Monoplanar versus biplanar medial open-wedge proximal tibial osteotomy for varus gonarthrosis: a comparison of clinical and radiological outcomes

Purpose

We compared clinical and radiological results of two proximal tibial osteotomy (PTO) techniques: monoplanar medial open-wedge osteotomy and biplanar retrotubercle medial open-wedge osteotomy, stabilised by a wedged plate.

Methods

We evaluated 88 knees in 78 patients. Monoplanar medial open-wedge PTO was performed on 56 knees in 50 patients with a mean age of 55 ± 9 years. Biplanar retrotubercle medial open-wedge PTO was performed on 32 knees in 28 patients with a mean age of 57 ± 7 years. Mean follow-up periods were 40.6 ± 7 months for the monoplanar PTO group and 38 ± 5 months for the biplanar retrotubercle PTO group. Clinical outcome was evaluated using the hospital for special surgery scoring system, and radiological outcome was evaluated by the measurements of femorotibial angle (FTA), patellar height and tibial slope changes.

Results

In both groups, post-operative HSS scores increased significantly. No significant difference was found between groups in FTA alteration, but the FTA decreased significantly in both groups. Patellar index ratios decreased significantly in the monoplanar PTO group (Insall-Salvati Index by 0.07, Blackburne-Peel Index by 0.07), but not in the biplanar retrotubercle PTO group. Tibial slopes were increased significantly in the monoplanar PTO group, but not in the retrotubercle PTO group.

Conclusions

Biplanar retrotubercle medial open-wedge osteotomy and monoplanar medial open-wedge osteotomy are both clinically effective for the treatment for varus gonarthrosis. Retrotubercle osteotomy also prevents patella infera and tibial slope changes radiologically.

Level of evidence

Therapeutic study, prospective comparative study, Level II.     

A case series of lateral opening wedge high tibial osteotomy for valgus malalignment

Introduction

Lateral opening wedge high tibial osteotomy is a rarely employed surgical technique used for the treatment of lateral knee pain and degeneration in the setting of genu valgum. There exists little evidence of the suitability of this procedure for patients requiring osteotomies with a small correction.

Materials and methods

A case series of 23 patients (24 knees) undergoing lateral opening wedge high tibial osteotomy with a minimum follow-up of 2 years was performed between 2002 and 2008. A surgical technique avoiding the need for fibular osteotomy is described. Adverse events, patient-reported outcomes and radiographic measures of alignment were assessed at baseline, at 6 months postoperatively, and at time of final follow-up. A subgroup of 12 patients also underwent 3D gait analysis at the same time points.

Results

The mean follow-up was 52 months (±20.4). Statistically and clinically significant improvements were identified in the lower extremity functional scale [mean change (95 %CI) = 10 (2.4, 17.6)], and in the knee injury and osteoarthritis outcome score [mean change (95 %CI) = 10.9 (0.5, 21.4)]. Mechanical axis changed from 2.4 ± 2.4° valgus to 0 ± 2.6° varus (p<0.001), anatomical axis from 6.9 ± 2.8° to 4.7 ± 2.5° valgus (p < 0.001), with weight-bearing line offset changing from 60.2 ± 11.4 % to 49.5 ± 12.4 % (p < 0.001). Change in lateral tibial slope, from 6.5 ± 2.2° to 7.5 ± 2.3°, was very small and not statistically significant (n.s.). The peak knee adduction moment during gait significantly increased [mean change (95 %CI) = 0.72 %BW*Ht (0.42, 1.02), suggesting a medial shift in dynamic knee joint load. Two patients underwent total knee arthroplasty during the study period.

Conclusions

Lateral opening wedge high tibial osteotomy is a viable surgical option for patients with lateral knee pain and valgus malalignment requiring small degrees of correction.

Level of evidence

IV.     

Posteromedially placed plates with anterior staple reinforcement are not successful in decreasing tibial slope in opening-wedge proximal tibial osteotomy

Purpose

To document the effectiveness of a novel technique to decrease tibial slope in patients who underwent a proximal opening-wedge osteotomy with an anteriorly sloped plate placed in a posteromedial position. The hypothesis was that posteromedial placement of an anteriorly sloped osteotomy plate with an adjunctive anterior bone staple on the tibia would decrease, and maintain, the tibial slope correction at a minimum of 6 months following the osteotomy.

Methods

All patients who underwent biplanar medial opening-wedge proximal tibial osteotomy with anterior staple augmentation to decrease sagittal plane tibial slope were included, and data were collected prospectively and reviewed retrospectively. Indications for decreasing tibial slope included medial compartment osteoarthritis with at least one of the following: ACL deficiency, posterior meniscus deficiency, or flexion contracture. Preoperative, immediate postoperative, and 6-month postoperative radiographs were reviewed.

Results

Twenty-one patients (14 males and 7 females) were included in the study with a mean age of 36.5 years. Intrarater and interrater reliability of slope measurements were excellent at all time points (ICC ≥ 0.94, ICC ≥ 0.85). The osteotomy resulted in an average tibial slope decrease of 0.8 from preoperative (n.s.). At 6-month postoperative, average slope was not significantly different from time-zero postoperative slope (mean = +0.2°).

Conclusions

The most important finding of this study was that posteromedial placement of an anteriorly angled osteotomy plate augmented with an anterior staple during a biplanar medial opening-wedge proximal tibial osteotomy did not decrease sagittal plane tibial slope. Whether a staple was effective in maintaining tibial slope from time zero to 6 months postoperatively was unable to be assessed due to no significant change in tibial slope from the preoperative postoperative states. The results of this study note that current osteotomy plate designs and surgical techniques are not effective in decreasing sagittal plane tibial slope.

Level of evidence

IV.

     

Bone marrow-derived cell mobilization by G-CSF to enhance osseointegration of bone substitute in high tibial osteotomy

Purpose

To evaluate granulocyte colony-stimulating factor (G-CSF) efficacy in accelerating bone regeneration following opening-wedge high tibial valgus osteotomy for genu varum.

Methods

A phase II trial was conducted for evaluating the preoperative administration of G-CSF given at 10 μg/kg/day for 3 consecutive days with an additional half-dose 4 h before the opening-wedge high tibial valgus osteotomy. Overall, 12 patients (Group A) received G-CSF treatment, and the subsequent 12 patients (Group B) underwent surgery without G-CSF. The osteotomy gap was filled by a bone graft substitute. Bone marrow cell (BMC) mobilization was monitored by CD34+ve cell and clonogenic progenitor cell analysis. All patients underwent a clinical (Lysholm Knee Scale and SF-36) and radiographic evaluation preoperatively, as well as at given intervals postsurgery.

Results

All patients completed the treatment program without major side effects; G-CSF was well tolerated. BMC mobilization occurred in all Group A patients, with median peak values of circulating CD34+ve cells of 110/μL (range 29–256). Circulating clonogenic progenitors paralleled CD34+ve cell levels. A significant improvement in Lysholm Knee Scale was recorded at follow-up in Group A compared to Group B. At the radiographic evaluation, there was a significant increase in osseointegration at the bone-graft junction in Group A at 1, 2, 3 and 6 months postsurgery compared to Group B. The computerized tomography scan of the grafted area at 2 months postsurgery showed no significant difference in the quality of the newly formed bone between the two Groups.

Conclusions

Although the limited number of patients does not allow firm conclusions, the study suggests that G-CSF can be safely administered preoperatively in subjects undergoing opening-wedge high tibial valgus osteotomy; in addition, the clinical, radiographic and CT monitoring indicate that G-CSF and/or mobilized BMCs may hasten bone graft substitute osseointegration.

Level of evidence

I.     

Combined ACL reconstruction and closing-wedge HTO for varus angulated ACL-deficient knees

Purpose

To report the medium-term clinical and radiographic outcomes of a group of patients who underwent anterior cruciate ligament (ACL) surgery combined with high tibial osteotomy (HTO) for varus-related early medial osteoarthritis (OA) and ACL deficiency knee.

Methods

Thirty-two patients underwent single-bundle over-the-top ACL reconstruction or revision surgery and a concomitant closing-wedge lateral HTO. The mean age at surgery was 40.1 ± 8.1 years. Evaluation at a mean of 6.5 ± 2.7 years of follow-up consisted of subjective and objective IKDC, Tegner Activity Level, EQ-5D, VAS for pain and AP laxity assessment with KT-1000 arthrometer. Limb alignment and OA changes were evaluated on radiographs.

Results

All scores significantly improved from pre-operative status to final follow-up. KT-1000 evaluation showed a mean side-to-side difference of 2.2 ± 1.0 mm. Two patients were considered as failures. The mean correction of the limb alignment was 5.6° ± 2.8°. Posterior tibial slope decreased at a mean of 1.2° ± 0.9°. At final follow-up, the mechanical axes crossed the medial–lateral length of tibial plateau at a mean of 56 ± 23 %, with only 1 patient (3 %) presenting severe varus alignment. OA progression was recorded only on the medial compartment (p = 0.0230), with severe medial OA in 22 % of the patients. No patients underwent osteotomy revision, ACL revision, UKA or TKA.

Conclusions

The described technique allowed patients with medial OA, varus alignment and chronic ACL deficiency to restore knee laxity, correct alignment and resume a recreational level of activity at 6.5 years of follow-up.

Level of evidence

Case series with no comparison group, Level IV.     

Medial sixth of the patellar tendon at the tibial attachment is useful for the anterior reference in rotational alignment of the tibial component

Purpose

The anteroposterior (AP) axis connecting the middle of the posterior cruciate ligament to the medial border of the patellar tendon at its attachment has been introduced as a reproducible and reliable reference perpendicular to the surgical epicondylar axis in healthy knees. A recent literature has reported that the AP axis of the tibia is, on average, almost perpendicular to the surgical epicondylar axis also in varus and valgus knees and can be used as a tibial rotational reference to minimize the risk for rotational mismatch between the femoral and tibial components in total knee arthroplasty (TKA). However, it is difficult to identify the AP axis after tibial resection. The purpose of the current study was to determine a modified AP axis that runs parallel to the AP axis and passes through the centre of the cut surface in osteoarthritic knees.

Methods

Preoperative computed tomography scans on 30 varus and 30 valgus knees undergoing TKA were studied using a three-dimensional software. The modified AP axis that runs parallel to the AP axis and passes through the centre of the cut surface was drawn. We investigated where the modified AP axis crossed the patellar tendon at its tibial attachment.

Results

The modified AP axis passed through the medial 1/6 of the patellar tendon (4 mm from medial edge) at its attachment in both varus and valgus knees.

Conclusions

The AP axis of the tibia is useful as a tibial rotational reference in cutting the proximal tibia, but it is difficult to identify the AP axis after tibial resection. The clinical relevance of this study is that medial 1/6 of the patellar tendon at its attachment would be a useful landmark in aligning the tibial component.

Level of evidence

IV.     

Open-wedge high tibial osteotomy: comparison between manual and computer-assisted techniques

Purpose

The purpose of our study was to compare clinical and radiological results of two groups of patients treated for medial compartment osteoarthritis of the knee with either conventional or computer-assisted open-wedge high tibial osteotomy (HTO). Goals of surgical treatment were a correction of the mechanical axis between 2° and 6° of valgus and a modification of posterior tibial slope between ?2° and +2°.

Methods

Twenty-four patients (27 knees) affected by varus knee deformity and operated with HTO were prospectively followed-up. They were randomly divided in two groups, A (11 patients, conventional treatment) and B (13 patients, navigated treatment). The American Knee Society Score and the Modified Cincinnati Rating System Questionnaire were used for clinical assessment. All patients were radiologically evaluated with a comparative lower limb weight-bearing digital radiograph, a standard digital anteroposterior, a latero-lateral radiograph of the knee, and a Rosenberg view.

Results

Patients were followed-up at a mean of 39 months. Clinical evaluation showed no statistical difference (n.s.) between the two groups. Radiological results showed an 86% reproducibility in achieving a mechanical axis of 182°–186° in group B compared to a 23% in group A (p = 0.0392); furthermore, in group B, we achieved a modification of posterior tibial slope between ?2° and +2° in 100% of patients, while in group A, this goal was achieved only in 24% of cases (p = 0.0021).

Conclusion

High tibial osteotomy with navigator is more accurate and reproducible in the correction of the deformity compared to standard technique.

Level of evidence

Therapeutic study, Level II.     

Patella infera or patellar tendon adherence after high tibial osteotomy

Purpose

Alterations in patellar height after high tibial osteotomy are found in many instances. Fibrosis of the tendon is implicated as the cause of the mechanism of patella lowering. This study aimed to determine the relationship between the position of the patella and the histopathological findings at the patellar tendon after high tibial osteotomy.

Methods

Nineteen knees in seventeen patients who were consecutively hospitalised for implant extraction are studied. All of the patients had previously undergone closing wedge osteotomy by the same surgeon at the same department. The median follow-up time is 15 months (range: 11–35). Five patients who all underwent high tibial osteotomy at the same time are also included in the study as a control group for histopathological evaluation. All of the patients are evaluated radiologically, patellar tendon biopsies are taken during the operation, and histopathological analyses are performed.

Results

The shortening of the patellar tendon is statistically significant (P < 0.05). The severity of the vascularisation, inflammation, and fibrotic change observed at the distal part of the tendon is evident. However, there is no statistically significant correlation between these findings and the degree of shortening.

Conclusions

The shortening of the tendon occurs as a result of adherence in the distal part of the tendon. It would appear that it is this shortening that causes the difficulties encountered during arthroplasty surgery of osteotomy patients, and not patella infera.

Level of evidence

Retrospective study, Level II.     

Tibio-femoral and patello-femoral joint kinematics during navigated total knee arthroplasty with patellar resurfacing

Purpose

In total knee arthroplasty, surgical navigation systems provide tibio-femoral joint (TFJ) tracking for relevant bone preparation, disregarding the patello-femoral joint (PFJ). Therefore, the important intra-operative assessment of the effect of component positioning, including the patella, on the kinematics of these two joints is not available. The objective of this study is to explore in vivo whether accurate tracking of the patella can result in a more physiological TFJ and PFJ kinematics during surgery.

Methods

Ten patients underwent navigated knee replacement with patellar resurfacing. A secondary system was used to track patellar motion and PFJ kinematics using a special tracker. Patellar resection plane position and orientation were recorded using an instrumented probe. During all surgical steps, PFJ kinematics was measured in addition to TFJ kinematics.

Results

Abnormal PFJ motion patterns were observed pre-operatively at the impaired knee. Patellar resection plane orientation on sagittal and transverse planes of 3.9° ± 9.0° and 0.4° ± 4.1° was found. A good restoration of both TFJ and PFJ kinematics was observed in all replaced knees after resurfacing, in particular the rotations in the three anatomical planes and medio-lateral patellar translation.

Conclusions

Patella tracking results in nearly physiological TFJ and PFJ kinematics in navigated knee arthroplasty with resurfacing. The intra-operative availability also of PFJ kinematics can support the positioning not only of the patellar component in case of resurfacing, but also of femoral and tibial components.

Level of evidence

II.     

Gradual correction of idiopathic genu varum deformity using the Ilizarov technique

Purpose

Proximal tibial osteotomy is an effective treatment option for genu varum deformity among the many other described techniques. The purpose of this study is to evaluate the clinical and radiological outcomes and the complications in gradual correction of idiopathic genu varum deformity using Ilizarov frame.

Methods

Proximal tibial medial opening wedge osteotomy was performed in 21 lower limbs of 11 patients, with whom the Ilizarov external fixator was used for gradual correction of the varus deformity. The mean age of the patients was 24.8 years (SD, 5.3). Deformity measurements of conventional mechanical axis deviation, mechanical medial proximal tibial angle, mechanical lateral distal femoral angle, posterior proximal tibial angle, joint conversion angle, tibio-femoral angle and tibial slope were compared.

Results

The mean time for removal of the Ilizarov fixator was 24.7 weeks. At the last follow-up, the mean of Hospital for Special Surgery knee score increased, and the mean mechanical medial proximal tibial angle, tibio-femoral angle and conventional mechanical axis deviation improved. The differences between preoperative and postoperative posterior proximal tibial angle, mechanical lateral distal femoral angle, joint conversion angle and tibial slope were not significant. Ten complications were observed, of which 8 were minor complications and 2 were minor complications.

Conclusion

With a few complications, normal alignment and orientation of lower extremity can be established in patients with idiopathic genu varum deformity through gradual correction using a Ilizarov fixator.

Level of evidence

Retrospective case series, Level IV.     

Different changes in slope between the medial and lateral tibial plateau after open-wedge high tibial osteotomy

Purpose

In contrast to radiographic measurements, MRI provides multiple slices of the knee joint in the sagittal plane, making it possible to assess the medial and lateral tibial slope separately. The purpose of this study is to investigate the effect of medial open-wedge high tibial osteotomy (MOWHTO) on bony and meniscal slope in the medial and lateral tibiofemoral compartments. It was hypothesised that greater changes on the medial tibial plateau would be observed compared with the lateral one.

Methods

A retrospective analysis of prospectively collected data was performed on pre- and post-operative MRIs from 21 patients (17 men and 4 women; age 52 ± 9 years). Inclusion criteria were varus alignment, medial compartment osteoarthritis and election for a primary MOWHTO. Each patient had a preoperative and a post-operative high-resolution MRI (3Tesla, Magnetom Trio, Siemens AG) at an average follow-up of 2.1 years. A previously published method was used to measure bony and meniscal slope for each compartment. The difference between pre- and post-operative tibial slope for both compartments was calculated and associated with the amount of frontal correction.

Results

There was a significant increase in bony tibial slope in both compartments following MOWHTO. When a change in bony tibial slope was detected in an individual patient, the change was larger in the medial compartment, with the average change also significantly greater (p < 0.01) in the medial compartment (2.4° ± 1.3°) compared with the lateral compartment (0.9° ± 1.1°). There was also a significant increase (p < 0.01) in the lateral tibial meniscal slope of 0.9° ± 1.4°, which was equivalent to the change in the bony lateral slope. The amount of frontal correction was not significantly associated with the amount of change in slope.

Conclusions

The results suggest that the modification of the bony slope is larger in the medial compartment after MOWHTO, which is likely related to the location of the hinge on the lateral tibial cortex. These findings suggest that consideration of the medial and lateral tibial slope intra-operatively could be important to identify the optimal location of the hinge. However, further studies are required before recommending any modification to the surgical technique, as the potential clinical consequences of tibial slope alterations remain unknown.

Level of evidence

IV.     

Outcome after high tibial open-wedge osteotomy: a retrospective evaluation of 533 patients

Purpose

Open-wedge valgus high tibial osteotomy is a well-established procedure in the management of medial osteoarthritis of the knee. In recent years, improved osteotomy and fixation methods have led to an increased use of this technique. The aim of this study was to identify predictive parameters for the clinical outcome after valgus high tibial osteotomy.

Methods

A multicentre case series involving retrospective capture of baseline data and prospective outcome assessment of patients with knee OA who underwent an osteotomy using Tomofix^® plate was conducted. Functional outcome was assessed using Oxford 12-item Knee Score.

Results

Before surgery, the majority of patients had grade III (52 %) and grade IV (33 %) lesions according to Outerbridge classification. Three hundred and eighty-six of 533 eligible patients were interviewed for follow-up after an average of 3.6 years. The mean Oxford Knee Score was 43 points. Six per cent experienced at least one local postoperative complication. There was a tendency towards lower score results in patients with a higher preoperative degree of the medial cartilage lesion. No correlation between patient age and the Oxford Knee Score was observed.

Conclusion

Being male, being operated by an experienced surgeon, having no intake of pain medication at follow-up and having no postoperative complication are positive predictors of the Oxford Knee Score up to 5 years after surgery. This study reveals favourable midterm results after valgus high tibial osteotomy in varus osteoarthritis, even in older patients with high degree of cartilage damage.

Level of evidence

II.     

High tibial open wedge osteotomy below the tibial tubercle: clinical and radiographic results

Purpose

The purpose of this study was to evaluate the clinical and radiographic results of open wedge HTO below the tubercle for genu varum in relatively young patients.

Methods

Thirty-seven knees in 19 patients with genu varum treated by open wedge HTO below the tubercle between 2001 and 2008 were retrospectively studied. Median follow-up was 36 months (12–108), and median patient age at the time of surgery was 26 years (16–45). Clinical results were evaluated using Lysholm knee scores and Hospital for Special Surgery knee scores. Satisfaction with the results of surgery (0–10 points) was subjectively evaluated using operative scar (1–5 points) and leg shape (1–5 points) results at follow-up. Radiographic evaluations were made using: (1) tibiofemoral angles, (2) mechanical axis deviations, (3) varus-valgus inclinations of the tibial plateau, (4) tibial slopes, and (5) Insall-Savati and (6) Blackburne-Peel ratios.

Results

All but one patient achieved radiographic healing and union at the osteotomy site at an average of 3 months postoperatively. Average Lysholm knee score improved from 89.4 ± 8.7 preoperatively to 98.6 ± 2.5 at final follow-up (P = 0.0001), and mean HSS score improved from 91.1 ± 5.6 preoperatively to 98.5 ± 2.0 at final follow-up (P = 0.0001). Mean patient satisfaction score at final follow-up was 8.6 ± 1.0, and mean tibiofemoral angle increased from ?1.6° preoperatively to 7.7° at final follow-up (P < 0.0001). The point where the mechanical axis crosses the tibial plateau also shifted significantly from 15.0% preoperatively to 50.6% at final follow-up (P = 0.0002). However, mean posterior tibial slope did not change significantly (9.7° preoperatively and 8.7° at final follow-up; P = NS), and neither did patella heights as measured by Insall-Savati and Blackburne-Peel ratios.

Conclusion

Both functional assessment and radiographic measures indicated that HTO below the tibial tubercle leads to significant improvements in radiographic parameters and knee function without changes in patellar height or posterior tibial slope. The results obtained support the hypotheses that opening wedge HTO below the tibial tubercle should be recommended in relatively young patients with genu varum.

Level of evidence

Therapeutic study, Level IV.     

Patellar tilt and thickness do not influence postoperative flexion in a high-flex design total knee arthroplasty

Purpose

The purpose of this short-term study was to determine whether patellar thickness and tilt influence the postoperative flexion in a high-flex design total knee arthroplasty (TKA).

Methods

Between 2007 and 2009, 106 patients underwent surgery for TKA using rotating platform flex prosthesis (DePuy, Warsaw, Ind). All of them were suffering from end-stage osteoarthritis. All patients were evaluated preoperatively and at 12 months of follow-up. Maximum active, non-weight-bearing flexion was the primary outcome parameter. Standard standing antero-posterior and lateral weight-bearing radiographs were made. The patellofemoral joints were evaluated in skyline views taken with the knees at approximately 60° of flexion. Patellar thickness, patellar tilt, Caton–Deschamps indices and lower limb alignment were measured.

Results

The mean flexion observed before surgery was 125° ± 15° and after 1 year was 128° ± 13°. The mean patellar thickness preoperatively was 24.5 ± 2.9 and 25.8 ± 3.2 mm at 12 months after surgery. The mean patellar tilt before the procedure was 2.9° ± 4.1° and after 12 months of follow-up was ?0.8° ± 5.0°. The mean preoperative hip-knee-ankle was 2.6° ± 6.2°. No significant correlation was found between postoperative patellar tilt and thickness and postoperative flexion (n.s.).

Conclusions

Patellar tilt and thickness after TKA are factors that depend on the surgery. The resection of the patella can influence both patellar thickness and patellar tilt. By developing adequate surgical instruments, it would be possible to avoid the occurrence of an exaggerated patellar tilt or a major difference in patellar thickness. However, these two factors did not seem to influence the postoperative flexion in a high-flex design TKA, which can be seen as one of the most important outcome factors after TKA.

Level of evidence

IV.     

Progression of medial compartmental osteoarthritis 2–8 years after lateral closing-wedge high tibial osteotomy

Purpose

The primary purpose of this study is to investigate the progression of medial osteoarthritis (OA) following lateral closing-wedge high tibial osteotomy (HTO). Secondary outcomes included functional and pain scores.

Methods

This prospective cohort study analysed 298 patients treated with lateral closing-wedge HTO surgery for medial compartmental OA. OA progression was measured by comparing the minimum joint space width (mJSW) and Kellgren–Lawrence (KL) score on radiographs preoperatively and postoperatively. The WOMAC score and NRS score for pain were obtained preoperatively and postoperatively to assess secondary outcomes. Failure was defined as revision surgery; survival was estimated.

Results

Mean follow-up was 5.2 ± 1.8 years (range 2–8.5). Mean preoperative mJSW was 3.4 ± 1.6 mm, which changed nonsignificantly (p = 0.51) to 3.4 ± 1.7 mm postoperatively. Mean annual joint space narrowing was 0.02 ± 0.34 mm/year. Progression to 1 KL grade or more was seen in 132 (44 %) patients, and annual risk of KL progression was 8.6 %. No KL progression was seen in 56 % of patients. Mean NRS decreased from 7.3 ± 1.5 to 3.5 ± 2.5 (p < 0.001). WOMAC scores decreased from 48.0 ± 17.2 to 23.6 ± 19.7 (p < 0.001). Failure was seen in 21 patients.

Conclusion

Compared to demographic data in the literature, valgus high tibial osteotomy seems to reduce the progression of OA, reduces pain and improves knee function in patients with medial compartment OA and a varus alignment.

Level of evidence

III.

     

Relationship between the tibial anteroposterior axis and the surgical epicondylar axis in varus and valgus knees

Purpose

Proper rotational alignment in total knee arthroplasty (TKA) is essential for successful outcomes. The surgical epicondylar axis (SEA) has been frequently used to determine the femoral rotational alignment, and the anteroposterior (AP) axis of the tibia described in previous study has been introduced as a line perpendicular to the SEA in healthy knees. However, the rotational relationship between the distal femur and the proximal tibia would vary between normal and osteoarthritic knees, and a question remains whether the rotational relationship between the SEA and the AP axis of the tibia would be the same between normal and osteoarthritic knees. This study aims to determine whether the AP axis of the tibia is actually perpendicular to the SEA and useful for the tibial rotational alignment also in osteoarthritic knees.

Methods

Preoperative computed tomography scans on 25 varus and 25 valgus knees undergoing TKA were studied. The SEA and the AP axis of the tibia were identified using a three-dimensional software, and the angle between the line perpendicular to the projected SEA and the AP axis was measured.

Results

The AP axis of the tibia was 1.7° ± 4.3° and 2.0° ± 4.0° internally rotated relative to the line perpendicular to the SEA in the varus and valgus groups, respectively.

Conclusions

The AP axis of the tibia was, on average, perpendicular to the SEA in both varus and valgus knees. The AP axis would be useful for setting the tibial component with minimal rotational mismatch.

Level of evidence

IV.     

Tibial rotational osteotomy and distal tuberosity transfer for patella subluxation secondary to excessive external tibial torsion: surgical technique and clinical outcome

Purpose

Recurrent patella subluxation may be secondary to excessive external tibial torsion. The purpose of this study is to evaluate the clinical and radiographic outcome of patients undergoing tibial derotation osteotomy and tibial tuberosity transfer for recurrent patella subluxation in association with excessive external tibial torsion.

Methods

A combined tibial derotation osteotomy and tibial tuberosity transfer was performed in 15 knees (12 patients) with recurrent patella subluxation secondary to excessive external tibial torsion. Clinical evaluation was carried out using preoperative and post-operative Knee Society Score (KSS), Kujala Patellofemoral score, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire, the short form-12 (SF-12) and a visual analogue score (VAS) pain scale.

Results

The median follow-up period was 84 months (range 15–156) and median patient age was 34 years (range 19–57 years). The median preoperative external tibial torsion was 62° (range 55°–70°), with a median rotational correction of 36° (range 30°–45°) after surgery. Significant improvement (p < 0.05) was found in the KSS part I (37 ± 14 to 89 ± 11 points), KSS part II (25 ± 26 to 85 ± 14 points), Kujala score, the SF-12 outcome, WOMAC score and VAS score (8.8 ± 1.9 to 2.4 ± 1.5). Two patients had a nonunion of the tibial osteotomy site; one patient required bone grafting, while another patient required revision to total knee arthroplasty.

Conclusion

Patients presenting with recurrent patella subluxation secondary to excessive external tibial torsion >45° who underwent tibial derotation osteotomy and tibial tuberosity transfer achieved a satisfactory outcome in terms of pain relief and improved function. A significant complication was seen in 2/15 patients.

Level of evidence

Case series, Level IV.     

Influence of tibial slope asymmetry on femoral rotation in patients with lateral patellar instability

Purpose

The geometry of the tibial plateau and its influence on the biomechanics of the tibiofemoral joint has gained increased significance. However, no quantitative data are available regarding the inclination of the medial and lateral tibial slope in patients with patellar instability. It was therefore the purpose of this study to evaluate tibial slope characteristics in patients with patellar dislocations and to assess the biomechanical effect of medial-to-lateral tibial slope asymmetry on lateral patellar instability.

Methods

Medial and lateral tibial slope was measured on knee magnetic resonance images in 107 patients and in 83 controls. The medial-to-lateral tibial slope asymmetry was assessed as the intra-individual difference between the medial and lateral tibial plateau inclination considering severity of trochlear dysplasia. The effect of tibial slope asymmetry on femoral rotation was calculated by means of radian measure.

Results

Severity of trochlear dysplasia was significantly associated with an asymmetric inclination of the tibial plateau. Whereas the medial tibial slope showed identical values between controls and study patients (n.s.), lateral tibial plateau inclination becomes flatter with increasing severity of trochlear dysplasia (p < 0.01). Consequently, the intra-individual tibial slope asymmetry increased steadily (p < 0.01) and increased internal femoral rotation in 20° and 90° of knee flexion angles in patients with severe trochlear dysplasia (p < 0.01). In addition, the extreme values of internal femoral rotation were more pronounced in patients with patellar instability, whereas the extreme values of external femoral rotation were more pronounced in control subjects (p = 0.024).

Conclusion

Data of this study indicate an association between tibial plateau configuration and internal femoral rotation in patients with lateral patellar instability and underlying trochlear dysplasia. Thereby, medial-to-lateral tibial slope asymmetry increased internal femoral rotation during knee flexion and therefore might aggravate the effect of femoral antetorsion in patients with patellar instability.

Level of evidence

III.     

Patellar thickness and lateral retinacular release affects patellofemoral kinematics in total knee arthroplasty

Purpose

To study the effect of increasing patellar thickness (overstuffing) on patellofemoral kinematics in total knee arthroplasty and whether subsequent lateral retinacular release would restore the change in kinematics.

Methods

The quadriceps of eight fresh-frozen knees were loaded on a custom-made jig. Kinematic data were recorded using an optical tracking device for the native knee, following total knee arthroplasty (TKA), then with patellar thicknesses from ?2 to +4 mm, during knee extension motion. Staged lateral retinacular releases were performed to examine the restoration of normal patellar kinematics.

Results

Compared to the native knee, TKA led to significant changes in patellofemoral kinematics, with significant increases in lateral shift, tilt and rotation. When patellar composite thickness was increased, the patella tilted further laterally. Lateral release partly corrected this lateral tilt but caused abnormal tibial external rotation. With complete release of the lateral retinaculum and capsule, the patella with an increased thickness of 4 mm remained more laterally tilted compared to the TKA with normal patellar thickness between 45° and 55° knee flexion and from 75° onwards. This was on average by 2.4° ± 2.9° (p < 0.05) and 2.°9 ± 3.0° (p < 0.01), respectively. Before the release, for those flexion ranges, the patella was tilted laterally by 4.7° ± 3.2° and 5.4° ± 2.7° more than in the TKA with matched patellar thickness.

Conclusion

Patellar thickness affects patellofemoral kinematics after TKA. Although lateral tilt was partly corrected by lateral retinacular release, this affected the tibiofemoral kinematics.

Level of evidence

IV.     

Early weight bearing versus delayed weight bearing in medial opening wedge high tibial osteotomy: a randomized controlled trial

Purpose

The need for a period of non-weight bearing after medial opening wedge high tibial osteotomy remains controversial. It is hypothesized that immediate weight bearing after medial opening wedge high tibial osteotomy would have no difference in functional scores at one year compared to delayed weight bearing.

Methods

Fifty patients, median age 54 years (range 40–65), with medial compartment osteoarthritis, underwent a medial opening wedge high tibial osteotomy utilizing a locking plate without bone grafting. Patients were randomized into an Immediate or a Delayed (2 months) weight bearing group. All patients were assessed at one-year follow-up and the two groups compared. The primary outcome measure was the IKS score. Secondary outcome measures included the IKDC score, the VAS pain score and rate of complications.

Results

The functional scores significantly improved in both groups. The IKS score increased from 142 ± 31 to 171 ± 26 in the Immediate group (p < 0.001) and from 148 ± 22 to 178 ± 23 in the Delayed group (p < 0.001). The IKDC score increased from 49 ± 17 pre-operatively to 68 ± 14 one-year post-operatively in the Immediate group (p < 0.0001) and from 44 ± 16 to 69 ± 19 in the Delayed group (p < 0.001). The average VAS for pain 2 months after surgery was 3 ± 3 in the Immediate group and 3 ± 2 in the Delayed (n.s.). There was no significant difference between the two groups in any of the outcome measures. The mean mechanical femorotibial angle changed from 6° of varus (0°–15° of varus, SD = 3°) to 4° of valgus (5°–11° of valgus, SD = 3°) in the Immediate group and from 5° of varus (0°–10° of varus, SD = 3°) to 3° of valgus (2° of varus to 8° of valgus, SD = 3°) in the Delayed group. No difference was seen between groups, and no loss of correction was observed in any patient. Two cases of non-union occurred, one in each group. One infection and one deep vein thrombosis occurred in the Immediate group.

Conclusion

Immediate weight bearing after medial opening wedge high tibial osteotomy had no effect on functional scores at 1 year follow-up and did not significantly increase the complication rate. Immediate weight bearing after medial opening wedge high tibial osteotomy appears to be safe and can allow some patients a quicker return to activities of daily living and a decreased convalescence period.

Level of evidence

II.