Can young and active patients participate in sports after osteochondral autologous transfer combined with valgus high tibial osteotomy?

Clinical Outcomes and Long-term Survivorship After Osteochondral Autologous Transfer Combined With Valgus High Tibial Osteotomy: An Analysis After 19 Years With 56 Patients

BACKGROUND

Osteochondral defects of the medial femoral condyle combined with varus malalignment in young and active patients are a debilitating condition, which can result in early osteoarthritis. Osteochondral autologous transfer (OAT) combined with valgus high tibial osteotomy (HTO) might therefore be a comprehensive solution to maintain long-term knee function.

PURPOSE/HYPOTHESIS

The purpose of this study was to report clinical results and survivorship after combined OAT and valgus HTO for symptomatic osteochondral defects of the medial femoral condyle in the setting of varus malalignment at a long-term follow-up. It was hypothesized that undergoing combined OAT and valgus HTO would produce favorable clinical results along with a low rate of conversion to arthroplasty.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

All patients treated between 1998 and 2008 with combined valgus HTO and OAT for deep osteochondral defects of the medial femoral condyle and concomitant varus malalignment >2° without meniscal repair/transplantation, osteoarthritis, or ligamentous instability/reconstruction were included. The survival rates of this combined procedure were evaluated. Failure was defined as conversion to knee joint arthroplasty during the follow-up period. Patient-reported outcomes were collected pre- and postoperatively, including the Lysholm score, visual analog scale score, Knee injury and Osteoarthritis Outcome Score (KOOS), Tegner Activity Scale score, and subjective level of satisfaction (scale 0-10).

RESULTS

Of 74 patients who were included for 10-year follow-up, 3 had died. A total of 15 patients were lost to follow-up, so 56 patients could be reevaluated, for a follow-up rate of nearly 80%. The mean age at surgery was 38.8 ± 9.9 years (range, 19.9-62.4 years), and the mean follow-up time was 18.9 ± 3.0 years (median, 18.8 years; range, 14.1-24.8 years). The survival rates were 87% at 10 years, 86% at 15 years, and 77% at 19 years after surgery. At final follow-up, the Lysholm score showed a mean increase of 39 points (95% CI, 25.4-50.0 points; P < .001) from 40 points to 79 points, representing a significant improvement. Overall, 96% of patients surpassed the minimal clinically important difference (MCID) for the Lysholm score. The visual analog scale score decreased by a mean of 4.8 points (range, 5-10 points) from 7.5 points to 2.7 points (P < .001), and 80% of patients surpassed the MCID. The mean Tegner Activity Scale score was 4.5 ± 1.6, and the mean KOOS subscale scores at final follow-up were as follows: Pain: 81 ± 21 (range, 19-100), Symptoms: 80 ± 22 (range, 21-100), Activities of Daily Living: 85 ± 21 (range, 18-100), Sports: 68 ± 32 (range, 0-100), and Quality of Life: 67 ± 28 (range, 0-100). Overall, 78% of the patients were satisfied with the results of the operation.

CONCLUSION

The combination of OAT and valgus HTO presents a viable treatment option for patients affected by osteochondral defects of the medial femoral condyle and concurrent varus malalignment. A sustained and substantial improvement in clinical outcomes, significantly reduced pain severity, and a high rate of long-term survivorship can be anticipated in the long-term follow-up.

Evaluating Return to Sports After Surgical Treatment of Unstable Osteochondritis Dissecans of the Knee: A Systematic Review

Background

Although the incidence of osteochondritis dissecans (OCD) of the knee may be low, an overview and comparison of sports-related outcomes with current surgical management techniques are needed.

Purpose

To summarize the available evidence regarding outcomes for different surgical treatment options for unstable OCD of the knee in both skeletally mature and immature patients by calculating the return to sports (RTS) rate, the mean RTS time, and other sports-related postoperative outcome measures.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic review of studies on RTS after surgical correction of unstable OCD within the knee was conducted utilizing PubMed, Embase, and the Cochrane databases. Included were studies discussing the treatment of unstable OCD with minimum 1-year follow-up outcomes. Multivariate analysis was used to compare studies grouped together based on RTS and skeletal maturity.

Results

Of 2229 articles, 6 studies (197 patients; 198 knees) met the inclusion criteria and were included in our analysis. The percentage of patients who returned to the previous level of sport ranged from 52% to 100%; those returning to any level of sport ranged from 87% to 100%. Clinical outcomes did not differ between patients with open versus closed physes. Osteochondral Autograft Transfer System (OATS) procedures had a 100% RTS rate across several studies with skeletally mature and mixed cohorts, and microfracture had the lowest overall RTS rate (52%). For skeletally immature patients, all examined studies that utilized either open or arthroscopic reduction and internal fixation, 77% and 78%, respectively, had acceptable RTS rates. Arthroscopic fixation had a higher rate of revision surgery in both skeletally mature and immature patients.

Conclusion

Our analysis indicated that the treatment of unstable OCD lesions using the OATS technique demonstrated high RTS rates across several studies, while microfracture alone exhibited the lowest RTS rate. Both arthroscopic and open internal fixation utilizing bioabsorbable screws yielded satisfactory RTS rates for juvenile patients with OCD.

Better clinical outcomes and return to sport rates with additional medial meniscus root tear repair in high tibial osteotomy for medial compartmental knee osteoarthritis

PURPOSE

This retrospective study aimed to investigate whether the repair of medial meniscus posterior root tears (MMPRTs) is effective for improving clinical outcomes and return to sports rates in young patients (50 years old or younger) with medial compartment knee osteoarthritis (KOA) and MMPRTs.

METHODS

Between 2016 and 2019, 153 patients with KOA and MMPRTs who underwent open-wedge high tibial osteotomy (OWHTO) were retrospectively included. The patients were divided into OWHTO combined with MMPRT repair (n = 73) and isolated OWHTO (n = 80) groups. Lysholm scores, Hospital for Special Surgery (HHS) scores, Tegner scores, flexion contracture, range of knee flexion, return to sports rates and postoperative complications were compared. Radiological outcomes, including hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA), joint line convergence angle (JLCA) and Kellgren-Lawrence (K-L) grade, were compared between the two groups.

RESULTS

After a mean follow-up of 30.1 ± 3.0 months, the OWHTO + Repair group observed better clinical outcomes compared with the OWHTO group (Lysholm score: 86.7 ± 7.4 vs. 81.6 ± 6.9, p = 0.023. HHS score: 85.4 ± 8.20 vs. 80.5 ± 7.1, p = 0.039). The OWHTO + Repair group had higher Tegner scores and return to sports rates than the OWHTO group (Tegner score: 6 vs. 5, p = 0.020; return to sports rates: 38% vs. 15%, p = 0.001). No fracture or major complications occurred. Radiological outcomes showed no significant differences between the two groups (HKA: 181.1 ± 2.7 vs. 180.1 ± 1.5 n.s; MPTA: 90.1 ± 1.8 vs. 89.2 ± 1.4, n.s; JLCA:1.9 ± 0.7 vs. 2.1 ± 0.7, n.s).

CONCLUSIONS

Additional MMPRT repair during OWHTO was associated with better clinical outcomes and higher rates of return to sports in young patients with medial compartment KOA and MMPRTs.

LEVEL OF EVIDENCE

Level III.

High tibial osteotomy combined with cartilage restoration: A systematic review of clinical outcomes and prognostic factors

Background

Focal chondral defects are often treated with cartilage restoration procedures. Malalignment often accompanies chondral defects. High tibial osteotomy (HTO), classically utilized to treat uni-compartmental knee osteoarthritis, corrects malalignment. HTO combined with cartilage restoration procedures can treat uni-compartmental osteoarthritis and focal chondral defects.

Purpose

To assess outcomes of combined HTO and cartilage restoration procedures and review prognostic factors that may assist in preoperative planning and patient counseling.

Study design

Systematic Review of published literature.

Methods

A systematic review of PubMed and Scopus was performed following PRISMA guidelines. Thirty-four papers were included in qualitative considerations.

Results

Thirty-four papers that reported the combined outcome of HTO and cartilage repair were included. Twenty of the 34 included papers reported prognostic factors that affected the success or failure of combined HTO and cartilage repair surgery for focal articular defect and uni-compartmental knee osteoarthritis. Cartilage repair techniques that were combined with HTO and included in this review are bone marrow stimulation, allograft transplantation, osteochondral autograft transplantation, autologous chondrocyte implantation, and mesenchymal stem cell implantation.

Conclusions

HTO with adjunctive cartilage repair procedures improve clinical outcome scores and restore alignment in patients with medial compartment osteoarthritis and isolated focal chondral defects. HTO with adjunctive cartilage procedures produces optimal results in younger, non-obese patients with focal chondral defects and varus malalignment, without significant lateral compartment and patellofemoral involvement.

Muti-factor analysis of sport activity level after high tibial osteotomy

BACKGROUND

Although many studies have shown that high tibial osteotomy is appropriate for active patients, there are limited multifactorial studies on patients' sport activity level after HTO in general population.

METHODS

158 patients who underwent HTO for knee osteoarthritis between January 2016 and December 2019 are included, with a 36-month follow-up. Information was collected from X-rays and questionnaire. The independent variables were age, sex, breadwinner (provide more than 50% income), sport activity level when the knee was pain-free before and after surgery, concomitant meniscal treatment history, Lysholm knee score, desire level for returning to sports. The 158 cases are divided into three groups according to their sports participation before and after operation, Chi-square tests and ANOVA analysis were adopted to identify the effect of these variables on sport activity level after HTO, and factors with statistical differences and clinical relevancies, or provided by previous research were assessed with the ordinal logistic regression analysis.

RESULTS

According to sport activity level analysis, 28(17.7%) patients were categorized into the sport level-reduced group, 97(61.4%) patients into the sport level-unchanged group, and 33(20.9%) patients into the sport level-improved group. Upon ordinal logistic regression analysis, postoperative MA%, age, BMI, and preoperative Lysholm knee score were statistically significant.

CONCLUSIONS

Higher postoperative MA%, younger age, lower BMI, and lower Lysholm score are associate with improvement on activity level after HTO. This finding provides valuable references in operation option and rehabilitation planning.

Small-Molecule Loaded Biomimetic Biphasic Scaffold for Osteochondral Regeneration: An In Vitro and In Vivo Study

Osteoarthritis is a prevalent musculoskeletal disorder in the elderly, which leads to high rates of morbidity. Mesenchymal stem cells (MSCs) are a promising approach to promote tissue regeneration in the absence of effective long-term treatments. Small molecules are relatively inexpensive and can selectively alter stem cell behavior during their differentiation, making them an attractive option for clinical applications. In this study, we developed an extracellular matrix (ECM)-based biphasic scaffold (BPS) loaded with two small-molecule drugs, kartogenin (KGN) and metformin (MET). This cell-free biomimetic biphasic scaffold consists of a bone (gelatin/hydroxyapatite scaffold embedded with metformin [GHSM]) and cartilage (nano-gelatin fiber embedded with kartogenin [NGFK]) layer designed to stimulate osteochondral regeneration. Extracellular matrix (ECM)-based biomimetic scaffolds can promote native cell recruitment, infiltration, and differentiation even in the absence of additional growth factors. The biphasic scaffold (BPS) showed excellent biocompatibility in vitro, with mesenchymal stem cells (MSCs) adhering, proliferating, and differentiated on the biomimetic biphasic scaffolds (GHSM and NGFK layers). The biphasic scaffolds upregulated both osteogenic and chondrogenic gene expression, sulfated glycosaminoglycan (sGAG), osteo- and chondrogenic biomarker, and relative mRNA gene expression. In an in vivo rat model, histo-morphological staining showed effective regeneration of osteochondral defects. This novel BPS has the potential to enhance both subchondral bone repair and cartilage regeneration, demonstrating excellent effects on cell homing and the recruitment of endogenous stem cells.

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

Background:

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

Purpose:

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

Study Design:

Case-control study; Level of evidence, 3.

Methods:

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

Results:

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

Conclusion:

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

Improved Accuracy of Coronal Alignment Can Be Attained Using 3D-Printed Patient-Specific Instrumentation for Knee Osteotomies: A Systematic Review of Level III and IV Studies

PURPOSE

To evaluate the accuracy and precision of postoperative coronal plane alignment using 3D-printed patient-specific instrumentation (PSI) in the setting of proximal tibial or distal femoral osteotomies.

METHODS

A systematic review evaluating the accuracy of 3D-printed PSI for coronal plane alignment correcting knee osteotomies was performed. The primary outcomes were accuracy of coronal plane limb alignment correction and number of correction outliers. Secondary variables were duration of surgery, number of intraoperative fluoroscopic images, complications, cost, and clinical outcomes (as applicable).

RESULTS

Ninety-three studies were identified, and 14 were included in the final analysis. Overall, mean postoperative deviation from target correction ranged from 0.3° to 1° for all studies using hip-knee angle measurements and 2.3% to 4.9% for all studies using weight-bearing line measurements. The incidence of correction outliers was assessed in 8 total studies and ranged from 0 to 25% (total n = 10 knees) of patients corrected with 3D-printed PSI. Osteotomies performed with 3D-printed cutting guides or wedges demonstrated significantly shorter operative times (P < .05) and fewer intraoperative fluoroscopic images (P < .05) than control groups in four case control studies.

CONCLUSION

Patients undergoing distal femoral osteotomy or proximal tibial osteotomy procedures with 3D-printed patient-specific cutting guides and wedges had highly accurate coronal plane alignment with a low rate of outliers. Patients treated with 3D printed PSI also demonstrated significantly shorter operative times and decreased intraoperative fluoroscopy when compared to conventional techniques.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III-IV studies.

Arthroscopic Osteochondral Autograft Transfer System Procedure of the Lateral Femoral Condyle with Donor-Site Backfill Using Osteochondral Allograft Plug

The osteochondral autograft transfer system (OATS) procedure is at the forefront of cartilage restoration surgeries of the knee, offering superior return to sport rates and long-term functionality. This technique reports an arthroscopic OATS procedure of the lateral femoral condyle with donor-site backfill using an osteochondral allograft plug. Potential complications from unfilled donor site sockets are eliminated through donor site backfill with an allograft plug.

[Relevance of meniscus loss for the progression of osteoarthritis and treatment options for early arthritis]

Meniscal tears are still one of the most frequent lesions in the knee joint. The relevance of meniscus loss for the development of osteoarthritis is undisputed. Meniscus repair, replacement and transplantation play an important role in the treatment of early arthritis, especially when they are a part of a master plan including alignment correction, stabilization and cartilage surgery, if needed. Scientific data show evidence concerning the protection of osteoarthritis, even though a lack of studies including comparison groups has to be admitted.

Return to sports rate after opening wedge high tibial osteotomy in athletes

PURPOSE

We hypothesized that patient treated with OWHTO who participate in high-impact sports would attain satisfactory outcome. The purpose of this study was to examine the clinical and radiological outcomes in a consecutive series of opening-wedge high tibial osteotomy (OWHTO) in highly active patients.

METHODS

Seventy-seven consecutive patients who underwent OWHTO with varus osteoarthritic knees were included in the study. The mean age of the study population was 56.1 years. All patients were followed for a minimum of 2 years. Clinical and radiological evaluations were performed at 12 and 24 months after surgery. The clinical results were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC) Subjective Score. In regards to radiological assessment, the following parameters were measured in full-length weightbearing radiographs both pre- and postoperatively; mechanical tibiofemoral angle (mTFA), mechanical lateral distal femoral angle (mLDFA), and weight bearing line (WBL) ratio.

RESULTS

Fifty-eight patients (75.3%) returned to the same high-impact sports activities as before surgery, with a mean time to return of 8.7 ± 2.7 months (6-14 months). In the clinical assessments, the IKDC subjective score and KOOS both improved from the mean preoperative scores of 38.4 and 217.4 points to the mean postoperative scores of 74.5 and 421.6 points, respectively. The mean pre-symptomatic Tegner activity scale was 5.3 ± 0.6 and significantly decreased to 4.8 ± 1.2 at 2 years postoperative (p < 0.05). In the radiological evaluation, the postoperative mTFA, mMPTA, and WBL ratio values averaged 1.3° ± 2.2° valgus, 90.7° ± 2.9°, and 51.6% ± 8.4°, respectively, at 24 months after surgery.

CONCLUSIONS

Clinical outcomes based on postoperative patient-reported outcome measures and rate of return to high-impact sports activities were favorable after OWHTO in patients with knee OA who desired to continue sporting activities with the Tegner activity score of  ≥ 5 points.

LEVEL OF EVIDENCE

Retrospective case series, IV.

Isolated high tibial osteotomy is appropriate in less than two-thirds of varus knees if excessive overcorrection of the medial proximal tibial angle should be avoided

PURPOSE

To perform a detailed deformity analysis of patients with varus alignment and to define the ideal osteotomy level (tibial vs. femoral vs. double level) to avoid an oblique joint line.

METHODS

A total of 303 digital full-leg standing radiographs of patients aged 18-60 years and varus alignment [mechanical tibiofemoral varus angle (mFTA) ≥ 3°] were included. All legs were analyzed regarding mFTA, mechanical medial proximal tibia angle (mMPTA), mechanical lateral distal femur angle (mLDFA), and joint line convergence angle. Based on mFTA, varus alignment was categorized as "mild" (3°-5°), "moderate" (6°-8°), or "severe" (≥ 9°). Deformity location was determined according to the malalignment test described by Paley. Two osteotomy simulations were performed with different upper limits for mMPTA: anatomic correction (mMPTA ≤ 90°, mLDFA ≥ 85°) and overcorrection (mMPTA ≤ 95°, mLDFA ≥ 85°). If a single osteotomy exceeded these limits at the intended mFTA of 2° valgus, a double-level osteotomy was simulated. If even a double-level osteotomy resulted in deviations from the defined limits, the leg was categorized as "uncorrectable".

RESULTS

Mean mFTA was 6° ± 11° of varus (range 3°-15°). A tibial deformity was observed in 28%, a femoral deformity in 23%, a combined tibial and femoral deformity in 4%, and no bony deformity in 45%. The prevalence of a tibial deformity did not differ between varus severity groups, whereas a femoral and bifocal deformity was significantly more prevalent in knees with more distinct varus (p < 0.001). Osteotomy simulation revealed that isolated high tibial osteotomy (HTO) was appropriate in only 12% for anatomic correction, whereas a double-level osteotomy was necessary in 63%. If overcorrection of mMPTA was tolerated, the number of HTOs significantly increased to 57% (p < 0.001), whereas the number of double-level osteotomies significantly decreased to 33% (p < 0.001). Isolated DFO was considered ideal in 8% for both simulations. Significantly more knees were considered "uncorrectable" by simulating anatomic correction (18 vs. 2%; p < 0.001). A double-level osteotomy was significantly more often necessary in knees with "severe" varus (p < 0.001).

CONCLUSION

Less than one-third of patients (28%) with mechanical varus ≥ 3° have a tibial deformity. If anatomic correction (mMPTA ≤ 90°) is intended, only 12% of patients can be corrected via isolated HTO, whereas 63% of patients require a double-level osteotomy. If slight overcorrection is accepted (mMPTA ≤ 95°), 57% of patients can be corrected via isolated HTO, whereas 33% of patients would still require a double-level osteotomy.

LEVEL OF EVIDENCE

III, cross-sectional study.

Sporting participation following the operative management of chondral defects of the knee at mid-term follow up: a systematic review and meta-analysis

PURPOSE

The purpose of this study was to perform a systematic review of the reparticipation in sport at mid-term follow up in athletes who underwent biologic treatment of chondral defects in the knee and compare the rates amongst different biologic procedures.

METHODS

A search of PubMed/Medline and Embase was performed in May 2020 in keeping with Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. The criteria for inclusion were observational, published research articles studying the outcomes and rates of participation in sport following biologic treatments of the knee with a minimum mean/median follow up of 5 years. Interventions included microfracture, osteochondral autograft transfer (OAT), autologous chondrocyte implantation (ACI), matrix-induced autologous chondrocyte implantation (MACI), osteochondral allograft, or platelet rich plasma (PRP) and peripheral blood stem cells (PBSC). A random effects model of head-to-head evidence was used to determine rates of sporting participation following each intervention.

RESULTS

There were twenty-nine studies which met the inclusion criteria with a total of 1276 patients (67% male, 33% female). The mean age was 32.8 years (13-69, SD 5.7) and the mean follow up was 89 months (SD 42.4). The number of studies reporting OAT was 8 (27.6%), ACI was 6 (20.7%), MACI was 7 (24.1%), microfracture was 5 (17.2%), osteochondral allograft was 4 (13.8%), and one study (3.4%) reported on PRP and PBSC. The overall return to any level of sport was 80%, with 58.6% returning to preinjury levels. PRP and PBSC (100%) and OAT (84.4%) had the highest rates of sporting participation, followed by allograft (83.9%) and ACI (80.7%). The lowest rates of participation were seen following MACI (74%) and microfracture (64.2%).

CONCLUSIONS

High rates of re-participation in sport are sustained for at least 5 years following biologic intervention for chondral injuries in the knee. Where possible, OAT should be considered as the treatment of choice when prolonged participation in sport is a priority for patients. However, MACI may achieve the highest probability of returning to the same pre-injury sporting level.

LEVEL OF EVIDENCE

IV.

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN

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

METHODS

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

RESULTS

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

CONCLUSION

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

Osteochondral Regeneration Using Adipose Tissue-Derived Mesenchymal Stem Cells

Osteoarthritis (OA) is a major joint disease that promotes locomotor deficiency during the middle- to old-age, with the associated disability potentially decreasing quality of life. Recently, surgical strategies to reconstruct both articular cartilage and subchondral bone for OA have been diligently investigated for restoring joint structure and function. Adipose tissue-derived mesenchymal stem cells (AT-MSCs), which maintain pluripotency and self-proliferation ability, have recently received attention as a useful tool to regenerate osteocartilage for OA. In this review, several studies were described related to AT-MSC spheroids, with scaffold and scaffold-free three-dimensional (3D) constructs produced using “mold” or “Kenzan” methods for osteochondral regeneration. First, several examples of articular cartilage regeneration using AT-MSCs were introduced. Second, studies of osteochondral regeneration (not only cartilage but also subchondral bone) using AT-MSCs were described. Third, examples were presented wherein spheroids were produced using AT-MSCs for cartilage regeneration. Fourth, osteochondral regeneration following autologous implantation of AT-MSC scaffold-free 3D constructs, fabricated using the “mold” or “Kenzan” method, was considered. Finally, prospects of osteochondral regeneration by scaffold-free 3D constructs using AT-MSC spheroids were discussed.

Osteochondral Autograft Transfer Procedure: Arthroscopic Technique and Technical Pearls

The Osteochondral Autograft Transfer System (OATS; Arthrex, Naples, FL) is an excellent option for the treatment of articular cartilage lesions within the knee. Current literature suggests that at early-term to midterm follow-up, patients experience improved function, alleviation of pain, and good satisfaction with acceptable complication rates. Although long-term data are lacking, studies in athletes have shown that the OATS can provide an adequate rate of return to sports. The OATS procedure has traditionally been considered an open procedure. However, with the advancement of arthroscopic techniques, the procedure can now be completed arthroscopically. We discuss this modern operation.

A Scaffold-Free Allogeneic Construct From Adipose-Derived Stem Cells Regenerates an Osteochondral Defect in a Rabbit Model

PURPOSE

To determine whether an osteochondral defect could be healed histologically by implanting allogeneic 3-dimensionally formed adipose-derived stem cells (ADSCs) in a rabbit model.

METHODS

Thirty Japanese white rabbits (aged 15-17 weeks) were assigned to 1 of 2 groups. An osteochondral defect (diameter, 4.8 mm; depth, 3 mm) was created in the trochlear groove of the knee using a drill. The defects were left empty in the control group and were filled with cylindrical plugs of allogeneic ADSCs extracted from adipose tissue in the experimental group. Macroscopic scoring, histologic scoring, and immunohistologic stainability of type II collagen were evaluated at 4, 8, and 12 weeks postoperatively.

RESULTS

The macroscopic scores of the healing tissue in the experimental group were significantly greater than those in the control group at 12 weeks (P = .031). Histologically, safranin O staining was noted at 4 weeks and increased gradually over time in the experimental group. The modified International Cartilage Repair Society histologic score in the experimental group was significantly higher than that in the controls at 8 and 12 weeks (14 vs 9 at 8 weeks [P = .008], 18 vs 10 at 12 weeks [P = .007]). The implanted tissue was positive for type II collagen, and stainability increased gradually over time.

CONCLUSIONS

The 3-dimensional scaffold-free allogeneic ADSCs implanted into the osteochondral defect survived, adhered to the defect, increased the stainability of type II collagen gradually over time, and promoted histologic healing in a rabbit model.

CLINICAL RELEVANCE

ADSC implantation designed to promote osteochondral healing may play an important role in osteochondral healing.

Customized post-operative alignment improves clinical outcome following medial open-wedge osteotomy

PURPOSE

High tibial osteotomy (HTO) has gained more importance in the treatment of cartilage damage or osteoarthritis of the medial compartment with concurrent varus deformity. Concerning the extent of axis correction, various different views exist. The aim of this study was to evaluate the effect of the size of axis correction on functional outcome in patients undergoing a valgus HTO.

METHODS

From 2005 to 2013, 156 patients with an underlying varus deformity and cartilage damages or unicompartimental osteoarthritis of the medial compartment were treated by HTO. Retrospectively patients were allocated into three different groups according to the degree of axis correction. For this purpose, three adjacent areas, respectively, comprising 5% of the tibial plateau were defined. Limits of those areas were set as follows: with the medial border representing the 0% point and the lateral border representing the 100 point, the three areas were separated according to their limiting intersection points (group A 50-55%, group B 55-60%, group C > 60%). For comparison of the functional outcomes, standardized measures and scores were used (pre-OP: VAS, Lysholm; post-OP: VAS, Lysholm, KOOS). Analysis of the pre- and post-operatively recorded X-rays was effected by means of a planning software (mediCAD, Hectec GmbH, Germany), and statistical analysis was carried out using SPSS Statistics 21.0 (IBM Corp., Armonk, USA). A p value of 0.05 was considered statistically significant.

RESULTS

Thirty-nine patients were allocated to group A, 50 patients to group B and 67 to group C. Pre-operatively, patients in each group were of a homogenous constitution. In the groups A-C, HTO proved to reduce the VAS score and to increase the Lysholm score (p < 0.001). Regarding outcome parameters, group A showed significantly better results in terms of increased Lysholm (p = 0.049) and KOOS pain score (p = 0.043). In patients treated by HTO and ACI implantation for medial compartment lesions, the best results were achieved in group A which was of statistical significance in comparison of the Lysholm (p = 0.006) and VAS score (p = 0.045) of groups A and C. In this subgroup, the size of the post-operative valgus angle significantly correlated with the final VAS score (PC 0.364; p = 0.013), final Lysholm score (PC - 0.390; p = 0.007) and KOOS4 (PC - 0.356; p = 0.014).

CONCLUSION

HTO for varus deformity in patients with concomitant cartilage damage or osteoarthritis of the medial compartment is a reliable treatment option with satisfying functional outcome. Precise pre-operative planning regarding individual factors in each patient is mandatory; a pathology-based extent of correction leads to a favourable clinical outcome and to a significant reduction in pain.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

Comparison of the efficiency of an extra-articular absorber system and high tibial osteotomy for unloading the medial knee compartment: an in vitro study

PURPOSE

The unloading effect of an extra-articular absorber system on the knee joint medial compartment was compared with high tibial osteotomy (HTO) under physiological conditions in vitro.

METHODS

Seven fresh-frozen cadaveric knees were used to test isokinetic flexion-extension motions under physiological loading using a biomechanical knee simulator. Tibiofemoral area contact and peak contact pressures were measured using pressure-sensitive film in the untreated medial compartment. Pressures were measured after KineSpring System implantation and HTO (5° and 10° correction angles) performed with an angular-stable internal fixator (Tomofix).

RESULTS

Implantation of the unloading device resulted in significantly decreased medial compartment area contact pressure (Δ0.02 ± 0.01 MPa, p = 0.001) and peak contact pressure (Δ0.3 ± 0.1 MPa, p = 0.001) compared with the first test cycle results in the untreated knee. HTO significantly decreased the pressure (p = 0.001). Compared with the first test cycle, HTO (5° correction angle) decreased the mean contact pressure by Δ0.03 ± 0.01 MPa and peak contact pressure by Δ0.3 ± 0.01 MPa. With a 10° correction angle, HTO decreased contact pressure by Δ0.04 ± 0.02 MPa and peak contact pressure by Δ0.4 ± 0.1 MPa compared with that at the 5° correction angle.

CONCLUSION

Implantation of an extra-capsular unloading device resulted in a significant unloading effect on the medial compartment comparable to that achieved with HTO at 5° and 10° correction angles. Thus, implantation of an extra-articular, extra-capsular absorber could become the method of choice when treating patients with unicompartmental osteoarthritis that cannot be adequately treated by HTO because of their straight-leg axis.

High Rates of Return to Sports Activities and Work After Osteotomies Around the Knee: A Systematic Review and Meta-Analysis

BACKGROUND

Knee osteotomies are proven treatment options, especially in younger patients with unicompartmental knee osteoarthritis, for certain cases of chronic knee instability, or as concomitant treatment for meniscal repair or transplantation surgery. Presumably, these patients wish to stay active. Data on whether these patients return to sport (RTS) activities and return to work (RTW) are scarce.

OBJECTIVES

Our aim was to systematically review (1) the extent to which patients can RTS and RTW after knee osteotomy and (2) the time to RTS and RTW.

METHODS

We systematically searched the MEDLINE and Embase databases. Two authors screened and extracted data, including patient demographics, surgical technique, pre- and postoperative sports and work activities, and confounding factors. Two authors assessed methodological quality. Data on pre- and postoperative participation in sports and work were pooled.

RESULTS

We included 26 studies, involving 1321 patients (69% male). Mean age varied between 27 and 62 years, and mean follow-up was 4.8 years. The overall risk of bias was low in seven studies, moderate in ten studies, and high in nine studies. RTS was reported in 18 studies and mean RTS was 85%. Reported RTS in studies with a low risk of bias was 82%. No studies reported time to RTS. RTW was reported in 14 studies; mean RTW was 85%. Reported RTW in studies with a low risk of bias was 80%. Time to RTW varied from 10 to 22 weeks. Lastly, only 15 studies adjusted for confounders.

CONCLUSION

Eight out of ten patients returned to sport and work after knee osteotomy. No data were available on time to RTS. A trend toward performing lower-impact sports was observed. Time to RTW varied from 10 to 22 weeks, and almost all patients returned to the same or a higher workload.

Magnetic Resonance Imaging Score and Classification System (AMADEUS) for Assessment of Preoperative Cartilage Defect Severity

Objective To design a simple magnetic resonance (MR)-based assessment system for quantification of osteochondral defect severity prior to cartilage repair surgery at the knee. Design The new scoring tool was supposed to include 3 different parameters: (1) cartilage defect size, (2) depth/morphology of the cartilage defect, and (3) subchondral bone quality, resulting in a specific 3-digit code. A clearly defined numeric score was developed, resulting in a final score of 0 to 100. Defect severity grades I through IV were defined. For intra- and interobserver agreement, defects were assessed by 2 independent readers on preoperative knee MR images of n = 44 subjects who subsequently received cartilage repair surgery. For statistical analyses, mean values ± standard deviation (SD), interclass correlation coefficients (ICC), and linear weighted kappa values were calculated. Results The mean total Area Measurement And DEpth & Underlying Structures (AMADEUS) score was 48 ± 24, (range, 0-85). The mean defect size was 2.8 ± 2.6 cm². There were 36 of 44 full-thickness defects. The subchondral bone showed defects in 21 of 44 cases. Kappa values for intraobserver reliability ranged between 0.82 and 0.94. Kappa values for interobserver reliability ranged between 0.38 and 0.85. Kappa values for AMADEUS grade were 0.75 and 0.67 for intra- and interobserver agreement, respectively. ICC scores for the AMADEUS total score were 0.97 and 0.96 for intra- and interobserver agreement, respectively. Conclusions The AMADEUS score and classification system allows reliable severity encoding, scoring and grading of osteochondral defects on knee MR images, which is easily clinically applicable in daily practice.

Sport and early osteoarthritis: the role of sport in aetiology, progression and treatment of knee osteoarthritis

Sports activities are considered favourable for general health; nevertheless, a possible influence of sports practice on the development of early osteoarthritis (OA) is a cause for concern. A higher incidence of OA in knees and ankles of former high-impact sports players than in those of the normal population has been shown and it is still debatable whether the cause is either to be recognized generically in the higher number of injuries or in a joint overload. The possibility to address knee OA in its early phases may be strictly connected to the modification of specific extrinsic or intrinsic factors, related to the patient in order to save the joint from further disease progression; these include sport practice, equipment and load. Non-surgical therapies such as continuative muscles reinforce and training play a strong role in the care of athletes with early OA, particularly if professional. There is an overall agreement on the need of an early restoring of a proper meniscal, ligament and cartilage integrity in order to protect the knee and resume sports safely, whereas alignment is a point still strongly debatable especially for professional athletes. Remaining questions still to be answered are the risks of different sports in relation to one another, although an actual protective effect of low-impact sports, such as walking, swimming or cycling, has been recognized on the appearance or worsening of OA, the effect of continuing or ceasing to practice a sport on the natural history of early OA, and even following appropriate treatment is still unknown.

Mesenchymal Stem Cells for Osteochondral Tissue Engineering

Mesenchymal stem cells (MSC) are of major interest in regenerative medicine, as they are easily harvested from a variety of sources (including bone marrow and fat aspirates) and they are able to form a range of mesenchymal tissues, in vitro and in vivo. We focus here on the use of MSCs for engineering of cartilage, bone, and complex osteochondral tissue constructs, using protocols that replicate some aspects of natural mesodermal development. For engineering of human bone, we discuss some of the current advances, and highlight the use of perfusion bioreactors for supporting anatomically exact human bone grafts. For engineering of human cartilage, we discuss the limitations of current approaches, and highlight engineering of stratified, mechanically functional human cartilage interfaced with bone by mesenchymal condensation of MSCs. Taken together, current advances enable engineering of physiologically relevant bone, cartilage and osteochondral composites, and physiologically relevant studies of osteochondral development and disease.