the pooled complication rate was 11.1% (range, 0%-28.6%). The overall random pooled summary estimate of the proportion of patients who underwent opening wedge PTO and subsequently converted to TKA was 2.0% (95% CI, 1.0%-4.0%; I² = 63.65) at a mean of 43.4 ± 31.9 months and who experienced a complication was 6.0% (95% CI, 3.0%-9.0%; I² = 87.10%). For closing wedge PTO, the proportion of patients who converted to TKA was 5.0% (95% CI, 1.0%-9.0%; I² = 93.1%) and experienced a complication was 2.0% (95% CI, 1.0%-3.0%; I² = 90.0%). Only 53.8% of studies that referenced RTS provided postoperative RTS rates, and 80% of studies that referenced RTW provided RTW rates. Only 1 study defined RTS criteria, no studies defined RTW criteria, and 31 different outcome measures were reported across all studies.

CONCLUSION

Patients undergoing PTO for osteoarthritis, cartilage defects, and symptomatic malalignment of the knee experience high rates of RTS and RTW. These patients also experience low rates of complications and conversion to TKA, regardless of opening or closing wedge technique. Significant heterogeneity exists with regard to criteria used to define RTS and RTW and patient-reported outcome measures used to assess clinical and functional improvements after PTO.

How does geometric change after open-wedge high tibial osteotomy affect anterior cruciate ligament status?

BACKGROUND

Open-wedge high tibial osteotomy (OWHTO) produces three- dimensional (3D) geometric changes. Among them, increased posterior tibial slope (PTS), and altered coronal inclination that induces unintended tibial translation may affect anterior cruciate ligament (ACL) status. The purpose of current study was to evaluate the geometric changes following OWHTO, such as increasing PTS and decreasing tibial subluxation, which may affect the status of ACL.

METHODS

From April 2014 to December 2015, a total of 72 knees in 64 patients that underwent OWHTO, second-look arthroscopy, and magnetic resonance imaging (MRI) assessment, were enrolled. Preoperative and postoperative coronal and sagittal translation, joint line orientation angle, the distance between medial femoral notch marginal line and medial tibial spine, and PTS were evaluated. ACL status was arthroscopically graded from grade 1 (best) to 4 (worst). The MRI signal of the graft in three portions (proximal, middle, and distal) was graded from grade 1 (best) to 4 (worst).

RESULTS

High grade (3: partial, and 4: complete rupture) was noted in 28 cases (38.9%) at the second-look arthroscopy compared with 10 cases (13.9%) at index arthroscopy. The MRI signal grade significantly increased at follow up MRI compared with preoperative MRI (P<0.01). An increased signal was commonly noted in the middle and distal portions of the graft.

CONCLUSIONS

Geometric changes after OWHTO were related to ACL deterioration. The ACL was commonly affected at the middle and distal portions and rarely at the proximal portion. There is a possibility of impingement because of the geometric changes.

LEVEL OF EVIDENCE

Level IV.