High tibial osteotomy for varus gonarthrosis: a 10- to 24-year follow-up study

High survivorship and low complication rate in a single-centre series of 651 medial opening wedge high tibial osteotomy cases with a mean follow-up of 13 years

PURPOSE

This study aimed to report the early to midterm results of medial opening wedge high tibial osteotomy (MOWHTO) from the largest single-centre osteotomy database. The primary outcomes were reporting the radiological corrections and the functional outcomes represented by multiple patient-reported outcome measures (PROMs). The secondary outcomes were to report the complications, revisions and survivorship up to 10 years postoperatively.

METHODS

A prospectively maintained single-centre database of 1138 knee osteotomies was retrospectively reviewed. Patients who underwent MOWHTO and met the inclusion criteria were included. Those inclusion criteria were moderate to severe knee pain that failed conservative management; varus knee malalignment; and isolated medial osteoarthritis of the knee. A total of 651 cases, with a mean age of 46.7 ± 9 years and a mean body mass index of 29.6 ± 5.2 kg/m2 , were included. This comprised 71% males (n = 462) and 29% females (n = 189). The mean follow-up was 158.1 ± 45.4 months. Multiple PROMs were recorded preoperatively and serially postoperatively. This included the Knee injury and Osteoarthritis Outcome Scores, the Oxford Knee Score, the Oxford Knee Score-Activity and Participation Questionnaire, the Western Ontario and McMaster University Scores, the Visual Analogue Scale for health and pain, and the EQ-5D, which is a standardised measure of health-related quality of life. All lower limb alignment measurements were recorded pre- and postoperatively. The rates of osteotomy revision, conversion to arthroplasty, complications, and 5- and 10-year survivorship were recorded.

RESULTS

A total of 651 cases were followed up to a mean of 158.1 ± 45.4 months. The mean planned correction angle was 7.6° ± 2.9°. The mean planned opening wedge distance was 8.1 ± 3.1 mm. The mean intraoperative anterior and posterior osteotomy gaps opening were 7.7 ± 3.4 and 8.9 ± 3.8 mm, respectively. Postoperatively, the mean mechanical tibiofemoral angle improved from -5.7° ± 2.9° varus to 1.3° ± 2.5° valgus, the mean medial proximal tibial angle improved from preoperative 85.5° ± 2.3° to postoperative 91.6° ± 2.7° and the mean Mikulicz point improved from 21.7 ± 12.6% to 54.8 ± 11% (all p values < 0.001). All PROMs significantly improved at 24 months follow-up (all p values < 0.001). The rate of osteotomy revision was 1.1% at a mean of 2 ± 2.5 years postoperatively. The overall rate of arthroplasty conversion was 9.1%. This comprised 5.8% total knee arthroplasty conversion at a mean of 6.9 ± 3.5 years postoperatively and 3.2% unicompartmental knee arthroplasty conversion at a mean of 5.7 ± 2.5 years postoperatively. An overall 10.3% complication rate was recorded. The 5 and 10-year survivorship was 97.2% and 91.9%, respectively.

CONCLUSION

MOWHTO is a radiologically and clinically rewarding procedure with a high survival rate at 5 and 10 years and a low complication rate in experienced hands. MOWHTO should be considered in patients presenting with medial unicompartmental knee pain with an evidence of overload and a varus mechanical coronal plane axis.

LEVEL OF EVIDENCE

Level IV, retrospective cohort study.

Good long-term survival and patient-reported outcomes after high tibial osteotomy for medial compartment osteoarthritis

The lateral closing and medial opening wedge high tibial osteotomy can correct a varus malalignment of the knee caused by medial compartment osteoarthritis. These procedures have produced great short-term and mid-term results. As no systematic review has examined their long-term results yet, the goal of this article was to compare the results of all articles about lateral closing and medial opening wedge high tibial osteotomies, published after the year 2000, with a mean follow-up of more than 10 years. A systematic search of the Medline, Web of Science and Cochrane databases resulted in the inclusion of 30 articles. All these studies combined examined the results of 7087 high tibial osteotomies in a total of 6636 patients after a mean follow-up of more than 10 years. Primary outcome measures were the survival rate of the osteotomy, functional scores, patient satisfaction and pain scores. Secondary outcome measures were alignment correction and the identification of factors influencing the survival of the osteotomy. The 5-year, 10-year, 15-year and 20-year survival rates, respectively, ranged from 86 to 100%, 64-97.6%, 44-93.2% and 46-85.1%. The subjective scoring systems showed an improvement postoperatively that was maintained until final follow-up. The anatomical and mechanical tibiofemoral axis were, respectively, corrected to a mean of 7.3°-13.8° of valgus and 0.6°-4° of valgus. The results of the articles evaluating the influence of potential risk factors were contradictory. Despite the low quality of the available evidence, the lateral closing and medial opening wedge high tibial osteotomy seem to remain valid long-term treatment options for patients with painful varus malalignment caused by isolated medial compartment osteoarthritis of the knee. The available results indicate that the need for arthroplasty could be delayed for more than 15 years in the majority of patients. However, higher-quality studies are needed to confirm these findings. As a systematic review is assigned a level of evidence equivalent to the lowest level of evidence used from the analyzed manuscripts, the level of evidence of this systematic review is IV.

Changes in knee joint line orientation after high tibial osteotomy are the result of adaptation of the lower limb to the new alignment

BACKGROUND

Changes in knee joint line orientation (KJLO) resulting in excessive joint line obliquity are a well-known consequence of high tibial osteotomy (HTO) procedures and could lead to degenerative changes. The precise effect of the correction on final KJLO changes is poorly understood. The goal of this study was to identify radiographical parameters that could help to explain the size of KJLO changes after HTO surgery.

METHODS

A total 117 HTO patients were radiographically examined preoperatively and three months postoperatively. Radiographic parameters were KJLO, medial proximal tibial angle (MPTA), hip-knee angle (HKA), mechanical lateral distal femoral angle (mLDFA), lateral distal tibial angle (LDTA), knee joint line congruence angle (KJLCA), ankle joint line congruence angle (AJLCA) and ankle joint line orientation (AJLO). Four new radiographic parameters were introduced to describe knee and foot position on long-leg X-ray: malleolar distance to midline (MDTM), intermalleolar distance (IMD), condylar distance to midline (CDTM) and intercondylar distance (ICD). Correlations of these parameters and changes in KJLO were assessed.

RESULTS

Strong correlations are found between KJLO changes and MDTM (r = 0.709), IMD (r = 0.691), CDTM (r = 0.711) and ICDM (r = 0.702), in contrast to weak correlations between changes in KJLO and MPTA (r = -0.342). These results suggest an important impact of foot and knee position changes on the final alteration of KJLO after HTO.

CONCLUSIONS

The final change of KJLO after HTO is the effect of adaptation of the lower limb, which is driven by the (maximum) alterations of foot and knee position rather than the size of correction of the procedure.

Plate-related results of opening wedge high tibial osteotomy with a carbon fiber reinforced poly-ether-ether-ketone (CF-PEEK) plate fixation: a retrospective case series of 346 knees

BACKGROUND

While open wedge high tibial osteotomy (owHTO) is an established standard procedure to treat medial osteoarthritis of the knee in combination with varus deformity, it bears the risk of postoperative hardware failures and lateral cortical hinge fractures. This in turn can lead to an accelerated osteoarthritis, non-union, or a loss of correction accuracy. The purpose of the study was to evaluate the radiologic outcomes of owHTO with a carbon fiber reinforced poly-ether-ether-ketone (CF-PEEK) plate fixation in patients with medial osteoarthritis and varus deformity.

METHODS

Three hundred twenty-four consecutive patients (346 knees) who were treated with owHTO using the PEEKPower HTO plate were included in this retrospective study; 89.9% of the patients were overweight or obese. Patients were followed by conventional radiographs over a 12-month period. Typical plate-related results such as the time and quality of gap healing as well as the correction accuracy were analyzed. Furthermore, the number of lateral cortex fractures was determined.

RESULTS

Bony consolidation was observed after a mean gap healing time of 4.0 ± 1.7 months independent on the patients' weight (p = 0.2302). With increasing gap sizes, bony healing was significantly prolonged (p < 0.001). Additionally, patients with greater gap sizes had a significantly increased risk for a lateral cortex fracture (p = 0.0041). However, none of the patients had a non-union 1 year postoperative. A hinge fracture occurred in 30% of patients. Hinge fractures with Takeuchi grades I and II increased the gap healing time compared to no fracture (p = 0.0069 and p = 0.0002, respectively), but only 1.2% of patients with hinge fracture had a clinical relevant loss of correction ≥ 3 mm. No implant failures were found.

CONCLUSIONS

Open wedge HTO using the PEEKPower HTO plate for patients with medial osteoarthritis of the knee in combination with tibial varus deformity leads to excellent bony consolidation also in cases with a hinge fracture, a gap size > 12 mm as well as for severely obese patients.

The efficacy and safety of opening-wedge high tibial osteotomy in treating unicompartmental knee osteoarthritis: Protocol for a systematic review and meta-analysis

BACKGROUND

High tibial osteotomy (HTO) is an effective surgical technique that can stop or inhibit the progression of unicompartmental knee osteoarthritis (KOA) to avoid or postpone the need for knee arthroplasty in patients. Whether opening-wedge high tibial osteotomy (OWHTO) is superior to closing-wedge high tibial osteotomy (CWHTO) in treating unicompartmental KOA remains controversial.

METHODS

Databases (Cochrane Library, EMBASE, and PubMed) were searched from their establishment to July 1, 2018 for randomized controlled trials comparing the application of OWHTO to CWHTO in patients with unicompartmental KOA. The methodological quality of each included study was assessed according to the Cochrane Handbook for Systematic Reviews of Interventions guideline. Review Manager 5.3.5 software (Cochrane Collaboration, Oxford, UK) was used to synthesize the final results.

RESULTS

The results will provide useful information about the effectiveness and safety of OWHTO in patients with unicompartmental KOA.

CONCLUSION

The findings of the study will be published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD4201811805.

What Determines the Success of Closed-Wedge High Tibial Osteotomy: Severity of Malalignment, Obesity, Follow-up Period, or Age?

Objectives:

High tibial osteotomy (HTO) is a well-established procedure for the treatment of medial knee osteoarthritis originating from malalignment of the lower extremity. The current study was designed to evaluate the clinical and radiographic results of closed-wedge HTO for the treatment of medial knee osteoarthritis and to reveal factors affecting the outcome.

Methods:

A retrospective study was conducted with 138 patients who were operated on for medial knee osteoarthritis between 2000 and 2007 using closed-wedge HTO. Preoperative and follow-up physical examination findings, body mass index (BMI) values, and Hospital for Special Surgery (HSS) and Lysholm knee scores were reviewed. Radiographic evaluation included measurement of the mechanical axis preoperatively and the most recent follow-up orthoroentgenograms. The follow-up knee scores were evaluated according to preoperative mechanical axis, obesity, age, follow-up period, and gender of the patient. The mechanical axis measurement was assessed based on obesity, age, and follow-up period.

Results:

The mean preoperative and latest follow-up mechanical axis was 4.92^o±4.24^o varus and 3.43^o±3.74^o valgus, respectively (p=0.0001). Improvement in the Lysholm (p=0.0001) and HSS (p=0.0001) knee scores was significant. The preoperative mechanical axis, obesity, follow-up period, and gender had no negative effect on the follow-up knee scores, whereas a preoperative age over 50 years had a negative effect on the follow-up knee score. Obesity and the length of the postoperative follow-up period did not have a negative effect on the postoperative mechanical axis, whereas a preoperative age over 50 had a negative effect on the postoperative mechanical axis.

Conclusion:

The results of this study suggest that medial knee osteoarthritis may be treated successfully with closed-wedge HTO. The analysis indicated that factors such as obesity, the degree of preoperative deformity, and gender do not adversely affect the success of treatment. However, a preoperative age over 50 adversely affected the outcome.

Valgus Stress Radiographs Predict Lateral-Compartment Cartilage Thickness but Not Cartilage Degeneration in Varus Osteoarthritis

BACKGROUND

Intact cartilage in the lateral compartment is an important requirement for medial unicompartmental knee arthroplasty. This study sought to determine how measurements of joint space width in the lateral compartment on valgus stress radiographs compare to cartilage thickness as measured with a precise needle test, and whether cartilage thickness is a predictor of cartilage degeneration.

METHODS

A consecutive series of 100 knees undergoing total knee arthroplasty for end-stage varus osteoarthritis was studied. Twenty-eight knees were retrospectively excluded because not all data were available, leaving 72 knees (61 patients; mean age, 67 years [49-87]). On calibrated valgus stress radiographs, lateral-compartment joint space width was measured. During surgery, osteochondral samples of the distal lateral femur and the lateral tibia plateau were harvested. Cartilage thickness and histology were assessed. Cartilage thickness of tibia and femur was defined as lateral-compartment cartilage thickness.

RESULTS

Lateral-compartment joint space width on valgus stress radiographs and lateral-compartment cartilage thickness correlated well (r_s = 0.671, P < .001). However, no correlation of cartilage histology according to the osteoarthritis cartilage histopathology assessment system, and cartilage thickness on the lateral tibia plateau (r_s = -0.060, P = .614) and cartilage thickness on the distal lateral femur (r_s = -0.128, P = .282) was observed.

CONCLUSION

Valgus stress radiographs can assess combined cartilage thickness in the lateral compartment of the knee. Cartilage thickness, however, is a poor predictor of cartilage degeneration.

Thoracic limb alignment in healthy labrador retrievers: evaluation of standing versus recumbent frontal plane radiography

OBJECTIVE

To report thoracic limb alignment values in healthy dogs; to determine if limb alignment values are significantly different when obtained from standing versus recumbent radiographic projections.

STUDY DESIGN

Prospective cross-sectional study.

ANIMALS

Labrador Retrievers (n = 45) >15 months of age.

METHODS

Standing and recumbent radiographs were obtained and limb montages were randomized before analysis by a single investigator blinded to dog, limb, and limb position. Twelve limb alignment values were determined using the CORA methodology. Measurements were performed in triplicate and intra-observer variability was evaluated by intra-class correlation coefficient (ICC). Limb alignment values were reported as mean ± SD and 95% confidence intervals. Linear mixed models were used to determine if significant associations existed between limb alignment values and limb, limb position, gender, age, weight, and body condition score.

RESULTS

There were significant differences in standing and recumbent limb alignment values for all values except elbow mechanical axis deviation (eMAD). Limb, gender, age, body weight, and body condition score had no effect. ICC values ranged from 0.522 to 0.758, indicating moderate to substantial agreement for repeated measurements by a single investigator.

CONCLUSIONS

Limb alignment values are significantly different when determined from standing versus recumbent radiographs in healthy Labrador Retrievers.

Survival and clinical outcome of isolated high tibial osteotomy and combined biological knee reconstruction

PURPOSE

We sought to determine survival and clinical outcomes of high tibial osteotomy (HTO) with or without articular cartilage surgery and/or meniscal allograft transplantation in patients with medial compartment chondral pathology, varus malalignment, and/or meniscal deficiency, whether there is any difference in survival or clinical outcome between these patient cohorts, and whether there is any difference between opening- (OWHTO) and closing-wedge (CWHTO) techniques.

METHODS

A systematic review of multiple medical databases was performed using PRISMA guidelines. Study quality was assessed via modified Coleman Methodology Scores (MCMS).

RESULTS

Sixty-nine studies were included (4557 subjects). MCMS rating was overall poor. Mean follow-up was 7.1 years. Mean subject age was 53 years. Survival of isolated HTO was 92.4%, 84.5%, 77.3%, and 72.3% at 5, 10, 15, and 20 years of follow-up. At 5 years of follow-up, HTO with articular cartilage surgery had significantly greater survival (97.7%) than either isolated HTO (92.4%) or HTO with MAT (90.9%). Isolated HTO, HTO with articular cartilage surgery, and HTO with MAT all significantly improved subjective and objective clinical outcome scores. At two years of follow-up, survival was significantly greater following OWHTO (98.7%) versus CWHTO (96.7%). However, at all other time points with or without combined articular cartilage surgery and/or MAT, there was no significant survival difference between the techniques.

CONCLUSIONS

Survival and clinical outcomes of isolated HTO were excellent at short- and mid-term follow-ups, but deteriorated with time. HTO with concomitant procedures also demonstrated excellent early survival and clinical outcomes that deteriorated with time (up to 10 years).

The impact of a high tibial valgus osteotomy and unicondylar medial arthroplasty on the treatment for knee osteoarthritis: a meta-analysis

PURPOSE

Both high tibial valgus osteotomy (HTO) and unicompartmental medial knee arthroplasty (UKA) are established methods for the treatment for moderate stages of OA. This is the first global meta-analysis to compare the long-term effects of both methods regarding survival, outcomes and complications of total arthroplasty.

METHODS

Literature research was performed using established medical databases: MEDLINE (via PubMed), EMBASE (via OVID) and the Cochrane register. Criteria for inclusion were as follows: English or German papers, a clinical trial with a clear description of survival, an outcome evaluation using a well-described knee score and a follow-up >5 years. Statistical analysis was performed using the special meta-analysis software called "Comprehensive Meta Analysis" (version 2.0; Biostat, Englewood, NJ, USA).

RESULTS

Final meta-analysis after the full-text review included 46 studies about valgus HTO and 43 studies about medial UKA. There were no significant differences between valgus HTO and medial UKA in terms of the number of total required replacements. After a 5- to 8-year follow-up, 91.0% of the valgus HTO patients and 91.5% of medial UKA patients did not need a total replacement. This value was 84.4% for valgus HTOs and 86.9% for medial UKAs after a 9- to 12-year follow-up. Mean survival time to TKA was 9.7 years after valgus HTO and 9.2 years after medial UKA. Clinical outcome was significantly better after medial UKA in a 5- to 12-year follow-up. After more than 12 years, results were comparable in both groups. No significant differences were seen in the complication rates.

CONCLUSIONS

This meta-analysis aimed to find the advantages and disadvantages of two established methods for the treatment for medial compartment knee osteoarthritis. Valgus HTO is more appropriate for younger patients who accept a slight decrease in their physical activity. Medial UKA is appropriate for older patients obtaining sufficient pain relief but with reduced physical activity.

LEVEL OF EVIDENCE

II.

Age does not influence the clinical outcome after high tibial osteotomy

PURPOSE

Valgus high tibial osteotomy (HTO) is an established procedure for the medial gonarthrosis. In several studies, many negative influencing factors were evaluated. However, until now, the factor "age" was examined only insufficiently. The aim of our study was to evaluate the factor age in predicting the functional outcome after HTO, and we hypothesized that valgus HTO leads to equal results in the treatment of varus osteoarthritis independent of the patient's age.

METHODS

We could generate 13 pairs of patients with a median age at operation of 57 (55-63) years (group A) versus patients 15 years younger with a median age of 42 (39-47) years (group B). The patients were matched according to the following criteria: age, gender, operation/osteosynthesis method, body mass index, same additional operations, and follow-up time. Evaluation of the patients was done by use of the Tegner and Lysholm score and visual analogue scale (VAS) as well as by subjective satisfaction of the patients.

RESULTS

The Lysholm score showed a significant improvement in group A from 41 (SD ± 12.3) to 65 (SD ± 23.8) points (p = 0.01) and in group B from 33 (SD ± 16.7) to 70 (SD ± 31.8) points (p = 0.007). Moreover, the VAS decreased significantly in group A from 77 (SD ± 15.3) to 36 (SD ± 21.3) points (p = 0.003) and in group B from 73 (SD ± 22.7) to 41 (SD ± 33.7) points (p = 0.02). However, there was no significant difference for both groups regarding the activity of the patients evaluated by the Tegner score (group A: preop.: 5 (1-9), follow-up: 3.5 (1-6); group B: preop.: 6 (3-9), follow-up: 4 (2-7)). Furthermore, there was no significant difference between both groups in view of the Lysholm, Tegner and VAS.

CONCLUSION

Valgus high tibial osteotomy is an effective procedure for the treatment of medial gonarthrosis independent of the patient's age. As a consequence, the age of the patient does not have to be taken into consideration for the indication of high tibial osteotomy.

LEVEL OF EVIDENCE

III.

High tibial osteotomy in young adults with constitutional tibia vara

Frontal plane malalignment of the lower extremity results in abnormal load distribution across the knee joint. Consequences of this increased stress may lead to compartmental osteoarthritis. High tibial osteotomy is well established for early osteoarthritis of the knee joint in middle-aged patients. We hypothesize that earlier realignment of the varus knee can be performed without undue risks and debilitation toward the young active patient and with good results in short-term follow-up. Open-wedge high tibia osteotomy using the Puddu plate was performed on eleven patients (19 knees) under 25 years of age for constitutional high tibia vara. The mechanical femorotibial angle (FTA) and Knee Society Knee Score (KSKS) were compared pre-operatively and 24 months post-operatively. The average FTA improved from +8.8 degrees (+5 - +16) to -0.1 (-2 - +5). The average KSKS improved from 74 (50-100) to 93 (60-100) and the function score improved from 84 (50-100) to 95 (60-100). Special concerns in this age group include unsightly cosmesis, and kneeling pain and discomfort. Open-wedge high tibia osteotomy provides a satisfactory solution for constitutional high tibia vara with minor morbidity on behalf of the patient in the short-term follow-up period.

Correction accuracy and collateral laxity in open versus closed wedge high tibial osteotomy. A one-year randomised controlled study

In a randomised clinical trial in 50 patients with symptomatic osteoarthritis of the medial compartment of the knee, the clinical results of high tibial osteotomy (HTO) according to the open wedge osteotomy (OWO) and closed wedge osteotomy (CWO) were compared. In both groups locked plate fixation was used. Clinical and radiological assessments were performed preoperatively and after one year. Postoperative hip-knee-ankle (HKA) correction angles were monitored on standing leg X-rays. The effect of HTO on collateral laxity of the knee was measured with a specially designed varus-valgus device. The WOMAC osteoarthritis index, the modified knee society score (KS) and visual analogue scales (VAS) were used to assess symptoms of osteoarthritis, function, pain and patient satisfaction. At one-year follow-up we found accurate corrections in both groups and the planned correction angles were achieved. No loss of correction was observed. Furthermore, the medial collateral laxity and the patellar height significantly decreased after OWO. Significant improvements of WOMAC and KS scores were found in both groups. All patients had significantly less pain and were very satisfied with the results. Surgery time was significantly longer in the CWO group, and complications were more frequent in this group. Both techniques led to good and comparable clinical results. The choice of whether to perform an open or a closed wedge osteotomy may be based on preoperative patellar height or concomitant collateral laxity.

Sporting activity after high tibial osteotomy for the treatment of medial compartment knee osteoarthritis

BACKGROUND

Isolated varus osteoarthritis of the knee is a common problem in patients engaged in sports and recreational activities.

HYPOTHESIS

Patients will be able to resume sporting activity after high tibial osteotomy.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 65 patients were surveyed by postal questionnaires to determine their sporting and recreational activities at an average of 36 +/- 8.1 months (range, 14-84) after high tibial osteotomy for the treatment of medial compartment knee osteoarthritis. The clinical evaluation included the Lysholm score, the Tegner activity scale, the Activity Rating Scale, and a visual analog scale for pain.

RESULTS

At the time of survey, 90.9% of patients were engaged in sports and recreational activities, compared with 87.9% before surgery (P = .182). The number of different sporting activities declined from 3.5 preoperatively to 3.0 after surgery (P = .178). The sports frequency per week (2.1 sessions) and the activity duration per week (4.1 hours) did not significantly change from preoperative to postoperative (2.3, P = .211; and 4.2 hours, P = .709, respectively). The Lysholm score (42.4) and the visual analog scale (6.9) illustrated significant improvements (69.6, P = .001; and 2.9, P < .001, respectively). No patient returned to competitive sports after surgery, and declines were noted in the Tegner (4.9 +/- 2.3 to 4.3 +/- 1.5, P < .05) and Activity Rating Scale (5.7 +/- 5.2 to 3.3 +/- 4.6, P = .001) scores. After surgery, many patients continued to engage in high-level activities such as downhill skiing or mountain biking.

CONCLUSION

High tibial osteotomy for the treatment of medial compartment knee osteoarthritis in the active patient demonstrated favorable clinical results and allowed patients to return to sports and recreational activities similar to the preoperative level.

Resorbability of rigid beta-tricalcium phosphate wedges in open-wedge high tibial osteotomy: a retrospective radiological study

The open-wedge high tibial osteotomy (OWHTO) is a well accepted treatment modality for patients with osteoarthritis of the medial compartment associated with genu varum. To fill in the osteotomy gap 30% macroporosity rigid beta-tricalcium phosphate (beta-TCP) is frequently used as a stable resorbable bone substitute. However, the resorbability of these beta-TCP wedges is not known. The aim of this study was to investigate this. Twenty-one OWHTO procedures in seventeen patients were performed with the use of 30% macroporosity rigid beta-TCP wedges. The osteotomies were fixed using an angle-stable locking plate. Conventional AP and lateral radiographs were examined in order to assess the resorbability of the 30% macroporosity rigid beta-TCP wedges as a function of time. A radiological classification system consisting of five phases was used to monitor the resorption of the 30% macroporosity rigid beta-TCP wedges. The mean duration of follow-up was 62 months (+/-23 range of 28-99). In all 21 cases, remnants of the 30% macroporosity rigid beta-TCP wedges were still present at maximum follow-up. Although the boundaries between 30% macroporosity rigid beta-TCP wedges and bone remained slightly visible, all osteotomies were completely consolidated and full osseointegration took place. In 16 out of 21 knees the fixation system was removed after a mean duration of 32 months (+/-19 range of 6-62). In six out of 21 knees a conversion to a knee arthroplasty was performed after a mean duration of 56 months (+/-18 range of 37-82). The OWHTO did not interfere with the placement of knee prostheses. Complete resorption of 30% macroporosity rigid beta-TCP wedges did not take place up to 8 years after operation.

High tibial osteotomy using two threaded pins and figure-of-eight wiring fixation for medial knee osteoarthritis: 14 to 24 years follow-up results

BACKGROUND

High tibial osteotomy (HTO) is an established surgical treatment for medial knee osteoarthritis (OA). Several studies have reported the deterioration of clinical results with time, especially after more than 10 years. The purpose of this study was to evaluate the long-term results after HTO using our originally developed fixation method and to clarify the factors affecting the long-term clinical outcome.

METHODS

Sixty-eight HTO treatments in 55 patients were evaluated. Eighteen patients were unable to be analyzed, thus reducing the study to 48 knees in 37 patients. The follow-up rate of the knee joint was 70.6% and the mean follow-up period was 17.1 years. The first evaluation was performed at a mean of 6.5 years postoperatively, and the most recent evaluation was done at more than 10 years postoperative follow-up. A closing-wedge osteotomy was performed, and the osteotomy site was fixed with two threaded pins and a figure-of-eight wiring technique. The Japanese Orthopaedic Association knee rating score (JOA score) was used for the clinical assessment. The change of the femorotibial angle (FTA) and progression of knee OA were radiographically analyzed. The whole knees were subsequently divided into two groups, satisfactory group and unsatisfactory group, according to the JOA score at the most recent follow-up.

RESULTS

The mean JOA score was 59.1 before HTO and 83.1 at the most recent evaluation. In comparing the satisfactory and unsatisfactory groups, the JOA score before HTO was the same, but the JOA score of the unsatisfactory group was significantly lower at the first evaluation. The FTA in the unsatisfactory group was the same as in the satisfactory group preoperatively, but it was significantly larger after HTO. The radiographic OA was significantly progressed at the most recent evaluation, but no difference was observed in the distribution of the preoperative OA grade between the two groups.

CONCLUSIONS

HTO with two threaded pins and figure-of-eight wiring fixation showed an acceptable clinical outcome, but careful attention was needed for correction loss in early postoperative periods. In addition, the proper correction angle is necessary in order to achieve satisfactory long-term results.

Twenty-year results of combined meniscal allograft transplantation, anterior cruciate ligament reconstruction and advancement of the medial collateral ligament

The purpose of this study was to determine the objective and subjective long-term outcomes of the first free meniscal allograft transplantations in five patients with complete absence or non-repairable lesion of the medial meniscus after 20 years. Between 1984 and 1986 five patients underwent concomitant medial meniscal transplantation with a deep frozen meniscal allograft, ACL reconstruction and femoral advancement or temporary detachment of the MCL. The clinical outcome of the patients was evaluated 20 years postoperatively using clinical assessment, Lysholm-score, KOOS, IKDC-score, radiographs and magnetic resonance imaging. The Lysholm-score ranged between 21 and 97 points of 100 maximal available points. Corresponding to this the total KOOS ranged between 28.4 and 91.1%. The results of the IKDC-score were evaluated as nearly normal (B) (n = 2), abnormal (C) (n = 2) and severely abnormal (D) (n = 1). The radiological evaluation according to the Kellgren-Lawrence classification showed an increase of the degenerative changes between one and four grades. The radiological results revealed clear degenerative changes with long-term follow-up after meniscal allograft transplantation even though some patients did relatively well regarding the subjective and clinical results in the 20-year follow-up examination in comparison with the literature. Despite these relative clear results the question if medial meniscal transplantation can protect against development of arthritis cannot definitely be answered because in this first case series some aspects of meniscus transplantation that have not been considered which turned out to be of importance during the last 20 years. Furthermore, it has to be taken into account that all patients revealed a cartilage damage at the time of surgery and an ACL reconstruction was performed in addition. Nevertheless from biomechanical point of view it might be taken into consideration to combine the medial meniscus transplantation at least with a high tibial osteotomy. Level of evidence was (IV, case series).

Femoral shaft bowing influences the correction angle for high tibial osteotomy

BACKGROUND

The optimal femorotibial angle (FTA) after high tibial osteotomy (HTO) is still controversial. Our hypothesis was that FTA itself may not be reliable because FTA cannot represent the accurate alignment of the whole lower extremity.

METHODS

Non-weight-bearing radiographs of the lower extremities were taken in 100 Japanese subjects with medial osteoarthritic knees, and seven anatomic parameters were assessed. The correction angle by FTA was calculated so that the postoperative FTA was set at 166 degrees (14 degrees valgus). Another correction angle was calculated so that the mechanical axis passed through the lateral one-fourth of the tibial articular surface after HTO. After the correlation between two correction angles was assessed, influences of anatomic parameters on the discrepancy between two correction angles were assessed.

RESULTS

There was a high correlation between two correction angles (R2 = 0.777, P < 0.001). The mechanical axis passed through the lateral one-fourth of the tibial articular surface when the postoperative FTA was set at 166 degrees in 80% of subjects. However, discrepancy between the two correction angles was 3 degrees or larger in 20% of subjects. Femoral shaft bowing and tibial shaft bowing significantly influenced the correction angles. Even though FTA was the same, the femoral head shifted medially in cases with lateral bowing of the femoral shaft, and the correction angle by FTA should be set larger. On the other hand, the correction angle by FTA can be set smaller in knees with medial bowing of the femoral shaft. Tibial shaft bowing also influences the correction angle by FTA.

CONCLUSIONS

The correction angle by FTA for HTO should be calculated taking femoral and/or tibial shaft bowing in the frontal plane into account.

Osteotomy for the Early Varus Arthritic Knee

High tibial osteotomy is a well-established procedure for the management of medial compartment arthritis that is currently experiencing a resurgence in popularity. A number of techniques have been described, with the ultimate goal of obtaining appropriate alignment to provide pain relief and functional improvement over a long-term period. Appropriate patient selection and careful surgical technique is necessary to achieve these goals with a minimal risk of complication. Newer technology such as computer navigation promises to improve the overall accuracy of the procedure. The need for alignment correction in combination with ligament reconstruction and chondral resurfacing surgery will increase the indications for this procedure. This article discusses the techniques available for high tibial osteotomy, the results and relative advantages of each, and the appropriate surgical technique to achieve optimal results while minimizing complications.

Influence of high tibial osteotomy on bone marrow edema in the knee

To determine the influence of high tibial osteotomy on subchondral bone marrow edema in medial osteoarthritis of the varus knee, full leg-length radiographs and magnetic resonance imaging were performed in 20 patients (20 knees) before surgery, 1 year postoperatively, and at a mean of 7 years postoperatively. The extent of bone marrow edema in the medial compartment was quantified with magnetic resonance imaging in two planes using the formula for a prolate ellipsoid as follows: length x width x depth x pi/6. We used the Japanese Orthopaedic Association knee score for clinical evaluation. At the last followup, all knees with valgus alignment (10/10) showed reduced edema. In contrast, bone marrow edema increased or remained unchanged in four of 10 knees with neutral or varus alignment. The percentage of satisfactory results was 100% (10/10) in valgus knees and only 30% (3/10) in neutral or varus knees. Extent of bone marrow edema at the followup correlated with the mechanical axis and knee score. Because of the prognostic value of bone marrow abnormalities in the medial compartment observed on magnetic resonance imaging, early lateral closing wedge osteotomy should be considered in patients with varus malalignment and bone marrow edema even in mild cases of medial osteoarthritis.

Influence of lower-limb torsion on long-term outcomes of tibial valgus osteotomy for medial compartment knee osteoarthritis

BACKGROUND

The results of tibial osteotomy used to treat osteoarthritis of the medial compartment of the knee deteriorate over time even when the initial correction is optimal. Studies have shown that tibial and femoral torsion and the femorotibial index (tibial torsion minus femoral torsion) contribute, together with coronal malalignment, to the development of single-compartment knee osteoarthritis. The objective of our study was to evaluate the impact of femoral and tibial torsion and of coronal realignment on the long-term clinical and radiographic outcomes of valgus tibial osteotomy.

METHODS

A function score was calculated for sixty-eight patients at a mean of thirteen years after the osteotomy. Anteroposterior single-leg-stance radiographs were used to evaluate loss of the femorotibial joint space. Goniometry was used to measure coronal malalignment preoperatively, at one year, and at the time of the last follow-up, and postoperative computed tomography was performed to measure femoral anteversion and tibial torsion and to calculate the femorotibial index. We looked for associations linking body mass index, initial loss of joint space, coronal malalignment, femoral and tibial torsion, the femorotibial index, and functional outcomes.

RESULTS

Worse outcomes were associated with changes in coronal alignment (>/=2 degrees ) over time, which were associated with deterioration of the femorotibial space. Femoral anteversion was significantly greater in patients in whom valgus increased over time than in those in whom valgus decreased over time. Stability of coronal alignment seemed to be dependent on a linear relationship between the femorotibial index and the degree of postoperative realignment. A body mass index of >25 kg/m(2) was associated with a long-term loss of coronal realignment. Preoperative loss of the medial femorotibial joint space, coronal alignment at one year, and age were not associated with secondary malalignment or functional outcomes.

CONCLUSIONS

Long-term success of a valgus tibial osteotomy is related to the stability over time of the postoperative coronal realignment. Therefore, the results of our study suggest that modifying the realignment according to the extent of femoral anteversion may improve long-term outcomes.

Three-dimensional knee motion before and after high tibial osteotomy for medial knee osteoarthritis

BACKGROUND

High tibial osteotomy (HTO) is an established surgical option for treating medial knee osteoarthritis. HTO moves the mechanical load on the knee joint from the medial compartment to the lateral compartment by changing the leg alignment, but the effects of the operation remain unclear. The purpose of this study was to evaluate the change in three-dimensional knee motion before and after HTO, focusing on lateral thrust and screw home movement, and to investigate the relationship between the change in knee motion and the clinical results.

METHODS

A series of 19 patients with medial knee osteoarthritis who had undergone HTO were evaluated. We performed a clinical assessment, radiological evaluation, and motion analysis at 2.4 years postoperatively. The clinical assessment was performed using the Japanese Orthopaedic Association knee score.

RESULTS

The score was significantly improved in all patients after operation. Motion analysis revealed that lateral thrust, which was observed in 18 of the 20 knees before operation, was reduced to 7 knees after operation. Regarding active terminal extension of the knee, three patterns of rotational movement were observed before operation: screw home movement (external rotation), reverse screw home movement (internal rotation), and no rotation. By contrast, after operation, only reverse screw home movement and no rotation were observed; the screw home movement disappeared in all patients. In the knees with reverse screw home movement after operation, the preoperative score was significantly lower than those in the knees with no rotation after operation.

CONCLUSIONS

Kinetically, HTO was useful for suppressing lateral thrust in medial knee osteoarthritis, although the rotational movement of the knee joint was unchanged.

Minimal-invasive navigiert implantierte unikondyläre Knieendoprothese

METHODS

From January 2003 to July 2005 a total of 50 St Georg medial knee monosleds with metal-backed tibial components in stably seated form and Uniglide prostheses (Alphanorm/Corin) with mobile bearing onlays were implanted in minimally invasive operations. Postoperatively the alignment-especially of the tibial components-was investigated, to check whether we had achieved the dorsal slope we had been aiming at, i.e. 5-7 degrees , in the region of these knee replacements.

RESULTS

Before surgery there were initial malalignments of up to 10 degrees varus and 3 degrees valgus. All leg axes were restored to between -3 degrees and +3 degrees . The desired dorsal slope of 5-7 degrees for the knee monosleds relative to the tibial component was realized, the average slope being 5.3 degrees . The a-p alignment of the tibial component and of the femoral component was correct.

CONCLUSIONS

Use of the navigation system leads to more accurate and reproducible results in terms of tibial dorsal slope, which is extremely important when these monosleds are used. Overcorrection of the leg axis is generally avoided. The use of too-high medial onlays is also reliably avoided by the navigation system's monitoring of the level of the cut.

High tibial osteotomy that does not cause recurrence of varus deformity for medial gonarthrosis

It is widely accepted that high tibial osteotomy (HTO) is an effective surgical treatment for medial gonarthrosis. However, long-term follow-up studies have revealed that the clinical results deteriorate over time and varus deformity often recurs. We performed barrel-vault osteotomy in HTO with a correction angle that did not cause arthritic progression in the medial compartment of the knee or recurrence of varus deformity. Thirty patients (44 knees) were followed clinically and radiographically for a minimum of 10 years (average, 11.4 years). We aimed for an average postoperative femorotibial angle (FTA) of 165.3 degrees (range, 162-169 degrees ) according to our method using a correction angle chosen on the basis of the so-called Mikulicz's mechanical axis. The clinical results were good in 30 (68.2%) knees, fair in 7 (15.9%) and poor in 7 (15.9%). Arthritic progression in the medial compartment was only found in 1 (2.3%) knee, while in the lateral compartment it was found in 17 (38.6%) knees. Of the knees with arthritic progression in the lateral compartment, six (35.3%) were classified as poor. The average postoperative FTAs were 164.3 degrees at 1 year, 164.0 degrees at 5 years and 163.5 degrees at 10 years after the operation, indicating that the knees tended to become slightly valgus over time. The clinical results were not poor after slightly overcorrected osteotomy was performed. Since overcorrection tended to occur, when the preoperative lateral tibial thrust was severe, HTO is not a good indication for such cases.

Deterioration of long-term results following high tibial osteotomy in patients under 60 years of age

We have investigated, in a prospective study, the outcome of a valgus osteotomy of the tibia in patients less than 60 years of age with arthrosis of the medial compartment and a varus angle of no more than 177.7 degrees . Included in the study were 44 high tibial osteotomies (HTO) performed in 42 patients from 1981 until 1996. There were 35 females (2 bilateral) and 7 males, with an average age of 51 years (range: 30-60 years). Only patients in the first three grades, according to Ahlback's classification, were included. During a mean follow-up period of 10 years (range: 5-17 years), all but 2 patients experienced pain relief. The average loss of postoperative correction at 10 years was 2.4 degrees . The average postoperative Hospital for Special Surgery Knee Rating System score (HSSK) for patients with excellent or good results was 83.5 points. Survivorship analysis showed a success rate of 80% and 66% at 10 and 15 years respectively, and over 52.8% at 17 years of follow-up. HTO results in redistribution of the main stresses towards normal levels, although normal values are never attained. This is probably the reason why patients experienced good results only in the medium term.

The high tibial osteotomy, open versus closed wedge, a comparison of methods in 108 patients

INTRODUCTION

One hundred and eight patients with varus gonarthrosis were treated with high tibial osteotomy (HTO) in 2001. Fifty one patients received an open wedge osteotomy by using the 'Puddu' plate and 57 patients received a Coventry-type closing wedge osteotomy. For both groups the follow-up examination period was 22.5 months (253-1009 days).

MATERIAL AND METHODS

To evaluate the study, radiological and subjective criteria as well as the Lysholm and the Tegner Activity Score were used. Altogether 84 % of the patients were included in the follow-up examination study.

RESULTS

In both groups a significant improvement of both scores were achieved. Both methods obtained safe and reproducible results for the correction considering the different operation techniques. There were no differences in outcome between the two methods. Satisfactory results were also achieved for early arthrosis of the femoropatellar and the lateral compartment.

CONCLUSION

Open and closed wedge HTOs obtain significant improvement in patients with medial osteoarthritis of the knee. Using the right technique is very important for good results. For stabilization of the medial ligament we recommend the open wedge osteotomy. The patient should be informed about the routine removal of the metal plate.

Biomechanical stability of high tibial opening wedge osteotomy: internal fixation versus external fixation

PURPOSE

The goal of our study was to evaluate stability of internal fixation with a plate compared to external fixation in an opening wedge high tibial osteotomy model. Significance. To our knowledge, this is the only study to compare internal plate to external fixation in an opening wedge osteotomy model. The design of this cadaver study limits its direct application to clinical practice.

MATERIAL AND METHOD

In each of the six pairs of fresh-frozen human cadaver knees one specimen was randomly assigned to internal plate fixation while the other was stabilized with an external fixation. The osteosynthesis plate incorporated a 12.5mm block that distracted the medial tibial cortices. Each knee was loaded on a mechanical testing machine to 700 N for 10,000 cycles to simulate immediate full weight bearing in a walking individual.

SUMMARY OF RESULTS

The internal plate osteosynthesis provided significantly greater stiffness and smaller loss of correction (1.60mm) than the external fixation (3.22 mm) under cyclic loading condition (P<0.05). For static loading, the mean value of stiffness resulting in failure for the internal plate and external fixation, were respectively, 938 N/mm and 459 N/mm. Load to failure also showed two times greater stiffness in the plate osteosynthesis group. No hardware failure was observed in either construct.

DISCUSSION AND CONCLUSION

Plate fixation was superior to external fixation in maintaining correction. However, progressive adjustment of the distraction with the external fixator allows precise "fine-tuning" during the healing process that is not possible with internal fixation.

Tricalcium phosphate granules or rigid wedge preforms in open wedge high tibial osteotomy: a radiological study with a new evaluation system

The capacity of two forms of porous beta-tricalcium phosphate bone substitutes (TCP) to promote bone healing in open wedge high tibial osteotomy (OWHTO) was studied. We reviewed the X-rays of 27 osteotomies, with either TCP wedges or TCP granules as filling material, to compare the bone healing rates and bone remodelling, at specific postoperative intervals. A new radiologic rating system for OWHTO was created and tested for clinical applicability. All osteotomies healed uneventfully and complete resorption of TCP was demonstrated at 1 year postoperative in 85% (n = 23) of the procedures. In 44% (n = 10) of these 23 procedures, the osteotomy site was no longer visible. No difference in bone healing rate and bone remodelling was found when comparing the use of granules to a wedge, and no adverse effects of TCP were observed. The good inter- (k = 0.7) and intraobserver (k = 0.6) reliability of the new radiologic rating system enables clinical use. Good bone healing was found in OWHTO with both wedges and granules of TCP.

Unicompartmental knee arthroplasty in patients sixty years of age or younger

BACKGROUND

Unicompartmental knee arthroplasty has been used to treat elderly, low-demand patients, but the literature is sparse regarding the use of this procedure for younger, active patients. The purpose of the present retrospective study was to evaluate the results of unicompartmental knee arthroplasty in younger, more active patients.

METHODS

Forty-one patients underwent forty-six consecutive unicompartmental knee arthroplasties with use of the Miller-Galante system between 1988 and 1996. All of the patients were sixty years of age or younger and all were physically active. The Hospital for Special Surgery knee score and the University of California at Los Angeles activity assessment were used to rate the function and to determine the activity level of each patient, respectively. Serial radiographs were used to evaluate the status of prosthetic fixation, femorotibial alignment, and the progression of arthrosis in the unreplaced compartment. Long-term survivorship was calculated with use of Kaplan-Meier analysis.

RESULTS

The mean duration of follow-up was eleven years. Of the forty-five knees that were available for follow-up, three had been revised. The Hospital for Special Surgery score was excellent for thirty-nine (93%) of the remaining forty-two knees and good for three. The University of California at Los Angeles activity assessment score was 6.6 +/- 1.4 for the knees in which the original prosthesis had been retained and 7.3 +/- 1.5 for those in which it had been revised. Two asymptomatic patients had revision of a modular tibial component because of substantial radiographic evidence of polyethylene wear; one of these patients had exchange of the polyethylene insert and the tibial tray, and the other had exchange of the polyethylene insert only. A third patient underwent revision total knee arthroplasty because of continuing knee pain and a progressive tibial radiolucent line that was >2 mm in width. The average postoperative femorotibial alignment was 5 degrees of valgus. Nine knees had progression of arthritis in the unresurfaced compartment; none of these knees were revised, and none of the patients had deterioration in the Hospital for Special Surgery score. Kaplan-Meier analysis demonstrated an eleven-year survivorship of 92%.

CONCLUSIONS

At an average duration of follow-up of eleven years, unicompartmental knee arthroplasty was associated with pain relief and excellent function in a cohort of patients who had been sixty years of age or younger and active at the time of surgery.