Increase in the Posterior Tibial Slope Provides Better Joint Awareness and Patient Satisfaction in Cruciate-Retaining Total Knee Arthroplasty.

The effect of the posterior tibial slope (PTS) in cruciate-retaining total knee arthroplasty (CR-TKA) on clinical outcomes remains unclear. We aimed to investigate (1) the effect of alteration of the PTS on clinical outcomes, including patient satisfaction and joint awareness, and (2) the relationship between the patient-reported outcomes, the PTS, and compartment loading. Based on the alteration of the PTS after CR-TKA, 39 and 16 patients were stratified into increased and decreased PTS groups, respectively. Clinical evaluation was performed by the Knee Society Score (KSS) 2011 and the Forgotten Joint Score-12 (FJS-12). Compartment loading was intraoperatively assessed. KSS 2011 (symptoms, satisfaction, and total score) was significantly higher (p = 0.018, 0.023, and 0.040, respectively), and FJS ("climbing stairs?") was significantly lower (p = 0.025) in the increased PTS group compared with the decreased PTS group. The decrease in both medial and lateral compartment loading of Δ45°, Δ90°, and ΔFull was significantly greater in the increased PTS group than in the decreased PTS group (p< 0.01 for both comparisons). Medial compartment loading of Δ45°, Δ90°, and ΔFull significantly correlated with KSS 2011 for "symptom" (r = - 0.4042, -0.4164, and -0.4010, respectively; p = 0.0267, 0.0246, and 0.0311, respectively). ΔPTS significantly correlated with medial compartment loading differentials of Δ45°, Δ90°, and ΔFull (r = - 0.3288, -0.3792, and -0.4424, respectively; p = 0.0358, 0.01558, and 0.0043, respectively). Patients with increased PTS showed better symptoms and higher patient satisfaction compared with those with decreased PTS following CR-TKA, possibly due to a greater decrease in compartment loading during knee flexion.Level of evidence:level IV, therapeutic case series.

Effect of medial opening wedge distal tibial tuberosity osteotomy on possible neuropathic pain in patients with osteoarthritis of the knee.

BACKGROUND: There is a paucity of literature regarding the changes and features of neuropathic pain (NP) in knee osteoarthritis (OA) following medial opening wedge distal tibial tuberosity osteotomy (OWDTO). This study aimed to investigate the effect of OWDTO on NP in knee OA; we hypothesized that OWDTO improves knee symptoms and functions and also meets patient satisfaction in those with knee OA with possible NP or without NP. METHODS: Fifty-two consecutive patients who underwent OWDTO were categorized into the unlikely NP and possible NP groups using the painDETECT questionnaire. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) score and the Knee Society Score 2011 (KSS 2011) were compared between the groups preoperatively and at the 1-year follow-up. RESULTS: The number of patients having possible NP significantly decreased from 12 (23.1%) preoperatively to one (1.9%) postoperatively (p < 0.001). The patient with postoperative possible NP also had possible NP preoperatively. All preoperative sub-scores of WOMAC were significantly higher in the possible NP group than in the unlikely NP group (p = 0.018, 0.013, 0.004, and 0.005, respectively); however, the postoperative scores did not differ between the two groups. Regarding the KSS 2011, the preoperative scores for symptom and functional activities were significantly lower in the possible NP group than in the unlikely NP group (p = 0.031 and 0.024, respectively). CONCLUSIONS: OWDTO is an effective surgery for patients with possible NP; it improves symptoms and knee function as well as meets patient satisfaction. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Can radiological findings detect neuropathic pain in patients with osteoarthritis of the knee undergoing surgery?

OBJECTIVES: The mechanism underlying neuropathic pain (NP) in osteoarthritis (OA) of the knee is not completely understood. This study aimed to investigate whether possible NP in patients with knee OA undergoing knee surgery is associated with specific radiological findings. METHODS: This study included 197 patients who underwent knee surgery for symptomatic knee OA. Clinical evaluation was performed using the Central Sensitization Inventory (CSI), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and PainDETECT questionnaire. Radiological evaluation was performed using the hip-knee-ankle (HKA) angle, posterior tibial slope (PTS), varus and valgus laxities, and magnetic resonance imaging OA Knee Score (MOAKS). Radiological findings were compared between patients with possible and unlikely NP. Logistic regression analysis was performed to identify the predictive factors for NP. RESULTS: There were 163 and 34 patients with unlikely NP and with possible NP, respectively. The percentage of patients with CSI score ≥ 40 was significantly higher in the possible NP group than in the unlikely NP group (17.6% vs. 6.1%). Patients with possible NP had worse WOMAC scores than patients with unlikely NP. There were no significant positive associations between the possible NP and radiological findings in knee OA. Regression analysis showed no predictive factors for possible NP. CONCLUSIONS: Possible NP is not associated with specific radiological findings in knee OA. Patients with possible NP may mediate CS and experience more severe symptoms, including decreased knee function and lower quality of life, than patients with unlikely NP.

Joint gap produced by manual stress is dependent on the surgeon's experience and is smaller in flexion in robotic-assisted total knee arthroplasty.

PURPOSE: This study aimed to retrospectively investigate (1) the reproducibility of gap measurements by manual stress using the Z-shaped retractor depending on the surgeon's experience with this maneuver and (2) the consistency of the gap distraction force produced by manual stress throughout the range of motion (ROM) in the robotic-assisted total knee arthroplasty (TKA). It was hypothesized that the joint gap produced by manual stress is not reproducible depending on the surgeon's experience, and the distraction force applied by manual stress throughout the ROM is not constant. METHODS: Medial and lateral joint gaps were obtained throughout the ROM by manual stress or a tensioner by two surgeons with different levels of experience in robotic-assisted TKA. The association between the differences in gap measurement by the two surgeons and the preoperative radiographic parameters, including the hip-knee-ankle (HKA) angle and absolute and relative varus/valgus laxities were analyzed. RESULTS: The experienced surgeon produced significantly greater gaps than the inexperienced surgeon from 0° to 100° flexion, with a mean difference of 0.35 ± 0.12 mm in the medial gap (p < 0.0001), and from 10° to 120° flexion with a mean difference of 0.57 ± 0.13 mm in the lateral gap (p < 0.0001). The tensioner produced a significantly greater medial gap from 70° to 110° flexion with a mean difference of 0.32 ± 0.01 mm in the medial gap (p < 0.0001) and from 0° to 110° flexion with a mean difference of 1.12 ± 0.26 mm in the lateral gap (p < 0.0001). The differences in gap distance by manual stress between experienced and inexperienced surgeons were moderately correlated with the HKA angle in the lateral gap (r = 0.40, p = 0.01). The gap differences due to manual stress and a tensioner showed moderate negative correlation with the HKA angle in the medial gap (r = - 0.50, p = 0.001) and weak negative correlation with the absolute valgus laxity in the lateral gap (r = - 0.35, p = 0.03). CONCLUSIONS: The joint distraction force by manual stress may differ depending on the surgeon's experience and tended to be smaller in deep flexion; therefore, the flexion gap may be underestimated. Surgeons should determine implant positioning considering gap balance by manual stress, taking into account these characteristics of the manual stress maneuver. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Thinner tuberosity osteotomy is more resistant to axial load in medial open-wedge distal tuberosity proximal tibial osteotomy: A biomechanical study.

BACKGROUND: The purpose of this study was to investigate axial load resistance of the tibia depending on the thickness of tibial tuberosity osteotomy in medial open-wedge distal tuberosity proximal tibial osteotomy (OWDTO). The hypothesis is that a thin tibial tuberosity osteotomy shows high axial load resistance of the tibia. METHODS: The OWDTO model was constructed from imitation bones of the tibia. Distal tibial tuberosity osteotomy was performed with thicknesses of 7, 14, and 21 mm (n = 5 for each group). Cyclic axial-load fatigue tests were performed to investigate the strain at five measurement points on the OWDTO model. An axial-load failure test was also performed to investigate the maximum strain for failure. RESULTS: The 7-mm OWDTO model showed a significantly lower stain range than the 14-mm model at the middle part of the lateral hinge (P = 0.0263, mean difference: -852.6 µÎµ), posterior part (P = 0.0465, mean difference: -1040.0 µÎµ), posterior tibial cortex (P < 0.0001, mean difference: -583.4 µÎµ), and plate (P = 0.0029, mean difference: -121.6 µÎµ). There were no significant differences in the strain at the tibial tuberosity between the groups. The axial load for complete failure was significantly higher in the 7-mm model than in the 21-mm model (P = 0.0010, mean difference: 2577.0 N). The failure points were at the lateral hinges. CONCLUSIONS: Thinner distal tibial tuberosity osteotomy is more resistant to axial load and may be recommended for the prevention of tibial and lateral hinge fractures after OWDTO.

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.

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

PURPOSE: Although 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. METHODS: The 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). RESULTS: The 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. CONCLUSION: Extra-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 EVIDENCE: IV, therapeutic case series.

Medial proximal tibial angle at the posterior tibial plateau represents the pre-arthritic constitutional medial proximal tibial angle in anterior cruciate ligament-intact, advanced osteoarthritis of the knee.

PURPOSE: In kinematically aligned total knee arthroplasty (TKA), it is necessary to infer the pre-arthritic constitutional medial proximal tibial angle (MPTA) in advanced osteoarthritis (OA) of the knee with bone loss. The aim of this study was to investigate whether MPTA at the posterior tibial plateau represents the pre-arthritic constitutional MPTA in anterior cruciate ligament (ACL)-intact, advanced OA knees. It was hypothesized that MPTA at the posterior tibial plateau represents the pre-arthritic constitutional MPTA of ACL-intact, advanced knee OA. METHODS: One hundred varus, anterior cruciate ligament (ACL)-intact, advanced OA knees were analysed. The hip-knee-ankle (HKA) angle and MPTA were assessed on computed radiography (CR) and MPTAs at the anterior, middle, and posterior part of the tibial plateau were assessed on computed tomography (CT) images. The association between these parameters was also analysed. RESULTS: CR images showed an HKA angle of 172.4 ± 4.1° and MPTA of 84.3 ± 2.5°. CT images showed different MPTAs in the three regions, ranging from 83.9 ± 2.4° to 85.9 ± 2.8°. The middle MPTA was the lowest at 83.9 ± 2.4°. HKA angle correlated with the middle MPTA (r = 0.3355, 95% confidence interval [CI] 0.1489-0.4991, p = 0.0006) and ΔMPTA (Middle-Posterior) (r = 0.5128, 95% CI 0.3518-0.6443, p < 0.0001). CONCLUSION: The MPTA at the posterior tibial plateau represents the pre-arthritic constitutional MPTA in ACL-intact, advanced OA knees. LEVEL OF EVIDENCE: III, retrospective cohort study.

Compensatory Pelvic Retro-Rotation Associated with a Decreased Quality of Life in Patients with Normal Sagittal Balance.

STUDY DESIGN: Cross-sectional observational study. PURPOSE: To examine whether pelvic rotation as a compensatory mechanism for sagittal imbalance is related to quality of life (QOL). OVERVIEW OF LITERATURE: Poor sagittal alignment is associated with compensatory pelvic retroversion and decreased QOL. Whether the compensatory pelvic tilt (PT) influences QOL is unclear. METHODS: Overall, 134 subjects aged ≥20 years with lower back pain were included (104 females; mean age, 70±9.8 years). Sagittal vertical alignment (SVA) and PT were analyzed radiographically. Patients were stratified into three groups based on SVA values: good alignment (group G), intermediate alignment (group I), and poor sagittal alignment (group P). Patients in group I were further categorized into two groups: low PT and high PT. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) was used for clinical assessment, and the scores were compared between groups. RESULTS: As SVA increased, PT and lumbar lordosis (LL) increased and decreased, respectively. PT and LL differed significantly between groups G and P (p<0.01 for each comparison). Within group I, there was no significant difference in SVA between the high PT and low PT groups, suggesting that the high PT group had acquired a compensated sagittal balance. Importantly, all domains in the JOABPEQ (except for lower back pain) were significantly lower in the high PT group than in the low PT group (p<0.05 for every comparison). CONCLUSIONS: This study showed that focusing solely on SVA as a single indicator can cause important losses in QOL to be overlooked in patients with lumbar disorders. Although pelvic retroversion can compensate for sagittal balance, it is associated with a significant decrease in QOL. To improve the assessment of patients with lumbar disorders, PT should be considered besides SVA.

Clinical course and outcomes of simultaneous-versus staged-bilateral medial opening wedge high tibial osteotomy.

BACKGROUND: Difference in the clinical course and outcomes between simultaneous- and staged-bilateral medial opening wedge high tibial osteotomies (OWHTOs) over time was unknown. The study hypothesis was that patients who underwent simultaneous-bilateral OWHTO (SMBO) have a more rapid improvement in knee function than those who underwent staged-bilateral OWHTO (STBO) due to difference in the change of lower limb alignment between SMBO and STBO. METHODS: The records of 56 knees in 28 patients who underwent either SMBO (n = 28) or STBO (n = 28) were retrospectively analysed. The time course data of weight-bearing line percentage (%WBL), joint line convergence angle (JLCA), and Knee Society Score were compared between the two procedures. RESULTS: Hospitalisation for SMBO was longer than that for STBO by 1 week. No significant difference was observed in %WBL between the two procedures. The JLCA was significantly lower with SMBO than with the first-stage surgery of STBO (P < 0.05), but it became equivalent in both groups at the last follow-up. The knee scores in both SMBO and the first-stage surgery of STBO significantly improved in approximately 1 year. The function scores in the first-stage surgery of STBO did not significantly improve until the completion of the second-stage surgery whereas those in SMBO significantly improved 1 year after surgery and become stable. The function score 1 year after surgery was significantly higher in SMBO than in the first-stage surgery of STBO (p < 0.001). CONCLUSIONS: Although both SMBO and STBO achieved the desired therapeutic results, SMBO led to earlier functional improvement and decreased JLCA compared with STBO.

Acetabular perforation after medial migration of the helical blade through the femoral head after treatment of an unstable trochanteric fracture with proximal femoral nail antirotation (PFNA): a case report.

The proximal femoral nail antirotation is a new generation of intramedullary device for the treatment of trochanteric femoral fractures, having a helical blade rather than a screw for suggested better purchase in osteoporotic bone. However, it is not free of complications. Few reports are available on postoperative perforation of the helical blade through the femoral head as a unique complication of proximal femoral nail antirotation. We report a 79-year-old woman with acetabular perforation after migration of the helical blade through the femoral head after an unstable trochanteric fracture, which was fixed with a proximal femoral nail antirotation.

Symptomatic lumbar mobile segment with spinal canal stenosis in a fused spine associated with diffused idiopathic skeletal hyperostosis.

BACKGROUND CONTEXT: Chronic, continuous stress at the junction of a stable/unstable site of the spine in diffuse idiopathic skeletal hyperostosis (DISH) has been reported to cause a nonunion. Back pain resulting from the nonunion has been rarely reported and few operative treatments have been suggested. PURPOSE: To report and discuss the pathogenesis, treatment, and surgical outcome of a rare cause of back pain. STUDY DESIGN: Case report of back pain caused by a single lumbar segment is lacking bony union at the caudal end of a fused spine associated with diffuse idiopathic skeletal hyperostosis. METHODS: Back pain in a 66-year-old man who had suffered for 10 years worsened. The back pain and thigh pain became intolerable, and the left buttock and thigh became numb. Radiographs and computed tomography images showed continuous hyperostosis in the anterior aspect of the vertebral bodies from C2 to L2. At the caudal adjacent level of these fused segments, L2/3 level was mobile and had canal stenosis. Decompression and posterior lumbar interbody fusion (PLIF) were performed. RESULTS: The pain disappeared soon after the operation. The nonunited segment showed bony union at the 5-year follow-up. CONCLUSIONS: PLIF may be an option for surgically treating symptomatic nonunited lumbar segments at the caudal end of a fused spine with DISH in cases unresponsive to conservative treatment.

Spondylolysis of the second lumbar vertebra treated with segmental wiring and bone grafting.

Spondylolysis affects mostly the lower lumbar spine and rarely the upper lumbar spine. In a literature research, we found that the descriptions of spondylolysis of the upper lumbar spine had been reported mainly with the outcomes of conservative treatment using lumbosacral supports. However, an indication of surgical treatment has rarely been reported. Ravichandran et al reported 2 cases of spinal fusion, decompression or a combination of these procedures, but the procedures have not proved satisfactory in cases of upper lumbar spondylolysis. We found no reports of segmental wire fixation and bone grafting for upper lumbar spondylolysis. Herein, we report spondylolysis of the second lumbar vertebra in a 27-year-old man. He presented with pain and tenderness at the L2 spinous process, and swollen paravertebral muscles. The patient first became aware of lumbago at age 24 years. Much of his work involved heavy labor. He was diagnosed with spondylolysis of L2 and treated conservatively by a general orthopedist from age 25 to 27 years, but without improvement. We performed segmental wire fixation of the transverse and spinous processes of L2, followed by a bone graft. Six months after surgery, the lumbago had resolved and the patient was able to return to work. Three years after surgery, his pain is completely resolved. This is the first report in the English literature in which a successful indication for symptomatic spondylolysis in the upper lumbar spine is described.

Effects of wearing halo vest on gait: three-dimensional analysis in healthy subjects.

STUDY DESIGN: The effects of a halo vest on the gait were studied. The motions of the head, shoulder girdle, trunk, and hip were analyzed with the vest and tong either connected by bars or unconnected. OBJECTIVE: To analyze effects of wearing a halo vest using three-dimensional motion analysis. SUMMARY OF BACKGROUND DATA: We have little information on the effects of halo vests on gait. METHODS: Twenty-eight healthy male volunteers participated (age, 32 +/- 7.2; average +/- SD). The halo tong and vest were applied in a noninvasive way. Gait patterns and three-dimensional motions of the head, shoulder girdle, trunk, pelvis, and hip in control and halo vest gaits were analyzed using rectangular force plates and a VICON system (Vicon Motion System Ltd., Oxford, UK). RESULTS: The halo vest decreased the gait speed; it increased the duration of strides and decreased the length of strides. It also decreased the motions between the shoulder girdle and the trunk, the trunk and the pelvis, and decreased the motion of the hip in 3 planes. CONCLUSION: Our study provides preliminary evidence that halo vests increase stride time and decrease stride length and reduce motions between the shoulder girdle and the trunk, the trunk and the pelvis, and decreases the motion of the hip.