Femorotibial Angle Research Articles

The coronal alignment technique impacts deviation from native knee anatomy after total knee arthroplasty.

The aim of this study was to analyze and quantify the changes in native coronal alignment of a population of TKA patients according to different alignment goals. Five hundred and twenty TKAs were analyzed. The following angles were measured using an image-free navigation system prior to prosthetic implantation: medial femorotibial mechanical angle without stress and with maximum manual stress to reduce the deformity, medial distal femoral mechanical angle, medial proximal tibial mechanical angle. The native angles were derived from the osteoarthritic knee angles using a validated correction technique, and the overall, femoral and tibial coronal phenotypes were defined. Five different coronal alignment techniques were simulated: mechanical (MA), restricted mechanical (RMA), anatomical (AA), kinematic (KA) and restricted kinematic (RKA). The overall, femoral and tibial coronal phenotypes were compared before and after TKA. The primary endpoint was the binary criterion of whether or not TKA restored the natural overall phenotype. Secondary endpoints were the binary criteria of whether or not the natural femoral and tibial phenotypes were restored by TKA. The rates of restored and non restored phenotypes were compared with a Chi-square test at a 0.05 level of significance, with post hoc tests between all pairs of techniques at a 0.01 level of significance. The overall phenotype was restored significantly differently by the five alignment techniques: 15% for MA, 23% for RMA, 2% for AA, 100% for KA and 79% for RKA (p < 0.001). There was a significant difference between each of the technique pairs (p < 0.01 to p < 0.001), except for the mechanical alignment-restricted mechanical alignment pair. The femoral phenotype was restored significantly differently by the five alignment techniques: 37% for MA, 58% for RMA, 19% for AA, 100% for KA and 85% for RKA (p < 0.001). The tibial phenotype was restored significantly differently by the five alignment techniques: 36% for MA, 36% for RMA, 17% for AA, 100% for KA and 88% for RKA (p < 0.001). There was a significant difference between each pair of techniques for both femoral and tibial phenotypes (p < 0.01 to p < 0.001). Except for the kinematic alignment technique, the various alignment techniques induce significant changes in the pre-arthritic anatomy of the TKA patient. The surgeon must be aware of these modifications. The clinical relevance of this alteration still needs to be defined. III.

Asymmetries and relationships between muscle strength, proprioception, biomechanics, and postural stability in patients with unilateral knee osteoarthritis.

Background: The pathological mechanism of knee osteoarthritis (KOA) is unknown. KOA degeneration may be associated with changes in muscle strength, proprioception, biomechanics, and postural stability. Objective: This study aimed to assess asymmetries in muscle strength, proprioception, biomechanics, and postural stability of bilateral lower limbs in patients with unilateral KOA and healthy controls and analyze correlations between KOA and these parameters. Methods: A total of 50 patients with unilateral KOA (age range: 50-70) and 50 healthy subjects were recruited as study participants (age range: 50-70). Muscle strength, proprioception, femorotibial angle (FTA), femoral condylar–tibial plateau angle (FCTP), average trajectory error (ATE), and center of pressure (COP) sways areas were accessed in study participants, and the correlation between these variables was investigated. Results: In patients with unilateral KOA, lower limb muscle strength was significantly lower on the symptomatic side than on the asymptomatic side (p < 0.01), while the proprioception (degree error), FTA, FCTP, and ATE were substantially higher compared to the asymptomatic side (p < 0.01). However, no significant difference was observed in the healthy controls (p > 0.05). Patients with unilateral KOA had lower muscle strength than healthy controls (p < 0.05), but their proprioception (degree error: the difference between the target and reproduction angles), ATE, and COP sway areas were higher (p < 0.05). Muscle strength was found to be negatively correlated with ATE and COP sways areas (p < 0.05), whereas proprioception (degree error) was positively correlated with ATE and COP sways areas (p < 0.05) in all study participants. However, no correlation was found between FTA, FCTP, and ATE, COP sways areas in patients with unilateral KOA (p > 0.05). Conclusion: In patients with unilateral KOA, muscle strength, proprioception, biomechanics, and postural stability of bilateral limbs are asymmetrical in unilateral KOA patients. Muscle strength, proprioception, and postural stability are significantly associated variables, and changes in these variables should be considered in KOA prevention and rehabilitation.

A prospective comparative study on knee preservation surgeries in patients with osteoarthritis based on detailed evaluation of radiological parameters pre and post intervention

Knee osteoarthritis is a common joint disease, with an incidence of 30% of the population older than 60 years. The current belief is that the load is distributed along the mechanical axis, which is generally medial to the centre of the knee. Osteotomies to change the mechanical axis has been long described as a treatment of medial compartment OA, and proximal fibular osteotomy being the recent addition. The authors aimed to evaluate the change in radiological parameters of the knee alignment and asses its statistical significance. It is a hospital based prospective pre and post interventional study done at New Hospital Medical College Kota. The Sample size was calculated to be 34 subjects at α-error 0.05 and study power 80%. Radiological parameters were assessed in terms of Femorotibial angle, Mechanical axis deviation and Lateral joint space under standard magnification. Radiological parameters depicting the change in knee alignment were found to be statistically significant. Also, it correlates well with that described in other established studies.

Steep posterior slope of the medial tibial plateau and anterior cruciate ligament degeneration contribute to medial meniscus posterior root tears in young patients.

Medial meniscus posterior root tears (MMPRTs) occur most frequently in middle-aged and older adults. However, this serious condition can also occur in younger patients. The purpose of this study was to compare anterior cruciate ligament (ACL) degeneration and sagittal medial tibial slope in young adults with and without MMPRT. Eighteen healthy volunteers, 18 young patients (20-49years of age), and 30 middle-aged and older patients (50-70years of age) with MMPRT repair were included in the study. Sex, body mass index (BMI), femorotibial angle, ACL degeneration, and medial tibial slope angle were compared among the groups. ACL degeneration and medial tibial slope angle were assessed using magnetic resonance imaging. In the healthy volunteer group, the young patient group, and the older patient group, the medial tibial slopes were 3.5° ± 1.4°, 6.1° ± 2.7°, and 7.2° ± 1.9°, respectively, and the ACL degeneration rates were 5.6%, 38.9%, and 43.3%, respectively. Young patients with MMPRT had significantly steeper medial tibial slopes and ACL degeneration compared to those of the healthy volunteers (P < 0.05). The parameters of young patients were similar to those of older patients with MMPRT. In the multivariate logistic regression analysis, BMI, medial tibial slope, and ACL degeneration were significantly associated with MMPRT in young patients. BMI, steep medial tibial slope, and ACL degeneration contribute to MMPRT development in younger patients. Level III.

The relationship between the ‘‘Fujisawa point’’ and anatomical femorotibial angle following simulated open wedge high tibial osteotomy

BackgroundWe evaluated the relationship between the weight-bearing line (WBL) ratio and anatomical femorotibial angle (FTA) by simulated open wedge high tibial osteotomy (OWHTO). This study evaluated the correlation between the ‘‘Fujisawa point’’ and FTA, and identified factors which caused deviations between the two measurement methods. We hypothesized that the Fujisawa point corresponded with 170° of the FTA.MethodsPreoperative antero-posterior full-length lower limb radiographs of 82 patients were obtained for the OWHTO to place the WBL ratio at a target of 62.5% of the width of the tibial plateau (Fujisawa point). The coronal alignment was measured pre- and post-planning. The patients were divided into two groups by the post-planning FTA: a correspondence group (168.5°≦FTA≦171.5°) and a non-correspondence group (FTA < 168.5°, 171.5° < FTA). The relationship between the Fujisawa point and the FTA was analyzed with multivariate regression analysis.ResultsThe post-planning FTA was 169.8 ± 1.1° and within 170 ± 1.5° in 69 cases (84.1%) when the WBL ratio was 62.5%. The neck shaft angle was 128.1 ± 5.2° in the correspondence group, and 122.3 ± 6.3° in the non-correspondence group. The multivariate linear regression analysis revealed that the neck shaft angle was the only factor that predicted the correspondence of the Fujisawa point with the FTA at 170° (p = 0.006, odd 1.28).ConclusionsThe post-planning FTA converged at 170° when the WBL ratio passed through the Fujisawa point and the neck shaft angle was the only predictor.

Short-term effectiveness of high tibial osteotomy combined with arthroscopic surgery for knee varus arthritis and the results of secondary arthroscopic exploration

To investigate the effectiveness of high tibial osteotomy (HTO) combined with arthroscopic surgery to treat medial compartment knee osteoarthritis (KOA) and secondary arthroscopic exploration to evaluate the outcome of cartilage and meniscus. A clinical data of 57 patients with medial compartment KOA with varus deformity of lower extremities admitted between August 2014 and October 2018 were retrospectively analyzed. There were 23 males and 34 females with an average age of 51.2 years (range, 41-63 years). The disease duration ranged from 2 to 8 years, with an average of 4.7 years. The preoperative femorotibial angle was (179.86±4.69)°, the relative position of the lower limb mechanical axis passing through the tibial plateau was 24.21%±6.98%, and the posterior slope of the tibial plateau was (5.23±1.45)°. The Kellgren-Lawrence grade of knee joint was grade Ⅱ in 22 cases and grade Ⅲ in 35 cases. The preoperative Hospital for Special Surgery (HSS) score, Lysholm score, and visual analogue scale (VAS) score were 59.1±7.3, 48.8±7.6, and 6.2±1.1, respectively. Arthroscopic exploration was performed during the operation to record the articular cartilage degeneration in the weight-bearing area of the medial compartment (Outerbridge grade Ⅰ in 18 cases, grade Ⅱ in 30 cases, and grade Ⅲ in 9 cases) and the condition of the medial meniscus injury, and the corresponding treatment was performed. The coronal force line was adjusted according to the preoperative Kellgren-Lawrence grade of the knee joint during the operation. After operation, the relative position of the lower limb mechanical axis passing through the tibial plateau, the femorotibial angle, and the posterior slope of the tibial plateau were measured; the Kellgren-Lawrence grade of the knee joint was recorded; the Outerbridge grade of articular cartilage degeneration and the meniscus outcome were evaluated by combining with the MRI of the knee joint at 1 year after operation and the second arthroscopic exploration when the internal fixator was removed. The function and pain of the knee were evaluated by Lysholm score, HSS score, and VAS score. All the 57 patients were followed up 36-58 months with an average of 42.1 months. Incisions healed by first intention, and no neurovascular injury, intraarticular or hinge fractures occurred during operation, and no postoperative complications such as deep vein thrombosis of lower limbs and internal fixation failure occurred. All the osteotomy sites healed at 3 months after operation. At 1 year after operation, the internal fixator was removed, and the second arthroscopic exploration showed that there were 15 cases of Outerbridge grade Ⅰ, 31 cases of grade Ⅱ, and 11 cases of grade Ⅲ in the weight-bearing area of the medial compartment, and there was no significant difference when compared with preoperative grade ( Z=31.992, P=0.997); there was no cartilage degeneration in other compartments. Meniscus healing was seen in the injured meniscus, and no injury was seen in the normal meniscus. At last follow-up, there were 19 cases of Kellgren-Lawrence grade Ⅱ and 38 cases of grade Ⅲ, and there was no significant difference when compared with preoperative grade ( Z=49.049, P=0.764). The relative position of the lower limb mechanical axis passing through the tibial plateau was 59.16%±2.87%, and the femorotibial angle was (171.54±3.39)°, which significantly improved when compared with those before operation ( P<0.001). The posterior slope of the tibial plateau was (5.65±1.22)°, which was not significantly different from that before operation ( t=-1.673, P=0.096). The HSS score, Lysholm score, and VAS score were 82.3±7.7, 83.4±6.4, and 1.6±1.1 respectively, which were significantly different from those before operation ( P<0.001). HTO combined with arthroscopic surgery for medial compartment KOA with varus deformity of lower extremities can effectively improve the force line of lower extremities, relieve pain symptoms, and improve joint function, with satisfactory short-term effectiveness, and without significant progress in articular cartilage or meniscus injury after operation.

A PROSPECTIVE STUDY OF PROXIMAL FIBULAR OSTEOTOMY IN YOUNG PRIMARY MEDIAL OSTEOARTHRITIS KNEE AND ITS CLINICAL, FUNCTIONAL AND RADIOLOGICAL OUTCOME.

Background: Osteoarthritis (OA) commonly known as wear and tear arthritis. While it can occur even in young people, the chance of developing osteoarthritis rises after age 45. Proximal bular osteotomy (PFO) for young patients of OA knee joint is turning out to be an emerging concept with promising results. The aim of our study was to evaluate clinical, radiological and functional outcomes of PFO in young patients of primary medial compartment osteoarthritis of knee joint. Total 13 patients (20 knees) with moderate to severe pr Method: imary osteoarthritis of knee joint, who underwent PFO, were enrolled. Clinical data, Visual Analogue Scale score (VAS), Knee Society Score (KSS), Medial Knee Joint Space (MJS) and Femorotibial Angle measurements (FTA) were recorded. Patients were followed up at one, three, six months and yearly, postoperatively. 20 knee joints PFO. The mean VAS scores signicantly decreased from Results: 8.25 preoperatively to 2.21 at 12 months postoperatively. In most of patients, signicant medial pain relief was observed after PFO. Mean KSS at preoperative stage was 44.15, which was improved to 77 at 12 months postoperatively, which further suggests improvement in knee joint functions. There was noteworthy increase in Mean joint space postoperatively (1.17) as compared to preoperative stage (0.34). Mean FTA reduced from 182.64 degrees preoperatively to 178.61 at nal follow up. Our study shows Conclusion: that PFO remarkably causes pain relief and improves knee functions with increase in MJS and slight correction of varus deformity in young patients with primary osteoarthritis of knee joint.

Proximal fibular osteotomy relieves pain in spontaneous osteonecrosis of the knee: A retrospective study.

Spontaneous osteonecrosis of the knee (SONK) causes knee pain and joint motion limitation. Ischemia or insufficiency fracture may be the cause, but no consensus has been developed. Proximal fibular osteotomy (PFO) has been reported to relieve pain from osteoarthritis through medial compartment decompression. We reviewed the effect of this procedure on medial compartment SONK patients and explored clinical and radiological results.Since January 2018 to January 2020, the data of 12 knees (8 right and 4 left) from 11 SONK patients (9 women and 2 men) who received PFO were analyzed. The average age was 61.5 years. The diagnosis of SONK was established through weight-bearing anterior–posterior radiographs or magnetic resonance imaging (MRI). Visual analog scale (VAS) scores, Oxford knee score (OKS), Femorotibial angle (FTA), medial joint space, and lateral joint space were documented preoperatively and at follow up visits. Outcome assessment for the clinical and radiographic data was reviewed at 12- and 24-month follow-up visits.The mean follow up period was 33 months. All patients were able to walk with or without cane assistance the day after surgery. Both VAS score and OKS (preoperative: 6.6 ± 0.9 and 24.7 ± 3.8, respectively) improved significantly at the 12-month follow-up, and to 24-month follow-up (3.6 ± 1.3 and 35.6 ± 4.5, respectively, P < .05). Medial joint space ratio increased from 0.36 to 0.50 (P < .05). Changes of FTA were insignificant at any point of follow up. Four patients underwent follow-up MRI, and a decrease in the osteonecrotic area was clearly observed in 2 patients.By achieving medial knee decompression, PFO allowed quick weight-bearing recovery, pain relief, and improvement in knee function in SONK patients.

Is there any benefit in the combined ligament reconstruction with osteotomy compared to ligament reconstruction or osteotomy alone?: Comparative outcome analysis according to the degree of medial compartment osteoarthritis with anterior or posterior cruciate ligament insufficiency.

The purpose of this study was to compare the outcomes of middle-aged patients with anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) insufficiency by assessing different groups: high tibial osteotomy (HTO), HTO with combined ligament reconstruction, and isolated ligament reconstruction according to the alignment change and medial compartment osteoarthritis (OA). From 2014 to 2019, middle-aged (40-65years) patients with knee instability were enrolled in this retrospective study. They were categorized into three groups: group I, HTO; group II, HTO with combined ACL or PCL reconstruction; and group III, isolated ligament reconstruction. Radiological outcomes, including Kellgren-Lawrence grade, mechanical femorotibial angle (mFTA), weight-bearing line (WBL) ratio, and posterior tibial slope were compared. Knee stability and clinical outcomes were also compared. Seventy-nine patients completed the final assessment. Group I was older than other two groups (p = 0.006). Groups I and II had a higher body mass index (p = 0.043) and more preoperative varus alignment than group III (p < 0.001). OA severity was ranked in the order of group I, II, and III (p < 0.001). Group I showed more valgus alignment than group II after HTO (p = 0.024 for mFTA and 0.044 for WBL ratio, respectively). Compared to their preoperative status, all three groups showed significant improvement in knee stability (p < 0.001); however, group I showed inferior knee stability regardless of ACL or PCL reconstruction (p < 0.001 and 0.043, respectively). All clinical scores significantly improved in the three groups (p < 0.001), and they showed comparable clinical outcomes in the final assessment. Our strategy in managing middle-aged patients with knee instability according to the varus alignment and medial degeneration showed favorable stability and clinical outcomes. Middle-aged patients with knee instability should be managed with different strategies depending on their status. Case-control study; Level-III.

Using short knee radiographs to predict the coronal alignment after TKA: Is it an accurate proxy for HKA on full-length images?

BackgroundThe postoperative clinical outcomes has been extensively demonstrated to correlate with the coronal alignment after total knee arthroplasty (TKA). However, in different studies, either the hip-knee-ankle angle (HKA) on a full-length radiograph or the femorotibial angle (FTA) on a short knee film was used to categorize the postoperative coronal alignment. Meanwhile, several different FTA ranges were regarded as neutral alignment in different studies. As a result, it is still unknown that how FTA on short knee films and HKA related to each other. The FTA may be able to become an accurate proxy of HKA to predict the coronal alignment. The purpose of this study was to explore the correlation between the FTA and the HKA after TKA and to find the most accurate FTA range.MethodsAbout 223 patients were included in this study and standard weight-bearing short knee films as well as full-length radiographs were acquired. The pre- and postoperative FTA, as well as the postoperative anatomical lateral distal femoral angle (aLDFA) and anatomical medial proximal tibial angle (aMPTA) were measured on short knee films by two orthopedic surgeons independently. On full-length films, the pre- and postoperative FTA, the pre- and postoperative HKA, as well as the postoperative mechanical lateral distal femoral angle (mLDFA) and mechanical medial proximal tibial angle (mMPTA) were also recorded by two other surgeons independently. Pearson correlation analysis was performed to compare FTA and HKA, aMTPA and mMTPA, aLDFA and mLDFA, respectively.ResultsThe postoperative FTA and HKA had a good correlation (r = 0.86). The agreements were reached 82.7%, 71.0%, and 68.2% of all patients using three previously reported FTA ranges. When analyzing the independent alignment of the tibial tray and the femoral component, 84.1% and 57.9% of all patients was reached an agreement on the classification.ConclusionsOn most occasions, the consistence between the FTA and HKA in assessing the coronal limb alignment of the lower extremity and the tibial component is satisfactory. However, the postoperative full-length film is still needed to evaluate accurately the coronal alignment of the femoral component.

Minimum 5-Year Outcomes of Osteochondral Autograft Transplantation with a Concomitant High Tibial Osteotomy for Spontaneous Osteonecrosis of the Knee with a Large Lesion.

The purpose of this study was to evaluate the mid-term clinical outcomes of osteochondral autograft transplantation (OAT) with concomitant high tibial osteotomy (HTO) in spontaneous osteonecrosis of the knee (SONK) with a large lesion. A total of 48 knees of 48 consecutive patients with SONK (lesion size ≥4 cm2, no age criteria) who underwent opening wedge HTO and concomitant OAT were retrospectively investigated, and those who were followed up postoperatively for at least 5 years were included in this case series study. Clinical outcomes were evaluated using knee and function scores of Knee Society Score, radiographic outcomes were evaluated using the anatomical femorotibial angle (FTA), and these outcomes were compared between patients aged ≥70 years and <70 years. Of the 48 cases, a total of 43 cases were available for review at a minimum of 5 years, and 5 cases were excluded from the analysis. Overall, the mean knee score improved from preoperative 48.8 ± 13.3 to postoperative 87.9 ± 8.6 at 1 year (P < 0.05) and 85.0 ± 10.4 at final follow-up (P < 0.05 vs. preop., N.S. vs. 1 year). The mean function score also improved from preoperative 60.1 ± 10.9 to postoperative 87.3 ± 12.2 at 1 year (P < 0.05) and 84.2 ± 12.4 at final follow-up (P < 0.05 vs. preop., N.S. vs. 1 year). The mean standing FTA was corrected significantly from 181.1° ± 2.7° preoperatively to 169.7° ± 2.4° at 1 year (P < 0.05) and 169.4° ± 3.1° at final follow-up (P < 0.05 vs. preop., N.S. vs. 1 year). There were no significant differences in clinical and radiographic outcomes between patients aged ≥70 years and <70 years. There were 4 cases of lateral hinge fracture around the osteotomy site and 1 case of delayed union. None of the patients underwent revision surgery during the follow-up period (survival rate of 100%). Mid-term clinical outcomes of patients with SONK who underwent HTO and OAT with a relatively large lesion were good.

Evaluation of postoperative orientation of the knee and ankle joint after open wedge high tibial osteotomy

BackgroundCases with varus knee osteoarthritis (OA) often present concomitant ankle joint deformity and poor tibial plafond inclination (TPI) in the coronal plane. Although changes to the TPI with respect to the ground after open wedge high tibial osteotomy (OWHTO) have been described, reports on the relationship between the correction angle and severity of knee joint line obliquity (KJLO) are scarce. This study aimed to examine the correlation between the correction angle after OWHTO and the change in knee and ankle inclination with respect to the floor. MethodsBetween January 2016 and December 2019, 39 knees in 39 patients (mean age, 58.3 ± 9.7 years; male, 14 knees; female, 25 knees) underwent OWHTO for varus knee OA. The mean duration of follow up was 30.1 ± 9.8 months. Radiological severity of OA was evaluated for those with Kellgren-Lawrence grade 1–3. Preoperative and 1-year postoperative radiographs were used to examine the postoperative femorotibial angle, hip-knee angle, KJLO, TPI, talar tilt (TT), position of weight bearing line of the tibial plateau width (WBL ratio; %), and the relationship between the pre-to postoperative changes in each measured value and intraoperative correction angle. The relationship between the pre-to postoperative changes in each measured value and intraoperative correction angle were evaluated. Clinical evaluations were conducted before and 2 years after OWHTO using the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale of pain. ResultsThe mean pre-to post-operative changes were 3.2 ± 2.2 for KJLO and 3.1 ± 2.5 for TPI, both demonstrating significant differences as well as significant correlations with the correction angle. The knee joint demonstrated postoperative changes in the valgus direction and none in the varus direction with respect to the floor in all cases. Furthermore, the sum of changes to the KJLO and TPI showed a positive correlation that approximates the change in the correction angle. The mean pre- and postoperative 2-year KOOS subscale of pain were 50.2 ± 10.2 and 82.3 ± 9.1. There were no correlations between preoperative TPI, pre-to postoperative change in TPI, and 2-year postoperative of KOOS subscale of pain. ConclusionFor those who underwent OWHTO for varus OA, the knee joint changed from a preoperative varus malalignment to mild valgus malalignment, and the ankle joint tended to improve from a preoperative valgus malalignment to the postoperative neutral alignment with respect to the floor. Although a positive correlation was found in which the correction angle approximates the sum of changes to the KJLO and TPI, no significant difference was found between changes in KJLO and TPI nor in the ratio between the correction angle and changes in each measured value.

A New Total Knee Arthroplasty Technique for Valgus Knees that preserves the deep layer of the medial collateral ligament.

The aim of this study was to assess the outcomes and complications, such as tibiofemoral instability and recurrence of valgus deformity, of total knee arthroplasty for valgus knees with a new technique preserving the deep layer of the medial collateral ligament. In this study 33 (4 male and 29 female) patients, and a total of 36 (26 knees with osteoarthritis and 10 with rheumatoid arthritis) knees with a standing femorotibial angle (FTA) of <170° were included. Posterior Stabilized (PS) implants were used in 34 knees, rotating hinged knee implants were used in 2 knees. The procedures were carried out by a single surgeon protecting the deep layer of the medial collateral ligament. The patients' average age at the time of the operation was 67.6 ± 12 years, and the average follow-up period was 9.0 ± 3 years (range, 4-15 years). The Japanese Orthopaedic Association (JOA) knee score, range of motion (ROM) (extension/flexion; measured in degrees), FTA (measured in degrees) and complications were investigated. The Japanese Orthopaedic Association knee score significantly improved from an average of 51 ± 12 points before the operation to 86 ± 9 points after the operation (P <0.001). The extension ROM and flexion ROM improved from, -13 ± 13° to a postoperative average of -2 ± 4°, and 115 ± 25° to a postoperative average of 125 ± 18° respectively (P <0.001). The standing FTA significantly improved from 158 ± 9° to an average of 173 ± 2° after the operation (P <0.001). Thirty-four knees with severe valgus deformity were operated on using pos- terior stabilised implants, while only two knees required constrained implants. During follow-up, no complications, such as tibiofemoral instability, recurrence of valgus deformity, patellar necrosis, deep infection, wound problems, or peroneal nerve paralysis were observed. This study has shown us that after performing TKA while preserving the d-MCL for valgus knee deformity good clinical results were obtained and no complications were observed. Level IV, Therapeutic Study.

The Role of Prophylactic Peroneal Nerve Decompression in Patients with Severe Valgus Deformity at the Time of Primary Total Knee Arthroplasty.

BackgroundCommon peroneal nerve (PN) palsy after total knee arthroplasty (TKA) is a serious complication. Although many authors suggest delayed or immediate PN decompression after TKA in these patients, little is known about the role of prophylactic peroneal nerve decompression (PPND) at the time of TKA. The aim is to report the results of PPND in high-risk patients at the time of TKA.Materials and methodsA multi-institutional retrospective study review of nine patients (10 knees) who underwent PPND at the time of TKA was conducted. Patients who had severe valgus deformities (≥15° of femorotibial angle and not fully correctable by examination under anaesthesia) with or without flexion contractures were included. PPND was performed through a separate 3–4-cm incision at the time of TKA. The demographics, preoperative and postoperative anatomical and mechanical alignments, range of motion, operation time, postoperative neurological function and complications were recorded.ResultsAll patients had a completely normal motor and sensory neurological function postoperatively and no complications related to PPND were reported. All patients followed the standard physical therapy protocol after TKA without modifications.The mean preoperative femorotibial angle was 20° (range 15–33°) and the mean postoperative femorotibial angle was 6.3° (range 5–9°) (p = 0.005). The mean preoperative flexion contracture was 9 (range 0–20) and the mean residual contracture was 1.2° (range 2–5°) (p = 0.006).ConclusionPPND at the time of TKA is an option to minimise the risk of PN palsy in high-risk patients. This approach can be considered for patients undergoing TKA in selected high-risk patients with a severe valgus deformity.How to cite this articleMakhdom A, Hamilton AA, Rozbruch SR. The Role of Prophylactic Peroneal Nerve Decompression in Patients with Severe Valgus Deformity at the Time of Primary Total Knee Arthroplasty. Strategies Trauma Limb Reconstr 2022;17(1):38–43.

Medial meniscus extrusion and stage are related to the size of spontaneous osteonecrosis of the knee in patients who underwent high tibial osteotomy

PurposeSpontaneous osteonecrosis of the knee (SONK) causes acute atraumatic knee pain, and meniscus tears may be associated with the pathogenesis of SONK. The purpose of this study was to investigate the relationship of the type of meniscus tear and medial meniscus extrusion with SONK on the medial femoral condyle in patients who underwent surgical treatment with high tibial osteotomy due to severe knee pain. MethodsWe enrolled 98 patients with 102 knees who underwent medial opening wedge high tibial osteotomy (OWHTO) under the diagnosis of medial femoral condyle osteonecrosis at our hospital from December 2003 to January 2020. Based on the Koshino classification, cases of SONK were classified as stage 1–4. The relationships of demographic data, X-rays and MRI images, including femorotibial angle (FTA), meniscus tear type, and medial meniscus extrusion (MME), with the stage and volume of SONK were investigated. ResultsNinety-eight patients (29 males and 69 females), with an average age at surgery of 69.2 ± 9.6 years and Body mass index(BMI) of 61.0 ± 17.6 kg/m2. In 102 cases of SONK, 11 knees, 18 knees, 46 knees, and 27 knees were classified as stage 1–4, respectively. The mean SONK volume was 2161.61 µm (range 95.67–7484.68 µm) on preoperative MRI. The preoperative FTA (mean 180.86°, range 172–187°) was not associated with the stage or volume of SONK. Meniscus tears were found in all cases of SONK and consisted of 2 degenerations, 2 horizontal tears, 0 vertical tears, 40 radial tears, 4 complex tears, and 54 medial meniscus posterior root tears (MMPRTs). In addition, 99% (101/102) of knees showed more than 3 mm of meniscus extrusion. Although the meniscus tear type was not associated with SONK stage, there was a high rate of tears that caused disruption of the hoop strain, such as MMPRTs (52.9%) or radial tears (39.2%). MME was significantly related to SONK volume (r = 0.387, p < 0.001). ConclusionAll patients with SONK had coexisting meniscus tears, most menisci had medial extrusion, and a positive correlation was observed between MME and SONK volume.

Extra-articular factors of the femur and tibia affecting knee balance in mechanically aligned total knee arthroplasty

PurposeAlthough the joint gap distance and compartment loading of the knee are different parameters for obtaining balanced knees in patients with total knee arthroplasty (TKA), the extent to which a balanced knee is achieved in patients with mechanically aligned TKA (MA-TKA) is unclear. This study aimed to investigate the anatomical factors that affect the ligament balancing in MA-TKA according to a gap balancing technique by measured resection technique. MethodsThe relationship between compartment loading, gap distance, and lower limb alignment was analysed in forty-three patients who underwent navigation-assisted MA-TKA with the minimum soft-tissue release. Radiographic parameters included hip-knee-ankle (HKA) angle, femorotibial angle, mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle, posterior tibial slope, varus and valgus joint line convergence angle, femoral valgus angle, femoral shaft curve, and tibial shaft curve (TSC). ResultsThe postoperative HKA angle was 0.4±1.5°, with one coronal alignment outlier (2.3%). The gap distance showed four unbalanced knees for extension (9.3%) and flexion (9.3%), whereas the compartment loading identified 17 unbalanced knees (39.5%) at extension, 8 (18.6%) at 45° flexion, 7 (16.2%) at 90° flexion, and 10 (23.2%) at full flexion in MA-TKA. Mediolateral differentials of compartment loading correlated with femoral valgus angle (0°, 45°, and 90° flexion), mLDFA (45° and 90° flexion), and TSC (45° and 90° flexion). Femoral valgus angle and TSC were risk factors of the mediolateral differentials of compartment loading. ConclusionExtra-articular factors of femoral valgus angle, mLDFA, and TSC were associated with the mediolateral imbalance of compartmental loading, suggesting there is a limit to obtaining balanced knees in MA-TKA due to these unadjustable extra-articular factors. Level of evidenceIV, therapeutic case series.

Difference between medial and lateral tibia plateau in the coronal plane: importance of preoperative evaluation for medial unicompartmental knee arthroplasty

BackgroundSetting bone cutting levels for different joint line orientations of the medial and lateral tibia plateaus in individual patients is not clear. We aimed to evaluate the difference between joint line orientation of the medial and lateral tibia plateaus relative to the horizontal line of mechanical axis of tibia as tibial plateau difference (TPD) for an optimal tibial bone cut in medial unicompartmental knee arthroplasty (UKA) and determine which factors could influence TPD. We aimed to investigate the effect of preoperative TPD on polyethylene liner size in medial UKA.MethodsTPD in the coronal plane were measured in 181 female patients (181 knees). To determine the morphology of proximal tibia according to the severity of osteoarthritis, the patients were classified into three groups based on diagnosis and treatment: 80 who underwent robot-assisted medial UKA, 45 who underwent total knee arthroplasty (TKA), and 56 with early-stage osteoarthritis (OA) who had conservative management. Also, we divided the medial UKA group into two groups according to TPD (greater than or less than 5 mm) and compared polyethylene liner sizes.ResultsNo significant difference was observed in TPD (p = 0.662), difference between the medial and lateral femoral condyle levels (p = 0.54), medial proximal tibial angle (p = 0.169), or posterior tibial slope (p = 0.466) among the three groups. Increased TPD was significantly associated with increased mechanical femorotibial angle(mFTA) (p < 0.01). The medial UKA group was divided into two groups according to TPD greater or less than 5 mm. Thicker polyethylene liners were used for groups with TPD greater than 5 mm (8.5 ± 0.7 mm versus 8.2 ± 0.3 mm, p = 0.01). Additionally, the proportion of patients using the thinnest polyethylene (8 mm) in each TPD group (greater or less than 5 mm) was higher in patients with TPD less than 5 mm (82.4% versus 58.7%, p = 0.038).ConclusionsPreoperative measurement of TPD is important to help surgeons predict the most appropriate bone cutting level in the coronal plane in primary medial UKA. Tibial bone resection would be likely to be thicker than needed in patients with increased TPD in medial UKA.

A Long-Term Study of Alignment Correction Following Proximal Femoral Varus Osteotomy and Pemberton Osteotomy in Children With Legg-Calvé-Perthes Disease and Developmental Dysplasia of the Hip.

Proximal femoral varus osteotomy (PFVO) is a common procedure performed in children with developmental dysplasia of the hip (DDH) and Legg–Calvé–Perthes disease (LCPD). However, the long-term effect on angular deformities of the knees and ankles following PFVO remains controversial. This study investigated the relationship between PFVO and alignment changes in the knee and ankle after the procedure. Twenty-five patients undergoing PFVO procedure with a minimum 4-year evaluation period were enrolled in the study, including 14 unilateral LCPD and 11 unilateral DDH. The standing scanogram examinations were collected before the operation, immediately following surgery, after a 1-year follow-up, after a 3-year follow-up, and at the final visit to the clinic. The radiographic parameters included leg length, femoral neck-shaft angle (FNSA), femorotibial angle (FTA), mechanical axis deviation (MAD), tibiotalar angle (TTA), and mechanical lateral distal femoral angle (mLDFA). At the final examination, FNSA demonstrated insignificant change between the operative and non-operative limbs in the DDH group. Compared with the postoperative result, FNSA significantly improved in the LCPD group (p = 0.039). Both groups did not develop statistical significance in TTA, mLDFA, MAD, and leg length discrepancy after more than a 5-year follow-up. From a biomechanical perspective that the foot passes more medial to the knee under the center of leg mass, varus knee was prone to develop. In order to correct the mechanical axis, the knee reverted to a valgus position gradually. Our study indicates that patients with LCPD or DDH receiving PFVO and Pemberton osteotomy narrow the gap of angular growth in knees and ankles between the operative and non-operative limbs after a long-term follow-up.

ASSOCIATIONS BETWEEN BIOMECHANICAL MARKERS FROM A KNEE KINESIOGRAPHY EXAM AND PATIENT OUTCOME MEASURES: A COMPREHENSIVE REVIEW

Purpose: Patients with knee osteoarthritis (OA) may experience pain, functional limitations, and mechanical dysfunction during gait. Numerous studies have examined associations between patient-reported outcome measures (PROMS) and dynamic biomechanical markers, such as varus thrust during loading or dynamic flexion contracture. In contrast to static mechanical markers (e.g., the femoro-tibial angle), dynamic biomechanical markers are better associated with PROMS and objective performance tests. This has clinical relevance since studies have demonstrated the possibility to modify these markers.

Factors Associated with Postoperative Knee Joint Line Obliquity After Medial Open Wedge High Tibial Osteotomy

Background: There are still few reports on factors associated with postoperative knee joint line obliquity (KJLO). Purpose: The purpose was to determine preoperative radiographic factors that are associated with KJLO postoperatively after open wedge high tibial osteotomy (OWHTO) using multivariable linear regression analysis and multivariable logistic regression analysis. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 60 patients with 65 varus knees who underwent OWHTO between December 2012 and June 2018 at a single institution were retrospectively enrolled in this study. The authors evaluated radiologic parameters including the weightbearing line ratio, femorotibial angle, medial proximal tibial angle, mechanical lateral distal femoral angle (LDFA), lateral distal tibial angle, joint line convergence angle (JLCA), KJLO, and ankle joint obliquity. They also categorized these radiographic parameters as preoperative and postoperative and calculated the difference (Δ) between preoperative and postoperative values. To determine which of the radiographic parameters were most associated with postoperative KJLO, multivariable linear regression analysis was performed using the stepwise method. Multivariable logistic regression analysis was used to examine the relative contribution of the preoperative radiographic parameters to an abnormal postoperative KJLO (>4°). Results: In the multivariable linear regression analysis, the preoperative LDFA and JLCA showed a statistically significant correlation. Multivariable logistic regression analysis revealed that the mean preoperative LDFA was significantly larger in the group with abnormal KJLO than in the group with the control group (odds ratio, 1.84; 95% CI, 1.12-3.02; P = .02), while preoperative JLCA tended to be larger in the abnormal KJLO group than the control group but not statistically significantly different. Conclusion: KJLO after OWHTO was associated with preoperative LDFA and JLCA in multivariable linear regression analysis, and preoperative LDFA was the most important factor associated with abnormal KJLO after OWHTO in multivariable logistic regression analysis.