In arthritic knees with severe valgus deformity Total Knee Arthroplasty (TKA) can be performed through medial or lateral parapatellar approaches. Many orthopaedic surgeons are apprehensive of using the lateral parapatellar approach due to lack of familiarity and concerns about complications related to soft tissue coverage and vascularity of the patella and the overlying skin. However surgeons who use this approach report good outcomes and no added complications. The purpose of our study was to compare outcomes following TKA performed through a medial parapatellar approach with those performed through a lateral parapatellar approach in arthritic knees with severe valgus deformity.

We conducted a retrospective review of patients from two consultants using computer navigation for all their TKAs. All patients with severe valgus deformities (Ranawat 2 & 3 grades) operated on between January 2005 and December 2011 were included. 66 patients with 67 TKAs fulfilled the inclusion criteria. Patients were group by approach; Medial = 34TKAs (34 patients) or Lateral = 33 TKAs (32 patients). Details were collected from patients' records, AP hip-knee-ankle (HKA) radiographs and computer navigation files. Outcome measures included lateral release rates, post-operative range of knee movements, long leg mechanical alignment measurements, post-operative Oxford scores at six weeks and one year, patient satisfaction and any complications. Comparisons were made between groups using t-tests.

The total cohort had a mean age of 69 years [42–82] and mean BMI of 29 [19–46]. The two groups had comparable pre-operative Oxford scores (Medial 41[27–56], Lateral 44 [31–60]) and pre-operative valgus deformity measured on HKA radiographs (Medial 13° [10°–27.6°], Lateral 12° [6°–22°]). Three patients in the Medial group underwent intra-operative lateral patellar release to improve patellar tracking. Seven patients in the Lateral group had a lateral condyle osteotomy for soft tissue balancing (one bilateral). There was no statistically significant difference between groups at one year follow up for maximum flexion (Medial 100° [78°–122°], Lateral 100° [85°–125°], p=0.42), fixed flexion deformity (Medial 1.2° [0°–10°], Lateral 0.9° [0°–10°], p=0.31) or Oxford score (Medial 23 [12–37], Lateral 23 [16–41], p=0.49). Similarly there was no difference in the patient satisfaction rates between the two groups at one year follow up. However there was a statistically significant difference in the mean radiographic post-operative alignment angle measurement (Medial 1.8° valgus [4° varus to 10° valgus], Lateral 0.3° valgus [5° varus to 7° valgus], p=0.02). One patient in the Medial group had a revision to hinged knee prosthesis for post-operative instability. There was no wound breakdown or patellar avascular necrosis noted in either of the groups.

The lateral parapatellar approach resulted in slightly better valgus correction on radiographs taken six weeks post-operatively. We found no major complications in the Lateral parapatellar approach group. Specifically we did not encounter any difficulties in closing the deep soft tissue envelope around the knee and there were no cases of patellar avascular necrosis or skin necrosis. Hence we conclude that lateral parapatellar approach is a safe and reliable alternative to the medial parapatellar approach for correction of severe valgus deformity in TKA.

Patient reported outcome measures (PROMs) are important for assessing the results of lower limb arthroplasty. Unrealistic or uneducated expectations may have a significant negative impact on PROMs even when surgery is technically successful. This study's aim was to quantify pre-operative expectations of Scottish patients undergoing total hip and knee replacement (THR/TKR).

100 THR and 100 TKR patients completed validated questionnaires (from the Hospital for Special Surgery) prior to their operation after receiving standard pre-operative information (booklet, DVD, consultations). Each patient rated expectations from very important to not having the expectation. A total score was calculated using a numerical scale for the grading of each expectation. Univariate regression analysis was used to investigate the relationship between demographics and expectation score.

The THR cohort had mean age 66.2 (SD 10.5), 53% female, mean BMI 29.0 (SD 5.1) and mean Oxford score 44 (SD 7). The TKR cohort had mean age 67.6 (SD 8.5), 59% female, mean BMI 32.8 (SD 5.8) and mean Oxford score 44 (SD 8). 100% THR and 96% TKR patients had 10 or more expectations of their operation. All expected pain relief. Other improvements expected were: walking for 100% THA and 99% TKA patients; daily activities for 100% THAs and 96% TKAs; recreational activities for 96% THAs and 93% TKAs; sexual activity for 66% THAs and 59% TKAs; psychological well-being for 98% THAs and 91% TKAs. Regression analysis showed increasing age lowered expectations in both THR (p=0.025) and TKR (p=0.031) patients but that gender, BMI and Oxford score were not significantly related to expectations.

This study highlights that patients expect far more than pain relief and improved post-operative mobility from their operation. It is important to discuss and manage these expectations with patients prior to surgery. By doing so, patient satisfaction and PROMs should further improve.