Non-anatomical reconstruction of chronic posterolateral corner knee injuries show failure rates from 0% to 36% versus 4.3% to 24.2% for anatomic reconstruction techniques: An updated systematic review reflecting the 2019 expert consensus statement

OBJECTIVE

To review and update the literature regarding outcomes following surgical management of chronic, grade III posterolateral corner (PLC) injuries, with an emphasis on estimating failure rates based upon objective parameters in light of the 2019 expert consensus, while secondarily comparing the failure rates of anatomic versus non-anatomic reconstruction techniques.

METHODS

A literature search was performed using the PubMed, Embase, MEDLINE, and Cochrane Library databases. Inclusion criteria consisted of level I-IV human clinical studies reporting subjective and objective outcomes in patients following surgical management for chronic (>6 weeks from injury) grade III PLC injuries, with a minimum two-year follow-up. The criterion for objective surgical failure was based on post-operative varus stress radiographs and defined as a side-to-side difference of 3 ​mm or more of lateral gapping.

RESULTS

A total of six studies, consisting of 10 separate cohorts encompassing a total of 230 patients, were identified. PLC reconstruction was performed in all cohorts, with 80 ​% (n ​= ​8/10) of these cohorts utilising an anatomic reconstruction technique. A failure rate ranging from 4.3 ​% to 36 ​% was found. Subgroup analysis revealed a failure rate of 4.3 ​%-24.2 ​% for anatomic reconstruction techniques, whereas a 0 ​%-36 ​% failure rate was found for non-anatomic reconstruction. Arthrofibrosis was the most common complication (range, 0 ​%-12.1 ​%) following surgery. 0 ​%-8 ​% of patients required revision PLC surgery.

CONCLUSION

PLC reconstruction yields a wide variability in failure rates according to the side-to-side difference of 3 ​mm or more of lateral gapping on post-operative varus stress radiographs, with low revision rates following anatomic and non-anatomic reconstruction techniques.

LEVEL OF EVIDENCE

IV; Systematic Review of Level III and IV studies.

No risk of iatrogenic peroneal nerve injury in all-inside lateral meniscal repair with either 14- or 18-mm needles through the popliteus tendon in the standard arthroscopic knee conditions

PURPOSE

The objectives of this prospective study were to evaluate the risk of peroneal nerve (PN) injury in simulated all-inside lateral meniscal repair with sutures placed through the popliteus tendon (PT) and to determine the optimal needle length.

METHODS

Twenty-nine axial magnetic resonance images (MRI) of postoperative knees with infused intra-articular fluid and in a figure-of-four position were used. The cross-sectional length of the PT was divided into four equal parts with measurements performed at the 25%, 50% and 75% points according to their anteroposterior arrangement. Simulated repairs were performed with 14-mm and 18-mm straight needles via the anteromedial (AM) and anterolateral (AL) portals. Distances from the needle tip following full insertion through the PT to the PN and from the anterior PT border to the posterior knee capsule were measured to determine PN injury risk and ideal needle insertion depths at the different landmarks.

RESULTS

Simulated repairs on the 29 knee MRI images resulted in no incidences of PN injury. The average distances from the needle tip to the PN of the 14-mm needle were significantly greater than the 18-mm needle in all the simulated repairs (P < 0.02), except at the 25% point in the AM approach. When using the 14-mm needle, capsule underpenetration was found in three knees (10.3%) at the 25% point during the AM approach, in one knee (3.4%) at the 50% and 75% points in the AM approach, and in all repairs from the AL portal. The average distances from the anterior PT border to the capsule at the 25%, 50%, and 75% division points on the PT in the AM approach were 7.7 ± 2.7 mm, 7.9 ± 2.5 mm and 7.6 ± 2.8 mm, respectively, whilst in the AL approach were 8.4 ± 2.9 mm, 8.1 ± 2.8 mm and 7.6 ± 2.7 mm.

CONCLUSION

Simulated all-inside lateral meniscal repair with suture placement through the PT with 14-mm and 18-mm needles was safe. The measurements in this study can be used to determine potential PN injury risk in relation to the PT and the appropriate needle length for safe lateral meniscal repairs.

Measurement of Distance Between Femoral Insertion of Fibular Collateral Ligament and Popliteus: A Cadaveric Study in Indian Population

Background

Injuries to posterolateral corner (PLC) of knee are often neglected. The three key components of PLC are lateral collateral ligament (LCL), popliteofibular ligament (PFL) and popliteus tendon (PT). For adequate reconstruction, anatomic location of these ligaments should be well understood.

Material and methods

Twenty formalin fixed cadaveric knees were dissected. PT and LCL identified. Circumference of the two structures marked with pen just after cutting them close to bone surface. Distance between the centre of LCL and PT was measured along with the measurement of distal femoral medio-lateral dimension (MLD) and Anteroposterior dimension (ALD) of lateral condyle.

Result

The mean distance between PT and LCL measured in 20 specimens was 8.3 ± 0.84 mm, with a range of 7 mm to 10 mm. MLD was 81.0 ± 3.6 mm and APD was 62.7 ± 3.2 mm.

Conclusion

The distance in Indian population is significantly smaller compared to the western. This has clinical implication in drilling the tunnels for PLC reconstruction.

Is the popliteus tendon always inserted antero-inferiorly 18.5 mm from the lateral collateral ligament of the femur? Magnetic resonance imaging and cadaveric evaluations

BACKGROUND

The aim of this study was to analyze the locations of the femoral attachments of the popliteus tendon (PT) and lateral collateral ligament (LCL) via magnetic resonance imaging (MRI) and cadaveric dissection in a Korean population and compare with literature standards to determine whether variability exists.

METHODS

We retrospectively analyzed knee MRIs from 87 cases selected from January 2017 to December 2018. The relationship between the femoral attachment of PT and LCL was analyzed by MRI using PACS and Image J. In addition, the femoral attachments of each structure were identified and marked in 14 unpaired human cadaveric knees. Three-dimensional models were reconstructed, and the surface area, location and distances were analyzed.

RESULTS

On MRI, the femoral attachment of PT was located at mean distances of 0.89 mm posterior and 9.35 mm inferior to the LCL femoral attachment. We identified three groups of PT locations relative to the LCL on MRI evaluation: parallel (63%), posterior (29%), and anterior (8%). On cadaveric evaluation, the femoral attachment of the PT was located at mean distances of 0.77 mm posterior and 8.90 mm inferior to the LCL femoral attachment. We also identified three groups of PT locations relative to the LCL on cadaveric evaluation: parallel (43%), posterior (36%), and anterior (21%).

CONCLUSIONS

Based on both MRI and cadaveric evaluations in a Korean population, the femoral attachment of the PT is located just distal to and posterior to the LCL. The differences between the centroids of the femoral attachments of the two structures was approximately 9.7 mm, suggesting that racially based anatomical differences of the posterolateral corner may exist.

fibula osteotomy

BACKGROUND

Comminuted lateral tibial plateau fractures pose a challenge to surgeons, with non-anatomical reductions in 70-89%, involving the posterolateral articular surface. The purpose of this study was to examine the posterolateral joint visibility, using lateral extended approaches, such as the lateral femoral epicondyle osteotomy or the fibula osteotomy. Further, the study aimed to compare the combined osteotomy of the femoral footprints of the lateral collateral ligament (LCL) and popliteus tendon (PLT) to the isolated osteotomy of the femoral LCL footprint or the fibula osteotomy, in terms of posterolateral joint accessibility.

METHODS

Extended lateral (femoral or fibular LCL osteotomy) and posterolateral (additional femoral osteotomy of the PLT tendon) approaches were performed on twelve human cadaver knees. After preparation of each surgical approach, the visible articular surface was marked with diathermy. The tibial plateau was disarticulated and the markings were measured digitally with open-source processing software. Differences in mean values were tested with a paired t-test (p ≤ 0.05).

RESULTS

The greatest articular exposure was achieved with the fibula osteotomy (1011.52 ± 227.05 mm² [86.64 ± 4.84%] compared to the combined osteotomy of LCL and PLT (p = 0.036) or LCL alone (p<0.001). The lateral femoral epicondyle osteotomy of the LCL including the PLT (937.45 ± 237.84 mm² [80.29 ± 8.25%]) exposed a significantly larger articular surface of the lateral tibial plateau than without the PLT (755.71 ± 183.06 mm² [64.73 ± 6.51%], p < 0.001).

CONCLUSION

In direct comparison, the fibula osteotomy provides the largest articular visualization, however at cost of a considerably larger soft tissue damage. While the lateral femoral epicondyle osteotomy of LCL and PLT increases lateral articular visualization, it omits the risk of neurovascular or posterolateral soft tissue damage and therefore represents an important extended approach to treat comminuted lateral plateau fractures.

The evaluation of the distance between the popliteus tendon and the lateral collateral ligament footprint and the implant in Total knee Arthroplasty using a 3-dimensional template

Background

The popliteus tendon (PT) or lateral collateral ligament (LCL) stabilizes the postero-lateral aspects of the knees. When surgeons perform total knee arthroplasty (TKA), PT and LCL iatrogenic injuries are a risk because the femoral attachments are relatively close to the femoral bone resection area. The purpose of this study was to evaluate the distance between the PT or LCL footprint and the TKA implant using a 3D template system and to evaluate any significant differences according to the implant model.

Methods

Eighteen non-paired formalin fixed cadaveric lower limbs were used (average age: 80.3). Whole length lower limbs were resected from the pelvis. All the surrounding soft tissue except the PT, knee ligaments and meniscus were removed from the limb. Careful dissection of the PT and LCL was performed, and the femoral footprints were detected. Each footprint periphery was marked with a 1.5 mm K-wire. Computed tomography (CT) scanning of the whole lower limb was then performed. The CT data was analyzed with a 3D template system. This simulation models for TKA were the Journey II BCS and the Persona PS. The area of each footprint, and the length between the most distal and posterior point of the lateral femoral condyle and the edge of each footprint were measured. Matching the implant model to the CT image of the femur, the shortest length between each footprint and the bone resection area were calculated.

Results

PT and LCL footprint were detected in all knees. The area of the PT and LCL footprints was 38.7 ± 17.7 mm² and 58.0 ± 24.6 mm², respectively. The length between the most distal and posterior point of the lateral femoral condyle and the edge of the PT footprint was 10.3 ± 2.4 mm and 14.2 ± 2.8 mm, respectively. The length between most distal and most posterior point of the lateral femoral condyle and the edge of the LCL footprint was 16.3 ± 2.3 mm and 15.5 ± 3.3 mm, respectively. Under TKA simulation, the shortest length between the PT footprint and the femoral bone resection area for the Journey II BCS and the Persona PS was 4.3 ± 2.5 mm and 3.2 ± 2.9 mm, respectively. The shortest length between the LCL footprint and the femoral bone resection area for the Journey II BCS and the Persona PS was 7.2 ± 2.3 mm and 5.6 ± 2.1 mm, respectively. The PT attachment was damaged by the bone resection of the Journey II BCS and the Persona PS TKA in 3 and 9 knees, respectively.

Conclusion

The PT and LCL femoral attachments existed close to the femoral bone resection area of the TKA. To prevent postero-lateral instability in TKA, careful attention is needed to avoid damage to the PT and LCL during surgical procedures.

Increasing posterior condyle cut for high-flex knee prosthesis may injure popliteus tendon origin: A comparison between real clinical setting and cadaveric study

Background

High-flex total knee prosthesis designs were proposed to improve flexion in total knee replacement (TKA). One of high-flex features is increasing posterior condyle cut which put popliteal tendon in higher risk of injury and may result in gap changes.

Methods

Prevalence of popliteus footprint injuries were compared between conventional and high-flex TKA in real clinical setting. Thirty-six popliteal origin sites from eighteen fresh cadavers were measured distances between the posterior rim of popliteal tendon origin and posterior border of the lateral femoral condyle (distance A) using digital "Vernier caliper". The mean distances were compared to posterior condyle thickness of different prosthesis designs.

Results

The prevalence of posterior popliteus footprint injury was significantly higher in high-flex TKA compared to the conventional design TKA (17.8% vs 3.5%, p =0.005). The mean of distance A on the right knee was 9.59 mm (6.03-12.70) while the mean of distance A on the left knee was 9.13 mm (5.80-11.07). Posterior condyle thickness of the femoral prostheses varies upon their design and size from 7.4 to 10 mm for conventional model and from 8.2 to 12.5 mm for high-flex design. Possibilities of popliteal tendon injury during posterior condyle bone cut was at least 16.7% for conventional model and 27.8% for the high-flex design.

Conclusion

High-flex TKA prosthesis with thicker posterior condyle relates to higher possibility of popliteal tendon origin injury compared to standard one.

The popliteus tendon provides a safe and reliable location for all-inside meniscal repair device placement

PURPOSE

Repairs of the posterior horn of the lateral meniscus can be technically challenging. In contrast to medial meniscus repairs, the capsule around the posterior segment attachment of the lateral meniscus is quite thin. This study evaluates the clinical results of an arthroscopic all-inside repair technique for unstable, vertical, lateral meniscus tears, using a suture repair placed directly into the popliteus tendon.

METHODS

A retrospective analysis of prospectively collected data from the SANTI database was performed. All patients who had undergone combined ACL reconstruction with lateral meniscus all-inside repair, using sutures placed in the popliteus tendon, between 2011 and 2015, were included. Patients were reviewed clinically at 1 and 2 years' follow-up. At final follow-up, all patients were contacted to identify if they underwent further surgery or had knee pain, locking or effusion. Symptomatic patients were recalled for clinical evaluation by a physician and Magnetic Resonance Imaging of the knee. Operative notes for those undergoing further surgery were reviewed and rates and type of re-operation, including for failed lateral meniscal repair were recorded.

RESULTS

Two hundred patients (mean age 28.6 ± 10.2 years) with a mean follow-up of 45.5 ± 12.8 months (range 24.7-75.2) were included. The mean Subjective International Knee Documentation Committee (IKDC) at final follow-up was 85.0 ± 11.3. The post-operative mean side-to-side laxity measured at 1 year was 0.6 ± 1.0 mm. Twenty-six patients underwent re-operation (13%) at a mean follow-up of 14.8 ± 7.8 months. The ACL graft rupture rate was 5.0%. Other causes for re-operation included medial meniscus tear (2.5%), cyclops lesion (1.5%) and septic arthritis (0.5%). The lateral meniscus repair failure rate was 3.5%. No specific complications relating to placement of sutures in the popliteus tendon were identified.

CONCLUSION

Arthroscopic all-inside repair of unstable, vertical, lateral meniscus tears using a suture placed in the popliteus tendon is a safe technique. It is associated with a very low failure rate with no specific complications.

LEVEL OF EVIDENCE

Level IV.

Non-Operative Rehabilitation of Isolated Popliteus Tendon Rupture in a Rugby Player

Isolated rupture of the popliteus tendon is uncommon; instead, it is often seen as part of multi-ligamentous posterolateral corner injuries. In this report, we present a case of a 22-year-old professional rugby player who sustained a lateral blow to his semi-flexed knee in a tackle during a competitive game. A complete popliteus tendon rupture at its musculo-tendinous junction was diagnosed on magnetic resonance imaging despite a relatively unremarkable physical examination. The aims of this report are to highlight the diagnostic challenges with this rare injury as physical signs are often subtle and non-specific. Furthermore, we demonstrate the viability of conservative management in the setting of a direct contact mechanism. Indeed, our patient was successfully treated with a specific rehabilitation protocol via isometric quadriceps contractions, gastrocnemius-soleus and hamstring strengthening exercises and graded activity with successful return to full contact activities at 4 weeks and regular season matches shortly after.

Midterm outcomes following anatomic-based popliteus tendon reconstructions

PURPOSE

The purpose of this study was to document subjective outcomes following anatomic-based reconstruction of the popliteus tendon when the popliteus tendon was the only injured posterolateral knee structure. It was hypothesized that popliteus tendon reconstruction would result in improved patient outcomes after surgery regardless of the concurrent ligamentous or intra articular pathology.

METHODS

A consecutive series of 5 patients with a median age of 23 years (range, 22-36 years) who underwent anatomic popliteus tendon reconstruction along with concomitant ligament reconstruction or meniscus repair (if needed) were included in this study. All patients completed pre-operative and post-operative subjective questionnaires, which included the Lysholm score to document function, the Tegner activity scale to document activity level, and a patient satisfaction with outcome question.

RESULTS

All patients were available for a final follow-up at a median time of 2.8 years (range, 2-3.9 years) following the index surgery. Three patients had a combined popliteus tendon and posterior cruciate ligament reconstruction. Two of the three PCL reconstructions were revision procedures. The Lysholm score improved to from 53 (range, 34-90) to 91 (range, 44-100) at post-operative follow-up. The median pre-operative Tegner activity scale improved from 3 (range, 0-9) to a median score of 4.8 (range, 2-7) at post-operative follow-up. The median patient satisfaction with outcome was 9 (range, 7-10). The dial test at 30° and 90° improved in all patients following surgery.

CONCLUSIONS

Anatomic-based popliteus tendon reconstructions resulted in improved outcomes and a high patient satisfaction in patients with a complete tear of the popliteus tendon and symptomatic knee instability.

LEVEL OF EVIDENCE

IV, case series.

Femoral footprint of the popliteus tendon may be at the risk of damage during total knee arthroplasty

PURPOSE

The present study focused on the prevalence of incidental excision of the femoral footprint of the popliteus tendon during total knee arthroplasty and its associated risk factors.

METHODS

A total of 275 knee arthroplasties were performed for 226 patients with varus knee osteoarthritis. The status of the femoral footprint of the popliteus tendon was intraoperatively evaluated and classified into three groups (preserved, partially excised, and completely excised), and the prevalence of the excision was identified. Femoral component size, the thickness of the resected distal femoral condyle, and preoperative patient demographic data were compared for the three groups. Ordinal logistic regression analysis was performed to reveal risk factors associated with the excision.

RESULTS

The femoral footprint of the popliteus tendon was preserved in 132 knees (48.0 %), partially excised in 94 knees (34.2 %) and completely excised in 49 knees (17.8 %). The ordinal logistic regression analysis revealed thicker resection of the distal femoral condyle (p < 0.0001) and shorter body height (p = 0.0266) to be the independent risk factors for the excision.

CONCLUSIONS

The incidental partial or complete excision of the femoral footprint of the popliteus tendon was identified in approximately half of the evaluated knees. Thicker resection of the distal femoral condyle and shorter body height were the most significant risk factors for the excision.

LEVEL OF EVIDENCE

Case-control study, Level III.

Acute calcific tendinopathy of the popliteus tendon: a rare case diagnosed using a multimodality imaging approach and treated conservatively

Acute calcific tendinopathy of the popliteus tendon is a rare medical entity associated with significant patient discomfort. We present the case of a previously healthy 48-year-old female who presented to the emergency department with acute onset of left knee pain. Initial radiographs revealed calcifications within the posterolateral compartment of the knee. Ultrasound imaging demonstrated a swollen and hypoechoic popliteus tendon with an increased color Doppler signal at the periphery of the tendon as well as calcification in the tendon and adjacent soft tissues. Subsequently performed MRI revealed a thickened and heterogeneous popliteus tendon near its femoral attachment with marked edematous changes surrounding the tendon. Local ultrasound-guided glucocorticoid injection had successful clinical results with no recurrence at 8-month follow-up. In this case report we review the literature for similar previously reported cases. This case report of popliteus tendon calcific tendinopathy provides comprehensive multimodality imaging findings and a description of its non-surgical management.

Popliteus impingement after TKA may occur with well-sized prostheses

PURPOSE

To determine the mechanisms and extents of popliteus impingements before and after TKA and to investigate the influence of implant sizing. The hypotheses were that (1) popliteus impingements after TKA may occur at both the tibia and the femur, and (2) even with an apparently well-sized prosthesis, popliteal tracking during knee flexion is modified compared to the preoperative situation.

METHODS

The location of the popliteus in three cadaver knees was measured using computed tomography, before and after implantation of plastic TKA replicas, by injecting the tendon with radiopaque liquid. The pre- and post-operative positions of the popliteus were compared from full extension to deep flexion using normosized, oversized, and undersized implants (one size increments).

RESULTS

At the tibia, TKA caused the popliteus to translate posteriorly, mostly in full extension: 4.1 ± 2 mm for normosized implants, and 15.8 ± 3 mm with oversized implants, but no translations were observed when using undersized implants. At the femur, TKA caused the popliteus to translate laterally at deeper flexion angles, peaking between 80° and 120°: 2 ± 0.4 mm for normosized implants and 2.6 ± 0.5 mm with oversized implants. Three-dimensional analysis revealed prosthetic overhang at the posterosuperior corner of normosized and oversized femoral components (respectively, up to 2.9 mm and 6.6 mm).

CONCLUSIONS

A well-sized tibial component modifies popliteal tracking, while an undersized tibial component maintains more physiologic patterns. Oversizing shifts the popliteus considerably throughout the full arc of motion. This study suggests that both femoro- and tibio-popliteus impingements could play a role in residual pain and stiffness after TKA.

Imaging the implant-soft tissue interactions in total knee arthroplasty

Background

In Total Knee Arthroplasty (TKA), residual pain may be secondary to soft tissue impingements, which are difficult to visualize around chromium-cobalt implants using medical imaging, so their interactions remain poorly understood. The goal of this work was to establish a protocol for in-vitro imaging of the soft tissues around TKA, usable during throughout the range of motion (ROM).

Methods

The full size range of a commercially available TKA prosthesis was manufactured by 3D-printing in non-magnetic and non-radiopaque polymer and implanted in 12 cadaveric knees. The relations between these implants and the soft tissues (Popliteus tendon, Medial and Lateral Collateral Ligament, Patellar and Quadriceps tendons) were analyzed, using MRI (5 embalmed specimens) and CT scans after injection of the tissues with barium-sulfate (3 embalmed and 4 fresh-frozen specimens).

Results

Both MRI and CT scans enabled good identification of the soft tissues before TKA implantation. MRI produced minimal loss in signal and contrast, and neither the low temperature nor the embalming fluids compromised image quality. CT scans were more precise after TKA implantation, particularly the borders of the implant and the differentiation of soft tissues. Full ROM investigation, manual segmentation and three-dimensional reconstructions were possible only with the CT scan.

Conclusion

The experimental approach described in this study was successful in visualizing the interactions between the soft tissue and the implants before and after TKA and during the full ROM. The coordinate system allows to localize precisely the different anatomic structures and to quantify any change due to prosthetic implantation.

A new method for the evaluation of the end-to-end distance of the knee ligaments and popliteal complex during passive knee flexion

BACKGROUND

Accurate knowledge about the length variation of the knee ligaments (ACL, PCL, MCL and LCL) and the popliteal complex during knee flexion/extension is essential for modelling and clinical applications. The aim of the present study is to provide this information by using an original technique able to faithfully reproduce the continuous passive knee flexion-extension kinematics and to reliably identify each ligament/tendon attachment site.

METHODS

Twelve lower limbs (femur, tibia, fibula, patella) were tested and set in motion (0-120°) using an ad hoc rig. Tibio-femoral kinematics was obtained using an optoelectronic system. A 3D digital model of each bone was obtained using low-dosage stereoradiography. Knee specimens were dissected and the insertion of each ligament and popliteal complex were marked with radio opaque paint. ACL, PCL and MCL were separated into two bundles. Bone epiphyses were CT-scanned to obtain a digital model of each ligament insertion. Bones and attachment site models were registered and the end-to-end distance variation of each ligament/tendon was computed over knee flexion.

RESULTS

A tibial internal rotation of 18°±4° with respect to the femur was observed. The different bundles of the ACL, MCL and LCL shortened, whereas all bundles of the PCL lengthened. The popliteal complex was found to shorten until 30° of knee flexion and then to lengthen.

CONCLUSION

The end-to-end distance variation of the knee ligaments and popliteal complex can be estimated during knee flexion using a robust and reliable method based on marking the ligaments/tendon insertions with radiopaque paint.

LEVEL OF EVIDENCE

Level IV.

Surgical management of isolated popliteus tendon injuries in paediatric patients

Isolated popliteus avulsion injuries are a rare occurrence, especially in the skeletally immature population. Two cases of isolated popliteus tendon avulsion injuries in paediatric patients were identified and successfully managed with suture anchor reattachment of the avulsed fragment in the anatomic position. The objective of this case report is to raise awareness of orthopaedic surgeons to the rarely encountered isolated popliteus tendon injury that can occur in paediatric patients. Level of evidence Expert opinion, Level V.

Arthroscopic popliteus bypass graft for posterolateral instabilities of the knee : A new surgical technique

Objective

An arthroscopic technique for the reconstruction of the posterolateral corner combined with posterior cruciate ligament (PCL) reconstruction was developed.

Indications

Posterolateral rotational instabilities of the knee. Combined lesions of the PCL, the popliteus complex (PLT) and the posterolateral corner. Isolated PLT lesions lacking static stabilizing function.

Contraindications

Neuromuscular disorders; knee deformities or fractures; severe posterolateral soft tissue damage.

Surgical technique

Six arthroscopic portals are necessary. Using the posteromedial portal, resect dorsal septum with a shaver. Visualize the PCL, the lateral femoral condyle and the posterolateral recessus with the PLT. Dissect the popliteomeniscal fibers; retract PLT until sulcus popliteus is visualized. Drill a 6-mm tunnel anteriorly into the distal third of the sulcus popliteus. Visualize femoral footprint of the PLT and place an anatomical drill tunnel. Pull the popliteus bypass graft into the knee and fix with bioscrews. Fix the reconstructed PCL. In cases of additional LCL injury, reconstruct LCL with autologous graft.

Postoperative management

Partial weight-bearing for 6 weeks, range of motion exercises, quadriceps-strengthening exercises on postoperative day 1. Full extension allowed immediately with flexion limited to 20° for 2 weeks, to 45° for up to week 4, and to 60° up to week 6. Use a PCL brace for 3 months, running and squatting exercises allowed after 3 months.

Results

In the 35 patients treated, no technique-related complications. After 1 year, 12 patients had a mean Lysholm Score of 88.6 (± 8.7) points and a side-to-side difference in the posterior drawer test of 2.9 (± 2.2) mm (preoperative 13.3 [± 1.9] mm).

Conclusion

Low complication risk and good and excellent clinical results after arthroscopic posterolateral corner reconstruction.

Long-term clinical outcomes of combined BPTB ACL reconstruction and popliteus tendon plasty

PURPOSE

A deficiency of posterolateral structures significantly increases the varus load on the ACL, while a chronic ACL lesion, the increased tibial rotation and the repetitive non-physiological knee motion, could affect and damage the integrity of the popliteus tendon. Therefore, the aim of the present study was to report the very long clinical outcomes of a combined single-bundle BPTB ACL reconstruction and popliteus plasty according to Bousquets technique, for the treatment of combined chronic anterior and posterolateral laxities.

METHODS

Fifteen patients that underwent combined ACL reconstruction and popliteal plasty according to Bousquets technique were available at mean 26.8 ± 1.0 years (range 25.4-28.0 years). All the patients were evaluated clinically and 13 by means of KT-1000 Arthrometer as well. Subjective evaluation was performed with the subjective IKDC, WOMAC and a 0-10 VAS for pain scales.

RESULTS

At clinical evaluation, 10 patients (67 %) presented a negative anterior drawer test; Lachman test was negative in nine patients (60 %); the varus stress test was negative in eight (53 %); and the dial test was negative in all but one patient (93 %). Only two patients (15 %) presented a side-to-side difference >5 mm at the instrumented laxity evaluation.

CONCLUSION

The combined single-bundle BPTB ACL reconstruction and popliteal plasty according to Bousquets technique were able to produce very good long-term results, in terms of knee stability, subjective outcomes, functional results and return to sport activity, in case of chronic anterior and posterolateral laxities.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Arthroscopic reconstruction of the popliteus complex: accuracy and reproducibility of a new surgical technique

PURPOSE

With combined PCL reconstruction and a minimal invasive (extra-anatomical) Larson's procedure, dorsal instability can be reduced by about 50-70 %. Better results are described by open and more anatomical procedures. In this study, a new, standardized, arthroscopic technique for anatomical popliteus tendon (PLT) reconstruction is evaluated.

METHODS

In 13 cadaver knees, an arthroscopic reconstruction of the PLT and the lateral collateral ligament was performed. Twelve defined landmarks were used for arthroscopic tunnel placement, and the distance of the tunnel locations to these specific landmarks was evaluated.

RESULTS

The femoral drill channel was located with a high degree of accuracy and reproducibility in the centre of the femoral footprint of the PLT (on average 1.1 (±1.6) mm distal from the centre). On the tibial side, the drill channel was in the distal third of the sulcus popliteus in all cases. On average, the channel was placed exactly at the level of the tip of the fibula (±1.5 mm) and 0.6 (±1.7) mm medially from the medial edge of the fibula. The centre of the channel was 13.4 (±2.3) mm distal from the joint line.

CONCLUSIONS

The presented arthroscopic technique for PLT reconstruction is standardized, reproducible and has a high accuracy for the placement of the tibial and femoral tunnel. The technique could be clinically relevant for future arthroscopic posterolateral corner reconstructions.

LEVEL OF EVIDENCE

III.

Morphology of the femoral insertion of the lateral collateral ligament and popliteus tendon

PURPOSE

To clarify the femoral insertion of the lateral collateral ligament (LCL) and popliteus tendon (PT) and related osseous landmarks on three-dimensional images.

METHODS

Twenty-six non-paired, formalin-fixed human cadaveric knees were evaluated in this study. Femoral insertion of the LCL and PT was identified and marked. Three-dimensional images were created, and the surface area, location, positional relationships, and morphology of the femoral insertion of the LCL, PT, and related osseous structures were analysed.

RESULTS

The mean surface areas of the LCL and PT femoral insertions were 55.8 ± 25.0 and 52.5 ± 24.2 mm(2), respectively. Variations in the positional relationships between the LCL and PT insertions (PT inserted parallel and posterior to the LCL insertion to the long axis of the femur) were observed. The lateral epicondyle and popliteal sulcus could be clearly identified as osseous landmarks on three-dimensional images in all knees. Most of the LCL was inserted postero-distal to the apex of the lateral epicondyle, and the PT was inserted at the anterior end of the popliteal sulcus in all knees.

CONCLUSION

We observed variation in the positional relationship between the femoral insertion of the LCL and PT. However, the relationships between their insertions and osseous landmarks were consistent. The findings of this study contribute to the understanding of the PLC osseous anatomy and should assist surgeons in performing PLC surgery with a more anatomic perspective.